WO2021186781A1

WO2021186781A1 - Capacity recovery device, capacity recovery method, and secondary battery system

Info

Publication number: WO2021186781A1
Application number: PCT/JP2020/039621
Authority: WO
Inventors: 渉太伊藤; 杉政　昌俊; 耕平本蔵; 誠之廣岡; 栄二關; 純川治
Original assignee: 株式会社日立ハイテク
Priority date: 2020-03-16
Filing date: 2020-10-21
Publication date: 2021-09-23
Also published as: JP2021150028A

Abstract

Provided is a capacity recovery device capable of achieving a long lifespan while suppressing material degradation of a positive electrode of a secondary battery. To this end, a capacity recovery device (350) comprises: a capacity recovery current control unit (506) that recovers the capacity of a secondary battery (300) by moving reaction species from a capacity recovery electrode to a positive electrode or a negative electrode, the secondary battery (300) including a positive electrode terminal (2) connected to the positive electrode, a negative electrode terminal (3) connected to the negative electrode, and a capacity recovery electrode terminal (4) connected to the capacity recovery electrode for moving the reactive species to the positive electrode or the negative electrode; a discharge necessity determination unit (510) that determines whether or not to perform discharge between the capacity recovery electrode terminal (4) and the positive electrode terminal (2) or the negative electrode terminal (3) after the capacity recovery current control unit (506) recovers the capacity; and a discharge control unit (508) that performs the discharge between the positive electrode (2) or the negative electrode (3) and the capacity recovery electrode terminal (4) when the determination result by the discharge necessity determination unit (510) is positive.

Description

Capacity recovery device, capacity recovery method and secondary battery system

The present invention relates to a capacity recovery device, a capacity recovery method, and a secondary battery system.

As a background technology in the present technical field, the following abstract of Patent Document 1 states, "The battery system for solving the above problems is a battery system including an assembled battery configured by connecting a plurality of lithium ion batteries. , The lithium ion battery is characterized by including a positive electrode, a negative electrode, a third electrode for adjusting the amount of lithium ions of at least one of the positive electrode and the negative electrode, and a fourth electrode serving as a reference potential. " Has been done.
Further, in the specification of Patent Document 2 below, paragraph 0080, "As described above, the present invention does not destroy the state of the charge / discharge curve of the entire positive electrode and the charge / discharge curve of the entire negative electrode inside the secondary battery. This makes it possible to identify the cause of battery deterioration in a non-destructive manner and to determine the life of the battery with high accuracy. Further, according to the present invention, the deteriorated battery can be determined by applying the result of the reproduction calculation. It is also possible to determine the appropriate range of use of the battery with high accuracy, and to obtain the amount of reduction of charge / discharge reaction species in a non-destructive manner. " The descriptions of these documents are included as part of the specification of the present application.

Japanese Unexamined Patent Publication No. 2016-091613 Japanese Patent No. 4884404

By the way, with respect to a secondary battery such as a lithium ion battery, there is a demand to realize a long life while suppressing deterioration of the material of the positive electrode.
The present invention has been made in view of the above circumstances, and provides a capacity recovery device, a capacity recovery method, and a secondary battery system capable of achieving a long life while suppressing material deterioration of the positive electrode of the secondary battery. The purpose.

In order to solve the above problems, the capacity recovery device of the present invention is a capacity recovery device connected to a positive electrode terminal connected to a positive electrode, a negative electrode terminal connected to a negative electrode, and a capacity recovery electrode for moving a reaction species to the positive electrode or the negative electrode. A capacity recovery device for a secondary battery including a pole terminal, which is a capacity recovery current control unit that recovers the capacity of the secondary battery by moving the reaction species from the capacity recovery electrode to the positive electrode or the negative electrode. After the capacitance recovery current control unit recovers the capacitance, a discharge necessity determination unit that determines whether or not to discharge between the capacitance recovery electrode terminal and the positive electrode terminal or the negative electrode terminal, and the discharge necessity determination unit. It is characterized by including a discharge control unit that discharges between the positive electrode terminal or the negative electrode terminal and the capacitance recovery electrode terminal when the determination result in the discharge necessity determination unit is affirmative.

According to the present invention, it is possible to achieve a long life while suppressing material deterioration of the positive electrode of the secondary battery.

FIG. 5 is a cross-sectional view showing an example of a cell applied to a preferred first embodiment. It is sectional drawing which conceptually shows the power generation element of the cell in FIG. It is a circuit diagram which shows an example of the charge / discharge apparatus applied to this embodiment. It is a circuit diagram of a charge / discharge device according to a modification. It is a graph which shows an example of the open circuit potential curve of a positive electrode. It is a flowchart of the 1st detection mode processing routine. It is a figure which shows the battery discharge curve, the positive electrode discharge curve and the negative electrode discharge curve. It is a flowchart of the 2nd detection mode processing routine. It is a figure which shows the relationship between the utilization rate of a positive electrode, and the electric energy rate of energization. It is a graph which shows an example of the capacity recovery rate with respect to the energization electric quantity rate.

[Premise of Embodiment]
Lithium-ion batteries are a type of 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. In a lithium ion battery, a lithium metal oxide is generally used as the active material of the positive electrode, and a carbon material such as graphite is generally used as the active material of the negative electrode. The positive electrode and the negative electrode of a 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.

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, 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. do.

Among these factors, for the capacity decrease due to (3) described 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. However, if the lithium ions are excessively replenished, the concentration of lithium ions in the positive electrode active material becomes excessive at the time of discharge, which causes a problem of promoting material deterioration of the positive electrode. In such a case, the capacity may be reduced due to the deterioration of the material of the positive electrode.

Therefore, by applying the technique shown in Patent Document 1, a third electrode for adjusting the amount of lithium ions of at least one of the positive electrode and the negative electrode is provided, and lithium ions are supplied from the third electrode to the positive electrode or the negative electrode. Can be considered. However, when lithium ions are excessively replenished from the third electrode to the anode, material deterioration may occur in the positive electrode. Therefore, a preferred embodiment described later is to suppress material deterioration of the positive electrode.

[First Embodiment]
<Structure of cell 100>
FIG. 1 is a cross-sectional view showing an example of a cell 100 applied to a preferred first embodiment.
In FIG. 1, the cell 100 is a cell of a lithium ion battery, and includes a power generation element 1, a positive electrode terminal 2, a negative electrode terminal 3, a capacity recovery electrode terminal 4, and an exterior material 6. The power generation element 1 includes a separator 5. 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 in FIG.
In FIG. 2, the power generation element 1 includes a plurality of separators 5, a plurality of positive electrodes 12, a plurality of negative electrodes 13, and a pair of capacitance recovery electrodes 14. The positive electrode 12 and the negative electrode 13 are alternately arranged with the separator 5 interposed therebetween. The capacitance recovery electrode 14 is arranged on the outermost side as an electrode, and a separator 5 is also arranged on the outside of the capacitance recovery electrode 14. The separator 5 is not particularly limited, but polypropylene or the like is used, for example. In addition to polypropylene, a microporous film made of polyolefin such as polyethylene, a non-woven fabric, or the like can be used as the separator 5.

The positive electrode 12, the negative electrode 13, and the capacity recovery electrode 14 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 collecting foil of the positive electrode 12 and the capacity recovery electrode 14 is an aluminum foil having a thickness of 10 to 100 μm, an aluminum perforated foil having a thickness of 10 to 100 μm and a pore diameter of 0.1 to 10 mm, an expanded metal, a foamed metal plate, or the like. Is used. As the material of the current collector foil, stainless steel, titanium and the like can be applied in addition to aluminum. The material, shape, manufacturing method, etc. of the current collector foil are not particularly limited, and any current collector can be used. The electrode active material of the positive electrode 12 and the capacity recovery electrode 14 preferably contains a reaction species inside.

The reactive species of lithium-ion batteries is lithium-ion. In this case, the lithium ion battery contains a lithium-containing compound capable of reversibly inserting and removing lithium ions. The type of electrode active material of the positive electrode 12 and the capacity recovery electrode 14 is not particularly limited, but for example, phosphoric acid transitions such as lithium cobalt oxide, manganese-substituted lithium cobalt oxide, lithium manganate, lithium nickel oxide, and olivine-type lithium iron phosphate. metallic lithium, (wherein, w, x, y, z is 0 or a positive _{_{_{value) Li w Ni x Co y Mn}}} z O 2 and the like. As the electrode active material of the positive electrode 12 and the capacity recovery electrode 14, the above materials may be contained alone or in combination of two or more. Further, the same configuration may be applied to the positive electrode 12 and the capacity recovery electrode 14. As described above, by applying the same configuration to the positive electrode 12 and the capacity recovery electrode 14, the manufacturing cost can be reduced.

Further, as the current collecting foil of the negative electrode 13, a copper foil having a thickness of 10 to 100 μm, a copper perforated foil having a thickness of 10 to 100 μm and a pore diameter of 0.1 to 10 mm, an expanded metal, a foamed metal plate, or the like is used. However, as the material of the negative electrode 13, stainless steel, titanium and the like can be applied in addition to copper, and any current collector can be used without being limited by the material, shape, manufacturing method and the like. The electrode active material of the negative electrode 13 contains a substance capable of reversibly inserting and removing lithium ions. The type of the electrode active material of the negative electrode 13 is not particularly limited, but for example, natural graphite, a composite carbonaceous material in which a film is formed on natural graphite by a dry CVD method or a wet spray method, a resin material such as epoxy or phenol, or a resin material such as epoxy or phenol or Artificial graphite, silicon (Si), graphite mixed with silicon, non-graphitized carbon material, lithium titanate, Li ₄ Ti ₅ O _12, etc., which are produced by firing using pitch-based materials obtained from petroleum or coal as raw materials, are used. be able to. The above materials may be contained alone or in combination of two or more as the negative electrode active material.

The power generation element 1 is impregnated with an electrolytic solution. The electrolytic solution is not particularly limited, but in the case of a lithium ion battery, for example, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC). ), Methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC) and other aproton organic solvents can be applied.

In addition, as the electrolytic solution, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium iodide, and lithium chloride are added to the solvent of two or more mixed organic compounds among these aprotonic organic solvents. Lithium, lithium bromide, LiB [OCOCF ₃ ] ₄ , LiB [OCOCF ₂ CF ₃ ] ₄ , LiPF ₄ (CF ₃ ) ₂ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ CF ₂ CF ₃ ) _2, etc. Or an electrolytic solution in which two or more of these mixed lithium salts are dissolved can be applied.

Alternatively, a solid electrolyte may be applied instead of the electrolytic solution. The solid electrolyte is not particularly limited, and examples thereof include ionic conductive polymers such as polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, polyhexafluoropropylene, and polyethylene oxide. When these solid polymer electrolytes are used, the separator 5 can be omitted.

A metal tab (not shown) is connected to the current collecting foils of the positive electrode 12, the negative electrode 13, and the capacity recovery electrode 14. Then, the exterior material 6 is sealed so that only these tab portions are exposed to the outside of the exterior material 6 (see FIG. 1) such as a laminated film. Then, what the tabs are connected to is the positive electrode terminal 2, the negative electrode terminal 3, and the capacitance recovery electrode terminal 4 shown in FIG. The power generation element 1 is manufactured by facing the positive electrode 12 and the negative electrode 13 via the separator 5 and winding or laminating them. When the power generation element 1 is configured by winding, the capacity recovery electrode 14 may be arranged near the winding axis (central axis) of the winding body or at the outermost peripheral portion. Further, when the power generation element 1 is configured by stacking, the capacity recovery pole 14 may be arranged as a part of the laminated body.

<Charging / discharging

device

350, 370>
FIG. 3 is a circuit diagram showing an example of a charging / discharging device 350 (capacity recovery device, secondary battery system) applied to the present embodiment.
In FIG. 3, the battery pack 300 (secondary battery, secondary battery system) includes the cell 100 shown in FIG. 1, a protection circuit (not shown), a housing, and the like, and includes a positive electrode terminal 2 and a negative electrode. The terminal 3 and the capacity recovery electrode terminal 4 are projected. However, the battery pack 300 may include a plurality of cells 100. Further, the battery pack 300 may be configured to include a plurality of battery modules (not shown) including a plurality of cells 100. 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 charging / discharging device 350 includes an ammeter 351, a voltmeter 352, 359, a resistor 353, a power supply 354, a charge / discharge changeover switch 356, a capacity recovery switch 357, a positive / negative electrode changeover switch 358, and a control unit 500. , Is equipped. Of these, each of the

switches

356, 357, and 358 has three terminals (unsigned) and switches the connection state between the three terminals. However, these

switches

356, 357, and 358 can be set so that none of the three terminals is connected to each other.

The voltmeter 352 measures the voltage between the positive electrode terminal 2 and the negative electrode terminal 3, and the voltmeter 359 measures the voltage between the negative electrode terminal 3 and the capacitance recovery electrode terminal 4. The control unit 500 calculates the voltage between the positive electrode terminal 2 and the capacitance recovery electrode terminal 4 by adding or subtracting the measurement results of the voltmeters 352 and 359. The capacity recovery switch 357 and the charge / discharge changeover switch 356 have either the negative electrode terminal 3 or the capacity recovery electrode terminal 4 of the battery pack 300, and either the resistor 353 or the power supply 354, based on the control by the control unit 500. Connecting. The positive / negative electrode changeover switch 358 connects either the positive electrode terminal 2 or the negative electrode terminal 3 to one end of the ammeter 351 based on the control by the control unit 500. The other end of the ammeter 351 is connected to the resistor 353 and the power supply 354. The voltmeter 352,359 and the ammeter 351 supply the measurement result to the control unit 500.

However, when the positive / negative electrode changeover switch 358 selects the negative electrode terminal 3, the control unit 500 makes the capacitance recovery switch 357 always select the capacitance recovery electrode terminal 4. The configuration of the charging / discharging device 350 is not limited to that shown in FIG. 3, and any two terminals selected from the positive electrode terminal 2, the negative electrode terminal 3, and the capacity recovery electrode terminal 4 of the battery pack 300 are not limited to those shown in FIG. Any circuit can be used as long as it can be connected to the resistor 353, the power supply 354, and the like.

FIG. 4 is a circuit diagram of the charging / discharging device 370, which is a modification of the charging / discharging device 350.
In FIG. 4, the positive / negative electrode changeover switch 358 in FIG. 3 is omitted, and the negative electrode terminal 3 of the battery pack 300 and the ammeter 351 are directly connected. Further, the capacity recovery switch 357 and the charge / discharge changeover switch 356 in FIG. 4 are controlled by the control unit 500 with either the positive electrode terminal 2 or the capacity recovery electrode terminal 4 of the battery pack 300, and the resistor 353 or the power supply 354. Connect with any of. The configuration of the charging / discharging device 370 other than the above is the same as that of the charging / discharging device 350 (see FIG. 3), and according to the configuration shown in FIG. 4, the circuit configuration and control can be made simpler.

<Control unit 500>
In FIG. 3, the control unit 500 includes hardware as a general computer such as a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The control program to be executed and various data are stored. In FIG. 3, the inside of the control unit 500 shows a function realized by a control program or the like as a block.

That is, the control unit 500 includes an energization electric energy determination unit 502, a capacity recovery pole selection unit 504, a capacity recovery current control unit 506 (capacity recovery process), a discharge control unit 508 (discharge control process), and discharge necessity. It includes a determination unit 510 (discharging necessity determination process). Then, the discharge necessity determination unit 510 includes a detection mode selection unit 512, a determination potential calculation unit 514, an open circuit potential measurement unit 516, a potential comparison unit 518, a characteristic analysis unit 520, and a potential / discharge amount calculation unit. 522 and a discharge amount comparison unit 524 are provided.

The energizing electricity amount determining unit 502 determines the timing of capacitance recovery and the energizing electricity amount from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or the negative electrode terminal 3 based on the inputs from the ammeter 351 and the voltmeter 352 and 359. do. The capacity recovery pole selection unit 504 causes the capacity recovery switch 357 to select the capacity recovery switch 357. As a result, the capacitance recovery electrode terminal 4 is connected to the positive electrode terminal 2 or the negative electrode terminal 3.

The capacity recovery current control unit 506 causes the charge / discharge changeover switch 356 to select the resistor 353 or the power supply 354 according to the desired capacity recovery current. As a result, the current flowing between the capacitance recovery electrode terminal 4 and the positive electrode terminal 2 or the negative electrode terminal 3 becomes a value according to the selection result in the charge / discharge changeover switch 356. For example, when the potential of the capacitance recovery electrode terminal 4 is lower than the potential of the positive electrode terminal 2 or the negative electrode terminal 3, the capacitance is recovered from the positive electrode terminal 2 or the negative electrode terminal 3 by selecting the resistor 353 with the charge / discharge changeover switch 356. A current can be passed through the electrode terminal 4.

Further, the capacitance recovery current control unit 506 calculates the amount of electricity flowing between the capacitance recovery electrode terminal 4 and the positive electrode terminal 2 or the negative electrode terminal 3 based on the output of the ammeter 351. Then, when the calculated electric energy reaches a predetermined target value, the capacity recovery current control unit 506 operates the capacity recovery switch 357 and the charge / discharge changeover switch 356 to operate the capacity recovery pole terminal 4 and the positive electrode terminal 2 or The current between the negative electrode terminal 3 and the negative electrode terminal 3 is cut off.

The discharge necessity determination unit 510 determines whether or not discharge should be performed between the capacitance recovery electrode terminal 4 and the positive electrode terminal 2 or the negative electrode terminal 3 after the capacitance recovery current control unit 506 operates. That is, the discharge necessity determination unit 510 detects whether or not "use of the low potential region" (details will be described later) has occurred in the battery pack 300, and if it has occurred, "discharges". To that effect. When the discharge necessity determination unit 510 determines that the discharge necessity determination unit 510 "discharges", the discharge control unit 508 switches the positive / negative electrode changeover switch so that a current flows between the capacitance recovery electrode terminal 4 and the positive electrode terminal 2 or the negative electrode terminal 3. It controls 358 and the capacity recovery switch 357. When a current is passed between the capacity recovery electrode terminal 4 and the positive electrode terminal 2, the battery pack 300 is discharged to the discharge lower limit voltage in advance.

Further, the discharge control unit 508 causes the charge / discharge changeover switch 356 to select either the resistor 353 or the power supply 354. Here, when the resistor 353 is selected, a current spontaneously flows from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or the negative electrode terminal 3 due to the potential difference between the capacitance recovery electrode terminal 4 and the positive electrode terminal 2 or the negative electrode terminal 3, so that it is external. Eliminates the need to use electricity. On the other hand, when the power supply 354 is selected by the charge / discharge changeover switch 356, the current flowing through the power supply 354 can be controlled according to the voltage of the power supply 354. It is possible to prevent a large current from flowing.

The detection mode selection unit 512 selects either the first detection mode or the second detection mode based on a command from the user or the like. This detection mode is a detection mode for detecting the above-mentioned "use of low potential region". That is, the first detection mode is a mode for determining "use of the low potential region" based on the open circuit potential of the positive electrode terminal 2, and the second detection mode is the "low potential region" from the charge / discharge curve of the battery pack 300. This is the mode for determining "use of". The user or the like may select the detection mode on the preferred side according to the type and characteristics of the battery pack 300.

FIG. 5 is a graph for conceptually explaining the open circuit potential curve C2 of the positive electrode terminal 2 and the detection method of "use of the low potential region" of the positive electrode terminal 2.
The horizontal axis of FIG. 5 represents the discharge capacity, and the vertical axis is the open circuit potential V _OCV of the positive electrode terminal 2 with the potential of the capacity recovery electrode terminal 4 as a reference potential. _{The determination potential V OCV0} shown by the broken line in the figure is a potential indicating the boundary of the low potential region. When the first detection mode is selected, the open-circuit potential measuring unit 516 measures V _OCV when the battery is inactive in an arbitrary charging state.

Potential comparison unit 518, and determines if V _OCV than the determination voltage V _OCV0 low, "Use of the low potential region" occurs. As a result, as described above, the discharge control unit 508 connects the capacitance recovery electrode terminal 4 and the positive electrode terminal 2 or the negative electrode terminal 3 via the resistor 353 or the power supply 354, and connects the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or A current is passed through the negative electrode terminal 3. The timing at which the open-circuit potential measuring unit 516 measures the open-circuit potential V _OCV is not particularly limited, but it is preferably 5 minutes or later from the start of pause, and more preferably 30 minutes or later from the start of pause. As described above, after 5 minutes or 30 minutes have passed from the start of the pause, the polarization of the positive electrode potential due to charging / discharging of the battery pack 300 is eliminated, so that the equilibrium potential of the positive electrode can be measured more accurately.

The equilibrium potential of the capacitance recovery electrode terminal 4 changes depending on the amount of the reaction species extracted from the capacitance recovery electrode terminal 4. Therefore, returning to FIG. 3, the determination potential calculation unit 514 calculates and stores _{the determination potential V OCV0 described above.} That is, the determination potential calculation unit 514 stores the integrated current value of the current flowing through the capacitance recovery pole terminal 4. Then, the determination potential calculation unit 514 determines the determination potential V by the amount of change in the equilibrium potential each time a current is passed through the capacitance recovery electrode terminal 4 based on the relationship between the charge amount and the equilibrium potential of the capacitance recovery electrode terminal 4 created in advance. _{Change OCV0} . In other words, when a predetermined amount of electric current flows from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or the negative electrode terminal 3, the determination potential calculation unit 514 updates the _{stored V OCV 0.} Further, the potential comparison unit 518 compares the updated determination potential V _OCV0 and V _OCV again, and determines whether or not “the use of the low potential region” is present.

_{The operation of passing a} current from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or the negative electrode terminal 3 may be continued until the open circuit potential V OCV becomes higher than the determination potential V _{OCV 0.} Further, if the determination potential V _OCV0 is set to a potential slightly higher than the discharge end, that is, _{a potential before the open circuit potential V OCV} rapidly decreases, over-discharging of the positive electrode terminal 2 can be avoided. As a result, it is possible to avoid using the low potential region of the positive electrode terminal 2 after the capacity of the battery pack 300 is restored, and it is possible to suppress deterioration of the positive electrode material.

Here, the determination potential V _OCV0 is set to a potential corresponding to the SOC (state of charge) in the range of 0 to 10% based on the open circuit potential curve (FIG. 5) of the positive electrode terminal 2. Is preferable, and it is more preferable to set the potential to correspond within the range of 0 to 5%. Here, SOC represents the charge ratio with respect to the total capacity of the positive electrode. Frequent detection of the use of the low potential region of the positive electrode can interfere with the normal operation of the battery. However, if the determination potential V _OCV0 is set as described above, the frequency of interfering with normal operation can be reduced.

FIG. 6 is a flowchart of the first detection mode processing routine executed by the control unit 500 in the first detection mode.
In FIG. 6, in step S110, the capacity of the battery pack 300 is recovered by the energization electric energy determination unit 502 of the control unit 500 (see FIG. 1), the capacity recovery pole selection unit 504, and the capacity recovery current control unit 506. The process is executed. That is, the capacity recovery electrode terminal 4 and, for example, the positive electrode terminal 2 are connected via a resistor 353 or a power supply 354, whereby the capacity of the battery pack 300 is recovered.

When the capacity recovery process in step S110 is completed, the open circuit potential measurement process in step S120 and the determination potential update process in step S130 are executed in parallel. First, in step S120, the open circuit potential measuring unit 516 measures the open circuit potential V _OCV of the positive electrode terminal 2 with respect to the capacitance recovery electrode terminal 4. Further, in step S130, the determination potential calculation unit 514 updates the _{stored determination potential V OCV 0} based on the integrated current value of the current that has flowed to the capacitance recovery pole terminal 4 in the past.

Next, in step S140, the potential comparing unit 518 calculates a difference value between the open circuit potential V _OCV and determination potential _{_{_{V OCV0 (V OCV -V OCV0)}}} . Next, in step S150, the potential comparison unit 518 _{determines whether or not the difference value (V OCV −} V _OCV0 ) is a negative value.

When it is determined in step S150 that “NO” (that is, V _OCV ≧ _{V OCV 0} ), the potential comparison unit 518 “does not discharge” in step S170, that is, “from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or the negative electrode terminal”. It is decided that "no current is passed through 3". On the other hand, if “YES” (that is, V _OCV <V _OCV0 ) is determined in step S150, the potential comparison unit 518 “discharges” in step S160, that is, “from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or the negative electrode”. It is determined that "current is passed through the terminal 3". As a result, the discharge control unit 508 controls the positive / negative electrode changeover switch 358 and the capacitance recovery switch 357 so that a current flows between the capacitance recovery electrode terminal 4 and the positive electrode terminal 2 or the negative electrode terminal 3.

In the period between step S110 and step S120 or S130, the battery pack 300 may be charged or discharged as a normal battery. As described above, according to the first detection mode, it is possible to determine whether or not the low potential region of the positive electrode is used when the battery pack 300 is paused without performing special charging / discharging of the battery pack 300. In particular, when the battery pack 300 is in a state close to a completely discharged state, the use of the low potential region in the positive electrode can be accurately detected.

When the second detection mode is selected by the detection mode selection unit 512, the characteristic analysis unit 520, the potential / discharge amount calculation unit 522, and the discharge amount comparison unit 524 have a low positive electrode based on the charge / discharge curve. Determine the use of the potential region. At this time, the voltage of the charge / discharge curve is preferably a value close to the open circuit voltage. The energization method when calculating the charge / discharge curve data is arbitrary. For example, 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 can be adopted with a minute and constant current. Further, a method may be adopted in which a cycle of discharging with a constant current for a certain period of time and then resting for a certain period of time is repeated from a fully charged state to a fully discharged state. Further, a method may be adopted in which a cycle of charging with a constant current for a certain period of time and then resting for a certain period of time is repeated from a fully discharged state to 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 calculated. The method of estimating the relationship between the two may be adopted. Further, in the various methods described above, "discharging from a fully charged state to a fully discharged state", "charging from a fully discharged state to a fully charged state", etc. have been described, but it is not always the case that the battery is discharged or charged within these ranges. It is not limited. The range of charge / discharge is preferably wide, and most preferably 100%. However, if the subsequent steps can be smoothly performed, charging / discharging may be performed in a range of 50% or more of the range from the fully charged state to the fully discharged state. Further, if possible, charging / discharging may be performed in a range of less than 50% of the range from the fully charged state to the fully discharged state.

FIG. 7 is a diagram showing a battery discharge curve C4, a positive electrode discharge curve C6, and a negative electrode discharge curve C8. The origin on the horizontal axis means the fully charged state of the battery.
The battery discharge curve C4 is a discharge curve of the battery pack 300, which is a lithium ion battery. Further, the positive electrode discharge curve C6 is a discharge curve of the positive electrode potential, that is, the potential of the positive electrode terminal 2, and the negative electrode discharge curve C8 is a discharge curve of the negative electrode potential, that is, the potential of the negative electrode terminal 3. The battery discharge curve C4 can be calculated based on the output values of the ammeter 351 and the voltmeter 352 and 359. On the other hand, the positive electrode discharge curve C6 and the negative electrode discharge curve C8 are calculated values obtained by the characteristic analysis unit 520 in the regression calculation process (reproduction calculation process). In other words, the characteristic analysis unit 520 can separate the battery discharge curve C4 of the lithium ion battery into a positive electrode discharge curve C6 and a negative electrode discharge curve C8 by analyzing the battery discharge curve C4. Such a method of reproduction calculation processing is described in detail in Patent Document 2 described above.

The outline of the contents will be described below. First, the characteristic analysis unit 520
First, as correction parameters, the positive electrode active material amount m _p , the negative electrode active material amount m _n _{, the index C p} of the positional relationship of _{the positive electrode discharge curve, and the index C n} of the positional relationship of the negative electrode discharge curve are obtained. ,Remember. Next, characteristic analysis unit 520 multiplies the amount of the positive electrode active material m _p in the discharge amount of the positive electrode 11, multiplied by the amount of the positive electrode active material m _p in the discharge amount of the negative electrode 13, the reference of the positive electrode 11 (see FIG. 2) Based on the mass and the reference mass of the negative electrode 13 (see FIG. 2), the calculated values of the positive electrode discharge curve and the negative electrode discharge curve are obtained.

These calculated values are referred to as a positive electrode discharge curve calculated value C6'and a negative electrode discharge curve calculated value C8'(not shown). Further, the difference between these calculated values C6'and C8' is defined as the battery discharge curve calculated value C4'. The characteristic analysis unit 520 adjusts the _{correction parameters m p} , m _n , C _p , and C _n so that the calculated battery discharge curve value C4'approaches the battery discharge curve C4 (preferably so that they match). Then, the positive electrode discharge curve calculated value C6'and the negative electrode discharge curve calculated value C8'are calculated and updated again based on the adjusted correction parameters m _p , m _n , C _p , and C _n. The results are the positive electrode discharge curve C6 and the negative electrode discharge curve C8 shown in FIG.

Returning to FIG. 3, the potential / discharge amount calculation unit 522 calculates the discharge amount corresponding to the predetermined charging state. In other words, the potential / discharge amount calculation unit 522 calculates the discharge amount corresponding to each of the positive electrode potential and the negative electrode potential corresponding to a predetermined charging state. Here, the discharge amount means the capacity that the positive electrode or the negative electrode can discharge from the fully charged state of the battery, and is represented by the value on the horizontal axis in FIG. 7. _{In FIG. 7, assuming} that the positive electrode potential in the “predetermined charging state” is V p0 (first potential), the discharge amount Q _p0 _{(first discharge amount) corresponding to this positive electrode potential V p0} is the positive electrode discharge curve. Obtained from C6. _{Further, assuming} that the negative electrode potential in the above "predetermined charging state" is V n0 (second potential), the discharge amount Q _n0 _{(second discharge amount) corresponding to this negative electrode potential V n0} is the negative electrode discharge curve C8. Obtained from. Then, the discharge amount comparison unit 524 determines that "discharge is performed" when _{the difference value (Q n0} −Q _{p0) between the two is positive.}

When the discharge amount comparison unit 524 determines that "discharging is performed", the discharge control unit 508 causes a current to flow from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or the negative electrode terminal 3. At that time, the amount of electricity flowing from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or the negative electrode terminal 3 is set to a value of _{"Q n0-} Q _{p0" or more.} More preferably, _{the amount of electricity required for the reaction species corresponding to (Q n0} −Q _p0 ) to move from the positive electrode 12 or the negative electrode 13 to the capacitance recovery electrode 14 is transferred from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2. Alternatively, it may flow to the negative electrode terminal 3.

As a result, after the current is passed from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or the negative electrode terminal 3, the negative electrode potential reaches _{V n0} _{when the positive electrode potential is V p0.} Therefore, it is preferable to set the negative electrode potential V _n0 to the potential at the discharge end, for example, 0.2 V to 1.0 V based on the lithium metal. _{Alternatively, instead of this, the negative electrode potential V n0} may be set to a potential corresponding to the range in which the charging ratio to the total capacity of the negative electrode is in the range of 0 to 5%, based on the open circuit potential curve of the negative electrode terminal 3. In any case, the negative electrode potential V _n0 may be set at a position where the negative electrode discharge curve C8 rapidly rises. As a result, the negative electrode potential at the end of battery discharge becomes a value close to _{V n0.} Therefore, the positive electrode potential at that time is V _p0 . That is, since the open circuit potential of the positive electrode does not become _{V p0} _{or less when the battery is discharged, if the positive electrode potential V p0} is set to the potential before the positive electrode discharge curve C6 rapidly decreases, over-discharging of the positive electrode can be avoided. can. V _p0 is, for example, 3.4 V to 3.6 V based on the lithium metal, or a potential corresponding to the range where the charge ratio to the total capacity of the positive electrode is in the range of 0 to 10% based on the open circuit potential curve of the positive electrode terminal 2. It is preferable to set it, and it is more preferable to set it to the corresponding potential within the range of 0 to 5%. As a result, the use of the low potential region of the positive electrode can be avoided after the capacity is restored, and the material deterioration of the positive electrode can be suppressed.

FIG. 8 is a flowchart of the second detection mode processing routine executed by the control unit 500 in the second detection mode.
In FIG. 8, in step S210, the capacity of the battery pack 300 is recovered by the energization electric energy determination unit 502 of the control unit 500 (see FIG. 1), the capacity recovery pole selection unit 504, and the capacity recovery current control unit 506. The process is executed. That is, the reaction species is supplied from the capacity recovery electrode 14 (see FIG. 2) to the positive electrode 12 or the negative electrode 13.

Next, in step S220, the characteristic analysis unit 520 acquires the positive electrode discharge curve C6 and the negative electrode discharge curve C8 from the battery discharge curve C4. That is, the battery discharge curve C4 is separated into a positive electrode discharge curve C6 and a negative electrode discharge curve C8 by the reproduction calculation process. _{Next, in step S230, the potential / discharge amount calculation unit 522 calculates the discharge amounts Q p0} and Q _n0 corresponding to the “predetermined charging state” for each of the positive electrode terminal 2 and the negative electrode terminal 3.

Next, in step S240, the discharge amount comparison unit 524 calculates the difference value (Q _n0 −Q _p0 ) between the _{discharge amounts Q p0} and Q _n0. Next, in step S250, the discharge amount comparison unit 524 _{determines whether or not the difference value (Q n0} −Q _p0 ) is a positive value.

When it is determined in step S250 that "NO" (that is, Q _n0 ≤ Q _p0 ), the discharge amount comparison unit 524 "does not discharge" in step S270, that is, "from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or the negative electrode". It is determined that no current is passed through the terminal 3. On the other hand, if it is determined in step S250 that "YES" (that is, Q _n0 > Q _p0 ), the discharge amount comparison unit 524 "discharges" in step S260, that is, "from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or It is determined that a current is passed through the negative electrode terminal 3. As a result, the discharge control unit 508 controls the positive / negative electrode changeover switch 358 and the capacitance recovery switch 357 so that a current flows between the capacitance recovery electrode terminal 4 and the positive electrode terminal 2 or the negative electrode terminal 3.

In the period between step S210 and step S220, the battery pack 300 may be arbitrarily charged and discharged as a normal battery. The battery discharge curve C4, the positive electrode discharge curve C6, and the negative electrode discharge curve C8 applied in the above example were all "discharge curves", but instead of these, the corresponding "charge curve", that is, the battery charge curve, A positive electrode charging curve and a negative electrode charging curve (not shown) may be applied.

As described above, according to the second detection mode, the battery discharge curve C4 of the battery pack 300 is analyzed to estimate the positive electrode discharge curve C6 and the negative electrode discharge curve C8, and the predetermined positive electrode potential V _p0 and the predetermined negative electrode potential V _A current can be passed from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or the negative electrode terminal 3 so as to coincide with n0. Therefore, according to the second detection mode, the amount of electricity flowing from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or the negative electrode terminal 3 can be calculated, and the discharge control unit 508 can be operated according to the calculation result. As a result, for example, it is possible to suppress the possibility that the current is excessively discharged and the recovery effect of the recovery process is unnecessarily reduced.

Hereinafter, application examples of this embodiment will be described.
FIG. 9 is a diagram showing the relationship between the utilization rate of the positive electrode and the energization electric energy rate. That is, FIG. 9 shows the utilization rate of the positive electrode immediately after the recovery process after the capacity recovery process of the battery pack 300 is performed and the battery pack 300 is charged and discharged for 600 cycles at a current density of 1CA in an environment of 50 ° C. with respect to the energized electric energy rate. This is an example of the plotted results. The positive electrode utilization rate on the vertical axis is an index indicating deterioration of the positive electrode material, and the lower the value, the more the deterioration has progressed. The energizing electric energy ratio is the ratio of the electric energy flowing from the positive electrode or the negative electrode to the capacity recovery electrode with respect to the capacity of the battery.

When the charge / discharge cycle is performed after the capacity recovery process, the positive electrode utilization rate is lower than when the capacity is not recovered, and the rate of decrease tends to increase as the energization electric energy rate increases. This is because the material deterioration of the positive electrode was promoted by the charge / discharge cycle using the low potential region of the positive electrode due to the excessive recovery.

FIG. 10 is a graph showing an example of the capacity recovery rate with respect to the energization electric energy rate. The capacity recovery rate is the ratio of the recovered capacity to the initial capacity of the battery. The capacity recovery rate tends to increase as the energization electric energy rate increases, but tends to reach a plateau. _{This corresponds to the fact that the difference value (Q n0} −Q _p0 ) of the capacitance between the positive electrode and the negative electrode shown in FIG. 7 becomes a positive value, that is, the excessive capacitance recovery treatment is performed.
In the examples of FIGS. 9 and 10, when the energization electricity amount rate is about 30 to 40%, a high capacity recovery rate (capacity recovery effect) can be obtained while suppressing a decrease in the utilization rate of the positive electrode (material deterioration of the positive electrode). Can be done. If the energization electric energy ratio exceeds about 40% in the examples of FIGS. 9 and 10, by passing a current from the capacitance recovery electrode to the positive electrode or the negative electrode in order to detect the use of the low potential region of the positive electrode. , The energizing electric energy rate can be lowered. That is, according to this embodiment, it is possible to obtain a high capacity recovery effect while suppressing material deterioration of the positive electrode.

[Effect of Embodiment]
According to the preferred embodiment as described above, the capacity recovery device (350) moves the reaction species to the positive electrode terminal 2 connected to the positive electrode 12, the negative electrode terminal 3 connected to the negative electrode 13, and the positive electrode 12 or the negative electrode 13. By moving the reaction species from the capacity recovery electrode 14 to the positive electrode 12 or the negative electrode 13 of the secondary battery (300) including the capacity recovery electrode terminal 4 connected to the capacity recovery electrode 14, the secondary battery (300) Whether or not to discharge between the capacity recovery electrode terminal 4 and the positive electrode terminal 2 or the negative electrode terminal 3 after the capacity recovery current control unit 506 that recovers the capacity and the capacity recovery current control unit 506 recovers the capacity. Discharge control unit 508 that discharges between the positive electrode terminal 2 or the negative electrode terminal 3 and the capacitance recovery electrode terminal 4 when the determination result in the discharge necessity determination unit 510 and the discharge necessity determination unit 510 for determination is affirmative. And. As a result, discharge can be performed between the positive electrode terminal 2 or the negative electrode terminal 3 and the capacity recovery electrode terminal 4, and a long life can be realized while suppressing material deterioration of the positive electrode 12 of the secondary battery (300).

Further, the discharge necessity determination unit 510 determines the determination potential _{from the open circuit potential measuring unit 516 that measures the open circuit potential V OCV} of the positive electrode terminal 2 with respect to the capacitance recovery electrode terminal 4 and the integrated electric potential that flows through the capacitance recovery electrode terminal 4. and determining the potential calculating unit 514 for calculating a V _OCV0, the potential comparing unit 518 that a positive determination result when the open circuit potential V _OCV is less than the determination potential V _OCV0, be provided with a more preferred. Thereby, it is possible to determine whether or not the low potential region of the positive electrode is used when the secondary battery (300) is inactive without performing special charging / discharging of the secondary battery (300).

Further, the discharge necessity determination unit 510 determines the positive electrode charge curve or the positive electrode discharge curve C6 and the negative electrode charge curve or the negative electrode discharge curve C8 based on the battery charge curve or the battery discharge curve C4 of the secondary battery (300). The desired characteristic analysis unit 520, a predetermined first potential V _{p0 at} the positive electrode terminal 2, a first discharge amount Q _p0 corresponding to the first potential V _p0 , and a predetermined second potential V at the negative electrode terminal 3. _The potential / discharge amount calculation unit 522 that calculates _n0 and the second discharge amount Q n0 corresponding to the second potential V _n0 , and the first discharge amount Q _p0 is subtracted _{from the second discharge amount Q n0.} It is provided with a discharge amount comparison unit 524 that affirms the determination result when the difference value (Q _n0 −Q _p0 _{) is a positive value, and the first potential V p0} is 3.4 V to 3 based on the lithium metal standard. It is a potential corresponding to the range of 0 to 10% of the charge ratio with respect to the total capacity of the positive electrode 12 obtained at .6 V or based on the open circuit potential curve C of the positive electrode terminal 2, and the second potential V _n0 is 0.2V to 1.0V based on the lithium metal, or at the potential corresponding to the charging ratio of the negative electrode 13 to the total capacity of 0 to 5%, which is obtained based on the open circuit potential curve of the negative electrode terminal 3. It is more preferable to have. By providing the discharge amount comparison unit 524, the amount of electricity flowing from the capacitance recovery electrode terminal 4 to the positive electrode terminal 2 or the negative electrode terminal 3 can be calculated as a _{difference value (Q n0} −Q _p0). As a result, for example, it is possible to suppress the possibility that the current is excessively discharged and the recovery effect of the recovery process is unnecessarily reduced.

Further, it is more preferable that the discharge control unit 508 _{moves the reaction species in an amount corresponding to the difference value (Q n0} −Q _p0 ) or more from the positive electrode 12 or the negative electrode 13 to the capacitance recovery electrode 14. As a result, it is possible to more reliably achieve a longer life while suppressing material deterioration of the positive electrode 12 of the secondary battery (300).

[Modification example]
The present invention is not limited to the above-described embodiment, and various modifications are possible, and other embodiments that can be considered within the scope of the technical idea of the present invention are also described as long as the features of the present invention are not impaired. Included within the scope of the invention. The above-described embodiments are exemplified for the purpose of explaining the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Further, another configuration may be added to the configuration of the above embodiment, and a part of the configuration may be replaced with another configuration. In addition, the control lines and information lines shown in the figure show what is considered necessary for explanation, and do not necessarily show all the control lines and information lines necessary for the product. In practice, it can be considered that almost all configurations are interconnected. Possible modifications to the above embodiment are, for example, as follows.

(1) In the case of the cell 100 of FIG. 1, a positive electrode, a negative electrode, and a capacity recovery electrode are built in and sealed, but the present invention can be applied to a cell that is not sealed.
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. Alternatively, the temporary seal may be temporarily sealed and stored at a high temperature and high voltage, and the temporary seal may be removed. 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.

(2) Since the hardware of the control unit 500 in the above embodiment can be realized by a general computer, the flowcharts shown in FIGS. 8 and 6 and other programs for executing the above-mentioned various processes are stored in the storage medium. Alternatively, it may be distributed via a transmission line.

(3) The processes shown in FIGS. 8 and 6 and other processes described above have been described as software-like processes using a program in the above embodiment, but some or all of them are described as ASIC (Application Specific Integrated Circuit). It may be replaced with hardware-like processing using an application specific integrated circuit) or FPGA (Field Programmable Gate Array).

2 Positive electrode terminal 3 Negative electrode terminal 4 Capacity recovery electrode terminal 12 Positive electrode 13 Negative electrode 14 Capacity recovery electrode 300 Battery pack (secondary battery, secondary battery system)
350 charge / discharge device (capacity recovery device, secondary battery system)
506 Capacity recovery current control unit (capacity recovery process)
508 Discharge control unit (discharge control process)
510 Discharge necessity determination unit (Discharge necessity determination process)
514 Judgment potential calculation unit 516 Open circuit potential measurement unit 518 Potential comparison unit 520 Characteristic analysis unit 522 Potential / discharge amount calculation unit 524 Discharge amount comparison unit C4 Battery discharge curve C6 Positive electrode discharge curve C8 Negative electrode discharge curve Q _p0 Discharge amount (1st Discharge amount)
Q _n0 discharge amount (second discharge amount)
V _p0 positive electrode potential (first potential)
V _n0 Negative potential (second potential)
V _OCV open circuit potential V _OCV0 Judgment potential Q _n0- Q _p0 Difference value

Claims

A capacity recovery device for a secondary battery including a positive electrode terminal connected to a positive electrode, a negative electrode terminal connected to a negative electrode, and a capacity recovery electrode terminal connected to a capacity recovery electrode for moving a reaction species to the positive electrode or the negative electrode. hand,
A capacity recovery current control unit that recovers the capacity of the secondary battery by moving the reaction species from the capacity recovery electrode to the positive electrode or the negative electrode.
After the capacitance recovery current control unit recovers the capacitance, a discharge necessity determination unit for determining whether or not to discharge between the capacitance recovery electrode terminal and the positive electrode terminal or the negative electrode terminal, and a discharge necessity determination unit.
A capacity recovery unit comprising a discharge control unit that discharges between the positive electrode terminal or the negative electrode terminal and the capacity recovery electrode terminal when the determination result in the discharge necessity determination unit is affirmative. Device.
The discharge necessity determination unit is
An open circuit potential measuring unit that measures the open circuit potential of the positive electrode terminal with respect to the capacitance recovery electrode terminal,
A determination potential calculation unit that calculates the determination potential from the integrated amount of electricity passed through the capacitance recovery electrode terminal,
The capacity recovery device according to claim 1, further comprising a potential comparison unit that affirms the determination result when the open circuit potential is lower than the determination potential.
The discharge necessity determination unit is
A characteristic analysis unit that obtains a positive electrode charge curve or a positive electrode discharge curve and a negative electrode charge curve or a negative electrode discharge curve based on the battery charge curve or the battery discharge curve of the secondary battery.
A predetermined first potential at the positive electrode terminal, a first discharge amount corresponding to the first potential, a predetermined second potential at the negative electrode terminal, and a second potential corresponding to the second potential. The potential / discharge amount calculation unit that calculates the discharge amount,
A discharge amount comparison unit for affirming the determination result when the difference value obtained by subtracting the first discharge amount from the second discharge amount is a positive value is provided.
The first potential is 3.4 V to 3.6 V based on the lithium metal, or a charging ratio of 0 to 10% with respect to the total capacity of the positive electrode determined based on the open circuit potential curve of the positive electrode terminal. It is the potential corresponding to the inside,
The second potential is 0.2 V to 1.0 V based on the lithium metal, or a range in which the charging ratio to the total capacity of the negative electrode is 0 to 5%, which is obtained based on the open circuit potential curve of the negative electrode terminal. The capacity recovery device according to claim 1, wherein the potential is corresponding to the inside.
The capacity recovery device according to claim 3, wherein the discharge control unit moves a reaction species in an amount corresponding to the difference value or more from the positive electrode or the negative electrode to the capacity recovery electrode.
It is a capacity recovery method of a secondary battery including a positive electrode terminal connected to a positive electrode, a negative electrode terminal connected to a negative electrode, and a capacity recovery electrode terminal connected to a capacity recovery electrode for moving a reaction species to the positive electrode or the negative electrode. hand,
A capacity recovery process for recovering the capacity of the secondary battery by moving the reaction species from the capacity recovery electrode to the positive electrode or the negative electrode.
After performing capacity recovery in the capacity recovery process, a discharge necessity determination process for determining whether or not to discharge between the capacity recovery electrode terminal and the positive electrode terminal or the negative electrode terminal, and a discharge necessity determination process.
A capacity recovery including a discharge control process for discharging between the positive electrode terminal or the negative electrode terminal and the capacity recovery electrode terminal when the determination result in the discharge necessity determination process is affirmative. Method.
A secondary battery including a positive electrode terminal connected to a positive electrode, a negative electrode terminal connected to a negative electrode, and a capacitance recovery electrode terminal connected to a capacitance recovery electrode for moving a reaction species to the positive electrode or the negative electrode.
A secondary battery system including a capacity recovery device for recovering the capacity of the secondary battery.
The capacity recovery device is
A capacity recovery current control unit that recovers the capacity of the secondary battery by moving the reaction species from the capacity recovery electrode to the positive electrode or the negative electrode.
After the capacitance recovery current control unit recovers the capacitance, a discharge necessity determination unit for determining whether or not to discharge between the capacitance recovery electrode terminal and the positive electrode terminal or the negative electrode terminal, and a discharge necessity determination unit.
A secondary feature is provided with a discharge control unit that discharges between the positive electrode terminal or the negative electrode terminal and the capacitance recovery electrode terminal when the determination result in the discharge necessity determination unit is affirmative. Battery system.