WO2022270108A1 - Redox flow battery system - Google Patents

Redox flow battery system Download PDF

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Publication number
WO2022270108A1
WO2022270108A1 PCT/JP2022/015672 JP2022015672W WO2022270108A1 WO 2022270108 A1 WO2022270108 A1 WO 2022270108A1 JP 2022015672 W JP2022015672 W JP 2022015672W WO 2022270108 A1 WO2022270108 A1 WO 2022270108A1
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WIPO (PCT)
Prior art keywords
electrolyte
positive electrode
negative electrode
state
cell
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PCT/JP2022/015672
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French (fr)
Japanese (ja)
Inventor
恭裕 内藤
宏一 加來
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住友電気工業株式会社
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Publication of WO2022270108A1 publication Critical patent/WO2022270108A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/04537—Electric variables
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
    • H01M8/04858—Electric variables
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/18—Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the present disclosure relates to redox flow battery systems.
  • This application claims priority based on Japanese Patent Application No. 2021-102300 filed in Japan on June 21, 2021, and incorporates all the content described in the Japanese application.
  • Patent Document 1 discloses a manganese-titanium redox flow battery using a positive electrode electrolyte containing manganese ions and a negative electrode electrolyte containing titanium ions. If manganese ions are contained in the positive electrode electrolyte, manganese oxide (MnO 2 ) may precipitate during charging and discharging. Patent document 1 suppresses deposition of manganese oxide by containing titanium ions in addition to manganese ions in the positive electrode electrolyte.
  • the redox flow battery system of the present disclosure comprises bank and a controller that controls the state of charge of the bank;
  • the bank is a battery cell; a positive electrode tank in which a positive electrode electrolyte circulating in the battery cell is stored; a negative electrode tank in which a negative electrode electrolyte circulating in the battery cell is stored;
  • a power conversion device that controls charging and discharging of the battery cell The controller comprises a first controller that controls the power conversion device so that the state of charge of the battery cell is held in a specific state for 10 seconds or more, The specific state is at least one of a first state and a second state,
  • the first state is a state in which the state of charge of the electrolyte in the battery cell differs from the state of charge of the positive electrode electrolyte in the positive electrode tank by 5% or more
  • the second state is a state in which the charge state of the electrolyte in the battery cell differs from the charge state of the negative electrode electrolyte in the negative electrode tank by 5% or more
  • FIG. 1 is a schematic configuration diagram showing the basic configuration of the redox flow battery system of the embodiment.
  • FIG. 2 is a schematic configuration diagram showing a state during normal operation in the redox flow battery system of Embodiment 1-1.
  • FIG. 3 is a schematic configuration diagram showing the state of the redox flow battery system of Embodiment 1-1 during recovery work of the electrolytic solution.
  • FIG. 4 is a schematic configuration diagram showing a state during normal operation in the redox flow battery system of Embodiment 1-2.
  • FIG. 5 is a schematic diagram showing the state of the redox flow battery system of Embodiment 1-2 during recovery work of the electrolytic solution.
  • FIG. 6 is a schematic configuration diagram showing the configuration of the redox flow battery system of Embodiment 2.
  • FIG. 7 is a schematic configuration diagram showing the configuration of the redox flow battery system of Embodiment 3.
  • FIG. 8 is a schematic configuration diagram showing the configuration of the redox flow battery system of Embodiment 4.
  • Redox flow battery systems are required to have higher energy densities. If the energy density can be increased, the battery capacity can be increased.
  • One of the means to increase the energy density of the redox flow battery is to expand the range of utilization of the state of charge (SOC) of the electrolyte. However, with the expansion of the range of utilization of SOC, side reactions such as deposition of oxides are likely to occur within the battery cells constituting the redox flow battery.
  • SOC state of charge
  • a by-reactant generated in the battery cell adheres to the electrode, for example. Adhesion of the by-reactants to the electrode reduces the performance of the electrode and adversely affects the battery performance.
  • One of the purposes of the present disclosure is to provide a redox flow battery system that can improve battery performance degradation due to side reactions while achieving high energy density.
  • the redox flow battery system of the present disclosure can improve battery performance degradation due to side reactions while achieving high energy density.
  • a redox flow battery system bank and a controller that controls the state of charge of the bank;
  • the bank is a battery cell; a positive electrode tank in which a positive electrode electrolyte circulating in the battery cell is stored; a negative electrode tank in which a negative electrode electrolyte circulating in the battery cell is stored;
  • a power conversion device that controls charging and discharging of the battery cell,
  • the controller comprises a first controller that controls the power conversion device so that the state of charge of the battery cell is held in a specific state for 10 seconds or more,
  • the specific state is at least one of a first state and a second state
  • the first state is a state in which the state of charge of the electrolyte in the battery cell differs from the state of charge of the positive electrode electrolyte in the positive electrode tank by 5% or more
  • the second state is a state in which the charge state of the electrolyte in the battery cell differs from the charge state of the negative electrode electrolyte in the negative electrode tank by 5% or more.
  • the charged state of the battery cells is maintained in a specific state for 10 seconds or longer, thereby redissolving the by-reactants generated in the battery cells.
  • the redox flow battery system of the present disclosure can re-dissolve the side-reactant even if the side-reactant is generated in the battery cell to restore the performance of the electrode. Since the redox flow battery system of the present disclosure is capable of recovering the electrolytic solution by redissolving the by-reactant, it is possible to expand the usage range of the state of charge of the electrolytic solution. As described above, the redox flow battery system of the present disclosure can improve battery performance degradation due to side reactions while achieving high energy density.
  • redissolving the side reaction product is broadly defined as restoring the state of the electrolytic solution, which has changed due to charging or discharging within a specific SOC range, to its original state.
  • This definition is not limited to converting solid deposits back into ions in the electrolyte.
  • This definition includes with or without a gas/solid/liquid phase change.
  • an electrolytic solution containing a solid active material such as zinc it also includes controlling the amount of electrodeposition.
  • An active material may deposit on the surface of an electrode by a side reaction. When deposits from side reactions adhere to the electrode, the reactivity of the electrode deteriorates. That is, the battery performance is degraded.
  • a catalyst or the like may be adhered to the surface of the electrode. Even if the deposit due to the side reaction deposits so as to cover the catalyst and the like, the performance of the battery is lowered. By re-dissolving the precipitate adhering to the surface of the electrode, the condition of the surface of the electrode can be maintained. Thereby, deterioration of battery performance can be suppressed.
  • the specific state may be maintained for 10 minutes or less.
  • Charging or discharging during normal operation means expanding the usage range of the state of charge of the electrolyte beyond the usage range of the main SOC, which will be described later, so that the redox flow battery system is connected to an external power source or load. It is the charging or discharging that occurs.
  • the operation may be restricted, such as stopping the normal operation of the redox flow battery system.
  • the by-reactants generated in the battery cells can be redissolved, and the effects on the normal operation of the redox flow battery system can be suppressed in a short period of time.
  • the battery cell includes a positive electrode cell and a negative electrode cell, a first positive electrode circuit for returning the positive electrode electrolyte from the positive electrode tank to the positive electrode tank through the positive electrode cell; a first negative electrode circulation path returning the negative electrode electrolyte from the negative electrode tank to the negative electrode tank through the negative electrode cell; a second positive electrode circuit for returning the positive electrode electrolyte from the positive electrode tank to the positive electrode tank via the negative electrode cell; and a second positive electrode circuit for returning the negative electrode electrolyte from the negative electrode tank to the negative electrode tank via the positive electrode cell.
  • the controller may include a second controller that controls the operation of the first switching section or the second switching section.
  • the first positive electrode circuit circulates the positive electrode electrolyte to the positive electrode cell
  • the first negative electrode circuit circulates the negative electrode electrolyte to the negative electrode cell.
  • the electrolyte solution of opposite polarity is circulated through the positive electrode cell or the negative electrode cell.
  • the second negative electrode circuit circulates the negative electrode electrolyte in the positive electrode cell.
  • the second positive electrode circuit circulates the positive electrode electrolyte in the negative electrode cell.
  • the controller performs charging or discharging such that the difference between the charged state at the inlet side of the electrolyte supplied to the battery cell and the charged state at the outlet side of the electrolyte discharged from the battery cell is 10% or more.
  • a third controller may be provided that controls the power conversion device to perform
  • the equipment used in the normal operation of the redox flow battery system can be used as it is, or the above equipment can be used with a simple modification to reduce the amount of electrolyte in the battery cell.
  • the charging state can be set to a specific state.
  • the third controller may control the power converter so that the charging or discharging is performed at a current density of 300 mA/cm 2 or higher.
  • Charging or discharging at a current density of 300 mA/cm 2 or higher tends to bring the state of charge of the electrolyte in the battery cell into a specific state.
  • the third controller controls the charging or discharging when the flow rate of the electrolytic solution supplied to the battery cell is 4.0 cc/min/cm 2 or less. You may control the said power converter to perform.
  • the first state is a state in which the state of charge of the electrolyte in the battery cell differs from the state of charge of the positive electrode electrolyte in the positive electrode tank by 15% or more
  • the second state may be a state in which the charge state of the electrolyte in the battery cell differs from the charge state of the negative electrode electrolyte in the negative electrode tank by 15% or more.
  • a plurality of the banks are provided,
  • the controller controls the power conversion device provided in each of the plurality of banks so that the state of charge of the battery cells provided in each of the plurality of banks sequentially becomes the specific state among the plurality of banks.
  • a rotating controller may be provided.
  • the controller includes a rotatable controller
  • the rotatable controller can cause the battery cells in each bank to be placed in a particular state in sequence from bank to bank. Specifically, in the bank where the recovery work of the electrolyte in the battery cell is performed, the state of charge of the electrolyte in the battery cell can be set to a specific state. On the other hand, in the bank in which the recovery work of the electrolyte in the battery cell is not performed, the state of charge of the electrolyte in the battery cell can be brought to the state of normal operation. In other words, the rotatable controller enables recovery of the electrolyte in the battery cells without stopping the normal operation of the redox flow battery system.
  • the RF battery system 1 of the embodiment includes a bank 2 and a controller 9 that controls the SOC of the bank 2, as shown in FIG.
  • Bank 2 includes battery cells 10 , positive electrode tank 22 , negative electrode tank 23 , and power conversion device 8 .
  • One or a plurality of banks 2 are provided.
  • the controller 9 has a first controller 91 .
  • the first controller 91 controls the power conversion device 8 so that the SOC of the battery cell 10 is held in a specific state for 10 seconds or longer.
  • the specific state is at least one of the first state and the second state.
  • the first state is a state in which the SOC of the electrolyte in the battery cell 10 differs from the SOC of the cathode electrolyte in the cathode tank 22 by 5% or more.
  • the second state is a state in which the SOC of the electrolyte in the battery cell 10 differs from the SOC of the anode electrolyte in the anode tank 23 by 5% or more.
  • the RF battery system 1 is typically connected to an external power supply 810 and load 820 via a substation facility 800 .
  • the RF battery system 1 can charge power supplied from the power supply 810 and discharge the charged power to the load 820 .
  • the power source 810 is, for example, power generation equipment using natural energy such as solar power generation or wind power generation, or other general power plants.
  • the load 820 is, for example, a power system or a power consumer.
  • the RF battery system 1 is used, for example, for load leveling, momentary sag compensation, emergency power supply, and output smoothing of natural energy power generation.
  • the range of utilization of the state of charge of the electrolytic solution is expanded to the range of utilization of the main SOC, which will be described later, plus the range of utilization of the sub-SOC.
  • the operation of the RF battery system 1 that is expanded and charged or discharged is called normal operation.
  • ⁇ bank ⁇ Bank 2 is a secondary battery unit system that charges or discharges a power system.
  • the bank 2 includes battery cells 10 , a circulation mechanism that circulates an electrolytic solution in the battery cells 10 , and a power converter 8 that controls charging and discharging of the battery cells 10 .
  • the bank 2 is charged or discharged by circulating the electrolyte in the battery cells 10 .
  • charging and discharging of the battery cells 10 of each bank 2 are independently controlled by each power conversion device 8 .
  • a battery cell 10 is separated into a positive electrode cell 12 and a negative electrode cell 13 by a diaphragm 11 .
  • a positive electrode 14 is incorporated in the positive electrode cell 12 .
  • a positive electrode electrolyte is supplied to the positive electrode cell 12 .
  • a negative electrode 15 is incorporated in the negative electrode cell 13 .
  • a negative electrode electrolyte is supplied to the negative electrode cell 13 .
  • the battery cells 10 are typically used in a form called a cell stack 200 in which a plurality of battery cells 10 are stacked.
  • the cell stack 200 includes a cell frame 100, a positive electrode 14, a diaphragm 11, a negative electrode 15, and another cell frame 100, which are repeatedly stacked, two end plates 201 sandwiching the stack, and a fastening member 202.
  • the tightening member 202 is, for example, a long bolt and nut.
  • the two end plates 201 are clamped by clamping members 202 . By this tightening, the laminated state of the laminated body is maintained.
  • the cell stack 200 is typically used in a form in which a predetermined number of battery cells 10 are used as substacks (not shown), and a plurality of substacks are stacked.
  • Supply/discharge plates (not shown) are arranged outside the cell frames 100 positioned at both ends in the stacking direction of the battery cells 10 in the sub-stack or cell stack 200 .
  • the cell frame 100 includes a frame 110 and a bipolar plate 112.
  • Frame 110 is provided on the outer periphery of bipolar plate 112 .
  • a positive electrode 14 and a negative electrode 15 are housed inside the frame 110 with a bipolar plate 112 interposed therebetween.
  • One battery cell 10 is configured by arranging the positive electrode 14 and the negative electrode 15 between the bipolar plates 112 of the adjacent cell frames 100 with the diaphragm 11 interposed therebetween.
  • a sealing member 150 is arranged between the frames 110 to prevent the electrolyte from leaking from the battery cells 10 .
  • the circulation mechanism includes a positive electrode circulation mechanism that circulates the positive electrode electrolyte in the positive electrode cells 12 and a negative electrode circulation mechanism that circulates the negative electrode electrolyte in the negative electrode cells 13 .
  • the positive electrode circulation mechanism includes a positive electrode tank 22 , an outward pipe 24 , a return pipe 26 and a pump 28 .
  • a positive electrode electrolyte is stored in the positive electrode tank 22 .
  • Outbound pipe 24 and return pipe 26 connect between positive electrode tank 22 and positive electrode cell 12 .
  • a pump 28 is provided in the forward line 24 on the supply side.
  • the negative electrode circulation mechanism includes a negative electrode tank 23 , an outward pipe 25 , a return pipe 27 and a pump 29 .
  • a negative electrode electrolyte is stored in the negative electrode tank 23 .
  • Outbound pipe 25 and return pipe 27 connect between negative electrode tank 23 and negative electrode cell 13 .
  • the pump 29 is provided in the outward line pipe 25 on the supply side.
  • the positive electrode electrolyte is supplied from the positive electrode tank 22 to the positive electrode cell 12 through the outbound pipe 24 and returned from the positive electrode cell 12 to the positive electrode tank 22 through the return pipe 26 .
  • the negative electrode electrolyte is supplied from the negative electrode tank 23 to the negative electrode cell 13 through the forward pipe 25 and returned from the negative electrode cell 13 to the negative electrode tank 23 through the return pipe 27 .
  • the electrolytic solution is a solution containing active material ions.
  • An active material ion is an ion that functions as an active material.
  • Active material ions are typically metal ions whose valences change due to oxidation-reduction.
  • Active material ions are, for example, ions of elements selected from the group consisting of manganese, vanadium, iron, chromium, titanium, and zinc.
  • At least one of the positive electrode electrolyte and the negative electrode electrolyte has the following characteristics. (1) Depending on the SOC range during charging or discharging, a side reaction occurs and a side reaction product is produced. (2) It is possible to redissolve the side reactants by a reversible reaction.
  • a side reaction product produced by a side reaction is, for example, a deposit of active material ions.
  • the electrolytic solution is, for example, an electrolytic solution containing manganese ions.
  • the manganese ions may precipitate as manganese oxide in the electrolyte in the high SOC region during charging.
  • Manganese oxide can be decomposed into manganese ions and redissolved in the electrolytic solution by the recovery operation of the electrolytic solution, which will be described later.
  • the positive electrode electrolyte is an electrolyte containing manganese ions
  • the negative electrode electrolyte is an electrolyte containing titanium ions, for example.
  • the power conversion device 8 controls charging and discharging of the battery cells 10 .
  • the battery cells 10 are charged and discharged via the power conversion device 8 .
  • the charging and discharging of the battery cells 10 of each bank 2 are independently controlled by the power conversion device 8 of each bank 2 .
  • an AC/DC converter can be used as the power conversion device 8 .
  • Controller 9 controls the SOC of bank 2 .
  • the SOC of bank 2 is the SOC of the electrolyte in the battery cell 10 in bank 2 .
  • the controller 9 controls the power conversion device 8 of each bank 2 to control the SOC of each bank 2 .
  • the controller 9 includes a basic controller 90 that controls the power conversion device 8 so that the battery cells 10 are charged or discharged within the expanded range of the main SOC.
  • the basic controller 90 operates during normal operation of the RF battery system 1 . During normal operation, the power system connected to the power supply 810 and the load 820 is charged or discharged.
  • the controller 9 includes a first controller 91 that controls the power converter 8 so that the SOC of the battery cell 10 is held in a specific state for 10 seconds or longer.
  • the first controller 91 operates during recovery work of the electrolyte in the bank 2 .
  • the work of recovering the electrolyte in bank 2 is to re-dissolve the side reaction products generated in the battery cells 10 in bank 2 .
  • Side reactants are produced within the battery cells 10 during normal operation of the RF battery system 1 .
  • the side reactants adhere to constituent members within the battery cell 10, such as electrodes.
  • the battery cells 10 forming the bank 2 do not charge or discharge the electric power system.
  • the controller 9 issues a command to the power conversion device 8 of bank 2.
  • the controller 9 issues commands to the power converters 8 of each bank 2 .
  • the power conversion device 8 of bank 2 controls charging and discharging of the battery cells 10 based on commands from the controller 9 .
  • the controller 9 causes the basic controller 90 to control the power conversion device so that the battery cells 10 are charged or discharged at an SOC within an expanded range of the main SOC.
  • Command 8 When the controller 9 does not charge or discharge the electric power system and restores the electrolyte in the bank 2, the first controller 91 keeps the SOC of the battery cell 10 in a specific state for 10 seconds or more.
  • a command is issued to the power conversion device 8 so that the
  • a computer for example, can be used as the controller 9.
  • a computer includes a processor, memory, timers, and the like.
  • the memory stores a control program to be executed by the processor and various data.
  • the processor reads and executes the control program stored in the memory.
  • the program contains instructions for processing by controller 9 .
  • the SOC of the battery cell 10 differs during normal operation of the RF battery system 1 and during recovery work of the electrolyte.
  • the SOC of the battery cell 10 here is the average value of the SOC on the inlet side of the electrolyte supplied to the battery cell 10 and the SOC on the outlet side of the electrolyte discharged from the battery cell 10 .
  • ⁇ be the SOC on the inlet side of the electrolyte supplied to the battery cell 10 .
  • ⁇ be the SOC on the outlet side of the electrolyte discharged from the battery cell 10 .
  • the average value of the SOC of the battery cells 10 is a value obtained by ( ⁇ + ⁇ )/2.
  • the inlet-side SOC of the electrolytic solution supplied to the battery cell 10 is the SOC of the electrolytic solution flowing through the forward pipes 24 and 25 .
  • the outlet-side SOC of the electrolyte discharged from the battery cell 10 is the SOC of the electrolyte flowing through the return pipes 26 and 27 .
  • the main SOC utilization range is the SOC range in which side reactions are less likely to occur and side reaction products are less likely to be generated.
  • the range of SOC in which side reaction products are less likely to be generated is, for example, the total amount of elements that become active materials contained in the electrolytic solution when charging and discharging for one week within a certain SOC range is set to 100 mol%. In this case, the ratio of the active material consumed in the production of the by-reactant is 10 mol % or less.
  • the period of charging and discharging within the above SOC range may be two weeks, or even one month.
  • the ratio of the active material consumed in the production of the above side reaction products is preferably 5 mol % or less, more preferably 1 mol % or less.
  • a positive electrode electrolyte containing manganese ions as an active material when manganese oxide is produced as a side-reactant, manganese is consumed in the production of the side-reactant.
  • the expanded range of usage of the main SOC includes, in addition to the range of usage of the main SOC, the range of sub-SOC where side reactions occur due to charging and discharging and side reactants are generated.
  • the sub-SOC range includes at least one of the high SOC region and the low SOC region.
  • the high SOC region is a region in which the SOC is higher than the upper limit of the main SOC utilization range.
  • the low SOC region is a region in which the SOC is lower than the lower limit of the main SOC utilization range. Side reactants may be generated in the high SOC region and the low SOC region.
  • the usable range of the main SOC varies depending on the electrolyte used.
  • the usable range of the main SOC is determined in advance by a test using the electrolytic solution to be used.
  • a range that is wider than the range of utilization of the main SOC, that is, each range of the high SOC region and the low SOC region may be set as appropriate.
  • the range of the high SOC region or the range of the low SOC region is, for example, 5% or more, further 10% or more, particularly 15% or more of the size of the main SOC utilization range.
  • the size of the utilization range is the difference between the upper limit and the lower limit of the utilization range.
  • the main SOC utilization range is 20% to 80%.
  • the range of the high SOC region is 10% of the size of the available range
  • the SOC utilization range combining the main SOC utilization range and the high SOC region is from 20% to 86%.
  • the SOC utilization range is expanded by 10% from the main SOC utilization range, so the battery capacity of bank 2 is increased by 10%.
  • the range of the low SOC region is 10% of the size of the usable range
  • the usable range of SOC is from 14% to 80%. In this case as well, the battery capacity of bank 2 will increase by 10%.
  • the electrolytic solution may be, for example, a vanadium-based electrolytic solution.
  • both the positive electrode electrolyte and the negative electrode electrolyte contain vanadium ions.
  • the vanadium ions in the positive electrode electrolyte and the vanadium ions in the negative electrode electrolyte have different valences.
  • the main SOC utilization range is approximately 5% to 95%.
  • the range obtained by adding the usage range of the sub SOC to the usage range of the main SOC is the SOC range of the battery cell 10 during normal operation.
  • the SOC of the electrolyte in the battery cell 10 is substantially the same as the SOC of the cathode electrolyte in the cathode tank 22 and the SOC of the anode electrolyte in the anode tank 23. is substantially the same as “Substantially the same” means that the difference between the SOC of the electrolyte in the battery cell 10 and the SOC of the cathode electrolyte in the cathode tank 22 is less than 5%, and the SOC of the electrolyte in the battery cell 10 and the anode It means that the difference from the SOC of the negative electrode electrolyte in the tank 23 is less than 5%.
  • the SOC of the battery cells 10 is controlled to a specific state by the first controller 91 during the recovery work of the electrolyte in the bank 2 .
  • the specific state is at least one of the first state and the second state.
  • the first state is a state in which the SOC of the electrolyte in the battery cell 10 differs from the SOC of the cathode electrolyte in the cathode tank 22 by 5% or more.
  • the second state is a state in which the SOC of the electrolyte in the battery cell 10 differs from the SOC of the anode electrolyte in the anode tank 23 by 5% or more.
  • the side-reactant may be re-dissolved in a region lower than the main SOC utilization range.
  • the area where the SOC is lower than the main SOC utilization range includes a low SOC area and an area where the SOC is even lower than the low SOC area. If a side-reactant is produced in the low SOC region, the side-reactant may be re-dissolved in the higher SOC region than the main SOC utilization range.
  • the area where the SOC is higher than the main SOC utilization range includes a high SOC area and an area where the SOC is higher than the high SOC area.
  • the difference may be 8% or more, 10% or more, 12% or more, 15% or more.
  • the difference may be 50% or more, 100% or more, or 150% or more.
  • the above difference is less than 200%, even less than 180%, especially less than 170%, less than 160%.
  • the difference is, for example, 5% or more and less than 200%, 50% or more and 180% or less, 100% or more and 170% or less, or 150% or more and 160% or less.
  • the above difference is 50% or less, and further 45% due to the use of the RF battery system 1. below, especially below 40%.
  • the difference is, for example, 5% or more and 50% or less, 8% or more and 50% or less, 10% or more and 50% or less, 12% or more and 45% or less, 15% or more and 40%. % or less.
  • the time for which the SOC of the battery cell 10 is held in the specific state is 10 seconds or longer.
  • the side reaction product can be redissolved.
  • the longer the time the easier it is to re-dissolve the side reaction product.
  • the time may also be 30 seconds or more, 1 minute or more, 2 minutes or more, especially 3 minutes or more.
  • the above time is, for example, 10 minutes or less. If the SOC of the battery cell 10 is in the specific state, the by-reactant generated in the battery cell 10 can be redissolved even in a short time of 10 minutes or less.
  • the time is, for example, 10 seconds or more and 10 minutes or less, further 30 seconds or more and 10 minutes or less, 1 minute or more and 10 minutes or less, 2 minutes or more and 10 minutes or less, particularly 3 minutes or more and 10 minutes or less.
  • the SOC of the electrolyte in the battery cell 10, that is, the SOC of the battery cell 10, is the SOC at the inlet side of the electrolyte supplied to the battery cell 10 and the SOC at the outlet of the electrolyte discharged from the battery cell 10, as described above. It is the average value with the SOC on the side.
  • the inlet-side SOC can be measured, for example, by using a monitor cell to which the same electrolytic solution as that supplied to the battery cell 10 is supplied.
  • the electrolyte supplied to the battery cells 10 and the electrolyte supplied to the monitor cells are supplied from the same tank.
  • the SOC on the inlet side is measured using a monitor cell 60 configured by a part of the cells of the cell stack 200.
  • FIG. The monitor cell 60 does not charge or discharge.
  • a monitor cell 61 different from the cell stack 200 is used to measure the SOC on the inlet side.
  • the monitor cell 61 is provided upstream of the battery cell 10 .
  • the monitor cell 61 is connected to branch pipes provided in each of the forward pipe 24 through which the positive electrode electrolyte flows and the forward pipe 25 through which the negative electrode electrolyte is flowed.
  • the monitor cell 61 does not charge or discharge.
  • the monitor cells 60 and 61 can obtain the SOC from their open circuit voltage (OCV: Open Circuit Voltage) using a voltmeter.
  • OCV Open Circuit Voltage
  • Embodiment 1 instead of the monitor cell 60, a monitor cell 61 similar to that of Embodiments 2 and 3 may be used to measure the inlet-side SOC. In Embodiments 2 and 3, instead of the monitor cell 61, a monitor cell 60 similar to that of Embodiment 1 may be used to measure the inlet-side SOC.
  • the SOC on the outlet side can be calculated from the SOC on the inlet side, the flow rate of the electrolyte flowing through the battery cell 10, and the current density of the electrolyte flowing through the battery cell 10.
  • the outlet-side SOC can also be measured using a monitor cell provided downstream of the battery cell 10 .
  • a monitor cell is provided downstream of the battery cell 10
  • this monitor cell is connected to branch pipes provided in each of the return pipe 26 through which the positive electrode electrolyte flows and the return pipe 27 through which the negative electrode electrolyte flows.
  • the inlet side When measuring the SOC on the outlet side using a monitor cell provided downstream of the battery cell 10, the measurement result, the flow rate of the electrolyte flowing through the battery cell 10, and the current density of the electrolyte flowing through the battery cell 10, the inlet side can also be calculated.
  • the SOC of the positive electrode electrolyte in the positive electrode tank 22 or the SOC of the negative electrode electrolyte in the negative electrode tank 23 can be calculated using the monitor cell that measures the SOC on the inlet side.
  • the monitor cell 60 is used for calculation.
  • ⁇ Means for setting the SOC of the battery cell to a specific state There are, for example, the following three forms of means for setting the SOC of the battery cell 10 to a specific state.
  • the first mode when the side reactant is generated in the high SOC region, the reverse polarity electrolyte is circulated to the positive electrode cell 12 or the negative electrode cell 13 where the side reactant is generated. be.
  • the second mode is a mode in which when a side reactant is generated in a high SOC region, the side reactant is redissolved by performing short-time discharge.
  • a third mode is a mode in which, when a side reactant is generated in a low SOC region, the side reactant is redissolved by charging for a short period of time.
  • the bank 2 includes a first positive electrode circuit 31, a first negative electrode circuit 41, and at least one of the second positive electrode circuit 32 and the second negative electrode circuit 42. and Moreover, in the first form, the bank 2 includes at least one of the first switching section and the second switching section.
  • the controller 9 comprises a second controller 92 that controls the operation of the first switching section or the second switching section.
  • the first positive electrode circulation path 31 is a circulation path that returns the positive electrode electrolyte from the positive electrode tank 22 to the positive electrode tank 22 via the positive electrode cell 12 .
  • the first positive electrode circulation path 31 corresponds to the outward piping 24 and the return piping 26 shown in FIG.
  • the first negative electrode circulation path 41 is a circulation path for returning the negative electrode electrolyte from the negative electrode tank 23 to the negative electrode tank 23 via the negative electrode cell 13 .
  • the first negative electrode circulation path 41 corresponds to the outward piping 25 and the return piping 27 shown in FIG. 2 to 5, the pumps 28, 29 shown in FIG. 1 are omitted.
  • the second positive electrode circulation path 32 is a circulation path that returns the positive electrode electrolyte from the positive electrode tank 22 to the positive electrode tank 22 via the negative electrode cell 13 .
  • the second negative electrode circulation path 42 is a circulation path that returns the negative electrode electrolyte from the negative electrode tank 23 to the negative electrode tank 23 via the positive electrode cell 12 .
  • the second positive electrode circuit 32 and the second negative electrode circuit 42 are not included in the basic configuration of the RF battery system 1 . Therefore, the second positive circuit 32 and the second negative circuit 42 are not shown in FIG.
  • the first switching section is a switching section that switches between the first positive electrode circulation path 31 and the second negative electrode circulation path 42 .
  • the first switching part is a valve.
  • the second switching section is a switching section that switches between the first negative electrode circulation path 41 and the second positive electrode circulation path 32 .
  • a second switching unit is a valve. The specific arrangement and number of valves will be described later.
  • the second controller 92 controls each valve to switch.
  • the controller 9 does not charge or discharge the electric power system such as the power supply 810 and the load 820, and when the recovery work of the electrolyte in the bank 2 is performed, the second controller 92 instructs to switch each valve. out.
  • the first controller 91 of the controller 9 issues a command to the power conversion device 8 so that the SOC of the battery cell 10 is held in a specific state for 10 seconds or longer.
  • each valve is switched to circulate the electrolyte solution of the opposite polarity for 10 seconds or more to the cell in which the side reaction product is generated among the positive electrode cell 12 and the negative electrode cell 13 .
  • the difference between the SOC of the electrolyte solution in the battery cell 10 and the SOC of the cathode electrolyte solution in the cathode tank 22 or the SOC of the anode electrolyte solution in the anode tank 23 is It is the difference between the SOC of one of the liquid and the negative electrode electrolyte and the SOC of the other.
  • the SOC of the positive electrode electrolyte and the negative electrode electrolyte is 80%, and the negative electrode electrolyte is circulated in the positive electrode cell 12, the SOC of the negative electrode electrolyte viewed from the SOC of the positive electrode electrolyte is ⁇ 80%. , the difference is 160%.
  • the first negative electrode circuit 41, the second positive electrode circuit 32, the second negative electrode circuit 42, the first switching unit, and the second switching unit piping and valves The number, position, etc. are changed. Two arrangements are described below.
  • Embodiment 1-1 the first arrangement mode will be described with reference to FIGS. 2 and 3.
  • FIG. both the second positive electrode circuit 32 and the second negative electrode circuit 42 are provided.
  • a main outbound pipe 33 and branch outbound pipes 34 a and 34 b are provided as pipes for supplying the positive electrode electrolyte from the positive electrode tank 22 to the battery cells 10 .
  • the main outbound pipe 33 is connected to the positive electrode tank 22 .
  • a pump (not shown) is provided in the main outbound pipe 33 .
  • the branch outbound pipe 34 a is connected to the main outbound pipe 33 and the positive electrode cell 12 .
  • a valve 37a is provided on the forward branch pipe 34a.
  • the outbound branch pipe 34 b is connected to the main outbound pipe 33 and the negative electrode cell 13 .
  • a valve 37b is provided on the forward branch pipe 34b.
  • a main return pipe 35 and branch return pipes 36 a and 36 b are provided as pipes for returning the positive electrode electrolyte from the battery cell 10 to the positive electrode tank 22 .
  • the main return pipe 35 is connected to the positive electrode tank 22 .
  • the branch return pipe 36 a is connected to the main return pipe 35 and the positive electrode cell 12 .
  • a valve 38a is provided in the branch return pipe 36a.
  • the branch return pipe 36 b is connected to the main return pipe 35 and the negative electrode cell 13 .
  • a valve 38b is provided in the branch return pipe 36b.
  • the valves 37a and 38a are opened in order to allow the positive electrode electrolyte to flow through the first positive electrode circulation path 31.
  • Valves 37b and 38b are closed.
  • the positive electrode electrolyte is supplied from the positive electrode tank 22 to the positive electrode cell 12 through the main outbound pipe 33 and the branched outbound pipe 34a, and from the positive electrode cell 12 to the branched return pipe 36a and the main return pipe 35. is returned to the positive electrode tank 22 through .
  • the valves 37b and 38b are opened in order to allow the positive electrode electrolyte to flow through the second positive electrode circulation path 32.
  • Valves 37a and 38a are closed.
  • the positive electrode electrolyte is supplied from the positive electrode tank 22 to the negative electrode cell 13 through the main outbound pipe 33 and the branched outbound pipe 34b. is returned to the positive electrode tank 22 through .
  • a main outbound pipe 43 and branch outbound pipes 44 a and 44 b are provided as pipes for supplying the negative electrode electrolyte from the negative electrode tank 23 to the battery cells 10 .
  • the main outbound pipe 43 is connected to the negative electrode tank 23 .
  • a pump (not shown) is provided in the main outbound pipe 43 .
  • the branch outbound pipe 44 a is connected to the main outbound pipe 43 and the negative electrode cell 13 .
  • a valve 47a is provided on the forward branch pipe 44a.
  • the branch outbound pipe 44 b is connected to the main outbound pipe 43 and the positive electrode cell 12 .
  • a valve 47b is provided on the forward branch pipe 44b.
  • a main return pipe 45 and branch return pipes 46 a and 46 b are provided as pipes for returning the negative electrode electrolyte from the battery cell 10 to the negative electrode tank 23 .
  • the main return pipe 45 is connected to the negative electrode tank 23 .
  • the branch return pipe 46 a is connected to the main return pipe 45 and the negative electrode cell 13 .
  • a valve 48a is provided in the branch return pipe 46a.
  • the branch return pipe 46 b is connected to the main return pipe 45 and the positive electrode cell 12 .
  • a valve 48b is provided in the branch return pipe 46b.
  • valves 47a and 48a are opened in order to allow the negative electrode electrolyte to flow through the first negative electrode circulation path 41.
  • Valve 47b and valve 48b are closed.
  • the negative electrode electrolyte is supplied from the negative electrode tank 23 to the negative electrode cell 13 through the main outbound pipe 43 and the branched outbound pipe 44a. is returned to the negative electrode tank 23 through .
  • valves 47b and 48b are opened in order to allow the negative electrode electrolyte to flow through the second negative electrode circuit 42.
  • Valve 47a and valve 48a are closed.
  • the negative electrode electrolyte is supplied from the negative electrode tank 23 to the positive electrode cell 12 through the main outbound pipe 43 and the branched outbound pipe 44b. is returned to the negative electrode tank 23 through .
  • valves 37a, 47b, 38a, and 48b are the first switching parts.
  • Valves 37b, 47a, 38b, and 48a are second switching units.
  • the second controller 92 circulates the positive electrode electrolyte in the positive electrode cell 12 and circulates the negative electrode electrolyte in the negative electrode cell 13. control the operation of the During normal operation of the RF battery system 1, the second controller 92 opens the valves 37a, 38a, 47a, 48a and closes the valves 37b, 38b, 47b, 48b.
  • a negative electrode electrolyte is circulated.
  • the white arrows shown in FIG. 2 indicate the flow of the electrolytic solution.
  • Thick-line pipes 33, 34a, 36a, and 35 shown in FIG. 2 are pipes through which the positive electrode electrolyte is distributed.
  • Thick-line pipes 43, 44a, 46a, and 45 shown in FIG. 2 are pipes through which the negative electrode electrolyte is distributed.
  • the second controller 92 circulates the electrolyte of opposite polarity to the positive electrode cell 12 and the negative electrode cell 13 in which the side reaction product is generated. It controls the operation of the switching unit or the second switching unit. For example, when a by-reactant is generated in the positive electrode cell 12 , the second controller 92 controls the operation of the first switching section so that the negative electrode electrolyte is circulated through the positive electrode cell 12 .
  • the second controller 92 switches between the valves 37a and 47b and switches between the valves 38a and 48b as a first switching unit that switches between the first positive electrode circulation path 31 and the second negative electrode circulation path 42 .
  • the second controller 92 opens the valves 47a, 48a, 47b, 48b and closes the valves 37a, 38a, 37b, 38b.
  • the negative electrode electrolyte is circulated to the negative electrode cell 13 by The white arrows shown in FIG. 3 indicate the flow of the electrolytic solution.
  • Thick-line pipes 43, 44a, 44b, 46a, 46b, and 45 shown in FIG. 3 are pipes through which the negative electrode electrolyte flows.
  • the negative electrode electrolyte is circulated in the positive electrode cell 12 in the recovery operation of the electrolyte in the bank 2, but the positive electrode electrolyte does not have to be circulated in the negative electrode cell 13. .
  • the second positive electrode circuit 32 shown in FIGS. 2 and 3 can be omitted.
  • the second controller 92 controls the operation of the second switching unit so that the positive electrode electrolyte is circulated through the negative electrode cell 13.
  • the second controller 92 switches between the valves 37b and 47a as a second switching unit for switching between the first negative electrode circuit 41 and the second positive electrode circuit 32, and switches between the valves 38b and 48a. switch.
  • the positive electrode electrolyte When a side reaction product is generated only in the negative electrode cell 13, the positive electrode electrolyte is circulated in the negative electrode cell 13 in the recovery operation of the electrolyte in the bank 2, but the negative electrode electrolyte does not have to be circulated in the positive electrode cell 12. .
  • the second negative electrode circuit 42 shown in FIGS. 2 and 3 can be omitted.
  • the positive electrode cell 12 or the negative electrode cell 13 electrolyte solution of opposite polarity can be circulated.
  • the negative electrode electrolyte can be circulated through the positive electrode cell 12 .
  • the SOC of the electrolyte in the battery cell 10 can be brought to a specific state, and the side reaction product generated in the positive electrode cell 12 can be redissolved.
  • Embodiment 1-2 a second arrangement mode will be described with reference to FIGS. 4 and 5.
  • FIG. both the second positive electrode circuit 32 and the second negative electrode circuit 42 are provided.
  • a main outbound pipe 33 a and a common outbound pipe 39 a are provided as pipes for supplying the positive electrode electrolyte from the positive electrode tank 22 to the positive electrode cell 12 .
  • the main outbound pipe 33 a is connected to the positive electrode tank 22 .
  • a pump (not shown) is provided in the main outbound pipe 33a.
  • Common outbound pipe 39 a is connected to main outbound pipe 33 a and positive electrode cell 12 .
  • the positive electrode electrolyte flows through the common outward pipe 39a, and the negative electrode electrolyte may flow through the switching of the three-way valve 390a, which will be described later.
  • a main return pipe 35 a and a common return pipe 39 c are provided as pipes for returning the positive electrode electrolyte from the positive electrode cell 12 to the positive electrode tank 22 .
  • the main return pipe 35 a is connected to the positive electrode tank 22 .
  • the common return pipe 39 c is connected to the main return pipe 35 a and the positive electrode cell 12 .
  • the positive electrode electrolyte flows through the common return pipe 39c during normal operation, and the negative electrode electrolyte may flow through the switching of the three-way valve 390c, which will be described later.
  • a main outbound pipe 33 b and a common outbound pipe 39 b are provided as pipes for supplying the positive electrode electrolyte from the positive electrode tank 22 to the negative electrode cell 13 .
  • the main outbound pipe 33 b is connected to the positive electrode tank 22 .
  • a pump (not shown) is provided in the main outbound pipe 33b.
  • the common outbound pipe 39 b is connected to the main outbound pipe 33 b and the negative electrode cell 13 .
  • the negative electrode electrolyte flows through the common outward pipe 39b, and the positive electrode electrolyte may flow through the switching of the three-way valve 390b, which will be described later.
  • a main return pipe 35 b and a common return pipe 39 d are provided as pipes for returning the positive electrode electrolyte from the negative electrode cell 13 to the positive electrode tank 22 .
  • the main return pipe 35 b is connected to the positive electrode tank 22 .
  • the common return pipe 39 d is connected to the main return pipe 35 b and the negative electrode cell 13 .
  • a negative electrode electrolyte flows through the common return pipe 39d during normal operation, and a positive electrode electrolyte may flow through the common return pipe 39d by switching a three-way valve 390d, which will be described later.
  • a main outbound pipe 43 b and a common outbound pipe 39 b are provided as pipes for supplying the negative electrode electrolyte from the negative electrode tank 23 to the negative electrode cell 13 .
  • the main outbound pipe 33 b is connected to the negative electrode tank 23 .
  • a pump (not shown) is provided in the main outbound pipe 33b.
  • the common outbound pipe 39 b is connected to the main outbound pipe 43 b and the negative electrode cell 13 .
  • a main return line 45b and a common return line 39d are provided as piping for returning the negative electrode electrolyte from the negative electrode cell 13 to the negative electrode tank 23 .
  • the main return pipe 45 b is connected to the negative electrode tank 23 .
  • the common return pipe 39 d is connected to the main return pipe 45 b and the negative electrode cell 13 .
  • a main outbound pipe 43 a and a common outbound pipe 39 a are provided as pipes for supplying the negative electrode electrolyte from the negative electrode tank 23 to the positive electrode cell 12 .
  • the main outbound pipe 43 a is connected to the negative electrode tank 23 .
  • a pump (not shown) is provided in the main outbound pipe 43a.
  • the common outbound pipe 39 a is connected to the main outbound pipe 43 a and the positive electrode cell 12 .
  • a main return pipe 45 a and a common return pipe 39 c are provided as pipes for returning the negative electrode electrolyte from the positive electrode cell 12 to the negative electrode tank 23 .
  • the main return pipe 45 a is connected to the negative electrode tank 23 .
  • the common return pipe 39 c is connected to the main return pipe 45 a and the positive electrode cell 12 .
  • a three-way valve 390a is provided at a connection point between the common outward pipe 39a, the main outward pipe 33a, and the main outward pipe 43a. By switching the three-way valve 390a, it is possible to switch whether the positive electrode electrolyte flows from the main outward pipe 33a to the common outward pipe 39a or the negative electrode electrolyte flows from the main outward pipe 43a to the common outward pipe 39a.
  • a three-way valve 390b is provided at a connection point between the common outward pipe 39b, the main outward pipe 33b, and the main outward pipe 43b.
  • a three-way valve 390c is provided at a connection point between the common return pipe 39c, the main return pipe 35a, and the main return pipe 45a.
  • a three-way valve 390d is provided at a connection point between the common return pipe 39d, the main return pipe 35b, and the main return pipe 45b. By switching the three-way valve 390d, depending on the polarity of the electrolyte discharged from the negative electrode cell 13, the positive electrode electrolyte flows from the common return pipe 39d to the main return pipe 35b, or from the common return pipe 39d to the main return pipe 45b. It is possible to switch whether the electrolytic solution flows.
  • the three-way valve 390a connects the main outward piping 33a and the common outward piping 39a, and blocks the main outward piping 43a and the common outward piping 39a.
  • the three-way valve 390c connects the main return pipe 35a and the common return pipe 39c, and blocks the main return pipe 45a and the common return pipe 39c.
  • the positive electrode electrolyte is supplied from the positive electrode tank 22 to the positive electrode cell 12 through the main outward pipe 33a and the common outward pipe 39a, and from the positive electrode cell 12, the common return pipe 39c and the main return pipe 35a. is returned to the positive electrode tank 22 through .
  • the three-way valve 390b communicates the main outward piping 33b and the common outward piping 39b, and blocks the main outward piping 43b and the common outward piping 39b.
  • the three-way valve 390d communicates the main return pipe 35b and the common return pipe 39d, and shuts off the main return pipe 45b and the common return pipe 39d.
  • the positive electrode electrolyte is supplied from the positive electrode tank 22 to the negative electrode cell 13 through the main outbound pipe 33b and the common outbound pipe 39b, and from the negative electrode cell 13 through the common return pipe 39d and the main return pipe 35b. is returned to the positive electrode tank 22 through .
  • the three-way valve 390b communicates the main outward piping 43b and the common outward piping 39b, and blocks the main outward piping 33b and the common outward piping 39b.
  • the three-way valve 390d connects the main return pipe 45b and the common return pipe 39d, and shuts off the main return pipe 35b and the common return pipe 39d.
  • the negative electrode electrolyte is supplied from the negative electrode tank 23 to the negative electrode cell 13 through the main outbound pipe 43b and the common outbound pipe 39b, and from the negative electrode cell 13, the common return pipe 39d and the main return pipe 45b. is returned to the negative electrode tank 23 through .
  • the three-way valve 390a communicates the main outward piping 43a and the common outward piping 39a, and blocks the main outward piping 33a and the common outward piping 39a.
  • the three-way valve 390c connects the main return pipe 45a and the common return pipe 39c, and blocks the main return pipe 35a and the common return pipe 39c.
  • the negative electrode electrolyte is supplied from the negative electrode tank 23 to the positive electrode cell 12 through the main outbound pipe 43a and the common outbound pipe 39a, and from the positive electrode cell 12, the common return pipe 39c and the main return pipe 45a. is returned to the negative electrode tank 23 through .
  • the three-way valves 390a and 390c are the first switching parts.
  • Three-way valves 390b and 390d are second switching units.
  • the second controller 92 circulates the positive electrode electrolyte in the positive electrode cell 12 and circulates the negative electrode electrolyte in the negative electrode cell 13. control the operation of the During normal operation of the RF battery system 1, the second controller 92 causes the three-way valve 390a to connect the main outbound pipe 33a and the common outward pipe 39a, and the three-way valve 390c to connect the common return pipe 39c and the main return pipe 35a. It will be in a state of communication.
  • the second controller 92 causes the three-way valve 390b to communicate the main outward pipe 43b and the common outward pipe 39b, and the three-way valve 390d to communicate the common return pipe 39d and the main return pipe 45b. are in communication with each other.
  • a negative electrode electrolyte is circulated.
  • the white arrows shown in FIG. 4 indicate the flow of the electrolytic solution.
  • Thick-line pipes 33a, 39a, 39c, and 35a shown in FIG. 4 are pipes through which the positive electrode electrolyte flows.
  • Thick-line pipes 43b, 39b, 39d, and 45b shown in FIG. 4 are pipes through which the negative electrode electrolyte flows.
  • the second controller 92 circulates the electrolyte of opposite polarity to the positive electrode cell 12 and the negative electrode cell 13 in which the side reaction product is generated. It controls the operation of the switching unit or the second switching unit. For example, when a by-reactant is generated in the positive electrode cell 12 , the second controller 92 controls the operation of the first switching section so that the negative electrode electrolyte is circulated through the positive electrode cell 12 .
  • the second controller 92 operates the three-way valve 390a as a first switching unit for switching between the first positive electrode circulation path 31 and the second negative electrode circulation path 42 so that the main outward piping 43a and the common outward piping 39a communicate with each other.
  • the three-way valve 390c is switched so that the common return pipe 39c and the main return pipe 45a are communicated with each other.
  • the negative electrode electrolyte is circulated in the White arrows shown in FIG. 5 indicate the flow of the electrolytic solution.
  • Thick-line pipes 43a, 43b, 39a, 39b, 39c, 39d, 45a, and 45b shown in FIG. 5 are pipes through which the negative electrode electrolyte flows.
  • the second controller 92 controls the operation of the second switching unit so that the positive electrode electrolyte is circulated through the negative electrode cell 13.
  • the second controller 92 serves as a second switching unit for switching between the first negative electrode circulation path 41 and the second positive electrode circulation path 32, and is a three-way switch so that the main outward piping 33b and the common outward piping 39b communicate with each other.
  • the three-way valve 390d is switched so that the common return pipe 39d and the main return pipe 35b are communicated.
  • the positive electrode cell 12 or the negative electrode cell 13 can be circulated with electrolyte solutions of opposite polarities.
  • Embodiment 2 the above-described second form will be described with reference to FIG.
  • the side reactants are redissolved by performing a short-time discharge.
  • the battery cell 10 is provided with the variable resistance section 71 .
  • the controller 9 comprises a third controller 93 .
  • the variable resistance section 71 is provided between the positive electrode cell 12 and the negative electrode cell 13 that constitute the battery cell 10 .
  • a switch (not shown) is provided between the battery cell 10 and the variable resistance section 71 . By switching this switch, the battery cell 10 discharges to the variable resistance section 71 . Discharge may be started and stopped simply by changing the resistance value of the variable resistance section 71 without using a switch. The electric power supplied to the variable resistance section 71 by the discharge is consumed by resistance heating. By discharging from the battery cell 10 to the variable resistance section 71, the SOC of the battery cell 10 is lowered. The SOC of the battery cell 10 changes according to the resistance value of the variable resistance section 71 .
  • the third controller 93 performs discharge so that the difference between the SOC on the inlet side of the electrolyte supplied to the battery cell 10 and the SOC on the outlet side of the electrolyte discharged from the battery cell 10 is 10% or more. to control the power conversion device 8.
  • the difference is 10% or more, the SOC of the electrolyte in the battery cell 10 is in a specific state.
  • the larger the difference the easier it is for the SOC of the electrolyte in the battery cell 10 to reach the specific state.
  • said difference may also be 16% or more, 20% or more, 24% or more, in particular 30% or more.
  • the above difference is 100% or less, further 90% or less, 80% or less, especially 75% or less, 70% or less.
  • the third controller 93 controls the power conversion device 8 so as to discharge in a short period of time, for example, 10 minutes or less, so that the difference becomes 10% or more.
  • the current density and the flow rate of the electrolytic solution can be appropriately selected so that the side reaction product in the battery cell 10 can be redissolved in a short period of time.
  • the current density is, for example, 300 mA/cm 2 or higher, 400 mA/cm 2 or higher, 500 mA/cm 2 or higher, particularly 600 mA/cm 2 or higher.
  • the flow rate of the electrolytic solution is, for example, 4.0 cc/min/cm 2 or less, 3.0 cc/min/cm 2 or less, 2.0 cc/min/cm 2 or less, particularly 0.0 cc/min/cm 2 or less.
  • the flow rate of the electrolytic solution is the amount of electrolytic solution that flows into the battery cell 10 .
  • the unit of the flow rate of the electrolytic solution is "cc/min/cm 2 ", which indicates the volume of the electrolytic solution that flows per 1 cm 2 of the electrode in the battery cell 10 for 1 minute.
  • the fact that the flow rate of the electrolytic solution is 0.0 cc/min/cm 2 means that the electrolytic solution does not flow in the battery cell 10 and that the electrolytic solution is not circulated. Matters relating to the flow rate of the electrolyte also apply to charging, which will be described later.
  • the flow rate of the electrolytic solution is set to 2.0 cc/min/cm 2 or less, and the variable resistance section 71 is set to a high resistance value to discharge from the battery cell 10 to the variable resistance section 71 .
  • the SOC of the electrolyte discharged from the battery cell 10 on the outlet side becomes low.
  • the RF battery system 1 is provided with a flow meter (not shown).
  • the flowmeters are provided, for example, in the outward piping 24 through which the positive electrode electrolyte flows and the outward piping 25 through which the negative electrode electrolyte flows.
  • the flowmeters are provided downstream of the pump 28 ( FIG. 1 ) in the outward piping 24 and downstream of the pump 29 ( FIG. 1 ) in the outward piping 25 .
  • the flow rate of the electrolytic solution can be adjusted by controlling the outputs of the pumps 28 and 29 with the pump controller.
  • the third controller 93 controls the power converter 8 based on the results measured by the flowmeter.
  • the flow rate of the electrolytic solution can also be calculated from the open circuit voltage (OCV) of the monitor cell 61, the temperature of the electrolytic solution, and the outputs of the pumps 28 and 29, for example.
  • OCV open circuit voltage
  • a thermometer for measuring the temperature of the electrolytic solution is provided, for example, at the same position as the flowmeter described above.
  • the third controller 93 sets the variable resistance section 71 to a low resistance value. Therefore, during normal operation of the RF battery system 1, the SOC of the battery cells 10 is controlled within a range expanded from the range of utilization of the main SOC.
  • the third controller 93 sets the variable resistance section 71 to a high resistance value.
  • the resistance value of the variable resistance section 71 is set to a value that makes the difference 10% or more.
  • the controller 9 issues a command to the power conversion device 8 through the first controller 91 so that the SOC of the battery cell 10 is held in a specific state for 10 seconds or more. Specifically, a command is issued to charge or discharge the battery cell 10 for 10 seconds or more in a state where the resistance value is set so as to cause resistance heating in the variable resistance portion 71 .
  • the battery cell 10 is discharged according to the resistance value of the variable resistance section 71 . Due to this discharge, the difference between the SOC on the inlet side and the SOC on the outlet side of the battery cell 10 becomes 10% or more.
  • the SOC of the battery cell 10 is lowered by the third controller 93, so that the SOC of the electrolyte in the battery cell 10 can be brought to a specific state. As a result, the side reactants generated in the battery cells 10 can be redissolved.
  • the RF battery system 1 of Embodiment 2 can set the SOC of the electrolyte in the battery cell 10 to a specific state by arranging the variable resistance unit 71 in the battery cell 10 and controlling the resistance value of the variable resistance unit 71. .
  • the RF battery system 1 of Embodiment 2 can be used by simply modifying equipment used in normal operation of the RF battery system 1 to set the SOC of the electrolyte in the battery cell 10 to a specific state. can. Therefore, in the RF battery system 1 of the second embodiment, compared to the RF battery system 1 of the first embodiment, it is easier to simplify the configuration of the bank 2 .
  • Embodiment 3 describes the above-described third embodiment with reference to FIG. 7 .
  • charging for a short period of time causes the side reactants to be redissolved.
  • a second power supply 72 is connected to the power conversion device 8 .
  • controller 9 comprises a third controller 93 .
  • the second power supply 72 is a power supply different from the power supply 810 (Fig. 1) connected to the power system.
  • Various power storage means such as a secondary battery can be used for the second power supply 72 .
  • the second power supply 72 charges the bank 2 via the power conversion device 8 . This charging changes the SOC of the battery cell 10 .
  • the third controller 93 performs charging so that the difference between the SOC on the inlet side of the electrolyte supplied to the battery cell 10 and the SOC on the outlet side of the electrolyte discharged from the battery cell 10 is 10% or more. to control the power conversion device 8.
  • the difference is 10% or more, the SOC of the electrolyte in the battery cell 10 is in a specific state.
  • the larger the difference the easier it is for the SOC of the electrolyte in the battery cell 10 to reach the specific state.
  • said difference may also be 16% or more, 20% or more, 24% or more, in particular 30% or more.
  • the above difference is 100% or less, further 90% or less, 80% or less, especially 75% or less, 70% or less.
  • the third controller 93 controls the power conversion device 8 so as to perform charging in a short period of time, for example, 10 minutes or less, so that the difference becomes 10% or more.
  • the current density and the flow rate of the electrolytic solution can be appropriately selected so that the side reaction product in the battery cell 10 can be redissolved in a short period of time.
  • the current density is, for example, 300 mA/cm 2 or higher, 400 mA/cm 2 or higher, 500 mA/cm 2 or higher, especially 600 mA/cm 2 or higher.
  • the flow rate of the electrolytic solution is, for example, 4.0 cc/min/cm 2 or less, 3.0 cc/min/cm 2 or less, 2.0 cc/min/cm 2 or less, particularly 0.0 cc/min/cm 2 or less.
  • the electrolyte flow rate is 0.0 cc/min/cm 2 , the electrolyte does not circulate.
  • the flow rate of the electrolytic solution is set to 2.0 cc/min/cm 2 or less, the current density is set to 600 mA/cm 2 or more, and the second power supply 72 is connected to the bank 2 via the power conversion device 8. charging time.
  • the SOC at the outlet side of the electrolyte discharged from the battery cell 10 increases.
  • the third controller 93 controls so as not to charge the bank 2 from the second power supply 72 . Therefore, during normal operation of the RF battery system 1, the SOC of the battery cells 10 is controlled within a range expanded from the range of utilization of the main SOC.
  • the SOC of the battery cell 10 is increased by the third controller 93, so that the SOC of the electrolyte in the battery cell 10 can be brought to a specific state. As a result, the side reactants generated in the battery cells 10 can be redissolved.
  • the RF battery system 1 of Embodiment 3 connects the second power supply 72 to the power conversion device 8, and controls the charging of the bank 2 from the second power supply 72, thereby specifying the SOC of the electrolyte in the battery cell 10. state.
  • the RF battery system 1 of Embodiment 3 can be used by simply modifying equipment used in normal operation of the RF battery system 1 to set the SOC of the electrolyte in the battery cell 10 to a specific state. can.
  • the RF battery system 1 has at least one of the configuration of the first embodiment, the configuration of the second embodiment, and the configuration of the third embodiment.
  • the RF battery system 1 may have all of the configuration of the first embodiment, the configuration of the second embodiment, and the configuration of the third embodiment.
  • Embodiment 4 describes an RF battery system 1 including a plurality of banks 2 with reference to FIG. 8 .
  • the plurality of banks 2 includes a first bank 2a used for normal operation and a second bank 2b used for electrolyte recovery work.
  • the controller 9 comprises a rotation controller 94 .
  • the first bank 2a is a bank that performs charging and discharging between an external power source 810 and a load 820 (Fig. 1).
  • the SOC of the battery cells 10 in the first bank 2a is controlled within an expanded range of the main SOC.
  • the SOC of the electrolyte in the battery cell 10 is substantially the same as the SOC of the cathode electrolyte in the cathode tank 22, and substantially the same as the SOC of the anode electrolyte in the anode tank 23. is the same as
  • the number of first banks 2a is, for example, 2 or more, further 10 or more, particularly 15 or more. The larger the number of first banks 2a, the easier it is for the battery capacity of the entire RF battery system 1 to be secured.
  • the second bank 2b is a bank for recovering the electrolyte.
  • the SOC of the battery cells 10 in the second bank 2b is controlled by the first controller 91 to a specific state. That is, the SOC of the battery cell 10 in the second bank 2b is a state in which the SOC of the electrolyte in the battery cell 10 differs from the SOC of the positive electrode electrolyte in the positive electrode tank 22 by 5% or more, and is held for 10 seconds or more in at least one state in which the SOC of the negative electrode electrolyte in the negative electrode tank 23 differs by 5% or more from the SOC of the negative electrode electrolyte.
  • the number of second banks 2b is less than the number of first banks 2a. For example, the ratio of the number of the second banks 2b to the total number of the plurality of banks 2 is 30% or less, further 20% or less, particularly 10% or less.
  • the number of all banks 2 is, for example, 4 or more. As the number of banks 2 increases, the battery capacity of the entire RF battery system 1 can be increased.
  • the number of banks 2 may be 11 or more, or 16 or more. If the number of banks 2 is large, the entire system becomes huge, and management of the banks 2 becomes complicated.
  • the upper limit of the number of banks 2 is, for example, 100 or less, and further 50 or less.
  • the number of banks 2 is, for example, 11 or more and 100 or less, or 16 or more and 50 or less.
  • the controller 9 controls charging and discharging of each bank 2 independently. Therefore, it is possible to recover the electrolyte in the second bank 2b while charging or discharging the first bank 2a.
  • the controller 9 issues a charging or discharging command to the power conversion device 8 of each first bank 2a.
  • the battery cells 10 are charged or discharged according to the requested charge amount or discharge amount.
  • the controller 9 issues an electrolyte recovery operation command to the power conversion device 8 of the second bank 2b.
  • the battery cells 10 are not charged or discharged between the power source 810 and the load 820 (FIG. 1), and the recovery work of the electrolyte is performed.
  • the SOC of the battery cell 10 is set to a specific state using the means of the first to third embodiments described above.
  • some cells of the cell stack 200 constitute the monitor cell 60, and the circulation paths, valves, and other monitor cells described in the first to third embodiments are omitted.
  • the controller 9 of this example includes a rotation controller 94 .
  • the rotation controller 94 controls the power conversion device 8 so that the states of the battery cells 10 of the plurality of banks 2 are in a specific state in order. In other words, for each of the plurality of banks 2, the rotatable controller 94 selects a time zone for the first bank 2a during normal operation and a time zone for the second bank 2b during the recovery work of the electrolyte. Control the power conversion device 8 to include.
  • the rotation controller 94 for example, when the total number of the plurality of banks 2 is 11, the following control is performed. Let each bank 2 be No. 1, No. 2...No. 11. At a certain time, among the plurality of banks 2, No. 1 to No.
  • the third controller 93 can perform the following controls.
  • the first control when performing the above-described short-time discharge to recover the electrolyte, the third controller 93 charges the first bank 2a with the discharge power of the second bank 2b. may be controlled. In this case, the SOC of the electrolyte in the battery cells 10 of the second bank 2b can be set to a specific state without using the variable resistance section 71 used in the second embodiment.
  • the second control when performing the above-described short-time charging to recover the electrolyte, the third controller 93 charges the second bank 2b with the discharged power of the first bank 2a. may be controlled. In this case, the SOC of the electrolyte in the battery cells 10 of the second bank 2b can be brought to a specific state without using the second power supply 72 used in the third embodiment.
  • the rotation controller 94 allows the second bank 2b to The recovery operation of the electrolyte can be performed with the SOC of the electrolyte in the battery cell 10 set to a specific state. That is, according to the RF battery system 1 of Embodiment 4, the recovery work of the electrolytic solution can be performed without stopping the normal operation of the RF battery system 1 .
  • Test Example 1 In Test Example 1, in a bank in which a side reaction product was generated in a positive electrode cell in a high SOC region, the improvement of the battery performance of the bank was examined by performing an electrolyte recovery operation for redissolving the side reaction product. In this example, an RF battery system with multiple battery cells was tested.
  • Specimen 1-1 is a bank in which a side reaction product is generated in the positive electrode cell in the high SOC region. In the specimen 1-1, the recovery work of the electrolytic solution for redissolving the by-reactants was not performed.
  • ⁇ Test body 1-2> the negative electrode electrolyte is circulated to the positive electrode cell for the bank in which the by-reactant is generated in the positive electrode cell in the high SOC region, and the electrolyte is recovered by re-dissolving the by-reactant. did the work.
  • the circulation of the negative electrode electrolyte to the positive electrode cell is performed by controlling the operation of the first switching unit by the second controller to switch the first positive electrode circulation path and the second negative electrode circulation. (see also Figures 2 and 3). The circulation of the negative electrode electrolyte to the positive electrode cell was performed for 30 seconds.
  • the state of charge of the electrolyte in the battery cell after circulating the reverse polarity electrolyte for 30 seconds was 158% different from the state of charge of the positive electrode electrolyte in the positive electrode tank. That is, in the test sample 1-2, the specific state in which the state of charge of the electrolyte in the battery cell differs from the state of charge of the positive electrode electrolyte in the positive electrode tank by 5% or more was maintained for 10 seconds or longer. The state of charge of the positive electrode electrolyte in the positive electrode tank was 79%.
  • the difference between the state of charge of the electrolyte in the battery cell and the state of charge of the positive electrode electrolyte in the positive electrode tank is the negative electrode electrolyte viewed from the state of charge of the positive electrode electrolyte. It is obtained from the state of charge.
  • test sample 1-3 discharge was performed to the bank in which the side reaction product was generated in the positive electrode cell in the high SOC region, and the recovery work of the electrolytic solution was performed by redissolving the side reaction product.
  • test sample 1-3 as described in Embodiment 4, a plurality of banks were provided, and the banks used for normal operation were charged with the discharge power of the banks in which the recovery work of the electrolyte was performed by the third controller. .
  • the discharge conditions were as follows.
  • the flow rate of the electrolyte circulating in the battery cells is 1.6 cc/min/cm 2 .
  • the current density of the battery cell is 670 mA/cm 2 .
  • the discharge time is 30 seconds.
  • the difference between the state of charge on the inlet side of the electrolyte supplied to the battery cell and the state of charge on the outlet side of the electrolyte discharged from the battery cell is 20%.
  • the state of charge of the electrolyte in the battery cell was 10% different from the state of charge of the positive electrode electrolyte in the positive electrode tank. That is, in the test sample 1-3, the specific state in which the state of charge of the electrolyte in the battery cell differs from the state of charge of the positive electrode electrolyte in the positive electrode tank by 5% or more was maintained for 10 seconds or longer.
  • the state of charge of the positive electrode electrolyte in the positive electrode tank was 79%.
  • the state of charge of the electrolyte in the battery cell is the average value of the state of charge of the electrolyte in the battery cell.
  • ⁇ SOC of battery cell> The bank of each test body was charged, and the SOC of the battery cell was measured when the battery cell was charged to a preset voltage.
  • the charging conditions were as follows.
  • the flow rate of the electrolyte circulating in the battery cells is 1.6 cc/min/cm 2 .
  • the current density of the battery cell is 256 mA/cm 2 .
  • Table 1 shows the results.
  • the SOC of the battery cell when the battery cell is charged to the preset voltage is referred to as "end of charge SOC”.
  • test specimens 1-2 and 1-3 subjected to the recovery work of the electrolyte have a higher battery cell capacity than the test specimen 1-1 which has not been subjected to the recovery work of the electrolyte. It was found that the SOC was improved.
  • Test Specimen 1-2 which was subjected to the electrolyte recovery work of circulating the reverse polarity electrolyte in the positive electrode cell in which the side reaction product was generated, had a battery cell SOC lower than that of Test Specimen 1-1. An improvement of about 10% was found.
  • Test Example 2 In Test Example 2, the discharge time was changed in order to recover the electrolytic solution by discharging the bank in which the side reaction product was generated in the positive electrode cell in the high SOC region and redissolving the side reaction product. . That is, in Test Example 2, the time for which the state of charge of the battery cell is maintained in the specific state was changed.
  • Specimen 2-1 is a bank in which a side reaction product is generated in the positive electrode cell in the high SOC region. The specimen 2-1 was not subjected to the recovery work of the electrolytic solution for redissolving the by-reactants.
  • Test body 2-2, test body 2-3, test body 2-4> In the test specimens 2-2, 2-3, and 2-4, the bank in which the side reaction is generated in the positive electrode cell in the high SOC region is discharged to redissolve the side reaction.
  • the recovery work of the electrolyte was carried out.
  • Each test sample was provided with a plurality of banks as described in the fourth embodiment, and the banks used for normal operation were charged with the discharge power of the banks in which the recovery work of the electrolytic solution was performed by the third controller.
  • the discharge conditions for each specimen were the same except for the discharge time.
  • the flow rate of electrolyte circulating in the battery cells is 0.96 cc/min/cm 2 .
  • the current density of the battery cell is 670 mA/cm 2 .
  • the difference between the state of charge at the inlet side of the electrolyte supplied to the battery cell and the state of charge at the outlet side of the electrolyte discharged from the battery cell is 33%.
  • the discharge time for each specimen was as follows. Specimen 2-2 is 30 seconds. Specimen 2-3 is 60 seconds. Specimens 2-4 are 120 seconds.
  • the state of charge of the electrolyte in the battery cell was different from the state of charge of the positive electrode electrolyte in the positive electrode tank by 16.5%. That is, in the test specimens 2-2, 2-3, and 2-4, the state of charge of the electrolyte in the battery cell is different from the state of charge of the positive electrode electrolyte in the positive electrode tank by 5% or more. was held. In both specimens, the state of charge of the positive electrode electrolyte in the positive electrode tank was 68%.
  • ⁇ SOC of battery cell> The bank of each test body was charged, and the SOC of the battery cell was measured when the battery cell was charged to a preset voltage.
  • the charging conditions were as follows.
  • the flow rate of electrolyte circulating in the battery cells is 0.96 cc/min/cm 2 .
  • the current density of the battery cell is 256 mA/cm 2 .
  • Table 2 shows the results.
  • the SOC of the battery cell when the battery cell is charged to the preset voltage is referred to as "end of charge SOC”.
  • the SOC of the battery cell can be further improved by lengthening the discharge time, that is, by lengthening the time during which the state of charge of the battery cell is held in a specific state.
  • the SOC of the battery cell can be further improved by increasing the discharge time to 30 seconds or longer. It was found that when the discharge time exceeded 60 seconds, the rate of improvement in the SOC of the battery cell was very small. Therefore, even if the discharge time is as short as 10 minutes or less, it can be expected that the side reaction products generated in the battery cells can be redissolved.
  • Test Example 3 In Test Example 3, the difference in SOC was changed in performing the recovery work of the electrolytic solution for redissolving the side reaction by discharging the bank in which the side reaction was generated in the positive electrode cell in the high SOC region. rice field.
  • the difference in SOC is the difference between the state of charge on the inlet side of the electrolyte supplied to the battery cell and the state of charge on the outlet side of the electrolyte discharged from the battery cell. That is, in Test Example 3, the state of charge of the battery cells was changed within the range of the specific state.
  • Specimen 3-1 is a bank in which a side reaction product is generated in the positive electrode cell in the high SOC region. In the specimen 3-1, the recovery work of the electrolytic solution for redissolving the by-reactants was not performed.
  • test body 3-2, test body 3-3, test body 3-4 In test specimens 3-2, 3-3, and 3-4, discharge is performed on the bank in which the side reaction product is generated in the positive electrode cell in the high SOC region, and the side reaction product is redissolved. The recovery work of the electrolyte was carried out. Each test sample was provided with a plurality of banks as described in the fourth embodiment, and the banks used for normal operation were charged with the discharge power of the banks in which the recovery work of the electrolytic solution was performed by the third controller. Table 3 shows the discharge conditions for each specimen. The discharge time was set to 30 seconds for all specimens.
  • the state of charge of the electrolyte in the battery cells was maintained within the specific state range for 10 seconds or longer.
  • the state of charge of the positive electrode electrolyte in the positive electrode tank was 68%.
  • ⁇ SOC of battery cell The bank of each test body was charged, and the SOC of the battery cell was measured when the battery cell was charged to a preset voltage.
  • the charging conditions were as follows.
  • the flow rate of electrolyte circulating in the battery cells is 0.96 cc/min/cm 2 .
  • the current density of the battery cell is 256 mA/cm 2 .
  • Table 3 shows the results.
  • the SOC of the battery cell when the battery cell is charged to the preset voltage is referred to as "end of charge SOC”.
  • the SOC of the battery cells can be further improved by increasing the difference in SOC.
  • the SOC of the battery cells can be further improved when the SOC difference is 30% or more, 33% or more, and further 45% or more. It was found that when the difference in SOC exceeds 48%, the rate of improvement in the SOC of the battery cell becomes very small. Therefore, it can be expected that by discharging so that the difference in SOC is 10% or more and 50% or less, it is possible to re-dissolve the side reaction product generated in the battery cell.
  • Redox flow battery system (RF battery system) 2 bank 2a first bank 2b second bank 10 battery cell 11 diaphragm 12 positive electrode cell 13 negative electrode cell 14 positive electrode 15 negative electrode 22 positive electrode tank 23 negative electrode tank 24, 25 outbound pipe 26, 27 return route Piping 28, 29 Pump 31 First positive electrode circulation path 32 Second positive electrode circulation path 33, 33a, 33b Main outward piping 34a, 34b Branch outward piping 35, 35a, 35b Main return piping 36a, 36b Branch return piping 37a, 37b, 38a, 38b valves 39a, 39b common outward piping, 39c, 39d common return piping 390a, 390b three-way valve, 390c, 390d three-way valve 41 first negative electrode circulation path 42 second negative electrode circulation path 43, 43a , 43b main outbound pipe 44a, 44b branch outbound pipe 45, 45a, 45b main return pipe 46a, 46b branch return pipe 47a, 47b, 48a, 48b valve 60, 61 monitor cell 71 variable resistor 72 second power supply 8

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Abstract

This redox flow battery system comprises a bank, and a controller that controls the charge status of the bank. The bank is provided with a battery cell, a positive-electrode tank in which anolyte that circulates in the battery cell is stored, a negative-electrode tank in which a catholyte that circulates in the battery cell is stored, and a power conversion device that controls charging and discharging of the battery cell. The controller is provided with a first controller that controls the power conversion device so as to maintain the charge status of the battery cell in a specific state for at least ten seconds. The specific state is at least one of a first state and a second state, the first state being a state in which the charge status of the electrolyte inside the battery cell differs from the charge status of the anolyte inside the positive-electrode tank by at least 5%, and the second state being a state in which the charge status of the electrolyte in the battery cell differs from the charge status of the catholyte inside the negative-electrode tank by at least 5%.

Description

レドックスフロー電池システムRedox flow battery system
　本開示は、レドックスフロー電池システムに関する。
　本出願は、２０２１年６月２１日付の日本国出願の特願２０２１－１０２３００に基づく優先権を主張し、前記日本国出願に記載された全ての記載内容を援用するものである。 The present disclosure relates to redox flow battery systems.
This application claims priority based on Japanese Patent Application No. 2021-102300 filed in Japan on June 21, 2021, and incorporates all the content described in the Japanese application.
　特許文献１は、マンガンイオンを含有する正極電解液と、チタンイオンを含有する負極電解液とを用いたマンガン－チタン系のレドックスフロー電池を開示する。正極電解液にマンガンイオンが含まれていると、充電及び放電に伴ってマンガン酸化物（ＭｎＯ２）が析出し得る。特許文献１は、正極電解液中にマンガンイオンに加えてチタンイオンを含有することで、マンガン酸化物の析出を抑制している。 Patent Document 1 discloses a manganese-titanium redox flow battery using a positive electrode electrolyte containing manganese ions and a negative electrode electrolyte containing titanium ions. If manganese ions are contained in the positive electrode electrolyte, manganese oxide (MnO 2 ) may precipitate during charging and discharging. Patent document 1 suppresses deposition of manganese oxide by containing titanium ions in addition to manganese ions in the positive electrode electrolyte.
国際公開第２０１１／１１１２５４号WO2011/111254
　本開示のレドックスフロー電池システムは、
　バンクと、
　前記バンクの充電状態を制御する制御器と、を備え、
　前記バンクは、
　　電池セルと、
　　前記電池セルに循環される正極電解液が貯留された正極タンクと、
　　前記電池セルに循環される負極電解液が貯留された負極タンクと、
　　前記電池セルの充電及び放電を制御する電力変換装置とを備え、
　前記制御器は、前記電池セルの充電状態が特定状態で１０秒以上保持されるように前記電力変換装置を制御する第一制御器を備え、
　前記特定状態は、第一状態及び第二状態の少なくとも一方の状態であり、
　前記第一状態は、前記電池セル内の電解液の充電状態が前記正極タンク内の正極電解液の充電状態と５％以上異なる状態であり、
　前記第二状態は、前記電池セル内の電解液の充電状態が前記負極タンク内の負極電解液の充電状態と５％以上異なる状態である。 The redox flow battery system of the present disclosure comprises
bank and
a controller that controls the state of charge of the bank;
The bank is
a battery cell;
a positive electrode tank in which a positive electrode electrolyte circulating in the battery cell is stored;
a negative electrode tank in which a negative electrode electrolyte circulating in the battery cell is stored;
A power conversion device that controls charging and discharging of the battery cell,
The controller comprises a first controller that controls the power conversion device so that the state of charge of the battery cell is held in a specific state for 10 seconds or more,
The specific state is at least one of a first state and a second state,
The first state is a state in which the state of charge of the electrolyte in the battery cell differs from the state of charge of the positive electrode electrolyte in the positive electrode tank by 5% or more,
The second state is a state in which the charge state of the electrolyte in the battery cell differs from the charge state of the negative electrode electrolyte in the negative electrode tank by 5% or more.
図１は、実施形態のレドックスフロー電池システムの基本構成を示す概略構成図である。FIG. 1 is a schematic configuration diagram showing the basic configuration of the redox flow battery system of the embodiment. 図２は、実施形態１－１のレドックスフロー電池システムにおける通常運転時の状態を示す概略構成図である。FIG. 2 is a schematic configuration diagram showing a state during normal operation in the redox flow battery system of Embodiment 1-1. 図３は、実施形態１－１のレドックスフロー電池システムにおける電解液の回復作業時の状態を示す概略構成図である。FIG. 3 is a schematic configuration diagram showing the state of the redox flow battery system of Embodiment 1-1 during recovery work of the electrolytic solution. 図４は、実施形態１－２のレドックスフロー電池システムにおける通常運転時の状態を示す概略構成図である。FIG. 4 is a schematic configuration diagram showing a state during normal operation in the redox flow battery system of Embodiment 1-2. 図５は、実施形態１－２のレドックスフロー電池システムにおける電解液の回復作業時の状態を示す概略構成図である。FIG. 5 is a schematic diagram showing the state of the redox flow battery system of Embodiment 1-2 during recovery work of the electrolytic solution. 図６は、実施形態２のレドックスフロー電池システムの構成を示す概略構成図である。FIG. 6 is a schematic configuration diagram showing the configuration of the redox flow battery system of Embodiment 2. FIG. 図７は、実施形態３のレドックスフロー電池システムの構成を示す概略構成図である。FIG. 7 is a schematic configuration diagram showing the configuration of the redox flow battery system of Embodiment 3. FIG. 図８は、実施形態４のレドックスフロー電池システムの構成を示す概略構成図である。FIG. 8 is a schematic configuration diagram showing the configuration of the redox flow battery system of Embodiment 4. FIG.
　［本開示が解決しようとする課題］
　レドックスフロー電池システムにおいて、エネルギー密度を高めることが求められている。エネルギー密度を高めることができれば、電池容量を増やすことが可能である。レドックスフロー電池のエネルギー密度を高める手段の一つは、電解液の充電状態（ＳＯＣ：Ｓｔａｔｅ　Ｏｆ　Ｃｈａｒｇｅ）の利用範囲を拡大することである。しかし、ＳＯＣの利用範囲の拡大に伴って、レドックスフロー電池を構成する電池セル内では、酸化物が析出するといった副反応が生じ易くなる。電池セル内で生成した副反応物は、例えば電極に付着する。電極に副反応物が付着すると、電極の性能が低下し、電池性能に悪影響を及ぼす。 [Problems to be Solved by the Present Disclosure]
Redox flow battery systems are required to have higher energy densities. If the energy density can be increased, the battery capacity can be increased. One of the means to increase the energy density of the redox flow battery is to expand the range of utilization of the state of charge (SOC) of the electrolyte. However, with the expansion of the range of utilization of SOC, side reactions such as deposition of oxides are likely to occur within the battery cells constituting the redox flow battery. A by-reactant generated in the battery cell adheres to the electrode, for example. Adhesion of the by-reactants to the electrode reduces the performance of the electrode and adversely affects the battery performance.
　本開示は、高エネルギー密度を実現できながら、副反応による電池性能の低下を改善できるレドックスフロー電池システムを提供することを目的の一つとする。 One of the purposes of the present disclosure is to provide a redox flow battery system that can improve battery performance degradation due to side reactions while achieving high energy density.
　［本開示の効果］
　本開示のレドックスフロー電池システムは、高エネルギー密度を実現できながら、副反応による電池性能の低下を改善できる。 [Effect of the present disclosure]
The redox flow battery system of the present disclosure can improve battery performance degradation due to side reactions while achieving high energy density.
　［本開示の実施形態の説明］
　最初に本開示の実施態様を列記して説明する。 [Description of Embodiments of the Present Disclosure]
First, the embodiments of the present disclosure are listed and described.
　（１）本開示の一態様に係るレドックスフロー電池システムは、
　バンクと、
　前記バンクの充電状態を制御する制御器と、を備え、
　前記バンクは、
　　電池セルと、
　　前記電池セルに循環される正極電解液が貯留された正極タンクと、
　　前記電池セルに循環される負極電解液が貯留された負極タンクと、
　　前記電池セルの充電及び放電を制御する電力変換装置とを備え、
　前記制御器は、前記電池セルの充電状態が特定状態で１０秒以上保持されるように前記電力変換装置を制御する第一制御器を備え、
　前記特定状態は、第一状態及び第二状態の少なくとも一方の状態であり、
　前記第一状態は、前記電池セル内の電解液の充電状態が前記正極タンク内の正極電解液の充電状態と５％以上異なる状態であり、
　前記第二状態は、前記電池セル内の電解液の充電状態が前記負極タンク内の負極電解液の充電状態と５％以上異なる状態である。 (1) A redox flow battery system according to one aspect of the present disclosure,
bank and
a controller that controls the state of charge of the bank;
The bank is
a battery cell;
a positive electrode tank in which a positive electrode electrolyte circulating in the battery cell is stored;
a negative electrode tank in which a negative electrode electrolyte circulating in the battery cell is stored;
A power conversion device that controls charging and discharging of the battery cell,
The controller comprises a first controller that controls the power conversion device so that the state of charge of the battery cell is held in a specific state for 10 seconds or more,
The specific state is at least one of a first state and a second state,
The first state is a state in which the state of charge of the electrolyte in the battery cell differs from the state of charge of the positive electrode electrolyte in the positive electrode tank by 5% or more,
The second state is a state in which the charge state of the electrolyte in the battery cell differs from the charge state of the negative electrode electrolyte in the negative electrode tank by 5% or more.
　本開示のレドックスフロー電池システムは、電池セルの充電状態が特定状態で１０秒以上保持されることで、電池セル内で生成した副反応物を再溶解することができる。電解液の充電状態の利用範囲を拡大すると、上述したように、電池セル内で副反応物が生成され易い。本開示のレドックスフロー電池システムは、電池セル内で副反応物が生成されたとしても、その副反応物を再溶解して、電極の性能を回復させることができる。本開示のレドックスフロー電池システムは、副反応物を再溶解するといった電解液の回復作業が可能であることから、電解液の充電状態の利用範囲を拡大することができる。以上より、本開示のレドックスフロー電池システムは、高エネルギー密度を実現できながら、副反応による電池性能の低下を改善できる。 In the redox flow battery system of the present disclosure, the charged state of the battery cells is maintained in a specific state for 10 seconds or longer, thereby redissolving the by-reactants generated in the battery cells. As described above, if the range of utilization of the state of charge of the electrolytic solution is expanded, side reaction products are likely to be generated in the battery cells. The redox flow battery system of the present disclosure can re-dissolve the side-reactant even if the side-reactant is generated in the battery cell to restore the performance of the electrode. Since the redox flow battery system of the present disclosure is capable of recovering the electrolytic solution by redissolving the by-reactant, it is possible to expand the usage range of the state of charge of the electrolytic solution. As described above, the redox flow battery system of the present disclosure can improve battery performance degradation due to side reactions while achieving high energy density.
　副反応物を再溶解するとの上記記載は、広義には、特定のＳＯＣ範囲での充電又は放電によって電解液の状態が変化したものを、元の状態に戻すこととして定義される。この定義は、固体の析出物を電解液中でイオンに戻すことだけに限られない。この定義には、気体・固体・液体の相変化を伴うことも、伴わないことも含まれる。また、亜鉛等の固体の活物質を含む電解液である場合は、その電析量を制御することも含まれる。副反応によって電極の表面に活物質が析出することがある。副反応による析出物が電極に付着すると、電極の反応性が劣化する。つまり、電池性能が低下する。電極の反応性を向上させる目的で、電極の表面に触媒等を付着させることもある。副反応による析出物が触媒等を覆うように析出しても、電池性能の低下を招く。電極の表面に付着した析出物を再溶解することで、電極の表面の状態を維持することができる。これにより、電池性能の低下を抑制できる。 The above description of redissolving the side reaction product is broadly defined as restoring the state of the electrolytic solution, which has changed due to charging or discharging within a specific SOC range, to its original state. This definition is not limited to converting solid deposits back into ions in the electrolyte. This definition includes with or without a gas/solid/liquid phase change. In the case of an electrolytic solution containing a solid active material such as zinc, it also includes controlling the amount of electrodeposition. An active material may deposit on the surface of an electrode by a side reaction. When deposits from side reactions adhere to the electrode, the reactivity of the electrode deteriorates. That is, the battery performance is degraded. For the purpose of improving the reactivity of the electrode, a catalyst or the like may be adhered to the surface of the electrode. Even if the deposit due to the side reaction deposits so as to cover the catalyst and the like, the performance of the battery is lowered. By re-dissolving the precipitate adhering to the surface of the electrode, the condition of the surface of the electrode can be maintained. Thereby, deterioration of battery performance can be suppressed.
　（２）本開示のレドックスフロー電池システムにおいて、前記特定状態が１０分以下保持されてもよい。 (2) In the redox flow battery system of the present disclosure, the specific state may be maintained for 10 minutes or less.
　通常運転時での充電又は放電では、電池セルの充電状態が特定状態で１０秒以上保持され難い。通常運転時での充電又は放電とは、電解液の充電状態の利用範囲を後述するメインＳＯＣの利用範囲よりも拡大して、レドックスフロー電池システムが外部の電源や負荷につながる電力系統に対して行う充電又は放電のことである。特定状態とするためには、レドックスフロー電池システムの通常運転を停止する等、運転に制約が生じ得る。特定状態に保持される時間が１０分以下という短時間であれば、電池セル内で生成した副反応物を再溶解できると共に、レドックスフロー電池システムの通常運転に及ぼす影響が短時間に抑えられる。 When charging or discharging during normal operation, it is difficult to maintain the charged state of the battery cells in a specific state for 10 seconds or more. Charging or discharging during normal operation means expanding the usage range of the state of charge of the electrolyte beyond the usage range of the main SOC, which will be described later, so that the redox flow battery system is connected to an external power source or load. It is the charging or discharging that occurs. In order to bring about the specific state, the operation may be restricted, such as stopping the normal operation of the redox flow battery system. If the specific state is maintained for a short period of time of 10 minutes or less, the by-reactants generated in the battery cells can be redissolved, and the effects on the normal operation of the redox flow battery system can be suppressed in a short period of time.
　（３）本開示のレドックスフロー電池システムにおいて、
　前記電池セルは、正極セルと負極セルとを備え、
　前記正極電解液を前記正極タンクから前記正極セルを介して前記正極タンクに戻す第一の正極循環路と、
　前記負極電解液を前記負極タンクから前記負極セルを介して前記負極タンクに戻す第一の負極循環路と、
　前記正極電解液を前記正極タンクから前記負極セルを介して前記正極タンクに戻す第二の正極循環路及び前記負極電解液を前記負極タンクから前記正極セルを介して前記負極タンクに戻す第二の負極循環路の少なくとも一方の循環路と、
　前記第一の正極循環路と前記第二の負極循環路とを切り替える第一切替部及び前記第一の負極循環路と前記第二の正極循環路とを切り替える第二切替部の少なくとも一方の切替部とを有し、
　前記制御器は、前記第一切替部又は前記第二切替部の動作を制御する第二制御器を備えてもよい。 (3) In the redox flow battery system of the present disclosure,
The battery cell includes a positive electrode cell and a negative electrode cell,
a first positive electrode circuit for returning the positive electrode electrolyte from the positive electrode tank to the positive electrode tank through the positive electrode cell;
a first negative electrode circulation path returning the negative electrode electrolyte from the negative electrode tank to the negative electrode tank through the negative electrode cell;
a second positive electrode circuit for returning the positive electrode electrolyte from the positive electrode tank to the positive electrode tank via the negative electrode cell; and a second positive electrode circuit for returning the negative electrode electrolyte from the negative electrode tank to the negative electrode tank via the positive electrode cell. at least one of the negative electrode circuits;
Switching of at least one of a first switching unit for switching between the first positive electrode circuit and the second negative electrode circuit and a second switching unit for switching between the first negative electrode circuit and the second positive electrode circuit and
The controller may include a second controller that controls the operation of the first switching section or the second switching section.
　レドックスフロー電池システムの通常運転時は、第一の正極循環路によって正極セルに正極電解液が循環され、第一の負極循環路によって負極セルに負極電解液が循環される。第二制御器によって切替部の動作が制御されると、正極セル又は負極セルに逆極性の電解液が循環される。第一切替部によって第一の正極循環路と第二の負極循環路とが切り替えられると、第二の負極循環路によって正極セルに負極電解液が循環される。第二切替部によって第一の負極循環路と第二の正極循環路とが切り替えられると、第二の正極循環路によって負極セルに正極電解液が循環される。正極セル又は負極セルに逆極性の電解液が循環されることで、電池セル内の電解液の充電状態を特定状態にできる。 During normal operation of the redox flow battery system, the first positive electrode circuit circulates the positive electrode electrolyte to the positive electrode cell, and the first negative electrode circuit circulates the negative electrode electrolyte to the negative electrode cell. When the operation of the switching unit is controlled by the second controller, the electrolyte solution of opposite polarity is circulated through the positive electrode cell or the negative electrode cell. When the first switching unit switches between the first positive electrode circuit and the second negative electrode circuit, the second negative electrode circuit circulates the negative electrode electrolyte in the positive electrode cell. When the second switching unit switches between the first negative electrode circuit and the second positive electrode circuit, the second positive electrode circuit circulates the positive electrode electrolyte in the negative electrode cell. By circulating the electrolyte of opposite polarity in the positive electrode cell or the negative electrode cell, the state of charge of the electrolyte in the battery cell can be set to a specific state.
　（４）本開示のレドックスフロー電池システムにおいて、
　前記制御器は、前記電池セルに供給される電解液の入口側の充電状態と、前記電池セルから排出される前記電解液の出口側の充電状態との差が１０％以上となる充電又は放電を行うように前記電力変換装置を制御する第三制御器を備えてもよい。 (4) In the redox flow battery system of the present disclosure,
The controller performs charging or discharging such that the difference between the charged state at the inlet side of the electrolyte supplied to the battery cell and the charged state at the outlet side of the electrolyte discharged from the battery cell is 10% or more. A third controller may be provided that controls the power conversion device to perform
　制御器が第三制御器を備えると、レドックスフロー電池システムの通常運転で使用される設備をそのまま利用する、又は上記設備に簡易な改変を施して利用することで、電池セル内の電解液の充電状態を特定状態にできる。 When the controller is equipped with a third controller, the equipment used in the normal operation of the redox flow battery system can be used as it is, or the above equipment can be used with a simple modification to reduce the amount of electrolyte in the battery cell. The charging state can be set to a specific state.
　（５）本開示のレドックスフロー電池システムにおいて、前記第三制御器は、３００ｍＡ／ｃｍ２以上の電流密度で前記充電又は前記放電を行うように前記電力変換装置を制御してもよい。 (5) In the redox flow battery system of the present disclosure, the third controller may control the power converter so that the charging or discharging is performed at a current density of 300 mA/cm 2 or higher.
　３００ｍＡ／ｃｍ２以上の電流密度での充電又は放電は、電池セル内の電解液の充電状態を特定状態にし易い。 Charging or discharging at a current density of 300 mA/cm 2 or higher tends to bring the state of charge of the electrolyte in the battery cell into a specific state.
　（６）本開示のレドックスフロー電池システムにおいて、前記第三制御器は、前記電池セルに供給される前記電解液の流量が４．０ｃｃ／ｍｉｎ／ｃｍ２以下であるときに前記充電又は前記放電を行うように前記電力変換装置を制御してもよい。 (6) In the redox flow battery system of the present disclosure, the third controller controls the charging or discharging when the flow rate of the electrolytic solution supplied to the battery cell is 4.0 cc/min/cm 2 or less. You may control the said power converter to perform.
　電池セルに供給される電解液の流量が４．０ｃｃ／ｍｉｎ／ｃｍ２以下であるときの充電又は放電は、電池セル内の電解液の充電状態を特定状態にし易い。 Charging or discharging when the flow rate of the electrolyte supplied to the battery cells is 4.0 cc/min/cm 2 or less tends to bring the state of charge of the electrolyte in the battery cells to a specific state.
　（７）本開示のレドックスフロー電池システムにおいて、
　前記第一状態は、前記電池セル内の電解液の充電状態が前記正極タンク内の正極電解液の充電状態と１５％以上異なる状態であり、
　前記第二状態は、前記電池セル内の電解液の充電状態が前記負極タンク内の負極電解液の充電状態と１５％以上異なる状態であってもよい。 (7) In the redox flow battery system of the present disclosure,
The first state is a state in which the state of charge of the electrolyte in the battery cell differs from the state of charge of the positive electrode electrolyte in the positive electrode tank by 15% or more,
The second state may be a state in which the charge state of the electrolyte in the battery cell differs from the charge state of the negative electrode electrolyte in the negative electrode tank by 15% or more.
　（７）の構成によれば、電池セル内で生成した副反応物をより効果的に再溶解することができる。 According to the configuration of (7), it is possible to more effectively re-dissolve the side reaction products generated in the battery cells.
　（８）本開示のレドックスフロー電池システムにおいて、
　前記バンクは複数設けられており、
　前記制御器は、前記複数のバンクの各々に備わる前記電池セルの充電状態が前記複数のバンク間で順番に前記特定状態となるように前記複数のバンクの各々に備わる前記電力変換装置を制御する輪番制御器を備えてもよい。 (8) In the redox flow battery system of the present disclosure,
A plurality of the banks are provided,
The controller controls the power conversion device provided in each of the plurality of banks so that the state of charge of the battery cells provided in each of the plurality of banks sequentially becomes the specific state among the plurality of banks. A rotating controller may be provided.
　特定状態とするためには、レドックスフロー電池システムの通常運転を停止する等、運転に制約が生じ得る。制御器が輪番制御器を備えると、輪番制御器によって各バンクの電池セルをバンク間で順番に特定状態にできる。具体的には、電池セル内の電解液の回復作業を行うバンクでは、電池セル内の電解液の充電状態を特定状態にできる。一方、電池セル内の電解液の回復作業を行わないバンクでは、電池セル内の電解液の充電状態を通常運転時の状態にできる。つまり、輪番制御器により、レドックスフロー電池システムの通常運転を停止することなく、電池セル内の電解液の回復作業を行うことができる。 　In order to achieve a specific state, there may be restrictions on operation, such as stopping normal operation of the redox flow battery system. If the controller includes a rotatable controller, the rotatable controller can cause the battery cells in each bank to be placed in a particular state in sequence from bank to bank. Specifically, in the bank where the recovery work of the electrolyte in the battery cell is performed, the state of charge of the electrolyte in the battery cell can be set to a specific state. On the other hand, in the bank in which the recovery work of the electrolyte in the battery cell is not performed, the state of charge of the electrolyte in the battery cell can be brought to the state of normal operation. In other words, the rotatable controller enables recovery of the electrolyte in the battery cells without stopping the normal operation of the redox flow battery system.
　［本開示の実施形態の詳細］
　本開示のレドックスフロー電池システムの具体例を、図面を参照して説明する。以下、レドックスフロー電池を「ＲＦ電池」と呼ぶ場合がある。また、充電状態を「ＳＯＣ」と呼ぶ場合がある。図中の同一符号は同一又は相当部分を示す。なお、本発明はこれらの例示に限定されるものではなく、請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 [Details of the embodiment of the present disclosure]
A specific example of the redox flow battery system of the present disclosure will be described with reference to the drawings. Hereinafter, the redox flow battery may be referred to as "RF battery". Also, the state of charge may be referred to as "SOC". The same reference numerals in the drawings indicate the same or corresponding parts. The present invention is not limited to these exemplifications, but is indicated by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.
　＜ＲＦ電池システムの概要＞
　実施形態のＲＦ電池システム１は、図１に示すように、バンク２と、バンク２のＳＯＣを制御する制御器９とを備える。バンク２は、電池セル１０と、正極タンク２２と、負極タンク２３と、電力変換装置８とを備える。バンク２は、一つ又は複数設けられている。図１に示すバンク２は一つである。複数のバンク２が設けられている場合、複数のバンク２の各々が、電池セル１０と、正極タンク２２と、負極タンク２３と、電力変換装置８とを備える。実施形態のＲＦ電池システム１の特徴の一つは、制御器９が第一制御器９１を備える点にある。第一制御器９１は、電池セル１０のＳＯＣが特定状態で１０秒以上保持されるように電力変換装置８を制御する。特定状態は、第一状態及び第二状態の少なくとも一方の状態である。第一状態は、電池セル１０内の電解液のＳＯＣが正極タンク２２内の正極電解液のＳＯＣと５％以上異なる状態である。第二状態は、電池セル１０内の電解液のＳＯＣが負極タンク２３内の負極電解液のＳＯＣと５％以上異なる状態である。以下では、まずＲＦ電池システム１の基本構成を説明し、その後に電池セル１０のＳＯＣ、及び電池セル１０のＳＯＣを特定状態とする手段を説明する。 <Overview of RF battery system>
The RF battery system 1 of the embodiment includes a bank 2 and a controller 9 that controls the SOC of the bank 2, as shown in FIG. Bank 2 includes battery cells 10 , positive electrode tank 22 , negative electrode tank 23 , and power conversion device 8 . One or a plurality of banks 2 are provided. There is one bank 2 shown in FIG. When multiple banks 2 are provided, each of the multiple banks 2 includes a battery cell 10 , a positive electrode tank 22 , a negative electrode tank 23 , and a power conversion device 8 . One of the features of the RF battery system 1 of the embodiment is that the controller 9 has a first controller 91 . The first controller 91 controls the power conversion device 8 so that the SOC of the battery cell 10 is held in a specific state for 10 seconds or longer. The specific state is at least one of the first state and the second state. The first state is a state in which the SOC of the electrolyte in the battery cell 10 differs from the SOC of the cathode electrolyte in the cathode tank 22 by 5% or more. The second state is a state in which the SOC of the electrolyte in the battery cell 10 differs from the SOC of the anode electrolyte in the anode tank 23 by 5% or more. Below, the basic configuration of the RF battery system 1 will be described first, and then the SOC of the battery cell 10 and means for setting the SOC of the battery cell 10 to a specific state will be described.
　＜ＲＦ電池システムの基本構成＞
　図１を参照して、ＲＦ電池システム１の基本構成を説明する。ＲＦ電池システム１は、代表的には、変電設備８００を介して、外部の電源８１０と負荷８２０とに接続される。ＲＦ電池システム１は、電源８１０から供給された電力を充電したり、充電した電力を負荷８２０に放電したりすることが可能である。電源８１０は、例えば、太陽光発電や風力発電等の自然エネルギーを利用した発電設備、又はその他一般の発電所である。負荷８２０は、例えば、電力系統、又は電力の需要家である。ＲＦ電池システム１は、例えば、負荷平準化用途、瞬低補償、非常用電源等の用途、自然エネルギー発電の出力平滑化用途に利用される。ここでは、電源８１０や負荷８２０につながる電力系統に対して充電又は放電を行うにあたり、電解液の充電状態の利用範囲を後述するメインＳＯＣの利用範囲にサブＳＯＣの利用範囲を加えた範囲にまで拡大して充電又は放電を行うＲＦ電池システム１の運転を通常運転と呼ぶ。 <Basic configuration of RF battery system>
The basic configuration of the RF battery system 1 will be described with reference to FIG. The RF battery system 1 is typically connected to an external power supply 810 and load 820 via a substation facility 800 . The RF battery system 1 can charge power supplied from the power supply 810 and discharge the charged power to the load 820 . The power source 810 is, for example, power generation equipment using natural energy such as solar power generation or wind power generation, or other general power plants. The load 820 is, for example, a power system or a power consumer. The RF battery system 1 is used, for example, for load leveling, momentary sag compensation, emergency power supply, and output smoothing of natural energy power generation. Here, when charging or discharging the electric power system connected to the power supply 810 and the load 820, the range of utilization of the state of charge of the electrolytic solution is expanded to the range of utilization of the main SOC, which will be described later, plus the range of utilization of the sub-SOC. The operation of the RF battery system 1 that is expanded and charged or discharged is called normal operation.
　〔バンク〕
　バンク２は、電力系統に対して充電又は放電を行う二次電池の単位システムである。バンク２は、電池セル１０と、電池セル１０に電解液を循環させる循環機構と、電池セル１０の充電及び放電を制御する電力変換装置８とを備える。バンク２は、電池セル１０に電解液を循環させることで、充電又は放電を行う。複数のバンク２が設けられている場合、各バンク２の電池セル１０の充電及び放電は各電力変換装置８によって独立して制御されている。 〔bank〕
Bank 2 is a secondary battery unit system that charges or discharges a power system. The bank 2 includes battery cells 10 , a circulation mechanism that circulates an electrolytic solution in the battery cells 10 , and a power converter 8 that controls charging and discharging of the battery cells 10 . The bank 2 is charged or discharged by circulating the electrolyte in the battery cells 10 . When a plurality of banks 2 are provided, charging and discharging of the battery cells 10 of each bank 2 are independently controlled by each power conversion device 8 .
　〈電池セル〉
　電池セル１０は、隔膜１１で正極セル１２と負極セル１３とに分離されている。正極セル１２には、正極電極１４が内蔵されている。正極セル１２には、正極電解液が供給される。負極セル１３には、負極電極１５が内蔵されている。負極セルに１３には、負極電解液が供給される。 <Battery cell>
A battery cell 10 is separated into a positive electrode cell 12 and a negative electrode cell 13 by a diaphragm 11 . A positive electrode 14 is incorporated in the positive electrode cell 12 . A positive electrode electrolyte is supplied to the positive electrode cell 12 . A negative electrode 15 is incorporated in the negative electrode cell 13 . A negative electrode electrolyte is supplied to the negative electrode cell 13 .
　電池セル１０は、代表的には、複数の電池セル１０が積層されたセルスタック２００と呼ばれる形態で利用されている。セルスタック２００は、あるセルフレーム１００、正極電極１４、隔膜１１、負極電極１５、別のセルフレーム１００が繰り返し積層された積層体と、積層体を挟む二つのエンドプレート２０１と、締付部材２０２とを備える。締付部材２０２は、例えば長ボルト及びナットである。二つのエンドプレート２０１は、締付部材２０２によって締め付けられている。この締め付けによって、上記積層体の積層状態が保持される。セルスタック２００は、代表的には、所定数の電池セル１０をサブスタック（図示せず）とし、複数のサブスタックを積層した形態で利用されている。サブスタックやセルスタック２００における電池セル１０の積層方向の両端に位置するセルフレーム１００の外側には、給排板（図示せず）が配置されている。 The battery cells 10 are typically used in a form called a cell stack 200 in which a plurality of battery cells 10 are stacked. The cell stack 200 includes a cell frame 100, a positive electrode 14, a diaphragm 11, a negative electrode 15, and another cell frame 100, which are repeatedly stacked, two end plates 201 sandwiching the stack, and a fastening member 202. and The tightening member 202 is, for example, a long bolt and nut. The two end plates 201 are clamped by clamping members 202 . By this tightening, the laminated state of the laminated body is maintained. The cell stack 200 is typically used in a form in which a predetermined number of battery cells 10 are used as substacks (not shown), and a plurality of substacks are stacked. Supply/discharge plates (not shown) are arranged outside the cell frames 100 positioned at both ends in the stacking direction of the battery cells 10 in the sub-stack or cell stack 200 .
　セルフレーム１００は、枠体１１０と双極板１１２とを備える。枠体１１０は、双極板１１２の外周に設けられている。枠体１１０の内側には、双極板１１２を挟んで正極電極１４と負極電極１５とが収納されている。隣り合うセルフレーム１００の双極板１１２の間に、隔膜１１を挟んで正極電極１４及び負極電極１５が配置されることにより、１つの電池セル１０が構成されている。枠体１１０の間には、電池セル１０から電解液が漏洩することを抑制するためにシール部材１５０が配置されている。 The cell frame 100 includes a frame 110 and a bipolar plate 112. Frame 110 is provided on the outer periphery of bipolar plate 112 . A positive electrode 14 and a negative electrode 15 are housed inside the frame 110 with a bipolar plate 112 interposed therebetween. One battery cell 10 is configured by arranging the positive electrode 14 and the negative electrode 15 between the bipolar plates 112 of the adjacent cell frames 100 with the diaphragm 11 interposed therebetween. A sealing member 150 is arranged between the frames 110 to prevent the electrolyte from leaking from the battery cells 10 .
　〈循環機構〉
　循環機構は、正極セル１２に正極電解液を循環させる正極循環機構と、負極セル１３に負極電解液を循環させる負極循環機構とを備える。正極循環機構は、正極タンク２２と、往路配管２４と、復路配管２６と、ポンプ２８とを備える。正極タンク２２には、正極電解液が貯留されている。往路配管２４及び復路配管２６は、正極タンク２２と正極セル１２との間をつなぐ。ポンプ２８は、供給側の往路配管２４に設けられている。負極循環機構は、負極タンク２３と、往路配管２５と、復路配管２７と、ポンプ２９とを備える。負極タンク２３には、負極電解液が貯留されている。往路配管２５及び復路配管２７は、負極タンク２３と負極セル１３との間をつなぐ。ポンプ２９は、供給側の往路配管２５に設けられている。 <Circulation mechanism>
The circulation mechanism includes a positive electrode circulation mechanism that circulates the positive electrode electrolyte in the positive electrode cells 12 and a negative electrode circulation mechanism that circulates the negative electrode electrolyte in the negative electrode cells 13 . The positive electrode circulation mechanism includes a positive electrode tank 22 , an outward pipe 24 , a return pipe 26 and a pump 28 . A positive electrode electrolyte is stored in the positive electrode tank 22 . Outbound pipe 24 and return pipe 26 connect between positive electrode tank 22 and positive electrode cell 12 . A pump 28 is provided in the forward line 24 on the supply side. The negative electrode circulation mechanism includes a negative electrode tank 23 , an outward pipe 25 , a return pipe 27 and a pump 29 . A negative electrode electrolyte is stored in the negative electrode tank 23 . Outbound pipe 25 and return pipe 27 connect between negative electrode tank 23 and negative electrode cell 13 . The pump 29 is provided in the outward line pipe 25 on the supply side.
　正極電解液は、正極タンク２２から往路配管２４を通って正極セル１２に供給され、正極セル１２から復路配管２６を通って正極タンク２２に戻される。負極電解液は、負極タンク２３から往路配管２５を通って負極セル１３に供給され、負極セル１３から復路配管２７を通って負極タンク２３に戻される。正極セル１２に正極電解液が循環されると共に、負極セル１３に負極電解液が循環されることで、電池セル１０は、各極の電解液中の活物質イオンの価数変化反応に伴って充電及び放電を行う。 The positive electrode electrolyte is supplied from the positive electrode tank 22 to the positive electrode cell 12 through the outbound pipe 24 and returned from the positive electrode cell 12 to the positive electrode tank 22 through the return pipe 26 . The negative electrode electrolyte is supplied from the negative electrode tank 23 to the negative electrode cell 13 through the forward pipe 25 and returned from the negative electrode cell 13 to the negative electrode tank 23 through the return pipe 27 . By circulating the positive electrode electrolyte solution in the positive electrode cell 12 and circulating the negative electrode electrolyte solution in the negative electrode cell 13, the battery cell 10 can be changed according to the valence change reaction of the active material ions in the electrolyte solution of each electrode. Charge and discharge.
　〈電解液〉
　電解液は、活物質イオンを含む溶液である。活物質イオンは、活物質として機能するイオンである。活物質イオンは、代表的には、酸化還元により価数が変化する金属イオンである。活物質イオンは、例えば、マンガン、バナジウム、鉄、クロム、チタン、及び亜鉛からなる群より選択される元素のイオンである。 <Electrolyte>
The electrolytic solution is a solution containing active material ions. An active material ion is an ion that functions as an active material. Active material ions are typically metal ions whose valences change due to oxidation-reduction. Active material ions are, for example, ions of elements selected from the group consisting of manganese, vanadium, iron, chromium, titanium, and zinc.
　正極電解液及び負極電解液の少なくとも一方の電解液は、以下の特性を有する。（１）充電時又は放電時のＳＯＣの範囲によっては副反応が生じ、副反応物が生成される。（２）副反応物を可逆反応により再溶解させることが可能である。 At least one of the positive electrode electrolyte and the negative electrode electrolyte has the following characteristics. (1) Depending on the SOC range during charging or discharging, a side reaction occurs and a side reaction product is produced. (2) It is possible to redissolve the side reactants by a reversible reaction.
　上記特性を有する電解液は、副反応が生じても、ＳＯＣの制御によって副反応物を再溶解することで、元の状態に回復させることが可能である。副反応により生成される副反応物は、例えば、活物質イオンの析出物である。 Even if a side reaction occurs, the electrolytic solution with the above characteristics can be restored to its original state by redissolving the side reaction by controlling the SOC. A side reaction product produced by a side reaction is, for example, a deposit of active material ions.
　電解液は、例えば、マンガンイオンを含有する電解液である。正極電解液がマンガンイオンを含有する電解液である場合、マンガンイオンが充電時に高ＳＯＣ領域で電解液中にマンガン酸化物として析出し得る。マンガン酸化物は、後述する電解液の回復作業によってマンガンイオンに分解され、電解液中に再溶解し得る。正極電解液がマンガンイオンを含有する電解液である場合、負極電解液は、例えばチタンイオンを含有する電解液である。 The electrolytic solution is, for example, an electrolytic solution containing manganese ions. When the positive electrode electrolyte contains manganese ions, the manganese ions may precipitate as manganese oxide in the electrolyte in the high SOC region during charging. Manganese oxide can be decomposed into manganese ions and redissolved in the electrolytic solution by the recovery operation of the electrolytic solution, which will be described later. When the positive electrode electrolyte is an electrolyte containing manganese ions, the negative electrode electrolyte is an electrolyte containing titanium ions, for example.
　〈電力変換装置〉
　電力変換装置８は、電池セル１０の充電及び放電を制御する。電池セル１０は電力変換装置８を介して充電及び放電を行う。複数のバンク２が設けられている場合、各バンク２の電池セル１０の充電及び放電は、各バンク２の電力変換装置８によって、独立して制御される。電力変換装置８は、例えば交流／直流変換装置が利用できる。 <Power converter>
The power conversion device 8 controls charging and discharging of the battery cells 10 . The battery cells 10 are charged and discharged via the power conversion device 8 . When a plurality of banks 2 are provided, the charging and discharging of the battery cells 10 of each bank 2 are independently controlled by the power conversion device 8 of each bank 2 . For example, an AC/DC converter can be used as the power conversion device 8 .
　〔制御器〕
　制御器９は、バンク２のＳＯＣを制御する。バンク２のＳＯＣとは、バンク２における電池セル１０内の電解液のＳＯＣのことである。複数のバンク２が設けられている場合、制御器９は、各バンク２の電力変換装置８を制御して、各バンク２のＳＯＣを制御する。制御器９は、電池セル１０がメインＳＯＣの利用範囲を拡大した範囲で充電又は放電を行うように電力変換装置８を制御する基本制御器９０を備える。基本制御器９０は、ＲＦ電池システム１の通常運転時に動作する。通常運転時は、電源８１０や負荷８２０につながる電力系統に対して充電又は放電を行う。 [Controller]
Controller 9 controls the SOC of bank 2 . The SOC of bank 2 is the SOC of the electrolyte in the battery cell 10 in bank 2 . When multiple banks 2 are provided, the controller 9 controls the power conversion device 8 of each bank 2 to control the SOC of each bank 2 . The controller 9 includes a basic controller 90 that controls the power conversion device 8 so that the battery cells 10 are charged or discharged within the expanded range of the main SOC. The basic controller 90 operates during normal operation of the RF battery system 1 . During normal operation, the power system connected to the power supply 810 and the load 820 is charged or discharged.
　制御器９は、電池セル１０のＳＯＣが特定状態で１０秒以上保持されるように電力変換装置８を制御する第一制御器９１を備える。第一制御器９１は、バンク２の電解液の回復作業時に動作する。バンク２の電解液の回復作業とは、バンク２における電池セル１０内で生成した副反応物を再溶解することである。副反応物は、ＲＦ電池システム１の通常運転時に電池セル１０内で生成される。副反応物は、電池セル１０内の構成部材、例えば電極に付着する。バンク２の電解液の回復作業では、主に電池セル１０内の電極に付着した副反応物を再溶解する。バンク２の電解液の回復作業時は、当該バンク２を構成する電池セル１０は電力系統に対して充電及び放電は行わない。 The controller 9 includes a first controller 91 that controls the power converter 8 so that the SOC of the battery cell 10 is held in a specific state for 10 seconds or longer. The first controller 91 operates during recovery work of the electrolyte in the bank 2 . The work of recovering the electrolyte in bank 2 is to re-dissolve the side reaction products generated in the battery cells 10 in bank 2 . Side reactants are produced within the battery cells 10 during normal operation of the RF battery system 1 . The side reactants adhere to constituent members within the battery cell 10, such as electrodes. In the operation of recovering the electrolyte in the bank 2, mainly the by-reactants adhering to the electrodes in the battery cells 10 are redissolved. During the restoration work of the electrolyte in the bank 2, the battery cells 10 forming the bank 2 do not charge or discharge the electric power system.
　制御器９は、バンク２の電力変換装置８に指令を出す。複数のバンク２が設けられている場合、制御器９は、各バンク２の電力変換装置８に指令を出す。バンク２の電力変換装置８は、制御器９からの指令に基づいて、電池セル１０の充電及び放電を制御する。制御器９は、電力系統に対して充電又は放電を行う場合は、基本制御器９０により、電池セル１０がメインＳＯＣの利用範囲を拡大した範囲のＳＯＣで充電又は放電を行うように電力変換装置８に指令を出す。制御器９は、電力系統に対して充電及び放電を行わず、バンク２の電解液の回復作業を行う場合は、第一制御器９１により、電池セル１０のＳＯＣが特定状態で１０秒以上保持されるように電力変換装置８に指令を出す。 The controller 9 issues a command to the power conversion device 8 of bank 2. When a plurality of banks 2 are provided, the controller 9 issues commands to the power converters 8 of each bank 2 . The power conversion device 8 of bank 2 controls charging and discharging of the battery cells 10 based on commands from the controller 9 . When the power system is charged or discharged, the controller 9 causes the basic controller 90 to control the power conversion device so that the battery cells 10 are charged or discharged at an SOC within an expanded range of the main SOC. Command 8. When the controller 9 does not charge or discharge the electric power system and restores the electrolyte in the bank 2, the first controller 91 keeps the SOC of the battery cell 10 in a specific state for 10 seconds or more. A command is issued to the power conversion device 8 so that the
　制御器９には、例えばコンピュータを利用できる。コンピュータは、プロセッサ、メモリ、タイマ等を備える。メモリには、プロセッサに実行させるための制御プログラム、及び各種データが格納されている。プロセッサは、メモリに格納された制御プログラムを読み出して実行する。プログラムは、制御器９による処理に関する命令群を含む。 A computer, for example, can be used as the controller 9. A computer includes a processor, memory, timers, and the like. The memory stores a control program to be executed by the processor and various data. The processor reads and executes the control program stored in the memory. The program contains instructions for processing by controller 9 .
　＜電池セルのＳＯＣ＞
　電池セル１０のＳＯＣは、ＲＦ電池システム１の通常運転時と電解液の回復作業時とで異なる。ここでの電池セル１０のＳＯＣは、電池セル１０に供給される電解液の入口側のＳＯＣと、電池セル１０から排出される電解液の出口側のＳＯＣとの平均値である。電池セル１０に供給される電解液の入口側のＳＯＣをαとする。電池セル１０から排出される電解液の出口側のＳＯＣをβとする。電池セル１０のＳＯＣの平均値は、（α＋β）／２で求められる値である。電池セル１０に供給される電解液の入口側のＳＯＣは、往路配管２４，２５に流れる電解液のＳＯＣである。電池セル１０から排出される電解液の出口側のＳＯＣは、復路配管２６，２７に流れる電解液のＳＯＣである。 <SOC of battery cell>
The SOC of the battery cell 10 differs during normal operation of the RF battery system 1 and during recovery work of the electrolyte. The SOC of the battery cell 10 here is the average value of the SOC on the inlet side of the electrolyte supplied to the battery cell 10 and the SOC on the outlet side of the electrolyte discharged from the battery cell 10 . Let α be the SOC on the inlet side of the electrolyte supplied to the battery cell 10 . Let β be the SOC on the outlet side of the electrolyte discharged from the battery cell 10 . The average value of the SOC of the battery cells 10 is a value obtained by (α+β)/2. The inlet-side SOC of the electrolytic solution supplied to the battery cell 10 is the SOC of the electrolytic solution flowing through the forward pipes 24 and 25 . The outlet-side SOC of the electrolyte discharged from the battery cell 10 is the SOC of the electrolyte flowing through the return pipes 26 and 27 .
　〔通常運転時〕
　ＲＦ電池システム１の通常運転時は、電池セル１０のＳＯＣは、メインＳＯＣの利用範囲を拡大した範囲内に制御されている。メインＳＯＣの利用範囲とは、副反応が生じ難く、副反応物が生成され難いＳＯＣの範囲である。副反応物が生成され難いＳＯＣの範囲は、例えば、一定のＳＯＣの範囲内で１週間充電及び放電した場合に、電解液中に含まれる活物質となる元素の合計量を１００モル％としたとき、副反応物の生成に消費された活物質の割合が１０モル％以下となる範囲である。上記ＳＯＣの範囲内で充電及び放電する期間は、２週間、更に１か月でもよい。上記副反応物の生成に消費された活物質の割合は、５モル％以下、更に１モル％以下が好ましい。例えば、活物質としてマンガンイオンを含有する正極電解液において、副反応物としてマンガン酸化物が生成される場合、マンガンが副反応物の生成に消費される。 [During normal operation]
During normal operation of the RF battery system 1, the SOC of the battery cells 10 is controlled within an expanded range of utilization of the main SOC. The main SOC utilization range is the SOC range in which side reactions are less likely to occur and side reaction products are less likely to be generated. The range of SOC in which side reaction products are less likely to be generated is, for example, the total amount of elements that become active materials contained in the electrolytic solution when charging and discharging for one week within a certain SOC range is set to 100 mol%. In this case, the ratio of the active material consumed in the production of the by-reactant is 10 mol % or less. The period of charging and discharging within the above SOC range may be two weeks, or even one month. The ratio of the active material consumed in the production of the above side reaction products is preferably 5 mol % or less, more preferably 1 mol % or less. For example, in a positive electrode electrolyte containing manganese ions as an active material, when manganese oxide is produced as a side-reactant, manganese is consumed in the production of the side-reactant.
　メインＳＯＣの利用範囲を拡大した範囲は、メインＳＯＣの利用範囲に加えて、充電及び放電によって副反応が生じ、副反応物が生成されるサブＳＯＣの範囲を含む。サブＳＯＣの範囲は、高ＳＯＣ領域及び低ＳＯＣ領域の少なくとも一方を含む。高ＳＯＣ領域は、メインＳＯＣの利用範囲の上限値よりもＳＯＣが高い領域である。低ＳＯＣ領域は、メインＳＯＣの利用範囲の下限値よりもＳＯＣが低い領域である。高ＳＯＣ領域及び低ＳＯＣ領域では、副反応物が生成され得る。複数の電池セル１０が設けられている場合、つまり複数の電池セル１０がセルスタック２００の形態で利用されている場合、電池セル１０のＳＯＣは、セルスタック２００の電解液のＳＯＣである。 The expanded range of usage of the main SOC includes, in addition to the range of usage of the main SOC, the range of sub-SOC where side reactions occur due to charging and discharging and side reactants are generated. The sub-SOC range includes at least one of the high SOC region and the low SOC region. The high SOC region is a region in which the SOC is higher than the upper limit of the main SOC utilization range. The low SOC region is a region in which the SOC is lower than the lower limit of the main SOC utilization range. Side reactants may be generated in the high SOC region and the low SOC region. When a plurality of battery cells 10 are provided, that is, when a plurality of battery cells 10 are used in the form of cell stack 200 , the SOC of battery cell 10 is the SOC of the electrolyte in cell stack 200 .
　メインＳＯＣの利用範囲は、使用する電解液によって異なる。メインＳＯＣの利用範囲は、使用する電解液を用いて予め試験により求められる。メインＳＯＣの利用範囲よりも拡大する範囲、即ち高ＳＯＣ領域及び低ＳＯＣ領域の各範囲は、適宜設定すればよい。ＳＯＣの利用範囲を拡大することにより、バンク２の電池容量が増え、エネルギー密度を高めることができる。高ＳＯＣ領域の範囲又は低ＳＯＣ領域の範囲は、例えば、メインＳＯＣの利用範囲の大きさの５％以上、更に１０％以上、特に１５％以上である。上記利用範囲の大きさとは、利用範囲の上限と下限との差である。 The usable range of the main SOC varies depending on the electrolyte used. The usable range of the main SOC is determined in advance by a test using the electrolytic solution to be used. A range that is wider than the range of utilization of the main SOC, that is, each range of the high SOC region and the low SOC region may be set as appropriate. By expanding the range of utilization of the SOC, the battery capacity of the bank 2 can be increased and the energy density can be increased. The range of the high SOC region or the range of the low SOC region is, for example, 5% or more, further 10% or more, particularly 15% or more of the size of the main SOC utilization range. The size of the utilization range is the difference between the upper limit and the lower limit of the utilization range.
　例えばマンガン－チタン系の電解液の場合、メインＳＯＣの利用範囲は２０％から８０％である。この場合、利用範囲の大きさは８０％－２０％＝６０％である。そして、高ＳＯＣ領域の範囲を利用範囲の大きさの１０％とした場合、高ＳＯＣ領域の範囲は６０％×１０％＝６％である。メインＳＯＣの利用範囲と高ＳＯＣ領域とを合わせたＳＯＣの利用範囲は２０％から８６％になる。この場合、メインＳＯＣの利用範囲よりもＳＯＣの利用範囲が１０％拡大することになるため、バンク２の電池容量は１０％増加する。低ＳＯＣ領域の範囲を利用範囲の大きさの１０％とした場合は、ＳＯＣの利用範囲は１４％から８０％になる。この場合も同じように、バンク２の電池容量は１０％増加することになる。 For example, in the case of a manganese-titanium electrolyte, the main SOC utilization range is 20% to 80%. In this case, the size of the utilization range is 80%-20%=60%. Assuming that the range of the high SOC region is 10% of the size of the available range, the range of the high SOC region is 60%×10%=6%. The SOC utilization range combining the main SOC utilization range and the high SOC region is from 20% to 86%. In this case, the SOC utilization range is expanded by 10% from the main SOC utilization range, so the battery capacity of bank 2 is increased by 10%. If the range of the low SOC region is 10% of the size of the usable range, the usable range of SOC is from 14% to 80%. In this case as well, the battery capacity of bank 2 will increase by 10%.
　電解液は、例えば、バナジウム系電解液であってもよい。バナジウム系電解液は、正極電解液及び負極電解液の両方がバナジウムイオンを含有する。正極電解液のバナジウムイオンと負極電解液のバナジウムイオンとは、価数が異なる。バナジウム系電解液の場合、メインＳＯＣの利用範囲は概ね５％から９５％である。 The electrolytic solution may be, for example, a vanadium-based electrolytic solution. In the vanadium-based electrolyte, both the positive electrode electrolyte and the negative electrode electrolyte contain vanadium ions. The vanadium ions in the positive electrode electrolyte and the vanadium ions in the negative electrode electrolyte have different valences. In the case of vanadium-based electrolytes, the main SOC utilization range is approximately 5% to 95%.
　メインＳＯＣの利用範囲にサブＳＯＣの利用範囲を加えた範囲が、通常運転時における電池セル１０のＳＯＣの範囲である。 The range obtained by adding the usage range of the sub SOC to the usage range of the main SOC is the SOC range of the battery cell 10 during normal operation.
　ＲＦ電池システム１の通常運転時は、電池セル１０内の電解液のＳＯＣは、正極タンク２２内の正極電解液のＳＯＣと実質的に同じであり、かつ負極タンク２３内の負極電解液のＳＯＣと実質的に同じである。「実質的に同じ」とは、電池セル１０内の電解液のＳＯＣと正極タンク２２内の正極電解液のＳＯＣとの差が５％未満であり、電池セル１０内の電解液のＳＯＣと負極タンク２３内の負極電解液のＳＯＣとの差が５％未満であることを言う。 During normal operation of the RF battery system 1, the SOC of the electrolyte in the battery cell 10 is substantially the same as the SOC of the cathode electrolyte in the cathode tank 22 and the SOC of the anode electrolyte in the anode tank 23. is substantially the same as “Substantially the same” means that the difference between the SOC of the electrolyte in the battery cell 10 and the SOC of the cathode electrolyte in the cathode tank 22 is less than 5%, and the SOC of the electrolyte in the battery cell 10 and the anode It means that the difference from the SOC of the negative electrode electrolyte in the tank 23 is less than 5%.
　〔電解液の回復作業時〕
　バンク２の電解液の回復作業時は、電池セル１０のＳＯＣは、第一制御器９１により特定状態に制御される。特定状態は、第一状態及び第二状態の少なくとも一方の状態である。第一状態は、電池セル１０内の電解液のＳＯＣが正極タンク２２内の正極電解液のＳＯＣと５％以上異なる状態である。第二状態は、電池セル１０内の電解液のＳＯＣが負極タンク２３内の負極電解液のＳＯＣと５％以上異なる状態である。電池セル１０のＳＯＣが特定状態であるとき、電池セル１０内で生成した副反応物を可逆反応により再溶解させることができる。 [During electrolyte recovery work]
The SOC of the battery cells 10 is controlled to a specific state by the first controller 91 during the recovery work of the electrolyte in the bank 2 . The specific state is at least one of the first state and the second state. The first state is a state in which the SOC of the electrolyte in the battery cell 10 differs from the SOC of the cathode electrolyte in the cathode tank 22 by 5% or more. The second state is a state in which the SOC of the electrolyte in the battery cell 10 differs from the SOC of the anode electrolyte in the anode tank 23 by 5% or more. When the SOC of the battery cell 10 is in a specific state, the side reaction product generated within the battery cell 10 can be redissolved by a reversible reaction.
　例えば、高ＳＯＣ領域で副反応物が生成されるのであれば、その副反応物は、メインＳＯＣの利用範囲よりも低い領域で再溶解されることがある。メインＳＯＣの利用範囲よりもＳＯＣが低い領域には、低ＳＯＣ領域、及び低ＳＯＣ領域よりも更にＳＯＣが低い領域が含まれる。低ＳＯＣ領域で副反応物が生成されるのであれば、その副反応物は、メインＳＯＣの利用範囲よりもＳＯＣが高い領域で再溶解されることがある。メインＳＯＣの利用範囲よりもＳＯＣが高い領域には、高ＳＯＣ領域、及び高ＳＯＣ領域よりも更にＳＯＣが高い領域が含まれる。 For example, if a side-reactant is generated in a high SOC region, the side-reactant may be re-dissolved in a region lower than the main SOC utilization range. The area where the SOC is lower than the main SOC utilization range includes a low SOC area and an area where the SOC is even lower than the low SOC area. If a side-reactant is produced in the low SOC region, the side-reactant may be re-dissolved in the higher SOC region than the main SOC utilization range. The area where the SOC is higher than the main SOC utilization range includes a high SOC area and an area where the SOC is higher than the high SOC area.
　特定状態における電池セル１０内の電解液のＳＯＣと、正極タンク２２内の正極電解液のＳＯＣ又は負極タンク２３内の負極電解液のＳＯＣとの差は、大きいほど副反応物を再溶解し易い。よって、上記差は、更に８％以上、１０％以上、１２％以上、１５％以上であってもよい。 The larger the difference between the SOC of the electrolyte in the battery cell 10 in the specific state and the SOC of the positive electrode electrolyte in the positive electrode tank 22 or the SOC of the negative electrode electrolyte in the negative electrode tank 23, the easier it is to re-dissolve the side reactants. . Therefore, the difference may be 8% or more, 10% or more, 12% or more, 15% or more.
　後述する実施形態１のように逆極性の電解液を循環させる形態では、上記差は、更に５０％以上、１００％以上、１５０％以上であってもよい。ＲＦ電池システム１の使用上、上記差は２００％未満、更に１８０％以下、特に１７０％以下、１６０％以下である。逆極性の電解液を循環させる形態では、上記差は、例えば、５％以上２００％未満、更に５０％以上１８０％以下、１００％以上１７０％以下、１５０％以上１６０％以下である。 In a mode in which reverse polarity electrolytes are circulated as in Embodiment 1 described later, the difference may be 50% or more, 100% or more, or 150% or more. For the use of the RF battery system 1, the above difference is less than 200%, even less than 180%, especially less than 170%, less than 160%. In the mode of circulating the reverse polarity electrolyte, the difference is, for example, 5% or more and less than 200%, 50% or more and 180% or less, 100% or more and 170% or less, or 150% or more and 160% or less.
　後述する実施形態２のように短時間放電を行う形態、又は後述する実施形態３のように短時間充電を行う形態では、ＲＦ電池システム１の使用上、上記差は５０％以下、更に４５％以下、特に４０％以下である。短時間放電又は短時間充電を行う形態では、上記差は、例えば、５％以上５０％以下、８％以上５０％以下、１０％以上５０％以下、１２％以上４５％以下、１５％以上４０％以下である。 In the form of performing short-time discharge as in Embodiment 2 described later, or in the form of performing short-time charging as in Embodiment 3 described later, the above difference is 50% or less, and further 45% due to the use of the RF battery system 1. below, especially below 40%. In the form of short-time discharge or short-time charge, the difference is, for example, 5% or more and 50% or less, 8% or more and 50% or less, 10% or more and 50% or less, 12% or more and 45% or less, 15% or more and 40%. % or less.
　電池セル１０のＳＯＣが特定状態に保持される時間は１０秒以上である。特定状態で１０秒以上保持されることで、副反応物を再溶解できる。上記時間は、長いほど副反応物を再溶解し易い。よって、上記時間は、更に３０秒以上、１分以上、２分以上、特に３分以上であってもよい。上記時間は、例えば１０分以下である。電池セル１０のＳＯＣが特定状態であれば、１０分以下という短時間であっても、電池セル１０内で生成した副反応物を再溶解することができる。上記時間は、例えば、１０秒以上１０分以下、更に３０秒以上１０分以下、１分以上１０分以下、２分以上１０分以下、特に３分以上１０分以下である。 The time for which the SOC of the battery cell 10 is held in the specific state is 10 seconds or longer. By maintaining the specific state for 10 seconds or longer, the side reaction product can be redissolved. The longer the time, the easier it is to re-dissolve the side reaction product. Thus, the time may also be 30 seconds or more, 1 minute or more, 2 minutes or more, especially 3 minutes or more. The above time is, for example, 10 minutes or less. If the SOC of the battery cell 10 is in the specific state, the by-reactant generated in the battery cell 10 can be redissolved even in a short time of 10 minutes or less. The time is, for example, 10 seconds or more and 10 minutes or less, further 30 seconds or more and 10 minutes or less, 1 minute or more and 10 minutes or less, 2 minutes or more and 10 minutes or less, particularly 3 minutes or more and 10 minutes or less.
　電池セル１０内の電解液のＳＯＣ、即ち電池セル１０のＳＯＣは、上述したように、電池セル１０に供給される電解液の入口側のＳＯＣと、電池セル１０から排出される電解液の出口側のＳＯＣとの平均値である。上記入口側のＳＯＣは、例えば、電池セル１０に供給される電解液と同じ電解液が供給されるモニタセルを用いて測定することができる。電池セル１０に供給される電解液とモニタセルに供給される電解液とは、同じタンクから供給される。後述する実施形態１では、図２から図５に示すように、セルスタック２００の一部のセルで構成されたモニタセル６０を用いて上記入口側のＳＯＣを測定している。モニタセル６０は充電及び放電を行わない。 The SOC of the electrolyte in the battery cell 10, that is, the SOC of the battery cell 10, is the SOC at the inlet side of the electrolyte supplied to the battery cell 10 and the SOC at the outlet of the electrolyte discharged from the battery cell 10, as described above. It is the average value with the SOC on the side. The inlet-side SOC can be measured, for example, by using a monitor cell to which the same electrolytic solution as that supplied to the battery cell 10 is supplied. The electrolyte supplied to the battery cells 10 and the electrolyte supplied to the monitor cells are supplied from the same tank. In Embodiment 1, which will be described later, as shown in FIGS. 2 to 5, the SOC on the inlet side is measured using a monitor cell 60 configured by a part of the cells of the cell stack 200. FIG. The monitor cell 60 does not charge or discharge.
　後述する実施形態２及び実施形態３では、図６及び図７に示すように、セルスタック２００とは別のモニタセル６１を用いて上記入口側のＳＯＣを測定している。モニタセル６１は、電池セル１０の上流側に設けられている。モニタセル６１は、正極電解液が流れる往路配管２４及び負極電解液が流れる往路配管２５の各々に設けられた分岐配管に接続されている。モニタセル６１は充電及び放電を行わない。 In Embodiments 2 and 3 to be described later, as shown in FIGS. 6 and 7, a monitor cell 61 different from the cell stack 200 is used to measure the SOC on the inlet side. The monitor cell 61 is provided upstream of the battery cell 10 . The monitor cell 61 is connected to branch pipes provided in each of the forward pipe 24 through which the positive electrode electrolyte flows and the forward pipe 25 through which the negative electrode electrolyte is flowed. The monitor cell 61 does not charge or discharge.
　モニタセル６０、６１は、電圧計を用いて、その開放電圧（ＯＣＶ：Ｏｐｅｎ　Ｃｉｒｃｕｉｔ　Ｖｏｌｔａｇｅ）からＳＯＣを求めることができる。 The monitor cells 60 and 61 can obtain the SOC from their open circuit voltage (OCV: Open Circuit Voltage) using a voltmeter.
　実施形態１において、モニタセル６０に代えて、実施形態２及び実施形態３と同様のモニタセル６１を用いて上記入口側のＳＯＣを測定してもよい。実施形態２及び実施形態３において、モニタセル６１に代えて、実施形態１と同様のモニタセル６０を用いて上記入口側のＳＯＣを測定してもよい。 In Embodiment 1, instead of the monitor cell 60, a monitor cell 61 similar to that of Embodiments 2 and 3 may be used to measure the inlet-side SOC. In Embodiments 2 and 3, instead of the monitor cell 61, a monitor cell 60 similar to that of Embodiment 1 may be used to measure the inlet-side SOC.
　上記出口側のＳＯＣは、上記入口側のＳＯＣ、電池セル１０に流れる電解液の流量、及び電池セル１０に流れる電解液の電流密度から演算することができる。上記出口側のＳＯＣは、電池セル１０の下流側に設けたモニタセルを用いて測定することもできる。電池セル１０の下流側にモニタセルを設ける場合、このモニタセルは、正極電解液が流れる復路配管２６及び負極電解液が流れる復路配管２７の各々に設けられた分岐配管に接続される。電池セル１０の下流側に設けたモニタセルを用いて出口側のＳＯＣを測定する場合、この測定結果、電池セル１０に流れる電解液の流量、及び電池セル１０に流れる電解液の電流密度から入口側のＳＯＣを演算することもできる。 The SOC on the outlet side can be calculated from the SOC on the inlet side, the flow rate of the electrolyte flowing through the battery cell 10, and the current density of the electrolyte flowing through the battery cell 10. The outlet-side SOC can also be measured using a monitor cell provided downstream of the battery cell 10 . When a monitor cell is provided downstream of the battery cell 10, this monitor cell is connected to branch pipes provided in each of the return pipe 26 through which the positive electrode electrolyte flows and the return pipe 27 through which the negative electrode electrolyte flows. When measuring the SOC on the outlet side using a monitor cell provided downstream of the battery cell 10, the measurement result, the flow rate of the electrolyte flowing through the battery cell 10, and the current density of the electrolyte flowing through the battery cell 10, the inlet side can also be calculated.
　正極タンク２２内の正極電解液のＳＯＣ又は負極タンク２３内の負極電解液のＳＯＣは、上記入口側のＳＯＣを測定するモニタセルを用いて演算することができる。本例では、モニタセル６０を用いて演算している。 The SOC of the positive electrode electrolyte in the positive electrode tank 22 or the SOC of the negative electrode electrolyte in the negative electrode tank 23 can be calculated using the monitor cell that measures the SOC on the inlet side. In this example, the monitor cell 60 is used for calculation.
　＜電池セルのＳＯＣを特定状態とする手段＞
　電池セル１０のＳＯＣを特定状態とする手段には、例えば以下の三つの形態がある。一つ目の形態は、高ＳＯＣ領域で副反応物が生成された場合に、正極セル１２及び負極セル１３のうち副反応物が生成されたセルに、逆極性の電解液を循環させる形態である。二つ目の形態は、高ＳＯＣ領域で副反応物が生成された場合に、短時間放電を行うことで副反応物を再溶解させる形態である。三つ目の形態は、低ＳＯＣ領域で副反応物が生成された場合に、短時間充電を行うことで副反応物を再溶解させる形態である。以下、各形態を詳細に説明する。 <Means for setting the SOC of the battery cell to a specific state>
There are, for example, the following three forms of means for setting the SOC of the battery cell 10 to a specific state. In the first mode, when the side reactant is generated in the high SOC region, the reverse polarity electrolyte is circulated to the positive electrode cell 12 or the negative electrode cell 13 where the side reactant is generated. be. The second mode is a mode in which when a side reactant is generated in a high SOC region, the side reactant is redissolved by performing short-time discharge. A third mode is a mode in which, when a side reactant is generated in a low SOC region, the side reactant is redissolved by charging for a short period of time. Each form will be described in detail below.
　≪実施形態１≫
　実施形態１では、図２から図５を参照して、上述した一つ目の形態を説明する。一つ目の形態では、バンク２は、第一の正極循環路３１と、第一の負極循環路４１と、第二の正極循環路３２及び第二の負極循環路４２の少なくとも一方の循環路とを備える。また、一つ目の形態では、バンク２は、第一切替部及び第二切替部の少なくとも一方の切替部を備える。一つ目の形態では、制御器９は、第一切替部又は第二切替部の動作を制御する第二制御器９２を備える。 <<Embodiment 1>>
In Embodiment 1, the first embodiment described above will be described with reference to FIGS. 2 to 5. FIG. In the first form, the bank 2 includes a first positive electrode circuit 31, a first negative electrode circuit 41, and at least one of the second positive electrode circuit 32 and the second negative electrode circuit 42. and Moreover, in the first form, the bank 2 includes at least one of the first switching section and the second switching section. In a first form, the controller 9 comprises a second controller 92 that controls the operation of the first switching section or the second switching section.
　第一の正極循環路３１は、正極電解液を正極タンク２２から正極セル１２を介して正極タンク２２に戻す循環路である。第一の正極循環路３１は、図１に示す往路配管２４及び復路配管２６に相当する。第一の負極循環路４１は、負極電解液を負極タンク２３から負極セル１３を介して負極タンク２３に戻す循環路である。第一の負極循環路４１は、図１に示す往路配管２５及び復路配管２７に相当する。図２から図５では、図１に示すポンプ２８、２９を省略している。第二の正極循環路３２は、正極電解液を正極タンク２２から負極セル１３を介して正極タンク２２に戻す循環路である。第二の負極循環路４２は、負極電解液を負極タンク２３から正極セル１２を介して負極タンク２３に戻す循環路である。第二の正極循環路３２及び第二の負極循環路４２は、ＲＦ電池システム１の基本構成には含まれていない。よって、第二の正極循環路３２及び第二の負極循環路４２は、図１には示されていない。 The first positive electrode circulation path 31 is a circulation path that returns the positive electrode electrolyte from the positive electrode tank 22 to the positive electrode tank 22 via the positive electrode cell 12 . The first positive electrode circulation path 31 corresponds to the outward piping 24 and the return piping 26 shown in FIG. The first negative electrode circulation path 41 is a circulation path for returning the negative electrode electrolyte from the negative electrode tank 23 to the negative electrode tank 23 via the negative electrode cell 13 . The first negative electrode circulation path 41 corresponds to the outward piping 25 and the return piping 27 shown in FIG. 2 to 5, the pumps 28, 29 shown in FIG. 1 are omitted. The second positive electrode circulation path 32 is a circulation path that returns the positive electrode electrolyte from the positive electrode tank 22 to the positive electrode tank 22 via the negative electrode cell 13 . The second negative electrode circulation path 42 is a circulation path that returns the negative electrode electrolyte from the negative electrode tank 23 to the negative electrode tank 23 via the positive electrode cell 12 . The second positive electrode circuit 32 and the second negative electrode circuit 42 are not included in the basic configuration of the RF battery system 1 . Therefore, the second positive circuit 32 and the second negative circuit 42 are not shown in FIG.
　第一切替部は、第一の正極循環路３１と第二の負極循環路４２とを切り替える切替部である。第一切替部はバルブである。第二切替部は、第一の負極循環路４１と第二の正極循環路３２とを切り替える切替部である。第二切替部はバルブである。バルブの具体的な配置や数は後述する。 The first switching section is a switching section that switches between the first positive electrode circulation path 31 and the second negative electrode circulation path 42 . The first switching part is a valve. The second switching section is a switching section that switches between the first negative electrode circulation path 41 and the second positive electrode circulation path 32 . A second switching unit is a valve. The specific arrangement and number of valves will be described later.
　第二制御器９２は、各バルブを切り替えるように制御する。制御器９は、電源８１０や負荷８２０といった電力系統に対して充電及び放電を行わず、バンク２の電解液の回復作業を行う場合は、第二制御器９２により、各バルブを切り替えるように指令を出す。各バルブを切り替えたら、制御器９は、第一制御器９１により、電池セル１０のＳＯＣが特定状態で１０秒以上保持されるように電力変換装置８に指令を出す。具体的には、各バルブを切り替えて、正極セル１２及び負極セル１３のうち副反応物が生成されたセルに、逆極性の電解液を１０秒以上循環させる。 The second controller 92 controls each valve to switch. The controller 9 does not charge or discharge the electric power system such as the power supply 810 and the load 820, and when the recovery work of the electrolyte in the bank 2 is performed, the second controller 92 instructs to switch each valve. out. After switching each valve, the first controller 91 of the controller 9 issues a command to the power conversion device 8 so that the SOC of the battery cell 10 is held in a specific state for 10 seconds or longer. Specifically, each valve is switched to circulate the electrolyte solution of the opposite polarity for 10 seconds or more to the cell in which the side reaction product is generated among the positive electrode cell 12 and the negative electrode cell 13 .
　逆極性の電解液を循環させた場合、電池セル１０内の電解液のＳＯＣと、正極タンク２２内の正極電解液のＳＯＣ又は負極タンク２３内の負極電解液のＳＯＣとの差は、正極電解液及び負極電解液の一方のＳＯＣから見た他方のＳＯＣとの差である。例えば、正極電解液及び負極電解液の各ＳＯＣが８０％であり、正極セル１２に負極電解液を循環させた場合、正極電解液のＳＯＣから見た負極電解液のＳＯＣは－８０％であり、上記差は１６０％となる。 When the reverse polarity electrolyte solution is circulated, the difference between the SOC of the electrolyte solution in the battery cell 10 and the SOC of the cathode electrolyte solution in the cathode tank 22 or the SOC of the anode electrolyte solution in the anode tank 23 is It is the difference between the SOC of one of the liquid and the negative electrode electrolyte and the SOC of the other. For example, when each SOC of the positive electrode electrolyte and the negative electrode electrolyte is 80%, and the negative electrode electrolyte is circulated in the positive electrode cell 12, the SOC of the negative electrode electrolyte viewed from the SOC of the positive electrode electrolyte is −80%. , the difference is 160%.
　第一の正極循環路３１、第一の負極循環路４１、第二の正極循環路３２、第二の負極循環路４２、第一切替部、第二切替部の配置形態によって、配管やバルブの個数、位置等が変わる。以下では、二つの配置形態を説明する。 Depending on the layout of the first positive electrode circuit 31, the first negative electrode circuit 41, the second positive electrode circuit 32, the second negative electrode circuit 42, the first switching unit, and the second switching unit, piping and valves The number, position, etc. are changed. Two arrangements are described below.
　≪実施形態１－１≫
　実施形態１－１では、図２及び図３を参照して、一つ目の配置形態を説明する。本例では、第二の正極循環路３２及び第二の負極循環路４２の双方を備える。 <<Embodiment 1-1>>
In Embodiment 1-1, the first arrangement mode will be described with reference to FIGS. 2 and 3. FIG. In this example, both the second positive electrode circuit 32 and the second negative electrode circuit 42 are provided.
　正極タンク２２から電池セル１０に正極電解液を供給する配管として、主往路配管３３と分岐往路配管３４ａ、３４ｂとを備える。主往路配管３３は、正極タンク２２につながっている。主往路配管３３には、図示しないポンプが設けられている。分岐往路配管３４ａは、主往路配管３３と正極セル１２とにつながっている。分岐往路配管３４ａには、バルブ３７ａが設けられている。分岐往路配管３４ｂは、主往路配管３３と負極セル１３とにつながっている。分岐往路配管３４ｂには、バルブ３７ｂが設けられている。 A main outbound pipe 33 and branch outbound pipes 34 a and 34 b are provided as pipes for supplying the positive electrode electrolyte from the positive electrode tank 22 to the battery cells 10 . The main outbound pipe 33 is connected to the positive electrode tank 22 . A pump (not shown) is provided in the main outbound pipe 33 . The branch outbound pipe 34 a is connected to the main outbound pipe 33 and the positive electrode cell 12 . A valve 37a is provided on the forward branch pipe 34a. The outbound branch pipe 34 b is connected to the main outbound pipe 33 and the negative electrode cell 13 . A valve 37b is provided on the forward branch pipe 34b.
　電池セル１０から正極タンク２２に正極電解液を戻す配管として、主復路配管３５と分岐復路配管３６ａ、３６ｂとを備える。主復路配管３５は、正極タンク２２につながっている。分岐復路配管３６ａは、主復路配管３５と正極セル１２とにつながっている。分岐復路配管３６ａには、バルブ３８ａが設けられている。分岐復路配管３６ｂは、主復路配管３５と負極セル１３とにつながっている。分岐復路配管３６ｂには、バルブ３８ｂが設けられている。 A main return pipe 35 and branch return pipes 36 a and 36 b are provided as pipes for returning the positive electrode electrolyte from the battery cell 10 to the positive electrode tank 22 . The main return pipe 35 is connected to the positive electrode tank 22 . The branch return pipe 36 a is connected to the main return pipe 35 and the positive electrode cell 12 . A valve 38a is provided in the branch return pipe 36a. The branch return pipe 36 b is connected to the main return pipe 35 and the negative electrode cell 13 . A valve 38b is provided in the branch return pipe 36b.
　第一の正極循環路３１では、第一の正極循環路３１に正極電解液を流通させるために、バルブ３７ａ及びバルブ３８ａが開放されている。バルブ３７ｂ及びバルブ３８ｂは閉鎖されている。第一の正極循環路３１では、正極電解液は、正極タンク２２から主往路配管３３及び分岐往路配管３４ａを通って正極セル１２に供給され、正極セル１２から分岐復路配管３６ａ及び主復路配管３５を通って正極タンク２２に戻される。 In the first positive electrode circulation path 31, the valves 37a and 38a are opened in order to allow the positive electrode electrolyte to flow through the first positive electrode circulation path 31. Valves 37b and 38b are closed. In the first positive electrode circuit 31, the positive electrode electrolyte is supplied from the positive electrode tank 22 to the positive electrode cell 12 through the main outbound pipe 33 and the branched outbound pipe 34a, and from the positive electrode cell 12 to the branched return pipe 36a and the main return pipe 35. is returned to the positive electrode tank 22 through .
　第二の正極循環路３２では、第二の正極循環路３２に正極電解液を流通させるために、バルブ３７ｂ及びバルブ３８ｂが開放されている。バルブ３７ａ及びバルブ３８ａは閉鎖されている。第二の正極循環路３２では、正極電解液は、正極タンク２２から主往路配管３３及び分岐往路配管３４ｂを通って負極セル１３に供給され、負極セル１３から分岐復路配管３６ｂ及び主復路配管３５を通って正極タンク２２に戻される。 In the second positive electrode circulation path 32, the valves 37b and 38b are opened in order to allow the positive electrode electrolyte to flow through the second positive electrode circulation path 32. Valves 37a and 38a are closed. In the second positive electrode circuit 32, the positive electrode electrolyte is supplied from the positive electrode tank 22 to the negative electrode cell 13 through the main outbound pipe 33 and the branched outbound pipe 34b. is returned to the positive electrode tank 22 through .
　負極タンク２３から電池セル１０に負極電解液を供給する配管として、主往路配管４３と分岐往路配管４４ａ、４４ｂとを備える。主往路配管４３は、負極タンク２３につながっている。主往路配管４３には、図示しないポンプが設けられている。分岐往路配管４４ａは、主往路配管４３と負極セル１３とにつながっている。分岐往路配管４４ａには、バルブ４７ａが設けられている。分岐往路配管４４ｂは、主往路配管４３と正極セル１２とにつながっている。分岐往路配管４４ｂには、バルブ４７ｂが設けられている。 A main outbound pipe 43 and branch outbound pipes 44 a and 44 b are provided as pipes for supplying the negative electrode electrolyte from the negative electrode tank 23 to the battery cells 10 . The main outbound pipe 43 is connected to the negative electrode tank 23 . A pump (not shown) is provided in the main outbound pipe 43 . The branch outbound pipe 44 a is connected to the main outbound pipe 43 and the negative electrode cell 13 . A valve 47a is provided on the forward branch pipe 44a. The branch outbound pipe 44 b is connected to the main outbound pipe 43 and the positive electrode cell 12 . A valve 47b is provided on the forward branch pipe 44b.
　電池セル１０から負極タンク２３に負極電解液を戻す配管として、主復路配管４５と分岐復路配管４６ａ、４６ｂとを備える。主復路配管４５は、負極タンク２３につながっている。分岐復路配管４６ａは、主復路配管４５と負極セル１３とにつながっている。分岐復路配管４６ａには、バルブ４８ａが設けられている。分岐復路配管４６ｂは、主復路配管４５と正極セル１２とにつながっている。分岐復路配管４６ｂには、バルブ４８ｂが設けられている。 A main return pipe 45 and branch return pipes 46 a and 46 b are provided as pipes for returning the negative electrode electrolyte from the battery cell 10 to the negative electrode tank 23 . The main return pipe 45 is connected to the negative electrode tank 23 . The branch return pipe 46 a is connected to the main return pipe 45 and the negative electrode cell 13 . A valve 48a is provided in the branch return pipe 46a. The branch return pipe 46 b is connected to the main return pipe 45 and the positive electrode cell 12 . A valve 48b is provided in the branch return pipe 46b.
　第一の負極循環路４１では、第一の負極循環路４１に負極電解液を流通させるために、バルブ４７ａ及びバルブ４８ａが開放されている。バルブ４７ｂ及びバルブ４８ｂは閉鎖されている。第一の負極循環路４１では、負極電解液は、負極タンク２３から主往路配管４３及び分岐往路配管４４ａを通って負極セル１３に供給され、負極セル１３から分岐復路配管４６ａ及び主復路配管４５を通って負極タンク２３に戻される。 In the first negative electrode circulation path 41, the valves 47a and 48a are opened in order to allow the negative electrode electrolyte to flow through the first negative electrode circulation path 41. Valve 47b and valve 48b are closed. In the first negative electrode circuit 41, the negative electrode electrolyte is supplied from the negative electrode tank 23 to the negative electrode cell 13 through the main outbound pipe 43 and the branched outbound pipe 44a. is returned to the negative electrode tank 23 through .
　第二の負極循環路４２では、第二の負極循環路４２に負極電解液を流通させるために、バルブ４７ｂ及びバルブ４８ｂが開放されている。バルブ４７ａ及びバルブ４８ａは閉鎖されている。第二の負極循環路４２では、負極電解液は、負極タンク２３から主往路配管４３及び分岐往路配管４４ｂを通って正極セル１２に供給され、正極セル１２から分岐復路配管４６ｂ及び主復路配管４５を通って負極タンク２３に戻される。 In the second negative electrode circuit 42, the valves 47b and 48b are opened in order to allow the negative electrode electrolyte to flow through the second negative electrode circuit 42. Valve 47a and valve 48a are closed. In the second negative electrode circuit 42, the negative electrode electrolyte is supplied from the negative electrode tank 23 to the positive electrode cell 12 through the main outbound pipe 43 and the branched outbound pipe 44b. is returned to the negative electrode tank 23 through .
　バルブ３７ａ、４７ｂ、３８ａ、４８ｂが第一切替部である。バルブ３７ｂ、４７ａ、３８ｂ、４８ａが第二切替部である。 The valves 37a, 47b, 38a, and 48b are the first switching parts. Valves 37b, 47a, 38b, and 48a are second switching units.
　〔通常運転時〕
　ＲＦ電池システム１の通常運転時は、第二制御器９２は、正極セル１２に正極電解液を循環させ、かつ負極セル１３に負極電解液を循環させるように、第一切替部又は第二切替部の動作を制御する。ＲＦ電池システム１の通常運転時は、第二制御器９２により、バルブ３７ａ、３８ａ、４７ａ、４８ａが開放され、バルブ３７ｂ、３８ｂ、４７ｂ、４８ｂが閉じられた状態となる。ＲＦ電池システム１の通常運転時は、図２に示すように、第一の正極循環路３１にて正極セル１２に正極電解液が循環され、第一の負極循環路４１にて負極セル１３に負極電解液が循環されている。図２に示す白抜き矢印が電解液の流れである。図２に示す太線の配管３３、３４ａ、３６ａ、３５は、正極電解液が流通される配管である。図２に示す太線の配管４３、４４ａ、４６ａ、４５は、負極電解液が流通される配管である。 [During normal operation]
During normal operation of the RF battery system 1, the second controller 92 circulates the positive electrode electrolyte in the positive electrode cell 12 and circulates the negative electrode electrolyte in the negative electrode cell 13. control the operation of the During normal operation of the RF battery system 1, the second controller 92 opens the valves 37a, 38a, 47a, 48a and closes the valves 37b, 38b, 47b, 48b. During normal operation of the RF battery system 1, as shown in FIG. A negative electrode electrolyte is circulated. The white arrows shown in FIG. 2 indicate the flow of the electrolytic solution. Thick- line pipes 33, 34a, 36a, and 35 shown in FIG. 2 are pipes through which the positive electrode electrolyte is distributed. Thick- line pipes 43, 44a, 46a, and 45 shown in FIG. 2 are pipes through which the negative electrode electrolyte is distributed.
　〔電解液の回復作業時〕
　バンク２の電解液の回復作業時は、第二制御器９２は、正極セル１２及び負極セル１３のうち副反応物が生成されたセルに、逆極性の電解液を循環させるように、第一切替部又は第二切替部の動作を制御する。例えば、正極セル１２に副反応物が生成された場合、第二制御器９２は、正極セル１２に負極電解液を循環させるように、第一切替部の動作を制御する。第二制御器９２は、第一の正極循環路３１と第二の負極循環路４２とを切り替える第一切替部として、バルブ３７ａとバルブ４７ｂとを切り替え、バルブ３８ａとバルブ４８ｂとを切り替える。第二制御器９２により、バルブ４７ａ、４８ａ、４７ｂ、４８ｂが開放され、バルブ３７ａ、３８ａ、３７ｂ、３８ｂが閉じられた状態となる。本例では、バンク２の電解液の回復作業時は、図３に示すように、第二の負極循環路４２にて正極セル１２に負極電解液が循環され、第一の負極循環路４１にて負極セル１３に負極電解液が循環されている。図３に示す白抜き矢印が電解液の流れである。図３に示す太線の配管４３、４４ａ、４４ｂ、４６ａ、４６ｂ、４５は、負極電解液が流通される配管である。 [During electrolyte recovery work]
During the recovery work of the electrolyte in the bank 2, the second controller 92 circulates the electrolyte of opposite polarity to the positive electrode cell 12 and the negative electrode cell 13 in which the side reaction product is generated. It controls the operation of the switching unit or the second switching unit. For example, when a by-reactant is generated in the positive electrode cell 12 , the second controller 92 controls the operation of the first switching section so that the negative electrode electrolyte is circulated through the positive electrode cell 12 . The second controller 92 switches between the valves 37a and 47b and switches between the valves 38a and 48b as a first switching unit that switches between the first positive electrode circulation path 31 and the second negative electrode circulation path 42 . The second controller 92 opens the valves 47a, 48a, 47b, 48b and closes the valves 37a, 38a, 37b, 38b. In this example, during recovery work of the electrolyte in the bank 2, as shown in FIG. The negative electrode electrolyte is circulated to the negative electrode cell 13 by The white arrows shown in FIG. 3 indicate the flow of the electrolytic solution. Thick- line pipes 43, 44a, 44b, 46a, 46b, and 45 shown in FIG. 3 are pipes through which the negative electrode electrolyte flows.
　正極セル１２にのみ副反応物が生成される場合、バンク２の電解液の回復作業では、正極セル１２に負極電解液を循環させるが、負極セル１３に正極電解液を循環させなくてもよい。この場合、図２及び図３に示す第二の正極循環路３２は省略できる。 When a side reaction product is generated only in the positive electrode cell 12, the negative electrode electrolyte is circulated in the positive electrode cell 12 in the recovery operation of the electrolyte in the bank 2, but the positive electrode electrolyte does not have to be circulated in the negative electrode cell 13. . In this case, the second positive electrode circuit 32 shown in FIGS. 2 and 3 can be omitted.
　負極セル１３に副反応物が生成された場合は、第二制御器９２は、負極セル１３に正極電解液を循環させるように、第二切替部の動作を制御する。この場合、第二制御器９２は、第一の負極循環路４１と第二の正極循環路３２とを切り替える第二切替部として、バルブ３７ｂとバルブ４７ａとを切り替え、バルブ３８ｂとバルブ４８ａとを切り替える。 When a by-reactant is generated in the negative electrode cell 13, the second controller 92 controls the operation of the second switching unit so that the positive electrode electrolyte is circulated through the negative electrode cell 13. In this case, the second controller 92 switches between the valves 37b and 47a as a second switching unit for switching between the first negative electrode circuit 41 and the second positive electrode circuit 32, and switches between the valves 38b and 48a. switch.
　負極セル１３にのみ副反応物が生成される場合、バンク２の電解液の回復作業では、負極セル１３に正極電解液を循環させるが、正極セル１２に負極電解液を循環させなくてもよい。この場合、図２及び図３に示す第二の負極循環路４２は省略できる。 When a side reaction product is generated only in the negative electrode cell 13, the positive electrode electrolyte is circulated in the negative electrode cell 13 in the recovery operation of the electrolyte in the bank 2, but the negative electrode electrolyte does not have to be circulated in the positive electrode cell 12. . In this case, the second negative electrode circuit 42 shown in FIGS. 2 and 3 can be omitted.
　実施形態１－１のＲＦ電池システム１によれば、第二制御器９２によって第一切替部又は第二切替部の動作を制御することで、正極セル１２又は負極セル１３に逆極性の電解液を循環させることができる。例えば、正極セル１２に副反応物が生成された場合、正極セル１２に負極電解液を循環させることができる。正極セル１２に負極電解液を循環させることで、電池セル１０内の電解液のＳＯＣを特定状態とでき、正極セル１２内に生成された副反応物を再溶解することができる。 According to the RF battery system 1 of Embodiment 1-1, by controlling the operation of the first switching unit or the second switching unit by the second controller 92, the positive electrode cell 12 or the negative electrode cell 13 electrolyte solution of opposite polarity can be circulated. For example, when a side reaction product is generated in the positive electrode cell 12 , the negative electrode electrolyte can be circulated through the positive electrode cell 12 . By circulating the negative electrode electrolyte in the positive electrode cell 12, the SOC of the electrolyte in the battery cell 10 can be brought to a specific state, and the side reaction product generated in the positive electrode cell 12 can be redissolved.
　≪実施形態１－２≫
　実施形態１－２では、図４及び図５を参照して、二つ目の配置形態を説明する。本例では、第二の正極循環路３２及び第二の負極循環路４２の双方を備える。 <<Embodiment 1-2>>
In Embodiment 1-2, a second arrangement mode will be described with reference to FIGS. 4 and 5. FIG. In this example, both the second positive electrode circuit 32 and the second negative electrode circuit 42 are provided.
　正極タンク２２から正極セル１２に正極電解液を供給する配管として、主往路配管３３ａと共通往路配管３９ａとを備える。主往路配管３３ａは、正極タンク２２につながっている。主往路配管３３ａには、図示しないポンプが設けられている。共通往路配管３９ａは、主往路配管３３ａと正極セル１２とにつながっている。共通往路配管３９ａには、通常運転時は正極電解液が流れ、後述する三方バルブ３９０ａの切り替えによって負極電解液が流れることもある。 A main outbound pipe 33 a and a common outbound pipe 39 a are provided as pipes for supplying the positive electrode electrolyte from the positive electrode tank 22 to the positive electrode cell 12 . The main outbound pipe 33 a is connected to the positive electrode tank 22 . A pump (not shown) is provided in the main outbound pipe 33a. Common outbound pipe 39 a is connected to main outbound pipe 33 a and positive electrode cell 12 . During normal operation, the positive electrode electrolyte flows through the common outward pipe 39a, and the negative electrode electrolyte may flow through the switching of the three-way valve 390a, which will be described later.
　正極セル１２から正極タンク２２に正極電解液を戻す配管として、主復路配管３５ａと共通復路配管３９ｃとを備える。主復路配管３５ａは、正極タンク２２につながっている。共通復路配管３９ｃは、主復路配管３５ａと正極セル１２とにつながっている。共通復路配管３９ｃには、通常運転時は正極電解液が流れ、後述する三方バルブ３９０ｃの切り替えによって負極電解液が流れることもある。 A main return pipe 35 a and a common return pipe 39 c are provided as pipes for returning the positive electrode electrolyte from the positive electrode cell 12 to the positive electrode tank 22 . The main return pipe 35 a is connected to the positive electrode tank 22 . The common return pipe 39 c is connected to the main return pipe 35 a and the positive electrode cell 12 . The positive electrode electrolyte flows through the common return pipe 39c during normal operation, and the negative electrode electrolyte may flow through the switching of the three-way valve 390c, which will be described later.
　正極タンク２２から負極セル１３に正極電解液を供給する配管として、主往路配管３３ｂと共通往路配管３９ｂとを備える。主往路配管３３ｂは、正極タンク２２につながっている。主往路配管３３ｂには、図示しないポンプが設けられている。共通往路配管３９ｂは、主往路配管３３ｂと負極セル１３とにつながっている。共通往路配管３９ｂには、通常運転時は負極電解液が流れ、後述する三方バルブ３９０ｂの切り替えによって正極電解液が流れることもある。 A main outbound pipe 33 b and a common outbound pipe 39 b are provided as pipes for supplying the positive electrode electrolyte from the positive electrode tank 22 to the negative electrode cell 13 . The main outbound pipe 33 b is connected to the positive electrode tank 22 . A pump (not shown) is provided in the main outbound pipe 33b. The common outbound pipe 39 b is connected to the main outbound pipe 33 b and the negative electrode cell 13 . During normal operation, the negative electrode electrolyte flows through the common outward pipe 39b, and the positive electrode electrolyte may flow through the switching of the three-way valve 390b, which will be described later.
　負極セル１３から正極タンク２２に正極電解液を戻す配管として、主復路配管３５ｂと共通復路配管３９ｄとを備える。主復路配管３５ｂは、正極タンク２２につながっている。共通復路配管３９ｄは、主復路配管３５ｂと負極セル１３とにつながっている。共通復路配管３９ｄには、通常運転時は負極電解液が流れ、後述する三方バルブ３９０ｄの切り替えによって正極電解液が流れることもある。 A main return pipe 35 b and a common return pipe 39 d are provided as pipes for returning the positive electrode electrolyte from the negative electrode cell 13 to the positive electrode tank 22 . The main return pipe 35 b is connected to the positive electrode tank 22 . The common return pipe 39 d is connected to the main return pipe 35 b and the negative electrode cell 13 . A negative electrode electrolyte flows through the common return pipe 39d during normal operation, and a positive electrode electrolyte may flow through the common return pipe 39d by switching a three-way valve 390d, which will be described later.
　負極タンク２３から負極セル１３に負極電解液を供給する配管として、主往路配管４３ｂと共通往路配管３９ｂとを備える。主往路配管３３ｂは、負極タンク２３につながっている。主往路配管３３ｂには、図示しないポンプが設けられている。共通往路配管３９ｂは、主往路配管４３ｂと負極セル１３とにつながっている。 A main outbound pipe 43 b and a common outbound pipe 39 b are provided as pipes for supplying the negative electrode electrolyte from the negative electrode tank 23 to the negative electrode cell 13 . The main outbound pipe 33 b is connected to the negative electrode tank 23 . A pump (not shown) is provided in the main outbound pipe 33b. The common outbound pipe 39 b is connected to the main outbound pipe 43 b and the negative electrode cell 13 .
　負極セル１３から負極タンク２３に負極電解液を戻す配管として、主復路配管４５ｂと共通復路配管３９ｄとを備える。主復路配管４５ｂは、負極タンク２３につながっている。共通復路配管３９ｄは、主復路配管４５ｂと負極セル１３とにつながっている。 As piping for returning the negative electrode electrolyte from the negative electrode cell 13 to the negative electrode tank 23, a main return line 45b and a common return line 39d are provided. The main return pipe 45 b is connected to the negative electrode tank 23 . The common return pipe 39 d is connected to the main return pipe 45 b and the negative electrode cell 13 .
　負極タンク２３から正極セル１２に負極電解液を供給する配管として、主往路配管４３ａと共通往路配管３９ａとを備える。主往路配管４３ａは、負極タンク２３につながっている。主往路配管４３ａには、図示しないポンプが設けられている。共通往路配管３９ａは、主往路配管４３ａと正極セル１２とにつながっている。 A main outbound pipe 43 a and a common outbound pipe 39 a are provided as pipes for supplying the negative electrode electrolyte from the negative electrode tank 23 to the positive electrode cell 12 . The main outbound pipe 43 a is connected to the negative electrode tank 23 . A pump (not shown) is provided in the main outbound pipe 43a. The common outbound pipe 39 a is connected to the main outbound pipe 43 a and the positive electrode cell 12 .
　正極セル１２から負極タンク２３に負極電解液を戻す配管として、主復路配管４５ａと共通復路配管３９ｃとを備える。主復路配管４５ａは、負極タンク２３につながっている。共通復路配管３９ｃは、主復路配管４５ａと正極セル１２とにつながっている。 A main return pipe 45 a and a common return pipe 39 c are provided as pipes for returning the negative electrode electrolyte from the positive electrode cell 12 to the negative electrode tank 23 . The main return pipe 45 a is connected to the negative electrode tank 23 . The common return pipe 39 c is connected to the main return pipe 45 a and the positive electrode cell 12 .
　共通往路配管３９ａと主往路配管３３ａと主往路配管４３ａとの接続箇所には、三方バルブ３９０ａが設けられている。三方バルブ３９０ａの切り替えによって、主往路配管３３ａから共通往路配管３９ａに正極電解液が流れるか、主往路配管４３ａから共通往路配管３９ａに負極電解液が流れるかが切り替えられる。共通往路配管３９ｂと主往路配管３３ｂと主往路配管４３ｂとの接続箇所には、三方バルブ３９０ｂが設けられている。三方バルブ３９０ｂの切り替えによって、主往路配管３３ｂから共通往路配管３９ｂに正極電解液が流れるか、主往路配管４３ｂから共通往路配管３９ｂに負極電解液が流れるかが切り替えられる。共通復路配管３９ｃと主復路配管３５ａと主復路配管４５ａとの接続箇所には、三方バルブ３９０ｃが設けられている。三方バルブ３９０ｃの切り替えによって、正極セル１２から排出された電解液の極性に応じて、共通復路配管３９ｃから主復路配管３５ａに正極電解液が流れるか、共通復路配管３９ｃから主復路配管４５ａに負極電解液が流れるかが切り替えられる。共通復路配管３９ｄと主復路配管３５ｂと主復路配管４５ｂとの接続箇所には、三方バルブ３９０ｄが設けられている。三方バルブ３９０ｄの切り替えによって、負極セル１３から排出された電解液の極性に応じて、共通復路配管３９ｄから主復路配管３５ｂに正極電解液が流れるか、共通復路配管３９ｄから主復路配管４５ｂに負極電解液が流れるかが切り替えられる。 A three-way valve 390a is provided at a connection point between the common outward pipe 39a, the main outward pipe 33a, and the main outward pipe 43a. By switching the three-way valve 390a, it is possible to switch whether the positive electrode electrolyte flows from the main outward pipe 33a to the common outward pipe 39a or the negative electrode electrolyte flows from the main outward pipe 43a to the common outward pipe 39a. A three-way valve 390b is provided at a connection point between the common outward pipe 39b, the main outward pipe 33b, and the main outward pipe 43b. By switching the three-way valve 390b, it is possible to switch whether the positive electrode electrolyte flows from the main outward pipe 33b to the common outward pipe 39b or the negative electrode electrolyte flows from the main outward pipe 43b to the common outward pipe 39b. A three-way valve 390c is provided at a connection point between the common return pipe 39c, the main return pipe 35a, and the main return pipe 45a. By switching the three-way valve 390c, depending on the polarity of the electrolyte discharged from the positive electrode cell 12, the positive electrode electrolyte flows from the common return pipe 39c to the main return pipe 35a, or from the common return pipe 39c to the main return pipe 45a. It is possible to switch whether the electrolytic solution flows. A three-way valve 390d is provided at a connection point between the common return pipe 39d, the main return pipe 35b, and the main return pipe 45b. By switching the three-way valve 390d, depending on the polarity of the electrolyte discharged from the negative electrode cell 13, the positive electrode electrolyte flows from the common return pipe 39d to the main return pipe 35b, or from the common return pipe 39d to the main return pipe 45b. It is possible to switch whether the electrolytic solution flows.
　第一の正極循環路３１では、三方バルブ３９０ａは主往路配管３３ａと共通往路配管３９ａとを連通し、主往路配管４３ａと共通往路配管３９ａとを遮断している。第一の正極循環路３１では、三方バルブ３９０ｃは主復路配管３５ａと共通復路配管３９ｃとを連通し、主復路配管４５ａと共通復路配管３９ｃとを遮断している。第一の正極循環路３１では、正極電解液は、正極タンク２２から主往路配管３３ａ及び共通往路配管３９ａを通って正極セル１２に供給され、正極セル１２から共通復路配管３９ｃ及び主復路配管３５ａを通って正極タンク２２に戻される。 In the first positive electrode circulation path 31, the three-way valve 390a connects the main outward piping 33a and the common outward piping 39a, and blocks the main outward piping 43a and the common outward piping 39a. In the first positive electrode circulation path 31, the three-way valve 390c connects the main return pipe 35a and the common return pipe 39c, and blocks the main return pipe 45a and the common return pipe 39c. In the first positive electrode circulation path 31, the positive electrode electrolyte is supplied from the positive electrode tank 22 to the positive electrode cell 12 through the main outward pipe 33a and the common outward pipe 39a, and from the positive electrode cell 12, the common return pipe 39c and the main return pipe 35a. is returned to the positive electrode tank 22 through .
　第二の正極循環路３２では、三方バルブ３９０ｂは主往路配管３３ｂと共通往路配管３９ｂとを連通し、主往路配管４３ｂと共通往路配管３９ｂとを遮断している。第二の正極循環路３２では、三方バルブ３９０ｄは主復路配管３５ｂと共通復路配管３９ｄとを連通し、主復路配管４５ｂと共通復路配管３９ｄとを遮断している。第二の正極循環路３２では、正極電解液は、正極タンク２２から主往路配管３３ｂ及び共通往路配管３９ｂを通って負極セル１３に供給され、負極セル１３から共通復路配管３９ｄ及び主復路配管３５ｂを通って正極タンク２２に戻される。 In the second positive electrode circulation path 32, the three-way valve 390b communicates the main outward piping 33b and the common outward piping 39b, and blocks the main outward piping 43b and the common outward piping 39b. In the second positive electrode circuit 32, the three-way valve 390d communicates the main return pipe 35b and the common return pipe 39d, and shuts off the main return pipe 45b and the common return pipe 39d. In the second positive electrode circuit 32, the positive electrode electrolyte is supplied from the positive electrode tank 22 to the negative electrode cell 13 through the main outbound pipe 33b and the common outbound pipe 39b, and from the negative electrode cell 13 through the common return pipe 39d and the main return pipe 35b. is returned to the positive electrode tank 22 through .
　第一の負極循環路４１では、三方バルブ３９０ｂは主往路配管４３ｂと共通往路配管３９ｂとを連通し、主往路配管３３ｂと共通往路配管３９ｂとを遮断している。第一の負極循環路４１では、三方バルブ３９０ｄは主復路配管４５ｂと共通復路配管３９ｄとを連通し、主復路配管３５ｂと共通復路配管３９ｄとを遮断している。第一の負極循環路４１では、負極電解液は、負極タンク２３から主往路配管４３ｂ及び共通往路配管３９ｂを通って負極セル１３に供給され、負極セル１３から共通復路配管３９ｄ及び主復路配管４５ｂを通って負極タンク２３に戻される。 In the first negative electrode circulation path 41, the three-way valve 390b communicates the main outward piping 43b and the common outward piping 39b, and blocks the main outward piping 33b and the common outward piping 39b. In the first negative electrode circuit 41, the three-way valve 390d connects the main return pipe 45b and the common return pipe 39d, and shuts off the main return pipe 35b and the common return pipe 39d. In the first negative electrode circuit 41, the negative electrode electrolyte is supplied from the negative electrode tank 23 to the negative electrode cell 13 through the main outbound pipe 43b and the common outbound pipe 39b, and from the negative electrode cell 13, the common return pipe 39d and the main return pipe 45b. is returned to the negative electrode tank 23 through .
　第二の負極循環路４２では、三方バルブ３９０ａは主往路配管４３ａと共通往路配管３９ａとを連通し、主往路配管３３ａと共通往路配管３９ａとを遮断している。第二の負極循環路４２では、三方バルブ３９０ｃは主復路配管４５ａと共通復路配管３９ｃとを連通し、主復路配管３５ａと共通復路配管３９ｃとを遮断している。第二の負極循環路４２では、負極電解液は、負極タンク２３から主往路配管４３ａ及び共通往路配管３９ａを通って正極セル１２に供給され、正極セル１２から共通復路配管３９ｃ及び主復路配管４５ａを通って負極タンク２３に戻される。 In the second negative electrode circulation path 42, the three-way valve 390a communicates the main outward piping 43a and the common outward piping 39a, and blocks the main outward piping 33a and the common outward piping 39a. In the second negative electrode circuit 42, the three-way valve 390c connects the main return pipe 45a and the common return pipe 39c, and blocks the main return pipe 35a and the common return pipe 39c. In the second negative electrode circuit 42, the negative electrode electrolyte is supplied from the negative electrode tank 23 to the positive electrode cell 12 through the main outbound pipe 43a and the common outbound pipe 39a, and from the positive electrode cell 12, the common return pipe 39c and the main return pipe 45a. is returned to the negative electrode tank 23 through .
　三方バルブ３９０ａ、３９０ｃが第一切替部である。三方バルブ３９０ｂ、３９０ｄが第二切替部である。 The three- way valves 390a and 390c are the first switching parts. Three- way valves 390b and 390d are second switching units.
　〔通常運転時〕
　ＲＦ電池システム１の通常運転時は、第二制御器９２は、正極セル１２に正極電解液を循環させ、かつ負極セル１３に負極電解液を循環させるように、第一切替部又は第二切替部の動作を制御する。ＲＦ電池システム１の通常運転時は、第二制御器９２により、三方バルブ３９０ａにより主往路配管３３ａと共通往路配管３９ａとが連通し、三方バルブ３９０ｃにより共通復路配管３９ｃと主復路配管３５ａとが連通した状態となる。また、ＲＦ電池システム１の通常運転時は、第二制御器９２により、三方バルブ３９０ｂにより主往路配管４３ｂと共通往路配管３９ｂとが連通し、三方バルブ３９０ｄにより共通復路配管３９ｄと主復路配管４５ｂとが連通した状態となる。ＲＦ電池システム１の通常運転時は、図４に示すように、第一の正極循環路３１にて正極セル１２に正極電解液が循環され、第一の負極循環路４１にて負極セル１３に負極電解液が循環されている。図４に示す白抜き矢印が電解液の流れである。図４に示す太線の配管３３ａ、３９ａ、３９ｃ、３５ａは、正極電解液が流通される配管である。図４に示す太線の配管４３ｂ、３９ｂ、３９ｄ、４５ｂは、負極電解液が流通される配管である。 [During normal operation]
During normal operation of the RF battery system 1, the second controller 92 circulates the positive electrode electrolyte in the positive electrode cell 12 and circulates the negative electrode electrolyte in the negative electrode cell 13. control the operation of the During normal operation of the RF battery system 1, the second controller 92 causes the three-way valve 390a to connect the main outbound pipe 33a and the common outward pipe 39a, and the three-way valve 390c to connect the common return pipe 39c and the main return pipe 35a. It will be in a state of communication. Further, during normal operation of the RF battery system 1, the second controller 92 causes the three-way valve 390b to communicate the main outward pipe 43b and the common outward pipe 39b, and the three-way valve 390d to communicate the common return pipe 39d and the main return pipe 45b. are in communication with each other. During normal operation of the RF battery system 1, as shown in FIG. A negative electrode electrolyte is circulated. The white arrows shown in FIG. 4 indicate the flow of the electrolytic solution. Thick- line pipes 33a, 39a, 39c, and 35a shown in FIG. 4 are pipes through which the positive electrode electrolyte flows. Thick- line pipes 43b, 39b, 39d, and 45b shown in FIG. 4 are pipes through which the negative electrode electrolyte flows.
　〔電解液の回復作業時〕
　バンク２の電解液の回復作業時は、第二制御器９２は、正極セル１２及び負極セル１３のうち副反応物が生成されたセルに、逆極性の電解液を循環させるように、第一切替部又は第二切替部の動作を制御する。例えば、正極セル１２に副反応物が生成された場合、第二制御器９２は、正極セル１２に負極電解液を循環させるように、第一切替部の動作を制御する。第二制御器９２は、第一の正極循環路３１と第二の負極循環路４２とを切り替える第一切替部として、主往路配管４３ａと共通往路配管３９ａとが連通するように三方バルブ３９０ａを切り替えると共に、共通復路配管３９ｃと主復路配管４５ａとが連通するように三方バルブ３９０ｃを切り替える。バンク２の電解液の回復作業時は、図５に示すように、第二の負極循環路４２にて正極セル１２に負極電解液が循環され、第一の負極循環路４１にて負極セル１３に負極電解液が循環されている。図５に示す白抜き矢印が電解液の流れである。図５に示す太線の配管４３ａ、４３ｂ、３９ａ、３９ｂ、３９ｃ、３９ｄ、４５ａ、４５ｂは、負極電解液が流通される配管である。 [During electrolyte recovery work]
During the recovery work of the electrolyte in the bank 2, the second controller 92 circulates the electrolyte of opposite polarity to the positive electrode cell 12 and the negative electrode cell 13 in which the side reaction product is generated. It controls the operation of the switching unit or the second switching unit. For example, when a by-reactant is generated in the positive electrode cell 12 , the second controller 92 controls the operation of the first switching section so that the negative electrode electrolyte is circulated through the positive electrode cell 12 . The second controller 92 operates the three-way valve 390a as a first switching unit for switching between the first positive electrode circulation path 31 and the second negative electrode circulation path 42 so that the main outward piping 43a and the common outward piping 39a communicate with each other. Along with switching, the three-way valve 390c is switched so that the common return pipe 39c and the main return pipe 45a are communicated with each other. During recovery work of the electrolyte in the bank 2, as shown in FIG. The negative electrode electrolyte is circulated in the White arrows shown in FIG. 5 indicate the flow of the electrolytic solution. Thick- line pipes 43a, 43b, 39a, 39b, 39c, 39d, 45a, and 45b shown in FIG. 5 are pipes through which the negative electrode electrolyte flows.
　負極セル１３に副反応物が生成された場合は、第二制御器９２は、負極セル１３に正極電解液を循環させるように、第二切替部の動作を制御する。この場合、第二制御器９２は、第一の負極循環路４１と第二の正極循環路３２とを切り替える第二切替部として、主往路配管３３ｂと共通往路配管３９ｂとが連通するように三方バルブ３９０ｂを切り替えると共に、共通復路配管３９ｄと主復路配管３５ｂとが連通するように三方バルブ３９０ｄを切り替える。 When a by-reactant is generated in the negative electrode cell 13, the second controller 92 controls the operation of the second switching unit so that the positive electrode electrolyte is circulated through the negative electrode cell 13. In this case, the second controller 92 serves as a second switching unit for switching between the first negative electrode circulation path 41 and the second positive electrode circulation path 32, and is a three-way switch so that the main outward piping 33b and the common outward piping 39b communicate with each other. Along with switching the valve 390b, the three-way valve 390d is switched so that the common return pipe 39d and the main return pipe 35b are communicated.
　実施形態１－２のＲＦ電池システム１によれば、実施形態１－１のＲＦ電池システム１と同様に、第二制御器９２によって第一切替部又は第二切替部の動作を制御することで、正極セル１２又は負極セル１３に逆極性の電解液を循環させることができる。実施形態１－２のＲＦ電池システム１は、正極セル１２及び負極セル１３につながる配管が往路と復路でそれぞれ１本である。そして、各セル１２、１３につながる配管に対応してバルブが４つである。よって、実施形態１－２のＲＦ電池システム１は、実施形態１－１のＲＦ電池システム１に比較して、バンク２の構成を簡易にし易い。 According to the RF battery system 1 of Embodiment 1-2, similarly to the RF battery system 1 of Embodiment 1-1, by controlling the operation of the first switching unit or the second switching unit by the second controller 92 , the positive electrode cell 12 or the negative electrode cell 13 can be circulated with electrolyte solutions of opposite polarities. In the RF battery system 1 of Embodiment 1-2, there is one pipe for each of the outward route and the return route, which are connected to the positive electrode cell 12 and the negative electrode cell 13 . There are four valves corresponding to the pipes connected to each cell 12 and 13 . Therefore, in the RF battery system 1 of Embodiment 1-2, it is easier to simplify the configuration of the bank 2 than in the RF battery system 1 of Embodiment 1-1.
　≪実施形態２≫
　実施形態２では、図６を参照して、上述した二つ目の形態を説明する。二つ目の形態では、短時間放電を行うことで副反応物を再溶解させる。二つ目の形態では、電池セル１０に可変抵抗部７１が設けられている。二つ目の形態では、制御器９は第三制御器９３を備える。 <<Embodiment 2>>
In Embodiment 2, the above-described second form will be described with reference to FIG. In the second mode, the side reactants are redissolved by performing a short-time discharge. In the second form, the battery cell 10 is provided with the variable resistance section 71 . In a second form the controller 9 comprises a third controller 93 .
　可変抵抗部７１は、電池セル１０を構成する正極セル１２と負極セル１３との間に設けられている。電池セル１０と可変抵抗部７１との間には図示しないスイッチが設けられている。このスイッチの切り替えによって、電池セル１０から可変抵抗部７１に放電が行われる。スイッチを用いずに、単に可変抵抗部７１の抵抗値の変更により放電開始と放電停止を行ってもよい。放電によって可変抵抗部７１に供給された電力は、抵抗発熱により消費される。電池セル１０から可変抵抗部７１に放電することで、電池セル１０のＳＯＣが低くなる。可変抵抗部７１の抵抗値に応じて電池セル１０のＳＯＣが変化する。 The variable resistance section 71 is provided between the positive electrode cell 12 and the negative electrode cell 13 that constitute the battery cell 10 . A switch (not shown) is provided between the battery cell 10 and the variable resistance section 71 . By switching this switch, the battery cell 10 discharges to the variable resistance section 71 . Discharge may be started and stopped simply by changing the resistance value of the variable resistance section 71 without using a switch. The electric power supplied to the variable resistance section 71 by the discharge is consumed by resistance heating. By discharging from the battery cell 10 to the variable resistance section 71, the SOC of the battery cell 10 is lowered. The SOC of the battery cell 10 changes according to the resistance value of the variable resistance section 71 .
　第三制御器９３は、電池セル１０に供給される電解液の入口側のＳＯＣと、電池セル１０から排出される電解液の出口側のＳＯＣとの差が１０％以上となる放電を行うように電力変換装置８を制御する。上記差が１０％以上となると、電池セル１０内の電解液のＳＯＣが特定状態となる。上記差は、大きいほど電池セル１０内の電解液のＳＯＣが特定状態となり易い。よって、上記差は、更に１６％以上、２０％以上、２４％以上、特に３０％以上であってもよい。ＲＦ電池システム１の使用上、上記差は１００％以下、更に９０％以下、８０％以下、特に７５％以下、７０％以下である。 The third controller 93 performs discharge so that the difference between the SOC on the inlet side of the electrolyte supplied to the battery cell 10 and the SOC on the outlet side of the electrolyte discharged from the battery cell 10 is 10% or more. to control the power conversion device 8. When the difference is 10% or more, the SOC of the electrolyte in the battery cell 10 is in a specific state. The larger the difference, the easier it is for the SOC of the electrolyte in the battery cell 10 to reach the specific state. Thus, said difference may also be 16% or more, 20% or more, 24% or more, in particular 30% or more. In use of the RF battery system 1, the above difference is 100% or less, further 90% or less, 80% or less, especially 75% or less, 70% or less.
　第三制御器９３は、短時間、例えば１０分以下で上記差が１０％以上となる放電を行うように電力変換装置８を制御する。短時間で電池セル１０内の副反応物を再溶解できるように、電流密度や電解液の流量を適宜選択できる。電流密度は、例えば、３００ｍＡ／ｃｍ２以上、４００ｍＡ／ｃｍ２以上、５００ｍＡ／ｃｍ２以上、特に６００ｍＡ／ｃｍ２以上である。電解液の流量は、例えば、４．０ｃｃ／ｍｉｎ／ｃｍ２以下、３．０ｃｃ／ｍｉｎ／ｃｍ２以下、２．０ｃｃ／ｍｉｎ／ｃｍ２以下、特に０．０ｃｃ／ｍｉｎ／ｃｍ２である。電解液の流量は、電池セル１０に流れる電解液量である。電解液の流量の単位は、「ｃｃ／ｍｉｎ／ｃｍ２」であり、電池セル１０内の電極１ｃｍ２あたりに１分間で流れる電解液の体積で示す。電解液の流量が０．０ｃｃ／ｍｉｎ／ｃｍ２であるとは、電池セル１０に電解液が流れないということであり、電解液を循環させていないことを意味する。電解液の流量に関する事項は後述の充電の場合も同様に適用される。 The third controller 93 controls the power conversion device 8 so as to discharge in a short period of time, for example, 10 minutes or less, so that the difference becomes 10% or more. The current density and the flow rate of the electrolytic solution can be appropriately selected so that the side reaction product in the battery cell 10 can be redissolved in a short period of time. The current density is, for example, 300 mA/cm 2 or higher, 400 mA/cm 2 or higher, 500 mA/cm 2 or higher, particularly 600 mA/cm 2 or higher. The flow rate of the electrolytic solution is, for example, 4.0 cc/min/cm 2 or less, 3.0 cc/min/cm 2 or less, 2.0 cc/min/cm 2 or less, particularly 0.0 cc/min/cm 2 or less. The flow rate of the electrolytic solution is the amount of electrolytic solution that flows into the battery cell 10 . The unit of the flow rate of the electrolytic solution is "cc/min/cm 2 ", which indicates the volume of the electrolytic solution that flows per 1 cm 2 of the electrode in the battery cell 10 for 1 minute. The fact that the flow rate of the electrolytic solution is 0.0 cc/min/cm 2 means that the electrolytic solution does not flow in the battery cell 10 and that the electrolytic solution is not circulated. Matters relating to the flow rate of the electrolyte also apply to charging, which will be described later.
　本例では、電解液の流量を２．０ｃｃ／ｍｉｎ／ｃｍ２以下とすると共に、可変抵抗部７１を高い抵抗値に設定し、電池セル１０から可変抵抗部７１に放電している。電池セル１０が可変抵抗部７１に放電することで、電池セル１０から排出される電解液の出口側のＳＯＣが低くなる。 In this example, the flow rate of the electrolytic solution is set to 2.0 cc/min/cm 2 or less, and the variable resistance section 71 is set to a high resistance value to discharge from the battery cell 10 to the variable resistance section 71 . As the battery cell 10 discharges to the variable resistance portion 71, the SOC of the electrolyte discharged from the battery cell 10 on the outlet side becomes low.
　ＲＦ電池システム１には、図示しない流量計が設けられている。流量計は、例えば正極電解液が流れる往路配管２４及び負極電解液が流れる往路配管２５に設けられている。流量計は、往路配管２４におけるポンプ２８（図１）よりも下流側、及び往路配管２５におけるポンプ２９（図１）よりも下流側に設けられている。電解液の流量は、ポンプの制御器によりポンプ２８，２９の出力を制御することで調整できる。第三制御器９３は、流量計で計測された結果に基づいて電力変換装置８を制御している。その他、電解液の流量は、例えば、モニタセル６１の開放電圧（ＯＣＶ）、電解液の温度、及びポンプ２８，２９の出力から演算することもできる。電解液の温度を測定する温度計は、例えば上記の流量計の配置位置と同じ位置に設けられる。 The RF battery system 1 is provided with a flow meter (not shown). The flowmeters are provided, for example, in the outward piping 24 through which the positive electrode electrolyte flows and the outward piping 25 through which the negative electrode electrolyte flows. The flowmeters are provided downstream of the pump 28 ( FIG. 1 ) in the outward piping 24 and downstream of the pump 29 ( FIG. 1 ) in the outward piping 25 . The flow rate of the electrolytic solution can be adjusted by controlling the outputs of the pumps 28 and 29 with the pump controller. The third controller 93 controls the power converter 8 based on the results measured by the flowmeter. In addition, the flow rate of the electrolytic solution can also be calculated from the open circuit voltage (OCV) of the monitor cell 61, the temperature of the electrolytic solution, and the outputs of the pumps 28 and 29, for example. A thermometer for measuring the temperature of the electrolytic solution is provided, for example, at the same position as the flowmeter described above.
　〔通常運転時〕
　ＲＦ電池システム１の通常運転時は、第三制御器９３により、可変抵抗部７１が低い抵抗値に設定されている。よって、ＲＦ電池システム１の通常運転時は、電池セル１０のＳＯＣは、メインＳＯＣの利用範囲を拡大した範囲内に制御されている。 [During normal operation]
During normal operation of the RF battery system 1, the third controller 93 sets the variable resistance section 71 to a low resistance value. Therefore, during normal operation of the RF battery system 1, the SOC of the battery cells 10 is controlled within a range expanded from the range of utilization of the main SOC.
　〔電解液の回復作業時〕
　バンク２の電解液の回復作業時は、第三制御器９３により、可変抵抗部７１が高い抵抗値に設定される。可変抵抗部７１の抵抗値は、上記差が１０％以上となる値に設定される。制御器９は、第一制御器９１により、電池セル１０のＳＯＣが特定状態で１０秒以上保持されるように電力変換装置８に指令を出す。具体的には、可変抵抗部７１において抵抗加熱がなされるような抵抗値に設定された状態で、電池セル１０に充電又は放電を１０秒以上行うように指令を出す。可変抵抗部７１の抵抗値に応じて電池セル１０は放電されることになる。この放電によって、電池セル１０の入口側のＳＯＣと出口側のＳＯＣとの差が１０％以上となる。 [During electrolyte recovery work]
During recovery work of the electrolytic solution in the bank 2, the third controller 93 sets the variable resistance section 71 to a high resistance value. The resistance value of the variable resistance section 71 is set to a value that makes the difference 10% or more. The controller 9 issues a command to the power conversion device 8 through the first controller 91 so that the SOC of the battery cell 10 is held in a specific state for 10 seconds or more. Specifically, a command is issued to charge or discharge the battery cell 10 for 10 seconds or more in a state where the resistance value is set so as to cause resistance heating in the variable resistance portion 71 . The battery cell 10 is discharged according to the resistance value of the variable resistance section 71 . Due to this discharge, the difference between the SOC on the inlet side and the SOC on the outlet side of the battery cell 10 becomes 10% or more.
　実施形態２のＲＦ電池システム１によれば、第三制御器９３によって電池セル１０のＳＯＣが低くなることで、電池セル１０内の電解液のＳＯＣを特定状態にできる。その結果、電池セル１０内に生成された副反応物を再溶解することができる。実施形態２のＲＦ電池システム１は、電池セル１０に可変抵抗部７１を配置し、その可変抵抗部７１の抵抗値を制御することで、電池セル１０内の電解液のＳＯＣを特定状態にできる。言い換えると、実施形態２のＲＦ電池システム１は、ＲＦ電池システム１の通常運転で使用される設備に簡易な改変を施して利用することで、電池セル１０内の電解液のＳＯＣを特定状態にできる。よって、実施形態２のＲＦ電池システム１は、実施形態１のＲＦ電池システム１に比較して、バンク２の構成を簡易にし易い。 According to the RF battery system 1 of Embodiment 2, the SOC of the battery cell 10 is lowered by the third controller 93, so that the SOC of the electrolyte in the battery cell 10 can be brought to a specific state. As a result, the side reactants generated in the battery cells 10 can be redissolved. The RF battery system 1 of Embodiment 2 can set the SOC of the electrolyte in the battery cell 10 to a specific state by arranging the variable resistance unit 71 in the battery cell 10 and controlling the resistance value of the variable resistance unit 71. . In other words, the RF battery system 1 of Embodiment 2 can be used by simply modifying equipment used in normal operation of the RF battery system 1 to set the SOC of the electrolyte in the battery cell 10 to a specific state. can. Therefore, in the RF battery system 1 of the second embodiment, compared to the RF battery system 1 of the first embodiment, it is easier to simplify the configuration of the bank 2 .
　≪実施形態３≫
　実施形態３では、図７を参照して、上述した三つ目の形態を説明する。三つ目の形態では、短時間充電を行うことで副反応物を再溶解させる。三つ目の形態では、電力変換装置８に第二電源７２が接続されている。三つ目の形態では、制御器９は第三制御器９３を備える。 <<Embodiment 3>>
Embodiment 3 describes the above-described third embodiment with reference to FIG. 7 . In the third mode, charging for a short period of time causes the side reactants to be redissolved. In a third form, a second power supply 72 is connected to the power conversion device 8 . In a third form, controller 9 comprises a third controller 93 .
　第二電源７２は、電力系統につながる電源８１０（図１）とは異なる電源である。第二電源７２には、二次電池等の各種蓄電手段が利用できる。第二電源７２は、電力変換装置８を介してバンク２に充電する。この充電によって電池セル１０のＳＯＣが変化する。 The second power supply 72 is a power supply different from the power supply 810 (Fig. 1) connected to the power system. Various power storage means such as a secondary battery can be used for the second power supply 72 . The second power supply 72 charges the bank 2 via the power conversion device 8 . This charging changes the SOC of the battery cell 10 .
　第三制御器９３は、電池セル１０に供給される電解液の入口側のＳＯＣと、電池セル１０から排出される電解液の出口側のＳＯＣとの差が１０％以上となる充電を行うように電力変換装置８を制御する。上記差が１０％以上となると、電池セル１０内の電解液のＳＯＣが特定状態となる。上記差は、大きいほど電池セル１０内の電解液のＳＯＣが特定状態となり易い。よって、上記差は、更に１６％以上、２０％以上、２４％以上、特に３０％以上であってもよい。ＲＦ電池システム１の使用上、上記差は１００％以下、更に９０％以下、８０％以下、特に７５％以下、７０％以下である。 The third controller 93 performs charging so that the difference between the SOC on the inlet side of the electrolyte supplied to the battery cell 10 and the SOC on the outlet side of the electrolyte discharged from the battery cell 10 is 10% or more. to control the power conversion device 8. When the difference is 10% or more, the SOC of the electrolyte in the battery cell 10 is in a specific state. The larger the difference, the easier it is for the SOC of the electrolyte in the battery cell 10 to reach the specific state. Thus, said difference may also be 16% or more, 20% or more, 24% or more, in particular 30% or more. In use of the RF battery system 1, the above difference is 100% or less, further 90% or less, 80% or less, especially 75% or less, 70% or less.
　第三制御器９３は、短時間、例えば１０分以下で上記差が１０％以上となる充電を行うように電力変換装置８を制御する。短時間で電池セル１０内の副反応物を再溶解できるように、電流密度や電解液の流量を適宜選択できる。充電では、電流密度は、例えば、３００ｍＡ／ｃｍ２以上、４００ｍＡ／ｃｍ２以上、５００ｍＡ／ｃｍ２以上、特に６００ｍＡ／ｃｍ２以上である。電解液の流量は、例えば、４．０ｃｃ／ｍｉｎ／ｃｍ２以下、３．０ｃｃ／ｍｉｎ／ｃｍ２以下、２．０ｃｃ／ｍｉｎ／ｃｍ２以下、特に０．０ｃｃ／ｍｉｎ／ｃｍ２である。電解液の流量が０．０ｃｃ／ｍｉｎ／ｃｍ２では、電解液は循環していない。 The third controller 93 controls the power conversion device 8 so as to perform charging in a short period of time, for example, 10 minutes or less, so that the difference becomes 10% or more. The current density and the flow rate of the electrolytic solution can be appropriately selected so that the side reaction product in the battery cell 10 can be redissolved in a short period of time. In charging, the current density is, for example, 300 mA/cm 2 or higher, 400 mA/cm 2 or higher, 500 mA/cm 2 or higher, especially 600 mA/cm 2 or higher. The flow rate of the electrolytic solution is, for example, 4.0 cc/min/cm 2 or less, 3.0 cc/min/cm 2 or less, 2.0 cc/min/cm 2 or less, particularly 0.0 cc/min/cm 2 or less. When the electrolyte flow rate is 0.0 cc/min/cm 2 , the electrolyte does not circulate.
　本例では、電解液の流量を２．０ｃｃ／ｍｉｎ／ｃｍ２以下とすると共に、電流密度を６００ｍＡ／ｃｍ２以上に設定し、第二電源７２から電力変換装置８を介してバンク２に短時間充電している。電池セル１０が第二電源７２から充電されることで、電池セル１０から排出される電解液の出口側のＳＯＣが高くなる。 In this example, the flow rate of the electrolytic solution is set to 2.0 cc/min/cm 2 or less, the current density is set to 600 mA/cm 2 or more, and the second power supply 72 is connected to the bank 2 via the power conversion device 8. charging time. By charging the battery cell 10 from the second power supply 72, the SOC at the outlet side of the electrolyte discharged from the battery cell 10 increases.
　〔通常運転時〕
　ＲＦ電池システム１の通常運転時は、第三制御器９３により、第二電源７２からバンク２の充電を行わないように制御されている。よって、ＲＦ電池システム１の通常運転時は、電池セル１０のＳＯＣは、メインＳＯＣの利用範囲を拡大した範囲内に制御されている。 [During normal operation]
During normal operation of the RF battery system 1 , the third controller 93 controls so as not to charge the bank 2 from the second power supply 72 . Therefore, during normal operation of the RF battery system 1, the SOC of the battery cells 10 is controlled within a range expanded from the range of utilization of the main SOC.
　〔電解液の回復作業時〕
　バンク２の電解液の回復作業時は、第三制御器９３により、第二電源７２から電力変換装置８を介してバンク２に充電される。第二電源７２からの充電は、上記差が１０％以上となるように行われる。 [During electrolyte recovery work]
During recovery work of the electrolyte in bank 2 , the bank 2 is charged from the second power supply 72 via the power conversion device 8 by the third controller 93 . Charging from the second power supply 72 is performed so that the difference is 10% or more.
　実施形態３のＲＦ電池システム１によれば、第三制御器９３によって電池セル１０のＳＯＣが高くなることで、電池セル１０内の電解液のＳＯＣを特定状態にできる。その結果、電池セル１０内に生成された副反応物を再溶解することができる。実施形態３のＲＦ電池システム１は、電力変換装置８に第二電源７２を接続し、その第二電源７２からバンク２の充電を制御することで、電池セル１０内の電解液のＳＯＣを特定状態にできる。言い換えると、実施形態３のＲＦ電池システム１は、ＲＦ電池システム１の通常運転で使用される設備に簡易な改変を施して利用することで、電池セル１０内の電解液のＳＯＣを特定状態にできる。 According to the RF battery system 1 of Embodiment 3, the SOC of the battery cell 10 is increased by the third controller 93, so that the SOC of the electrolyte in the battery cell 10 can be brought to a specific state. As a result, the side reactants generated in the battery cells 10 can be redissolved. The RF battery system 1 of Embodiment 3 connects the second power supply 72 to the power conversion device 8, and controls the charging of the bank 2 from the second power supply 72, thereby specifying the SOC of the electrolyte in the battery cell 10. state. In other words, the RF battery system 1 of Embodiment 3 can be used by simply modifying equipment used in normal operation of the RF battery system 1 to set the SOC of the electrolyte in the battery cell 10 to a specific state. can.
　ＲＦ電池システム１は、上述した実施形態１の構成、実施形態２の構成、及び実施形態３の構成の少なくとも一つを備える。ＲＦ電池システム１は、実施形態１の構成、実施形態２の構成、及び実施形態３の構成の全てを備えてもよい。 The RF battery system 1 has at least one of the configuration of the first embodiment, the configuration of the second embodiment, and the configuration of the third embodiment. The RF battery system 1 may have all of the configuration of the first embodiment, the configuration of the second embodiment, and the configuration of the third embodiment.
　≪実施形態４≫
　実施形態４では、図８を参照して、複数のバンク２を備えるＲＦ電池システム１を説明する。複数のバンク２は、通常運転に使用される第一のバンク２ａと、電解液の回復作業に使用される第二のバンク２ｂとを備える。制御器９は、輪番制御器９４を備える。 <<Embodiment 4>>
Embodiment 4 describes an RF battery system 1 including a plurality of banks 2 with reference to FIG. 8 . The plurality of banks 2 includes a first bank 2a used for normal operation and a second bank 2b used for electrolyte recovery work. The controller 9 comprises a rotation controller 94 .
　第一のバンク２ａは、外部の電源８１０や負荷８２０（図１）との間で充電及び放電を行うバンクである。第一のバンク２ａにおける電池セル１０のＳＯＣは、メインＳＯＣの利用範囲を拡大した範囲内に制御されている。第一のバンク２ａでは、電池セル１０内の電解液のＳＯＣは、正極タンク２２内の正極電解液のＳＯＣと実質的に同じであり、かつ負極タンク２３内の負極電解液のＳＯＣと実質的に同じである。第一のバンク２ａの数は、例えば、２以上、更に１０以上、特に１５以上である。第一のバンク２ａの数は、多いほどＲＦ電池システム１全体の電池容量が確保され易い。 The first bank 2a is a bank that performs charging and discharging between an external power source 810 and a load 820 (Fig. 1). The SOC of the battery cells 10 in the first bank 2a is controlled within an expanded range of the main SOC. In the first bank 2a, the SOC of the electrolyte in the battery cell 10 is substantially the same as the SOC of the cathode electrolyte in the cathode tank 22, and substantially the same as the SOC of the anode electrolyte in the anode tank 23. is the same as The number of first banks 2a is, for example, 2 or more, further 10 or more, particularly 15 or more. The larger the number of first banks 2a, the easier it is for the battery capacity of the entire RF battery system 1 to be secured.
　第二のバンク２ｂは、電解液の回復作業を行うバンクである。第二のバンク２ｂにおける電池セル１０のＳＯＣは、第一制御器９１により特定状態に制御される。つまり、第二のバンク２ｂにおける電池セル１０のＳＯＣは、電池セル１０内の電解液のＳＯＣが正極タンク２２内の正極電解液のＳＯＣと５％以上異なる状態、及び電池セル１０内の電解液のＳＯＣが負極タンク２３内の負極電解液のＳＯＣと５％以上異なる状態の少なくとも一方の状態で１０秒以上保持される。第二のバンク２ｂの数は第一のバンク２ａの数よりも少ない。例えば、複数のバンク２の合計数に対する第二のバンク２ｂの数の割合は３０％以下、更に２０％以下、特に１０％以下である。 The second bank 2b is a bank for recovering the electrolyte. The SOC of the battery cells 10 in the second bank 2b is controlled by the first controller 91 to a specific state. That is, the SOC of the battery cell 10 in the second bank 2b is a state in which the SOC of the electrolyte in the battery cell 10 differs from the SOC of the positive electrode electrolyte in the positive electrode tank 22 by 5% or more, and is held for 10 seconds or more in at least one state in which the SOC of the negative electrode electrolyte in the negative electrode tank 23 differs by 5% or more from the SOC of the negative electrode electrolyte. The number of second banks 2b is less than the number of first banks 2a. For example, the ratio of the number of the second banks 2b to the total number of the plurality of banks 2 is 30% or less, further 20% or less, particularly 10% or less.
　全バンク２の数は、例えば４以上である。バンク２の数が多いほど、ＲＦ電池システム１全体の電池容量を増加させることができる。バンク２の数は、更に１１以上、１６以上であってもよい。バンク２の数が多いと、システム全体が巨大化したり、バンク２の管理が煩雑化したりする。バンク２の数の上限は、例えば、１００以下、更に５０以下である。バンク２の数は、例えば１１以上１００以下、１６以上５０以下である。 The number of all banks 2 is, for example, 4 or more. As the number of banks 2 increases, the battery capacity of the entire RF battery system 1 can be increased. The number of banks 2 may be 11 or more, or 16 or more. If the number of banks 2 is large, the entire system becomes huge, and management of the banks 2 becomes complicated. The upper limit of the number of banks 2 is, for example, 100 or less, and further 50 or less. The number of banks 2 is, for example, 11 or more and 100 or less, or 16 or more and 50 or less.
　制御器９は、各バンク２の充電及び放電を独立して制御する。そのため、第一のバンク２ａで充電又は放電を行いながら、第二のバンク２ｂの電解液の回復作業を行うことが可能である。制御器９は、電源８１０や負荷８２０（図１）との間で充電又は放電を行う際に、各第一のバンク２ａの電力変換装置８に充電又は放電の指令を出す。第一のバンク２ａでは、要求された充電量又は放電量に応じて電池セル１０が充電又は放電を行う。制御器９は、第二のバンク２ｂの電力変換装置８に電解液の回復作業の指令を出す。第二のバンク２ｂでは、電源８１０や負荷８２０（図１）との間で電池セル１０が充電及び放電を行わず、電解液の回復作業が実行される。電解液の回復作業では、上述した実施形態１から実施形態３の手段を用いて、電池セル１０のＳＯＣを特定状態とする。図８では、説明の便宜上、セルスタック２００の一部のセルでモニタセル６０を構成しており、実施形態１から実施形態３で説明した循環路やバルブ、他のモニタセル等は省略している。 The controller 9 controls charging and discharging of each bank 2 independently. Therefore, it is possible to recover the electrolyte in the second bank 2b while charging or discharging the first bank 2a. When charging or discharging between the power source 810 and the load 820 (FIG. 1), the controller 9 issues a charging or discharging command to the power conversion device 8 of each first bank 2a. In the first bank 2a, the battery cells 10 are charged or discharged according to the requested charge amount or discharge amount. The controller 9 issues an electrolyte recovery operation command to the power conversion device 8 of the second bank 2b. In the second bank 2b, the battery cells 10 are not charged or discharged between the power source 810 and the load 820 (FIG. 1), and the recovery work of the electrolyte is performed. In the recovery work of the electrolyte, the SOC of the battery cell 10 is set to a specific state using the means of the first to third embodiments described above. In FIG. 8, for convenience of explanation, some cells of the cell stack 200 constitute the monitor cell 60, and the circulation paths, valves, and other monitor cells described in the first to third embodiments are omitted.
　本例の制御器９は輪番制御器９４を備える。輪番制御器９４は、複数のバンク２が順番に電池セル１０の状態が特定状態となるように電力変換装置８を制御する。言い換えると、輪番制御器９４は、複数のバンク２の各々について、通常運転を行う第一のバンク２ａとなる時間帯と、電解液の回復作業を行う第二のバンク２ｂとなる時間帯とを含むように電力変換装置８を制御する。輪番制御器９４では、例えば、複数のバンク２の合計数を１１とした場合、以下のように制御される。それぞれのバンク２をＮｏ．１、Ｎｏ．２・・・Ｎｏ．１１とする。ある時間において、複数のバンク２のうち、Ｎｏ．１からＮｏ．１０が第一のバンク２ａであり、残りのＮｏ．１１が第二のバンク２ｂであるとする。定期的に各バンク２を順番に第二のバンク２ｂに切り替えるとする。所定時間経過したとき、Ｎｏ．１１を第二のバンク２ｂから第一のバンク２ａに切り替える。Ｎｏ．１１に代えて、Ｎｏ．１、Ｎｏ．２・・・Ｎｏ．１０のうちのいずれかを第一のバンク２ａから第二のバンク２ｂに切り替える。ここでは、Ｎｏ．１０を第二のバンク２ｂに切り替える。このとき、Ｎｏ．１０を除く、Ｎｏ．１からＮｏ．９とＮｏ．１１が第一のバンク２ａとなる。第一のバンク２ａの数及び第二のバンク２ｂの数は変化しない。更に所定時間経過したとき、Ｎｏ．１０を第一のバンク２ａに切り替えると共に、Ｎｏ．９を第二のバンク２ｂに切り替える。このように、時間の経過にしたがって、Ｎｏ．１１→Ｎｏ．１０→Ｎｏ．９→・・・Ｎｏ．１→Ｎｏ．１１→・・・というように順番に第二のバンク２ｂから第一のバンク２ａに切り替えることで、複数の全てのバンク２を輪番で電解液の回復作業することができる。 The controller 9 of this example includes a rotation controller 94 . The rotation controller 94 controls the power conversion device 8 so that the states of the battery cells 10 of the plurality of banks 2 are in a specific state in order. In other words, for each of the plurality of banks 2, the rotatable controller 94 selects a time zone for the first bank 2a during normal operation and a time zone for the second bank 2b during the recovery work of the electrolyte. Control the power conversion device 8 to include. In the rotation controller 94, for example, when the total number of the plurality of banks 2 is 11, the following control is performed. Let each bank 2 be No. 1, No. 2...No. 11. At a certain time, among the plurality of banks 2, No. 1 to No. 10 is the first bank 2a, and the remaining No. 11 is the second bank 2b. Suppose that periodically each bank 2 is switched to the second bank 2b in turn. When a predetermined time has passed, No. 11 is switched from the second bank 2b to the first bank 2a. No. 11, no. 1, No. 2...No. 10 from the first bank 2a to the second bank 2b. Here, No. 10 to the second bank 2b. At this time, No. Except for 10, no. 1 to No. 9 and No. 11 is the first bank 2a. The number of first banks 2a and the number of second banks 2b remain unchanged. Further, when a predetermined time has passed, No. 10 to the first bank 2a, and No. 9 to the second bank 2b. In this way, as time passes, No. 11→No. 10→No. 9→No. 1→No. By switching from the second bank 2b to the first bank 2a in order such as 11→ .
　複数のバンク２を備える場合、第三制御器９３では、以下の制御を行うことができる。一つ目の制御として、上述した短時間放電を行って電解液の回復作業を行う場合、第三制御器９３は、第二のバンク２ｂの放電電力で第一のバンク２ａを充電するように制御してもよい。この場合、実施形態２で用いた可変抵抗部７１を用いることなく、第二のバンク２ｂの電池セル１０内の電解液のＳＯＣを特定状態にできる。二つ目の制御として、上述した短時間充電を行って電解液の回復作業を行う場合、第三制御器９３は、第一のバンク２ａの放電電力で第二のバンク２ｂを充電するように制御してもよい。この場合、実施形態３で用いた第二電源７２を用いることなく、第二のバンク２ｂの電池セル１０内の電解液のＳＯＣを特定状態にできる。 When a plurality of banks 2 are provided, the third controller 93 can perform the following controls. As the first control, when performing the above-described short-time discharge to recover the electrolyte, the third controller 93 charges the first bank 2a with the discharge power of the second bank 2b. may be controlled. In this case, the SOC of the electrolyte in the battery cells 10 of the second bank 2b can be set to a specific state without using the variable resistance section 71 used in the second embodiment. As the second control, when performing the above-described short-time charging to recover the electrolyte, the third controller 93 charges the second bank 2b with the discharged power of the first bank 2a. may be controlled. In this case, the SOC of the electrolyte in the battery cells 10 of the second bank 2b can be brought to a specific state without using the second power supply 72 used in the third embodiment.
　実施形態４のＲＦ電池システム１によれば、輪番制御器９４によって、外部の電源８１０や負荷８２０（図１）につながる電力系統との充電又は放電と同一時間帯において、第二のバンク２ｂの電池セル１０内の電解液のＳＯＣを特定状態として電解液の回復作業を行うことができる。つまり、実施形態４のＲＦ電池システム１によれば、ＲＦ電池システム１の通常運転を停止することなく、電解液の回復作業を行うことができる。 According to the RF battery system 1 of Embodiment 4, the rotation controller 94 allows the second bank 2b to The recovery operation of the electrolyte can be performed with the SOC of the electrolyte in the battery cell 10 set to a specific state. That is, according to the RF battery system 1 of Embodiment 4, the recovery work of the electrolytic solution can be performed without stopping the normal operation of the RF battery system 1 .
　［試験例１］
　試験例１では、高ＳＯＣ領域で正極セルに副反応物が生成されたバンクにおいて、その副反応物を再溶解する電解液の回復作業を行うことによるバンクの電池性能の改善について調べた。本例では、複数の電池セルを備えるＲＦ電池システムで試験を行った。 [Test Example 1]
In Test Example 1, in a bank in which a side reaction product was generated in a positive electrode cell in a high SOC region, the improvement of the battery performance of the bank was examined by performing an electrolyte recovery operation for redissolving the side reaction product. In this example, an RF battery system with multiple battery cells was tested.
　＜試験体１－１＞
　試験体１－１は、高ＳＯＣ領域で正極セルに副反応物が生成された状態のバンクである。試験体１－１では、副反応物を再溶解する電解液の回復作業を行っていない。 <Test body 1-1>
Specimen 1-1 is a bank in which a side reaction product is generated in the positive electrode cell in the high SOC region. In the specimen 1-1, the recovery work of the electrolytic solution for redissolving the by-reactants was not performed.
　＜試験体１－２＞
　試験体１－２では、高ＳＯＣ領域で正極セルに副反応物が生成された状態のバンクに対して、正極セルに負極電解液を循環させて、副反応物を再溶解する電解液の回復作業を行った。正極セルへの負極電解液の循環は、実施形態１－１で説明したように、第二制御器により第一切替部の動作を制御して、第一の正極循環路と第二の負極循環路とを切り替えた（図２及び図３も参照）。正極セルへの負極電解液の循環は３０秒行った。この逆極性の電解液の循環を３０秒行った後の電池セル内の電解液の充電状態は、正極タンク内の正極電解液の充電状態と１５８％異なっていた。つまり、試験体１－２では、電池セル内の電解液の充電状態が正極タンク内の正極電解液の充電状態と５％以上異なる特定状態が１０秒以上保持されていた。正極タンク内の正極電解液の充電状態は７９％だった。逆極性の電解液を循環させた場合、電池セル内の電解液の充電状態と、正極タンク内の正極電解液の充電状態との差は、正極電解液の充電状態から見た負極電解液の充電状態から求められる。 <Test body 1-2>
In test sample 1-2, the negative electrode electrolyte is circulated to the positive electrode cell for the bank in which the by-reactant is generated in the positive electrode cell in the high SOC region, and the electrolyte is recovered by re-dissolving the by-reactant. did the work. As described in Embodiment 1-1, the circulation of the negative electrode electrolyte to the positive electrode cell is performed by controlling the operation of the first switching unit by the second controller to switch the first positive electrode circulation path and the second negative electrode circulation. (see also Figures 2 and 3). The circulation of the negative electrode electrolyte to the positive electrode cell was performed for 30 seconds. The state of charge of the electrolyte in the battery cell after circulating the reverse polarity electrolyte for 30 seconds was 158% different from the state of charge of the positive electrode electrolyte in the positive electrode tank. That is, in the test sample 1-2, the specific state in which the state of charge of the electrolyte in the battery cell differs from the state of charge of the positive electrode electrolyte in the positive electrode tank by 5% or more was maintained for 10 seconds or longer. The state of charge of the positive electrode electrolyte in the positive electrode tank was 79%. When electrolytes of opposite polarities are circulated, the difference between the state of charge of the electrolyte in the battery cell and the state of charge of the positive electrode electrolyte in the positive electrode tank is the negative electrode electrolyte viewed from the state of charge of the positive electrode electrolyte. It is obtained from the state of charge.
　＜試験体１－３＞
　試験体１－３では、高ＳＯＣ領域で正極セルに副反応物が生成された状態のバンクに対して放電を行い、副反応物を再溶解する電解液の回復作業を行った。試験体１－３では、実施形態４で説明したように、複数のバンクを設け、第三制御器により電解液の回復作業を行う当該バンクの放電電力で通常運転に使用されるバンクを充電した。放電条件は以下とした。電池セルに循環される電解液の流量が１．６ｃｃ／ｍｉｎ／ｃｍ２である。電池セルの電流密度が６７０ｍＡ／ｃｍ２である。放電時間が３０秒である。電池セルに供給される電解液の入口側の充電状態と、電池セルから排出される電解液の出口側の充電状態との差が２０％である。このとき、電池セル内の電解液の充電状態は、正極タンク内の正極電解液の充電状態と１０％異なっていた。つまり、試験体１－３では、電池セル内の電解液の充電状態が正極タンク内の正極電解液の充電状態と５％以上異なる特定状態が１０秒以上保持されていた。正極タンク内の正極電解液の充電状態は７９％だった。電池セル内の電解液の充電状態は、電池セル内の電解液の充電状態の平均値である。 <Test body 1-3>
In the test sample 1-3, discharge was performed to the bank in which the side reaction product was generated in the positive electrode cell in the high SOC region, and the recovery work of the electrolytic solution was performed by redissolving the side reaction product. In test sample 1-3, as described in Embodiment 4, a plurality of banks were provided, and the banks used for normal operation were charged with the discharge power of the banks in which the recovery work of the electrolyte was performed by the third controller. . The discharge conditions were as follows. The flow rate of the electrolyte circulating in the battery cells is 1.6 cc/min/cm 2 . The current density of the battery cell is 670 mA/cm 2 . The discharge time is 30 seconds. The difference between the state of charge on the inlet side of the electrolyte supplied to the battery cell and the state of charge on the outlet side of the electrolyte discharged from the battery cell is 20%. At this time, the state of charge of the electrolyte in the battery cell was 10% different from the state of charge of the positive electrode electrolyte in the positive electrode tank. That is, in the test sample 1-3, the specific state in which the state of charge of the electrolyte in the battery cell differs from the state of charge of the positive electrode electrolyte in the positive electrode tank by 5% or more was maintained for 10 seconds or longer. The state of charge of the positive electrode electrolyte in the positive electrode tank was 79%. The state of charge of the electrolyte in the battery cell is the average value of the state of charge of the electrolyte in the battery cell.
　＜電池セルのＳＯＣ＞
　各試験体のバンクに対して充電を行い、電池セルを予め設定した電圧まで充電したときの電池セルのＳＯＣを測定した。充電条件は以下とした。電池セルに循環される電解液の流量が１．６ｃｃ／ｍｉｎ／ｃｍ２である。電池セルの電流密度が２５６ｍＡ／ｃｍ２である。その結果を表１に示す。表１では、電池セルを上記の予め設定した電圧まで充電したときの電池セルのＳＯＣを「充電末ＳＯＣ」と記す。 <SOC of battery cell>
The bank of each test body was charged, and the SOC of the battery cell was measured when the battery cell was charged to a preset voltage. The charging conditions were as follows. The flow rate of the electrolyte circulating in the battery cells is 1.6 cc/min/cm 2 . The current density of the battery cell is 256 mA/cm 2 . Table 1 shows the results. In Table 1, the SOC of the battery cell when the battery cell is charged to the preset voltage is referred to as "end of charge SOC".
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、電解液の回復作業を行った試験体１－２及び試験体１－３は、電解液の回復作業を行っていない試験体１－１に比較して、電池セルのＳＯＣが改善することがわかった。特に、副反応物が生成された正極セルに逆極性の電解液を循環させる電解液の回復作業を行った試験体１－２は、試験体１－１に比較して、電池セルのＳＯＣが約１０％も改善されることがわかった。 As shown in Table 1, the test specimens 1-2 and 1-3 subjected to the recovery work of the electrolyte have a higher battery cell capacity than the test specimen 1-1 which has not been subjected to the recovery work of the electrolyte. It was found that the SOC was improved. In particular, Test Specimen 1-2, which was subjected to the electrolyte recovery work of circulating the reverse polarity electrolyte in the positive electrode cell in which the side reaction product was generated, had a battery cell SOC lower than that of Test Specimen 1-1. An improvement of about 10% was found.
　［試験例２］
　試験例２では、高ＳＯＣ領域で正極セルに副反応物が生成された状態のバンクに対して放電を行って副反応物を再溶解する電解液の回復作業を行うにあたり、放電時間を変えた。つまり、試験例２では、電池セルの充電状態が特定状態に保持される時間を変えた。 [Test Example 2]
In Test Example 2, the discharge time was changed in order to recover the electrolytic solution by discharging the bank in which the side reaction product was generated in the positive electrode cell in the high SOC region and redissolving the side reaction product. . That is, in Test Example 2, the time for which the state of charge of the battery cell is maintained in the specific state was changed.
　＜試験体２－１＞
　試験体２－１は、高ＳＯＣ領域で正極セルに副反応物が生成された状態のバンクである。試験体２－１では、副反応物を再溶解する電解液の回復作業を行っていない。 <Test body 2-1>
Specimen 2-1 is a bank in which a side reaction product is generated in the positive electrode cell in the high SOC region. The specimen 2-1 was not subjected to the recovery work of the electrolytic solution for redissolving the by-reactants.
　＜試験体２－２、試験体２－３、試験体２－４＞
　試験体２－２、試験体２－３、及び試験体２－４では、高ＳＯＣ領域で正極セルに副反応物が生成された状態のバンクに対して放電を行い、副反応物を再溶解する電解液の回復作業を行った。いずれの試験体も、実施形態４で説明したように、複数のバンクを設け、第三制御器により電解液の回復作業を行う当該バンクの放電電力で通常運転に使用されるバンクを充電した。各試験体の放電条件は、放電時間以外の条件を同じとした。電池セルに循環される電解液の流量が０．９６ｃｃ／ｍｉｎ／ｃｍ２である。電池セルの電流密度が６７０ｍＡ／ｃｍ２である。電池セルに供給される電解液の入口側の充電状態と、電池セルから排出される電解液の出口側の充電状態との差が３３％である。各試験体における放電時間は以下とした。試験体２－２が３０秒である。試験体２－３が６０秒である。試験体２－４が１２０秒である。いずれの試験体も、電池セル内の電解液の充電状態は、正極タンク内の正極電解液の充電状態と１６．５％異なっていた。つまり、試験体２－２、試験体２－３、及び試験体２－４では、電池セル内の電解液の充電状態が正極タンク内の正極電解液の充電状態と５％以上異なる特定状態に保持されていた。いずれの試験体も、正極タンク内の正極電解液の充電状態は６８％だった。 <Test body 2-2, test body 2-3, test body 2-4>
In the test specimens 2-2, 2-3, and 2-4, the bank in which the side reaction is generated in the positive electrode cell in the high SOC region is discharged to redissolve the side reaction. The recovery work of the electrolyte was carried out. Each test sample was provided with a plurality of banks as described in the fourth embodiment, and the banks used for normal operation were charged with the discharge power of the banks in which the recovery work of the electrolytic solution was performed by the third controller. The discharge conditions for each specimen were the same except for the discharge time. The flow rate of electrolyte circulating in the battery cells is 0.96 cc/min/cm 2 . The current density of the battery cell is 670 mA/cm 2 . The difference between the state of charge at the inlet side of the electrolyte supplied to the battery cell and the state of charge at the outlet side of the electrolyte discharged from the battery cell is 33%. The discharge time for each specimen was as follows. Specimen 2-2 is 30 seconds. Specimen 2-3 is 60 seconds. Specimens 2-4 are 120 seconds. In all test specimens, the state of charge of the electrolyte in the battery cell was different from the state of charge of the positive electrode electrolyte in the positive electrode tank by 16.5%. That is, in the test specimens 2-2, 2-3, and 2-4, the state of charge of the electrolyte in the battery cell is different from the state of charge of the positive electrode electrolyte in the positive electrode tank by 5% or more. was held. In both specimens, the state of charge of the positive electrode electrolyte in the positive electrode tank was 68%.
　＜電池セルのＳＯＣ＞
　各試験体のバンクに対して充電を行い、電池セルを予め設定した電圧まで充電したときの電池セルのＳＯＣを測定した。充電条件は以下とした。電池セルに循環される電解液の流量が０．９６ｃｃ／ｍｉｎ／ｃｍ２である。電池セルの電流密度が２５６ｍＡ／ｃｍ２である。その結果を表２に示す。表２では、電池セルを上記の予め設定した電圧まで充電したときの電池セルのＳＯＣを「充電末ＳＯＣ」と記す。 <SOC of battery cell>
The bank of each test body was charged, and the SOC of the battery cell was measured when the battery cell was charged to a preset voltage. The charging conditions were as follows. The flow rate of electrolyte circulating in the battery cells is 0.96 cc/min/cm 2 . The current density of the battery cell is 256 mA/cm 2 . Table 2 shows the results. In Table 2, the SOC of the battery cell when the battery cell is charged to the preset voltage is referred to as "end of charge SOC".
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２に示すように、放電時間を長くする、つまり電池セルの充電状態が特定状態に保持される時間を長くすることで、電池セルのＳＯＣをより改善できることがわかった。特に、放電時間が３０秒以上と長くなることで、電池セルのＳＯＣをより改善できることがわかった。放電時間が６０秒を超えると、電池セルのＳＯＣの改善率の割合が微小となることがわかった。よって、放電時間が１０分以下という短時間であっても、電池セル内で生成した副反応物を再溶解することができると期待できる。 As shown in Table 2, it was found that the SOC of the battery cell can be further improved by lengthening the discharge time, that is, by lengthening the time during which the state of charge of the battery cell is held in a specific state. In particular, it was found that the SOC of the battery cell can be further improved by increasing the discharge time to 30 seconds or longer. It was found that when the discharge time exceeded 60 seconds, the rate of improvement in the SOC of the battery cell was very small. Therefore, even if the discharge time is as short as 10 minutes or less, it can be expected that the side reaction products generated in the battery cells can be redissolved.
　［試験例３］
　試験例３では、高ＳＯＣ領域で正極セルに副反応物が生成された状態のバンクに対して放電を行って副反応物を再溶解する電解液の回復作業を行うにあたり、ＳＯＣの差を変えた。ＳＯＣの差は、電池セルに供給される電解液の入口側の充電状態と、電池セルから排出される電解液の出口側の充電状態との差である。つまり、試験例３では、電池セルの充電状態を特定状態の範囲内で変えた。 [Test Example 3]
In Test Example 3, the difference in SOC was changed in performing the recovery work of the electrolytic solution for redissolving the side reaction by discharging the bank in which the side reaction was generated in the positive electrode cell in the high SOC region. rice field. The difference in SOC is the difference between the state of charge on the inlet side of the electrolyte supplied to the battery cell and the state of charge on the outlet side of the electrolyte discharged from the battery cell. That is, in Test Example 3, the state of charge of the battery cells was changed within the range of the specific state.
　＜試験体３－１＞
　試験体３－１は、高ＳＯＣ領域で正極セルに副反応物が生成された状態のバンクである。試験体３－１では、副反応物を再溶解する電解液の回復作業を行っていない。 <Test body 3-1>
Specimen 3-1 is a bank in which a side reaction product is generated in the positive electrode cell in the high SOC region. In the specimen 3-1, the recovery work of the electrolytic solution for redissolving the by-reactants was not performed.
　＜試験体３－２、試験体３－３、試験体３－４＞
　試験体３－２、試験体３－３、及び試験体３－４では、高ＳＯＣ領域で正極セルに副反応物が生成された状態のバンクに対して放電を行い、副反応物を再溶解する電解液の回復作業を行った。いずれの試験体も、実施形態４で説明したように、複数のバンクを設け、第三制御器により電解液の回復作業を行う当該バンクの放電電力で通常運転に使用されるバンクを充電した。各試験体の放電条件は表３に示す。いずれの試験体も放電時間は３０秒とした。つまり、試験体３－２、試験体３－３、及び試験体３－４では、電池セル内の電解液の充電状態が特定状態の範囲内で１０秒以上保持されていた。いずれの試験体も、正極タンク内の正極電解液の充電状態は６８％だった。 <Test body 3-2, test body 3-3, test body 3-4>
In test specimens 3-2, 3-3, and 3-4, discharge is performed on the bank in which the side reaction product is generated in the positive electrode cell in the high SOC region, and the side reaction product is redissolved. The recovery work of the electrolyte was carried out. Each test sample was provided with a plurality of banks as described in the fourth embodiment, and the banks used for normal operation were charged with the discharge power of the banks in which the recovery work of the electrolytic solution was performed by the third controller. Table 3 shows the discharge conditions for each specimen. The discharge time was set to 30 seconds for all specimens. That is, in the test samples 3-2, 3-3, and 3-4, the state of charge of the electrolyte in the battery cells was maintained within the specific state range for 10 seconds or longer. In both specimens, the state of charge of the positive electrode electrolyte in the positive electrode tank was 68%.
　＜電池セルのＳＯＣ＞
　各試験体のバンクに対して充電を行い、電池セルを予め設定した電圧まで充電したときの電池セルのＳＯＣを測定した。充電条件は以下とした。電池セルに循環される電解液の流量が０．９６ｃｃ／ｍｉｎ／ｃｍ２である。電池セルの電流密度が２５６ｍＡ／ｃｍ２である。その結果を表３に示す。表３では、電池セルを上記の予め設定した電圧まで充電したときの電池セルのＳＯＣを「充電末ＳＯＣ」と記す。 <SOC of battery cell>
The bank of each test body was charged, and the SOC of the battery cell was measured when the battery cell was charged to a preset voltage. The charging conditions were as follows. The flow rate of electrolyte circulating in the battery cells is 0.96 cc/min/cm 2 . The current density of the battery cell is 256 mA/cm 2 . Table 3 shows the results. In Table 3, the SOC of the battery cell when the battery cell is charged to the preset voltage is referred to as "end of charge SOC".
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表３に示すように、ＳＯＣの差を大きくすることで、電池セルのＳＯＣをより改善できることがわかった。特に、ＳＯＣの差が３０％以上、３３％以上、更に４５％以上であることで、電池セルのＳＯＣをより改善できることがわかった。ＳＯＣの差が４８％を超えると、電池セルのＳＯＣの改善率の割合が微小となることがわかった。よって、ＳＯＣの差が１０％以上５０％以下となるように放電することで、電池セル内で生成した副反応物を再溶解することができると期待できる。 As shown in Table 3, it was found that the SOC of the battery cells can be further improved by increasing the difference in SOC. In particular, it has been found that the SOC of the battery cells can be further improved when the SOC difference is 30% or more, 33% or more, and further 45% or more. It was found that when the difference in SOC exceeds 48%, the rate of improvement in the SOC of the battery cell becomes very small. Therefore, it can be expected that by discharging so that the difference in SOC is 10% or more and 50% or less, it is possible to re-dissolve the side reaction product generated in the battery cell.
　１　レドックスフロー電池システム（ＲＦ電池システム）
　２　バンク、２ａ　第一のバンク、２ｂ　第二のバンク
　１０　電池セル
　１１　隔膜
　１２　正極セル、１３　負極セル
　１４　正極電極、１５　負極電極
　２２　正極タンク、２３　負極タンク
　２４、２５　往路配管、２６、２７　復路配管
　２８、２９　ポンプ
　３１　第一の正極循環路、３２　第二の正極循環路
　３３、３３ａ、３３ｂ　主往路配管、３４ａ、３４ｂ　分岐往路配管
　３５、３５ａ、３５ｂ　主復路配管、３６ａ、３６ｂ　分岐復路配管
　３７ａ、３７ｂ、３８ａ、３８ｂ　バルブ
　３９ａ、３９ｂ　共通往路配管、３９ｃ、３９ｄ　共通復路配管
　３９０ａ、３９０ｂ　三方バルブ、３９０ｃ、３９０ｄ　三方バルブ
　４１　第一の負極循環路、４２　第二の負極循環路
　４３、４３ａ、４３ｂ　主往路配管、４４ａ、４４ｂ　分岐往路配管
　４５、４５ａ、４５ｂ　主復路配管、４６ａ、４６ｂ　分岐復路配管
　４７ａ、４７ｂ、４８ａ、４８ｂ　バルブ
　６０、６１　モニタセル
　７１　可変抵抗部、７２　第二電源
　８　電力変換装置
　９　制御器
　９０　基本制御器
　９１　第一制御器、９２　第二制御器、９３　第三制御器、９４　輪番制御器
　１００　セルフレーム、１１０　枠体、１１２　双極板、１５０　シール部材
　２００　セルスタック、　２０１　エンドプレート、２０２　締付部材
　８００　変電設備、８１０　電源、８２０　負荷 1 Redox flow battery system (RF battery system)
2 bank 2a first bank 2b second bank 10 battery cell 11 diaphragm 12 positive electrode cell 13 negative electrode cell 14 positive electrode 15 negative electrode 22 positive electrode tank 23 negative electrode tank 24, 25 outbound pipe 26, 27 return route Piping 28, 29 Pump 31 First positive electrode circulation path 32 Second positive electrode circulation path 33, 33a, 33b Main outward piping 34a, 34b Branch outward piping 35, 35a, 35b Main return piping 36a, 36b Branch return piping 37a, 37b, 38a, 38b valves 39a, 39b common outward piping, 39c, 39d common return piping 390a, 390b three-way valve, 390c, 390d three-way valve 41 first negative electrode circulation path 42 second negative electrode circulation path 43, 43a , 43b main outbound pipe 44a, 44b branch outbound pipe 45, 45a, 45b main return pipe 46a, 46b branch return pipe 47a, 47b, 48a, 48b valve 60, 61 monitor cell 71 variable resistor 72 second power supply 8 electric power Conversion device 9 controller 90 basic controller 91 first controller, 92 second controller, 93 third controller, 94 rotary controller 100 cell frame, 110 frame, 112 bipolar plate, 150 sealing member 200 cell stack, 201 end plate, 202 tightening member 800 transformer equipment, 810 power source, 820 load

Claims (8)

  1. 　バンクと、
    　前記バンクの充電状態を制御する制御器と、を備え、
    　前記バンクは、
    　　電池セルと、
    　　前記電池セルに循環される正極電解液が貯留された正極タンクと、
    　　前記電池セルに循環される負極電解液が貯留された負極タンクと、
    　　前記電池セルの充電及び放電を制御する電力変換装置とを備え、
    　前記制御器は、前記電池セルの充電状態が特定状態で１０秒以上保持されるように前記電力変換装置を制御する第一制御器を備え、
    　前記特定状態は、第一状態及び第二状態の少なくとも一方の状態であり、
    　前記第一状態は、前記電池セル内の電解液の充電状態が前記正極タンク内の正極電解液の充電状態と５％以上異なる状態であり、
    　前記第二状態は、前記電池セル内の電解液の充電状態が前記負極タンク内の負極電解液の充電状態と５％以上異なる状態である、
    　レドックスフロー電池システム。     bank and
    a controller that controls the state of charge of the bank;
    The bank is
    a battery cell;
    a positive electrode tank in which a positive electrode electrolyte circulating in the battery cell is stored;
    a negative electrode tank in which a negative electrode electrolyte circulating in the battery cell is stored;
    A power conversion device that controls charging and discharging of the battery cell,
    The controller comprises a first controller that controls the power conversion device so that the state of charge of the battery cell is held in a specific state for 10 seconds or more,
    The specific state is at least one of a first state and a second state,
    The first state is a state in which the state of charge of the electrolyte in the battery cell differs from the state of charge of the positive electrode electrolyte in the positive electrode tank by 5% or more,
    The second state is a state in which the state of charge of the electrolyte in the battery cell differs from the state of charge of the negative electrode electrolyte in the negative electrode tank by 5% or more.
    Redox flow battery system.
  2. 　前記特定状態が１０分以下保持される、請求項１に記載のレドックスフロー電池システム。 The redox flow battery system according to claim 1, wherein the specific state is maintained for 10 minutes or less.
  3. 　前記電池セルは、正極セルと負極セルとを備え、
    　前記正極電解液を前記正極タンクから前記正極セルを介して前記正極タンクに戻す第一の正極循環路と、
    　前記負極電解液を前記負極タンクから前記負極セルを介して前記負極タンクに戻す第一の負極循環路と、
    　前記正極電解液を前記正極タンクから前記負極セルを介して前記正極タンクに戻す第二の正極循環路及び前記負極電解液を前記負極タンクから前記正極セルを介して前記負極タンクに戻す第二の負極循環路の少なくとも一方の循環路と、
    　前記第一の正極循環路と前記第二の負極循環路とを切り替える第一切替部及び前記第一の負極循環路と前記第二の正極循環路とを切り替える第二切替部の少なくとも一方の切替部と、を有し、
    　前記制御器は、前記第一切替部又は前記第二切替部の動作を制御する第二制御器を備える、請求項１又は請求項２に記載のレドックスフロー電池システム。     The battery cell includes a positive electrode cell and a negative electrode cell,
    a first positive electrode circuit for returning the positive electrode electrolyte from the positive electrode tank to the positive electrode tank through the positive electrode cell;
    a first negative electrode circulation path returning the negative electrode electrolyte from the negative electrode tank to the negative electrode tank through the negative electrode cell;
    a second positive electrode circuit for returning the positive electrode electrolyte from the positive electrode tank to the positive electrode tank via the negative electrode cell; and a second positive electrode circuit for returning the negative electrode electrolyte from the negative electrode tank to the negative electrode tank via the positive electrode cell. at least one of the negative electrode circuits;
    Switching of at least one of a first switching unit for switching between the first positive electrode circuit and the second negative electrode circuit and a second switching unit for switching between the first negative electrode circuit and the second positive electrode circuit and
    The redox flow battery system according to claim 1 or 2, wherein the controller comprises a second controller that controls operation of the first switching unit or the second switching unit.
  4. 　前記制御器は、前記電池セルに供給される電解液の入口側の充電状態と、前記電池セルから排出される前記電解液の出口側の充電状態との差が１０％以上となる充電又は放電を行うように前記電力変換装置を制御する第三制御器を備える、請求項１又は請求項２に記載のレドックスフロー電池システム。 The controller performs charging or discharging such that the difference between the charged state at the inlet side of the electrolyte supplied to the battery cell and the charged state at the outlet side of the electrolyte discharged from the battery cell is 10% or more. 3. The redox flow battery system of claim 1 or claim 2, comprising a third controller that controls the power converter to perform
  5. 　前記第三制御器は、３００ｍＡ／ｃｍ２以上の電流密度で前記充電又は前記放電を行うように前記電力変換装置を制御する、請求項４に記載のレドックスフロー電池システム。 5. The redox flow battery system according to claim 4, wherein said third controller controls said power conversion device to perform said charging or said discharging at a current density of 300 mA/cm< 2 > or higher.
  6. 　前記第三制御器は、前記電池セルに供給される前記電解液の流量が４．０ｃｃ／ｍｉｎ／ｃｍ２以下であるときに前記充電又は前記放電を行うように前記電力変換装置を制御する、請求項４又は請求項５に記載のレドックスフロー電池システム。 The third controller controls the power conversion device to perform the charging or the discharging when the flow rate of the electrolyte supplied to the battery cell is 4.0 cc/min/cm 2 or less. The redox flow battery system according to claim 4 or 5.
  7. 　前記第一状態は、前記電池セル内の電解液の充電状態が前記正極タンク内の正極電解液の充電状態と１５％以上異なる状態であり、
    　前記第二状態は、前記電池セル内の電解液の充電状態が前記負極タンク内の負極電解液の充電状態と１５％以上異なる状態である、請求項１から請求項６のいずれか１項に記載のレドックスフロー電池システム。     The first state is a state in which the state of charge of the electrolyte in the battery cell differs from the state of charge of the positive electrode electrolyte in the positive electrode tank by 15% or more,
    7. The second state according to any one of claims 1 to 6, wherein the state of charge of the electrolyte in the battery cell differs from the state of charge of the negative electrode electrolyte in the negative electrode tank by 15% or more. The described redox flow battery system.
  8. 　前記バンクは複数設けられており、
    　前記制御器は、前記複数のバンクの各々に備わる前記電池セルの充電状態が前記複数のバンク間で順番に前記特定状態となるように前記複数のバンクの各々に備わる前記電力変換装置を制御する輪番制御器を備える、請求項１から請求項７のいずれか１項に記載のレドックスフロー電池システム。     A plurality of the banks are provided,
    The controller controls the power conversion device provided in each of the plurality of banks so that the state of charge of the battery cells provided in each of the plurality of banks sequentially becomes the specific state among the plurality of banks. 8. The redox flow battery system of any one of claims 1-7, comprising a rotatable controller.
PCT/JP2022/015672 2021-06-21 2022-03-29 Redox flow battery system WO2022270108A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006040648A (en) * 2004-07-23 2006-02-09 Kansai Electric Power Co Inc:The Operation method of redox flow battery system
JP2006147375A (en) * 2004-11-19 2006-06-08 Kansai Electric Power Co Inc:The Redox flow battery and its operation method
JP2016119258A (en) * 2014-12-22 2016-06-30 住友電気工業株式会社 Operation method for redox flow cell, and redox flow cell system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006040648A (en) * 2004-07-23 2006-02-09 Kansai Electric Power Co Inc:The Operation method of redox flow battery system
JP2006147375A (en) * 2004-11-19 2006-06-08 Kansai Electric Power Co Inc:The Redox flow battery and its operation method
JP2016119258A (en) * 2014-12-22 2016-06-30 住友電気工業株式会社 Operation method for redox flow cell, and redox flow cell system

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