WO2021100247A1 - Capacity recovering method and manufacturing method for secondary battery - Google Patents

Capacity recovering method and manufacturing method for secondary battery Download PDF

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Publication number
WO2021100247A1
WO2021100247A1 PCT/JP2020/028409 JP2020028409W WO2021100247A1 WO 2021100247 A1 WO2021100247 A1 WO 2021100247A1 JP 2020028409 W JP2020028409 W JP 2020028409W WO 2021100247 A1 WO2021100247 A1 WO 2021100247A1
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Prior art keywords
secondary battery
capacity
electrode
positive electrode
discharge
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PCT/JP2020/028409
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French (fr)
Japanese (ja)
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耕平 本蔵
栄二 關
杉政　昌俊
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株式会社日立ハイテク
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/392—Determining battery ageing or deterioration, e.g. state of health
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • 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
    • Y02E60/10—Energy storage using batteries
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a method for recovering the capacity of a secondary battery and a method for manufacturing the secondary battery.
  • Lithium-ion batteries are one of the non-aqueous electrolyte secondary batteries, and because of their high energy density, they are also used as batteries for portable devices and, in recent years, as batteries for electric vehicles. However, it is known that a lithium ion battery deteriorates with use and the battery capacity decreases.
  • a lithium metal oxide is generally used as the active material for the positive electrode
  • a carbon material such as graphite is generally used as the active material for the negative electrode.
  • the positive electrode and the negative electrode of the lithium ion battery are formed by adding a binder, a conductive agent, or the like to a group of minute active material particles to form a slurry, and then applying the mixture to a metal foil.
  • the lithium ions released from the active material of the positive electrode are occluded in the active material of the negative electrode, and at the time of discharging, the lithium ions stored in the active material of the negative electrode are occluded and stored in the active material of the positive electrode. In this way, the lithium ions move between the electrodes, causing a current to flow between the electrodes.
  • the capacity is reduced by (1) electrical isolation of the positive electrode active material, (2) electrical isolation of the negative electrode active material, and (3) immobilization of lithium ions moving back and forth between the electrodes. To do.
  • a lithium ion battery having a third electrode containing lithium inside is manufactured, and lithium ions are replenished from the third electrode to the positive electrode or the negative electrode. By doing so, it is possible to recover the reduced capacity.
  • lithium ions that cannot be completely occluded in the negative electrode active material during charging will be deposited as lithium metal, or the lithium ion concentration in the positive electrode active material will be excessive during discharge, resulting in an excessive amount of lithium ions in the battery. Problems such as promoting deterioration of characteristics occur. In such a case, the lithium ion battery may become unsafe or the capacity recovery may be insufficient.
  • Patent Document 1 describes the first active material and an electrode rather than the first active material, with an object of replenishing an appropriate amount of lithium ions that suppress the formation of lithium dendrite to recover the capacity of the lithium ion battery.
  • a method for recovering the capacity of a lithium ion battery including a positive electrode containing a second active material having a low potential, a negative electrode, an electrolyte solution, and a lithium ion replenishment electrode (third electrode) that emits lithium ions.
  • the first plateau region which is a region where the charge / discharge voltage holds the electrode potential corresponding to the first active material, and the region where the charge / discharge voltage holds the electrode potential corresponding to the second active material. Based on the length with the second plateau region, it is determined that the cause of deterioration is a decrease in lithium ions in a predetermined case, and an appropriate amount of lithium ions from the third electrode is disclosed.
  • Patent Document 2 in order to detect the status of the positive electrode and the status of the negative electrode inside the secondary battery by a non-destructive and simple method, the positive electrode effective active material amount m p and the negative electrode are as correction parameters.
  • the secondary battery was charged and discharged with a minute current using the amount of effective active material m n , the index C p of the positional relationship of the discharge curve of the positive electrode, and the index C n of the positional relationship of the discharge curve of the negative electrode.
  • a method of reproducing the charge / discharge curve of the secondary battery obtained in the case by superimposing the charge / discharge curves of the positive electrode alone and the negative electrode alone measured separately is disclosed.
  • Non-Patent Document 1 the charge / discharge cycle is repeated from the initial state as a deterioration mechanism of the LiCoO 2 / graphite cell in the charge / discharge cycle using the discharge curve analysis that separates the discharge curve into the discharge curves of the positive electrode and the negative electrode.
  • , the change in capacitance from the initial value for the cell, positive electrode and negative electrode, and the irreversible lithium ion loss, etc. Is being considered.
  • Non-Patent Document 1 describes that the maximum value of
  • Non-Patent Document 2 describes a method of analyzing the VQ curve of a high-power lithium-ion battery using the extreme value of the derivative dV / dQ curve.
  • the capacity recovery method of the lithium ion battery described in Patent Document 1 relates to a case where two types of positive electrode active materials having different reaction potentials are used, and the degree of freedom in material selection is impaired, for example, the energy density cannot be maximized. There is room for improvement in this respect.
  • the capacity recovery method of the lithium ion battery described in Patent Document 1 is an appropriate method when the immobilization of lithium ions is the largest factor of the capacity reduction.
  • the capacity recovery operation cannot be performed even though there is originally a recoverable capacity.
  • the amount of lithium ions that should be replenished is calculated to be larger than the amount of lithium ions that should be replenished. Lithium metal precipitation may occur.
  • An object of the present invention is to recover a battery capacity reduced due to deterioration of a secondary battery due to immobilization of reaction species due to side reactions that occur in the secondary battery due to repeated charging and discharging.
  • the present invention is a method of recovering the capacity of a secondary battery having a positive electrode, a negative electrode, and a capacity recovery electrode as a third pole, and corresponds to a predetermined charging state from a charging curve or a discharging curve of the secondary battery.
  • the capacity recovery electrode and the positive electrode are set so that the absolute value of this difference becomes small.
  • it includes a capacity recovery step of moving the reaction type of the secondary battery to and from the negative electrode.
  • the present invention it is possible to recover the battery capacity reduced due to deterioration of the secondary battery due to immobilization of reaction species due to side reactions caused by repeated charging and discharging in the secondary battery.
  • an appropriate amount of reactive species can be replenished even for a battery using a single type of positive electrode active material.
  • FIG. 1 It is sectional drawing which conceptually shows the cell of the lithium ion battery which has a capacity recovery electrode. It is sectional drawing which conceptually shows the power generation element of the cell of FIG.
  • FIG. 1 It is sectional drawing which conceptually shows the cell of the lithium ion battery which has a capacity recovery electrode. It is sectional drawing which conceptually shows the power generation element of the cell of FIG.
  • FIG. 1 It is a graph for demonstrating the case where a plurality of extreme values in one voltage change rate curve are used as a feature quantity. It is a flow chart which shows the capacity recovery method of the lithium ion battery of Example 2. It is a graph which shows an example of the discharge curve of a lithium ion battery and the discharge curve of a positive electrode and a negative electrode obtained from this curve. It is a flow chart which shows the capacity recovery method of the lithium ion battery of Example 3.
  • FIG. It is a graph which shows the example which calculated
  • FIG. 1 is a cross-sectional view conceptually showing a cell of a lithium ion battery having a capacity recovery electrode.
  • the cell 100 includes an electrode portion 1, a positive electrode terminal 2, a negative electrode terminal 3, a capacitance recovery electrode terminal 4, a separator 5, and an exterior material 6.
  • the exterior material 6 is a laminated film or the like.
  • FIG. 2 is a cross-sectional view conceptually showing the power generation element of the cell of FIG.
  • the power generation element has a configuration in which the positive electrode 11 and the negative electrode 12 are alternately arranged with the separator 5 interposed therebetween.
  • the capacitance recovery electrode 15 is arranged on the outermost side as an electrode.
  • a separator 5 is also arranged outside the capacitance recovery electrode 15.
  • the positive electrode 11, the negative electrode 12, and the capacity recovery electrode 15 are each produced by applying a mixture of an appropriate electrode active material, a conductive agent, a binder, and the like to an appropriate metal current collector foil.
  • the active material of the capacity recovery electrode 15 contains a reactive species inside.
  • the reaction species of the lithium ion battery is lithium ion.
  • LiCoO 2 LiNi x Mn y Co z O 2 or the like is also used as a positive electrode active material as an active material of capacity recovery pole 15.
  • a metal tab is connected to the current collecting foils of the positive electrode 11, the negative electrode 12, and the capacity recovery electrode 15.
  • the exterior material 6 is sealed so that only the tab portion is exposed to the outside of the laminated film. As a result, the tabs become the positive electrode terminal 2, the negative electrode terminal 3, and the capacitance recovery electrode terminal 4 in FIG.
  • the power generation element is manufactured by facing the positive electrode 11 and the negative electrode 12 via the separator 5 and winding or laminating them.
  • the capacitance recovery pole 15 may be arranged near the winding shaft (central axis) of the wound body or at the outermost peripheral portion. Further, the capacity recovery electrode 15 may be arranged as a part of the laminated body.
  • FIG. 3 is a configuration diagram conceptually showing an example of a charging / discharging device connected to a battery pack having a capacity recovery electrode.
  • the battery pack 300 has a capacity recovery electrode in addition to the positive electrode and the negative electrode.
  • the charge / discharge device 350 includes an ammeter 351 (current sensor), a voltmeter 352 (voltage sensor), a resistor 353, a power supply 354, a control unit 355, a charge / discharge changeover switch 356, and a capacity recovery switch 357. including.
  • the battery pack 300 may include a plurality of cells. Further, the battery pack 300 may be configured to include a plurality of battery modules including a plurality of cells. As used herein, the term "secondary battery" is a concept that includes a cell, a battery module, or a battery pack of a lithium ion battery.
  • the positive and negative electrodes of the battery pack 300 and the terminals of the capacity recovery electrode are connected to the charging / discharging device 350.
  • the capacity recovery switch 357 is installed so as to connect either the negative electrode terminal or the capacity recovery electrode terminal of the battery pack 300 to the positive electrode terminal.
  • the present invention is not limited to the configuration shown in this figure, and the capacity recovery switch 357 may be installed so as to connect either the positive electrode terminal or the capacity recovery electrode terminal of the battery pack 300 to the negative electrode terminal. ..
  • the ammeter 351 measures the current flowing between the positive electrode and negative electrode terminals of the battery pack 300 or between the positive electrode and capacity recovery electrode terminals, and outputs the result to the control unit 355. Further, the voltmeter 352 measures the voltage between the positive electrode and the negative electrode, and outputs the result to the control unit 355. An additional voltmeter may be installed to measure the voltage between the positive electrode and the capacity recovery electrode or between the negative electrode and the capacity recovery electrode.
  • the control unit 355 calculates the charge / discharge curve data of the battery pack 300 based on the inputs from the ammeter 351 and the voltmeter 352. At this time, it is desirable that the voltage of the charge / discharge curve is a value close to the open circuit voltage.
  • the energization method when calculating the charge / discharge curve data is arbitrary.
  • a method of discharging from a fully charged state to a fully discharged state or a method of charging from a fully discharged state to a fully charged state with a minute and constant current is performed from the fully discharged state.
  • a method of repeating a cycle of discharging for a certain period of time with a constant current and then resting for a certain period of time from a fully charged state to a fully discharged state, or a cycle of charging for a certain period of time with a constant current and then resting for a certain period of time is performed from the fully discharged state.
  • There is a method of acquiring data on the relationship between the charge / discharge amount and the open circuit voltage by a method of repeating until a fully charged state.
  • the current waveform and voltage waveform during operation are statistically processed, or regression calculation processing (reproduction calculation processing) is performed based on the equivalent circuit to estimate the open circuit voltage, and the charge / discharge amount and open circuit voltage are There is also a way to estimate the relationship.
  • control unit 355 performs the following series of operations.
  • the feature amount of the obtained charge / discharge curve is extracted, and the charge / discharge amount from the capacity recovery electrode to the positive electrode is determined based on this. Further, a signal is output to the capacitance recovery switch 357 to connect the capacitance recovery electrode terminal and the positive electrode terminal. Further, a signal is output to the charge / discharge changeover switch 356, and the charge / discharge changeover switch 356 is operated according to the moving direction of the reaction species between the capacitance recovery electrode and the positive electrode. When the same material as the active material of the positive electrode is used as the active material of the capacity recovery electrode, when moving lithium ions from the capacity recovery electrode to the positive electrode, the charge / discharge changeover switch 356 is connected to the resistance side to recover the capacity from the positive electrode. Apply an electric current to the pole.
  • the charge / discharge changeover switch 356 is connected to the power supply side, and a current is passed from the capacity recovery electrode to the positive electrode.
  • the charge / discharge amount flowing between the positive electrode and the capacity recovery electrode is calculated based on the output of the ammeter, and when the target charge / discharge amount is reached, the capacity recovery switch 357 and the charge / discharge changeover switch 356 are operated. The current between the positive electrode and the capacity recovery electrode is cut off.
  • Examples 1 and 2 described below are methods for determining using the extreme value of
  • FIG. 4 is a graph showing an example of a discharge curve in an initial state and a deteriorated state of a lithium ion battery (hereinafter, also referred to as a “secondary battery”).
  • the horizontal axis represents the discharge amount, and the discharge amount 0 corresponds to the fully charged state.
  • the vertical axis is the battery voltage.
  • the broken line is the initial state, and the solid line is the deteriorated state. LiNi x Mn y Co z O 2 in the positive electrode, a negative electrode and using graphite.
  • the maximum value of the discharge amount is smaller than in the initial state. Further, in the deteriorated state, the voltage is slightly lowered.
  • the initial state is the time of the first discharge of an unused lithium ion battery after production or the time of discharge after using it several times (for example, once or more and less than 10 times) (repeating charging and discharging).
  • the deteriorated state is a state in which the performance of the battery is deteriorated by repeating charging and discharging 10 times or more from the initial state.
  • the performance comparison by repeating charging and discharging of the battery is not limited to the one from the initial state, and the discharge curve of the battery after being used an arbitrary number of times immediately after that and after being used 10 times or more. May be used.
  • FIG. 5 is a graph showing an example of the voltage change rate in the initial state and the deteriorated state of the lithium ion battery.
  • the horizontal axis is the discharge amount Q
  • the vertical axis is the rate of change of the battery voltage, that is, the absolute value of the derivative of the voltage V with respect to the discharge amount Q
  • the broken line is the initial state
  • the solid line is the deteriorated state.
  • the position of the extremum is different between the initial state and the deteriorated state. Position of the extreme value (maximum value), the amount of discharge in the initial state Q 0, and has a discharge amount Q 1 is in a degraded state. Q 1 is less than Q 0.
  • the position of this extreme value corresponds to a predetermined charging state of the negative electrode, that is, a state in which the density of lithium inserted in graphite is a predetermined value, as described in Non-Patent Document 1. Therefore, this change in the extreme value is due to a change in the correspondence between the charging state of the positive electrode and the negative electrode, such as isolation of the positive electrode active material, isolation of the negative electrode active material, and immobilization of lithium ions due to side reactions. It occurs as a cause.
  • the discharge curves in the initial state and the deteriorated state shown in this figure have the first peaks Q 0 and Q 1 that are clear when the discharge amount Q is small. Therefore, in this specification, the peak Q 0 in the initial state is referred to as "initial peak position".
  • the difference between the discharge amounts Q 0 and Q 1 may be regarded as the effect of the immobilization of lithium ions.
  • (Q 0- Q 1 ) can also be said to be "change from the initial peak position”.
  • the capacity recovery amount can be determined even when two types of positive electrode active materials are not used, that is, even when one type of positive electrode active material is used.
  • FIG. 6 shows a flow diagram of the capacity recovery method of the secondary battery of this embodiment.
  • (Q 0- Q 1 ) is compared with the threshold value (S150), and if (Q 0- Q 1 ) is equal to or greater than the threshold value, an operation of recovering the capacity of the secondary battery is performed (S160). If (Q 0- Q 1 ) is less than the threshold value, the operation of recovering the capacity of the secondary battery is not performed (S170).
  • step S130 If the extreme value is not clear in step S130, a reproduction calculation process is performed as shown in Example 3 described later, and an operation of recovering the capacity of the secondary battery is performed as necessary (S200).
  • the capacity recovery method of the secondary battery includes a step of calculating the absolute value
  • capacity recovery method for a secondary battery includes a step difference (Q 0 -Q 1) to determine whether more than a predetermined threshold value, if the difference (Q 0 -Q 1) is equal to or greater than the predetermined threshold value It is desirable to carry out a capacity recovery step.
  • the capacity recovery method of the secondary battery includes a step of calculating the absolute value
  • FIG. 7 is a graph for explaining a case where a plurality of extreme values in one voltage change rate curve are used as feature quantities.
  • the curve shown in this figure is the same as the curve shown in FIG.
  • the difference in the amount of discharge corresponding to the two extreme values (Q 0B ⁇ Q 0A ) and (Q 1B ⁇ Q 1A ) are indicators of the negative electrode capacity in the initial state and the deteriorated state, respectively. Comparing these two, for example, when the ratio (Q 1B- Q 1A ) / (Q 0B- Q 0A ) is less than 0.9, the capacity recovery is not performed, and when it is 0.9 or more (Q 0A- Q 1A ). Only recover capacity.
  • (Q 0B ⁇ Q 0A ) and (Q 1B ⁇ Q 1A ) can also be referred to as “distance between two peaks” or “distance between two extrema”.
  • the capacity of the battery can be recovered while avoiding the precipitation of lithium metal on the charging side.
  • FIG. 8 shows a flow diagram of the capacity recovery method of the secondary battery of this embodiment.
  • step S130 of FIG. 6 when there are two or more extreme values (peaks) of
  • the ratio (Q 1B ⁇ Q 1A ) / (Q 0B ⁇ Q 0A ) is calculated, and it is determined whether or not this ratio is equal to or greater than a predetermined value (S320).
  • the capacity recovery method of the secondary battery is as follows: the charge amount or discharge amount Q 0A and Q 0B , which are the positions of the two extreme values of
  • the charge amount or discharge amount Q 1A and Q 1B which are the positions of the two extreme values of
  • Q 0B- Q 0A ) and (Q 1B- Q 1A ) are used as indexes to determine the necessity of an operation for recovering the capacity of the secondary battery.
  • the charge / discharge curves of the battery should be analyzed to estimate the charge / discharge curves of the positive and negative electrodes, and the capacity recovery amount should be set so that the predetermined positive electrode potential and the predetermined negative electrode potential match. Is desirable.
  • FIG. 9 is a graph for conceptually explaining the discharge curves of the lithium ion battery, the positive electrode and the negative electrode, and the calculation method of the capacity recovery amount.
  • the discharge curve of the battery is a measured value calculated from the output values of the ammeter and the voltmeter, and the discharge curves of the positive electrode and the negative electrode are the calculated values obtained by the regression calculation process (reproduction calculation process).
  • the solid line is the discharge curve of the lithium-ion battery, the broken line is the discharge curve of the positive electrode, and the dotted line is the discharge curve of the negative electrode.
  • This figure was created using a discharge curve analysis that separates the discharge curve of the lithium-ion battery into the discharge curves of the positive electrode and the negative electrode.
  • the reproduction calculation process is performed as follows, for example, using the correction parameters m p , mn , C p , and C n .
  • the discharge curve per reference mass or reference area of the positive electrode and the negative electrode is recorded in the control unit 355 of the rechargeable device 350 shown in FIG. 3, after multiplying m p, a m n in the respective discharge amounts, C
  • the calculated values of the discharge curves of the positive electrode and the negative electrode are obtained by adding p and C n for correction.
  • the calculated value of the discharge curve of the battery can be obtained by obtaining the difference between the positive electrode potential and the negative electrode potential corresponding to the same discharge amount.
  • the correction parameters m p , mn , C p , and C n of the positive electrode and negative electrode capacities are adjusted so that the calculated value of the discharge curve of the battery matches the measured value.
  • the discharge amount corresponding to the predetermined charging state is calculated.
  • the discharge amount corresponding to each of the positive electrode potential and the negative electrode potential corresponding to a predetermined charging state is calculated.
  • V p0 corresponding to the predetermined positive electrode potential V p0 as shown in FIG. 9 is obtained. Further, the discharge amount Q n0 corresponding to the predetermined negative electrode potential V n0 is obtained. Then, an amount of lithium ions corresponding to the difference between the two (Q p0 ⁇ Q n0 ) is moved from the capacity recovery electrode to the positive electrode.
  • V p0 and V n0 are potentials of the positive electrode and the negative electrode corresponding to a predetermined charging state (same charging state) of the battery.
  • the negative electrode potential becomes V n0 when the positive electrode potential is V p0 .
  • V n0 is set to, for example, 0.8 V and set at a position where the negative electrode potential rises rapidly, the negative electrode potential at the end of battery discharge becomes a value close to V n0 , and therefore the positive electrode potential becomes V p0. .. That is, when the battery is discharged, the open circuit potential of the positive electrode does not become V p0 or less, and over-discharging of the positive electrode can be avoided. As a result, deterioration of the battery after capacity recovery can be suppressed.
  • FIG. 10 summarizes the capacity recovery method of the secondary battery of this embodiment as a flow chart.
  • step S130 if the extreme value is not clear (S130), the process proceeds to step S200.
  • the charge curve or discharge curve of FIG. 10 is separated into the charge curve or discharge curve of the positive electrode and the negative electrode (S410: positive electrode / negative electrode separation step).
  • the capacitance corresponding to a predetermined potential is extracted for each of the positive electrode and the negative electrode (S420).
  • the difference in capacitance between the positive electrode and the negative electrode (Q p0 ⁇ Q n0 ) is calculated (S430), and it is determined whether or not the difference is equal to or greater than the threshold value (S440).
  • Q n0 and Q 1 are indices derived from the negative electrode, Q 1 corresponding to the above-mentioned extreme value of the voltage change rate can be used instead of Q n 0.
  • the capacity recovery method of the secondary battery includes a positive electrode / negative electrode separation step of separating the charge curve or discharge curve of the secondary battery into a charge curve or discharge curve of the positive electrode and the negative electrode, and a charge curve or discharge curve of the positive electrode and the negative electrode, respectively.
  • comprises the step of determining whether more than a predetermined threshold value, the absolute value of the difference
  • step S200 when the extreme value is not clear in FIG. 6 (S130), but the method of this embodiment is not limited to this. Instead, the reproduction calculation process of the step S410 of FIG. 10 may be performed from the beginning, and the processes after the step S420 may be performed without discriminating the extreme value.
  • is calculated from the charge curve or the discharge curve of each of the positive electrode and the negative electrode, and the extreme value of
  • the processing after the step S310 of FIG. 8 may be performed.
  • FIG. 11 is a graph showing an example in which the absolute value
  • the horizontal axis is the discharge amount q per mass of the positive electrode active material, and the vertical axis is the rate of change in the potential of the positive electrode, that is, the absolute value of the derivative of the voltage V with respect to the discharge amount q
  • FIG. 12 is a graph showing an example in which the absolute value
  • the horizontal axis is the discharge amount q per mass of the negative electrode active material, and the vertical axis is the rate of change of the potential of the negative electrode, that is, the absolute value of the derivative of the voltage V with respect to the discharge amount q
  • the capacity recovery electrode and the positive electrode or the negative electrode are set so that the absolute value of this difference becomes small. It includes a capacity recovery step of moving the reactive species of the secondary battery between.
  • the positive electrode, the negative electrode and the capacity recovery electrode are built-in and sealed, but the present invention can be applied to the unsealed cell.
  • the positive electrode and the negative electrode are wound or laminated and installed in a container, and the electrolytic solution is injected into the container and charged / discharged without sealing.
  • the container may be a battery container before sealing the product, but may be another container for immersing the positive electrode, the negative electrode, and the capacity recovery electrode in the electrolytic solution.
  • a deviation in the amount of discharge between the positive electrode and the negative electrode occurs due to a side reaction that forms a film on the surface of the negative electrode.
  • the capacitance recovery electrode is temporarily introduced into the container, and lithium ions are transferred between the capacitance recovery electrode and the positive electrode or the negative electrode by any of the above methods. Then, after removing the capacity recovery electrode, the cell is sealed.
  • the capacity reduction of the cell generated in the initial stage can be compensated by the capacity recovery process, and the occurrence of additional side reactions can be suppressed, so that the bipolar cell similar to the conventional lithium ion battery has a long life. Can be transformed into.
  • the present embodiment relates to a method for manufacturing a lithium ion battery (secondary battery).
  • the capacity recovery pole may be rephrased as a "capacity adjustment pole”.
  • the method for manufacturing the secondary battery is a step of installing the positive electrode and the negative electrode of the secondary battery in a state where they can be charged and discharged, and a capacity adjusting electrode as the third electrode between at least one of the positive electrode and the negative electrode.
  • the process of installing the reaction type of the secondary battery so that it can be moved, the process of acquiring the charge curve or discharge curve of the secondary battery, and the charge curve or discharge curve of the secondary battery are the charge curves of the positive electrode and the negative electrode.
  • the positive electrode / negative electrode separation step of separating into a discharge curve and the charge curve or discharge curve of the positive electrode and the negative electrode, respectively the capacities Q p0 and Q n0 corresponding to the predetermined potentials V p0 and V n0 for the positive electrode and the negative electrode, respectively.
  • comprises the step of determining whether more than a predetermined threshold value, the absolute value of the difference
  • Electrode part 2 Positive terminal 3: Negative electrode terminal 4: Capacity recovery electrode terminal 5: Separator, 6: Exterior material, 11: Positive electrode, 12: Negative electrode, 15: Capacity recovery electrode, 100: Cell, 300 : Battery pack, 350: Charge / discharge device, 351: Current meter, 352: Voltage meter, 353: Resistance, 354: Power supply, 355: Control unit, 356: Charge / discharge changeover switch, 357: Capacity recovery switch.

Abstract

Provided is a method for recovering the capacity of a secondary battery (a capacity recovering method for a secondary battery) having a positive electrode, a negative electrode, and a capacity recovery electrode as a third pole, the method comprising: a step for calculating two or more discharge amounts corresponding to a predetermined charge state, from the charge curve or discharge curve of the secondary battery; and a capacity recovery step for using, as an index, a difference between two predetermined discharge amounts among the two or more discharge amounts to move reaction species of the secondary battery between the capacity recovery electrode and the positive electrode or negative electrode such that the absolute value of the difference becomes small. Thus, it is possible to recover the battery capacity reduced by the deterioration of the secondary battery due to immobilization of the reaction species caused by side reactions that occur with repeated charging and discharging in the secondary battery.

Description

二次電池の容量回復方法及び製造方法Secondary battery capacity recovery method and manufacturing method
　本発明は、二次電池の容量回復方法及び製造方法に関する。 The present invention relates to a method for recovering the capacity of a secondary battery and a method for manufacturing the secondary battery.
　リチウムイオン電池は、非水電解質二次電池の一つであり、エネルギー密度が高いため、携帯機器のバッテリーや、近年では電気自動車のバッテリーとしても用いられている。
ただし、リチウムイオン電池は、使用に伴い劣化し、電池容量が減少することが知られている。 Lithium-ion batteries are one of the non-aqueous electrolyte secondary batteries, and because of their high energy density, they are also used as batteries for portable devices and, in recent years, as batteries for electric vehicles.
However, it is known that a lithium ion battery deteriorates with use and the battery capacity decreases.
　リチウムイオン電池では、正極の活物質としてリチウム金属酸化物、負極の活物質とし黒鉛などの炭素材が用いられるのが一般的である。リチウムイオン電池の正極および負極は、微小な活物質粒子群にバインダや導電剤等を加えてスラリー化した後、金属箔に塗布して形成する。 In a lithium ion battery, a lithium metal oxide is generally used as the active material for the positive electrode, and a carbon material such as graphite is generally used as the active material for the negative electrode. The positive electrode and the negative electrode of the lithium ion battery are formed by adding a binder, a conductive agent, or the like to a group of minute active material particles to form a slurry, and then applying the mixture to a metal foil.
　充電時には正極の活物質から放出されたリチウムイオンが負極の活物質に吸蔵され、放電時には負極の活物質に吸蔵されたリチウムイオンが放出され正極の活物質に吸蔵される。このように、リチウムイオンが電極間を移動することで電極間に電流が流れる。このようなリチウムイオン電池では、（１）正極活物質の電気的な孤立、（２）負極活物質の電気的な孤立、及び（３）電極間を往来するリチウムイオンの固定化によって容量が減少する。 At the time of charging, the lithium ions released from the active material of the positive electrode are occluded in the active material of the negative electrode, and at the time of discharging, the lithium ions stored in the active material of the negative electrode are occluded and stored in the active material of the positive electrode. In this way, the lithium ions move between the electrodes, causing a current to flow between the electrodes. In such a lithium ion battery, the capacity is reduced by (1) electrical isolation of the positive electrode active material, (2) electrical isolation of the negative electrode active material, and (3) immobilization of lithium ions moving back and forth between the electrodes. To do.
　これらの要因のうち、上記（３）による容量減少分については、内部にリチウムを含む第３の電極を備えたリチウムイオン電池を作製し、第３の電極から正極または負極にリチウムイオンを補充することによって容量減少分を回復させることが可能である。 Of these factors, for the capacity reduction due to (3) above, a lithium ion battery having a third electrode containing lithium inside is manufactured, and lithium ions are replenished from the third electrode to the positive electrode or the negative electrode. By doing so, it is possible to recover the reduced capacity.
　しかしながら、リチウムイオンを過剰に補充してしまうと、充電時に負極活物質に吸蔵しきれないリチウムイオンがリチウム金属として析出したり、放電時に正極活物質中のリチウムイオン濃度が過剰になって電池の特性劣化を助長したりする問題が生じる。このような場合には、リチウムイオン電池が不安全化したり、容量回復が不十分になったりするおそれがある。 However, if the lithium ions are excessively replenished, lithium ions that cannot be completely occluded in the negative electrode active material during charging will be deposited as lithium metal, or the lithium ion concentration in the positive electrode active material will be excessive during discharge, resulting in an excessive amount of lithium ions in the battery. Problems such as promoting deterioration of characteristics occur. In such a case, the lithium ion battery may become unsafe or the capacity recovery may be insufficient.
　特許文献１には、リチウムデンドライトの形成を抑制した適切な量のリチウムイオンを補充して、リチウムイオン電池の容量を回復させることを課題として、第１活物質及び該第１活物質よりも電極電位が卑である第２活物質を含む正極と、負極と、電解質液と、リチウムイオンを放出するリチウムイオン補充用電極（第３電極）と、を備えたリチウムイオン電池の容量を回復させる方法であって、充放電時の電圧が第１活物質に対応する電極電位を保持する領域である第１プラトー領域と、充放電時の電圧が第２活物質に対応する電極電位を保持する領域である第２プラトー領域との長さに基づき、所定の場合には劣化原因がリチウムイオンの減少であると判定し、第３電極からのリチウムイオンを適量供給するものが開示されている。 Patent Document 1 describes the first active material and an electrode rather than the first active material, with an object of replenishing an appropriate amount of lithium ions that suppress the formation of lithium dendrite to recover the capacity of the lithium ion battery. A method for recovering the capacity of a lithium ion battery including a positive electrode containing a second active material having a low potential, a negative electrode, an electrolyte solution, and a lithium ion replenishment electrode (third electrode) that emits lithium ions. The first plateau region, which is a region where the charge / discharge voltage holds the electrode potential corresponding to the first active material, and the region where the charge / discharge voltage holds the electrode potential corresponding to the second active material. Based on the length with the second plateau region, it is determined that the cause of deterioration is a decrease in lithium ions in a predetermined case, and an appropriate amount of lithium ions from the third electrode is disclosed.
　特許文献２には、非破壊で、かつ簡便な方法で、二次電池の内部における正極の状況と負極の状況とを検知するために、補正パラメータとして、正極有効活物質量mpと、負極有効活物質量mnと、正極の放電カーブの位置関係の指標Cpと、負極の放電カーブの位置関係の指標Cnとを用いて、微小な電流で二次電池の充放電を行った場合に得られた二次電池の充放電カーブを、別途測定した正極単独および負極単独の充放電カーブの重ね合わせ計算を行うことで再現する方法が開示されている。 In Patent Document 2, in order to detect the status of the positive electrode and the status of the negative electrode inside the secondary battery by a non-destructive and simple method, the positive electrode effective active material amount m p and the negative electrode are as correction parameters. The secondary battery was charged and discharged with a minute current using the amount of effective active material m n , the index C p of the positional relationship of the discharge curve of the positive electrode, and the index C n of the positional relationship of the discharge curve of the negative electrode. A method of reproducing the charge / discharge curve of the secondary battery obtained in the case by superimposing the charge / discharge curves of the positive electrode alone and the negative electrode alone measured separately is disclosed.
　非特許文献１においては、放電曲線を正電極及び負電極の放電曲線に分離する放電曲線解析を用いた充電／放電サイクルにおけるＬｉＣｏＯ２／グラファイトセルの劣化メカニズムとして、初期状態から充放電サイクルを繰り返した場合において放電量Ｑによる電圧Ｖの導関数の絶対値｜ｄＶ／ｄＱ｜の極大値の変化や、セル、正極及び負極についての初期値からの容量の変化、並びに不可逆的なリチウムイオン損失等が検討されている。非特許文献１には、電池の｜ｄＶ／ｄＱ｜の極大値が、分離された正電極又は負電極の｜ｄＶ／ｄＱ｜の極大値のいずれかに一致することが記載されている。 In Non-Patent Document 1, the charge / discharge cycle is repeated from the initial state as a deterioration mechanism of the LiCoO 2 / graphite cell in the charge / discharge cycle using the discharge curve analysis that separates the discharge curve into the discharge curves of the positive electrode and the negative electrode. In this case, the change in the maximum value of the derivative of the voltage V due to the discharge amount Q | dV / dQ |, the change in capacitance from the initial value for the cell, positive electrode and negative electrode, and the irreversible lithium ion loss, etc. Is being considered. Non-Patent Document 1 describes that the maximum value of | dV / dQ | of the battery matches either the maximum value of | dV / dQ | of the separated positive electrode or negative electrode.
　非特許文献２には、高出力リチウムイオン電池のＶ－Ｑ曲線について、導関数ｄＶ／ｄＱ曲線の極値を用いて分析する方法が記載されている。 Non-Patent Document 2 describes a method of analyzing the VQ curve of a high-power lithium-ion battery using the extreme value of the derivative dV / dQ curve.
国際公開第２０１２／１２４２１１号International Publication No. 2012/124211 特許第４８８４４０４号公報Japanese Patent No. 4884404
　特許文献１に記載のリチウムイオン電池の容量回復方法は、反応電位の異なる２種類の正極活物質を用いる場合に関するものであり、材料選定の自由度が損なわれ、例えばエネルギー密度を最大化できないなどの点で改善の余地がある。 The capacity recovery method of the lithium ion battery described in Patent Document 1 relates to a case where two types of positive electrode active materials having different reaction potentials are used, and the degree of freedom in material selection is impaired, for example, the energy density cannot be maximized. There is room for improvement in this respect.
　また、特許文献１に記載のリチウムイオン電池の容量回復方法は、リチウムイオンの固定化が容量減少の最大の要因である場合には適切な方法となる。しかしながら、正極活物質の電気的な孤立とリチウムイオンの固定化とが同程度に発生している場合には、本来は回復可能な容量が存在するにもかかわらず容量回復操作ができない。また、負極活物質の電気的な孤立とリチウムイオンの固定化とが同程度に発生している場合には、本来補充すべきリチウムイオンの量よりも大きな量を算出してしまい、充電時のリチウム金属析出を発生させるおそれがある。 Further, the capacity recovery method of the lithium ion battery described in Patent Document 1 is an appropriate method when the immobilization of lithium ions is the largest factor of the capacity reduction. However, when the electrical isolation of the positive electrode active material and the immobilization of lithium ions occur to the same extent, the capacity recovery operation cannot be performed even though there is originally a recoverable capacity. In addition, when the electrical isolation of the negative electrode active material and the immobilization of lithium ions occur to the same extent, the amount of lithium ions that should be replenished is calculated to be larger than the amount of lithium ions that should be replenished. Lithium metal precipitation may occur.
　本発明は、二次電池において充電及び放電の繰り返しに伴って生じる副反応による反応種の固定化等を原因とする二次電池の劣化により減少した電池容量を回復することを目的とする。 An object of the present invention is to recover a battery capacity reduced due to deterioration of a secondary battery due to immobilization of reaction species due to side reactions that occur in the secondary battery due to repeated charging and discharging.
　本発明は、正極、負極、及び第三極としての容量回復極を有する二次電池の容量を回復する方法であって、二次電池の充電曲線又は放電曲線から、所定の充電状態に対応する２つ以上の放電量を算出する工程と、前記２つ以上の放電量のうちの所定の２つの放電量の差を指標とし、この差の絶対値が小さくなるように、容量回復極と正極又は負極との間で二次電池の反応種を移動させる容量回復工程と、を含む。 The present invention is a method of recovering the capacity of a secondary battery having a positive electrode, a negative electrode, and a capacity recovery electrode as a third pole, and corresponds to a predetermined charging state from a charging curve or a discharging curve of the secondary battery. Using the difference between the step of calculating two or more discharge amounts and the predetermined two discharge amounts of the two or more discharge amounts as an index, the capacity recovery electrode and the positive electrode are set so that the absolute value of this difference becomes small. Alternatively, it includes a capacity recovery step of moving the reaction type of the secondary battery to and from the negative electrode.
　本発明によれば、二次電池において充電及び放電の繰り返しに伴って生じる副反応による反応種の固定化等を原因とする二次電池の劣化により減少した電池容量を回復することができる。また、単一種類の正極活物質を使用する電池に対しても、適切な量の反応種を補充することができる。 According to the present invention, it is possible to recover the battery capacity reduced due to deterioration of the secondary battery due to immobilization of reaction species due to side reactions caused by repeated charging and discharging in the secondary battery. In addition, an appropriate amount of reactive species can be replenished even for a battery using a single type of positive electrode active material.
容量回復極を有するリチウムイオン電池のセルを概念的に示す断面図である。It is sectional drawing which conceptually shows the cell of the lithium ion battery which has a capacity recovery electrode. 図１のセルの発電要素を概念的に示す断面図である。It is sectional drawing which conceptually shows the power generation element of the cell of FIG. 容量回復極を有する電池パックに接続された充放電装置の一例を示す概略構成図である。It is a schematic block diagram which shows an example of the charge / discharge device connected to the battery pack which has a capacity recovery electrode. リチウムイオン電池の初期状態及び劣化状態の放電曲線の一例を示すグラフである。It is a graph which shows an example of the discharge curve of the initial state and the deteriorated state of a lithium ion battery. リチウムイオン電池の初期状態及び劣化状態の電圧変化率の一例を示すグラフである。It is a graph which shows an example of the voltage change rate of the initial state and the deteriorated state of a lithium ion battery. 実施例１のリチウムイオン電池の容量回復方法を示すフロー図である。It is a flow chart which shows the capacity recovery method of the lithium ion battery of Example 1. FIG. １つの電圧変化率の曲線における複数の極値を特徴量として使用する場合について説明するためのグラフである。It is a graph for demonstrating the case where a plurality of extreme values in one voltage change rate curve are used as a feature quantity. 実施例２のリチウムイオン電池の容量回復方法を示すフロー図である。It is a flow chart which shows the capacity recovery method of the lithium ion battery of Example 2. リチウムイオン電池の放電曲線並びにこの曲線から得られた正極及び負極の放電曲線の一例を示すグラフである。It is a graph which shows an example of the discharge curve of a lithium ion battery and the discharge curve of a positive electrode and a negative electrode obtained from this curve. 実施例３のリチウムイオン電池の容量回復方法を示すフロー図である。It is a flow chart which shows the capacity recovery method of the lithium ion battery of Example 3. FIG. 再現計算処理の後、正極の放電曲線から｜ｄＶ／ｄｑ｜を算出した例を示すグラフである。It is a graph which shows the example which calculated | dV / dq | from the discharge curve of the positive electrode after the reproduction calculation process. 再現計算処理の後、負極の放電曲線から｜ｄＶ／ｄｑ｜を算出した例を示すグラフである。It is a graph which shows the example which calculated | dV / dq | from the discharge curve of the negative electrode after the reproduction calculation process.
　以下、図面を参照して本発明の実施形態について説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　図１は、容量回復極を有するリチウムイオン電池のセルを概念的に示す断面図である。 FIG. 1 is a cross-sectional view conceptually showing a cell of a lithium ion battery having a capacity recovery electrode.
　本図において、セル１００は、電極部分１と、正極端子２と、負極端子３と、容量回復極端子４と、セパレータ５と、外装材６と、を備えている。外装材６は、ラミネートフィルム等である。 In this figure, the cell 100 includes an electrode portion 1, a positive electrode terminal 2, a negative electrode terminal 3, a capacitance recovery electrode terminal 4, a separator 5, and an exterior material 6. The exterior material 6 is a laminated film or the like.
　図２は、図１のセルの発電要素を概念的に示す断面図である。 FIG. 2 is a cross-sectional view conceptually showing the power generation element of the cell of FIG.
　図２において、発電要素は、正極１１と負極１２とがセパレータ５を挟んで交互に配置された構成を有する。容量回復極１５は、電極としては最も外側に配置されている。容量回復極１５の外側にも、セパレータ５が配置されている。 In FIG. 2, the power generation element has a configuration in which the positive electrode 11 and the negative electrode 12 are alternately arranged with the separator 5 interposed therebetween. The capacitance recovery electrode 15 is arranged on the outermost side as an electrode. A separator 5 is also arranged outside the capacitance recovery electrode 15.
　正極１１、負極１２及び容量回復極１５は、それぞれ、適切な金属の集電箔に適切な電極活物質、導電剤、結着剤等の混合体を塗布して作製されたものである。 The positive electrode 11, the negative electrode 12, and the capacity recovery electrode 15 are each produced by applying a mixture of an appropriate electrode active material, a conductive agent, a binder, and the like to an appropriate metal current collector foil.
　容量回復極１５の活物質は、反応種を内部に含むものが望ましい。リチウムイオン電池の反応種は、リチウムイオンである。この場合、例えば、正極活物質としても用いられるＬｉＣｏＯ２、ＬｉＮｉｘＭｎｙＣｏｚＯ２等を容量回復極１５の活物質として用いることができる。 It is desirable that the active material of the capacity recovery electrode 15 contains a reactive species inside. The reaction species of the lithium ion battery is lithium ion. In this case, for example, can be used LiCoO 2, LiNi x Mn y Co z O 2 or the like is also used as a positive electrode active material as an active material of capacity recovery pole 15.
　正極１１、負極１２及び容量回復極１５の集電箔には、金属のタブが接続されている。
タブ部分だけがラミネートフィルムの外部に露出するように外装材６を封止する。これにより、タブが図１の正極端子２、負極端子３及び容量回復極端子４となる。 A metal tab is connected to the current collecting foils of the positive electrode 11, the negative electrode 12, and the capacity recovery electrode 15.
The exterior material 6 is sealed so that only the tab portion is exposed to the outside of the laminated film. As a result, the tabs become the positive electrode terminal 2, the negative electrode terminal 3, and the capacitance recovery electrode terminal 4 in FIG.
　発電要素は、正極１１と負極１２とをセパレータ５を介して対向させ、捲回あるいは積層をすることにより作製する。容量回復極１５は、捲回体の捲回軸（中心軸）付近または最外周部に配置してもよい。また、容量回復極１５は、積層体の一部として配置してもよい。 The power generation element is manufactured by facing the positive electrode 11 and the negative electrode 12 via the separator 5 and winding or laminating them. The capacitance recovery pole 15 may be arranged near the winding shaft (central axis) of the wound body or at the outermost peripheral portion. Further, the capacity recovery electrode 15 may be arranged as a part of the laminated body.
　図３は、容量回復極を有する電池パックに接続された充放電装置の一例を概念的に示す構成図である。 FIG. 3 is a configuration diagram conceptually showing an example of a charging / discharging device connected to a battery pack having a capacity recovery electrode.
　本図において、電池パック３００は、正極及び負極に加え、容量回復極を有する。充放電装置３５０は、電流計３５１（電流センサ）と、電圧計３５２（電圧センサ）と、抵抗３５３と、電源３５４と、制御部３５５と、充放電切り替えスイッチ３５６と、容量回復スイッチ３５７と、を含む。 In this figure, the battery pack 300 has a capacity recovery electrode in addition to the positive electrode and the negative electrode. The charge / discharge device 350 includes an ammeter 351 (current sensor), a voltmeter 352 (voltage sensor), a resistor 353, a power supply 354, a control unit 355, a charge / discharge changeover switch 356, and a capacity recovery switch 357. including.
　電池パック３００は、複数個のセルを含むものであってもよい。また、電池パック３００は、複数個のセルを含む電池モジュールを複数個含む構成であってもよい。本明細書において、「二次電池」は、リチウムイオン電池のセル、電池モジュール又は電池パックを含む概念である。 The battery pack 300 may include a plurality of cells. Further, the battery pack 300 may be configured to include a plurality of battery modules including a plurality of cells. As used herein, the term "secondary battery" is a concept that includes a cell, a battery module, or a battery pack of a lithium ion battery.
　電池パック３００の正極、負極及び容量回復極の端子は、充放電装置３５０に接続されている。 The positive and negative electrodes of the battery pack 300 and the terminals of the capacity recovery electrode are connected to the charging / discharging device 350.
　容量回復スイッチ３５７は、電池パック３００の負極端子及び容量回復極端子のいずれかを正極端子と接続するように設置している。なお、本発明は、本図の構成に限定されるものではなく、電池パック３００の正極端子及び容量回復極端子のいずれかを負極端子と接続するように容量回復スイッチ３５７を設置してもよい。 The capacity recovery switch 357 is installed so as to connect either the negative electrode terminal or the capacity recovery electrode terminal of the battery pack 300 to the positive electrode terminal. The present invention is not limited to the configuration shown in this figure, and the capacity recovery switch 357 may be installed so as to connect either the positive electrode terminal or the capacity recovery electrode terminal of the battery pack 300 to the negative electrode terminal. ..
　電流計３５１は、電池パック３００の正極・負極端子間または正極・容量回復極端子間に流れる電流を測定し、結果を制御部３５５に出力する。また、電圧計３５２は、正極・負極間の電圧を測定し、結果を制御部３５５に出力する。なお、正極・容量回復極間や負極・容量回復極間の電圧を測定するための電圧計を追加で設置してもよい。 The ammeter 351 measures the current flowing between the positive electrode and negative electrode terminals of the battery pack 300 or between the positive electrode and capacity recovery electrode terminals, and outputs the result to the control unit 355. Further, the voltmeter 352 measures the voltage between the positive electrode and the negative electrode, and outputs the result to the control unit 355. An additional voltmeter may be installed to measure the voltage between the positive electrode and the capacity recovery electrode or between the negative electrode and the capacity recovery electrode.
　制御部３５５は、電流計３５１および電圧計３５２からの入力を元に、電池パック３００の充放電曲線のデータを算出する。この際、充放電曲線の電圧は、開回路電圧に近い値であることが望ましい。充放電曲線のデータを算出する際における通電方法は任意である。 The control unit 355 calculates the charge / discharge curve data of the battery pack 300 based on the inputs from the ammeter 351 and the voltmeter 352. At this time, it is desirable that the voltage of the charge / discharge curve is a value close to the open circuit voltage. The energization method when calculating the charge / discharge curve data is arbitrary.
　例えば、微小かつ一定の電流で、満充電状態から全放電状態まで放電する方法、もしくは全放電状態から満充電状態まで充電する方法がある。また、一定の電流で一定時間放電した後、一定時間休止するサイクルを満充電状態から全放電状態まで繰り返す方法、もしくは一定の電流で一定時間充電した後、一定時間休止するサイクルを全放電状態から満充電状態まで繰り返す方法により、充放電量と開回路電圧との関係についてのデータを取得する方法がある。また、運転中の電流波形および電圧波形を統計的に処理し、もしくは等価回路に基づき回帰計算処理（再現計算処理）をして、開回路電圧を推定し、充放電量と開回路電圧との関係を推定する方法もある。 For example, there is a method of discharging from a fully charged state to a fully discharged state or a method of charging from a fully discharged state to a fully charged state with a minute and constant current. In addition, a method of repeating a cycle of discharging for a certain period of time with a constant current and then resting for a certain period of time from a fully charged state to a fully discharged state, or a cycle of charging for a certain period of time with a constant current and then resting for a certain period of time is performed from the fully discharged state. There is a method of acquiring data on the relationship between the charge / discharge amount and the open circuit voltage by a method of repeating until a fully charged state. In addition, the current waveform and voltage waveform during operation are statistically processed, or regression calculation processing (reproduction calculation processing) is performed based on the equivalent circuit to estimate the open circuit voltage, and the charge / discharge amount and open circuit voltage are There is also a way to estimate the relationship.
　なお、上述の充放電曲線のデータを算出する際における通電方法に関して、「満充電状態から全放電状態まで放電」及び「満充電状態から全放電状態まで充電」と記載したが、通電方法は、必ずしもこれらの範囲で放電又は充電するものに限定されるものではない。
充放電の範囲は、広いほうが望ましく、１００％の範囲で充放電するのが最も望ましいが、その後の工程が円滑に行えるならば、満充電状態から全放電状態までの５０％以上の範囲で充放電してもよい。さらに、可能であれば、５０％未満の範囲でもよい。 Regarding the energizing method when calculating the above-mentioned charge / discharge curve data, "discharging from a fully charged state to a fully discharged state" and "charging from a fully charged state to a fully discharged state" have been described. It is not necessarily limited to those that discharge or charge within these ranges.
The range of charge / discharge is preferably wide, and it is most desirable to charge / discharge in the range of 100%, but if the subsequent process can be performed smoothly, it is charged in the range of 50% or more from the fully charged state to the fully discharged state. It may be discharged. Further, if possible, the range may be less than 50%.
　さらに、制御部３５５は、次に示す一連の操作を行う。 Further, the control unit 355 performs the following series of operations.
　得られた充放電曲線の特徴量を抽出し、これに基づいて容量回復極から正極への充放電量を決定する。また、容量回復スイッチ３５７に信号を出力し、容量回復極端子と正極端子とを接続する。また、充放電切り替えスイッチ３５６に信号を出力し、容量回復極と正極との間の反応種の移動方向に応じて、充放電切り替えスイッチ３５６を操作する。容量回復極の活物質として正極の活物質と同じ材料を用いる場合には、容量回復極から正極にリチウムイオンを移動させる場合には、充放電切り替えスイッチ３５６を抵抗側に繋ぎ、正極から容量回復極に電流を流す。逆に、正極から容量回復極にリチウムイオンを移動させる場合には、充放電切り替えスイッチ３５６を電源側に繋ぎ、容量回復極から正極に電流を流す。この際、電流計の出力に基づき、正極と容量回復極との間に流れた充放電量を算出し、目標とする充放電量に到達したら容量回復スイッチ３５７及び充放電切り替えスイッチ３５６を操作して、正極と容量回復極との間の電流を遮断する。 The feature amount of the obtained charge / discharge curve is extracted, and the charge / discharge amount from the capacity recovery electrode to the positive electrode is determined based on this. Further, a signal is output to the capacitance recovery switch 357 to connect the capacitance recovery electrode terminal and the positive electrode terminal. Further, a signal is output to the charge / discharge changeover switch 356, and the charge / discharge changeover switch 356 is operated according to the moving direction of the reaction species between the capacitance recovery electrode and the positive electrode. When the same material as the active material of the positive electrode is used as the active material of the capacity recovery electrode, when moving lithium ions from the capacity recovery electrode to the positive electrode, the charge / discharge changeover switch 356 is connected to the resistance side to recover the capacity from the positive electrode. Apply an electric current to the pole. On the contrary, when moving the lithium ion from the positive electrode to the capacity recovery electrode, the charge / discharge changeover switch 356 is connected to the power supply side, and a current is passed from the capacity recovery electrode to the positive electrode. At this time, the charge / discharge amount flowing between the positive electrode and the capacity recovery electrode is calculated based on the output of the ammeter, and when the target charge / discharge amount is reached, the capacity recovery switch 357 and the charge / discharge changeover switch 356 are operated. The current between the positive electrode and the capacity recovery electrode is cut off.
　次に説明する実施例１及び２は、二次電池の｜ｄＶ／ｄＱ｜の極値を用いて判定する方法である。 Examples 1 and 2 described below are methods for determining using the extreme value of | dV / dQ | of the secondary battery.
　図４は、リチウムイオン電池（以下「二次電池」ともいう。）の初期状態及び劣化状態の放電曲線の一例を示すグラフである。横軸は放電量であり、放電量０は満充電状態に対応する。縦軸は電池電圧である。破線が初期状態であり、実線が劣化状態である。正極にはＬｉＮｉｘＭｎｙＣｏｚＯ２、負極には黒鉛を用いている。 FIG. 4 is a graph showing an example of a discharge curve in an initial state and a deteriorated state of a lithium ion battery (hereinafter, also referred to as a “secondary battery”). The horizontal axis represents the discharge amount, and the discharge amount 0 corresponds to the fully charged state. The vertical axis is the battery voltage. The broken line is the initial state, and the solid line is the deteriorated state. LiNi x Mn y Co z O 2 in the positive electrode, a negative electrode and using graphite.
　本図に示すように、劣化状態においては、初期状態に比べ、放電量の最大値が小さくなっている。また、劣化状態においては、電圧が若干低下している。 As shown in this figure, in the deteriorated state, the maximum value of the discharge amount is smaller than in the initial state. Further, in the deteriorated state, the voltage is slightly lowered.
　ここで、初期状態とは、製造後未使用のリチウムイオン電池の１回目の放電時又は数回（例えば１回以上１０回未満）の使用（充電及び放電の繰り返し）をした後の放電時における電池の状態をいう。また、劣化状態とは、初期状態から例えば１０回以上の充電及び放電の繰り返しを行い、電池の性能が低下した状態をいう。 Here, the initial state is the time of the first discharge of an unused lithium ion battery after production or the time of discharge after using it several times (for example, once or more and less than 10 times) (repeating charging and discharging). The state of the battery. The deteriorated state is a state in which the performance of the battery is deteriorated by repeating charging and discharging 10 times or more from the initial state.
　なお、電池の充電及び放電の繰り返しによる性能比較は、初期状態からのものに限定されるものではなく、任意の回数使用した後の電池について、その直後及び更に１０回以上使用した後における放電曲線を用いてもよい。 The performance comparison by repeating charging and discharging of the battery is not limited to the one from the initial state, and the discharge curve of the battery after being used an arbitrary number of times immediately after that and after being used 10 times or more. May be used.
　負極の所定の充電状態に対応する電池の充電量又は放電量を簡便に判定する手段としては、リチウムイオン電池の電圧変化率の極値を判定する方法がある。 As a means for easily determining the charge amount or discharge amount of the battery corresponding to the predetermined charge state of the negative electrode, there is a method of determining the extreme value of the voltage change rate of the lithium ion battery.
　図５は、リチウムイオン電池の初期状態及び劣化状態の電圧変化率の一例を示すグラフである。横軸は放電量Ｑであり、縦軸は電池電圧の変化率すなわち放電量Ｑに対する電圧Ｖの導関数の絶対値｜ｄＶ／ｄＱ｜である。破線が初期状態であり、実線が劣化状態である。 FIG. 5 is a graph showing an example of the voltage change rate in the initial state and the deteriorated state of the lithium ion battery. The horizontal axis is the discharge amount Q, and the vertical axis is the rate of change of the battery voltage, that is, the absolute value of the derivative of the voltage V with respect to the discharge amount Q | dV / dQ |. The broken line is the initial state, and the solid line is the deteriorated state.
　本図に示す例においては、｜ｄＶ／ｄＱ｜の極値（ピーク）が明瞭に表れている。 In the example shown in this figure, the extreme value (peak) of | dV / dQ | appears clearly.
　初期状態と劣化状態とでは、極値の位置が異なっている。極値（極大値）の位置は、初期状態では放電量Ｑ０、劣化状態では放電量Ｑ１となっている。Ｑ１は、Ｑ０より少なくなっている。 The position of the extremum is different between the initial state and the deteriorated state. Position of the extreme value (maximum value), the amount of discharge in the initial state Q 0, and has a discharge amount Q 1 is in a degraded state. Q 1 is less than Q 0.
　この極値の位置は、非特許文献１に記載されているように、負極の所定の充電状態、すなわち黒鉛に挿入されたリチウムの密度が所定の値である状態に対応する。したがって、この極値の変化は、正極と負極との充電状態の対応関係が変化したことによるものであり、正極活物質の孤立、負極活物質の孤立、副反応によるリチウムイオンの固定化等が原因となって発生する。 The position of this extreme value corresponds to a predetermined charging state of the negative electrode, that is, a state in which the density of lithium inserted in graphite is a predetermined value, as described in Non-Patent Document 1. Therefore, this change in the extreme value is due to a change in the correspondence between the charging state of the positive electrode and the negative electrode, such as isolation of the positive electrode active material, isolation of the negative electrode active material, and immobilization of lithium ions due to side reactions. It occurs as a cause.
　なお、本図に示す初期状態及び劣化状態の放電曲線は、放電量Ｑが少ない段階で明瞭な最初のピークＱ０及びＱ１を有する。そこで、本明細書においては、初期状態におけるピークＱ０を「初期ピーク位置」と呼ぶことにする。 The discharge curves in the initial state and the deteriorated state shown in this figure have the first peaks Q 0 and Q 1 that are clear when the discharge amount Q is small. Therefore, in this specification, the peak Q 0 in the initial state is referred to as "initial peak position".
　ここで、副反応によるリチウムイオンの固定化が支配的である場合について説明する。 Here, the case where the immobilization of lithium ions by a side reaction is dominant will be described.
　この場合、放電量Ｑ０とＱ１との差（Ｑ０－Ｑ１）がリチウムイオンの固定化による影響とみなしてもよい。ここで、（Ｑ０－Ｑ１）は、「初期ピーク位置からの変化分」とも言うことができる。 In this case, the difference between the discharge amounts Q 0 and Q 1 (Q 0 −Q 1 ) may be regarded as the effect of the immobilization of lithium ions. Here, (Q 0- Q 1 ) can also be said to be "change from the initial peak position".
　この場合、（Ｑ０－Ｑ１）を容量回復量として、正極から容量回復極に（Ｑ０－Ｑ１）だけの電気量を放電することで、電池内部で容量回復極から正極に（Ｑ０－Ｑ１）の電気量に対応する量のリチウムイオンを移動させる。これにより、正極と負極との間の放電量のずれを解消して電池容量を回復させることができる。また、所定の閾値を設け、（Ｑ０－Ｑ１）が閾値以上である場合にのみ電池容量を回復させてもよい。 In this case, with (Q 0- Q 1 ) as the capacity recovery amount, by discharging the amount of electricity from the positive electrode to the capacity recovery electrode (Q 0- Q 1), the capacity recovery electrode becomes the positive electrode (Q 0-Q 1) inside the battery. Move an amount of lithium ions corresponding to the amount of electricity of 0- Q 1). As a result, the difference in the amount of discharge between the positive electrode and the negative electrode can be eliminated and the battery capacity can be recovered. Further, a predetermined threshold value may be set, and the battery capacity may be recovered only when (Q 0- Q 1 ) is equal to or higher than the threshold value.
　上記の方法により、正極活物質を２種類使用しない場合すなわち１種類の正極活物質を用いた場合であっても、容量回復量を判定することができる。 By the above method, the capacity recovery amount can be determined even when two types of positive electrode active materials are not used, that is, even when one type of positive electrode active material is used.
　図６は、本実施例の二次電池の容量回復方法をフロー図としてまとめて示したものである。 FIG. 6 shows a flow diagram of the capacity recovery method of the secondary battery of this embodiment.
　本図においては、まず、二次電池の電流、電圧等のデータを制御部に入力する（Ｓ１１０）。つぎに、入力されたデータに基づいて、図４のような二次電池の初期状態及び劣化状態の放電曲線のデータを算出する（Ｓ１２０）。 In this figure, first, data such as the current and voltage of the secondary battery are input to the control unit (S110). Next, based on the input data, the data of the discharge curves of the initial state and the deteriorated state of the secondary battery as shown in FIG. 4 is calculated (S120).
　つぎに、上記のデータから｜ｄＶ／ｄＱ｜を算出する（導関数算出工程）。そして、｜ｄＶ／ｄＱ｜の極値の有無を判別する（Ｓ１３０）。 Next, | dV / dQ | is calculated from the above data (derivative calculation process). Then, it is determined whether or not there is an extreme value of | dV / dQ | (S130).
　その極値が存在する場合、すなわち極値が明瞭である場合は、初期ピーク位置からの変化分（Ｑ０－Ｑ１）を計算する（Ｓ１４０）。 If the extremum exists, that is, if the extremum is clear, the change from the initial peak position (Q 0- Q 1 ) is calculated (S140).
　（Ｑ０－Ｑ１）と閾値とを比較し（Ｓ１５０）、（Ｑ０－Ｑ１）が閾値以上である場合は、二次電池の容量を回復する操作をする（Ｓ１６０）。（Ｑ０－Ｑ１）が閾値未満である場合は、二次電池の容量を回復する操作を行わない（Ｓ１７０）。 (Q 0- Q 1 ) is compared with the threshold value (S150), and if (Q 0- Q 1 ) is equal to or greater than the threshold value, an operation of recovering the capacity of the secondary battery is performed (S160). If (Q 0- Q 1 ) is less than the threshold value, the operation of recovering the capacity of the secondary battery is not performed (S170).
　なお、工程Ｓ１３０において極値が明瞭でない場合は、後述の実施例３に示すように再現計算処理を行い、必要に応じて二次電池の容量を回復する操作をする（Ｓ２００）。 If the extreme value is not clear in step S130, a reproduction calculation process is performed as shown in Example 3 described later, and an operation of recovering the capacity of the secondary battery is performed as necessary (S200).
　本実施例においては、放電曲線を用いる場合について説明したが、本発明は、これに限定されるものではなく、充電曲線を用いる場合にも同様に適用できる。 In this embodiment, the case where the discharge curve is used has been described, but the present invention is not limited to this, and can be similarly applied to the case where the charge curve is used.
　以下、本実施例に係る二次電池の容量回復方法をまとめて説明する。 Hereinafter, the method of recovering the capacity of the secondary battery according to this embodiment will be collectively described.
　二次電池の容量回復方法は、二次電池の充電曲線又は放電曲線から、充電量又は放電量Ｑに対する電圧Ｖの導関数の絶対値｜ｄＶ／ｄＱ｜を算出する工程と、二次電池の充電及び放電の繰り返しを行う前における｜ｄＶ／ｄＱ｜の１つの極値の位置である充電量又は放電量Ｑ０並びに二次電池の充電及び放電の繰り返しを行った後における｜ｄＶ／ｄＱ｜の１つの極値の位置である充電量又は放電量Ｑ１について、これらの差（Ｑ０－Ｑ１）が小さくなるように、容量回復極と正極又は負極との間で二次電池の反応種を移動させる容量回復工程と、を含む。 The capacity recovery method of the secondary battery includes a step of calculating the absolute value | dV / dQ | of the derivative of the voltage V with respect to the charge amount or the discharge amount Q from the charge curve or the discharge curve of the secondary battery, and the secondary battery. before performing the repetition of charge and discharge | dV / dQ | charge amount or discharge amount Q 0 and the position of one extreme of definitive after the repetition of charging and discharging of the secondary battery | dV / dQ | for one charge amount or discharge amount Q 1 is the position of the extreme value, as these differences (Q 0 -Q 1) becomes small, the reaction of the secondary battery with the capacity recovery electrode and a positive electrode or a negative electrode Includes a capacity recovery step to move the seeds.
　さらに、二次電池の容量回復方法は、差（Ｑ０－Ｑ１）が所定の閾値以上かどうかを判別する工程を含み、差（Ｑ０－Ｑ１）が所定の閾値以上である場合には、容量回復工程を行うことが望ましい。 Further, capacity recovery method for a secondary battery includes a step difference (Q 0 -Q 1) to determine whether more than a predetermined threshold value, if the difference (Q 0 -Q 1) is equal to or greater than the predetermined threshold value It is desirable to carry out a capacity recovery step.
　さらに、二次電池の容量回復方法は、二次電池の充電曲線又は放電曲線から、充電量又は放電量Ｑに対する電圧Ｖの導関数の絶対値｜ｄＶ／ｄＱ｜を算出する工程と、｜ｄＶ／ｄＱ｜の極値の有無を判別する工程と、を含み、極値がない場合には、正極・負極分離工程（再現計算処理）を行うことが望ましい。 Further, the capacity recovery method of the secondary battery includes a step of calculating the absolute value | dV / dQ | of the derivative of the voltage V with respect to the charge amount or the discharge amount Q from the charge curve or the discharge curve of the secondary battery, and | dV. It is desirable to perform a positive electrode / negative electrode separation step (reproduction calculation process) when there is no extreme value, including a step of determining the presence or absence of an extreme value of / dQ |.
　ただし、この方法では、正極・負極の活物質の孤立すなわち正極・負極自体の持つ容量の減少を無視しているため、もし負極の容量が減少している場合に、充電側で負極の容量が不足してリチウム金属が析出する懸念がある。 However, in this method, the isolation of the active material of the positive electrode and the negative electrode, that is, the decrease in the capacity of the positive electrode and the negative electrode itself is ignored. Therefore, if the capacity of the negative electrode is reduced, the capacity of the negative electrode is increased on the charging side. There is a concern that lithium metal will be deposited due to lack.
　そこで、電圧変化率の極値が複数個ある場合には、それぞれの極値に対応する放電量を特徴量とし、別の方法を用いて、上記の懸念を回避できる例について、次に説明する。 Therefore, when there are a plurality of extreme values of the voltage change rate, an example in which the above concern can be avoided by using the discharge amount corresponding to each extreme value as a feature quantity and using another method will be described below. ..
　図７は、１つの電圧変化率の曲線における複数の極値を特徴量として使用する場合について説明するためのグラフである。本図に示す曲線は、図５に示す曲線と同じである。 FIG. 7 is a graph for explaining a case where a plurality of extreme values in one voltage change rate curve are used as feature quantities. The curve shown in this figure is the same as the curve shown in FIG.
　本図のように、本実施例のリチウムイオン電池の電圧変化率には、２つの明確な極値が存在する。ここで、初期状態における極値に対する放電量を小さい方からＱ０Ａ、Ｑ０Ｂとし、劣化状態における極値に対する放電量を小さい方からＱ１Ａ、Ｑ１Ｂとする。これらの極値はいずれも、負極活物質に用いた黒鉛に由来し、黒鉛内部のリチウム密度が特定の値になったときに発生することが非特許文献２に記載されている。 As shown in this figure, there are two clear extreme values in the voltage change rate of the lithium ion battery of this embodiment. Here, the discharge amounts with respect to the extreme values in the initial state are Q 0A and Q 0B from the smallest, and the discharge amounts with respect to the extreme values in the deteriorated state are Q 1A and Q 1B from the smallest. It is described in Non-Patent Document 2 that all of these extreme values are derived from the graphite used as the negative electrode active material and occur when the lithium density inside the graphite reaches a specific value.
　したがって、２つの極値に対応する放電量の差（Ｑ０Ｂ－Ｑ０Ａ）及び（Ｑ１Ｂ－Ｑ１Ａ）はそれぞれ、初期状態及び劣化状態における負極容量の指標となる。この両者を比較し、例えば比率（Ｑ１Ｂ－Ｑ１Ａ）／（Ｑ０Ｂ－Ｑ０Ａ）が０．９未満のときには容量回復を実施せず、０．９以上のときには（Ｑ０Ａ－Ｑ１Ａ）だけ容量回復させる。なお、（Ｑ０Ｂ－Ｑ０Ａ）及び（Ｑ１Ｂ－Ｑ１Ａ）は、「２つのピーク間距離」又は「２つの極値の間の距離」とも言うことができる。 Therefore, the difference in the amount of discharge corresponding to the two extreme values (Q 0B −Q 0A ) and (Q 1B − Q 1A ) are indicators of the negative electrode capacity in the initial state and the deteriorated state, respectively. Comparing these two, for example, when the ratio (Q 1B- Q 1A ) / (Q 0B- Q 0A ) is less than 0.9, the capacity recovery is not performed, and when it is 0.9 or more (Q 0A- Q 1A ). Only recover capacity. In addition, (Q 0B −Q 0A ) and (Q 1B −Q 1A ) can also be referred to as “distance between two peaks” or “distance between two extrema”.
　上記の方法によれば、充電側のリチウム金属析出を回避しつつ、電池の容量を回復させることができる。 According to the above method, the capacity of the battery can be recovered while avoiding the precipitation of lithium metal on the charging side.
　図８は、本実施例の二次電池の容量回復方法をフロー図としてまとめて示したものである。 FIG. 8 shows a flow diagram of the capacity recovery method of the secondary battery of this embodiment.
　本図に示す工程の前提としては、図６の工程Ｓ１１０～Ｓ１３０がある。 As a premise of the process shown in this figure, there are steps S110 to S130 in FIG.
　図６の工程Ｓ１３０において、｜ｄＶ／ｄＱ｜の極値（ピーク）が２つ以上存在する場合、２つのピーク間距離（Ｑ０Ｂ－Ｑ０Ａ）及び（Ｑ１Ｂ－Ｑ１Ａ）を計算する（Ｓ３１０）。 In step S130 of FIG. 6, when there are two or more extreme values (peaks) of | dV / dQ |, the distance between the two peaks (Q 0B- Q 0A ) and (Q 1B- Q 1A ) are calculated (Q 1B-Q 1A). S310).
　そして、比率（Ｑ１Ｂ－Ｑ１Ａ）／（Ｑ０Ｂ－Ｑ０Ａ）を算出し、この比率が所定値以上かどうかを判別する（Ｓ３２０）。 Then, the ratio (Q 1B −Q 1A ) / (Q 0B −Q 0A ) is calculated, and it is determined whether or not this ratio is equal to or greater than a predetermined value (S320).
　比率が所定値以上である場合は、二次電池の容量を回復する操作をする（Ｓ３３０）。
比率が所定値未満である場合は、二次電池の容量を回復する操作を行わない（Ｓ３４０）。 When the ratio is equal to or higher than a predetermined value, an operation for recovering the capacity of the secondary battery is performed (S330).
If the ratio is less than a predetermined value, the operation of recovering the capacity of the secondary battery is not performed (S340).
　本実施例においては、放電曲線を用いる場合について説明したが、本発明は、これに限定されるものではなく、充電曲線を用いる場合にも同様に適用できる。 In this embodiment, the case where the discharge curve is used has been described, but the present invention is not limited to this, and can be similarly applied to the case where the charge curve is used.
　以下、本実施例に係る二次電池の容量回復方法をまとめて説明する。 Hereinafter, the method of recovering the capacity of the secondary battery according to this embodiment will be collectively described.
　二次電池の容量回復方法は、二次電池の充電及び放電の繰り返しを行う前における｜ｄＶ／ｄＱ｜の２つの極値の位置である充電量又は放電量Ｑ０Ａ及びＱ０Ｂ並びに二次電池の充電及び放電の繰り返しを行った後における｜ｄＶ／ｄＱ｜の２つの極値の位置である充電量又は放電量Ｑ１Ａ及びＱ１Ｂについて、前記繰り返しの前後のそれぞれにおける２つの極値の位置の差（Ｑ０Ｂ－Ｑ０Ａ）及び（Ｑ１Ｂ－Ｑ１Ａ）を指標として、二次電池の容量を回復する操作の要否を判別する工程を含む。 The capacity recovery method of the secondary battery is as follows: the charge amount or discharge amount Q 0A and Q 0B , which are the positions of the two extreme values of | dV / dQ | before the secondary battery is repeatedly charged and discharged, and the secondary battery. Regarding the charge amount or discharge amount Q 1A and Q 1B , which are the positions of the two extreme values of | dV / dQ | after the repetition of charging and discharging, the positions of the two extreme values before and after the repetition. (Q 0B- Q 0A ) and (Q 1B- Q 1A ) are used as indexes to determine the necessity of an operation for recovering the capacity of the secondary battery.
　ただし、上記の方法によっても、正極活物質の孤立すなわち正極容量の減少は検出できない。そのため、正極容量が想定よりも減少していた場合に容量回復極から正極にリチウムイオンを大量に移動させると、正極電位が想定よりも低下し、極端な場合には過放電状態に陥る。 However, even with the above method, isolation of the positive electrode active material, that is, a decrease in the positive electrode capacity cannot be detected. Therefore, if a large amount of lithium ions are moved from the capacity recovery electrode to the positive electrode when the positive electrode capacity is lower than expected, the positive electrode potential is lower than expected, and in an extreme case, an over-discharged state occurs.
　この懸念に対処するためには、電池の充放電曲線を解析して正極及び負極の充放電曲線を推定し、所定の正極電位と所定の負極電位が一致するように容量回復量を設定することが望ましい。 To deal with this concern, the charge / discharge curves of the battery should be analyzed to estimate the charge / discharge curves of the positive and negative electrodes, and the capacity recovery amount should be set so that the predetermined positive electrode potential and the predetermined negative electrode potential match. Is desirable.
　図９は、リチウムイオン電池、正極及び負極の放電曲線並びに容量回復量の算出方法を概念的に説明するためのグラフである。電池の放電曲線は、電流計及び電圧計の出力値から算出した測定値であり、正極及び負極の放電曲線は、回帰計算処理（再現計算処理）で得た計算値である。実線がリチウムイオン電池の放電曲線、破線が正極の放電曲線、点線が負極の放電曲線である。 FIG. 9 is a graph for conceptually explaining the discharge curves of the lithium ion battery, the positive electrode and the negative electrode, and the calculation method of the capacity recovery amount. The discharge curve of the battery is a measured value calculated from the output values of the ammeter and the voltmeter, and the discharge curves of the positive electrode and the negative electrode are the calculated values obtained by the regression calculation process (reproduction calculation process). The solid line is the discharge curve of the lithium-ion battery, the broken line is the discharge curve of the positive electrode, and the dotted line is the discharge curve of the negative electrode.
　本図は、リチウムイオン電池の放電曲線を正極及び負極の放電曲線に分離する放電曲線解析を用いて作成したものである。 This figure was created using a discharge curve analysis that separates the discharge curve of the lithium-ion battery into the discharge curves of the positive electrode and the negative electrode.
　再現計算処理は、例えば、補正パラメータｍｐ、ｍｎ、Ｃｐ、Ｃｎを用いて、次のように行う。 The reproduction calculation process is performed as follows, for example, using the correction parameters m p , mn , C p , and C n .
　まず、図３に示す充放電装置３５０の制御部３５５に記録してある正極及び負極の基準質量もしくは基準面積あたりの放電曲線について、それぞれの放電量にｍｐ、ｍｎを掛けた後に、Ｃｐ、Ｃｎを加えて補正して、正極及び負極の放電曲線の計算値を得る。 First, the discharge curve per reference mass or reference area of the positive electrode and the negative electrode is recorded in the control unit 355 of the rechargeable device 350 shown in FIG. 3, after multiplying m p, a m n in the respective discharge amounts, C The calculated values of the discharge curves of the positive electrode and the negative electrode are obtained by adding p and C n for correction.
　このようにして得た正極及び負極の放電曲線の計算値について、同じ放電量に対応する正極電位と負極電位との差を求めることで、電池の放電曲線の計算値が得られる。電池の放電曲線の計算値が測定値と一致するように、正極及び負極の容量の補正パラメータｍｐ、ｍｎ、Ｃｐ、Ｃｎを調整する。 With respect to the calculated values of the discharge curves of the positive electrode and the negative electrode thus obtained, the calculated value of the discharge curve of the battery can be obtained by obtaining the difference between the positive electrode potential and the negative electrode potential corresponding to the same discharge amount. The correction parameters m p , mn , C p , and C n of the positive electrode and negative electrode capacities are adjusted so that the calculated value of the discharge curve of the battery matches the measured value.
　上記の再現計算処理は、特許文献２に記載されている。 The above reproduction calculation process is described in Patent Document 2.
　このように計算で得た正極及び負極の放電曲線について、所定の充電状態に対応する放電量を算出する。言い換えると、所定の充電状態に対応する正極電位及び負極電位のそれぞれに対応する放電量を算出する。 For the discharge curves of the positive electrode and the negative electrode obtained by the calculation in this way, the discharge amount corresponding to the predetermined charging state is calculated. In other words, the discharge amount corresponding to each of the positive electrode potential and the negative electrode potential corresponding to a predetermined charging state is calculated.
　具体的には、図９に示すような所定の正極電位Ｖｐ０に対応する放電量Ｑｐ０を求める。また、所定の負極電位Ｖｎ０に対応する放電量Ｑｎ０を求める。その後、両者の差（Ｑｐ０－Ｑｎ０）に対応する量のリチウムイオンを容量回復極から正極に移動させる。ここで、Ｖｐ０及びＶｎ０は、電池の所定の充電状態（同一の充電状態）に対応する正極及び負極の電位である。 Specifically, the discharge amount Q p0 corresponding to the predetermined positive electrode potential V p0 as shown in FIG. 9 is obtained. Further, the discharge amount Q n0 corresponding to the predetermined negative electrode potential V n0 is obtained. Then, an amount of lithium ions corresponding to the difference between the two (Q p0 −Q n0 ) is moved from the capacity recovery electrode to the positive electrode. Here, V p0 and V n0 are potentials of the positive electrode and the negative electrode corresponding to a predetermined charging state (same charging state) of the battery.
　もし（Ｑｐ０－Ｑｎ０）＜０の場合には、（Ｑｐ０－Ｑｎ０）に対応する量のリチウムイオンを正極から容量回復極に移動させる。あるいは、（Ｑｐ０－Ｑｎ０）が所定の閾値以上の場合にのみ、もしくは（Ｑｐ０－Ｑｎ０）が所定の領域の範囲外にあるときのみ、電池容量を回復させてもよい。 If (Q p0- Q n0 ) <0, the amount of lithium ions corresponding to (Q p0- Q n0 ) is moved from the positive electrode to the capacity recovery electrode. Alternatively, (Q p0 -Q n0) only when the predetermined threshold value or more, or (Q p0 -Q n0) only when that is outside the range of the predetermined region, may be recovered to the battery capacity.
　これにより、回復後には、正極電位がＶｐ０のときに負極電位がＶｎ０になるようになる。負極電位Ｖｎ０を例えば０．８Ｖとして、負極電位が急速に立ち上がる箇所に設定しておけば、電池の放電終了時の負極電位はＶｎ０に近い値となり、したがって、正極電位はＶｐ０となる。すなわち、電池の放電時に正極の開回路電位がＶｐ０以下にならず、正極の過放電を回避できる。これにより、容量回復後の電池劣化を抑制することができる。 As a result, after recovery, the negative electrode potential becomes V n0 when the positive electrode potential is V p0 . If the negative electrode potential V n0 is set to, for example, 0.8 V and set at a position where the negative electrode potential rises rapidly, the negative electrode potential at the end of battery discharge becomes a value close to V n0 , and therefore the positive electrode potential becomes V p0. .. That is, when the battery is discharged, the open circuit potential of the positive electrode does not become V p0 or less, and over-discharging of the positive electrode can be avoided. As a result, deterioration of the battery after capacity recovery can be suppressed.
　図１０は、本実施例の二次電池の容量回復方法をフロー図としてまとめて示したものである。 FIG. 10 summarizes the capacity recovery method of the secondary battery of this embodiment as a flow chart.
　前提となる図６において、極値が明瞭でない場合（Ｓ１３０）、工程Ｓ２００に進む。 In FIG. 6, which is a premise, if the extreme value is not clear (S130), the process proceeds to step S200.
　そして、図１０の充電曲線又は放電曲線を正極及び負極の充電曲線又は放電曲線に分離する（Ｓ４１０：正極・負極分離工程）。つぎに、正極及び負極それぞれについて、所定の電位に対応する容量を抽出する（Ｓ４２０）。正極と負極との容量の差分（Ｑｐ０－Ｑｎ０）を計算し（Ｓ４３０）、差分が閾値以上かどうかを判別する（Ｓ４４０）。 Then, the charge curve or discharge curve of FIG. 10 is separated into the charge curve or discharge curve of the positive electrode and the negative electrode (S410: positive electrode / negative electrode separation step). Next, the capacitance corresponding to a predetermined potential is extracted for each of the positive electrode and the negative electrode (S420). The difference in capacitance between the positive electrode and the negative electrode (Q p0 −Q n0 ) is calculated (S430), and it is determined whether or not the difference is equal to or greater than the threshold value (S440).
　差分が閾値以上である場合は、二次電池の容量を回復する操作をする（Ｓ４５０）。差分が閾値未満である場合は、二次電池の容量を回復する操作を行わない（Ｓ４６０）。 If the difference is greater than or equal to the threshold value, perform an operation to recover the capacity of the secondary battery (S450). If the difference is less than the threshold value, the operation of recovering the capacity of the secondary battery is not performed (S460).
　なお、Ｑｎ０及びＱ１はどちらも負極由来の指数であるため、Ｑｎ０の代わりに、上記の電圧変化率の極値に対応するＱ１を用いることもできる。 Since both Q n0 and Q 1 are indices derived from the negative electrode, Q 1 corresponding to the above-mentioned extreme value of the voltage change rate can be used instead of Q n 0.
　本実施例においては、放電曲線を用いる場合について説明したが、本発明は、これに限定されるものではなく、充電曲線を用いる場合にも同様に適用できる。 In this embodiment, the case where the discharge curve is used has been described, but the present invention is not limited to this, and can be similarly applied to the case where the charge curve is used.
　以下、本実施例に係る二次電池の容量回復方法をまとめて説明する。 Hereinafter, the method of recovering the capacity of the secondary battery according to this embodiment will be collectively described.
　二次電池の容量回復方法は、二次電池の充電曲線又は放電曲線を、正極及び負極の充電曲線又は放電曲線に分離する正極・負極分離工程と、正極及び負極のそれぞれの充電曲線又は放電曲線について、正極及び負極のそれぞれについての所定の電位Ｖｐ０及びＶｎ０に対応する容量Ｑｐ０及びＱｎ０を抽出し、これらの容量の差分の絶対値｜Ｑｐ０－Ｑｎ０｜を算出する工程と、差分の絶対値｜Ｑｐ０－Ｑｎ０｜が小さくなるように、容量回復極と正極又は負極との間で二次電池の反応種を移動させる容量回復工程と、を含む。 The capacity recovery method of the secondary battery includes a positive electrode / negative electrode separation step of separating the charge curve or discharge curve of the secondary battery into a charge curve or discharge curve of the positive electrode and the negative electrode, and a charge curve or discharge curve of the positive electrode and the negative electrode, respectively. With respect to the step of extracting the capacitances Q p0 and Q n0 corresponding to the predetermined potentials V p0 and V n0 for each of the positive electrode and the negative electrode, and calculating the absolute value | Q p0 −Q n0 | of the difference between these capacitances. , A capacity recovery step of moving the reaction species of the secondary battery between the capacity recovery electrode and the positive electrode or the negative electrode so that the absolute value of the difference | Q p0 −Q n0 | becomes small.
　さらに、二次電池の容量回復方法は、差分の絶対値｜Ｑｐ０－Ｑｎ０｜が所定の閾値以上かどうかを判別する工程を含み、差分の絶対値｜Ｑｐ０－Ｑｎ０｜が所定の閾値以上である場合には、容量回復工程を行うことが望ましい。 Further, capacity recovery method for a secondary battery, the absolute value of the difference | Q p0 -Q n0 | comprises the step of determining whether more than a predetermined threshold value, the absolute value of the difference | Q p0 -Q n0 | is given If it is equal to or higher than the threshold value, it is desirable to perform a capacity recovery step.
　なお、本実施例の上述の説明においては、図６において極値が明瞭でない場合（Ｓ１３０）に工程Ｓ２００に進むことを前提としているが、本実施例の方法は、これに限定されるものではなく、極値の判別をすることなく、最初から図１０の工程Ｓ４１０の再現計算処理を行い、工程Ｓ４２０以降の処理をしてもよい。 In the above description of this embodiment, it is assumed that the process proceeds to step S200 when the extreme value is not clear in FIG. 6 (S130), but the method of this embodiment is not limited to this. Instead, the reproduction calculation process of the step S410 of FIG. 10 may be performed from the beginning, and the processes after the step S420 may be performed without discriminating the extreme value.
　また、再現計算処理の後、正極及び負極それぞれの充電曲線又は放電曲線から、導関数｜ｄＶ／ｄＱ｜を算出し、｜ｄＶ／ｄＱ｜の極値を用いて、図６の工程Ｓ１４０以降又は図８の工程Ｓ３１０以降の処理をしてもよい。 Further, after the reproduction calculation process, the derivative | dV / dQ | is calculated from the charge curve or the discharge curve of each of the positive electrode and the negative electrode, and the extreme value of | dV / dQ | is used after step S140 in FIG. The processing after the step S310 of FIG. 8 may be performed.
　図１１は、再現計算処理の後、正極の放電曲線から導関数の絶対値｜ｄＶ／ｄｑ｜を算出した例を示すグラフである。横軸は正極活物資の質量当たりの放電量ｑであり、縦軸は正極の電位の変化率すなわち放電量ｑに対する電圧Ｖの導関数の絶対値｜ｄＶ／ｄｑ｜である。 FIG. 11 is a graph showing an example in which the absolute value | dV / dq | of the derivative is calculated from the discharge curve of the positive electrode after the reproduction calculation process. The horizontal axis is the discharge amount q per mass of the positive electrode active material, and the vertical axis is the rate of change in the potential of the positive electrode, that is, the absolute value of the derivative of the voltage V with respect to the discharge amount q | dV / dq |.
　図１２は、再現計算処理の後、負極の放電曲線から導関数の絶対値｜ｄＶ／ｄｑ｜を算出した例を示すグラフである。横軸は負極活物資の質量当たりの放電量ｑであり、縦軸は負極の電位の変化率すなわち放電量ｑに対する電圧Ｖの導関数の絶対値｜ｄＶ／ｄｑ｜である。 FIG. 12 is a graph showing an example in which the absolute value | dV / dq | of the derivative is calculated from the discharge curve of the negative electrode after the reproduction calculation process. The horizontal axis is the discharge amount q per mass of the negative electrode active material, and the vertical axis is the rate of change of the potential of the negative electrode, that is, the absolute value of the derivative of the voltage V with respect to the discharge amount q | dV / dq |.
　図１１においては、｜ｄＶ／ｄｑ｜の極値が得られないが、図１２においては、２つの極値が明瞭に表れている。この場合には、図１２の２つの極値のいずれか一方を用いて、図６の工程Ｓ１４０以降の処理をすることもでき、図１２の２つの極値の両方を用いて、図８の工程Ｓ３１０以降の処理をすることもできる。 In FIG. 11, the extreme values of | dV / dq | cannot be obtained, but in FIG. 12, the two extreme values are clearly shown. In this case, one of the two extrema of FIG. 12 can be used to perform the processing after the step S140 of FIG. 6, and both of the two extrema of FIG. 12 can be used to perform the process of FIG. The processing after the step S310 can also be performed.
　実施例１～３に係る技術的思想をまとめると次のようになる。 The technical ideas related to Examples 1 to 3 can be summarized as follows.
　正極、負極、及び第三極としての容量回復極を有する二次電池の容量を回復する方法であって、二次電池の充電曲線又は放電曲線から、所定の充電状態に対応する２つ以上の放電量を算出する工程と、前記２つ以上の放電量のうちの所定の２つの放電量の差を指標とし、この差の絶対値が小さくなるように、容量回復極と正極又は負極との間で二次電池の反応種を移動させる容量回復工程と、を含む。 A method of recovering the capacity of a secondary battery having a positive electrode, a negative electrode, and a capacity recovery electrode as a third pole, and two or more corresponding to a predetermined charging state from the charging curve or the discharging curve of the secondary battery. Using the difference between the step of calculating the discharge amount and the predetermined two discharge amounts of the two or more discharge amounts as an index, the capacity recovery electrode and the positive electrode or the negative electrode are set so that the absolute value of this difference becomes small. It includes a capacity recovery step of moving the reactive species of the secondary battery between.
　以下、本発明の他の実施形態について説明する。 Hereinafter, other embodiments of the present invention will be described.
　図１のセル１００の場合、正極、負極及び容量回復極を内蔵し、封止されているが、本発明は、封止していないセルについても適用可能である。 In the case of the cell 100 of FIG. 1, the positive electrode, the negative electrode and the capacity recovery electrode are built-in and sealed, but the present invention can be applied to the unsealed cell.
　例えば、セルの製造段階において、正極・負極を捲回あるいは積層して容器に設置し、その容器に電解液を注液し、封止せずに充放電する。なお、容器としては、製品の封止前の電池容器でもよいが、正極、負極及び容量回復極を電解液に浸漬するための別の容器であってもよい。 For example, in the cell manufacturing stage, the positive electrode and the negative electrode are wound or laminated and installed in a container, and the electrolytic solution is injected into the container and charged / discharged without sealing. The container may be a battery container before sealing the product, but may be another container for immersing the positive electrode, the negative electrode, and the capacity recovery electrode in the electrolytic solution.
　一般的なリチウムイオン電池においては、負極表面に被膜を形成する副反応によって正極と負極との放電量のずれが生じる。この段階で、容量回復極を一時的に容器に導入し、上述のいずれかの方法により容量回復極と正極または負極との間でリチウムイオンを移動させる。その後、容量回復極を撤去した後、セルを封止する。 In a general lithium-ion battery, a deviation in the amount of discharge between the positive electrode and the negative electrode occurs due to a side reaction that forms a film on the surface of the negative electrode. At this stage, the capacitance recovery electrode is temporarily introduced into the container, and lithium ions are transferred between the capacitance recovery electrode and the positive electrode or the negative electrode by any of the above methods. Then, after removing the capacity recovery electrode, the cell is sealed.
　この方法によれば、初期段階で発生するセルの容量減少分を容量回復処理によって補い、かつ、追加の副反応発生を抑制できるため、従来のリチウムイオン電池と同様の二極式セルを長寿命化することができる。 According to this method, the capacity reduction of the cell generated in the initial stage can be compensated by the capacity recovery process, and the occurrence of additional side reactions can be suppressed, so that the bipolar cell similar to the conventional lithium ion battery has a long life. Can be transformed into.
　すなわち、本実施形態は、リチウムイオン電池（二次電池）の製造方法に関するものである。この場合、容量回復極は、「容量調整極」と言い換えてもよい。 That is, the present embodiment relates to a method for manufacturing a lithium ion battery (secondary battery). In this case, the capacity recovery pole may be rephrased as a "capacity adjustment pole".
　以下、本実施例に係る二次電池の製造方法をまとめて説明する。 Hereinafter, the method for manufacturing the secondary battery according to this embodiment will be collectively described.
　二次電池の製造方法は、二次電池の正極及び負極を充電及び放電が可能な状態に設置する工程と、第三極としての容量調整極を、正極及び負極の少なくともいずれかとの間で二次電池の反応種を移動させることができるように設置する工程と、二次電池の充電曲線又は放電曲線を取得する工程と、二次電池の充電曲線又は放電曲線を、正極及び負極の充電曲線又は放電曲線に分離する正極・負極分離工程と、正極及び負極のそれぞれの充電曲線又は放電曲線について、正極及び負極のそれぞれについての所定の電位Ｖｐ０及びＶｎ０に対応する容量Ｑｐ０及びＱｎ０を抽出し、これらの容量の差分の絶対値｜Ｑｐ０－Ｑｎ０｜を算出する工程と、差分の絶対値｜Ｑｐ０－Ｑｎ０｜が小さくなるように、容量調整極と正極又は負極との間で二次電池の反応種を移動させる容量調整工程と、を含む。 The method for manufacturing the secondary battery is a step of installing the positive electrode and the negative electrode of the secondary battery in a state where they can be charged and discharged, and a capacity adjusting electrode as the third electrode between at least one of the positive electrode and the negative electrode. The process of installing the reaction type of the secondary battery so that it can be moved, the process of acquiring the charge curve or discharge curve of the secondary battery, and the charge curve or discharge curve of the secondary battery are the charge curves of the positive electrode and the negative electrode. Alternatively, for the positive electrode / negative electrode separation step of separating into a discharge curve and the charge curve or discharge curve of the positive electrode and the negative electrode, respectively, the capacities Q p0 and Q n0 corresponding to the predetermined potentials V p0 and V n0 for the positive electrode and the negative electrode, respectively. And the process of calculating the absolute value | Q p0- Q n0 | of the difference between these capacitances, and the capacitance adjusting electrode and the positive electrode or the negative electrode so that the absolute value | Q p0- Q n0 | of the difference becomes small. It includes a capacity adjusting step of moving the reaction species of the secondary battery between.
　さらに、二次電池の製造方法は、差分の絶対値｜Ｑｐ０－Ｑｎ０｜が所定の閾値以上かどうかを判別する工程を含み、差分の絶対値｜Ｑｐ０－Ｑｎ０｜が所定の閾値以上である場合には、容量調整工程を行うことが望ましい。 Furthermore, the manufacturing method of the secondary battery, the absolute value of the difference | Q p0 -Q n0 | comprises the step of determining whether more than a predetermined threshold value, the absolute value of the difference | Q p0 -Q n0 | a predetermined threshold value In the above cases, it is desirable to perform the capacity adjusting step.
　本発明は、上記の実施形態に限定されるものではなく、本発明の特徴を損なわない限り、本発明の技術思想の範囲内で考えられるその他の形態についても、本発明の範囲内に含まれる。 The present invention is not limited to the above-described embodiment, and other embodiments that can be considered within the scope of the technical idea of the present invention are also included within the scope of the present invention as long as the features of the present invention are not impaired. ..
　１：電極部分、２：正極端子、３：負極端子、４：容量回復極端子、５：セパレータ、６：外装材、１１：正極、１２：負極、１５：容量回復極、１００：セル、３００：電池パック、３５０：充放電装置、３５１：電流計、３５２：電圧計、３５３：抵抗、３５４：電源、３５５：制御部、３５６：充放電切り替えスイッチ、３５７：容量回復スイッチ。 1: Electrode part 2: Positive terminal 3: Negative electrode terminal 4: Capacity recovery electrode terminal 5: Separator, 6: Exterior material, 11: Positive electrode, 12: Negative electrode, 15: Capacity recovery electrode, 100: Cell, 300 : Battery pack, 350: Charge / discharge device, 351: Current meter, 352: Voltage meter, 353: Resistance, 354: Power supply, 355: Control unit, 356: Charge / discharge changeover switch, 357: Capacity recovery switch.

Claims (11)

  1. 　正極、負極、及び第三極としての容量回復極を有する二次電池の容量を回復する方法であって、
    　前記二次電池の充電曲線又は放電曲線から、所定の充電状態に対応する２つ以上の放電量を算出する工程と、
    　前記２つ以上の放電量のうちの所定の２つの放電量の差を指標とし、この差の絶対値が小さくなるように、前記容量回復極と前記正極又は前記負極との間で前記二次電池の反応種を移動させる容量回復工程と、を含む、二次電池の容量回復方法。     A method of recovering the capacity of a secondary battery having a positive electrode, a negative electrode, and a capacity recovery electrode as a third electrode.
    A step of calculating two or more discharge amounts corresponding to a predetermined charge state from the charge curve or discharge curve of the secondary battery, and
    Using the difference between two predetermined discharge amounts out of the two or more discharge amounts as an index, the secondary between the positive electrode or the negative electrode so that the absolute value of the difference becomes small. A method for recovering the capacity of a secondary battery, which includes a capacity recovery step of moving the reaction type of the battery.
  2. 　前記正極を構成する正極活物質は、１種類である、請求項１記載の二次電池の容量回復方法。 The method for recovering the capacity of a secondary battery according to claim 1, wherein the positive electrode active material constituting the positive electrode is one type.
  3. 　正極、負極、及び第三極としての容量回復極を有する二次電池の容量を回復する方法であって、
    　前記二次電池の充電曲線又は放電曲線から、前記正極の所定の充電状態又は電位に対応する前記二次電池の放電量、及び前記負極の所定の充電状態又は電位に対応する前記二次電池の放電量のうち２つ以上の放電量を算出する工程と、
    　前記２つ以上の放電量のうちの所定の２つの放電量の差を指標とし、この差の絶対値が小さくなるように、前記容量回復極と前記正極又は前記負極との間で前記二次電池の反応種を移動させる容量回復工程と、を含む、二次電池の容量回復方法。     A method of recovering the capacity of a secondary battery having a positive electrode, a negative electrode, and a capacity recovery electrode as a third electrode.
    From the charge curve or discharge curve of the secondary battery, the discharge amount of the secondary battery corresponding to the predetermined charge state or potential of the positive electrode, and the discharge amount of the secondary battery corresponding to the predetermined charge state or potential of the negative electrode. The process of calculating the amount of discharge of two or more of the amount of discharge, and
    Using the difference between two predetermined discharge amounts out of the two or more discharge amounts as an index, the secondary between the positive electrode or the negative electrode so that the absolute value of the difference becomes small. A method for recovering the capacity of a secondary battery, which includes a capacity recovery step of moving the reaction type of the battery.
  4. 　正極、負極、及び第三極としての容量回復極を有する二次電池の容量を回復する方法であって、
    　前記二次電池の充電曲線又は放電曲線から、充電量又は放電量Ｑに対する電圧Ｖの導関数の絶対値｜ｄＶ／ｄＱ｜を算出する工程と、
    　前記二次電池の充電及び放電の繰り返しを行う前における前記｜ｄＶ／ｄＱ｜の１つの極値の位置である充電量又は放電量Ｑ０並びに前記二次電池の充電及び放電の繰り返しを行った後における前記｜ｄＶ／ｄＱ｜の前記１つの極値の位置である充電量又は放電量Ｑ１について、これらの差（Ｑ０－Ｑ１）が小さくなるように、前記容量回復極と前記正極又は前記負極との間で前記二次電池の反応種を移動させる容量回復工程と、を含む、二次電池の容量回復方法。     A method of recovering the capacity of a secondary battery having a positive electrode, a negative electrode, and a capacity recovery electrode as a third electrode.
    A step of calculating the absolute value | dV / dQ | of the derivative of the voltage V with respect to the charge amount or the discharge amount Q from the charge curve or the discharge curve of the secondary battery.
    Wherein before performing the repetition of charging and discharging of the secondary battery | were one charge and repeating the discharging amount of charge or discharge amount Q 0 and the secondary battery which is a position of the extreme value of | dV / dQ wherein after | dV / dQ | above for one charge amount or discharge amount Q 1 is the position of the extreme values of these differences (Q 0 -Q 1) so decreases, the said capacity recovery electrode positive Alternatively, a method for recovering the capacity of a secondary battery, which comprises a capacity recovery step of moving a reaction type of the secondary battery to and from the negative electrode.
  5. 　さらに、前記差（Ｑ０－Ｑ１）が所定の閾値以上かどうかを判別する工程を含み、
    　前記差（Ｑ０－Ｑ１）が前記所定の閾値以上である場合には、前記容量回復工程を行う、請求項４記載の二次電池の容量回復方法。     Further, the step of determining whether or not the difference (Q 0- Q 1 ) is equal to or higher than a predetermined threshold value is included.
    The method for recovering the capacity of a secondary battery according to claim 4, wherein when the difference (Q 0- Q 1 ) is equal to or greater than the predetermined threshold value, the capacity recovery step is performed.
  6. 　さらに、前記二次電池の充電及び放電の繰り返しを行う前における前記｜ｄＶ／ｄＱ｜の２つの極値の位置である充電量又は放電量Ｑ０Ａ及びＱ０Ｂ並びに前記二次電池の充電及び放電の繰り返しを行った後における前記｜ｄＶ／ｄＱ｜の前記２つの極値の位置である充電量又は放電量Ｑ１Ａ及びＱ１Ｂについて、前記繰り返しの前後のそれぞれにおける前記２つの極値の位置の差（Ｑ０Ｂ－Ｑ０Ａ）及び（Ｑ１Ｂ－Ｑ１Ａ）を指標として、二次電池の容量を回復する操作の要否を判別する工程を含む、請求項５記載の二次電池の容量回復方法。 Further, the charge amount or discharge amount Q 0A and Q 0B , which are the positions of the two extreme values of | dV / dQ | before the secondary battery is repeatedly charged and discharged, and the secondary battery is charged and discharged. With respect to the charge amount or discharge amount Q 1A and Q 1B , which are the positions of the two extreme values of | dV / dQ | after the repetition of the above, the positions of the two extreme values before and after the repetition are respectively. The capacity recovery of the secondary battery according to claim 5, which includes a step of determining whether or not an operation for recovering the capacity of the secondary battery is necessary using the difference (Q 0B- Q 0A ) and (Q 1B- Q 1A) as indexes. Method.
  7. 　正極、負極、及び第三極としての容量回復極を有する二次電池の容量を回復する方法であって、
    　前記二次電池の充電曲線又は放電曲線を、前記正極及び前記負極の充電曲線又は放電曲線に分離する正極・負極分離工程と、
    　前記正極及び前記負極のそれぞれの前記充電曲線又は前記放電曲線について、前記正極及び前記負極のそれぞれについての所定の電位Ｖｐ０及びＶｎ０に対応する容量Ｑｐ０及びＱｎ０を抽出し、これらの容量の差分の絶対値｜Ｑｐ０－Ｑｎ０｜を算出する工程と、　前記差分の絶対値｜Ｑｐ０－Ｑｎ０｜が小さくなるように、前記容量回復極と前記正極又は前記負極との間で前記二次電池の反応種を移動させる容量回復工程と、を含む、二次電池の容量回復方法。     A method of recovering the capacity of a secondary battery having a positive electrode, a negative electrode, and a capacity recovery electrode as a third electrode.
    A positive electrode / negative electrode separation step of separating the charge curve or discharge curve of the secondary battery into a charge curve or discharge curve of the positive electrode and the negative electrode.
    With respect to the charge curve or the discharge curve of each of the positive electrode and the negative electrode, the capacities Q p0 and Q n0 corresponding to the predetermined potentials V p0 and V n0 for the positive electrode and the negative electrode, respectively, are extracted, and these capacities are extracted. the absolute value of the difference | calculating a absolute value of the difference | | Q p0 -Q n0 Q p0 -Q n0 | so becomes small, between said capacity recovery electrode positive electrode or the negative electrode A method for recovering the capacity of a secondary battery, which comprises a capacity recovery step of moving the reaction species of the secondary battery.
  8. 　さらに、前記差分の絶対値｜Ｑｐ０－Ｑｎ０｜が所定の閾値以上かどうかを判別する工程を含み、
    　前記差分の絶対値｜Ｑｐ０－Ｑｎ０｜が前記所定の閾値以上である場合には、前記容量回復工程を行う、請求項７記載の二次電池の容量回復方法。     Further, a step of determining whether or not the absolute value | Q p0 −Q n0 | of the difference is equal to or higher than a predetermined threshold value is included.
    The method for recovering the capacity of a secondary battery according to claim 7, wherein when the absolute value | Q p0 −Q n0 | of the difference is equal to or greater than the predetermined threshold value, the capacity recovery step is performed.
  9. 　さらに、前記二次電池の前記充電曲線又は前記放電曲線から、充電量又は放電量Ｑに対する電圧Ｖの導関数の絶対値｜ｄＶ／ｄＱ｜を算出する工程と、
    　前記｜ｄＶ／ｄＱ｜の極値の有無を判別する工程と、を含み、
    　前記極値がない場合には、前記正極・負極分離工程を行う、請求項７又は８に記載の二次電池の容量回復方法。     Further, a step of calculating the absolute value | dV / dQ | of the derivative of the voltage V with respect to the charge amount or the discharge amount Q from the charge curve or the discharge curve of the secondary battery.
    Including the step of determining the presence or absence of an extreme value of | dV / dQ |.
    The method for recovering the capacity of a secondary battery according to claim 7 or 8, wherein if there is no extreme value, the positive electrode / negative electrode separation step is performed.
  10. 　二次電池の正極及び負極を充電及び放電が可能な状態に設置する工程と、
    　第三極としての容量調整極を、前記正極及び前記負極の少なくともいずれかとの間で前記二次電池の反応種を移動させることができるように設置する工程と、
    　前記二次電池の充電曲線又は放電曲線を取得する工程と、
    　前記二次電池の前記充電曲線又は前記放電曲線を、前記正極及び前記負極の充電曲線又は放電曲線に分離する正極・負極分離工程と、
    　前記正極及び前記負極のそれぞれの前記充電曲線又は前記放電曲線について、前記正極及び前記負極のそれぞれについての所定の電位Ｖｐ０及びＶｎ０に対応する容量Ｑｐ０及びＱｎ０を抽出し、これらの容量の差分の絶対値｜Ｑｐ０－Ｑｎ０｜を算出する工程と、　前記差分の絶対値｜Ｑｐ０－Ｑｎ０｜が小さくなるように、前記容量調整極と前記正極又は前記負極との間で前記二次電池の反応種を移動させる容量調整工程と、を含む、二次電池の製造方法。     The process of installing the positive and negative electrodes of the secondary battery in a state where it can be charged and discharged, and
    A step of installing the capacity adjusting electrode as the third electrode so that the reaction type of the secondary battery can be moved between at least one of the positive electrode and the negative electrode.
    The step of acquiring the charge curve or the discharge curve of the secondary battery, and
    A positive electrode / negative electrode separation step of separating the charge curve or the discharge curve of the secondary battery into the charge curve or the discharge curve of the positive electrode and the negative electrode.
    With respect to the charge curve or the discharge curve of each of the positive electrode and the negative electrode, the capacities Q p0 and Q n0 corresponding to the predetermined potentials V p0 and V n0 for the positive electrode and the negative electrode, respectively, are extracted, and these capacities are extracted. the absolute value of the difference | calculating a absolute value of the difference | | Q p0 -Q n0 Q p0 -Q n0 | so becomes small, between said capacity adjustment pole positive electrode or the negative electrode A method for manufacturing a secondary battery, which comprises a capacity adjusting step of moving the reaction type of the secondary battery.
  11. 　さらに、前記差分の絶対値｜Ｑｐ０－Ｑｎ０｜が所定の閾値以上かどうかを判別する工程を含み、
    　前記差分の絶対値｜Ｑｐ０－Ｑｎ０｜が前記所定の閾値以上である場合には、前記容量調整工程を行う、請求項１０記載の二次電池の製造方法。     Further, a step of determining whether or not the absolute value | Q p0 −Q n0 | of the difference is equal to or higher than a predetermined threshold value is included.
    The method for manufacturing a secondary battery according to claim 10, wherein when the absolute value | Q p0 −Q n0 | of the difference is equal to or greater than the predetermined threshold value, the capacity adjusting step is performed.
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