JP2012169094A - Recovery method of lithium ion battery and power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of recovering the performance of a lithium ion battery that has been deteriorated and a power supply system including recovery means of battery performance.SOLUTION: In a regeneration method of a battery, a process that raises a potential of a negative electrode above a potential of a positive electrode of a lithium ion battery that has been deteriorated, and subsequently drops the potential of the negative electrode under the potential of the positive electrode is performed at least one cycle or more. The power supply system includes means that raises a potential of a negative electrode above a potential of a positive electrode and subsequently drops the potential of the negative electrode under the potential of the positive electrode in the lithium ion battery.

Description

  The present invention relates to a power supply system equipped with a lithium ion battery.

When a lithium ion battery is stored in a high charged state at a high temperature of 50 ° C. or higher, the resistance increases. Conventionally, a countermeasure for adding a compound such as vinylene carbonate to an electrolytic solution has been proposed as a countermeasure for suppressing an increase in resistance during high-temperature storage. For example, Non-Patent Document 1 proposes a battery that can suppress deterioration during storage at 60 ° C. by adding 2 wt% of vinylene carbonate to an electrolytic solution composed of LiPF ₆ , ethylene carbonate, and dimethyl carbonate. . By adding vinylene carbonate, it is possible to suppress performance deterioration due to the growth of a film deposited on the negative electrode of the lithium ion battery, particularly output decrease due to resistance increase.

Journal of The Electrochemical Society, 151 (10) A1659-A1669 (2004)

  However, further output reduction suppression technology is required for long-term battery use. For example, when the addition amount of vinylene carbonate or the like is increased, there is a possibility that deterioration during high-temperature storage can be suppressed even in a highly charged state. However, an increase in the amount of vinylene carbonate or the like may impair the battery output.

  Accordingly, an object of the present invention is to suppress the deterioration of the lithium ion battery without lowering the output and to achieve a long life.

  The present invention provides a method for recovering a degraded lithium ion battery. A method for recovering a lithium ion battery comprising a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte solution, wherein the potential of the negative electrode is increased above that of the positive electrode, and then the potential of the negative electrode is increased. The step of lowering the positive electrode is performed at least one cycle or more.

  Moreover, it is a power supply system which mounts a lithium ion battery, Comprising: It has a means to recover the reduced performance. Specifically, after the lithium ion battery, a power source for applying a potential to the positive electrode and the negative electrode of the lithium ion battery, and controlling the power source, the potential of the negative electrode of the lithium ion battery is made higher than the potential of the positive electrode, A power supply control device that lowers the potential of the negative electrode to be lower than the potential of the positive electrode is provided.

  According to the above configuration, the performance of the deteriorated battery can be recovered and the battery can be used for a long time.

It is a block diagram showing a schematic structure of a power supply system of a first embodiment. It is a block diagram which shows schematic structure of the power supply system of 2nd embodiment. It is sectional drawing of the lithium ion battery which has an additive holding | maintenance part.

  From the viewpoints of environmental protection and energy saving, hybrid vehicles using an engine and a motor as a power source have been developed and commercialized. In the future, fuel cell hybrid vehicles that use fuel cells instead of engines are also being actively developed. A secondary battery capable of repeatedly charging and discharging electricity as an energy source of this hybrid vehicle is an essential technology. Among them, the lithium ion battery is a battery having a high operating voltage and a high energy density that easily obtains a high output, and is becoming increasingly important as a power source for a hybrid vehicle in the future.

  The performance of lithium ion batteries deteriorates due to use, long-term storage, etc., and the deterioration is likely to proceed especially when stored at a high temperature of 50 ° C. or higher and high charge. Although many studies have been made on deterioration suppression techniques, output characteristics may be affected. According to the method for suppressing deterioration and restoring the performance of the deteriorated lithium ion battery and the power supply system including the means for recovering the battery performance, the lowered battery performance can be recovered and the battery can be used for a long time.

  Therefore, the present invention is a power supply system including a method for recovering battery performance and a means for recovering battery performance, and after increasing the potential of the negative electrode higher than that of the positive electrode, the potential of the lithium ion battery deteriorated by decreasing the potential. Performance can be restored. Further, according to the power supply system of the present invention, when the performance of the lithium ion battery is deteriorated, it can be recovered as appropriate, so that it can be used for a long period of time.

  Hereinafter, a power supply system will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a schematic configuration example of the power supply system according to the first embodiment. The power supply system includes a lithium ion battery 50 and a power supply device 100 connected to the lithium ion battery 50. The power supply device 100 includes an external power supply 20, a power supply control device 30, and a state detection unit 40. The lithium ion battery 50 includes at least a positive electrode capable of inserting and extracting lithium ions, a negative electrode capable of inserting and extracting lithium ions, a separator disposed between the positive electrode and the negative electrode, and an electrolytic solution. In the power supply device 100, after increasing the potential of the negative electrode of the lithium ion battery 50, the step of decreasing the potential is performed for at least one cycle. The regeneration mechanism is that the components in the SEI (solid electrolyte interface) coating on the negative electrode surface are gasified and reduced in molecular weight by electrolysis by the regeneration operation, so that the coating is removed and the negative electrode surface is regenerated. It is in. In the power supply system, the power supply device 100 and the lithium ion battery 50 may be integrated, or the power supply device 100 may be configured as a separate battery regeneration device.

  The external power source 20 increases the potential of the negative electrode of the lithium ion battery 50 by applying a voltage to the lithium ion battery 50 as a potential adjusting means. The external power supply 20 includes a variable power supply including a DC power supply and a variable resistor, or a pulse power supply that applies a pulse voltage, and is controlled by the power supply control device 30. The state detection unit 40 detects the voltage and temperature of the lithium ion battery 50. The power supply control device 30 serves as a control means to process a signal detected by the state detection unit 40 and control the external power supply 20. The power supply control device 30 is, for example, a general general-purpose computer, and includes a CPU 31 and a memory 32. The CPU 31 functions as a control unit that controls the external power supply 20. The memory 32 stores a signal sent from the state detection unit 40.

  As a control method by the power supply control device, after increasing the potential of the negative electrode in the lithium ion battery, the means for decreasing the potential is implemented for at least one cycle. The potential of the negative electrode is preferably higher than that of the positive electrode in the range of 0.1 V to 2 V. Further, when the potential is lowered thereafter, the potential of the negative electrode is preferably lowered in the range of 0.1 V or more and 5 V or less than the potential of the positive electrode. The negative electrode potential is monitored by the state detection unit 40, and is controlled by the external power source 20 so as to be at least 0.1 V or more and 2 V or more at the maximum with respect to the positive electrode potential. The potential rise time is at least 0.1 second and at most 30 seconds. Further, after the potential rise, the reverse potential control is performed in a pulsed manner from the external power source 20 so as to be at least 0.1 V or less and 5 V or less at the maximum with respect to the positive electrode potential. By this pulse reverse potential control, dissolved copper ions can be deposited on the copper foil, which is preferable from the viewpoint of short circuit suppression. Moreover, it is preferable from the viewpoint that the resistance increase by the nitride film can be suppressed as compared with the dissolution preventing technique by the nitride film on the copper foil.

  The timing for performing the regenerating operation for increasing the negative electrode potential is not particularly limited. For example, a circuit that allows the power supply control device to automatically increase the negative potential is incorporated, and a regeneration operation is automatically performed after a certain period of time has elapsed since the start of battery use or when the battery resistance value exceeds a predetermined value. You can go. Manual operation is also acceptable. Further, a used battery such as a mobile phone or a hybrid vehicle may be collected, and the negative electrode potential may be increased to perform a regeneration operation.

  The number of playback operations is not particularly limited. The number of operations is at least 1 cycle, but less than 10 cycles, preferably 1 cycle. A large number of cycles is not preferable because the number of dissolution and precipitation of copper increases and there is a possibility of short-circuiting due to dendrite precipitation.

  The reproduction operation frequency is not particularly limited. For example, the reproduction operation may be performed every time the battery resistance increases by about 20% with the information of the state detection unit below. When the battery resistance increases by 20% or more compared to the initial value, the ratio of non-reproducible SEI film components such as lithium fluoride may be high and it becomes difficult to regenerate. It is preferable to implement. On the other hand, if the regeneration frequency is too high, the number of times of dissolution and precipitation of copper increases, which may cause a short circuit due to dendrite precipitation.

  The regeneration action of the SEI film on the negative electrode surface is that the components in the SEI film on the negative electrode surface are gasified or reduced in molecular weight by electrolysis by the regeneration operation, so that the film is removed and the negative electrode surface is regenerated. is there. After the deteriorated film is removed, it is preferable to recharge the SEI by adding an electrolyte additive for forming a new SEI.

  FIG. 2 is a block diagram illustrating an example of a power supply system according to the second embodiment. The power supply system described in this example has a function of adding an additive to the electrolytic solution stored in the lithium ion battery 50. The power supply system of this example includes an external power supply 20, a power supply control device 30, a state detection unit 40 and an actuator 60, and a lithium ion battery 70. The lithium ion battery 70 has an electrolytic solution additive holding unit 16.

  The external power supply 20 increases the potential of the negative electrode of the lithium ion battery 70 by applying a voltage to the lithium ion battery 70 as a potential adjusting means. After the potential of the negative electrode in the lithium ion battery 70 is increased from that of the positive electrode, a means for decreasing the potential is implemented for at least one cycle, and then an electrolyte additive is added to the lithium ion secondary battery. The actuator 60 connected to the power supply control device 30 has a function of releasing the additive into the lithium ion battery 70 by applying stress to the electrolyte solution holding part 16 in the lithium ion battery 70. A predetermined amount of electrolyte additive is stored in the electrolyte additive holder 16 in a state of being isolated from the electrolyte. In order to release the electrolytic solution additive into the electrolytic solution, the electrolytic solution additive-containing capsule is broken with a T-shaped jig or the like inherent in the storage portion, and the additive is pushed out into the electrolytic solution. Since highly durable SEI formation with an additive is performed again after removal of the negative electrode film, deterioration after regeneration can be suppressed as compared with the case where no additive is released.

  FIG. 3 is a cross-sectional view illustrating an example of a cylindrical lithium ion battery including an electrolytic solution additive holding unit. The positive electrode mixture layer 2 formed on the positive electrode current collector 1 is opposed to the negative electrode mixture layer 4 formed on the negative electrode current collector 3 through a separator 7 containing an electrolytic solution. An electrode group consisting of positive and negative electrodes wound or laminated is inserted into the negative electrode battery can 13, one end of the nickel negative electrode lead 9 is welded to the negative electrode current collector 3, and the other end of the negative electrode lead 9 is the negative electrode It is welded to the battery can 13. Further, in order to collect the positive electrode, one end of the positive electrode lead 10 made of aluminum is welded to the positive electrode current collector 1, the other end of the positive electrode current collector 1 is welded to the current cutoff valve 8, and this current It is electrically connected to the positive battery lid 15 via the shutoff valve 8. In the figure, 11 is a positive insulator, 12 is a negative insulator, 14 is a gasket, and 15 is a positive battery cover.

  In FIG. 3, the electrolytic solution additive holding unit 16 is provided on the lid of the battery. The method of storing the electrolyte additive is preferably held in a capsule made of plastic such as polyethylene, polypropylene, or fluorine resin that is hardly soluble in the electrolyte, and the capsule is placed in the lid on the top of the can of the lithium ion battery. Or in the cap of the injection port.

  As an electrolytic solution additive, vinylene carbonate (VC), methyl vinylene carbonate (MVC), dimethyl vinylene carbonate (DMVC), ethyl vinylene carbonate (EVC), diethyl vinylene carbonate (DEVC), dimethallyl carbonate (DMAC), or the like is used. be able to. In particular, VC is preferable because it has a low molecular weight and is considered to form a dense electrode film. MVC, DMVC, EVC, DEVC, and the like in which an alkyl group is substituted for VC are considered to form an electrode film having a low density in accordance with the size of the alkyl chain, and are considered to act effectively to improve low-temperature characteristics.

A positive electrode of a lithium ion battery is formed by applying a positive electrode mixture layer composed of a positive electrode active material, an electronic conductive material, and a binder onto an aluminum foil as a current collector. Moreover, you may add a electrically conductive agent to the positive mix layer for reduction of electronic resistance. The positive electrode active material has a composition formula Li _α Mn _x M 1 _y M 2 _z O ₂ (wherein M 1 is at least one selected from Co and Ni, and M 2 is Co, Ni, Al, B, Fe, Mg, Cr) X + y + z = 1, 0 <α <1.2, 0.2 ≦ x ≦ 0.6, 0.2 ≦ y ≦ 0.4, 0.05 ≦ z ≦ 0.4. ) Is preferable. Among these, it is more preferable that M1 is Ni or Co and M2 is Co or Ni. LiMn _1/3 Ni _1/3 Co _1/3 O ₂ is more preferable. In the composition, if Ni is increased, the capacity can be increased, if Co is increased, the output at a low temperature can be improved, and if Mn is increased, the material cost can be suppressed. In addition, the additive element is effective in stabilizing the cycle characteristics. In addition, the general formula LiM _x PO ₄ (M: Fe or Mn, 0.01 ≦ X ≦ 0.4) and LiMn _1-x M _x PO ₄ (M: divalent cation other than Mn, 0.01 ≦ An orthorhombic phosphate compound having symmetry of the space group Pmnb where X ≦ 0.4) may be used. In particular, LiMn _1/3 Ni _1/3 Co _1/3 O ₂ has high low-temperature characteristics and high cycle stability, and is suitable as a lithium battery material for hybrid vehicles (HEV).

  The binder may be any material as long as the material constituting the positive electrode and the current collector for the positive electrode are in close contact with each other. For example, a homopolymer or copolymer such as vinylidene fluoride, tetrafluoroethylene, acrylonitrile, ethylene oxide, styrene-butadiene, or the like. Examples include rubber. The conductive agent is, for example, a carbon material such as carbon black, graphite, carbon fiber, and metal carbide, and each may be used alone or in combination.

The negative electrode is formed by applying a negative electrode mixture layer composed of a negative electrode active material and a binder onto a copper foil as a current collector. Further, a conductive agent may be further added to the negative electrode mixture layer in order to reduce electronic resistance. The negative electrode active material includes, as a negative electrode active material, natural graphite, a composite carbonaceous material in which a film formed on a natural graphite by a dry CVD (Chemical Vapor Deposition) method or a wet spray method, epoxy, Carbon materials such as artificial graphite and amorphous carbon materials made by firing from resin materials such as phenol or pitch materials obtained from petroleum and coal, or occlusion of lithium by forming compounds with lithium An oxide or nitride of a Group 4 element such as silicon, germanium, or tin, which can form and release lithium metal, form a compound with lithium, and intercalate and release lithium by being inserted into the crystal gap, can be used. In some cases, these are generally referred to as negative electrode active materials. In particular, the carbonaceous material is a material having high conductivity, and excellent in terms of low temperature characteristics and cycle stability. Among the carbonaceous materials, a material having a wide carbon network surface layer (d ₀₀₂ ) is excellent in rapid charge / discharge and low temperature characteristics, and is suitable. However, since a material with a wide d ₀₀₂ may have a reduced capacity and a low charge / discharge efficiency at the initial stage of charging, d ₀₀₂ is preferably 0.390 nm or less. May be called. Furthermore, a carbonaceous material having high conductivity such as graphite, amorphous, activated carbon or the like may be mixed to constitute the electrode. Alternatively, a material having the characteristics shown in (1) to (3) below may be used as the graphite material.

(1) peak in the range of 1300～1400Cm ^-1 measured by Raman spectrum intensity (I _D) and the peak intensity in the range of 1580～1620Cm ^-1 as measured by Raman spectroscopy spectra (I _G) and the The R value (I _D / I _G ), which is an intensity ratio, is 0.20 or more and 0.40 or less. (2) The peak half-value width Δ value in the range of 1300 to 1400 cm ⁻¹ measured by a Raman spectrum is 40 cm ^-1 or more 100 cm ^-1 or less (3) the intensity ratio X values of the peak intensity of the (110) plane in X-ray diffraction (I ₍₁₁₀₎₎ and (004) plane peak intensity (I ₍₀₀₄₎₎ (I ₍₁₁₀₎ / I ₍₀₀₄₎ ) is 0.10 or more and 0.45 or less

  As the binder, any material may be used as long as the material constituting the negative electrode and the current collector for the negative electrode are brought into close contact with each other. For example, a homopolymer or copolymer such as vinylidene fluoride, tetrafluoroethylene, acrylonitrile, ethylene oxide, styrene- Examples thereof include butadiene rubber. The conductive agent is, for example, a carbon material such as carbon black, graphite, carbon fiber, and metal carbide, and each may be used alone or in combination.

  As the electrolytic solution, a highly polar (high polarity) solvent, a low polarity (low polarity) solvent, a mixed solvent of the electrolytic solution additive, and a lithium salt are used. High polar solvents are propylene carbonate (PC), ethylene carbonate (EC), trifluoropropylene carbonate (TFPC), chloroethylene carbonate (ClEC), fluoroethylene carbonate (FEC), trifluoroethylene carbonate (TFEC), difluoroethylene. Carbonate (DFEC), vinyl ethylene carbonate (VEC), etc. can be used. In particular, it is preferable to use EC from the viewpoint of film formation on the negative electrode. In addition, addition of a small amount (2 vol% or less) of ClEC, FEC, TFEC, or VEC is also involved in electrode film formation and provides good cycle characteristics. Furthermore, TFPC and DFEC may be used by adding a small amount (2 vol% or less) from the viewpoint of film formation on the positive electrode. Low polar solvents are dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), trifluoromethyl ethyl carbonate (TFMEC), 1,1 1, 1-trifluoroethyl methyl carbonate (TFEMC) or the like can be used. DMC is a highly compatible solvent and is suitable for use in a mixture with EC or the like. DEC has a lower melting point than DMC and is suitable for low temperature (−30 ° C.) characteristics. EMC is suitable for low temperature characteristics because of its asymmetric molecular structure and low melting point. Since EPC and TFMEC have propylene side chains and an asymmetric molecular structure, they are suitable as adjusting solvents for low temperature characteristics. TFEMC fluorinates part of the molecule and has a large dipole moment, which is suitable for maintaining the dissociation property of the lithium salt at a low temperature, and is suitable for low temperature characteristics. As for the mixing ratio of the electrolyte solution, the composition ratio of the high polarity solvent is 18.0 to 30.0 vol%, the composition ratio of the low polarity solvent is 74.0 to 81.8 vol%, and the composition ratio of the electrolyte solution additive Is 0.1 to 1.0 vol%. Here, when the composition ratio of the electrolytic solution additive is 1.0 vol% or more, the internal resistance of the battery is increased, and the output of the battery is decreased.

The lithium salt used for the electrolytic solution is not particularly limited, but for inorganic lithium salts, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiI, LiCl, LiBr, etc., and for organic lithium salts, 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 or the like can be used. In particular, LiPF ₆ frequently used in consumer batteries is a suitable material because of the stability of quality. LiB [OCOCF ₃ ] ₄ is an effective material because it has good dissociation and solubility and exhibits high conductivity at a low concentration.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to specific examples.

  The direct current resistance of a deteriorated lithium ion battery having a battery capacity of 800 mAh was measured. The direct current resistance was measured using the following method. The battery was charged at a constant current of 0.7 A to 4.1 V, charged at a constant voltage of 4.1 V until the current value reached 20 mA, and after 30 minutes of operation stop, discharged at 0.7 A to 2.7 V. This operation was repeated three times. The battery is then charged to 3.8V at a constant current of 0.7A, discharged at 10A for 10s, charged again to 3.8V at a constant current, discharged at 20A for 10s, charged to 3.8V again, and 30A Was discharged for 10 s. The direct current resistance of the battery was evaluated from the IV characteristics at this time. The evaluation result was 65Ω. The temperature during measurement is 25 ° C.

  Using the above-described deteriorated lithium ion battery, it was connected to an external power supply and a power supply control device to produce a power supply system. The power supply control device 30 applied a voltage 1 V higher than the positive terminal to the negative electrode terminal in the lithium ion battery for 10 seconds. Further, after a pause of 1 second, control was performed to apply a voltage 2 V lower than the positive terminal for 10 seconds.

  After the above regeneration operation, DC resistance evaluation was performed. As a result, it was confirmed that the resistance was reduced by 20%. Therefore, as described above, the negative electrode voltage is applied to raise the negative electrode potential above the positive electrode, and then the negative electrode potential is lowered below the positive electrode to reduce the resistance increased due to deterioration, and the battery is regenerated. Confirmed to do.

  Further, the lithium ion battery was charged to a battery voltage of 4.1 V, and then allowed to stand at 50 ° C. for 1 month to evaluate DC resistance. As a result, the resistance increased by 5%.

  In this example, a battery system was manufactured using a lithium ion battery having an additive holding portion in the battery. The direct current resistance of the deteriorated lithium ion battery at a battery capacity of 800 mAh was measured by the same method as in Example 1. The evaluation result was 64Ω.

  Using a lithium-ion battery that had been measured for DC resistance, an external power supply, power supply controller, and actuator were connected to create a power supply system. Similarly to Example 1, a voltage 1V higher than the positive electrode terminal was applied to the negative electrode terminal in the lithium ion battery for 10 seconds by the power supply control device. Further, after a pause of 1 second, a voltage 2 V lower than the positive terminal was applied for 10 seconds. Thereafter, stress was applied to the electrolytic solution additive holding unit 16 by the actuator 60 to release a dimethyl carbonate solution containing 0 wt% vinylene carbonate as an additive into the battery.

  After the above regeneration operation, DC resistance evaluation was performed. As a result, 20% resistance reduction was confirmed.

  Further, the lithium ion battery was charged to a battery voltage of 4.1 V, and then allowed to stand at 50 ° C. for 1 month to evaluate DC resistance. As a result, the resistance increased by 4%.

  In this example, a battery system was manufactured using a lithium ion battery having an additive holding portion in the battery. The direct current resistance of the deteriorated lithium ion battery at a battery capacity of 800 mAh was measured by the same method as in Example 1. The evaluation result was 64Ω.

  Using a lithium-ion battery that had been measured for DC resistance, an external power supply, power supply controller, and actuator were connected to create a power supply system. Similarly to Example 1, a voltage 1V higher than the positive electrode terminal was applied to the negative electrode terminal in the lithium ion battery for 10 seconds by the power supply control device. Further, after a pause of 1 second, a voltage 2 V lower than the positive terminal was applied for 10 seconds. Thereafter, stress was applied to the electrolytic solution additive holding unit 16 by the actuator 60 to release a dimethyl carbonate solution containing 10 wt% vinylene carbonate as an additive into the battery.

  After the above regeneration operation, DC resistance evaluation was performed. As a result, 20% resistance reduction was confirmed.

  Further, the lithium ion battery was charged to a battery voltage of 4.1 V, and then allowed to stand at 50 ° C. for 1 month to evaluate DC resistance. As a result, the resistance increased by 1%. Therefore, by adding an additive to the electrolytic solution, it was possible to suppress performance deterioration after being left at 50 ° C. as compared with Example 2. It is considered that during the 4.1 V charge after the addition, SEI formation which is difficult to deteriorate occurs due to electrochemical reductive decomposition of the additive, and the deterioration after regeneration is suppressed.

[Comparative Example 1]
Similar to Examples 1 and 2, the DC resistance of a deteriorated lithium ion battery having a battery capacity of 800 mAh was measured, and then a voltage 1 V higher than the positive electrode terminal was applied to the negative electrode terminal in the lithium ion battery for 10 seconds. After this operation, DC resistance evaluation was performed. As a result, an internal short circuit occurred, the battery function was impaired, and the performance of the deteriorated battery was not recovered. As a result of battery disassembly, it was clarified that the reason for the short circuit originated from copper deposited on the negative electrode surface.

  As is clear from the above examination, the resistance is reduced and the battery is regenerated by performing at least one cycle of the step of lowering the potential of the lithium ion battery after the potential of the negative electrode is raised from that of the positive electrode. The effect was confirmed. Furthermore, the effect which suppresses the further deterioration after reproduction | regeneration was acquired by adding electrolyte solution additive in electrolyte solution with said process. Since highly durable SEI formation with an additive is performed again after the removal of the negative electrode film, deterioration after regeneration can be suppressed as compared with the case where no additive is released.

  In addition, when the step of simply increasing the potential and decreasing the potential was not performed, recovery of the battery performance could not be confirmed.

DESCRIPTION OF SYMBOLS 1 Positive electrode collector 2 Positive electrode mixture layer 3 Negative electrode collector 4 Negative electrode mixture layer 7 Separator 8 Current cutoff valve 9 Negative electrode lead 10 Positive electrode lead 11 Positive electrode insulator 12 Negative electrode insulator 13 Negative electrode battery can 14 Gasket 15 Positive electrode battery lid 16 Electrolysis Liquid additive holding unit 20 External power supply 30 Power supply control device 31 CPU
32 Memory 40 State detection unit 50, 70 Lithium ion battery 60 Actuator 100, 200 Power supply

Claims (10)

  A lithium-ion battery, an external power supply that applies a potential to the lithium-ion secondary battery and has a negative electrode potential higher than a positive electrode potential, and a power supply control device that controls the external power supply And power system. The power supply system according to claim 1,
A power supply system comprising a state detection unit for detecting a state of the lithium ion battery. The power supply system according to claim 1 or 2,
A power supply system comprising: an additive holding unit that holds an additive added to the electrolytic solution of the lithium ion battery; and an actuator that releases the additive held in the additive holding unit into the electrolytic solution. . A power supply system according to claim 3, wherein
The power supply system according to claim 1, wherein the additive includes at least one of vinylene carbonate, methyl vinylene carbonate, dimethyl vinylene carbonate, ethyl vinylene carbonate, diethyl vinylene carbonate, and dimethallyl carbonate. A power supply system according to claim 3, wherein
The power supply system, wherein the additive holding part is provided inside the lithium ion battery. The power supply system according to claim 1,
The power supply control device sets the negative electrode potential to a high level in a range of 0.1 V to 2 V with respect to the positive electrode potential, and then sets the negative electrode potential to 0.1 V to 5 V with respect to the positive electrode potential. A power supply system characterized by a low state in the range. The power supply system according to claim 1,
The power supply control device sets the negative electrode potential to be higher than the positive electrode potential for 0.1 to 30 seconds. A battery regeneration method for improving the performance of a lithium ion battery,
A regeneration method comprising performing at least one cycle of a potential control step of setting the potential of the negative electrode lower than that of the positive electrode after setting the negative electrode of the lithium ion battery to a potential higher than that of the positive electrode. A method for regenerating a lithium ion battery according to claim 8,
A regeneration method comprising a step of adding an electrolyte solution additive in the lithium ion secondary battery after the potential control step. A method for regenerating a lithium ion battery according to claim 8,
A regeneration method comprising performing the potential control step after a predetermined period of time has elapsed from the start of battery use or when a predetermined battery resistance value is reached.

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