WO2015136683A1

WO2015136683A1 - Lithium ion secondary battery

Info

Publication number: WO2015136683A1
Application number: PCT/JP2014/056818
Authority: WO
Inventors: 宏文 ▲高▼橋; 安藤　慎輔
Original assignee: 株式会社日立製作所
Priority date: 2014-03-14
Filing date: 2014-03-14
Publication date: 2015-09-17

Abstract

The present invention provides a lithium ion secondary battery that allows the lifespan of the battery to be extended by adding an electrolytic solution additive through a mechanism that includes no moving parts, the additive being capable of canceling a decrease in capacity during storage under a relatively high temperature environment or caused by a secondary reaction that proceeds with the use of the battery through multiple charge-discharge cycles, or capable of suppressing a further progress of the secondary reaction, without causing the positive electrode to reach excessive discharge prior to initial charging. The lithium ion secondary battery is characterized in that: an electrode group comprising lithium ion secondary battery electrodes and separators disposed alternately, a battery can whereby the electrode group is housed, and a lifespan-extending material disposed inside the battery can are provided; and the electrodes are connected to the lifespan-extending material through a switch.

Description

Lithium ion secondary battery

The present invention relates to a non-aqueous secondary battery, for example, a high energy density lithium ion secondary battery suitable for use in portable equipment, electric vehicles, power storage and the like.

It is known that a lithium ion secondary battery using a carbon material as a negative electrode active material can form a film on the surface of the negative electrode due to a side reaction associated with the negative electrode charging reaction at the first charge after the battery is manufactured. In addition, it is known that an alloy negative electrode active material containing silicon and tin, which has been actively studied as a high capacity negative electrode active material in recent years, has a larger amount of side reactions than the carbon material.

Due to these side reactions, once charged lithium ions are fixed in the negative electrode and cannot be discharged at all, that is, an irreversible capacity is generated that some of the lithium ions charged in the negative electrode cannot be discharged, It is known to cause a reduction in the capacity of the entire battery.

As a prior art for solving this problem, Patent Document 1 discloses that at least one of the positive electrode, the negative electrode, and the separator is formed with an alkali metal powder layer present on the surface, and the alkali metal powder layer is “It is formed by a step of coating an alkali metal composition on a current collector on which a polymer film or an active material layer is formed and a step of drying the coated polymer film or current collector”. A lithium secondary battery is disclosed.

The technique disclosed in Patent Document 1 aims to “provide a lithium secondary battery exhibiting an excellent energy density by reducing the initial irreversible capacity during charging and discharging of the battery”. Further, Patent Document 2 discloses a technique of “making a lithium powder exist on the separator surface” and aims to “obtain a non-aqueous electrolyte secondary battery with high initial efficiency and high cycle retention”.

Further, regarding lithium powder, “a material having an environmentally stable surface, for example, organic rubber such as NBR (nitrile butadiene rubber) and SBR (styrene butadiene rubber), organic resin such as EVA (ethylene vinyl alcohol copolymer resin), and Li ₂ A technique using a “stabilized lithium powder” coated with an inorganic compound such as a metal carbonate such as CO ₃ is disclosed. Furthermore, the amount of lithium added is determined after the initial efficiency of the negative electrode is obtained, so that “deterioration of lithium powder does not proceed even in a dry room with a dew point of −40 ° C.” and the amount of lithium added is too large. Therefore, an object of the present invention is to provide a non-aqueous electrolyte secondary battery that does not “deposit lithium on the negative electrode and conversely reduce the capacity of the battery”.

In addition, various electrolyte additives are used to suppress the overall performance degradation of the battery due to the side reaction. However, it is known that when a large amount of electrolyte additive is added during battery manufacture, the internal resistance increases, and necessary and sufficient electrolyte additive is added during battery manufacture even after the battery has deteriorated due to long-term use. It is difficult to keep.

As a prior art to solve this problem, Patent Document 3 additionally supplies an additive into a battery by “breaking the electrolyte additive-containing capsule with a T-shaped jig or the like and pushing the additive into the electrolyte”. Techniques to do this are disclosed.

The technology disclosed in Patent Document 3 is “addition of an electrolytic solution additive for forming a new SEI after the deteriorated film is removed, and reforming the SEI”. The purpose is to “suppress performance degradation due to growth of the coating film, etc., in particular, reduction in output due to resistance rise”.

JP 2005-317551 A JP 2008-048442 A JP 2012-169094 A

The approach of lithium supply as in the prior art is aimed at eliminating the initial irreversible capacity of the positive electrode and / or negative electrode active material.

However, it is known that the side reaction proceeds not only in the initial stage but also in the subsequent storage state and use state, for example, during storage in a relatively high temperature environment, or with a large number of charge / discharge cycles. As a result, a new phenomenon occurs in which lithium ions are fixed in the negative electrode. As a result, there is a problem that the capacity of the battery is reduced due to the potential of the positive electrode or the negative electrode being shifted to the high potential side and the charge / discharge range being reduced.

In addition, when lithium is supplied directly to the positive electrode using the conventional technology, the positive electrode and the metal lithium react before the first charge, and the positive electrode falls into an overdischarged state and there is a concern that the battery characteristics may deteriorate. .

Furthermore, the efforts to supply the electrolyte additive as in the prior art require a space for the movable part to use the actuator mechanism having the movable part, which increases the volume of the battery, thereby increasing the energy of the battery. There exists a subject that a density will fall.

The present invention has been made in view of the above problems, and the object of the present invention is to prevent the positive electrode from being overdischarged before the initial charge, and at the time of storage in a relatively high temperature environment, To eliminate capacity reduction due to side reactions that have progressed with the use of the battery, such as charge / discharge cycles, and to add an electrolyte additive that can suppress further side reactions by a mechanism that does not include moving parts An object of the present invention is to provide a lithium ion secondary battery capable of extending the battery life.

In order to solve the above problems, a lithium ion secondary battery of the present invention includes an electrode group in which electrodes and separators are alternately arranged, a battery can in which the electrode group is stored, and a life extension that is arranged in the battery can. The electrode is connected to the life extension material through a switch.

According to the present invention, it is possible to supply lithium ions to the positive electrode and / or the negative electrode, and it is possible to improve the capacity drop due to the lithium ions being fixed in the negative electrode by a side reaction. Moreover, it becomes possible to supply an electrolyte solution additive at an appropriate timing, and it is possible to ensure a necessary amount of the electrolyte solution additive even at the time of battery deterioration without excessive addition at the initial stage.

FIG. 3 is an exploded perspective view showing the lithium ion secondary battery in Example 1 in a partial cross section. Sectional drawing which shows typically the structure of the positive electrode in Example 1, and an ion supply part. Charge / discharge characteristics of positive electrode and negative electrode before occurrence of capacity reduction of lithium ion secondary battery in Example 1 Charge / discharge characteristics of the positive electrode and the negative electrode before and after the decrease in capacity of the lithium ion secondary battery in Example 1 Sectional drawing which shows typically the structure which has arrange | positioned resistance between the positive electrode in Example 1, and an ion supply part. Sectional drawing which shows typically the structure of the negative electrode in Example 2, and an ion supply part. Sectional drawing which shows typically the structure of the positive electrode in Example 3, and an electrolyte solution additive supply part. Sectional drawing which shows typically the structure which provided the positive electrode in Example 3, and the some electrolyte solution supply part. Sectional drawing which shows typically the structure of the negative electrode in Example 4, and several electrolyte solution supply part. The system configuration in this embodiment. The flowchart which shows the charging / discharging control method of this embodiment. Sectional drawing of the lithium ion secondary battery of this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following examples, a case of a lithium ion secondary battery will be described as an application example of the nonaqueous secondary battery of the present invention.

Example 1
FIG. 1 is an exploded perspective view showing a configuration of the lithium ion secondary battery in the present embodiment in a partial cross section.

The lithium ion secondary battery C1 is a cylindrical wound type that is mounted on, for example, a hybrid vehicle or an electric vehicle, and as shown in FIG. The wound electrode group 8 is housed.

The electrode group 8 includes a belt-like positive electrode 11 and a negative electrode 21 which are layered with a porous and insulating separator 10 interposed therebetween and wound around a resin-made shaft core 7. It is configured by fixing the separator 10 with a tape.

The positive electrode 11 has a positive electrode foil 12 made of an aluminum foil and a positive electrode mixture layer 13 coated on both surfaces of the positive electrode foil 12. A plurality of positive electrode tabs 12a are provided on the upper long side of the positive electrode foil 12 in the figure.

The negative electrode 21 has a negative electrode foil 22 made of copper foil and a negative electrode mixture layer 23 coated on both surfaces of the copper foil 22. A plurality of negative electrode tabs 22a are provided on the long side of the negative electrode foil 22 in the lower part of the figure.

The positive electrode current collector plate 5 and the negative electrode current collector plate 6 are fixed to both ends of the tubular shaft core 7 by fitting. A positive electrode tab 12a is welded to the positive electrode current collector plate 5 by, for example, an ultrasonic welding method. Similarly, the negative electrode tab 22a is welded to the negative electrode current collector plate 6 by, for example, an ultrasonic welding method.

Inside the battery can 1 that also serves as a terminal for the negative electrode 21, a positive electrode current collector plate 5 and a negative electrode current collector plate 6 are attached and housed in an electrode group 8 wound around a resin shaft 7. Yes. At this time, the electrolytic solution is also injected into the battery can 1. A gasket 2 is provided between the battery can 1 and the upper lid case 3b. The gasket 2 seals the opening of the battery can 1 and electrically insulates it.

On the positive electrode current collector plate 5, there is an electrically conductive upper lid portion 3 provided so as to seal the opening of the battery can 1. The upper lid 3 includes an upper lid 3a and an upper lid case 3b. One of the positive electrode leads 9 is welded to the upper lid case 3 b and the other is welded to the positive electrode current collector plate 5, whereby the upper lid portion 3 and the positive electrode of the electrode group 8 are electrically connected.

The positive electrode mixture layer 13 includes a positive electrode mixture containing a positive electrode active material, a conductive agent, and a binder. The negative electrode mixture layer 23 includes a negative electrode active material, a negative electrode binder resin, and a thickener. A negative electrode mixture containing The positive electrode mixture layer 13 and the negative electrode mixture layer 23 are prepared by preparing a dispersed solution of substances constituting the mixture, applying the mixture slurry onto a metal foil, drying, and pressing after drying. Formed by.

Examples of the coating method include a slit die coating method and a roll coating method. Further, N-methylpyrrolidone (NMP), water or the like can be used as a solvent for the dispersion solution. Furthermore, examples of the drying method include hot air circulation, infrared heating, and a mixing method thereof. As a pressing method, it is possible to press and compress from both sides of the electrode with a cylindrical metal roller from both sides of the electrode.

In this embodiment, the positive electrode 11 uses LiCoO ₂ as the positive electrode active material. Then, 7% by weight of acetylene black as a conductive agent and 5% by weight of polyvinylidene fluoride (PVDF) as a binder are added to the positive electrode active material, and N-methyl-2-pyrrolidone is added thereto and mixed. A slurry was prepared. This positive electrode mixture slurry is applied to both surfaces of the positive electrode foil 12 which is an aluminum foil having a thickness of 25 μm (FIG. 2 shows only one side. For simplification, the mixture layer is shown only on one side in the following drawings). By drying and pressing and cutting, the positive electrode mixture was bound to both surfaces of the positive electrode foil 12 to form the positive electrode mixture layer 13, thereby forming the positive electrode 11.

Similarly, the negative electrode 21 uses non-graphitizable carbon as a negative electrode active material. Then, 8 wt% of PVDF as a binder was added to the negative electrode active material, and N-methyl-2-pyrrolidone was added thereto and mixed to prepare a negative electrode mixture slurry. The negative electrode mixture slurry is applied to both surfaces of a negative electrode foil 22 which is a copper foil having a thickness of 10 μm, dried, pressed and cut, thereby binding the negative electrode mixture to both surfaces of the negative electrode foil 22 and negative electrode mixture. The layer 23 was formed and used as the negative electrode 21.

Hereinafter, features of the present invention will be described in detail. One feature of the present invention is that the life extending member is connected to the electrode through a switch.

FIG. 2 is a cross-sectional view schematically showing the configuration of the positive electrode 11 and the ion supply unit 31 in the present embodiment, using the ion supply unit 31 as the life extension material 203. The positive electrode 11 is provided with an ion supply unit 31. The ion supply unit 31 has a configuration for supplying ions of the same type as ions responsible for charge / discharge when electrically connected to the positive electrode 11.

The specific configuration of the ion supply unit 31 is, for example, a configuration made of metallic lithium or silicon or a compound of tin and lithium.

Further, the ion supply unit 31 is connected to the positive electrode foil 12 of the positive electrode 11 via the switch 40 and the wiring 41. Since the switch 40 and the wiring 41 are at the potential of the positive electrode 11 or the ion supply unit 31, it is necessary to use a material that is stable in these states.

In the present embodiment, aluminum is used as the wiring member on the positive electrode 11 side inside the switch 40 from the positive electrode that is always at the positive electrode potential, and the wiring 41 on the ion supply unit 31 side that is affected by the positive electrode potential only when the switch 40 is operated is oxidation resistant. High-quality stainless steel was used. In addition, even if the wiring is other than the above, it is possible to prevent oxidation or reductive decomposition by cutting off the contact with the electrolytic solution. Therefore, if the wiring is coated, various metals can be used as the wiring. .

FIG. 12 shows a specific arrangement relationship of the ion supply unit 31. The ion supply unit 31 was made of about 1 mm square metal lithium. The ion supply unit 31 is fixed to the exposed portion of the positive foil 12 with an electrolyte solution-resistant tape (not shown) through the switch 40. By disposing the ion supply part 31 in the electrode foil exposed part, it becomes possible to utilize a dead space, and it is possible to reduce the size of the lithium ion secondary battery while providing a mechanism capable of recovering the capacity reduction. If the ion supply part 31 is installed in the site | part which has the electric potential of a positive electrode via the switch 40, there will exist the same effect. For example, by installing in advance on the inside of the battery of the upper lid 3 or on the exposed portion of the positive electrode current collector plate 5, the same size reduction as in the case of installing on the exposed portion of the positive foil 12 and assembly equivalent to the conventional one can be made. The process can be simplified.

In addition, since the ion supply unit 31 is in contact with the positive electrode via the switch 40 that can switch electrical connection, the ion supply unit 31 does not react with the positive electrode 11 if the switch 40 is turned off, and the ion supply unit 31 changes to the positive electrode 11. Lithium ions are never supplied.

Accordingly, in an uncharged state, the switch 40 is turned off to prevent a reaction between metallic lithium and the positive electrode, and unlike the case where metallic lithium is simply added to the positive electrode, the positive electrode 11 is overdischarged before the first charge. It will not reach.

Then, after the initial charge, by turning on the switch 40, the ion supply source 31 is brought into contact with the electrolyte while being electrically connected to the positive electrode 11, and the reaction between the positive electrode 11 and the ion supply source 31 is started. The irreversible capacity due to the initial side reaction of the negative electrode 21 can be eliminated by supplying lithium ions from the ion supply source 31 to the positive electrode 11. In addition, also when using the electrolyte solution supply part 34 mentioned later, it is desirable from a viewpoint of size reduction to provide the said electrolyte solution supply part 34 in the foil exposed part of an electrode.

In the above description, the structure in which the ion supply unit 31 (or electrolytic solution additive supply unit 34) is disposed on the positive electrode foil 12 has been described. Naturally, the ion supply unit 31 (or electrolytic solution additive supply) is provided on the negative electrode foil 22. Even with the structure in which the portion 34) is disposed, it is possible to reduce the size of the lithium ion secondary battery while preventing a decrease in capacity.

FIG. 3 is a graph showing charge / discharge curves of the positive electrode and the negative electrode before the capacity reduction of the lithium ion secondary battery occurs. The upper curve shows the charge / discharge characteristics of the positive electrode, and the lower curve shows the charge / discharge characteristics of the negative electrode. There is no capacity shift between the positive electrode and the negative electrode before the capacity drop occurs. Therefore, the capacity indicated by the width between the two white circles is sufficiently secured.

FIG. 4 is a graph showing the charge / discharge characteristics of the positive electrode and the negative electrode after the capacity reduction occurs according to the storage state and use state. The white circles in FIG. 4 are values before the occurrence of capacity reduction, and the black circles are values after the occurrence of capacity reduction. When a side reaction occurs in this way, a capacity shift occurs between the positive electrode and the negative electrode, and a capacity decrease occurs as shown by the width between the two black circles. When the ion supply unit 31 is not functioned as in this embodiment, the capacity is reduced depending on the storage state and the use state.

On the other hand, after completion of the initial charge, after storage at 60 ° C. for 2 days as storage in a high temperature environment, the switch 40 is turned on to perform electrolysis in a state where the ion supply unit 31 is electrically connected to the positive electrode 11. The ion supply part 31 was operated in contact with the liquid. As a result, the state with the capacity reduction shown in FIG. 4 (black circle state) is not reached, and the state without the capacity reduction shown in FIG. 3 (white circle state) can be obtained. It was possible to eliminate the capacity drop due to side reactions that proceeded by storage.

Therefore, in the present invention, the timing of the reaction between the ion supply unit 31 and the positive electrode 11 is controlled, and not only the initial irreversible capacity is eliminated, but also during storage in a relatively high temperature environment and a large number of times of charge / discharge. Capacity reduction due to side reactions that have progressed with the use of the battery, such as cycling, can also be eliminated.

<< Modification of Example 1 >>
Next, a modification of the first embodiment is shown in FIG. In this modified example, a resistor 42 is provided to easily control the current and prevent oxidation or reductive decomposition of the wiring 41 and the switch 40.

In Example 1, since the positive electrode 11 has a potential of about 3 to 4V and the negative electrode has a potential of about 0 to 1V, the potential difference is in the range of 2 to 4V.

The resistance value of the resistor 42 can be determined from this potential difference and the current value allowed by the wiring 41 and the switch 40. In this modification, the resistor 42 having a resistance value of 1 kΩ is used. Note that the lower the resistance value of the resistor 42, the more current flows, so that the reduction in capacity due to the lithium ion supply can be promptly advanced. On the other hand, since an influence such as heat generation occurs when the current is large, it is preferable to use a resistance value in the range of about 1Ω to 10 kΩ.

Further, since the current can be controlled to a predetermined value by using the resistor 42 having a known resistance value, the product of the time when the switch 40 is turned on and the current value is controlled by controlling the time when the switch 40 is turned on. The required supply amount of lithium ions can be easily controlled. Further, when the switch 40 is turned on and a current flows, a potential difference obtained by the product of the current value and the resistance value is generated at both ends of the resistor 42. Therefore, depending on the installation location of the resistor 42, the switch 40 and the wiring 41 described in the citation 1 The potential can be controlled, and the degree of freedom in material selection can be improved.

Example 2
Next, Example 2 will be described. In the first embodiment, the ion supply unit 31 is connected to the positive electrode 11. However, the present embodiment is different from the first embodiment in that the ion supply unit 31 is installed on the negative electrode 21 via the switch 40.

FIG. 6 is a cross-sectional view schematically showing the configuration of the negative electrode 21 and the ion supply unit 31 in the present embodiment.
In the present embodiment, since the wiring 41 and the switch 40 are all at a negative potential, a known negative current collecting material can be used. Or you may protect by interrupting | blocking with electrolyte solution.

In this embodiment, the capacity drop can be eliminated by switching the switch on and off as in the first embodiment. The merit of providing the switch 40 on the negative electrode side is that the connection between the positive electrode and the ion supply unit 31 is a discharge reaction, and the connection between the negative electrode and the ion supply unit 31 is a charge reaction. By providing it, the battery can be charged, and the amount of available energy increases.

Example 3
Next, Example 3 will be described. In the first embodiment, the ion supply unit 31 is used as the life extension material 203, but in this embodiment, the electrolyte solution additive supply unit 34 is used as the life extension material 203.

FIG. 7 is a cross-sectional view schematically showing the configuration of the positive electrode and the electrolyte additive supply unit 34 in this example. The electrolyte additive supply unit 34 oxidizes and decomposes the additive when the electrolyte additive 35 and the additive are separated from the electrolyte and electrically connected to the positive electrode by turning on the switch. It consists of a barrier layer 36 having a function of supplying the electrolyte solution.

More preferably, there is a protective layer 37 that is stable at the positive electrode potential and serves as a container for storing the additive. FIG. 7 shows an example using the protective layer 37.

In this embodiment, vinylene carbonate was used for the electrolytic solution additive 35, an aluminum container was used for the protective layer 37, and a copper foil was used for the barrier layer 36. When the switch is turned on in the configuration of the present embodiment, the copper of the barrier layer 36 is electrically connected to the positive electrode 11, and the electrolytic solution additive 35 is supplied into the electrolytic solution. Note that any known additive can be used as the electrolytic solution additive 33, and in this embodiment, it is reported that the film is formed by reducing and decomposing on the surface of the negative electrode mixture layer 23 to improve the life performance. The vinylene carbonate which was made was used. The barrier layer 36 may be made of a film-like resin that is oxidatively decomposed at the positive electrode potential.

FIG. 8 shows a configuration including two electrolytic solution additive supply units 34. With such a configuration, each electrolyte additive supply unit 34 can be operated at different timings by the switch 40. Therefore, the electrolyte solution additive 35 can be supplied a plurality of times, and the capacity drop can be recovered a plurality of times.

One of the two electrolyte additive supply units 34 may be the ion supply unit 31. In that case, since it is possible to cope with both deterioration due to a decrease in lithium ions and deterioration due to a decrease in electrolytic solution, it is possible to cope with capacity deterioration more variously.

Example 4
Next, Example 4 will be described. In Example 3, the electrolyte solution additive supply unit 34 was connected to the positive electrode 11, but in this example, the point that the electrolyte solution additive supply unit 34 was connected to the negative electrode 21 was different from Example 3.

FIG. 9 is a cross-sectional view schematically showing the configuration of the negative electrode 21 and the electrolyte additive supply unit 34 in the present embodiment. The electrolytic solution additive supply unit 34 performs reductive decomposition when the electrolytic solution additive 35 is electrically connected to the negative electrode 21 by separating the electrolytic solution additive 35 from the electrolytic solution and turning on the switch. It comprises a barrier layer 36 having a function of supplying the electrolytic solution additive 35 into the electrolytic solution. More preferably, there is a protective layer 37 that is stable at the negative electrode potential and serves as a container for storing the electrolyte solution additive 35.

In this example, vinylene carbonate was used for the electrolytic solution additive 35, a copper container was used for the protective layer 37, and a resin film was used for the barrier layer 36. When the switch is turned on in the configuration of the present embodiment, the barrier layer is decomposed by being electrically connected to the negative electrode 21, and the electrolytic solution additive 33 is supplied into the electrolytic solution.

As a reason for the effect of improving the life performance by vinylene carbonate, it has been reported that the film is formed by reducing and decomposing on the surface of the negative electrode mixture layer 23 to improve the life performance. By providing the electrolytic solution additive supply part 34 in the vicinity of the negative electrode, the electrolytic solution additive 35 can be efficiently supplied to the surface of the negative electrode mixture layer 23, and an effect of improving the life performance can be obtained.

Example 5
Next, Example 5 will be described. In this example, a control system for lithium ion secondary batteries shown in Examples 1 to 4 will be described.

FIG. 10 is a system configuration diagram of a control system for a lithium ion secondary battery, and FIG. 11 is a flowchart showing a control algorithm.

The control system of the lithium ion secondary battery C1 includes a charge / discharge control device 100, a controller 105, and an output unit 106, as shown in FIG. The charge / discharge control apparatus 100 includes a battery information acquisition unit 101, a deterioration state determination unit 102, a switch operation determination unit 103, and a control signal transmission unit 104.

The battery information acquisition unit 101 acquires charge / discharge information of the lithium ion secondary battery C1, and the deterioration state determination unit 102 determines the operation of the ion supply unit 31 based on the capacity reduction state of the lithium ion secondary battery C1. Determine no. The switch operation determining unit 103 determines which life extending material is to be operated. The control signal transmission unit 104 transmits the control information determined by the switch operation determination unit 103 to the controller 105. The controller 105 operates the life extending member by switching the switch. Further, the output unit outputs a history of switch operations and the like to the host system and / or the user.

Next, the operation of the control system having the above configuration will be described.

First, the battery information acquisition unit 101 acquires charge / discharge information of the lithium ion secondary battery C1 (step S111). And the deterioration state determination part 102 determines the state of capacity | capacitance reduction of the lithium ion secondary battery C1 (step S112), and it is determined whether supply of lithium ion is required (step S113).

When the switch operation determining unit 103 determines that lithium ion supply or electrolyte additive supply is required (YES in step S113), the lithium ion secondary battery C1 is passed through the control signal transmitting unit 104 and the controller 105. The switch 40 is switched inside to turn on the connection with the ion supply unit 31 or the electrolyte solution supply unit 34 (step S114). Thereafter, the output unit 106 transmits information to the host system or the user (step S115). Here, the information transmitted to the host system is, for example, connection time or ion supply amount of the ion supply unit 31 and history information indicating which electrolyte solution supply unit 34 is used.

On the other hand, if it is determined that supply of lithium ions or supply of electrolyte solution is unnecessary, information is transmitted from the output unit 106 to the host system or user (step S116), and after waiting for a predetermined time (step S117). ) Repeat the diagnosis again.

The control method shown in this embodiment makes it possible to control the operations of the ion supply unit 31 and the electrolyte supply unit more precisely. A known battery performance evaluation method and deterioration estimation method can be used to determine whether or not the ion supply unit 31 and the electrolyte solution supply unit need to be operated. For example, a method for measuring the battery capacity by means of measuring the rated capacity and comparing it with that before deterioration, and a battery internal state estimation method using a discharge curve are known. When the battery capacity falls below a preset value, or when the charge / discharge range of the positive and negative electrodes is estimated from the analysis of the charge and / or discharge curve, and the upper limit of the positive working potential exceeds the preset value. good.

The operational effects of the present invention will be described together. In the present invention, as a life extension material, in the first case where metallic lithium or an alloy-based negative electrode is used as an ion supply source, an electrolytic solution additive composed of an organic solvent such as vinylene carbonate is supplied into the electrolytic solution when the switch is operated. There are a second case in which a mechanism is provided and used in a container, and a third case in which the above two cases are compatible.

In the first case, since the ion supply unit 31 is electrically insulated by the switch 40, it does not reach an overdischarged state due to a reaction between metallic lithium and the positive electrode in an uncharged state. Moreover, since the supply amount of lithium ions can be controlled by controlling the time for which the switch 40 is in the connected state, an arbitrary amount can be obtained without supplying an excessive amount of lithium ions and leading to metal lithium deposition. The ion source can be installed.

In the second case, the material constituting at least a part of the container by conduction with the positive electrode or the negative electrode dissolves or disappears by oxidation or reductive decomposition according to the potential of the positive electrode or the negative electrode, and supplies the contents into the electrolytic solution. can do. Therefore, capacity degradation can be improved at an arbitrary timing.

In the third case, an effect obtained by combining the first case and the second case is obtained.

From the above, according to the present invention, the supply timing and supply amount of the life extension material are controlled, and not only the initial irreversible capacity is eliminated, but also during storage in a relatively high temperature environment and many times of charge / discharge It is possible to provide a non-aqueous secondary battery and a battery module that can eliminate a capacity reduction due to a side reaction that has progressed with the use of a battery such as a cycle, and that can suppress the occurrence of a new side reaction by supplying an additive.

As a more specific configuration, the lithium ion secondary battery of the present invention includes an electrode group 8 in which electrodes (positive electrode 11 or negative electrode 21) and separators 10 are alternately arranged, and a battery can 1 in which the electrode group 8 is housed. And a life extension material 203 (a general term for the ion supply unit 31 and the electrolyte solution supply unit 34) disposed in the battery can 1, and the electrodes are connected to the life extension material 203 via the switch 40. Yes. By adopting such a structure, it is possible to control the supply timing and supply amount of the life extension material and eliminate the initial irreversible capacity.

Further, the lithium ion secondary battery of the present invention uses the lithium ion ion supply unit 31 as a life extending material. By adopting such a structure, it is possible to recover the lithium ions consumed by the side reaction in the lithium ion secondary battery and recover the capacity reduction.

Moreover, the lithium ion secondary battery of the present invention uses the electrolyte additive supply unit 34 as a life extending material. By adopting such a structure, it is possible to recover the decrease in the electrolyte additive consumed by the side reaction in the lithium ion secondary battery and to recover the capacity decrease.

Further, in the lithium ion secondary battery of the present invention, the electrolytic solution additive supply unit 34 has a protective layer 37 that houses the electrolytic solution additive 35 and a barrier layer 36 that is electrically connected to the electrode and decomposes. ing. With such a structure, the barrier layer 36 can be dissolved or disappeared by being oxidized or reductively decomposed by the potential of the electrode (the positive electrode 11 or the negative electrode 21), and the contents can be supplied into the electrolytic solution. Therefore, capacity deterioration due to a decrease in the electrolyte additive can be improved at an arbitrary timing.

In addition, the lithium ion secondary battery of the present invention has a structure in which a plurality of electrolyte additive supply units 34 are provided, and the connection with the electrode is switched by the switch 40. By adopting such a structure, each electrolyte solution supply unit 34 can be operated at different timings by the switch 40. Therefore, it is possible to supply the electrolytic solution additive 35 a plurality of times, and it is possible to recover the capacity drop due to the decrease of the electrolytic solution additive 35 a plurality of times.
In the lithium secondary battery of the present invention, the life extension material 203 (the ion supply part 31 or the electrolytic solution additive supply part 34) is disposed on the exposed part of the electrode foil (the positive foil 12 or the negative foil 22). By adopting such a structure, the lithium ion secondary battery can be reduced in size while providing a mechanism capable of recovering the capacity drop.

DESCRIPTION OF SYMBOLS 1 Battery can 2 Gasket 3 Upper cover part 5 Positive electrode current collecting plate 6 Negative electrode current collecting plate 7 Axle core 8 Electrode group 11 Positive electrode 12 Positive electrode foil 13 Positive electrode mixture layer 21 Negative electrode 22 Negative electrode foil 23 Negative electrode mixture layer 31 Ion supply part 32 Switch 33 Resistance 34 Electrolyte Additive Supply Unit 35 Electrolyte Additive 36 Barrier Layer 37 Protective Layer 40 Switch 41 Wiring 42 Resistance 100 Charge / Discharge Control Device 101 Battery Information Acquisition Unit 102 Degradation State Determination Unit 103 Switch Operation Determination Unit 104 Control Signal Transmission Part 105 Controller 106 Output part C1 Lithium ion secondary battery

Claims

An electrode group in which electrodes and separators are alternately arranged;
A battery can containing the electrode group;
In a lithium ion secondary battery having a life extension material disposed in the battery can,
The lithium ion secondary battery, wherein the electrode is connected to the life extending member via a switch.
The lithium ion secondary battery according to claim 1,
The life extension material has a lithium ion ion supply part.
The lithium ion secondary battery according to claim 1 or 2,
The lithium ion secondary battery, wherein the life extending material has an electrolyte additive supply unit.
The lithium ion secondary battery according to claim 3,
The lithium ion secondary battery is characterized in that the electrolytic solution additive supply unit includes a protective layer that stores the electrolytic solution additive and a barrier layer that is electrically connected to the electrode and decomposes.
The lithium ion secondary battery according to claim 4,
A lithium ion secondary battery comprising a plurality of the electrolyte additive supply units, each of which is connected to an electrode by the switch.
The lithium ion secondary battery according to claim 4 or 5,
The lithium ion secondary battery, wherein the electrolyte additive is vinylene carbonate.
The lithium ion secondary battery according to any one of claims 2 to 6,
The lithium ion secondary battery is characterized in that the ion supply unit is made of any one of metallic lithium, silicon, tin, or a lithium compound.
The lithium ion secondary battery according to claim 7,
The electrode has a mixture layer coated on the electrode foil, and an electrode foil exposed portion where the electrode foil is exposed,
The lithium ion secondary battery is characterized in that the ion supply unit is disposed in the electrode foil exposed part.