WO2013046519A1 - Fuel cell system - Google Patents

Fuel cell system Download PDF

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Publication number
WO2013046519A1
WO2013046519A1 PCT/JP2012/004722 JP2012004722W WO2013046519A1 WO 2013046519 A1 WO2013046519 A1 WO 2013046519A1 JP 2012004722 W JP2012004722 W JP 2012004722W WO 2013046519 A1 WO2013046519 A1 WO 2013046519A1
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WIPO (PCT)
Prior art keywords
oxidant
fuel cell
fuel
unit
supply
Prior art date
Application number
PCT/JP2012/004722
Other languages
French (fr)
Japanese (ja)
Inventor
殉也 楠本
秋山　崇
雅樹 三井
川田　勇
Original Assignee
パナソニック株式会社
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Application filed by パナソニック株式会社 filed Critical パナソニック株式会社
Priority to DE112012000190T priority Critical patent/DE112012000190T5/en
Publication of WO2013046519A1 publication Critical patent/WO2013046519A1/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
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04186—Arrangements for control of reactant parameters, e.g. pressure or concentration of liquid-charged or electrolyte-charged reactants
    • 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
    • H01M8/24—Grouping of fuel cells, e.g. stacking of fuel cells
    • H01M8/241—Grouping of fuel cells, e.g. stacking of fuel cells with solid or matrix-supported electrolytes
    • H01M8/242—Grouping of fuel cells, e.g. stacking of fuel cells with solid or matrix-supported electrolytes comprising framed electrodes or intermediary frame-like gaskets
    • 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
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0258—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
    • H01M8/026—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant characterised by grooves, e.g. their pitch or depth
    • 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
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0258—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
    • H01M8/0263—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant having meandering or serpentine paths
    • 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
    • H01M8/04223—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
    • H01M8/04225—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells during start-up
    • 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
    • H01M8/04223—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
    • H01M8/04228—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells during shut-down
    • 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
    • H01M8/043—Processes for controlling fuel cells or fuel cell systems applied during specific periods
    • H01M8/04302—Processes for controlling fuel cells or fuel cell systems applied during specific periods applied during start-up
    • 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
    • H01M8/043—Processes for controlling fuel cells or fuel cell systems applied during specific periods
    • H01M8/04303—Processes for controlling fuel cells or fuel cell systems applied during specific periods applied during shut-down
    • 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
    • H01M8/04544—Voltage
    • 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
    • H01M8/04746—Pressure; Flow
    • H01M8/04753—Pressure; Flow of fuel cell reactants
    • 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 invention relates to a fuel cell system, and more particularly to an oxidant supply technique at the time of startup in the fuel cell system.
  • PEFC polymer electrolyte fuel cell
  • DOFC direct oxidation fuel cell
  • DMFC direct methanol fuel cell
  • a polymer electrolyte fuel cell such as a DMFC generally has a cell stack formed by stacking a plurality of unit cells.
  • Each unit cell includes a polymer electrolyte membrane, and an anode and a cathode disposed so as to sandwich the polymer electrolyte membrane therebetween.
  • Both the anode and the cathode include a catalyst layer and a diffusion layer. Methanol as a fuel is supplied to the anode, and air (oxygen) as an oxidant is supplied to the cathode.
  • Reactions occurring at the anode and cathode of the DMFC are represented by the following reaction formulas (1) and (2), respectively.
  • oxygen in the air is taken into the cathode.
  • the water produced on the cathode side is preferably recovered from the fuel cell together with the remaining oxygen without being consumed or evaporated in the cell stack during power generation.
  • some of the water generated on the cathode side tends to remain in the oxidant flow path. Due to this retention, water clogging is likely to occur in the fuel cell. When water clogging occurs, it becomes difficult to supply the oxidant substantially uniformly to the plurality of unit cells, and as a result, the power generation performance of the fuel cell decreases.
  • Patent Document 1 discloses a technique in which the amount of air supplied to the cathode at the start of power generation is larger than the amount of air supplied to the cathode during rated power generation. Specifically, the supply amount of air at the start of power generation is set to 4 to 15 times the stoichiometric ratio.
  • Patent Document 1 it is necessary to supply a large amount of air to the cathode. For this reason, it is necessary to increase the size and performance of a pump for supplying air. Therefore, an increase in power consumed by the pump, an increase in cost necessary for the pump design, and an increase in the size of the fuel cell system occur.
  • an object of the present invention is to provide a fuel cell system capable of eliminating clogging on the cathode side without causing an increase in cost or an increase in size of the system.
  • a fuel cell system controls a fuel cell, a fuel pump unit that supplies liquid fuel to the fuel cell, an oxidant pump unit that supplies oxidant to the fuel cell, and a fuel pump unit and oxidant pump unit And a voltage detector for detecting an open circuit voltage (OCV) of the fuel cell.
  • the control unit starts the supply of the liquid fuel and the oxidant to the fuel cell in the fuel pump unit and the oxidant pump unit, respectively, and then starts the supply of the oxidant from the start of the supply of the oxidant in the preparation operation at the time of starting the power generation in the fuel cell.
  • the first control is executed to stop the oxidant pump unit from supplying the oxidant to the fuel cell, and then the supply of the oxidant is stopped.
  • the second control is executed to cause the oxidant pump unit to restart the supply of the oxidant to the fuel cell.
  • water clogging on the cathode side can be eliminated without causing an increase in cost or an increase in the size of the system.
  • a fuel cell system controls a fuel cell, a fuel pump unit that supplies liquid fuel to the fuel cell, an oxidant pump unit that supplies oxidant to the fuel cell, and a fuel pump unit and oxidant pump unit And a voltage detector that detects the OCV of the fuel cell.
  • the control unit starts the supply of the liquid fuel and the oxidant to the fuel cell in the fuel pump unit and the oxidant pump unit, respectively, and then starts the supply of the oxidant from the start of the supply of the oxidant in the preparation operation at the time of starting the power generation in the fuel cell.
  • the first control is executed to stop the oxidant pump unit from supplying the oxidant to the fuel cell, and then the supply of the oxidant is stopped.
  • the second control is executed to cause the oxidant pump unit to restart the supply of the oxidant to the fuel cell.
  • control power generation preparation control executed by the control unit in the preparation operation is started as follows, for example.
  • a switch of a fuel cell or an accessory device for example, a DC / DC converter
  • the control unit detects a signal generated at this time, and the control unit starts power generation preparation control.
  • a flow path in which the flow rate of the oxidant is high and a flow path in which the flow rate of the oxidant is low are temporarily generated. And in the flow path where the flow rate of the oxidant is large, the water in the flow path is discharged by the pressure of the oxidant. Thus, water clogging on the cathode side is eliminated. Further, it is not necessary to increase the size and performance of the oxidizer pump portion, and therefore the fuel cell system does not increase the cost or increase the size of the system.
  • control unit repeatedly executes the first control and the second control until the OCV becomes a predetermined value or more. According to this specific configuration, water clogging on the cathode side is efficiently eliminated.
  • the control unit starts normal operation in the fuel cell when the OCV becomes a predetermined value or more before the first predetermined time elapses from the start of the supply of the oxidant.
  • the normal operation is started in a state where the clogging on the cathode side is eliminated. Therefore, a decrease in the power generation performance of the fuel cell is suppressed, and as a result, a target output voltage can be obtained.
  • the fuel cell includes a cell stack in which a plurality of unit cells are connected in series, and the voltage detection unit includes a voltage of the cell stack, a voltage of any one unit cell, or At least one of the voltages of the stacks of some unit cells is detected as OCV.
  • the voltage detection unit may detect the lowest voltage of the unit cell voltages as an OCV. Further, the voltage detection unit may detect a combination of these voltages as an OCV.
  • the predetermined value of OCV needs to be set according to the type of voltage detected by the voltage detector.
  • the predetermined value of OCV is preferably set to 0.75 V or more as a voltage per unit cell.
  • the determination as to whether or not the OCV is greater than or equal to a predetermined value by the control unit is executed as follows, for example.
  • the voltage detection unit outputs an arrival signal indicating this.
  • the control unit determines whether the OCV is equal to or greater than a predetermined value based on the presence / absence of the arrival signal.
  • the fuel cell is a direct oxidation fuel cell
  • the liquid fuel includes at least one fuel selected from the group consisting of methanol, ethanol, formic acid, formaldehyde, dimethyl ether, and ethylene glycol. Yes.
  • the first predetermined time is set to 10 to 300 seconds, preferably 15 to 120 seconds, more preferably 20 to 30 seconds. According to these setting ranges of the first predetermined time, the oxidant is sufficiently distributed in the cathode, and as a result, the OCV is sufficiently increased. Further, according to the set range of the first predetermined time, it is difficult for the liquid fuel crossover to cause a decrease in the cathode potential, and as a result, the decrease in the OCV is suppressed.
  • the second predetermined time is set to 1 to 180 seconds, preferably 10 to 120 seconds, more preferably 30 to 90 seconds. According to these setting ranges of the second predetermined time, the time necessary for eliminating the water clogging by the negative pressure is obtained. In addition, according to the setting range of the second predetermined time, the pump unit can be stopped for a short time, so that a large amount of power is not required for restarting, and thus a reduction in efficiency is suppressed.
  • the control unit stops the supply of the oxidant to the fuel cell to the oxidant pump unit, and supplies the liquid fuel to the fuel cell to the fuel pump unit. Stop. Further, in the second control, the control unit causes the oxidant pump unit to restart the supply of the oxidant to the fuel cell and causes the fuel pump unit to restart the supply of the liquid fuel to the fuel cell. According to this specific configuration, consumption of liquid fuel and consumption of electric power in the fuel pump unit can be suppressed, and as a result, running cost is reduced.
  • FIG. 1 is a block diagram showing an outline of a fuel cell system according to the present embodiment.
  • the fuel cell system 1 includes a DMFC 2, a fuel tank 3, a fuel pump unit 4, a recovery tank 5, and an oxidant pump unit 8.
  • the fuel tank 3 is a tank for storing liquid fuel.
  • the fuel pump unit 4 is a transport mechanism that sends the liquid fuel stored in the fuel tank 3 to the DMFC 2.
  • the recovery tank 5 is a tank that stores the discharge from the DMFC 2.
  • the oxidant pump unit 8 is a transport mechanism that introduces the oxidant into the DMFC 2.
  • Liquid fuel is a mixture of methanol and water.
  • fuel substances such as ethanol, formic acid, formaldehyde, dimethyl ether, and ethylene glycol can be used instead of or in addition to methanol.
  • concentration of methanol in the liquid fuel is set in the range of 1 to 8 mol / L, preferably in the range of 2 to 5 mol / L. These setting ranges are merely examples, and the concentration of the fuel substance in the liquid fuel can be set according to the type of fuel substance, the use state of the fuel cell, and the like.
  • air is used as the oxidizing agent.
  • compressed air, oxygen, a mixed gas containing oxygen, or the like can be used instead of air.
  • FIG. 2 is a partially cutaway view schematically showing the main part of the DMFC 2.
  • the DMFC 2 has a fuel cell case 2a and a cell stack 13 accommodated in the fuel cell case 2a.
  • the cell stack 13 is configured by stacking a plurality of unit cells so that they are connected in series.
  • the oxidant pump unit 8 and the fuel pump unit 4 may be provided either inside or outside the fuel cell case 2a.
  • FIG. 3 is an enlarged sectional view showing an outline of each unit cell constituting the cell stack 13.
  • each unit cell 20 has a polymer electrolyte membrane 22 having hydrogen ion conductivity, and an anode 24 and a cathode 26 disposed so as to sandwich the polymer electrolyte membrane 22 therebetween. is doing.
  • Methanol which is the liquid fuel 101
  • air which is the oxidant 103
  • the anode 24 includes an anode catalyst layer 28 and an anode diffusion layer 30.
  • the anode catalyst layer 28 is laminated on the polymer electrolyte membrane 22 in contact with the polymer electrolyte membrane 22.
  • the anode diffusion layer 30 includes an anode water repellent layer 32 made of a material having high water repellency and an anode porous substrate 34 subjected to a water repellent treatment.
  • the anode water repellent layer 32 and the anode porous substrate 34 are laminated in this order on the anode catalyst layer 28 (on the side opposite to the polymer electrolyte membrane 22).
  • the cathode 26 includes a cathode catalyst layer 38 and a cathode diffusion layer 40.
  • the cathode catalyst layer 38 is in contact with the surface of the polymer electrolyte membrane 22 opposite to the surface with which the anode catalyst layer 28 is in contact, on the polymer electrolyte membrane 22 (on the paper surface of FIG. It is laminated on the lower side of the electrolyte membrane 22.
  • the cathode diffusion layer 40 includes a cathode water repellent layer 42 made of a material having high water repellency and a cathode porous substrate 44 subjected to water repellency treatment. The cathode water repellent layer 42 and the cathode porous substrate 44 are laminated in this order on the cathode catalyst layer 38 (on the side opposite to the polymer electrolyte membrane 22).
  • the laminate formed by the polymer electrolyte membrane 22, the anode catalyst layer 28, and the cathode catalyst layer 38 is responsible for power generation of the fuel cell.
  • This laminate is called CCM (Catalyst Coated Membrane).
  • the anode diffusion layer 30 plays a role of uniformly dispersing the liquid fuel 101 supplied to the anode 24 and a role of smoothly discharging the carbon dioxide 102 generated at the anode 24.
  • the cathode diffusion layer 40 has a role of uniformly dispersing the oxidant 103 supplied to the cathode 26 and a role of smoothly discharging the water 104 generated at the cathode 26.
  • MEA Membrane Electrode Assembly
  • an anode side separator 36 is stacked on the anode 24, and an end plate 56 ⁇ / b> A is disposed on the anode side separator 36.
  • a cathode separator 46 is stacked on the cathode 26 (below the cathode 26 in the paper surface of FIG. 3), and further on the cathode side separator 46 (below the cathode separator 46 in the paper surface of FIG. 3).
  • End plate 56B is disposed on the side.
  • the end plates 56A and the end plates 56B are not provided in each unit cell 20, but in the stacking direction of the unit cells 20. 13 is arranged only at both ends.
  • the end plate 56A and the end plate 56B are fastened to each other in a state where the anode side separator 36 and the cathode side separator 46 are pressed against the MEA by a pressing means such as a bolt or a spring. Therefore, the contact area between the anode side separator 36 and the MEA is increased, and as a result, the electric resistance generated between the anode side separator 36 and the MEA is reduced. Further, the contact area between the cathode side separator 46 and the MEA is increased, and as a result, the electric resistance generated between the cathode side separator 46 and the MEA is reduced.
  • the anode side separator 36 has a fuel flow path 48 formed on the contact surface with the anode porous substrate 34.
  • the fuel flow path 48 is provided with an inlet for supplying the liquid fuel 101 to the anode 24 and an outlet for discharging the carbon dioxide 102 from the anode 24.
  • the fuel channel 48 is constituted by, for example, a recess or a groove that opens toward the anode porous substrate 34.
  • the cathode-side separator 46 has an oxidant channel 50 formed on the contact surface with the cathode porous substrate 44.
  • the oxidant channel 50 is provided with an inlet for supplying the oxidant 103 to the cathode 26 and an outlet for discharging the water 104 from the cathode 26.
  • the oxidant channel 50 is constituted by, for example, a recess or a groove that opens toward the cathode porous substrate 44.
  • a gasket 52 surrounding the anode 24 is provided between the polymer electrolyte membrane 22 and the anode-side separator 36. Thereby, the liquid fuel 101 supplied to the anode 24 is prevented from leaking from the unit cell 20.
  • a gasket 54 surrounding the cathode 26 is provided between the polymer electrolyte membrane 22 and the cathode side separator 46. This prevents the oxidant 103 supplied to the cathode 26 from leaking out of the unit cell 20.
  • the DMFC 2 further includes a fuel inlet 51 (see FIG. 1), a fuel outlet 14, an oxidant inlet 18 (see FIG. 2), an oxidant outlet 16, and an oxidant chamber 17 (see FIG. 2). See).
  • the oxidant inlet 18 communicates with an inlet of an oxidant flow path 50 provided in each unit cell 20.
  • the oxidant chamber 17 is provided between the oxidant inlet 18 and the oxidant pump unit 8 in the fuel cell case 2a.
  • the DMFC 2 is provided with a positive external terminal 6 and a negative external terminal 7 for outputting electricity generated by power generation.
  • liquid fuel is sent from the fuel tank 3 to the DMFC 2 and supplied from the fuel inlet 51 into the DMFC 2.
  • fuel drainage from the cell stack 13 is sent from the fuel outlet 14 to the collection tank 5 through the discharge pipe 19. Note that the fuel drainage may be sent from the fuel outlet 14 to the recovery tank 5 through a fuel discharge path different from the discharge pipe 19.
  • the oxidant pump unit 8 When the oxidant pump unit 8 is operated in the fuel cell system 1, the oxidant is supplied into the oxidant chamber 17. Thereafter, the oxidant is supplied to each unit cell 20 of the cell stack 13 through the oxidant inlet 18.
  • an oxidizing agent When an oxidizing agent is supplied to each unit cell 20 during power generation, a reaction occurs in each unit cell 20 and, as a result, water is generated. The generated water and the oxidant remaining without being consumed become a fluid and are discharged from the oxidant outlet 16. Thereafter, the fluid is sent to the collection tank 5 through the discharge pipe 109. The fluid may be sent to the recovery tank 5 through an oxidant discharge path different from the discharge pipe 109.
  • the fuel effluent, water, and oxidant are stored as the effluent from the DMFC 2.
  • this discharge contains unreacted fuel and water.
  • the exhaust from the DMFC 2 can be reused as liquid fuel.
  • the discharged material is reused as liquid fuel.
  • the recovery tank 5 has a gas-liquid separation mechanism (not shown). The gas-liquid separation mechanism separates the exhaust from the DMFC 2 into unreacted fuel and water and a gas containing an oxidant, water vapor, and the like. Thereafter, the unreacted fuel and water merge with the liquid fuel supplied from the fuel tank 3, thereby being led into the DMFC 2 together with the liquid fuel from the fuel tank 3.
  • the fuel cell system 1 further includes a DC / DC converter 9, a power storage unit 10, and a control unit 11.
  • the DC / DC converter 9 is connected to the positive external terminal 6 and the negative external terminal 7 and converts the DC voltage output from the DMFC 2 into a predetermined DC voltage.
  • the power storage unit 10 stores electricity sent from the DC / DC converter 9.
  • the control unit 11 controls the DC / DC converter 9 to adjust the direct current voltage output from the DC / DC converter 9. In addition, the control unit 11 adjusts charging / discharging in the power storage unit 10 by controlling the power storage unit 10.
  • control unit 11 controls the fuel pump unit 4 to adjust the amount of liquid fuel supplied to the DMFC 2.
  • the current output from the DMFC 2 is detected by the current sensor, and the control unit 11 causes the fuel pump unit 4 to adjust the supply amount of the liquid fuel based on the detection result of the current sensor.
  • the supply amount of the liquid fuel is adjusted in the range of 0.0138 to 0.556 cm 3 / min ⁇ cm 2 , preferably in the range of 0.0277 to 0.278 cm 3 / min ⁇ cm 2 . Note that these adjustment ranges are merely examples, and the amount of liquid fuel supplied can be adjusted according to the type of fuel material, the state of use of the fuel cell, and the like.
  • control unit 11 can stop the fuel pump unit 4 based on the switching signal generated at that time, thereby stopping the supply of fuel to the DMFC 2.
  • control unit 11 controls the oxidant pump unit 8 to adjust the supply amount of the oxidant to the DMFC 2.
  • the voltage output from the DC / DC converter 9 is detected by the voltage sensor, and the control unit 11 causes the oxidant pump unit 8 to adjust the supply amount of the oxidant based on the detection result of the voltage sensor.
  • the supply amount of the oxidizing agent is adjusted in the range of 11 to 42 cm 3 / min ⁇ cm 2 , preferably in the range of 13 to 28 cm 3 / min ⁇ cm 2 in terms of oxygen gas. These adjustment ranges are merely examples, and the supply amount of the oxidant can be adjusted according to the type of the oxidant, the use state of the fuel cell, and the like.
  • control unit 11 may include a calculation unit, a memory unit, a determination unit, and the like as necessary.
  • the control unit 11 can include, for example, a CPU (Central Processing Unit), a microcomputer, an MPU (Micro Processing Unit), a main storage device, an auxiliary storage device, and the like.
  • the fuel cell system 1 also includes a voltage detection unit 12 (see FIG. 1) and a time measurement unit (not shown).
  • the voltage detector 12 detects the OCV of the DMFC 2. Specifically, the voltage detection unit 12 uses, as OCV, at least one of the voltage of the entire cell stack 13, the voltage of any one unit cell 20, or the voltage of a stack of several unit cells 20. To detect.
  • the voltage detection unit 12 may detect the lowest voltage among the voltages of the unit cells 20 as the OCV. Further, the voltage detection unit 12 may detect a combination of these voltages as an OCV.
  • the time measuring unit measures an elapsed time from the time when the supply of the liquid fuel and the oxidant is started, and an elapsed time from the time when the supply of the liquid fuel and the oxidant is stopped.
  • the voltage detection unit 12 and the time measurement unit are included in the configuration of the control unit 11.
  • the voltage detection unit 12 and the time measurement unit may be configured separately from the control unit 11.
  • FIG. 4 is a flowchart used for power generation preparation control.
  • step S100 the fuel pump unit 4 and the oxidant pump unit 8 are controlled by the control unit 11, whereby the fuel pump unit 4 and the oxidant pump unit 8 are supplied with liquid to the DMFC 2. Start supplying fuel and oxidant, respectively.
  • the power generation preparation control is started as follows, for example.
  • the switch of the DMFC 2 or the attached device for example, the DC / DC converter 9) is switched from OFF to ON, the control unit 11 starts the power generation preparation control by detecting the signal generated at this time. .
  • step S101 the controller 11 determines whether or not the OCV of the DMFC 2 is greater than or equal to a predetermined value based on the detection result of the voltage detector 12. If it is determined in step S101 that the OCV is equal to or greater than the predetermined value (Yes determination), control proceeds to step S102, and normal operation is started in step S102. On the other hand, when it is determined in step S101 that the OCV is not equal to or greater than the predetermined value (No determination), the control proceeds to step S103.
  • the determination in step S101 is executed as follows, for example.
  • the voltage detector 12 When the OCV detected by the voltage detector 12 reaches a predetermined value, the voltage detector 12 outputs an arrival signal indicating this.
  • the control unit 11 determines whether or not the OCV of the DMFC 2 is greater than or equal to a predetermined value based on the presence / absence of the arrival signal.
  • the voltage of the whole cell stack 13 may be used for OCV used for determination of step S101, and the voltage of each unit cell 20 may be used. Further, the lowest voltage among the voltages of the unit cell 20 may be used as the OCV used for the determination in step S101. Furthermore, these voltages may be used in combination.
  • the predetermined value of OCV used for the determination in step S101 needs to be set according to the type of voltage used for the determination.
  • step S103 the control unit 11 determines whether or not the predetermined time T1 has elapsed since the supply of the liquid fuel and the oxidant in step S100 was started based on the measurement result of the time measurement unit. When it determines with predetermined time T1 not having passed in step S103 (No determination), control returns to step S101. In step S101, the controller 11 determines again whether the OCV of the DMFC 2 is equal to or greater than a predetermined value. On the other hand, when it is determined in step S103 that the predetermined time T1 has elapsed (Yes determination), the control proceeds to step S104.
  • the predetermined time T1 is 10 to 300 seconds, preferably 15 to 120 seconds, more preferably 20 to 30 seconds.
  • the predetermined time T1 is 10 to 300 seconds, preferably 15 to 120 seconds, more preferably 20 to 30 seconds.
  • the predetermined time T1 is too short, the OCV detection time is shortened. For this reason, the time required for the oxidant to sufficiently reach the inside of the electrode, that is, the time required for the OCV to sufficiently increase cannot be obtained.
  • the predetermined time T1 is too long, the OCV detection time becomes long. For this reason, methanol crossover (MCO) easily occurs. When MCO occurs, the cathode potential decreases and the OCV decreases.
  • MCO methanol crossover
  • step S104 the fuel pump unit 4 and the oxidant pump unit 8 are controlled by the control unit 11, whereby the fuel pump unit 4 and the oxidant pump unit 8 stop supplying the liquid fuel and the oxidant to the DMFC 2, respectively. . Thereafter, the control proceeds to step S105.
  • step S105 the control unit 11 determines whether or not the predetermined time T2 has elapsed since the supply of the liquid fuel and the oxidant was stopped based on the measurement result of the time measurement unit. If it is determined in step S105 that the predetermined time T2 has not elapsed (No determination), whether or not the predetermined time T2 has elapsed since the supply of liquid fuel and oxidant was stopped again in step S105. Is determined by the control unit 11. That is, if the predetermined time T2 has not elapsed, the determination in step S105 is repeated until the predetermined time T2 has elapsed. On the other hand, when it is determined in step S105 that the predetermined time T2 has elapsed (Yes determination), the control proceeds to step S100, and thereafter, the control is executed in the same manner as the flow described above.
  • the predetermined time T2 is 1 to 180 seconds, preferably 10 to 120 seconds, more preferably 30 to 90 seconds.
  • the predetermined time T2 is too short, the time from the supply of the oxidizing agent to the restart of the supply becomes short. For this reason, the time required to eliminate the water clogging due to the negative pressure cannot be obtained.
  • the predetermined time T2 is too long, the time from the supply stop of the oxidant to the restart of supply becomes long. For this reason, the stop time of a pump part becomes long, therefore electric power required for restart becomes large, As a result, efficiency falls.
  • the predetermined time T2 is not limited to the above range, and various changes can be made.
  • the power generation preparation control described above if the OCV does not exceed the predetermined value from the time when the supply of the liquid fuel and the oxidant is started until the predetermined time T1 elapses, water is clogged on the cathode side. As a result, the power generation performance of the DMFC 2 is considered to decrease. Therefore, in the power generation preparation control, the supply of the liquid fuel and the oxidant is stopped. Thereby, a negative pressure is generated in the oxidant flow path 50, and as a result, water in the oxidant flow path 50 is discharged. In the power generation preparation control, after the supply of the liquid fuel and the oxidant is stopped, the supply of the liquid fuel and the oxidant is started again.
  • the flow rate of the oxidant is not uniform in all the oxidant flow paths 50. Therefore, in the oxidant channel 50, a channel having a high oxidant flow rate and a channel having a low oxidant flow rate are temporarily generated. In the oxidant flow path 50 where the flow rate of the oxidant is large, the water in the oxidant flow path 50 is discharged by the pressure of the oxidant. Thus, water clogging on the cathode side is eliminated.
  • the supply and stop of the oxidizing agent are repeatedly executed until the OCV becomes a predetermined value or more.
  • water clogging on the cathode side is efficiently eliminated.
  • normal operation in the DMFC 2 is started when the OCV becomes a predetermined value or more. Accordingly, the normal operation is started in a state where the clogging on the cathode side is eliminated. Therefore, a decrease in the power generation performance of the DMFC 2 is suppressed, and as a result, a target output voltage can be obtained.
  • the predetermined value of OCV is preferably set to 0.75 V or more as a voltage per unit cell 20.
  • the fuel cell system 1 does not cause an increase in cost or an increase in size of the system.
  • each part structure of this invention is not restricted to the said embodiment, A various deformation
  • the supply and stop of the oxidant may be performed according to the power generation preparation control, while the liquid fuel may be maintained without stopping the supply.
  • the consumption of the liquid fuel and the power consumption in the fuel pump unit 4 can be suppressed, and as a result, the running cost is reduced. Is reduced.
  • each part structure of the fuel cell system 1 which concerns on the said embodiment is applicable not only to the fuel cell system provided with DMFC but to various fuel cell systems.
  • CCM Polymer electrolyte membrane
  • a strongly acidic ion exchange membrane having a thickness of 50 ⁇ m (trade name “Nafion (registered trademark) 112”, manufactured by DuPont) was used.
  • An anode catalyst support including anode catalyst particles and a conductive carrier supporting the particles was prepared.
  • a dispersion containing a strongly acidic ion exchange resin (trade name “Nafion (registered trademark) 5 wt% solution”, manufactured by DuPont, USA) was prepared. Then, 10 g of the anode catalyst support and 70 g of the dispersion liquid were stirred together with an appropriate amount of water by a stirrer and thereby mixed. The obtained mixture was deaerated to prepare an ink for forming an anode catalyst layer.
  • an anode catalyst layer forming ink was applied to one surface of the polymer electrolyte membrane 22 by a spray method using an air brush, thereby forming a rectangular anode catalyst layer 28 of 40 mm ⁇ 90 mm.
  • the polymer electrolyte membrane 22 was fixed by being adsorbed on a metal plate under reduced pressure.
  • the surface temperature of the metal plate was adjusted with a heater.
  • the anode catalyst layer forming ink was gradually dried during coating.
  • the dimensions of the anode catalyst layer 28 were adjusted by masking. In this example, the thickness of the anode catalyst layer 28 was 61 ⁇ m.
  • the amount of Pt—Ru contained in the anode catalyst layer 28 per unit area was 3 mg / cm 2 .
  • a cathode catalyst support including cathode catalyst particles and a conductive carrier supporting the particles was prepared.
  • the cathode catalyst particles platinum particles having an average particle diameter of 3 nm were used.
  • the carrier carbon particles having an average primary particle size of 30 nm were used. The proportion of platinum in the total weight of platinum and carbon was 80% by weight.
  • a dispersion containing a strongly acidic ion exchange resin (trade name “Nafion (registered trademark) 5 wt% solution”, manufactured by DuPont, USA) was prepared. Then, 10 g of the cathode catalyst carrier and 100 g of the dispersion liquid were stirred together with an appropriate amount of water by a stirrer, and thus mixed. The obtained mixture was degassed to produce a cathode catalyst layer forming ink.
  • the cathode catalyst layer forming ink was applied to the surface of the polymer electrolyte membrane 22 opposite to the surface on which the anode catalyst layer 28 was formed, in the same manner as the formation of the anode catalyst layer 28. Thereby, a rectangular cathode catalyst layer 38 of 40 mm ⁇ 90 mm was formed. The amount of platinum per unit area contained in the cathode catalyst layer 38 was 1 mg / cm 2 .
  • the anode catalyst layer 28 and the cathode catalyst layer 38 were arranged so that one straight line passing through the center (intersection of diagonal lines) was parallel to the thickness direction of the polymer electrolyte membrane 22.
  • Carbon cloth (trade name “AvCarb TM 1071HCB”, manufactured by Ballard Material Products) was prepared. Then, a cathode porous base material 44 having a PTFE content of 10% by weight is prepared by subjecting the carbon cloth to the same treatment as that used when the anode porous base material 34 is produced. did.
  • the water repellent layer forming ink was applied to one surface of the anode porous substrate 34 by a spray method using an air brush. As a result, a water-repellent layer forming ink coating film was formed on the surface of the anode porous substrate 34. Thereafter, the anode porous substrate 34 was placed in a thermostat set at 100 ° C., and the coating film of the water repellent layer forming ink was dried. Thereafter, the coating film of the water repellent layer forming ink was baked at 270 ° C. for 2 hours in the electric furnace together with the anode porous substrate 34. In this manner, the anode water repellent layer 32 was formed on the anode porous substrate 34, and thereby the anode diffusion layer 30 was produced.
  • a cathode water repellent layer 42 was formed on one surface of the cathode porous substrate 44 by using a method similar to the method for forming the anode water repellent layer 32, thereby producing the cathode diffusion layer 40.
  • Both the anode diffusion layer 30 and the cathode diffusion layer 40 were formed into a 40 mm ⁇ 90 mm rectangle using a punching die.
  • the anode diffusion layer 30 and the CCM were laminated so that the anode water repellent layer 32 of the anode diffusion layer 30 and the anode catalyst layer 28 of CCM were in contact with each other.
  • the cathode diffusion layer 40 and the CCM were laminated so that the cathode water-repellent layer 42 of the cathode diffusion layer 40 and the cathode catalyst layer 38 of CCM were in contact with each other.
  • the obtained laminate was pressurized at a pressure of 5 MPa for 1 minute using a hot press apparatus set at 125 ° C.
  • a hot press apparatus set at 125 ° C.
  • a sheet of ethylene propylene diene rubber (EPDM) with a thickness of 0.25 mm was prepared and cut into a 50 mm ⁇ 120 mm rectangle. Further, an opening having a size of 42 mm ⁇ 92 mm was formed in the sheet by hollowing out the central portion. In this way, two gaskets 52 and 54 were produced.
  • EPDM ethylene propylene diene rubber
  • the gaskets 52 and 54 are arranged with respect to the MEA so that the anode of the MEA is fitted into the opening of one gasket 52 and the cathode of the MEA is fitted into the opening of the other gasket 54. did.
  • a rectangular resin-impregnated graphite plate having a thickness of 1.5 mm and a size of 50 mm ⁇ 120 mm was prepared. Then, the surface of the graphite plate was cut to form a groove on the surface, thereby forming a fuel flow path 48 for supplying methanol, which is a liquid fuel, to the anode.
  • the inlet of the fuel channel 48 was formed at one short side end of the graphite plate, and the outlet of the fuel channel 48 was formed at the other short side end of the graphite plate. In this way, an anode side separator 36 was produced.
  • a resin-impregnated graphite plate having a thickness of 2 mm and a size of 50 mm ⁇ 120 mm was prepared. Then, the surface of the graphite plate was cut to form grooves on the surface, thereby forming an oxidant flow path 50 for supplying air as an oxidant to the cathode.
  • the inlet of the oxidant channel 50 was formed at one short side end of the graphite plate, and the outlet of the oxidant channel 50 was formed at the other short side end of the graphite plate. In this way, a cathode side separator 46 was produced.
  • the cross-sectional sizes of the grooves that are the fuel flow path 48 and the oxidant flow path 50 are both 1 mm wide and 0.5 mm deep. Further, in order to supply the liquid fuel and the oxidant uniformly to each part of the anode diffusion layer 30 and the cathode diffusion layer 40, the shape of the fuel channel 48 and the oxidant channel 50 is a serpentine type.
  • the anode separator 36 was laminated on the MEA anode diffusion layer 30 in a posture in which the fuel flow channel 48 was directed toward the anode diffusion layer 30.
  • the cathode separator 46 was laminated on the MEA cathode diffusion layer 40 in such a posture that the oxidant flow path 50 was directed toward the cathode diffusion layer 40. In this way, the unit cell 20 was produced.
  • the inlets of the oxidant flow paths 50 of the unit cells 20 are arranged along one side surface of the cell stack 13. Therefore, the cell stack 13 is disposed in the fuel cell case 2 a so that the side surface faces the side wall of the oxidant chamber 17.
  • a plurality of through holes serving as the oxidant inlet 18 are provided in the side wall of the oxidant chamber 17 so as to correspond to the inlet of the oxidant flow path 50, whereby the oxidant chamber 17 and the oxidant flow path 50 are mutually connected. Communicated.
  • a configuration for supplying the oxidizing agent to DMFC 2 was produced as follows.
  • a silicon tube was inserted into the oxidant inlet 18 of each unit cell 20 and these silicon tubes were joined by a branch pipe, thereby forming one flow path.
  • tip of this flow path was connected to the high pressure air cylinder which supplies compressed air.
  • a mass flow controller manufactured by Horiba, Ltd.
  • the oxidant pump unit 8 is constituted by a high-pressure air cylinder and a mass flow controller.
  • the structure for recovering the water generated in DMFC2 and the oxidant remaining without being consumed was prepared as follows. A silicon tube was inserted into the outlet of the oxidant flow path 50 of each unit cell 20, and these silicon tubes were joined by a branch pipe, thereby producing one flow path. Then, the tip of this flow path was connected to the oxidant outlet 16. Further, the oxidant outlet 16 and the recovery tank 5 were connected by another silicon tube (discharge pipe 109).
  • a configuration for supplying liquid fuel to the DMFC 2 was produced as follows. A silicon tube was inserted into the inlet of the fuel flow path 48 of each unit cell 20, and these silicon tubes were joined by a branch pipe, thereby producing one flow path. Then, the tip of this flow path was connected to the fuel pump unit 4. A precision pump (product name “Personal Pump NP-KX-100”, manufactured by Japan Precision Science Co., Ltd.) was used for the fuel pump section 4. In this embodiment, the fuel pump unit 4 is provided outside the fuel cell case 2a.
  • the configuration for recovering the fuel drainage discharged from the DMFC 2 was produced as follows. A silicon tube was inserted into the outlet of the fuel flow path 48 of each unit cell 20, and these silicon tubes were joined by a branch pipe, thereby producing one flow path. Then, the tip of this flow path was connected to the fuel outlet 14. Furthermore, the fuel outlet 14 and the collection tank 5 were connected by another silicon tube (discharge pipe 19).
  • Condition setting By controlling the fuel pump unit 4 with the control unit 11, the supply amount of the methanol aqueous solution as the liquid fuel was set to 0.083 cm 3 / min ⁇ cm 2 . Further, by controlling the mass flow controller by the control unit 11, the supply amount of air (non-humidified) as an oxidizer was set to 83.3 cm 3 / min ⁇ cm 2 .
  • An electronic load device (product name “PLZ164WA”, manufactured by Kikusui Electronics Co., Ltd.) was connected to the positive external terminal 6 and the negative external terminal 7 of the DMFC 2 via a DC / DC converter 9. Then, the current output from the DMFC 2 was adjusted so that the density of the current flowing through the electronic load device was constant at 200 mA / cm 2 . Moreover, the voltage of the cell stack 13 was used as OCV. And the predetermined value of OCV for starting a normal driving
  • FIG. 5 is a diagram illustrating a result of executing the power generation preparation control under the above-described conditions.
  • the change of OCV with respect to elapsed time is shown by the graph.
  • the power generation preparation control was started by turning on the DC / DC converter 9 and the electronic load device after 24 hours had elapsed with the power generation stopped.
  • the second supply of the liquid fuel and the oxidant was started (S100).
  • Comparative example In this comparative example, a fuel cell system having the same configuration as the above example was used. Further, the supply amounts of the liquid fuel and the oxidant and the current output from the DMFC 2 were made the same as the conditions of the above embodiment. On the other hand, the predetermined time T1 is set to infinity.
  • FIG. 6 is a diagram showing a result of executing power generation preparation control under the conditions of this comparative example.
  • the change of OCV with respect to elapsed time is shown by the graph.
  • the power generation preparation control was started by turning on the DC / DC converter 9 and the electronic load device after 24 hours had elapsed with the power generation stopped.
  • the OCV increased to 3.6V after 20 seconds, while the voltage hardly increased thereafter. Specifically, when the OCV was measured when 10 minutes and 20 seconds passed after the supply of the liquid fuel and the oxidant was started, the OCV was only 3.8V. The OCV did not reach a predetermined value.
  • the predetermined value of OCV was set to 3.6V. In this case, normal operation is started, but the output of DMFC2 is only 13 W, and the target of 20 W cannot be achieved. When power generation was further continued, the voltage in some unit cells 20 dropped to 0.2 V or less. For this reason, power generation was stopped.
  • the fuel cell system of the present invention is useful as a power source for portable small electronic devices such as notebook personal computers, mobile phones, and personal digital assistants (PDAs).
  • PDAs personal digital assistants
  • the fuel cell system of the present invention can also be applied to uses such as a power source for electric scooters.
  • Fuel cell system 2 DMFC 2a Fuel cell case 3 Fuel tank 4 Fuel pump unit 5 Collection tank 6 Positive external terminal 7 Negative external terminal 8 Oxidant pump unit 9 DC / DC converter 10 Power storage unit 11 Control unit 12 Voltage detection unit 13 Cell stack 14 Fuel outlet 16 Oxidation Oxidant outlet 17 Oxidant chamber 18 Oxidant inlet 19 Discharge pipe 20 Unit cell 22 Polymer electrolyte membrane 24 Anode 26 Cathode 36 Anode side separator 46 Cathode side separator 48 Fuel flow path 50 Oxidant flow path 51 Fuel inlet 101 Liquid fuel 102 Dioxide Carbon 103 oxidizer (air) 104 Water 109 Discharge pipe T1, T2 Predetermined time

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Abstract

Provided is a fuel cell system capable of resolving water clogging on the cathode side, without requiring an increase in cost or an enlargement of the system. During the preparatory operation of a fuel cell when starting to generate power, a control unit in a fuel cell system: causes a fuel pump unit and an oxidizing agent pump unit to respectively initiate supply of liquid fuel and an oxidizing agent to the fuel cell; then executes a first control for stopping the supply of the oxidizing agent from the oxidizing agent pump unit to the fuel cell, when the open circuit voltage does not reach or exceed a prescribed level by the time a first prescribed interval elapses since starting supply of the oxidizing agent; and then executes a second control for reinitiating supply of the oxidizing agent from the oxidizing agent pump unit to the fuel cell when a second prescribed interval elapses since stopping supply of the oxidizing agent.

Description

燃料電池システムFuel cell system
　本発明は、燃料電池システムに関し、特に燃料電池システムにおける起動時の酸化剤供給技術に関する。 The present invention relates to a fuel cell system, and more particularly to an oxidant supply technique at the time of startup in the fuel cell system.
　従来、ノート型パーソナルコンピュータ、携帯電話機、及び携帯情報端末（ＰＤＡ）などの携帯小型電子機器において、それらの電源として二次電池が用いられている。近年、これらの携帯小型電子機器において、二次電池の代わりに燃料電池を用いることが検討されている。燃料電池は、燃料の補充により連続的に発電することが可能である。従って、二次電池は充電が必要であるのに対し、燃料電池は充電が不要である。よって、携帯小型電子機器の電源として燃料電池を用いることは、携帯小型電子機器の利便性が向上することを期待させる。 Conventionally, in portable small electronic devices such as notebook personal computers, mobile phones, and personal digital assistants (PDAs), secondary batteries have been used as power sources thereof. In recent years, it has been studied to use a fuel cell instead of a secondary battery in these portable small electronic devices. The fuel cell can continuously generate power by replenishing fuel. Therefore, the secondary battery needs to be charged, whereas the fuel cell does not need to be charged. Therefore, using a fuel cell as a power source for a portable small electronic device is expected to improve the convenience of the portable small electronic device.
　燃料電池には、使用される電解質の種類によって分類される種々のタイプが存在する。特に高分子電解質型燃料電池（ＰＥＦＣ）は、作動温度が低く、且つ出力密度が高い。このため、車載用電源や家庭用コージェネレーションシステム用電源などの大型電源において、ＰＥＦＣが実用化されつつある。これに加えて、ＰＥＦＣは、携帯小型電子機器用の電源としても有望視されている。 There are various types of fuel cells classified according to the type of electrolyte used. In particular, a polymer electrolyte fuel cell (PEFC) has a low operating temperature and a high output density. For this reason, PEFC is being put to practical use in large power sources such as in-vehicle power sources and household cogeneration system power sources. In addition to this, PEFC is also considered promising as a power source for portable small electronic devices.
　ＰＥＦＣのうち直接酸化型燃料電池（ＤＯＦＣ）は、常温で液体燃料を直接的に酸化させることにより電気エネルギーを発生させている。そして、ＤＯＦＣでは、液体燃料を水素に改質する必要がない。よって、ＰＥＦＣのなかでも特にＤＯＦＣは、改質器を備える必要がなく、従って小型化が容易である。又、ＤＯＦＣのなかでも、燃料としてメタノールを用いる直接メタノール型燃料電池（ＤＭＦＣ）は、エネルギー効率及び発電出力が他のＤＯＦＣより優れている。従って、ＤＭＦＣは、携帯小型電子機器用の電源として最も有望視されている。 The direct oxidation fuel cell (DOFC) among PEFCs generates electric energy by directly oxidizing liquid fuel at room temperature. And in DOFC, it is not necessary to reform liquid fuel into hydrogen. Therefore, DOFC in particular among PEFCs does not need to be provided with a reformer, and thus can be easily downsized. Among DOFCs, a direct methanol fuel cell (DMFC) using methanol as a fuel is superior in energy efficiency and power generation output to other DOFCs. Therefore, DMFC is regarded as the most promising power source for portable small electronic devices.
　ＤＭＦＣなどの高分子電解質型燃料電池は、一般的に、複数の単位セルを積層することにより構成されたセルスタックを有している。各単位セルは、高分子電解質膜と、該高分子電解質膜を間に挟む様に配されたアノード及びカソードとを含んでいる。アノード及びカソードは何れも、触媒層及び拡散層を含んでいる。アノードには、燃料であるメタノールが供給され、カソードには、酸化剤である空気（酸素）が供給される。 A polymer electrolyte fuel cell such as a DMFC generally has a cell stack formed by stacking a plurality of unit cells. Each unit cell includes a polymer electrolyte membrane, and an anode and a cathode disposed so as to sandwich the polymer electrolyte membrane therebetween. Both the anode and the cathode include a catalyst layer and a diffusion layer. Methanol as a fuel is supplied to the anode, and air (oxygen) as an oxidant is supplied to the cathode.
　ＤＭＦＣのアノード及びカソードにて生じる反応は、下記反応式（１）及び（２）によってそれぞれ表される。尚、一般的に、カソードには、空気中の酸素が取り込まれる。
　アノード：  ＣＨ3ＯＨ＋Ｈ2Ｏ　→　ＣＯ2＋６Ｈ+＋６ｅ- （１）
　カソード：  （３／２）Ｏ2＋６Ｈ+＋６ｅ-　→　３Ｈ2Ｏ  （２） Reactions occurring at the anode and cathode of the DMFC are represented by the following reaction formulas (1) and (2), respectively. In general, oxygen in the air is taken into the cathode.
Anode: CH 3 OH + H 2 O → CO 2 + 6H + + 6e − (1)
Cathode: (3/2) O 2 + 6H + + 6e − → 3H 2 O (2)
　カソード側で生じた水は、発電中にセルスタック内で蒸発するか、若しくは消費されずに残った酸素と共に燃料電池から回収されることが好ましい。しかし、カソード側で生じた水は、その一部が酸化剤の流路内に滞留したままになり易い。そして、この滞留が原因となって、燃料電池内には水詰まりが発生し易い。水詰まりが発生した場合、複数の単位セルに対して酸化剤を略均一に供給することが困難となり、その結果、燃料電池の発電性能が低下することになる。 The water produced on the cathode side is preferably recovered from the fuel cell together with the remaining oxygen without being consumed or evaporated in the cell stack during power generation. However, some of the water generated on the cathode side tends to remain in the oxidant flow path. Due to this retention, water clogging is likely to occur in the fuel cell. When water clogging occurs, it becomes difficult to supply the oxidant substantially uniformly to the plurality of unit cells, and as a result, the power generation performance of the fuel cell decreases.
　そこで、上述した様なカソード側の水詰まりを改善する方法が検討されている。例えば、特許文献１には、発電開始時にカソードに供給する空気量を、定格発電時にカソードに供給する空気量より大きくする技術が開示されている。具体的には、発電開始時の空気の供給量が、化学両論比に対して４～１５倍の量に設定されている。 Therefore, a method for improving the water clogging on the cathode side as described above has been studied. For example, Patent Document 1 discloses a technique in which the amount of air supplied to the cathode at the start of power generation is larger than the amount of air supplied to the cathode during rated power generation. Specifically, the supply amount of air at the start of power generation is set to 4 to 15 times the stoichiometric ratio.
特開２００６－２７８２６４号公報JP 2006-278264 A
　しかしながら、特許文献１に開示の技術では、カソードに対して多量の空気を供給する必要がある。このため、空気を供給するためのポンプの大型化や高性能化が必要である。よって、ポンプにて消費される電力の増加や、ポンプの設計に必要なコストの増大、更には燃料電池システムの大型化が生じることになる。 However, in the technique disclosed in Patent Document 1, it is necessary to supply a large amount of air to the cathode. For this reason, it is necessary to increase the size and performance of a pump for supplying air. Therefore, an increase in power consumed by the pump, an increase in cost necessary for the pump design, and an increase in the size of the fuel cell system occur.
　そこで、本発明の目的は、カソード側の水詰まりを解消することが可能な燃料電池システムを、コストの増大やシステムの大型化を招かずに提供することである。 Therefore, an object of the present invention is to provide a fuel cell system capable of eliminating clogging on the cathode side without causing an increase in cost or an increase in size of the system.
　本発明に係る燃料電池システムは、燃料電池と、燃料電池に液体燃料を供給する燃料ポンプ部と、燃料電池に酸化剤を供給する酸化剤ポンプ部と、燃料ポンプ部及び酸化剤ポンプ部を制御する制御部と、燃料電池の開回路電圧（ＯＣＶ）を検出する電圧検出部とを備えている。制御部は、燃料電池での発電起動時の準備運転において、燃料電池への液体燃料及び酸化剤の供給をそれぞれ燃料ポンプ部及び酸化剤ポンプ部に開始させた後、酸化剤の供給開始から第１の所定時間が経過する迄にＯＣＶが所定値以上とならなかった場合、燃料電池への酸化剤の供給を酸化剤ポンプ部に停止させる第１制御を実行し、その後、酸化剤の供給停止から第２の所定時間が経過したときに、燃料電池への酸化剤の供給を酸化剤ポンプ部に再び開始させる第２制御を実行する。 A fuel cell system according to the present invention controls a fuel cell, a fuel pump unit that supplies liquid fuel to the fuel cell, an oxidant pump unit that supplies oxidant to the fuel cell, and a fuel pump unit and oxidant pump unit And a voltage detector for detecting an open circuit voltage (OCV) of the fuel cell. The control unit starts the supply of the liquid fuel and the oxidant to the fuel cell in the fuel pump unit and the oxidant pump unit, respectively, and then starts the supply of the oxidant from the start of the supply of the oxidant in the preparation operation at the time of starting the power generation in the fuel cell. If the OCV does not become a predetermined value or more before the predetermined time of 1 elapses, the first control is executed to stop the oxidant pump unit from supplying the oxidant to the fuel cell, and then the supply of the oxidant is stopped. When the second predetermined time has elapsed, the second control is executed to cause the oxidant pump unit to restart the supply of the oxidant to the fuel cell.
　本発明に係る燃料電池システムによれば、コストの増大やシステムの大型化を招かずに、カソード側の水詰まりを解消することができる。 According to the fuel cell system of the present invention, water clogging on the cathode side can be eliminated without causing an increase in cost or an increase in the size of the system.
　本発明の新規な特徴を添付の特許請求の範囲に記述するが、本発明は、構成及び内容の両方に関し、本発明の他の目的及び特徴と併せ、図面を照合した以下の詳細な説明により更によく理解されるであろう。 The novel features of the invention are set forth in the appended claims, and the invention will be described both in terms of structure and content, together with other objects and features of the invention, and by the following detailed description in conjunction with the drawings. It will be better understood.
本発明の一実施形態に係る燃料電池システムの概略を示したブロック図である。It is the block diagram which showed the outline of the fuel cell system which concerns on one Embodiment of this invention. 燃料電池システムが備える燃料電池の要部を模式的に示した一部切欠き図である。It is the partially cutaway figure which showed typically the principal part of the fuel cell with which a fuel cell system is provided. 燃料電池に含まれる単位セルの概略を示した拡大断面図である。It is the expanded sectional view which showed the outline of the unit cell contained in a fuel cell. 燃料電池システムに使用される発電準備制御のフローチャートである。It is a flowchart of the electric power generation preparation control used for a fuel cell system. 実施例において発電準備制御を実行した結果を、経過時間とＯＣＶとの関係により示した図である。It is the figure which showed the result of having performed power generation preparation control in the Example by the relationship between elapsed time and OCV. 比較例において発電準備制御を実行した結果を、経過時間とＯＣＶとの関係により示した図である。It is the figure which showed the result of having performed power generation preparation control in the comparative example by the relationship between elapsed time and OCV.
　本発明に係る燃料電池システムは、燃料電池と、燃料電池に液体燃料を供給する燃料ポンプ部と、燃料電池に酸化剤を供給する酸化剤ポンプ部と、燃料ポンプ部及び酸化剤ポンプ部を制御する制御部と、燃料電池のＯＣＶを検出する電圧検出部とを備えている。制御部は、燃料電池での発電起動時の準備運転において、燃料電池への液体燃料及び酸化剤の供給をそれぞれ燃料ポンプ部及び酸化剤ポンプ部に開始させた後、酸化剤の供給開始から第１の所定時間が経過する迄にＯＣＶが所定値以上とならなかった場合、燃料電池への酸化剤の供給を酸化剤ポンプ部に停止させる第１制御を実行し、その後、酸化剤の供給停止から第２の所定時間が経過したときに、燃料電池への酸化剤の供給を酸化剤ポンプ部に再び開始させる第２制御を実行する。 A fuel cell system according to the present invention controls a fuel cell, a fuel pump unit that supplies liquid fuel to the fuel cell, an oxidant pump unit that supplies oxidant to the fuel cell, and a fuel pump unit and oxidant pump unit And a voltage detector that detects the OCV of the fuel cell. The control unit starts the supply of the liquid fuel and the oxidant to the fuel cell in the fuel pump unit and the oxidant pump unit, respectively, and then starts the supply of the oxidant from the start of the supply of the oxidant in the preparation operation at the time of starting the power generation in the fuel cell. If the OCV does not become a predetermined value or more before the predetermined time of 1 elapses, the first control is executed to stop the oxidant pump unit from supplying the oxidant to the fuel cell, and then the supply of the oxidant is stopped. When the second predetermined time has elapsed, the second control is executed to cause the oxidant pump unit to restart the supply of the oxidant to the fuel cell.
　ここで、準備運転にて制御部が実行する上記制御（発電準備制御）は、例えば次の様に開始される。燃料電池又は付属装置（例えばＤＣ／ＤＣコンバータ等）のスイッチがオフからオンに切り替えられたとき、このときに発生する信号を制御部が検知することにより、制御部が発電準備制御を開始する。 Here, the control (power generation preparation control) executed by the control unit in the preparation operation is started as follows, for example. When a switch of a fuel cell or an accessory device (for example, a DC / DC converter) is switched from OFF to ON, the control unit detects a signal generated at this time, and the control unit starts power generation preparation control.
　上記燃料電池システムにおいて、酸化剤の供給開始から第１の所定時間が経過する迄にＯＣＶが所定値以上とならなかった場合、カソード側に水詰まりが発生しており、これにより燃料電池の発電性能が低下すると考えられる。そこで、上記燃料電池システムでは、酸化剤の供給を停止させる。これにより、酸化剤の流路内に負圧が発生し、その結果、流路内の水が排出される。又、上記燃料電池システムでは、酸化剤の供給の停止後、酸化剤の供給を再び開始する。ここで、酸化剤の供給を開始した直後においては、酸化剤の流速は全ての流路において均一にならない。従って、酸化剤の流路には、一時的に、酸化剤の流速が大きい流路と、酸化剤の流速が小さい流路とが生じることになる。そして、酸化剤の流速が大きい流路では、該流路内の水が酸化剤の圧力によって排出される。斯くして、カソード側の水詰まりが解消される。又、酸化剤ポンプ部の大型化や高性能化が必要でなく、従って上記燃料電池システムは、コストの増大やシステムの大型化を招かない。 In the above fuel cell system, when the OCV does not become a predetermined value or more before the first predetermined time elapses from the start of the supply of the oxidant, water clogging occurs on the cathode side. It is considered that the performance is reduced. Therefore, in the fuel cell system, the supply of the oxidant is stopped. As a result, a negative pressure is generated in the oxidant flow path, and as a result, water in the flow path is discharged. In the fuel cell system, after the supply of the oxidant is stopped, the supply of the oxidant is started again. Here, immediately after the supply of the oxidizing agent is started, the flow rate of the oxidizing agent is not uniform in all the flow paths. Therefore, in the oxidant flow path, a flow path in which the flow rate of the oxidant is high and a flow path in which the flow rate of the oxidant is low are temporarily generated. And in the flow path where the flow rate of the oxidant is large, the water in the flow path is discharged by the pressure of the oxidant. Thus, water clogging on the cathode side is eliminated. Further, it is not necessary to increase the size and performance of the oxidizer pump portion, and therefore the fuel cell system does not increase the cost or increase the size of the system.
　上記燃料電池システムの具体的構成において、制御部は、ＯＣＶが所定値以上になる迄、第１制御と第２制御とを繰り返し実行する。この具体的構成によれば、カソード側の水詰まりが効率良く解消されることになる。 In the specific configuration of the fuel cell system, the control unit repeatedly executes the first control and the second control until the OCV becomes a predetermined value or more. According to this specific configuration, water clogging on the cathode side is efficiently eliminated.
　上記燃料電池システムにおいて、制御部は、酸化剤の供給開始から第１の所定時間が経過する迄にＯＣＶが所定値以上になった場合、燃料電池での通常運転を開始する。これにより、カソード側の水詰まりが解消された状態で通常運転が開始されることになる。よって、燃料電池の発電性能の低下が抑制され、その結果、目標の出力電圧を得ることができる。 In the fuel cell system, the control unit starts normal operation in the fuel cell when the OCV becomes a predetermined value or more before the first predetermined time elapses from the start of the supply of the oxidant. As a result, the normal operation is started in a state where the clogging on the cathode side is eliminated. Therefore, a decrease in the power generation performance of the fuel cell is suppressed, and as a result, a target output voltage can be obtained.
　上記燃料電池システムの具体的構成において、燃料電池は、複数の単位セルが直列に接続されたセルスタックを有し、電圧検出部は、セルスタックの電圧、何れか１つの単位セルの電圧、又は幾つかの単位セルの積層体の電圧の少なくとも何れか１つを、ＯＣＶとして検出する。又、電圧検出部は、単位セルの電圧のうち最低の電圧を、ＯＣＶとして検出してもよい。更に、電圧検出部は、これらの電圧を組み合わせたものをＯＣＶとして検出してもよい。但し、ＯＣＶの所定値は、電圧検出部が検出する電圧の種類に応じて設定する必要がある。尚、ＯＣＶの所定値は、１つの単位セルあたりの電圧で０．７５Ｖ以上に設定することが好ましい。 In the specific configuration of the fuel cell system, the fuel cell includes a cell stack in which a plurality of unit cells are connected in series, and the voltage detection unit includes a voltage of the cell stack, a voltage of any one unit cell, or At least one of the voltages of the stacks of some unit cells is detected as OCV. The voltage detection unit may detect the lowest voltage of the unit cell voltages as an OCV. Further, the voltage detection unit may detect a combination of these voltages as an OCV. However, the predetermined value of OCV needs to be set according to the type of voltage detected by the voltage detector. The predetermined value of OCV is preferably set to 0.75 V or more as a voltage per unit cell.
　制御部によるＯＣＶが所定値以上であるか否かの判定は、例えば次の様に実行される。電圧検出部には、該電圧検出部が検出するＯＣＶが所定値に到達したとき、これを表す到達信号を出力させる。制御部は、この到達信号の有無に基づいて、ＯＣＶが所定値以上であるか否かを判定する。 The determination as to whether or not the OCV is greater than or equal to a predetermined value by the control unit is executed as follows, for example. When the OCV detected by the voltage detection unit reaches a predetermined value, the voltage detection unit outputs an arrival signal indicating this. The control unit determines whether the OCV is equal to or greater than a predetermined value based on the presence / absence of the arrival signal.
　上記燃料電池システムにおいて、燃料電池は、直接酸化型燃料電池であり、液体燃料は、メタノール、エタノール、蟻酸、ホルムアルデヒド、ジメチルエーテル、及びエチレングリコールよりなる群から選択される少なくとも１種類の燃料を含んでいる。 In the fuel cell system, the fuel cell is a direct oxidation fuel cell, and the liquid fuel includes at least one fuel selected from the group consisting of methanol, ethanol, formic acid, formaldehyde, dimethyl ether, and ethylene glycol. Yes.
　上記燃料電池システムにおいて、第１の所定時間は、１０～３００秒、好ましくは１５～１２０秒、より好ましくは２０～３０秒に設定される。第１の所定時間のこれらの設定範囲によれば、酸化剤がカソード内に十分に行き渡り、その結果、ＯＣＶが十分に上昇することになる。又、第１の所定時間の上記設定範囲によれば、カソード電位の低下を招き得る液体燃料のクロスオーバが発生し難く、その結果、ＯＣＶの低下が抑制される。 In the fuel cell system, the first predetermined time is set to 10 to 300 seconds, preferably 15 to 120 seconds, more preferably 20 to 30 seconds. According to these setting ranges of the first predetermined time, the oxidant is sufficiently distributed in the cathode, and as a result, the OCV is sufficiently increased. Further, according to the set range of the first predetermined time, it is difficult for the liquid fuel crossover to cause a decrease in the cathode potential, and as a result, the decrease in the OCV is suppressed.
　又、上記燃料電池システムにおいて、第２の所定時間は、１～１８０秒、好ましくは１０～１２０秒、より好ましくは３０～９０秒に設定される。第２の所定時間のこれらの設定範囲によれば、負圧によって水詰まりを解消するために必要な時間が得られる。又、第２の所定時間の上記設定範囲によれば、ポンプ部の停止時間が短くて済むので、再起動に大きな電力が必要でなく、従って効率の低下が抑制される。 In the fuel cell system, the second predetermined time is set to 1 to 180 seconds, preferably 10 to 120 seconds, more preferably 30 to 90 seconds. According to these setting ranges of the second predetermined time, the time necessary for eliminating the water clogging by the negative pressure is obtained. In addition, according to the setting range of the second predetermined time, the pump unit can be stopped for a short time, so that a large amount of power is not required for restarting, and thus a reduction in efficiency is suppressed.
　上記燃料電池システムの具体的構成において、制御部は、第１制御において、燃料電池への酸化剤の供給を酸化剤ポンプ部に停止させると共に、燃料電池への液体燃料の供給を燃料ポンプ部に停止させる。制御部は更に、第２制御において、燃料電池への酸化剤の供給を酸化剤ポンプ部に再び開始させると共に、燃料電池への液体燃料の供給を燃料ポンプ部に再び開始させる。この具体的構成によれば、液体燃料の消費や燃料ポンプ部での電力の消費を抑制することができ、その結果、ランニングコストが低減される。 In the specific configuration of the fuel cell system, in the first control, the control unit stops the supply of the oxidant to the fuel cell to the oxidant pump unit, and supplies the liquid fuel to the fuel cell to the fuel pump unit. Stop. Further, in the second control, the control unit causes the oxidant pump unit to restart the supply of the oxidant to the fuel cell and causes the fuel pump unit to restart the supply of the liquid fuel to the fuel cell. According to this specific configuration, consumption of liquid fuel and consumption of electric power in the fuel pump unit can be suppressed, and as a result, running cost is reduced.
　以下、直接メタノール型燃料電池（ＤＭＦＣ）を備えた燃料電池システムに本発明を実施した形態について、図面に沿って具体的に説明する。 Hereinafter, an embodiment in which the present invention is implemented in a fuel cell system including a direct methanol fuel cell (DMFC) will be described in detail with reference to the drawings.
　図１は、本実施形態に係る燃料電池システムの概略を示したブロック図である。図１に示す様に、燃料電池システム１は、ＤＭＦＣ２、燃料タンク３、燃料ポンプ部４、回収タンク５、及び酸化剤ポンプ部８を備えている。ここで、燃料タンク３は、液体燃料を貯留するタンクである。燃料ポンプ部４は、燃料タンク３に貯留されている液体燃料をＤＭＦＣ２へ送る輸送機構である。回収タンク５は、ＤＭＦＣ２からの排出物を収容するタンクである。酸化剤ポンプ部８は、酸化剤をＤＭＦＣ２内へ導入する輸送機構である。 FIG. 1 is a block diagram showing an outline of a fuel cell system according to the present embodiment. As shown in FIG. 1, the fuel cell system 1 includes a DMFC 2, a fuel tank 3, a fuel pump unit 4, a recovery tank 5, and an oxidant pump unit 8. Here, the fuel tank 3 is a tank for storing liquid fuel. The fuel pump unit 4 is a transport mechanism that sends the liquid fuel stored in the fuel tank 3 to the DMFC 2. The recovery tank 5 is a tank that stores the discharge from the DMFC 2. The oxidant pump unit 8 is a transport mechanism that introduces the oxidant into the DMFC 2.
　液体燃料は、メタノールと水との混合物である。尚、液体燃料には、メタノールに代えて又はこれに加えて、エタノール、蟻酸、ホルムアルデヒド、ジメチルエーテル、及びエチレングリコールなどの燃料物質を用いることができる。又、液体燃料中のメタノールの濃度は、１～８ｍｏｌ／Ｌの範囲、好ましくは２～５ｍｏｌ／Ｌの範囲に設定される。尚、これらの設定範囲は一例であり、燃料物質の種類や燃料電池の使用状況等に応じて、液体燃料中の燃料物質の濃度を設定することができる。一方、酸化剤には、空気が用いられる。尚、酸化剤には、空気に変えて、圧縮空気、酸素、酸素を含む混合ガスなどを用いることができる。 Liquid fuel is a mixture of methanol and water. For the liquid fuel, fuel substances such as ethanol, formic acid, formaldehyde, dimethyl ether, and ethylene glycol can be used instead of or in addition to methanol. The concentration of methanol in the liquid fuel is set in the range of 1 to 8 mol / L, preferably in the range of 2 to 5 mol / L. These setting ranges are merely examples, and the concentration of the fuel substance in the liquid fuel can be set according to the type of fuel substance, the use state of the fuel cell, and the like. On the other hand, air is used as the oxidizing agent. As the oxidant, compressed air, oxygen, a mixed gas containing oxygen, or the like can be used instead of air.
　図２は、ＤＭＦＣ２の要部を模式的に示した一部切欠き図である。図２に示す様に、ＤＭＦＣ２は、燃料電池ケース２ａと、該燃料電池ケース２ａ内に収納されたセルスタック１３とを有している。セルスタック１３は、複数の単位セルを、これらが直列に接続される様に積層することにより構成されている。尚、酸化剤ポンプ部８及び燃料ポンプ部４は、燃料電池ケース２ａの内外の何れに設けられていてもよい。 FIG. 2 is a partially cutaway view schematically showing the main part of the DMFC 2. As shown in FIG. 2, the DMFC 2 has a fuel cell case 2a and a cell stack 13 accommodated in the fuel cell case 2a. The cell stack 13 is configured by stacking a plurality of unit cells so that they are connected in series. The oxidant pump unit 8 and the fuel pump unit 4 may be provided either inside or outside the fuel cell case 2a.
　図３は、セルスタック１３を構成する各単位セルの概略を示した拡大断面図である。図３に示す様に、各単位セル２０は、水素イオン伝導性を有した高分子電解質膜２２と、該高分子電解質膜２２を間に挟む様に配されたアノード２４及びカソード２６とを有している。アノード２４には、液体燃料１０１であるメタノールが供給され、カソード２６には、酸化剤１０３である空気が供給される。 FIG. 3 is an enlarged sectional view showing an outline of each unit cell constituting the cell stack 13. As shown in FIG. 3, each unit cell 20 has a polymer electrolyte membrane 22 having hydrogen ion conductivity, and an anode 24 and a cathode 26 disposed so as to sandwich the polymer electrolyte membrane 22 therebetween. is doing. Methanol, which is the liquid fuel 101, is supplied to the anode 24, and air, which is the oxidant 103, is supplied to the cathode 26.
　アノード２４は、アノード触媒層２８及びアノード拡散層３０を含んでいる。アノード触媒層２８は、高分子電解質膜２２に接した状態で該高分子電解質膜２２上に積層されている。アノード拡散層３０は、撥水性の高い材料からなるアノード撥水層３２と、撥水処理が施されたアノード多孔質基材３４とを含んでいる。アノード撥水層３２及びアノード多孔質基材３４は、この順序で、アノード触媒層２８上（高分子電解質膜２２とは反対側）に積層されている。 The anode 24 includes an anode catalyst layer 28 and an anode diffusion layer 30. The anode catalyst layer 28 is laminated on the polymer electrolyte membrane 22 in contact with the polymer electrolyte membrane 22. The anode diffusion layer 30 includes an anode water repellent layer 32 made of a material having high water repellency and an anode porous substrate 34 subjected to a water repellent treatment. The anode water repellent layer 32 and the anode porous substrate 34 are laminated in this order on the anode catalyst layer 28 (on the side opposite to the polymer electrolyte membrane 22).
　カソード２６は、カソード触媒層３８及びカソード拡散層４０を含んでいる。カソード触媒層３８は、高分子電解質膜２２の表面のうちアノード触媒層２８が接した面とは反対側の面に接した状態で、該高分子電解質膜２２上（図３の紙面において高分子電解質膜２２の下側）に積層されている。カソード拡散層４０は、撥水性の高い材料からなるカソード撥水層４２と、撥水処理が施されたカソード多孔質基材４４とを含んでいる。カソード撥水層４２及びカソード多孔質基材４４は、この順序で、カソード触媒層３８上（高分子電解質膜２２とは反対側）に積層されている。 The cathode 26 includes a cathode catalyst layer 38 and a cathode diffusion layer 40. The cathode catalyst layer 38 is in contact with the surface of the polymer electrolyte membrane 22 opposite to the surface with which the anode catalyst layer 28 is in contact, on the polymer electrolyte membrane 22 (on the paper surface of FIG. It is laminated on the lower side of the electrolyte membrane 22. The cathode diffusion layer 40 includes a cathode water repellent layer 42 made of a material having high water repellency and a cathode porous substrate 44 subjected to water repellency treatment. The cathode water repellent layer 42 and the cathode porous substrate 44 are laminated in this order on the cathode catalyst layer 38 (on the side opposite to the polymer electrolyte membrane 22).
　高分子電解質膜２２、アノード触媒層２８、及びカソード触媒層３８によって形成される積層体は、燃料電池の発電を担っている。尚、この積層体は、ＣＣＭ（Catalyst Coated Membrane）と呼ばれている。又、アノード拡散層３０は、アノード２４に供給される液体燃料１０１を均一に分散する役割と、アノード２４にて生成される二酸化炭素１０２を円滑に排出する役割とを担っている。更に、カソード拡散層４０は、カソード２６に供給される酸化剤１０３を均一に分散する役割と、カソード２６にて生成される水１０４を円滑に排出する役割とを担っている。尚、ＣＣＭ、アノード拡散層３０、及びカソード拡散層４０によって形成される積層体は、ＭＥＡ（Membrane Electrode Assembly）と呼ばれている。 The laminate formed by the polymer electrolyte membrane 22, the anode catalyst layer 28, and the cathode catalyst layer 38 is responsible for power generation of the fuel cell. This laminate is called CCM (Catalyst Coated Membrane). The anode diffusion layer 30 plays a role of uniformly dispersing the liquid fuel 101 supplied to the anode 24 and a role of smoothly discharging the carbon dioxide 102 generated at the anode 24. Further, the cathode diffusion layer 40 has a role of uniformly dispersing the oxidant 103 supplied to the cathode 26 and a role of smoothly discharging the water 104 generated at the cathode 26. The laminate formed by the CCM, the anode diffusion layer 30 and the cathode diffusion layer 40 is called MEA (Membrane Electrode Assembly).
　アノード２４、高分子電解質膜２２、及びカソード２６の積層方向において、アノード２４上にはアノード側セパレータ３６が積層され、更にアノード側セパレータ３６上には端板５６Ａが配置されている。又、上記積層方向において、カソード２６上（図３の紙面においてカソード２６の下側）にはカソード側セパレータ４６が積層され、更にカソード側セパレータ４６上（図３の紙面においてカソード側セパレータ４６の下側）には端板５６Ｂが配置されている。尚、セルスタック１３が複数の単位セル２０から構成される本実施形態においては、端板５６Ａ及び端板５６Ｂは、各単位セル２０に設けられるのではなく、単位セル２０の積層方向においてセルスタック１３の両端にのみ配置される。 In the stacking direction of the anode 24, the polymer electrolyte membrane 22, and the cathode 26, an anode side separator 36 is stacked on the anode 24, and an end plate 56 </ b> A is disposed on the anode side separator 36. In the stacking direction, a cathode separator 46 is stacked on the cathode 26 (below the cathode 26 in the paper surface of FIG. 3), and further on the cathode side separator 46 (below the cathode separator 46 in the paper surface of FIG. 3). End plate 56B is disposed on the side. In the present embodiment in which the cell stack 13 includes a plurality of unit cells 20, the end plates 56A and the end plates 56B are not provided in each unit cell 20, but in the stacking direction of the unit cells 20. 13 is arranged only at both ends.
　端板５６Ａ及び端板５６Ｂは、ボルトやバネ等の加圧手段により、アノード側セパレータ３６及びカソード側セパレータ４６をＭＥＡへ押し付けた状態で、互いに締結されている。従って、アノード側セパレータ３６とＭＥＡとの接触面積が増大し、その結果、アノード側セパレータ３６とＭＥＡとの間に生じる電気抵抗が小さくなっている。又、カソード側セパレータ４６とＭＥＡとの接触面積が増大し、その結果、カソード側セパレータ４６とＭＥＡとの間に生じる電気抵抗が小さくなっている。 The end plate 56A and the end plate 56B are fastened to each other in a state where the anode side separator 36 and the cathode side separator 46 are pressed against the MEA by a pressing means such as a bolt or a spring. Therefore, the contact area between the anode side separator 36 and the MEA is increased, and as a result, the electric resistance generated between the anode side separator 36 and the MEA is reduced. Further, the contact area between the cathode side separator 46 and the MEA is increased, and as a result, the electric resistance generated between the cathode side separator 46 and the MEA is reduced.
　アノード側セパレータ３６は、アノード多孔質基材３４との接触面に形成された燃料流路４８を有している。燃料流路４８には、アノード２４に液体燃料１０１を供給するための入口と、アノード２４から二酸化炭素１０２を排出するための出口とが設けられている。燃料流路４８は、例えば、アノード多孔質基材３４に向かって開口した凹部や溝によって構成される。 The anode side separator 36 has a fuel flow path 48 formed on the contact surface with the anode porous substrate 34. The fuel flow path 48 is provided with an inlet for supplying the liquid fuel 101 to the anode 24 and an outlet for discharging the carbon dioxide 102 from the anode 24. The fuel channel 48 is constituted by, for example, a recess or a groove that opens toward the anode porous substrate 34.
　カソード側セパレータ４６は、カソード多孔質基材４４との接触面に形成された酸化剤流路５０を有している。酸化剤流路５０には、カソード２６に酸化剤１０３を供給するための入口と、カソード２６から水１０４を排出するための出口とが設けられている。酸化剤流路５０は、例えば、カソード多孔質基材４４に向かって開口する凹部や溝によって構成される。 The cathode-side separator 46 has an oxidant channel 50 formed on the contact surface with the cathode porous substrate 44. The oxidant channel 50 is provided with an inlet for supplying the oxidant 103 to the cathode 26 and an outlet for discharging the water 104 from the cathode 26. The oxidant channel 50 is constituted by, for example, a recess or a groove that opens toward the cathode porous substrate 44.
　高分子電解質膜２２とアノード側セパレータ３６との間には、アノード２４を包囲するガスケット５２が設けられている。これにより、アノード２４に供給された液体燃料１０１が単位セル２０から漏れ出すことを防止している。又、高分子電解質膜２２とカソード側セパレータ４６との間には、カソード２６を包囲するガスケット５４が設けられている。これにより、カソード２６に供給された酸化剤１０３が単位セル２０から漏れ出すことを防止している。 Between the polymer electrolyte membrane 22 and the anode-side separator 36, a gasket 52 surrounding the anode 24 is provided. Thereby, the liquid fuel 101 supplied to the anode 24 is prevented from leaking from the unit cell 20. A gasket 54 surrounding the cathode 26 is provided between the polymer electrolyte membrane 22 and the cathode side separator 46. This prevents the oxidant 103 supplied to the cathode 26 from leaking out of the unit cell 20.
　図１及び図２に示す様に、ＤＭＦＣ２は更に、燃料入口５１（図１参照）、燃料出口１４、酸化剤入口１８（図２参照）、酸化剤出口１６、及び酸化剤チャンバ１７（図２参照）を有している。酸化剤入口１８は、各単位セル２０に設けられた酸化剤流路５０の入口に通じている。酸化剤チャンバ１７は、燃料電池ケース２ａ内にて酸化剤入口１８と酸化剤ポンプ部８との間に設けられている。又、図１に示す様に、ＤＭＦＣ２には、発電によって生じた電気を出力する正極外部端子６及び負極外部端子７が設けられている。 As shown in FIGS. 1 and 2, the DMFC 2 further includes a fuel inlet 51 (see FIG. 1), a fuel outlet 14, an oxidant inlet 18 (see FIG. 2), an oxidant outlet 16, and an oxidant chamber 17 (see FIG. 2). See). The oxidant inlet 18 communicates with an inlet of an oxidant flow path 50 provided in each unit cell 20. The oxidant chamber 17 is provided between the oxidant inlet 18 and the oxidant pump unit 8 in the fuel cell case 2a. As shown in FIG. 1, the DMFC 2 is provided with a positive external terminal 6 and a negative external terminal 7 for outputting electricity generated by power generation.
　燃料電池システム１において燃料ポンプ部４を動作させた場合、液体燃料が、燃料タンク３からＤＭＦＣ２へ送られ、燃料入口５１からＤＭＦＣ２内へ供給される。一方、セルスタック１３からの燃料排液は、排出管１９を通じて燃料出口１４から回収タンク５へ送られる。尚、燃料排液は、排出管１９とは別の燃料排出路を通って燃料出口１４から回収タンク５へ送られてもよい。 When the fuel pump unit 4 is operated in the fuel cell system 1, liquid fuel is sent from the fuel tank 3 to the DMFC 2 and supplied from the fuel inlet 51 into the DMFC 2. On the other hand, fuel drainage from the cell stack 13 is sent from the fuel outlet 14 to the collection tank 5 through the discharge pipe 19. Note that the fuel drainage may be sent from the fuel outlet 14 to the recovery tank 5 through a fuel discharge path different from the discharge pipe 19.
　燃料電池システム１において酸化剤ポンプ部８を動作させた場合、酸化剤が、酸化剤チャンバ１７内に供給される。その後、酸化剤は、酸化剤入口１８を通じてセルスタック１３の各単位セル２０に供給される。発電中に各単位セル２０に対して酸化剤が供給されると、各単位セル２０では反応が起こり、その結果、水が生成されることになる。そして、生成された水と、消費されずに残った酸化剤とが、流体となって酸化剤出口１６から排出される。その後、流体は、排出管１０９を通じて回収タンク５へ送られる。尚、流体は、排出管１０９とは別の酸化剤排出路を通って回収タンク５へ送られてもよい。 When the oxidant pump unit 8 is operated in the fuel cell system 1, the oxidant is supplied into the oxidant chamber 17. Thereafter, the oxidant is supplied to each unit cell 20 of the cell stack 13 through the oxidant inlet 18. When an oxidizing agent is supplied to each unit cell 20 during power generation, a reaction occurs in each unit cell 20 and, as a result, water is generated. The generated water and the oxidant remaining without being consumed become a fluid and are discharged from the oxidant outlet 16. Thereafter, the fluid is sent to the collection tank 5 through the discharge pipe 109. The fluid may be sent to the recovery tank 5 through an oxidant discharge path different from the discharge pipe 109.
　回収タンク５には、上述の如く燃料排液、水、及び酸化剤が、ＤＭＦＣ２からの排出物として貯留することになる。尚、この排出物には、未反応の燃料と水とが含まれている。従って、ＤＭＦＣ２からの排出物は、液体燃料として再利用することが可能である。本実施形態においては、図１に示す様に排出物を液体燃料として再利用している。具体的には、回収タンク５は、気液分離機構（図示せず）を有している。そして、該気液分離機構により、ＤＭＦＣ２からの排出物が、未反応の燃料及び水と、酸化剤や水蒸気などを含むガスとに分離される。その後、未反応の燃料及び水は、燃料タンク３から供給される液体燃料に合流し、これにより、燃料タンク３からの液体燃料と共にＤＭＦＣ２内へ導かれる。 In the recovery tank 5, as described above, the fuel effluent, water, and oxidant are stored as the effluent from the DMFC 2. Note that this discharge contains unreacted fuel and water. Accordingly, the exhaust from the DMFC 2 can be reused as liquid fuel. In the present embodiment, as shown in FIG. 1, the discharged material is reused as liquid fuel. Specifically, the recovery tank 5 has a gas-liquid separation mechanism (not shown). The gas-liquid separation mechanism separates the exhaust from the DMFC 2 into unreacted fuel and water and a gas containing an oxidant, water vapor, and the like. Thereafter, the unreacted fuel and water merge with the liquid fuel supplied from the fuel tank 3, thereby being led into the DMFC 2 together with the liquid fuel from the fuel tank 3.
　図１に示す様に、燃料電池システム１は更に、ＤＣ／ＤＣコンバータ９、蓄電部１０、及び制御部１１を備えている。ＤＣ／ＤＣコンバータ９は、正極外部端子６及び負極外部端子７に接続されており、ＤＭＦＣ２から出力される直流電圧を所定の直流電圧に変換する。蓄電部１０は、ＤＣ／ＤＣコンバータ９から送られる電気を蓄積する。制御部１１は、ＤＣ／ＤＣコンバータ９を制御することにより、ＤＣ／ＤＣコンバータ９から出力する直流電圧を調整する。又、制御部１１は、蓄電部１０を制御することにより、蓄電部１０での充放電を調整する。 As shown in FIG. 1, the fuel cell system 1 further includes a DC / DC converter 9, a power storage unit 10, and a control unit 11. The DC / DC converter 9 is connected to the positive external terminal 6 and the negative external terminal 7 and converts the DC voltage output from the DMFC 2 into a predetermined DC voltage. The power storage unit 10 stores electricity sent from the DC / DC converter 9. The control unit 11 controls the DC / DC converter 9 to adjust the direct current voltage output from the DC / DC converter 9. In addition, the control unit 11 adjusts charging / discharging in the power storage unit 10 by controlling the power storage unit 10.
　更に、制御部１１は、燃料ポンプ部４を制御することにより、ＤＭＦＣ２への液体燃料の供給量を調整する。例えば、ＤＭＦＣ２から出力される電流が電流センサによって検出され、制御部１１は、電流センサの検出結果に基づいて燃料ポンプ部４に液体燃料の供給量を調整させる。液体燃料の供給量は、０．０１３８～０．５５６ｃｍ3／ｍｉｎ・ｃｍ2の範囲、好ましくは０．０２７７～０．２７８ｃｍ3／ｍｉｎ・ｃｍ2の範囲に調整される。尚、これらの調整範囲は一例であり、燃料物質の種類や燃料電池の使用状況等に応じて、液体燃料の供給量を調整することができる。 Further, the control unit 11 controls the fuel pump unit 4 to adjust the amount of liquid fuel supplied to the DMFC 2. For example, the current output from the DMFC 2 is detected by the current sensor, and the control unit 11 causes the fuel pump unit 4 to adjust the supply amount of the liquid fuel based on the detection result of the current sensor. The supply amount of the liquid fuel is adjusted in the range of 0.0138 to 0.556 cm 3 / min · cm 2 , preferably in the range of 0.0277 to 0.278 cm 3 / min · cm 2 . Note that these adjustment ranges are merely examples, and the amount of liquid fuel supplied can be adjusted according to the type of fuel material, the state of use of the fuel cell, and the like.
　又、ＤＭＦＣ２を発電状態から停止状態へ切り替えた場合、そのときに発生する切替え信号に基づいて制御部１１は燃料ポンプ部４を停止させ、これによりＤＭＦＣ２への燃料の供給を止めることができる。 In addition, when the DMFC 2 is switched from the power generation state to the stop state, the control unit 11 can stop the fuel pump unit 4 based on the switching signal generated at that time, thereby stopping the supply of fuel to the DMFC 2.
　更に、制御部１１は、酸化剤ポンプ部８を制御することにより、ＤＭＦＣ２への酸化剤の供給量を調整する。例えば、ＤＣ／ＤＣコンバータ９から出力される電圧が電圧センサによって検出され、制御部１１は、電圧センサの検出結果に基づいて酸化剤ポンプ部８に酸化剤の供給量を調整させる。酸化剤の供給量は、酸素ガス換算で、１１～４２ｃｍ3／ｍｉｎ・ｃｍ2の範囲、好ましくは１３～２８ｃｍ3／ｍｉｎ・ｃｍ2の範囲に調整される。尚、これらの調整範囲は一例であり、酸化剤の種類や燃料電池の使用状況等に応じて、酸化剤の供給量を調整することができる。 Further, the control unit 11 controls the oxidant pump unit 8 to adjust the supply amount of the oxidant to the DMFC 2. For example, the voltage output from the DC / DC converter 9 is detected by the voltage sensor, and the control unit 11 causes the oxidant pump unit 8 to adjust the supply amount of the oxidant based on the detection result of the voltage sensor. The supply amount of the oxidizing agent is adjusted in the range of 11 to 42 cm 3 / min · cm 2 , preferably in the range of 13 to 28 cm 3 / min · cm 2 in terms of oxygen gas. These adjustment ranges are merely examples, and the supply amount of the oxidant can be adjusted according to the type of the oxidant, the use state of the fuel cell, and the like.
　尚、制御部１１には、必要に応じて、演算部、メモリ部、判定部などが含まれていてもよい。制御部１１には、例えば、ＣＰＵ（Central Processing Unit：中央処理装置）、マイクロコンピュータ、ＭＰＵ（Micro Processing Unit：マイクロプロセッサ）、主記憶装置、補助記憶装置などを含めることができる。 Note that the control unit 11 may include a calculation unit, a memory unit, a determination unit, and the like as necessary. The control unit 11 can include, for example, a CPU (Central Processing Unit), a microcomputer, an MPU (Micro Processing Unit), a main storage device, an auxiliary storage device, and the like.
　燃料電池システム１は、電圧検出部１２（図１参照）及び時間計測部（図示せず）も備えている。電圧検出部１２は、ＤＭＦＣ２のＯＣＶを検出する。具体的には、電圧検出部１２は、ＯＣＶとして、セルスタック１３全体の電圧、何れか１つの単位セル２０の電圧、又は幾つかの単位セル２０の積層体の電圧の少なくとも何れか１つを検出する。又、電圧検出部１２は、単位セル２０の電圧のうち最低の電圧を、ＯＣＶとして検出してもよい。更に、電圧検出部１２は、これらの電圧を組み合わせたものをＯＣＶとして検出してもよい。時間計測部は、液体燃料及び酸化剤の供給が開始された時点からの経過時間、及び液体燃料及び酸化剤の供給が停止された時点からの経過時間を計測する。本実施形態においては、電圧検出部１２及び時間計測部は、制御部１１の構成に含まれている。尚、電圧検出部１２及び時間計測部は、制御部１１とは別に構成されていてもよい。 The fuel cell system 1 also includes a voltage detection unit 12 (see FIG. 1) and a time measurement unit (not shown). The voltage detector 12 detects the OCV of the DMFC 2. Specifically, the voltage detection unit 12 uses, as OCV, at least one of the voltage of the entire cell stack 13, the voltage of any one unit cell 20, or the voltage of a stack of several unit cells 20. To detect. The voltage detection unit 12 may detect the lowest voltage among the voltages of the unit cells 20 as the OCV. Further, the voltage detection unit 12 may detect a combination of these voltages as an OCV. The time measuring unit measures an elapsed time from the time when the supply of the liquid fuel and the oxidant is started, and an elapsed time from the time when the supply of the liquid fuel and the oxidant is stopped. In the present embodiment, the voltage detection unit 12 and the time measurement unit are included in the configuration of the control unit 11. The voltage detection unit 12 and the time measurement unit may be configured separately from the control unit 11.
　次に、上記燃料電池システム１において発電起動時の準備運転にて制御部１１が実行する制御（以下、「発電準備制御」と称す。）について説明する。図４は、発電準備制御に使用されるフローチャートである。 Next, the control (hereinafter referred to as “power generation preparation control”) executed by the control unit 11 in the preparation operation at the time of starting power generation in the fuel cell system 1 will be described. FIG. 4 is a flowchart used for power generation preparation control.
　発電準備制御が開始されると、先ずステップＳ１００において、燃料ポンプ部４及び酸化剤ポンプ部８が制御部１１によって制御され、これにより燃料ポンプ部４及び酸化剤ポンプ部８は、ＤＭＦＣ２への液体燃料及び酸化剤の供給をそれぞれ開始する。尚、発電準備制御は、例えば次の様に開始される。ＤＭＦＣ２又は付属装置（例えばＤＣ／ＤＣコンバータ９）のスイッチがオフからオンに切り替えられたとき、このときに発生する信号を制御部１１が検知することにより、制御部１１が発電準備制御を開始する。 When the power generation preparation control is started, first, in step S100, the fuel pump unit 4 and the oxidant pump unit 8 are controlled by the control unit 11, whereby the fuel pump unit 4 and the oxidant pump unit 8 are supplied with liquid to the DMFC 2. Start supplying fuel and oxidant, respectively. The power generation preparation control is started as follows, for example. When the switch of the DMFC 2 or the attached device (for example, the DC / DC converter 9) is switched from OFF to ON, the control unit 11 starts the power generation preparation control by detecting the signal generated at this time. .
　次にステップＳ１０１において、ＤＭＦＣ２のＯＣＶが所定値以上であるか否かが、電圧検出部１２の検出結果に基づいて制御部１１によって判定される。ステップＳ１０１にてＯＣＶが所定値以上であると判定された場合（Ｙｅｓ判定）、制御はステップＳ１０２へ移行し、ステップＳ１０２において通常運転が開始される。一方、ステップＳ１０１にてＯＣＶが所定値以上でないと判定された場合（Ｎｏ判定）、制御はステップＳ１０３へ移行する。 Next, in step S101, the controller 11 determines whether or not the OCV of the DMFC 2 is greater than or equal to a predetermined value based on the detection result of the voltage detector 12. If it is determined in step S101 that the OCV is equal to or greater than the predetermined value (Yes determination), control proceeds to step S102, and normal operation is started in step S102. On the other hand, when it is determined in step S101 that the OCV is not equal to or greater than the predetermined value (No determination), the control proceeds to step S103.
　ステップＳ１０１での判定は、例えば次の様に実行される。電圧検出部１２には、該電圧検出部１２が検出するＯＣＶが所定値に到達したとき、これを表す到達信号を出力させる。制御部１１は、この到達信号の有無に基づいて、ＤＭＦＣ２のＯＣＶが所定値以上であるか否かを判定する。尚、ステップＳ１０１の判定に用いるＯＣＶには、セルスタック１３全体の電圧を用いてもよいし、各単位セル２０の電圧を用いてもよい。又、ステップＳ１０１の判定に用いるＯＣＶとして、単位セル２０の電圧のうち最低の電圧を用いてもよい。更には、これらの電圧を組み合わせて用いてもよい。但し、ステップＳ１０１の判定に用いるＯＣＶの所定値は、該判定に用いる電圧の種類に応じて設定する必要がある。 The determination in step S101 is executed as follows, for example. When the OCV detected by the voltage detector 12 reaches a predetermined value, the voltage detector 12 outputs an arrival signal indicating this. The control unit 11 determines whether or not the OCV of the DMFC 2 is greater than or equal to a predetermined value based on the presence / absence of the arrival signal. In addition, the voltage of the whole cell stack 13 may be used for OCV used for determination of step S101, and the voltage of each unit cell 20 may be used. Further, the lowest voltage among the voltages of the unit cell 20 may be used as the OCV used for the determination in step S101. Furthermore, these voltages may be used in combination. However, the predetermined value of OCV used for the determination in step S101 needs to be set according to the type of voltage used for the determination.
　ステップＳ１０３では、ステップＳ１００での液体燃料及び酸化剤の供給が開始された時点から所定時間Ｔ１が経過したか否かが、時間計測部の計測結果に基づいて制御部１１によって判定される。ステップＳ１０３にて所定時間Ｔ１が経過していないと判定された場合（Ｎｏ判定）、制御はステップＳ１０１に戻る。そして、ステップＳ１０１にて再度、ＤＭＦＣ２のＯＣＶが所定値以上であるか否かが、制御部１１によって判定される。一方、ステップＳ１０３にて所定時間Ｔ１が経過したと判定された場合（Ｙｅｓ判定）、制御はステップＳ１０４へ移行する。 In step S103, the control unit 11 determines whether or not the predetermined time T1 has elapsed since the supply of the liquid fuel and the oxidant in step S100 was started based on the measurement result of the time measurement unit. When it determines with predetermined time T1 not having passed in step S103 (No determination), control returns to step S101. In step S101, the controller 11 determines again whether the OCV of the DMFC 2 is equal to or greater than a predetermined value. On the other hand, when it is determined in step S103 that the predetermined time T1 has elapsed (Yes determination), the control proceeds to step S104.
　所定時間Ｔ１は、１０～３００秒、好ましくは１５～１２０秒、より好ましくは２０～３０秒である。ここで、所定時間Ｔ１が短すぎると、ＯＣＶの検出時間が短くなる。このため、酸化剤が電極内に十分に行き渡るのに必要な時間、即ちＯＣＶが十分に上昇するのに必要な時間が、得られなくなる。一方、所定時間Ｔ１が長すぎると、ＯＣＶの検出時間が長くなる。このため、メタノールクロスオーバ（ＭＣＯ）が発生し易くなる。ＭＣＯが発生すると、カソード電位が低下してＯＣＶが低下する。尚、所定時間Ｔ１は、上記範囲に限定されるものではなく、種々の変更が可能である。 The predetermined time T1 is 10 to 300 seconds, preferably 15 to 120 seconds, more preferably 20 to 30 seconds. Here, if the predetermined time T1 is too short, the OCV detection time is shortened. For this reason, the time required for the oxidant to sufficiently reach the inside of the electrode, that is, the time required for the OCV to sufficiently increase cannot be obtained. On the other hand, if the predetermined time T1 is too long, the OCV detection time becomes long. For this reason, methanol crossover (MCO) easily occurs. When MCO occurs, the cathode potential decreases and the OCV decreases. The predetermined time T1 is not limited to the above range, and various changes can be made.
　ステップＳ１０４では、燃料ポンプ部４及び酸化剤ポンプ部８が制御部１１によって制御され、これにより燃料ポンプ部４及び酸化剤ポンプ部８は、ＤＭＦＣ２への液体燃料及び酸化剤の供給をそれぞれ停止する。その後、制御はステップＳ１０５へ移行する。 In step S104, the fuel pump unit 4 and the oxidant pump unit 8 are controlled by the control unit 11, whereby the fuel pump unit 4 and the oxidant pump unit 8 stop supplying the liquid fuel and the oxidant to the DMFC 2, respectively. . Thereafter, the control proceeds to step S105.
　ステップＳ１０５では、液体燃料及び酸化剤の供給が停止された時点から所定時間Ｔ２が経過したか否かが、時間計測部の計測結果に基づいて制御部１１によって判定される。ステップＳ１０５にて所定時間Ｔ２が経過していないと判定された場合（Ｎｏ判定）、ステップＳ１０５にて再度、液体燃料及び酸化剤の供給が停止された時点から所定時間Ｔ２が経過したか否かが、制御部１１によって判定される。即ち、所定時間Ｔ２が経過していなければ、所定時間Ｔ２が経過する迄、ステップＳ１０５の判定が繰り返される。一方、ステップＳ１０５にて所定時間Ｔ２が経過したと判定された場合（Ｙｅｓ判定）、制御はステップＳ１００に移行し、以降、上述した流れと同様に制御が実行される。 In step S105, the control unit 11 determines whether or not the predetermined time T2 has elapsed since the supply of the liquid fuel and the oxidant was stopped based on the measurement result of the time measurement unit. If it is determined in step S105 that the predetermined time T2 has not elapsed (No determination), whether or not the predetermined time T2 has elapsed since the supply of liquid fuel and oxidant was stopped again in step S105. Is determined by the control unit 11. That is, if the predetermined time T2 has not elapsed, the determination in step S105 is repeated until the predetermined time T2 has elapsed. On the other hand, when it is determined in step S105 that the predetermined time T2 has elapsed (Yes determination), the control proceeds to step S100, and thereafter, the control is executed in the same manner as the flow described above.
　所定時間Ｔ２は、１～１８０秒、好ましくは１０～１２０秒、より好ましくは３０～９０秒である。ここで、所定時間Ｔ２が短すぎると、酸化剤の供給停止から供給再開までの時間が短くなる。このため、負圧によって水詰まりを解消するために必要な時間が得られなくなる。一方、所定時間Ｔ２が長すぎると、酸化剤の供給停止から供給再開までの時間が長くなる。このため、ポンプ部の停止時間が長くなり、従って再起動に必要な電力が大きくなり、その結果、効率が低下することになる。尚、所定時間Ｔ２は、上記範囲に限定されるものではなく、種々の変更が可能である。 The predetermined time T2 is 1 to 180 seconds, preferably 10 to 120 seconds, more preferably 30 to 90 seconds. Here, if the predetermined time T2 is too short, the time from the supply of the oxidizing agent to the restart of the supply becomes short. For this reason, the time required to eliminate the water clogging due to the negative pressure cannot be obtained. On the other hand, if the predetermined time T2 is too long, the time from the supply stop of the oxidant to the restart of supply becomes long. For this reason, the stop time of a pump part becomes long, therefore electric power required for restart becomes large, As a result, efficiency falls. The predetermined time T2 is not limited to the above range, and various changes can be made.
　上記発電準備制御において、液体燃料及び酸化剤の供給が開始された時点から所定時間Ｔ１が経過する迄の間にＯＣＶが所定値以上とならなかった場合、カソード側に水詰まりが発生しており、これによりＤＭＦＣ２の発電性能が低下すると考えられる。そこで、上記発電準備制御では、液体燃料及び酸化剤の供給を停止させる。これにより、酸化剤流路５０内に負圧が発生し、その結果、酸化剤流路５０内の水が排出される。又、上記発電準備制御では、液体燃料及び酸化剤の供給の停止後、液体燃料及び酸化剤の供給を再び開始する。ここで、酸化剤の供給を開始した直後においては、酸化剤の流速は全ての酸化剤流路５０において均一にならない。従って、酸化剤流路５０には、一時的に、酸化剤の流速が大きい流路と、酸化剤の流速が小さい流路とが生じることになる。そして、酸化剤の流速が大きい酸化剤流路５０では、該酸化剤流路５０内の水が酸化剤の圧力によって排出される。斯くして、カソード側の水詰まりが解消される。 In the power generation preparation control described above, if the OCV does not exceed the predetermined value from the time when the supply of the liquid fuel and the oxidant is started until the predetermined time T1 elapses, water is clogged on the cathode side. As a result, the power generation performance of the DMFC 2 is considered to decrease. Therefore, in the power generation preparation control, the supply of the liquid fuel and the oxidant is stopped. Thereby, a negative pressure is generated in the oxidant flow path 50, and as a result, water in the oxidant flow path 50 is discharged. In the power generation preparation control, after the supply of the liquid fuel and the oxidant is stopped, the supply of the liquid fuel and the oxidant is started again. Here, immediately after the supply of the oxidant is started, the flow rate of the oxidant is not uniform in all the oxidant flow paths 50. Therefore, in the oxidant channel 50, a channel having a high oxidant flow rate and a channel having a low oxidant flow rate are temporarily generated. In the oxidant flow path 50 where the flow rate of the oxidant is large, the water in the oxidant flow path 50 is discharged by the pressure of the oxidant. Thus, water clogging on the cathode side is eliminated.
　更に、上記発電準備制御では、ＯＣＶが所定値以上になる迄、酸化剤の供給と停止とが繰り返し実行される。これにより、カソード側の水詰まりが効率良く解消されることになる。又、上記発電準備制御によれば、ＯＣＶが所定値以上になった場合にＤＭＦＣ２での通常運転が開始される。従って、カソード側の水詰まりが解消された状態で通常運転が開始されることになる。よって、ＤＭＦＣ２の発電性能の低下が抑制され、その結果、目標の出力電圧を得ることができる。尚、ＯＣＶの所定値は、１つの単位セル２０あたりの電圧で０．７５Ｖ以上に設定することが好ましい。 Furthermore, in the power generation preparation control, the supply and stop of the oxidizing agent are repeatedly executed until the OCV becomes a predetermined value or more. As a result, water clogging on the cathode side is efficiently eliminated. Further, according to the power generation preparation control, normal operation in the DMFC 2 is started when the OCV becomes a predetermined value or more. Accordingly, the normal operation is started in a state where the clogging on the cathode side is eliminated. Therefore, a decrease in the power generation performance of the DMFC 2 is suppressed, and as a result, a target output voltage can be obtained. The predetermined value of OCV is preferably set to 0.75 V or more as a voltage per unit cell 20.
　上記発電準備制御によれば、酸化剤ポンプ部８の大型化や高性能化を必要とせずにカソード側の水詰まりを解消することができる。従って、上記燃料電池システム１は、コストの増大やシステムの大型化を招かない。 According to the power generation preparation control described above, water clogging on the cathode side can be eliminated without requiring an increase in size and performance of the oxidant pump unit 8. Therefore, the fuel cell system 1 does not cause an increase in cost or an increase in size of the system.
　尚、本発明の各部構成は、上記実施形態に限らず、特許請求の範囲に記載の技術的範囲内で種々の変形が可能である。例えば、上記実施形態において、発電準備制御に従って酸化剤の供給及び停止を実行する一方、液体燃料については供給を停止せずにそのまま維持してもよい。但し、上記実施形態の如く酸化剤の供給の停止と共に液体燃料の供給も停止することにより、液体燃料の消費や燃料ポンプ部４での電力の消費を抑制することができ、その結果、ランニングコストが低減される。 In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. For example, in the above embodiment, the supply and stop of the oxidant may be performed according to the power generation preparation control, while the liquid fuel may be maintained without stopping the supply. However, by stopping the supply of the oxidant and the supply of the liquid fuel as in the above embodiment, the consumption of the liquid fuel and the power consumption in the fuel pump unit 4 can be suppressed, and as a result, the running cost is reduced. Is reduced.
　又、上記実施形態に係る燃料電池システム１の各部構成は、ＤＭＦＣを備えた燃料電池システムに限らず、種々の燃料電池システムに適用することができる。 Moreover, each part structure of the fuel cell system 1 which concerns on the said embodiment is applicable not only to the fuel cell system provided with DMFC but to various fuel cell systems.
　以下、本発明の実施例について具体的に説明する。尚、以下に説明する実施例は、本発明を何ら限定するものではない。 Hereinafter, examples of the present invention will be described in detail. In addition, the Example described below does not limit this invention at all.
　１．ＣＣＭの作製
（高分子電解質膜）
　高分子電解質膜２２として、厚さ５０μｍの強酸性イオン交換膜（商品名「Ｎａｆｉｏｎ（登録商標）１１２」、デュポン社製）を使用した。 1. Production of CCM (Polymer electrolyte membrane)
As the polymer electrolyte membrane 22, a strongly acidic ion exchange membrane having a thickness of 50 μm (trade name “Nafion (registered trademark) 112”, manufactured by DuPont) was used.
（アノード触媒層の形成）
　アノード触媒粒子と、これを担持する導電性の担体とを含むアノード触媒担持体を調製した。アノード触媒粒子としては、平均粒径５ｎｍの白金－ルテニウム合金微粒子（Ｐｔ：Ｒｕの原子比＝１：１）を用いた。担体としては、平均一次粒子径３０ｎｍのカーボン粒子を用いた。白金－ルテニウム合金とカーボンとの合計重量に占める白金－ルテニウム合金の割合は、８０重量％とした。 (Formation of anode catalyst layer)
An anode catalyst support including anode catalyst particles and a conductive carrier supporting the particles was prepared. As anode catalyst particles, platinum-ruthenium alloy fine particles (Pt: Ru atomic ratio = 1: 1) having an average particle diameter of 5 nm were used. As the carrier, carbon particles having an average primary particle diameter of 30 nm were used. The ratio of the platinum-ruthenium alloy to the total weight of the platinum-ruthenium alloy and carbon was 80% by weight.
　次に、強酸性イオン交換樹脂を含有する分散液（商品名「Ｎａｆｉｏｎ（登録商標）５重量％溶液」、米国デュポン社製）を用意した。そして、１０ｇのアノード触媒担持体と７０ｇの分散液とを、適量の水と共に攪拌機によって攪拌し、これにより混合させた。得られた混合物を脱気して、アノード触媒層形成用インクを作製した。 Next, a dispersion containing a strongly acidic ion exchange resin (trade name “Nafion (registered trademark) 5 wt% solution”, manufactured by DuPont, USA) was prepared. Then, 10 g of the anode catalyst support and 70 g of the dispersion liquid were stirred together with an appropriate amount of water by a stirrer and thereby mixed. The obtained mixture was deaerated to prepare an ink for forming an anode catalyst layer.
　その後、エアーブラシを使用したスプレー法により、高分子電解質膜２２の一方の表面にアノード触媒層形成用インクを塗布し、これにより４０ｍｍ×９０ｍｍの長方形のアノード触媒層２８を形成した。このとき、高分子電解質膜２２は、減圧により金属板に吸着させて固定した。又、金属板の表面温度を、ヒータにより調整した。更に、アノード触媒層形成用インクを、塗布中に漸次乾燥させた。アノード触媒層２８の寸法は、マスキングにより調整した。本実施例では、アノード触媒層２８の厚みを６１μｍとした。又、アノード触媒層２８に含まれる単位面積あたりのＰｔ－Ｒｕの量は、３ｍｇ／ｃｍ2であった。 Thereafter, an anode catalyst layer forming ink was applied to one surface of the polymer electrolyte membrane 22 by a spray method using an air brush, thereby forming a rectangular anode catalyst layer 28 of 40 mm × 90 mm. At this time, the polymer electrolyte membrane 22 was fixed by being adsorbed on a metal plate under reduced pressure. The surface temperature of the metal plate was adjusted with a heater. Further, the anode catalyst layer forming ink was gradually dried during coating. The dimensions of the anode catalyst layer 28 were adjusted by masking. In this example, the thickness of the anode catalyst layer 28 was 61 μm. The amount of Pt—Ru contained in the anode catalyst layer 28 per unit area was 3 mg / cm 2 .
（カソード触媒層の形成）
　カソード触媒粒子と、これを担持する導電性の担体とを含むカソード触媒担持体を調製した。カソード触媒粒子としては、平均粒径３ｎｍの白金粒子を用いた。担体としては、平均一次粒子径が３０ｎｍのカーボン粒子を用いた。白金とカーボンとの合計重量に占める白金の割合は、８０重量％とした。 (Formation of cathode catalyst layer)
A cathode catalyst support including cathode catalyst particles and a conductive carrier supporting the particles was prepared. As the cathode catalyst particles, platinum particles having an average particle diameter of 3 nm were used. As the carrier, carbon particles having an average primary particle size of 30 nm were used. The proportion of platinum in the total weight of platinum and carbon was 80% by weight.
　次に、強酸性イオン交換樹脂を含有する分散液（商品名「Ｎａｆｉｏｎ（登録商標）５重量％溶液」、米国デュポン社製）を用意した。そして、１０ｇのカソード触媒担持体と１００ｇの分散液とを、適量の水と共に攪拌機によって攪拌し、これにより混合させた。得られた混合物を脱気して、カソード触媒層形成用インクを作製した。 Next, a dispersion containing a strongly acidic ion exchange resin (trade name “Nafion (registered trademark) 5 wt% solution”, manufactured by DuPont, USA) was prepared. Then, 10 g of the cathode catalyst carrier and 100 g of the dispersion liquid were stirred together with an appropriate amount of water by a stirrer, and thus mixed. The obtained mixture was degassed to produce a cathode catalyst layer forming ink.
　その後、カソード触媒層形成用インクを、アノード触媒層２８の形成と同様の方法で、高分子電解質膜２２の表面のうちアノード触媒層２８が形成された面とは反対側の面に塗布した。これにより、４０ｍｍ×９０ｍｍの長方形のカソード触媒層３８を形成した。カソード触媒層３８に含まれる単位面積あたりの白金の量は、１ｍｇ／ｃｍ2であった。尚、アノード触媒層２８とカソード触媒層３８とは、それぞれの中心（対角線の交点）を通る１つの直線が高分子電解質膜２２の厚さ方向と平行になる様に、配置した。 Thereafter, the cathode catalyst layer forming ink was applied to the surface of the polymer electrolyte membrane 22 opposite to the surface on which the anode catalyst layer 28 was formed, in the same manner as the formation of the anode catalyst layer 28. Thereby, a rectangular cathode catalyst layer 38 of 40 mm × 90 mm was formed. The amount of platinum per unit area contained in the cathode catalyst layer 38 was 1 mg / cm 2 . The anode catalyst layer 28 and the cathode catalyst layer 38 were arranged so that one straight line passing through the center (intersection of diagonal lines) was parallel to the thickness direction of the polymer electrolyte membrane 22.
　２．ＭＥＡの作製
（アノード多孔質基材の作製）
　撥水処理が施されたカーボンペーパ（商品名「ＴＧＰ－Ｈ－０９０」、厚さ約３００μｍ、東レ（株）製）を用意した。そして、該カーボンペーパを、希釈されたＰＴＦＥ（ポリテトラフルオロエチレン）のディスパージョン（商品名「Ｄ－１」、ダイキン工業（株）製）に１分間、浸漬させた。次いで、そのカーボンペーパを、１００℃に温度設定された熱風乾燥機中で乾燥させた。乾燥後のカーボンペーパを、電気炉によって２７０℃で２時間、焼成した。この様にして、ＰＴＦＥの含有量が１０重量％であるアノード多孔質基材３４を作製した。 2. Production of MEA (production of anode porous substrate)
Carbon paper (trade name “TGP-H-090”, thickness of about 300 μm, manufactured by Toray Industries, Inc.) subjected to water repellent treatment was prepared. Then, the carbon paper was immersed in a diluted PTFE (polytetrafluoroethylene) dispersion (trade name “D-1”, manufactured by Daikin Industries, Ltd.) for 1 minute. Next, the carbon paper was dried in a hot air dryer set at a temperature of 100 ° C. The carbon paper after drying was fired at 270 ° C. for 2 hours in an electric furnace. In this way, an anode porous substrate 34 having a PTFE content of 10% by weight was produced.
（カソード多孔質基材の作製）
　カーボンクロス（商品名「ＡｖＣａｒｂ（商標）１０７１ＨＣＢ」、バラードマテリアルプロダクツ社製）を用意した。そして、該カーボンクロスに対して、アノード多孔質基材３４を作製する際に用いた処理と同様の処理を施すことにより、ＰＴＦＥの含有量が１０重量％であるカソード多孔質基材４４を作製した。 (Production of cathode porous substrate)
Carbon cloth (trade name “AvCarb ™ 1071HCB”, manufactured by Ballard Material Products) was prepared. Then, a cathode porous base material 44 having a PTFE content of 10% by weight is prepared by subjecting the carbon cloth to the same treatment as that used when the anode porous base material 34 is produced. did.
（アノード撥水層の形成）
　アセチレンブラックの粉末と、ＰＴＦＥのディスパージョン（商品名「Ｄ－１」、ダイキン工業（株）製）とを用意した。そして、これらを攪拌機によって攪拌して混合し、これにより撥水層形成用インクを作製した。尚、この撥水層形成用インクにおいて、全固形分に占めるＰＴＦＥ及びアセチレンブラックの含有量はそれぞれ、１０重量％及び９０重量％であった。 (Formation of anode water repellent layer)
Acetylene black powder and PTFE dispersion (trade name “D-1”, manufactured by Daikin Industries, Ltd.) were prepared. And these were stirred and mixed by the stirrer, and thereby the water repellent layer forming ink was produced. In this water repellent layer forming ink, the contents of PTFE and acetylene black in the total solid content were 10 wt% and 90 wt%, respectively.
　次に、エアーブラシを使用したスプレー法により、アノード多孔質基材３４の一方の表面に撥水層形成用インクを塗布した。これにより、アノード多孔質基材３４の表面に、撥水層形成用インクの塗布膜を形成した。その後、１００℃に温度設定された恒温槽内にアノード多孔質基材３４を置き、撥水層形成用インクの塗布膜を乾燥させた。更にその後、撥水層形成用インクの塗布膜を、アノード多孔質基材３４と共に、電気炉によって２７０℃で２時間、焼成した。この様にして、アノード多孔質基材３４上にアノード撥水層３２を形成し、これによりアノード拡散層３０を作製した。 Next, the water repellent layer forming ink was applied to one surface of the anode porous substrate 34 by a spray method using an air brush. As a result, a water-repellent layer forming ink coating film was formed on the surface of the anode porous substrate 34. Thereafter, the anode porous substrate 34 was placed in a thermostat set at 100 ° C., and the coating film of the water repellent layer forming ink was dried. Thereafter, the coating film of the water repellent layer forming ink was baked at 270 ° C. for 2 hours in the electric furnace together with the anode porous substrate 34. In this manner, the anode water repellent layer 32 was formed on the anode porous substrate 34, and thereby the anode diffusion layer 30 was produced.
（カソード撥水層の形成）
　アノード撥水層３２の形成方法と同様の方法を用いて、カソード多孔質基材４４の一方の表面にカソード撥水層４２を形成し、これによりカソード拡散層４０を作製した。 (Formation of cathode water repellent layer)
A cathode water repellent layer 42 was formed on one surface of the cathode porous substrate 44 by using a method similar to the method for forming the anode water repellent layer 32, thereby producing the cathode diffusion layer 40.
（ＭＥＡの作製）
　抜き型を使用して、アノード拡散層３０及びカソード拡散層４０を何れも、４０ｍｍ×９０ｍｍの長方形に成形した。 (Production of MEA)
Both the anode diffusion layer 30 and the cathode diffusion layer 40 were formed into a 40 mm × 90 mm rectangle using a punching die.
　次に、アノード拡散層３０のアノード撥水層３２と、ＣＣＭのアノード触媒層２８とが接する様に、アノード拡散層３０とＣＣＭとを積層した。また、カソード拡散層４０のカソード撥水層４２と、ＣＣＭのカソード触媒層３８とが接する様に、カソード拡散層４０とＣＣＭとを積層した。 Next, the anode diffusion layer 30 and the CCM were laminated so that the anode water repellent layer 32 of the anode diffusion layer 30 and the anode catalyst layer 28 of CCM were in contact with each other. The cathode diffusion layer 40 and the CCM were laminated so that the cathode water-repellent layer 42 of the cathode diffusion layer 40 and the cathode catalyst layer 38 of CCM were in contact with each other.
　得られた積層体を、１２５℃に温度設定された熱プレス装置を用いて、５ＭＰａの圧力で１分間、加圧した。これにより、アノード触媒層２８とアノード拡散層３０とを互いに接合させる共に、カソード触媒層３８とカソード拡散層４０とを互いに接合させた。この様にして、ＭＥＡを作製した。 The obtained laminate was pressurized at a pressure of 5 MPa for 1 minute using a hot press apparatus set at 125 ° C. As a result, the anode catalyst layer 28 and the anode diffusion layer 30 were joined together, and the cathode catalyst layer 38 and the cathode diffusion layer 40 were joined together. Thus, MEA was produced.
　３．単位セルの作製
（ガスケットの配置）
　厚み０．２５ｍｍのエチレンプロピレンジエンゴム（ＥＰＤＭ）のシートを用意し、これを５０ｍｍ×１２０ｍｍの長方形に裁断した。更に、このシートには、その中央部分をくり抜くことにより、４２ｍｍ×９２ｍｍのサイズの開口部を形成した。この様にして、２枚のガスケット５２及び５４を作製した。 3. Production of unit cells (gasket arrangement)
A sheet of ethylene propylene diene rubber (EPDM) with a thickness of 0.25 mm was prepared and cut into a 50 mm × 120 mm rectangle. Further, an opening having a size of 42 mm × 92 mm was formed in the sheet by hollowing out the central portion. In this way, two gaskets 52 and 54 were produced.
　そして、一方のガスケット５２の開口部にはＭＥＡのアノードが嵌め込まれ、且つ他方のガスケット５４の開口部にはＭＥＡのカソードが嵌め込まれることとなる様に、ＭＥＡに対してガスケット５２及び５４を配置した。 The gaskets 52 and 54 are arranged with respect to the MEA so that the anode of the MEA is fitted into the opening of one gasket 52 and the cathode of the MEA is fitted into the opening of the other gasket 54. did.
（セパレータの作製）
　アノード側セパレータ３６の素材として、厚み１．５ｍｍ、サイズ５０ｍｍ×１２０ｍｍの長方形の樹脂含浸黒鉛板を準備した。そして、この黒鉛板の表面を切削することによって該表面に溝を形成し、これにより液体燃料であるメタノールをアノードに供給するための燃料流路４８を形成した。黒鉛板の一方の短辺側端部には燃料流路４８の入口を形成し、黒鉛板の他方の短辺側端部には燃料流路４８の出口を形成した。この様にして、アノード側セパレータ３６を作製した。 (Preparation of separator)
As a material for the anode separator 36, a rectangular resin-impregnated graphite plate having a thickness of 1.5 mm and a size of 50 mm × 120 mm was prepared. Then, the surface of the graphite plate was cut to form a groove on the surface, thereby forming a fuel flow path 48 for supplying methanol, which is a liquid fuel, to the anode. The inlet of the fuel channel 48 was formed at one short side end of the graphite plate, and the outlet of the fuel channel 48 was formed at the other short side end of the graphite plate. In this way, an anode side separator 36 was produced.
　カソード側セパレータ４６の素材として、厚み２ｍｍ、サイズ５０ｍｍ×１２０ｍｍの樹脂含浸黒鉛板を準備した。そして、この黒鉛板の表面を切削することによって該表面に溝を形成し、これにより酸化剤である空気をカソードに供給するための酸化剤流路５０を形成した。黒鉛板の一方の短辺側端部には酸化剤流路５０の入口を形成し、黒鉛板の他方の短辺側端部には酸化剤流路５０の出口を形成した。この様にして、カソード側セパレータ４６を作製した。 As a material for the cathode separator 46, a resin-impregnated graphite plate having a thickness of 2 mm and a size of 50 mm × 120 mm was prepared. Then, the surface of the graphite plate was cut to form grooves on the surface, thereby forming an oxidant flow path 50 for supplying air as an oxidant to the cathode. The inlet of the oxidant channel 50 was formed at one short side end of the graphite plate, and the outlet of the oxidant channel 50 was formed at the other short side end of the graphite plate. In this way, a cathode side separator 46 was produced.
　燃料流路４８及び酸化剤流路５０である溝の断面サイズは何れも、幅１ｍｍ、深さ０．５ｍｍとした。又、アノード拡散層３０及びカソード拡散層４０の各部に液体燃料及び酸化剤をそれぞれ満遍なく供給するべく、燃料流路４８及び酸化剤流路５０の形状をサーペンタイン型にした。 The cross-sectional sizes of the grooves that are the fuel flow path 48 and the oxidant flow path 50 are both 1 mm wide and 0.5 mm deep. Further, in order to supply the liquid fuel and the oxidant uniformly to each part of the anode diffusion layer 30 and the cathode diffusion layer 40, the shape of the fuel channel 48 and the oxidant channel 50 is a serpentine type.
（単位セルの作製）
　アノード側セパレータ３６は、ＭＥＡのアノード拡散層３０上に、燃料流路４８をアノード拡散層３０の方へ向けた姿勢で積層した。一方、カソード側セパレータ４６は、ＭＥＡのカソード拡散層４０上に、酸化剤流路５０をカソード拡散層４０の方へ向けた姿勢で積層した。この様にして、単位セル２０を作製した。 (Production of unit cell)
The anode separator 36 was laminated on the MEA anode diffusion layer 30 in a posture in which the fuel flow channel 48 was directed toward the anode diffusion layer 30. On the other hand, the cathode separator 46 was laminated on the MEA cathode diffusion layer 40 in such a posture that the oxidant flow path 50 was directed toward the cathode diffusion layer 40. In this way, the unit cell 20 was produced.
　４．セルスタックの作製
　６個の単位セル２０を用意し、これらを積層した。そして、単位セル２０の積層方向において、単位セル２０の積層体の両端に、厚さ１ｃｍのステンレス鋼板からなる一対の端板を配置した。各端板と、これに対応するセパレータとの間には、表面に金メッキが施された厚さ２ｍｍの銅板からなる集電板と、絶縁板とを配置した。このとき、セパレータ側に集電板を配置し、端板側に絶縁板を配置した。 4). Production of Cell Stack Six unit cells 20 were prepared and laminated. Then, in the stacking direction of the unit cells 20, a pair of end plates made of a stainless steel plate having a thickness of 1 cm were disposed at both ends of the stacked body of the unit cells 20. Between each end plate and the corresponding separator, a current collector plate made of a copper plate having a thickness of 2 mm with a gold plating on the surface and an insulating plate were arranged. At this time, the current collector plate was disposed on the separator side, and the insulating plate was disposed on the end plate side.
　その状態で、一対の端板を、ボルト、ナット、及びばねを用いて互いに締結し、これにより各単位セル２０においてアノード側セパレータ３６及びカソード側セパレータ４６をＭＥＡへ押し付けた。この様にして、サイズが５０ｍｍ×１２０ｍｍであるＤＭＦＣ用のセルスタック１３を作製した。 In this state, the pair of end plates were fastened to each other using bolts, nuts, and springs, thereby pressing the anode side separator 36 and the cathode side separator 46 against the MEA in each unit cell 20. In this way, a cell stack 13 for DMFC having a size of 50 mm × 120 mm was produced.
　５．燃料電池システムの作製
　単位セル２０の酸化剤流路５０の入口は、セルスタック１３の１つの側面に沿って並んでいる。そこで、該側面が酸化剤チャンバ１７の側壁と対向する様に、セルスタック１３を燃料電池ケース２ａ内に配置した。そして、酸化剤チャンバ１７の側壁には、酸化剤入口１８となる複数の貫通孔を酸化剤流路５０の入口に対応させて設け、これにより酸化剤チャンバ１７と酸化剤流路５０とを互いに連通させた。 5. Production of Fuel Cell System The inlets of the oxidant flow paths 50 of the unit cells 20 are arranged along one side surface of the cell stack 13. Therefore, the cell stack 13 is disposed in the fuel cell case 2 a so that the side surface faces the side wall of the oxidant chamber 17. A plurality of through holes serving as the oxidant inlet 18 are provided in the side wall of the oxidant chamber 17 so as to correspond to the inlet of the oxidant flow path 50, whereby the oxidant chamber 17 and the oxidant flow path 50 are mutually connected. Communicated.
　次に、酸化剤をＤＭＦＣ２に供給するための構成を次のように作製した。各単位セル２０の酸化剤入口１８にシリコンチューブを差し込むと共に、これらのシリコンチューブを分岐管によって合流させ、これにより１つの流路を形成した。そして、この流路の先端を、圧縮空気を供給する高圧空気ボンベに接続した。又、この流路には、圧縮空気の流量を調節するマスフローコントローラ（堀場製作所（株）製）を設けた。尚、本実施例においては、高圧空気ボンベとマスフローコントローラとによって、酸化剤ポンプ部８が構成されている。 Next, a configuration for supplying the oxidizing agent to DMFC 2 was produced as follows. A silicon tube was inserted into the oxidant inlet 18 of each unit cell 20 and these silicon tubes were joined by a branch pipe, thereby forming one flow path. And the front-end | tip of this flow path was connected to the high pressure air cylinder which supplies compressed air. In addition, a mass flow controller (manufactured by Horiba, Ltd.) for adjusting the flow rate of the compressed air was provided in this flow path. In the present embodiment, the oxidant pump unit 8 is constituted by a high-pressure air cylinder and a mass flow controller.
　ＤＭＦＣ２にて生成された水や消費されずに残った酸化剤を回収するための構成は、次のように作製した。各単位セル２０の酸化剤流路５０の出口にシリコンチューブを差し込むと共に、これらのシリコンチューブを分岐管によって合流させ、これにより１つの流路を作製した。そして、この流路の先端を酸化剤出口１６に接続した。更に、酸化剤出口１６と回収タンク５とを、別のシリコンチューブ（排出管１０９）によって接続した。 The structure for recovering the water generated in DMFC2 and the oxidant remaining without being consumed was prepared as follows. A silicon tube was inserted into the outlet of the oxidant flow path 50 of each unit cell 20, and these silicon tubes were joined by a branch pipe, thereby producing one flow path. Then, the tip of this flow path was connected to the oxidant outlet 16. Further, the oxidant outlet 16 and the recovery tank 5 were connected by another silicon tube (discharge pipe 109).
　液体燃料をＤＭＦＣ２に供給するための構成を次のように作製した。各単位セル２０の燃料流路４８の入口にシリコンチューブを差し込むと共に、これらのシリコンチューブを分岐管によって合流させ、これにより１つの流路を作製した。そして、この流路の先端を、燃料ポンプ部４に接続した。燃料ポンプ部４には、精密ポンプ（製品名「パーソナルポンプＮＰ－ＫＸ－１００」、日本精密科学（株）製）を用いた。本実施例では、燃料ポンプ部４は、燃料電池ケース２ａ外に設けた。 A configuration for supplying liquid fuel to the DMFC 2 was produced as follows. A silicon tube was inserted into the inlet of the fuel flow path 48 of each unit cell 20, and these silicon tubes were joined by a branch pipe, thereby producing one flow path. Then, the tip of this flow path was connected to the fuel pump unit 4. A precision pump (product name “Personal Pump NP-KX-100”, manufactured by Japan Precision Science Co., Ltd.) was used for the fuel pump section 4. In this embodiment, the fuel pump unit 4 is provided outside the fuel cell case 2a.
　ＤＭＦＣ２から排出される燃料排液を回収するための構成は、次のように作製した。各単位セル２０の燃料流路４８の出口にシリコンチューブを差し込むと共に、これらのシリコンチューブを分岐管によって合流させ、これにより１つの流路を作製した。そして、この流路の先端を、燃料出口１４に接続した。更に、燃料出口１４と回収タンク５とを、別のシリコンチューブ（排出管１９）によって接続した。 The configuration for recovering the fuel drainage discharged from the DMFC 2 was produced as follows. A silicon tube was inserted into the outlet of the fuel flow path 48 of each unit cell 20, and these silicon tubes were joined by a branch pipe, thereby producing one flow path. Then, the tip of this flow path was connected to the fuel outlet 14. Furthermore, the fuel outlet 14 and the collection tank 5 were connected by another silicon tube (discharge pipe 19).
　６．条件設定
　制御部１１によって燃料ポンプ部４を制御することにより、液体燃料であるメタノール水溶液の供給量を、０．０８３ｃｍ3／ｍｉｎ・ｃｍ2とした。又、制御部１１によってマスフローコントローラを制御することにより、酸化剤である空気（無加湿）の供給量を、８３．３ｃｍ3／ｍｉｎ・ｃｍ2とした。 6). Condition setting By controlling the fuel pump unit 4 with the control unit 11, the supply amount of the methanol aqueous solution as the liquid fuel was set to 0.083 cm 3 / min · cm 2 . Further, by controlling the mass flow controller by the control unit 11, the supply amount of air (non-humidified) as an oxidizer was set to 83.3 cm 3 / min · cm 2 .
　又、ＤＭＦＣ２の正極外部端子６及び負極外部端子７には、ＤＣ／ＤＣコンバータ９を介して、電子負荷装置（製品名「ＰＬＺ１６４ＷＡ」、菊水電子工業（株）製）を接続した。そして、この電子負荷装置に流れる電流の密度が２００ｍＡ／ｃｍ2で一定となる様に、ＤＭＦＣ２から出力される電流を調整した。又、ＯＣＶとして、セルスタック１３の電圧を用いた。そして、通常運転を開始するためのＯＣＶの所定値を４．５Ｖに設定した。更に、所定時間Ｔ１及びＴ２をそれぞれ、３０秒及び１分に設定した。この様な条件の下で、上述した発電準備制御を本実施例の燃料電池システムにて実行した。 An electronic load device (product name “PLZ164WA”, manufactured by Kikusui Electronics Co., Ltd.) was connected to the positive external terminal 6 and the negative external terminal 7 of the DMFC 2 via a DC / DC converter 9. Then, the current output from the DMFC 2 was adjusted so that the density of the current flowing through the electronic load device was constant at 200 mA / cm 2 . Moreover, the voltage of the cell stack 13 was used as OCV. And the predetermined value of OCV for starting a normal driving | operation was set to 4.5V. Further, the predetermined times T1 and T2 were set to 30 seconds and 1 minute, respectively. Under such conditions, the power generation preparation control described above was executed in the fuel cell system of this example.
　７．結果
　図５は、上述した条件の下で発電準備制御を実行した結果を示した図である。図５では、経過時間に対するＯＣＶの変化が、グラフによって示されている。尚、発電準備制御は、発電を停止した状態で２４時間が経過した後に、ＤＣ／ＤＣコンバータ９と電子負荷装置のスイッチをオンにして開始した。 7). Result FIG. 5 is a diagram illustrating a result of executing the power generation preparation control under the above-described conditions. In FIG. 5, the change of OCV with respect to elapsed time is shown by the graph. The power generation preparation control was started by turning on the DC / DC converter 9 and the electronic load device after 24 hours had elapsed with the power generation stopped.
　制御が始まって液体燃料及び酸化剤の供給が開始された後（Ｓ１００）、２０秒が経過するとＯＣＶが３．６Ｖまで上昇する一方で、その後の１０秒間は電圧が殆ど上昇しなかった。このため、液体燃料及び酸化剤の供給が開始された時点から所定時間Ｔ１（＝３０秒）が経過する迄の間にＯＣＶが所定値（＝４．５Ｖ）以上とならず（Ｓ１０３にてＹｅｓ判定）、従って液体燃料及び酸化剤の供給が停止された（Ｓ１０４）。液体燃料及び酸化剤の供給が停止された時点から所定時間Ｔ２（＝１分）が経過すると（Ｓ１０５にてＹｅｓ判定）、液体燃料及び酸化剤の２回目の供給が開始された（Ｓ１００）。 After the control was started and the supply of the liquid fuel and the oxidant was started (S100), the OCV increased to 3.6V after 20 seconds, while the voltage hardly increased for the subsequent 10 seconds. For this reason, the OCV does not become equal to or higher than the predetermined value (= 4.5V) until the predetermined time T1 (= 30 seconds) elapses after the supply of the liquid fuel and the oxidant is started (Yes in S103). Determination), therefore, the supply of the liquid fuel and the oxidant was stopped (S104). When a predetermined time T2 (= 1 minute) has elapsed since the supply of the liquid fuel and the oxidant was stopped (Yes in S105), the second supply of the liquid fuel and the oxidant was started (S100).
　液体燃料及び酸化剤の２回目の供給が開始された後（Ｓ１００）、２０秒が経過するとＯＣＶが４．３５Ｖまで上昇する一方で、その後の１０秒間は電圧が殆ど上昇しなかった。このため、液体燃料及び酸化剤の供給が開始された時点から所定時間Ｔ１（＝３０秒）が経過する迄の間にＯＣＶが所定値（＝４．５Ｖ）以上とならず（Ｓ１０３にてＹｅｓ判定）、従って液体燃料及び酸化剤の供給が再び停止された（Ｓ１０４）。液体燃料及び酸化剤の供給が停止された時点から所定時間Ｔ２（＝１分）が経過すると（Ｓ１０５にてＹｅｓ判定）、液体燃料及び酸化剤の３回目の供給が開始された（Ｓ１００）。 After the second supply of the liquid fuel and the oxidant was started (S100), the OCV increased to 4.35V after 20 seconds, while the voltage hardly increased for the subsequent 10 seconds. For this reason, the OCV does not become equal to or higher than the predetermined value (= 4.5V) until the predetermined time T1 (= 30 seconds) elapses after the supply of the liquid fuel and the oxidant is started (Yes in S103). Determination), therefore, the supply of the liquid fuel and the oxidant was stopped again (S104). When a predetermined time T2 (= 1 minute) has elapsed since the supply of the liquid fuel and the oxidant was stopped (Yes in S105), the third supply of the liquid fuel and the oxidant was started (S100).
　液体燃料及び酸化剤の３回目の供給が開始された後（Ｓ１００）、２０秒が経過するとＯＣＶが５．１Ｖまで上昇した。このため、ＯＣＶが所定値（＝４．５Ｖ）以上となり（Ｓ１０１にてＹｅｓ判定）、これにより通常運転が開始された（Ｓ１０２）。そして、ＤＭＦＣ２の出力は２０Ｗに到達し、目標を達成することができた。 After the third supply of liquid fuel and oxidizer was started (S100), OCV rose to 5.1V after 20 seconds. Therefore, the OCV becomes equal to or higher than a predetermined value (= 4.5V) (Yes determination in S101), and thereby normal operation is started (S102). The output of DMFC2 reached 20 W, and the target could be achieved.
　（比較例）
　本比較例では、上記実施例と同じ構成の燃料電池システムを用いた。又、液体燃料及び酸化剤の供給量、並びにＤＭＦＣ２から出力される電流を、上記実施例の条件と同じにした。一方、所定時間Ｔ１を無限大に設定した。 (Comparative example)
In this comparative example, a fuel cell system having the same configuration as the above example was used. Further, the supply amounts of the liquid fuel and the oxidant and the current output from the DMFC 2 were made the same as the conditions of the above embodiment. On the other hand, the predetermined time T1 is set to infinity.
　図６は、本比較例の条件の下で発電準備制御を実行した結果を示した図である。図６では、経過時間に対するＯＣＶの変化が、グラフによって示されている。尚、発電準備制御は、発電を停止した状態で２４時間が経過した後に、ＤＣ／ＤＣコンバータ９と電子負荷装置のスイッチをオンにして開始した。 FIG. 6 is a diagram showing a result of executing power generation preparation control under the conditions of this comparative example. In FIG. 6, the change of OCV with respect to elapsed time is shown by the graph. The power generation preparation control was started by turning on the DC / DC converter 9 and the electronic load device after 24 hours had elapsed with the power generation stopped.
　制御が始まって液体燃料及び酸化剤の供給が開始された後（Ｓ１００）、２０秒が経過するとＯＣＶが３．６Ｖまで上昇する一方で、その後は電圧が殆ど上昇しなかった。具体的には、液体燃料及び酸化剤の供給が開始された後、１０分２０秒が経過したときのＯＣＶを測定したところ、ＯＣＶは３．８Ｖに過ぎなかった。そして、ＯＣＶは所定値に到達しなかった。 After the control was started and the supply of the liquid fuel and the oxidant was started (S100), the OCV increased to 3.6V after 20 seconds, while the voltage hardly increased thereafter. Specifically, when the OCV was measured when 10 minutes and 20 seconds passed after the supply of the liquid fuel and the oxidant was started, the OCV was only 3.8V. The OCV did not reach a predetermined value.
　他の比較例として、ＯＣＶの所定値を３．６Ｖに設定した。この場合、通常運転が開始されるが、ＤＭＦＣ２の出力は１３Ｗにしかならず、目標の２０Ｗを達成することができなかった。更に発電を継続すると、一部の単位セル２０において電圧が０．２Ｖ以下にまで低下した。このため、発電を停止した。 As another comparative example, the predetermined value of OCV was set to 3.6V. In this case, normal operation is started, but the output of DMFC2 is only 13 W, and the target of 20 W cannot be achieved. When power generation was further continued, the voltage in some unit cells 20 dropped to 0.2 V or less. For this reason, power generation was stopped.
　比較例の結果から、燃料電池システムにおいてカソード側の水詰まりを解消せず通常運転を行うと、ＤＭＦＣ２の発電性能が低下すると共に、発電中に水詰まりが増大して継続的に発電することが困難になることが分かった。一方、実施例の結果から、カソード側の水詰まりが解消された状態で通常運転を開始することにより、ＤＭＦＣ２の発電性能の低下が抑制されることが分かった。 From the results of the comparative example, when the normal operation is performed without eliminating the clogging on the cathode side in the fuel cell system, the power generation performance of the DMFC 2 decreases, and the clogging increases during power generation, so that the power generation is continued. It turned out to be difficult. On the other hand, from the results of the examples, it was found that a decrease in the power generation performance of the DMFC 2 was suppressed by starting normal operation in a state where the clogging on the cathode side was eliminated.
　本発明を現時点での好ましい実施態様に関して説明したが、そのような開示を限定的に解釈してはならない。種々の変形および改変は、上記開示を読むことによって本発明に属する技術分野における当業者には間違いなく明らかになるであろう。したがって、添付の特許請求の範囲は、本発明の真の精神および範囲から逸脱することなく、すべての変形及び改変を包含する、と解釈されるべきものである。 Although the present invention has been described in terms of the presently preferred embodiments, such disclosure should not be construed as limiting. Various changes and modifications will no doubt become apparent to those skilled in the art to which the present invention pertains after reading the above disclosure. Accordingly, the appended claims should be construed to include all variations and modifications without departing from the true spirit and scope of the invention.
　本発明の燃料電池システムは、例えば、ノート型パーソナルコンピュータ、携帯電話機、携帯情報端末（ＰＤＡ）などの携帯小型電子機器の電源として有用である。又、本発明の燃料電池システムは、電動スクータ用電源などの用途にも応用することができる。 The fuel cell system of the present invention is useful as a power source for portable small electronic devices such as notebook personal computers, mobile phones, and personal digital assistants (PDAs). The fuel cell system of the present invention can also be applied to uses such as a power source for electric scooters.
１　燃料電池システム
２　ＤＭＦＣ
２ａ　燃料電池ケース
３　燃料タンク
４　燃料ポンプ部
５　回収タンク
６　正極外部端子
７　負極外部端子
８　酸化剤ポンプ部
９　ＤＣ／ＤＣコンバータ
１０　蓄電部
１１　制御部
１２　電圧検出部
１３　セルスタック
１４　燃料出口
１６　酸化剤出口
１７　酸化剤チャンバ
１８　酸化剤入口
１９　排出管
２０　単位セル
２２　高分子電解質膜
２４　アノード
２６　カソード
３６　アノード側セパレータ
４６　カソード側セパレータ
４８　燃料流路
５０　酸化剤流路
５１　燃料入口
１０１　液体燃料
１０２　二酸化炭素
１０３　酸化剤（空気）
１０４　水
１０９　排出管
Ｔ１，Ｔ２　所定時間 1 Fuel cell system 2 DMFC
2a Fuel cell case 3 Fuel tank 4 Fuel pump unit 5 Collection tank 6 Positive external terminal 7 Negative external terminal 8 Oxidant pump unit 9 DC / DC converter 10 Power storage unit 11 Control unit 12 Voltage detection unit 13 Cell stack 14 Fuel outlet 16 Oxidation Oxidant outlet 17 Oxidant chamber 18 Oxidant inlet 19 Discharge pipe 20 Unit cell 22 Polymer electrolyte membrane 24 Anode 26 Cathode 36 Anode side separator 46 Cathode side separator 48 Fuel flow path 50 Oxidant flow path 51 Fuel inlet 101 Liquid fuel 102 Dioxide Carbon 103 oxidizer (air)
104 Water 109 Discharge pipe T1, T2 Predetermined time

Claims (7)

  1. 　燃料電池と、
    　前記燃料電池に液体燃料を供給する燃料ポンプ部と、
    　前記燃料電池に酸化剤を供給する酸化剤ポンプ部と、
    　前記燃料ポンプ部及び前記酸化剤ポンプ部を制御する制御部と、
    　前記燃料電池の開回路電圧を検出する電圧検出部と
    を備え、前記制御部は、前記燃料電池での発電起動時の準備運転において、前記燃料電池への液体燃料及び酸化剤の供給をそれぞれ前記燃料ポンプ部及び前記酸化剤ポンプ部に開始させた後、酸化剤の供給開始から第１の所定時間が経過する迄に前記開回路電圧が所定値以上とならなかった場合、前記燃料電池への酸化剤の供給を前記酸化剤ポンプ部に停止させる第１制御を実行し、その後、酸化剤の供給停止から第２の所定時間が経過したときに、前記燃料電池への酸化剤の供給を前記酸化剤ポンプ部に再び開始させる第２制御を実行する、燃料電池システム。     A fuel cell;
    A fuel pump for supplying liquid fuel to the fuel cell;
    An oxidant pump for supplying an oxidant to the fuel cell;
    A control unit for controlling the fuel pump unit and the oxidant pump unit;
    A voltage detection unit that detects an open circuit voltage of the fuel cell, and the control unit supplies the liquid fuel and the oxidant to the fuel cell, respectively, in a preparatory operation at the time of power generation startup in the fuel cell. After the fuel pump unit and the oxidant pump unit are started, when the open circuit voltage does not become a predetermined value or more before the first predetermined time elapses from the start of the supply of the oxidant, The first control for stopping the supply of the oxidant to the oxidant pump unit is executed, and then the supply of the oxidant to the fuel cell is performed when the second predetermined time has elapsed since the supply of the oxidant was stopped. A fuel cell system that executes a second control that causes the oxidant pump unit to start again.
  2. 　前記制御部は、前記開回路電圧が前記所定値以上になる迄、前記第１制御と前記第２制御とを繰り返し実行する、請求項１に記載の燃料電池システム。 2. The fuel cell system according to claim 1, wherein the control unit repeatedly executes the first control and the second control until the open circuit voltage becomes equal to or higher than the predetermined value.
  3. 　前記制御部は、酸化剤の供給開始から第１の所定時間が経過する迄に前記開回路電圧が所定値以上になった場合、前記燃料電池での通常運転を開始する、請求項１又は請求項２に記載の燃料電池システム。 The control unit starts normal operation in the fuel cell when the open circuit voltage becomes a predetermined value or more before the first predetermined time elapses from the start of supply of the oxidant. Item 3. The fuel cell system according to Item 2.
  4. 　前記燃料電池は、複数の単位セルが直列に接続されたセルスタックを有し、前記電圧検出部は、セルスタックの電圧、何れか１つの単位セルの電圧、又は幾つかの単位セルの積層体の電圧の少なくとも何れか１つを、前記開回路電圧として検出する、請求項１乃至請求項３の何れかに記載の燃料電池システム。 The fuel cell includes a cell stack in which a plurality of unit cells are connected in series, and the voltage detection unit includes a voltage of the cell stack, a voltage of any one unit cell, or a stack of several unit cells. The fuel cell system according to any one of claims 1 to 3, wherein at least one of the voltages is detected as the open circuit voltage.
  5. 　前記開回路電圧の所定値は、１つの単位セルあたりの電圧で０．７５Ｖ以上に設定されている、請求項１乃至請求項４の何れかに記載の燃料電池システム。 The fuel cell system according to any one of claims 1 to 4, wherein the predetermined value of the open circuit voltage is set to 0.75 V or more as a voltage per unit cell.
  6. 　前記燃料電池は、直接酸化型燃料電池であり、前記液体燃料は、メタノール、エタノール、蟻酸、ホルムアルデヒド、ジメチルエーテル、及びエチレングリコールよりなる群から選択される少なくとも１種類の燃料を含む、請求項１乃至請求項５の何れかに記載の燃料電池システム。 The fuel cell is a direct oxidation fuel cell, and the liquid fuel includes at least one fuel selected from the group consisting of methanol, ethanol, formic acid, formaldehyde, dimethyl ether, and ethylene glycol. The fuel cell system according to claim 5.
  7. 　前記制御部は、前記第１制御において、前記燃料電池への酸化剤の供給を前記酸化剤ポンプ部に停止させると共に、前記燃料電池への液体燃料の供給を前記燃料ポンプ部に停止させ、且つ、前記第２制御において、前記燃料電池への酸化剤の供給を前記酸化剤ポンプ部に再び開始させると共に、前記燃料電池への液体燃料の供給を前記燃料ポンプ部に再び開始させる、請求項１乃至請求項６の何れかに記載の燃料電池システム。 In the first control, the control unit stops the supply of the oxidant to the fuel cell to the oxidant pump unit, stops the supply of the liquid fuel to the fuel cell to the fuel pump unit, and 2. In the second control, the supply of oxidant to the fuel cell is restarted by the oxidant pump unit, and the supply of liquid fuel to the fuel cell is restarted by the fuel pump unit. The fuel cell system according to claim 6.
PCT/JP2012/004722 2011-09-30 2012-07-24 Fuel cell system WO2013046519A1 (en)

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JP2006140104A (en) * 2004-11-15 2006-06-01 Toyota Motor Corp Tube type fuel cell device and operation method of tube type fuel cell
JP2006278264A (en) * 2005-03-30 2006-10-12 Toshiba Corp Fuel cell system
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CN111029627B (en) * 2018-10-05 2023-04-14 丰田自动车株式会社 Fuel cell system

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