WO2014097906A1

WO2014097906A1 - Electricity storage device manufacturing method and doping bath

Info

Publication number: WO2014097906A1
Application number: PCT/JP2013/082856
Authority: WO
Inventors: 真今野; 平澤　貴久
Original assignee: イビデン株式会社
Priority date: 2012-12-19
Filing date: 2013-12-06
Publication date: 2014-06-26
Also published as: JP2014120701A

Abstract

Provided is an electricity storage device manufacturing method capable of reducing manufacturing process steps requiring a dry environment in comparison with the prior art, and also provided is a doping bath suitable for this manufacturing method. The electricity storage device manufacturing method has a cell preparation step and a pre-doping step. The cell preparation step prepares an electricity storage cell (1) having: an assembled electrode (10) having a separator (103) interposed between a positive electrode (101) and a negative electrode (102); an outer package body (11) housing the assembled electrode (10); and an electrolyte (12) filled in the outer package body (11). The pre-doping step allows, after the cell preparation step, the electrolyte (12) in the outer package body (11) to communicate with another electrolyte (21) in a bath (20) of a doping bath (2) having, in the bath (20), a lithium electrode (22) immersed in the electrolyte (21) to form a liquid communicating state. The pre-doping step also allows the lithium electrode (22) to be electrically connected to the positive electrode (101) or the negative electrode (102), supplies lithium-ions generated at the lithium electrode (22) into the outer package body (11) via an electrolyte (210) forming the liquid communication state, and dopes lithium into the positive electrode (101) or the negative electrode (102).

Description

Storage device manufacturing method and doping tank

The present invention relates to a method for manufacturing an electricity storage device and a doping tank.

In recent years, lithium ion secondary batteries, lithium ion capacitors, and the like have attracted attention as power storage devices used in electric vehicles, hybrid vehicles, storage batteries for power storage, and the like.

In general, a lithium ion secondary battery includes a positive electrode in which a lithium-containing metal oxide is laminated on the surface of a positive electrode current collector, a negative electrode in which a carbon material is laminated on the surface of a negative electrode current collector, and a positive electrode and a negative electrode. The assembled electrode composed of the separator to be sealed has a structure enclosed in the exterior body together with the non-aqueous electrolyte. On the other hand, a lithium ion capacitor generally includes a positive electrode in which a porous carbon material is laminated on the surface of a positive electrode current collector, a negative electrode in which a carbon material doped with lithium is laminated on the surface of a negative electrode current collector, and a positive electrode and a negative electrode. An assembled electrode composed of a separator interposed between the electrodes and the non-aqueous electrolyte is enclosed in the outer package.

In the lithium ion secondary battery, among the lithium doped in the negative electrode with lithium de-doping from the positive electrode in the initial charging process, the lithium that remains in the negative electrode without being de-doped from the negative electrode in the discharging process is left. Exists. This is because lithium is taken into a film called SEI (solid electrolyte interface) formed on the negative electrode surface by the reaction with the electrolytic solution, and the lithium taken into the film does not participate in the subsequent battery reaction. Therefore, for example, Patent Document 1 proposes a technique of pre-doping the negative electrode in advance with the amount of lithium remaining in the negative electrode without being dedoped when the negative electrode is manufactured.

On the other hand, since a lithium ion capacitor does not use a material containing lithium as an electrode unlike a lithium ion secondary battery, lithium is pre-doped to ensure the lithium. As the pre-doping technique, for example, Patent Document 2 discloses a technique in which an assembled electrode is immersed in a doping tank that exists separately from an exterior body in which a lithium electrode is immersed in an electrolytic solution, and lithium is pre-doped in a negative electrode. Has been. In addition, Patent Document 3 discloses a technique in which a lithium electrode is disposed in an exterior body in addition to the assembled electrode and the electrolytic solution, and the negative electrode is pre-doped with lithium in the exterior body.

JP 7-235330 A JP 2012-44137 A JP 2008-124227 A

However, the conventional methods for manufacturing power storage devices such as lithium ion secondary batteries and lithium ion capacitors using lithium have the following problems. That is, metallic lithium hardly changes in dry air, but when there is moisture, it reacts with nitrogen at room temperature to produce lithium nitride. Therefore, once metallic lithium is used in each manufacturing process of the electricity storage device, the subsequent manufacturing process needs to be performed in a dry environment with a low dew point. For example, as described above, when the assembled electrode is immersed in a doping tank that is separate from the exterior body and lithium is doped into the negative electrode, the subsequent manufacturing process must be performed in a dry environment. Therefore, in order to form a dry environment, a large-scale process change is forced on each existing manufacturing process.

Note that, as described above, the method of arranging the lithium electrode in the exterior body of the electricity storage device and pre-doping lithium into the negative electrode in the exterior body takes time for pre-doping. Further, in this method, a large number of through holes are essential for the positive electrode and the negative electrode in order to ensure sufficient movement of lithium ions, and the cost of the electricity storage device increases due to the formation processing of the through holes.

The present invention has been made in view of the above circumstances, and a method for manufacturing an electricity storage device capable of reducing the number of manufacturing steps that require a dry environment as compared with the conventional one, and a doping tank suitable for this manufacturing method. It was obtained by trying to provide.

The method for producing an electricity storage device of the present invention includes an assembled electrode including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, an exterior body that houses the assembled electrode, and an electrolyte solution that fills the exterior body A cell preparation step of preparing a storage cell having:
After the cell preparation step, the electrolyte solution in the tank of the doping tank having the lithium electrode immersed in the same type of electrolyte as the electrolyte solution in the outer package and the electrolyte solution in the outer package are passed through. The lithium electrode and the negative electrode or the positive electrode are electrically connected to each other, and the lithium ions generated at the lithium electrode are passed through the electrolytic solution forming the liquid flow state. A pre-doping step of supplying lithium into the negative electrode or the positive electrode;
(Claim 1).

The doping tank of the present invention includes the negative electrode or the positive electrode of a storage cell having at least an assembled electrode including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an exterior body that houses the assembled electrode. A doping bath used to dope lithium into
A tank containing an electrolyte solution;
A lithium electrode immersed in the electrolyte,
A connecting pipe configured so that one end communicates with the inside of the tank and the other end communicates with the inside of the exterior body in the storage cell;
A connection circuit having one end electrically connected to the lithium electrode and the other end electrically connectable to the negative electrode or the positive electrode;
(Claim 7).

The manufacturing method of the electricity storage device includes the pre-doping step after the cell preparation step. That is, in the method for manufacturing the electricity storage device, after the assembled electrode is accommodated in the exterior body, lithium ions are supplied into the exterior body from a doping tank that exists separately from the exterior body of the electrical storage cell, and lithium is pre-doped into the negative electrode or the positive electrode . For this reason, in the method for manufacturing the electricity storage device, the pre-doping process, which is a subsequent process of the cell preparation process, may be at least in a dry environment, and the number of manufacturing processes that require a dry environment can be reduced as compared with the conventional method.

The doping tank has the above configuration. Therefore, the doping tank is connected to the exterior body by connecting the other end of the connection pipe to allow the electrolyte solution in the doping tank tank and the electrolyte solution in the exterior body to pass through the connection pipe. can do. Therefore, the doping tank can supply lithium ions generated from the lithium electrode from the doping tank to the exterior body through the electrolytic solution that forms the liquid passing state in the connection pipe. Moreover, the said doping tank can supply an electron to a negative electrode or a positive electrode by electrically connecting the other end of a connection circuit to a negative electrode or a positive electrode. Therefore, the doping tank can be suitably used for manufacturing the electricity storage device.

Therefore, according to the present invention, it is possible to provide a method for manufacturing an electricity storage device capable of reducing the number of manufacturing steps that require a dry environment as compared with the conventional case, and a doping bath suitable for this manufacturing method.

It is explanatory drawing for demonstrating the manufacturing method and doping tank of the electrical storage device of Example 1. FIG. It is another explanatory drawing for demonstrating the manufacturing method and doping tank of the electrical storage device of Example 1. FIG. FIG. 3 is an explanatory diagram for explaining an electricity storage device according to the method for manufacturing an electricity storage device of Example 1. It is explanatory drawing for demonstrating the manufacturing method and doping tank of the electrical storage device of Example 2. FIG.

First, a method for manufacturing the power storage device will be described. In addition, the description of the doping tank mentioned later can be referred as needed.

The method for manufacturing an electricity storage device is a method for producing an electricity storage device using lithium. Specifically, the electricity storage device is not particularly limited as long as it utilizes a redox reaction of lithium. More specifically, the power storage device is a lithium ion secondary battery (hereinafter sometimes abbreviated as “LiB”) or a lithium ion capacitor (hereinafter sometimes abbreviated as “LiC”). (Claim 6).

In the case where the electricity storage device is LiB, in the initial charging process, among the lithium doped in the negative electrode accompanied by the dedoping of lithium from the positive electrode, the lithium remains in the negative electrode without being dedoped from the negative electrode in the subsequent discharging process. A minute amount of lithium can be pre-doped into the negative electrode in advance. Therefore, in this case, it is possible to reduce the number of manufacturing steps that require a dry environment, and it is possible to obtain LiB excellent in charge / discharge cycle characteristics.

On the other hand, when the electricity storage device is LiC, lithium ions can be sufficiently supplied into the exterior body from a doping tank existing separately from the exterior body after accommodating the assembled electrode in the exterior body. Therefore, in this case, it is not necessary to previously form a large number of through-holes in the positive electrode and the negative electrode, as compared with the conventional manufacturing method in which lithium ions are supplied from the lithium electrode arranged in the exterior body and the negative electrode or the positive electrode is doped with lithium. Therefore, in this case, it is possible to reduce the number of manufacturing processes that require a dry environment, and it is possible to eliminate the formation of positive and negative electrode holes, thereby reducing the manufacturing cost of the electricity storage device. it can. In this case, an electricity storage device having a high degree of freedom in shape of the positive electrode and the negative electrode can be obtained.

In the cell preparation step, the assembled electrode includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. Specifically, the assembled electrode can be composed of a laminate in which positive and negative electrodes are alternately laminated via separators. Examples of the method for laminating the laminated body include a winding method and a zigzag folding method.

The positive electrode can be configured to have a positive electrode current collector and a positive electrode active material layer laminated on the surface of the positive electrode current collector. The positive electrode current collector preferably has no through hole penetrating the front and back surfaces. Specific examples of the material of the positive electrode current collector include aluminum (including an alloy, hereinafter omitted), stainless steel, and the like. The positive electrode active material is not particularly limited as long as it can be doped and dedoped with lithium. The positive electrode active material may capture and capture lithium ions as a compound, or may capture lithium ions in an electric double layer formed on the surface, such as activated carbon. Examples of the former positive electrode active material include lithium-containing metal oxides, and specifically, for example, LiVO ₂ , LiCrO ₂ , LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiFePO ₄ , LiCoVO _4. LiCoMnO ₄ , Li ₂ FeMn ₃ O ₈ , Li ₂ FePO ₄ F, LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ , Li (Li _a Ni _x Mn _y Co _z ) and the like can be exemplified. . These positive electrode active materials can be used for production of LiB. Specific examples of the latter positive electrode active material include porous carbon materials such as activated carbon and polyacene carbon materials. These positive electrode active materials can be used for the production of LiC.

Specifically, the negative electrode can be configured to have a negative electrode current collector and a negative electrode active material layer laminated on the surface of the negative electrode current collector. The negative electrode current collector preferably has no through hole penetrating the front and back surfaces. Specific examples of the material for the negative electrode current collector include copper (including an alloy, hereinafter omitted), stainless steel, and the like. The negative electrode active material is not particularly limited as long as it can be doped and dedoped with lithium. Specific examples of the negative electrode active material include carbon materials such as graphite and amorphous carbon, lithium titanate, and the like. Of these, graphite is particularly suitable because it is readily available and has a large capacity.

The separator is not particularly limited as long as it can insulate between the positive electrode and the negative electrode and can be impregnated with the electrolytic solution. Specific examples of the separator include an insulating porous film made of a polymer such as polyolefin, tetrafluoroethylene, polyimide, polyethylene terephthalate, and nylon.

Specifically, the exterior body used in the cell preparation step can accommodate the assembled electrode and can be filled with the electrolyte, and can be configured to allow communication between the interior of the exterior body and the exterior of the exterior body. Specifically, the exterior body can be formed into a bag shape, a cylindrical shape, a square shape, or the like using, for example, a laminate film, a metal material such as aluminum or iron, a resin material, ceramics, or the like.

In the cell preparation process, the method of filling the exterior body with the electrolytic solution is not particularly limited. For example, the electrolytic solution can be injected after housing the assembled electrode in the exterior body, or the assembled electrode can be accommodated after injecting the electrolytic solution into the exterior body. Further, the electrolytic solution in the exterior body can be supplied from the doping tank, or can be supplied from an electrolytic solution supply source different from the doping tank. When the electrolytic solution in the exterior body is supplied from the doping tank, it is excellent in continuity with the pre-doping step, which can contribute to improvement in productivity.

As the electrolytic solution, a non-aqueous electrolytic solution can be used. Specific examples of the electrolyte include organic solvents such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, acetonitrile, dimethoxyethane, tetrahydrofuran, dioxofuran, methylene chloride, and sulfolane. it can. The lithium salt to be contained in the electrolyte, specifically, for _example, and the like can be exemplified salts with _{_{_{LiBF 4, LiClO 4, LiPF 6}}} , LiAsF 6, LiSbF 6 high anion electron withdrawing like.

In the pre-doping step after the cell preparation step, the electrolyte solution in the doping tank in which the lithium electrode is immersed in the same type of electrolyte solution as the electrolyte in the exterior body and the electrolyte solution in the exterior body are allowed to pass through and the liquid passing state is changed. After the formation, the electrical connection state between the lithium electrode and the negative electrode or the positive electrode may be ensured, or the liquid connection state may be formed after the electrical connection state is ensured. . Or you may make it ensure the said liquid flow state and the said electrical connection state simultaneously. In addition, by forming the above-described liquid passing state, the electrolyte in the doping tank and the electrolyte in the exterior body can continuously communicate, and lithium ions can freely move from the doping tank to the exterior body. become. Further, “the same kind” of the electrolytic solution in the exterior body and the electrolytic solution in the doping tank means that the main components occupying 50% by mass or more of the components of the electrolytic solution are the same.

In the method for manufacturing an electricity storage device, the exterior body has a communication hole that communicates the inside and the exterior of the exterior body at a position facing the end of the assembled electrode. In the pre-doping step, the communication hole and the doping tank are provided. The inside of the tank may be in a state of communicating with each other via a connecting pipe (claim 2).

In this case, the electrolyte solution in the doping tank existing separately from the exterior body of the storage cell and the electrolyte solution in the exterior body can be relatively easily passed through the connecting pipe to obtain a liquid-permeable state. it can. Therefore, lithium ions can freely move through the electrolytic solution that forms the liquid passing state in the connecting pipe. Therefore, in this case, it is possible to ensure that lithium ions generated at the lithium electrode move to the electrolytic solution in the exterior body via the connection pipe and the communication hole. The communication hole is formed at a position facing the end of the assembled electrode. Therefore, in this case, lithium ions introduced into the exterior body from the communication hole can easily enter the assembled electrode from the end of the assembled electrode through the gap between the electrodes or the porous separator, and can be efficiently doped. It becomes possible. The “end portion of the assembled electrode” means a portion where the positive electrode and / or the negative electrode and the separator are exposed. Further, the exterior body can have one or more communication holes, and the connection pipe can be provided in accordance with the number of communication holes of the exterior body.

In the pre-doping step, the lithium electrode and the negative electrode or the positive electrode can be electrically connected by a short circuit or can be electrically connected via an external power source (claims). 3).

The latter method using an external power source can forcibly generate a potential difference between the lithium electrode and the negative electrode or the positive electrode by the external power source, so that ionization by oxidation of lithium at the lithium electrode and Reduction of lithium ions can be promoted. Therefore, the latter method using an external power source can promote doping of lithium into the negative electrode or the positive electrode as compared with the former method using a short circuit. In the latter method using an external power supply, an external power supply may be connected so that a current can flow from the negative electrode or the positive electrode toward the lithium electrode.

The pre-doping step may include one of the following two procedures so that the negative electrode is finally doped with lithium. That is, the pre-doping step can include a procedure in which the lithium electrode and the negative electrode are electrically connected, and the negative electrode is doped with lithium.

In this case, since the negative electrode is directly doped with lithium, the pre-doping process can be made relatively short, and the productivity of the electricity storage device is excellent.

Further, instead of the above procedure, the pre-doping step is performed by doping lithium in the positive electrode with the lithium electrode and the positive electrode electrically connected, and then charging with the positive electrode and the negative electrode electrically connected. A step of doping the negative electrode with the lithium doped in the positive electrode can be included (claim 5).

In this case, since the negative electrode is once doped with lithium through the positive electrode, the number of times lithium is transferred is increased as compared with the case where the negative electrode is directly doped, so that lithium can diffuse and be uniformly doped. In addition, when applied to a lithium ion secondary battery, the positive electrode can be sufficiently doped with lithium by charging once and reducing the positive electrode lithium before doping.

The manufacturing method of the electricity storage device may have a sealing step of releasing the liquid passing state and the electrical connection state after the pre-doping step and sealing the outer package. In this case, since the exterior body is sealed after the pre-doping step, the decomposition gas generated in the pre-doping step can be removed from the inside of the exterior body. When the connection pipe is connected to the communication hole of the exterior body, the communication hole and the connection pipe may be separated and the communication hole may be sealed. When the communication hole portion is made of metal or the like, sealing can be performed by caulking, welding, or the like. Further, when the communicating hole portion is made of a resin such as a laminate film, sealing can be performed by welding or the like. In addition, sealing can be performed by press-fitting or adhering a plug into the communication hole regardless of the material of the communication hole portion.

Next, the doping tank will be described. In addition, the description of the manufacturing method of the electrical storage device mentioned above can be referred as needed.

The doping tank can be suitably used in the above-described method for manufacturing an electricity storage device. In the doping tank, the lithium electrode may be entirely immersed in the electrolytic solution, or may be partially immersed in the electrolytic solution. The shape of the lithium electrode is not particularly limited, and may be various shapes such as a block shape, a rod shape, and a foil shape. Further, the arrangement of the lithium electrode is not particularly limited. For example, the lithium electrode may be disposed on the bottom surface of the doping tank through a metal tray or the like, or may be disposed on the inner wall surface of the doping tank. Can do.

It is preferable that one end of the connecting pipe is disposed below the liquid level of the electrolytic solution in the tank. In this case, a pressure difference is generated between the inside of the exterior body and the inside of the tank, for example, by making the inside of the exterior body into a vacuum state, and the electrolyte solution is transferred from the doping tank to the exterior body using this pressure difference. Can be supplied. The material of the connecting pipe is not particularly limited, and various types of resins and metals can be used. Among them, since the connecting pipe using a resin is insulative, lithium and the like are hardly deposited due to a potential difference generated in the electrolytic solution, and can be suitably used.

The connection circuit can include the external power source described above. The external power source can be configured to be able to supply a constant current and / or a constant potential between, for example, a negative electrode or a positive electrode and a lithium electrode.

Hereinafter, the manufacturing method and the doping tank of the electricity storage device of the examples will be described with reference to the drawings.

(Example 1)
A manufacturing method and a doping tank of the electricity storage device of Example 1 will be described with reference to FIGS. For convenience of explanation, the doping tank of Example 1 will be described first.

As shown in FIGS. 1 and 2, the doping tank 2 of this example accommodates the assembled electrode 10 including the positive electrode 101, the negative electrode 102, the separator 103 interposed between the positive electrode 101 and the negative electrode 102, and the assembled electrode 10. It is used to dope lithium into the negative electrode 102 or the positive electrode 101 of the electricity storage cell 1 having the outer package 11 that performs the above operation.

The doping tank 2 includes a tank 20 that stores the electrolytic solution 21, a lithium electrode 22 that is immersed in the electrolytic solution 21, a connection tube 24, and a connection circuit 25. In this example, the lithium electrode 22 is all immersed in the electrolytic solution 21.

The connection pipe 24 is configured such that one end communicates with the inside of the tank 20 and the other end communicates with the inside of the outer package 11 in the storage cell 1. In this example, the connecting pipe 24 is made of resin. One end of the connection pipe 24 is inserted into the tank 20 and is disposed below the liquid surface of the electrolytic solution 21 in the tank 20. The other end of the connection pipe 24 extends toward the storage cell 1 and can be connected to a communication hole 113 of the exterior body 11 described later. In the middle of the connecting pipe 24, a valve 241 is provided that can be opened or closed to open or close the pipe.

The connection circuit 25 is configured such that one end is electrically connected to the lithium electrode 22 and the other end is electrically connectable to the negative electrode 102 or the positive electrode 101. In this example, the lithium electrode 22 is placed on a metal tray 221 placed on the bottom surface in the tank 20, and a lead wire 222 extending from the tray 221 is connected to an external terminal 23 provided outside the tank 20. Electrically connected. One end of the connection circuit 25 is electrically connected to the lithium electrode 22 via the external terminal 23. On the other hand, the other end of the connection circuit 25 is configured to be electrically connectable to the negative electrode 102 or the positive electrode 101 via the negative electrode terminal 14 or the positive electrode terminal 13 of the storage cell 1. An external power source 251 is provided in the middle of the connection circuit 25, and the lithium electrode 22 and the negative electrode 102 or the positive electrode 101 are configured to be electrically connected via the external power source 251. Note that the external power supply 251 is connected so that a current can flow from the negative electrode 102 or the positive electrode 101 toward the lithium electrode 22 when the switch is turned on.

Next, a method for manufacturing the electricity storage device of Example 1 will be described.

The manufacturing method of the electricity storage device of this example includes a cell preparation process and a pre-doping process.

As shown in FIG. 1 and FIG. 2, the cell preparation step includes an assembled electrode 10 including a positive electrode 101, a negative electrode 102, a separator 103 interposed between the positive electrode 101 and the negative electrode 102, and an outer package housing the assembled electrode 10. 11 and a step of preparing a storage cell 1 having an electrolyte solution 12 filling the exterior body 11.

In this example, the assembled electrode 10 is formed of a laminated body in which the positive electrodes 101 and the negative electrodes 102 are alternately stacked via the separator 103 and wound. The positive electrode 101 has a positive electrode current collector (not shown) and a positive electrode active material layer (not shown) including a lithium-containing metal oxide laminated on the surface of the positive electrode current collector. The positive electrode active material layer is formed by applying a paste containing a porous carbon material and a binder to the surface of the positive electrode current collector, drying it, and pressing it. The negative electrode 102 has a negative electrode current collector (not shown) and a negative electrode active material layer (not shown) containing a carbon material laminated on the surface of the negative electrode current collector. The negative electrode active material layer is formed by applying a paste containing a carbon material and a binder to the surface of the negative electrode current collector, drying, and pressing. The separator 103 is made of a porous resin film. Neither the positive electrode 101 nor the negative electrode 102 is subjected to a through hole forming process that penetrates the front and back surfaces. The positive electrode 101 has a positive electrode tab (not shown). Each positive electrode is joined between each positive electrode tab by ultrasonic welding. The joined positive electrode tab is electrically connected to a positive electrode terminal 13 provided outside the exterior body 11. Similarly, the negative electrode 102 has a negative electrode tab (not shown). Each negative electrode is joined between each negative electrode tab by ultrasonic welding. The bonded negative electrode tab is electrically connected to a negative electrode terminal 14 provided outside the exterior body 11.

The exterior body 11 has a bottomed metallic cylinder portion 111 and a metallic lid body 112 attached by caulking after the assembled electrode 10 is accommodated therein. The lid body 112 has a communication hole 113 that allows the interior of the exterior body 11 to communicate with the exterior of the exterior body 11. It is possible to form the exterior body 11 without using the lid body 112, and in this case, the communication hole 113 may be formed in any part of the exterior body 11 other than the lid body 113.

In this example, after the assembled electrode 10 is accommodated in the cylindrical portion 111 of the exterior body 11, the lid body 112 is attached to the upper portion of the cylindrical portion 111 by caulking, and the other end of the connection pipe 24 of the doping tank 2 is connected to the communication hole 113. Connecting. Thereby, the communication hole 113 and the inside of the tank 20 of the doping tank 2 are communicated with each other via the connection pipe 24. Then, the non-aqueous electrolyte solution 21 is injected from the doping tank 2 through the communication hole 113, and the interior of the outer package 11 is filled with the electrolyte solution 12. In this example, specifically, as shown in FIG. 1, the vacuum pump 3 is connected to the communication hole 113 of the storage cell 1, the valve 31 is opened, and the inside of the exterior body 11 is deaerated under reduced pressure. In FIG. 1, the valve 241 of the connecting pipe 24 is closed. The external power supply 251 is off. Thereafter, as shown in FIG. 2, the valve 31 on the vacuum pump 3 side is closed and the valve 241 of the connecting pipe 24 is opened, and electrolysis is performed using the pressure difference between the inside of the exterior body 11 and the inside of the tank 20 of the doping tank 2. The liquid 12 is injected. In the cell preparation step, the storage cell 1 is prepared as described above.

In the pre-doping step, after the cell preparation step, the electrolytic solution 21 in the bath 20 of the doping bath 2 having the lithium electrode 22 immersed in the electrolytic solution 21 of the same type as the electrolytic solution 12 in the outer package 11 in the bath 20 The electrolytic solution 12 in the outer package 11 is passed through to form a liquid passing state, and the lithium electrode 22 and the negative electrode 102 or the positive electrode 101 are electrically connected, and lithium ions generated at the lithium electrode 22 are generated. In this step, the negative electrode 102 or the positive electrode 101 is doped with lithium by being supplied into the outer package 11 through the electrolytic solution 210 forming the liquid passing state.

In this example, after injecting the electrolyte solution 21 from the tank 20 of the doping tank 2 into the outer package 11 in the cell preparation process, the pre-doping process is subsequently performed in a dry environment. Therefore, when the exterior body 11 is filled with the electrolyte solution 12 by the injection of the electrolyte solution 21, the electrolyte solution 21 in the tank 20 of the doping tank 2 and the electrolyte solution 12 in the exterior body 11 are connected to the connection pipe 24. The liquid is passed through the electrolytic solution 210 inside. Further, in this example, after the liquid passing state is formed, the external power source 251 of the connection circuit 25 connected to the negative electrode 14 is turned on, and the lithium electrode 22 and the negative electrode 102 are electrically connected. As a result, lithium ions are generated at the lithium electrode 22, and the generated lithium ions are supplied from the tank 20 of the doping tank 2 to the electrolyte solution 12 in the outer package 11 via the connection pipe 24 and the communication hole 113 (transportation / transportation). Electrophoresis etc.). Electrons are supplied to the negative electrode 14. As a result, in this example, the negative electrode 102 is doped with lithium. In the pre-doping step, the negative electrode 102 is doped with lithium as described above.

The manufacturing method of the electricity storage device of this example further includes a sealing step of releasing the liquid passing state and the electrical connection state and sealing the outer package 11 after the pre-doping step. In this example, specifically, after the communication hole 113 of the outer package 11 and the connection pipe 24 of the doping tank 2 are separated in a dry environment, the communication hole 113 is sealed by welding.

As described above, as shown in FIG. 3, the assembled electrode 10 including the positive electrode 101, the negative electrode 102, the separator 103 interposed between the positive electrode 101 and the negative electrode 102, the exterior body 11 that houses the assembled electrode 10, and the exterior body 11 is obtained, and the storage device 4 (in this example, a lithium ion secondary battery) in which the negative electrode 102 is doped with lithium is obtained.

Next, the manufacturing method of the electricity storage device of this example and the function and effect of the doping tank will be described.

The manufacturing method of the electricity storage device of this example has a pre-doping process after the cell preparation process. That is, in the method of manufacturing the electricity storage device of this example, after the assembled electrode is accommodated in the exterior body, lithium ions are supplied from the doping tank that exists separately from the exterior body of the electricity storage cell, and lithium is pre-doped to the negative electrode. . Therefore, the manufacturing method of the electrical storage device of this example should just make the pre dope process and the sealing process which seals an exterior body which are a post process of a cell preparation process in a dry environment. Therefore, compared to the conventional manufacturing method in which the assembled electrode is immersed in a doping vessel that is separate from the outer package in which the lithium electrode is immersed in the electrolytic solution, and the negative electrode is doped with lithium, the number of manufacturing processes requiring a dry environment is reduced. can do. The sealing process is usually performed in a dry environment even in the conventional manufacturing method.

Moreover, the doping tank has the above configuration. Therefore, in the doping tank, the other end of the connection pipe is connected to the exterior body, so that the electrolyte solution in the doping tank tank and the electrolyte solution in the exterior body are passed through the connection pipe to be in a liquid-permeable state. be able to. Therefore, the doping tank can supply lithium ions generated from the lithium electrode from the inside of the doping tank to the exterior body through the electrolytic solution that forms the liquid passing state in the connection pipe. Further, the doping tank can supply electrons to the negative electrode by electrically connecting the other end of the connection circuit to the negative electrode. Therefore, the doping tank can be suitably used for manufacturing the electricity storage device of this example.

Therefore, according to Example 1, it is possible to provide a method for manufacturing an electricity storage device capable of reducing the number of manufacturing steps that require a dry environment as compared with the conventional case, and a doping tank suitable for this manufacturing method.

(Example 2)
The power storage device manufacturing method of Example 2 is the same as that of Example 1 in that the porous carbon material as the positive electrode active material is a porous carbon material in the cell preparation step in the power storage device manufacturing method of Example 1. It is different from the device manufacturing method. Further, in the method of manufacturing the electricity storage device of Example 2, in the pre-doping step, after forming the liquid passing state, the lithium electrode 22 and the positive electrode 101 are electrically connected by a short circuit without using the external power source 251. After the lithium is doped into the positive electrode 101, charging is performed with the positive electrode 101 and the negative electrode 102 being electrically connected to each other, whereby the negative electrode 102 is doped with lithium doped into the positive electrode 101. The manufacturing method is different. Others are substantially the same as the manufacturing method of the electrical storage device of Example 1.

Moreover, the doping tank 2 of Example 2 is different from the doping tank 2 of Example 1 in that it further includes an electrolyte reserve tank 26 that replenishes the electrolyte 21 in the tank 20 as shown in FIG. Yes. Others are substantially the same as the doping tank 2 of Example 1.

According to the method for manufacturing an electricity storage device of Example 2, an assembled electrode including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, an exterior body that accommodates the assembled electrode, and an electrolyte that fills the exterior body Thus, an electricity storage device (lithium ion capacitor in this example) in which the negative electrode is doped with lithium is obtained.

In the case of Example 2, as in Example 1, a method for manufacturing an electricity storage device capable of reducing the number of manufacturing steps that require a dry environment as compared to the conventional method and a doping bath suitable for this manufacturing method are provided. be able to.

Further, in the doping tank of Example 2, since the electrolyte preliminary tank is connected to the tank, the electrolyte can be replenished in the tank, and the liquid level of the electrolyte in the tank can be easily maintained. Therefore, the doping tank of Example 2 has an advantage that it is easy to maintain the above-mentioned liquid passing state, and to ensure the movement of lithium ions from the inside of the tank to the exterior body. The replenishment of the electrolytic solution from the electrolytic solution preliminary tank into the tank can be performed by taking a balance using a pressure difference between the electrolytic solution preliminary tank and the tank. In other respects, the same effects as the doping tank of the first embodiment can be obtained.

(Experimental example 1)
A paste containing LiCoO ₂ and a binder was applied in a range of 40 mm × 40 mm to a thickness of 50 μm on the surface of an aluminum alloy foil having a thickness of 20 μm and dried to form a positive electrode. Further, a paste containing graphite and a binder was applied in a range of 40 mm × 40 mm to a thickness of 50 μm on the surface of a copper foil having a thickness of 20 μm, and dried to form a negative electrode. Subsequently, the laminated body which laminated | stacked the obtained positive electrode and negative electrode alternately via the 25-micrometer-thick porous polypropylene film was formed. The positive electrode tabs and the negative electrode tabs in the laminate were joined together by ultrasonic welding. Next, the laminated body was sealed in a bottomed cylindrical portion having a communication hole and made of resin, and a cover was formed to form an exterior body. In addition, the positive electrode terminal electrically connected to the welded positive electrode tab and the negative electrode terminal electrically connected to the welded negative electrode tab were formed outside the exterior body. Next, a vacuum pump and a connecting pipe of a doping tank having the configuration shown in FIG. 1 were connected to the communication hole of the obtained exterior body. Next, the inside of the exterior body was degassed by a vacuum pump, and at least three kinds of electrolytes in the tank (ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate were mixed via a connecting pipe) 1 mol / L of a LiPF ₆ or LiBF ₄ lithium salt dissolved in a solvent) was injected into the exterior body by a differential pressure. This prepared the electrical storage cell.

In this example, after the electrolyte solution is injected, the electrolyte tube in the doping vessel and the electrolyte solution in the storage cell are in the connection tube by keeping the connecting tube of the doping vessel connected to the communication hole. The liquid was passed through the electrolytic solution. Subsequently, the external power supply of the connection circuit of the doping tank connected to the negative electrode of the electricity storage cell was turned on to electrically connect the lithium electrode and the negative electrode. In this case, a current was applied from the negative electrode to the lithium electrode at a rate of 0.05 C to 1 C at a rate of 0.1 A / cm ² or less. Thereby, the lithium ion produced | generated by the lithium electrode was supplied from the inside of a doping tank into the electrical storage cell, and lithium for the irreversible capacity | capacitance which is 20% of a negative electrode capacity | capacitance was doped to the negative electrode directly. The pre-doping step was performed in a dry environment controlled at a dew point of −35 to −65 ° C. dp.

Next, in the dry environment, the communication cell communication hole and the doping tank connecting pipe were separated. Subsequently, the communication hole part of the electrical storage cell was thermally welded and sealed. Thus, a lithium ion secondary battery as an electricity storage device was obtained.

(Experimental example 2)
Other than the point that a positive electrode was formed by applying a paste containing a porous carbon material and a binder to the surface of a 20 μm thick aluminum alloy foil at a thickness of 100 μm (twice the capacity of graphite) in a range of 40 mm × 40 mm and drying. In the same manner as in Experimental Example 1, the negative electrode was directly doped with lithium to obtain a lithium ion capacitor as an electricity storage device.

Although the embodiments have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Storage cell 10 Assembly electrode 101 Positive electrode 102 Negative electrode 103 Separator 11 Exterior body 12 Electrolytic solution 2 Doping tank 20 Tank 21 Electrolytic solution 210 Electrolytic solution 22 Lithium electrode 24 Connection pipe 25 Connection circuit

Claims

Cell preparation for preparing a storage cell having an assembled electrode including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, an exterior body that accommodates the assembled electrode, and an electrolyte solution that fills the exterior body Process,
After the cell preparation step, the electrolyte solution in the tank of the doping tank having the lithium electrode immersed in the same type of electrolyte as the electrolyte solution in the outer package and the electrolyte solution in the outer package are passed through. The lithium electrode and the negative electrode or the positive electrode are electrically connected to each other, and the lithium ions generated at the lithium electrode are passed through the electrolytic solution forming the liquid flow state. A pre-doping step of supplying lithium into the negative electrode or the positive electrode;
The manufacturing method of the electrical storage device characterized by having.
It is a manufacturing method of the electrical storage device according to claim 1,
The exterior body has a communication hole that communicates the inside and the exterior of the exterior body at a position facing the end of the assembled electrode,
In the pre-doping step, the communication hole and the inside of the doping tank are in communication with each other via a connecting pipe.
It is a manufacturing method of the electrical storage device according to claim 1 or 2,
In the pre-doping step, the lithium electrode and the negative electrode or the positive electrode are electrically connected via an external power source.
A method for manufacturing an electricity storage device according to any one of claims 1 to 3,
The method of manufacturing an electricity storage device, wherein the pre-doping step includes a step of electrically connecting the lithium electrode and the negative electrode and doping the negative electrode with the lithium.
A method for manufacturing an electricity storage device according to any one of claims 1 to 3,
In the pre-doping step, the lithium electrode and the positive electrode are electrically connected and the lithium is doped into the positive electrode, and then the positive electrode and the negative electrode are electrically connected to perform charging. The manufacturing method of the electrical storage device characterized by including the procedure which dopes the said negative electrode doped to the said positive electrode to the said negative electrode.
A method for manufacturing an electricity storage device according to any one of claims 1 to 5,
The method for manufacturing an electricity storage device, wherein the electricity storage device is a lithium ion secondary battery or a lithium ion capacitor.
In order to dope lithium into the negative electrode or the positive electrode of the storage cell, which has at least an assembled electrode including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an exterior body that accommodates the assembled electrode A doping bath used,
A tank containing an electrolyte solution;
A lithium electrode immersed in the electrolyte,
A connecting pipe configured so that one end communicates with the inside of the tank and the other end communicates with the inside of the exterior body in the storage cell;
A connection circuit having one end electrically connected to the lithium electrode and the other end electrically connectable to the negative electrode or the positive electrode;
A doping tank characterized by comprising: