JP5172719B2 - Electric storage device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric storage device with high output, excellent in vibration resistance. <P>SOLUTION: The electric storage device 11 includes a rectangular metal can 21, a first electrode 31, a second electrode 41, and a separator 46. A laminated electrode group 51 is constituted by laminating the first electrode 31, the second electrode 41 and the separator 46, and housed in the metal can 21. A conductive metal-made connecting plate 52 having an area equal to that of a bottom part 23 of the can 21 is welded to the inner surface of the bottom part 23. A cylindrical part 22 of the can 21 includes a swollen part 24 on a surface which is not located in the thickness direction of the laminated electrode group 51. A holding member 61 formed of an insulating rigid body, which holds the electrode group 51 while pressing the connecting plate 52, is disposed within an internal space 25 of the swollen part 24. The first electrode 31 is connected to the connecting plate 52. A conductive metal-made lid body 54 is fixed to an opening of the can 21 through a gasket 53. The second electrode 31 is connected to the lid body 54. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a large-capacity, high-voltage storage device and a method for manufacturing the same.

  Energy storage systems such as load leveling devices such as photovoltaic power generation and wind power generation, instantaneous voltage drop countermeasure devices for electronic devices such as computers, and energy regeneration devices for electric vehicles and hybrid cars have a large energy capacity. In addition, an electricity storage device capable of rapid charge / discharge is required. In recent years, non-aqueous power storage devices have attracted attention as a kind of power storage devices that are promising for such applications (see, for example, Patent Document 1). In particular, non-aqueous power storage devices used for transport aircraft and the like are required to have vibration resistance in addition to high output performance.

  Currently, the mainstream of this type of power storage device is a capacitor using an electric double layer function (so-called electric double layer capacitor). However, since the electric double layer capacitor has a small capacity and a low voltage, there is a problem that the whole apparatus becomes large when it is intended to realize a large capacity and a high voltage. Therefore, a lithium pre-doped lithium ion capacitor has been proposed as a new electricity storage device that can solve this problem. In this type of lithium ion capacitor, a negative electrode made of a material capable of inserting and extracting lithium is used, and the negative electrode potential is lowered by pre-doping lithium into the negative electrode. As a result, it is possible to obtain a high voltage as a battery, thereby increasing the energy capacity.

  As a lithium ion capacitor, it was equipped with the laminated electrode group which laminated | stacked a flat positive electrode, a negative electrode, and a separator, or the winding electrode group formed by winding a positive electrode, a negative electrode, and a separator in roll shape. Things are known in the art. Moreover, as a container which accommodates a laminated electrode group and a wound electrode group, a flat aluminum laminated container, a cylindrical metal container, etc. are conventionally used (for example, refer patent document 1, 2).

JP 2000-90892 A JP 2006-12702 A

  In the case of a lithium ion capacitor in which a laminated electrode group is accommodated in an aluminum laminated container, the laminated electrode group formed in a flat plate shape or a rectangular parallelepiped shape can be accommodated in the container without any particular problem. It is also possible to thicken the external lead conductors such as the body and the negative electrode current collector. Therefore, there is an advantage that a structure suitable for high output use can be obtained. However, since the aluminum laminate container is soft and not rigid, it cannot be reliably fixed to the device, and it is difficult to impart excellent vibration resistance.

  In addition, in the case of a lithium ion capacitor in which the wound electrode group is housed in a metal container, the container has a certain degree of rigidity, so that it can be securely fixed to the device and has a structure suitable for vibration resistance applications. There is an advantage that can be. However, since the wound electrode group cannot be formed in a flat plate shape or a rectangular parallelepiped shape, it is not possible to form the conductors for external lead such as the positive electrode current collector and the negative electrode current collector thick, and excellent high output performance. There is a drawback that it is difficult to impart. More specifically, when a metal container having an opening at one end is employed and the wound electrode group is accommodated therein, the current collector located on the bottom side can be connected to the bottom on the structure. Can not. Therefore, the positive electrode current collector and the negative electrode current collector have to be arranged on the opening side, and the thickness of each of them is restricted.

  The present invention has been made in view of the above problems, and an object thereof is to provide a power storage device having high output and excellent vibration resistance, and a method for manufacturing the same.

Means [1] to [7] for solving the above problems are listed below.
[1] A rectangular metal can having an opening at one end of the cylindrical portion and a bottom at the other end of the cylindrical portion, a first electrode having a structure in which the first electrode is formed on the first current collector, A second electrode having a structure in which a second electrode having a different electrical property from the first electrode is formed on a second current collector; and a separator interposed between the first electrode and the second electrode. In the electric storage device in which a laminated electrode group is configured by laminating the first electrode, the second electrode, and the separator, and the laminated electrode group is housed in the rectangular metal can together with an electrolyte, A conductive metal connecting plate having an equal area is welded to the inner surface of the bottom portion, and a bulging portion is provided on a surface of the cylindrical portion that is not positioned in the thickness direction of the stacked electrode group. The inner space is made of an insulating rigid body and holds the connection plate and holds the laminated electrode group. A holding member is disposed, the first pole is connected to the connection plate, and the second is attached to the conductive metal lid fixed to the opening of the square metal can via an insulating gasket. An electricity storage device characterized in that poles are connected.

  Therefore, according to the invention described in the means 1, the first current collector of the first electrode constituting the stacked electrode group is connected to the connection plate, and the second current collector of the second electrode is connected to the lid made of conductive metal. By adopting a connection structure, the thickness of each current collector, which is a conductor for external lead-out, is less likely to be restricted, and a structure suitable for high output use can be obtained. Further, as a result of adopting a structure in which the laminated electrode group is accommodated in a rigid rectangular metal can, it can be securely fixed to the device, and a structure suitable for vibration-resistant applications can be obtained. Moreover, as a result of disposing a holding member made of an insulating rigid body in the internal space of the bulging portion provided on a predetermined surface of the square metal can, holding the connection plate and holding the laminated electrode group by this holding member, these members Rattling and misalignment are prevented. This also contributes to the improvement of vibration resistance.

  [2] The electricity storage device according to the above means 1, wherein the shape of the bulging portion when viewed from the opening side of the cylindrical portion is a semicircular shape.

  Therefore, according to the invention described in the means 2, for example, in the case where caulking is performed over the entire outer periphery of the cylindrical portion of the square metal can, the outer peripheral surface of the cylindrical portion is free of corners, so that processing is performed. It becomes easy.

  [3] The holding member has a structure in which base ends of a pair of columnar portions are connected to both ends of a flat plate portion, and the shape of the columnar portions when viewed from the opening side of the cylindrical portion is half. The electricity storage device according to the above means 2, which has a circular shape.

  Therefore, according to the invention described in the means 3, the connection plate is pressed and the laminated electrode group is held by the semicircular columnar portion arranged in the internal space of the bulging portion, so that these members are not loose. Misalignment is prevented. Moreover, even if it is a case where a columnar part should be arrange | positioned to each of the bulging part provided in one pair, since it is sufficient to use one holding member, the increase in a number of parts can be avoided.

  [4] The first electrode is a positive electrode having a structure in which a positive electrode made of a carbon material as the first electrode is formed on a positive electrode current collector that is the first current collector, and the second electrode Is a negative electrode having a structure in which a negative electrode made of a material capable of occluding and releasing lithium is formed on the negative electrode current collector that is the second current collector, and the electrolyte is lithium. A lithium metal support made of a conductive metal for supporting lithium metal for pre-doping is disposed at a position of the holding member facing the laminated electrode group in the holding member, and the lithium metal support is the negative electrode The electrical storage device according to any one of the above means 1 to 3, wherein the electrical storage device is electrically connected to a power feeding terminal electrically insulated from the positive electrode and the negative electrode.

  Therefore, according to the invention described in the means 4, the lithium metal is supported on the lithium metal support made of conductive metal, so that the handleability of the lithium metal is improved and the lithium metal is added to the negative electrode. Fast and uniform doping is possible. Further, by arranging the pre-doping lithium metal supported by the lithium metal support at the location facing the laminated electrode group in the holding member, the lithium metal can easily move relative to the negative electrode constituting the laminated electrode group. Thus, the doping can be performed efficiently. Furthermore, when the power supply terminal is provided, power can be supplied to the lithium metal support through the power supply terminal, so that doping can be performed more efficiently.

  [5] The method for manufacturing an electricity storage device according to any one of the above means 1 to 4, wherein the first electrode of the stacked electrode group is welded to the connection plate, and the second electrode is connected to the lid. An electrode welding process for welding to the metal, a housing process for housing the laminated electrode group that has undergone the electrode welding process in the square metal can, and an interior of the bulging portion in the square metal can after the housing process A connection plate welding step of welding the connection plate to the inner surface of the bottom portion by welding from the outside of the rectangular metal can while pressing the connection plate with the holding member disposed in the space. A method for manufacturing an electricity storage device.

  Therefore, according to the invention described in the means 5, by performing the electrode welding process prior to the housing process, the first electrode of the laminated electrode group is reliably and easily connected to the connection plate, and the second electrode is securely connected to the lid. And can be connected easily. In the subsequent connecting plate welding process, it is possible to perform welding from the outside of the rectangular metal can by pressing the connecting plate with a holding member arranged in the internal space of the bulging portion. Even if it exists, it can connect reliably and easily to the inner surface of a bottom part. Therefore, the first pole located on the bottom side and the bottom of the square metal can can be electrically connected.

  [6] The method for manufacturing an electricity storage device according to the above means 4, wherein an electrode welding step of welding the positive electrode of the laminated electrode group to the connection plate and welding the negative electrode to the lid, and the electrode welding The connecting plate is configured to accommodate the laminated electrode group that has undergone a process in the rectangular metal can, and the holding member disposed in the internal space of the bulging portion in the rectangular metal can after the accommodating process. A connection plate welding process for welding the connection plate to the inner surface of the bottom by performing welding from the outside of the rectangular metal can while pressing the metal plate, at least before the connection plate welding process. A conductive metal lithium metal support in a state of supporting a pre-doping lithium metal at a position facing the laminated electrode group in the holding member, and electrically connecting the lithium metal support to the negative electrode. A process for arranging a lithium metal to be connected, and an electrolyte injection process for injecting the electrolyte into the square metal can at a stage after the connection plate welding process is performed. Method.

  Therefore, according to the invention described in the means 6, by performing the electrode welding process prior to the housing process, the positive electrode of the laminated electrode group is reliably and easily connected to the connection plate, and the negative electrode is reliably and easily connected to the lid. Can be connected. In the subsequent connecting plate welding process, it is possible to perform welding from the outside of the rectangular metal can by pressing the connecting plate with a holding member arranged in the internal space of the bulging portion. Even if it exists, it can connect reliably and easily to the inner surface of a bottom part. Therefore, the positive electrode located on the bottom side and the bottom of the square metal can can be electrically connected. Then, by performing the lithium metal placement step and the electrolyte injection step, lithium metal pre-doping with respect to the negative electrode can be performed reliably, and an electricity storage device can be obtained.

  [7] The method of manufacturing an electricity storage device according to the above means 4, wherein an electrode welding step of welding the positive electrode of the laminated electrode group to the connection plate and welding the negative electrode to the lid, and the electrode welding The connecting plate is configured to accommodate the laminated electrode group that has undergone a process in the rectangular metal can, and the holding member disposed in the internal space of the bulging portion in the rectangular metal can after the accommodating process. A connection plate welding process for welding the connection plate to the inner surface of the bottom by performing welding from the outside of the rectangular metal can while pressing the metal plate, at least before the connection plate welding process. A lithium metal support made of a conductive metal in a state of supporting a pre-doping lithium metal at a position facing the laminated electrode group in the holding member, and the lithium metal support is formed with the positive electrode and the lithium metal support. An electrolyte injection step of performing a lithium metal arrangement step of electrically connecting to a power feeding terminal insulated from a pole, and injecting the electrolyte into the rectangular metal can at a stage after the connection plate welding step A power feeding step in which a positive voltage is applied to the power feeding terminal and a negative voltage is applied to the negative electrode for power feeding, and a sealing step in which the power feeding terminal is sealed with an insulator so that the power feeding terminal is not exposed. A method for manufacturing an electricity storage device, which is performed in this order.

  Therefore, according to the invention described in the means 7, by performing the electrode welding process prior to the housing process, the positive electrode of the laminated electrode group is reliably and easily connected to the connection plate, and the negative electrode is reliably and easily connected to the lid. Can be connected. In the subsequent connecting plate welding process, it is possible to perform welding from the outside of the rectangular metal can by pressing the connecting plate with a holding member arranged in the internal space of the bulging portion. Even if it exists, it can connect reliably and easily to the inner surface of a bottom part. Therefore, the positive electrode located on the bottom side and the bottom of the square metal can can be electrically connected. After that, by performing a lithium metal placement step, an electrolyte injection step, a power feeding step, and the like, lithium metal pre-doping to the negative electrode can be performed more efficiently and reliably.

  As described in detail above, according to the inventions described in claims 1 to 4, it is possible to provide a power storage device that has high output and excellent vibration resistance. Moreover, according to invention of Claim 5-7, the manufacturing method of the electrical storage device which can obtain said outstanding electrical storage device reliably and easily can be provided.

The perspective view when the lithium ion capacitor of 1st Embodiment is seen from the bottom part side. The perspective view when the lithium ion capacitor is viewed from the lid side. (A) is sectional drawing of the lithium ion capacitor, (b) is the sectional view on the AA line of (a), (c) is a top view of a connection board. (A) is the front view of the holding member in 1st Embodiment, (b) is the top view, (c) is the front view of the holding member in the modification 1, (d) is the top view, (e) is a deformation | transformation. The front view of the holding member in Example 2, (f) is the top view. The figure for demonstrating the manufacturing procedure of the lithium ion capacitor. The figure for demonstrating the manufacturing procedure of the lithium ion capacitor. The figure for demonstrating the manufacturing procedure of the lithium ion capacitor. (A) is sectional drawing of the lithium ion capacitor of 2nd Embodiment, (b) is the BB sectional drawing of (a). Sectional drawing of the lithium ion capacitor of 3rd Embodiment. Sectional drawing of the lithium ion capacitor of another embodiment. Sectional drawing of the lithium ion capacitor of another embodiment.

[First Embodiment]
Hereinafter, an embodiment in which the electricity storage device of the present invention is embodied in a lithium ion capacitor will be described in detail with reference to FIGS. 1 and 2 are perspective views of the lithium ion capacitor 11 of the present embodiment. 3A is a cross-sectional view of the lithium ion capacitor 11, FIG. 3B is a cross-sectional view taken along line AA, and FIG. 3C is a plan view of the connection plate. 4A is a front view of the holding member in the embodiment, FIG. 4B is a plan view thereof, FIG. 4C is a front view of the holding member in the first modification, and FIG. 4D is a plan view thereof. FIG. 4E is a front view of the holding member in the second modification, and FIG. 4F is a plan view thereof. 5-7 is a figure for demonstrating the manufacturing procedure of the lithium ion capacitor 11. FIG.

  As shown in FIG. 3, the lithium ion capacitor 11 of this embodiment includes a stacked electrode group 51 in which a plurality of positive electrodes 31 (first electrodes), negative electrodes 41 (second electrodes), and separators 46 are stacked. ing. The number of positive electrodes 31 and negative electrodes 41 is not limited to that shown in the figure, and may be more or less than this.

  The positive electrode 31 has a structure in which a positive electrode (first electrode; not shown) made of a carbon material is formed on a positive electrode current collector 33 (first current collector).

  Examples of carbon materials that form the positive electrode include various natural graphites that have been appropriately pulverized, synthetic graphite, graphite materials such as expanded graphite, mesocarbon microbeads that have been carbonized, and mesophase pitch-based carbon fibers. And synthetic graphite materials obtained by subjecting carbon materials such as vapor-grown carbon fiber, pyrolytic carbon, petroleum coke, pitch coke and needle coke to graphitization, or a mixture thereof. These carbon materials are kneaded and molded together with a conductive agent and a binder as necessary.

  Examples of the conductive agent include various graphite materials and carbon black. Among them, it is preferable to use conductive carbon blacks. Specific examples include channel black, oil furnace black, lamp black, thermal black, acetylene black, ketjen black, etc., but it is possible to select acetylene black in terms of excellent liquid retention and low electrical resistance. Particularly preferred.

  The binder is not particularly limited as long as it is insoluble in the organic electrolyte. For example, a fluorine-based resin such as polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyvinyl fluoride (PVF), or carboxymethylcellulose. Organic polymer compounds such as alkali metal salts or ammonium salts, polyimide resins, polyamide resins, polyacrylic acid and sodium polyacrylate are suitable.

  The positive electrode current collector 33 is a member for collecting current while supporting the positive electrode. For example, a conductive metal foil such as aluminum or stainless steel or a conductive metal plate is preferably used. Stainless steel is a suitable material in that it is not alloyed with lithium and is less susceptible to electrochemical oxidation.

  The positive electrode current collector 33 is formed in a rectangular flat plate size that can be accommodated in the rectangular metal can 21 as a container, and a part of the positive electrode current collector 33 protrudes from the lower side of the separator 46.

  The negative electrode 41 has a structure in which a negative electrode (second electrode; not shown) made of a material capable of inserting and extracting lithium ions is formed on a negative electrode current collector 43 (second current collector). Here, the metal supplying lithium ions not only refers to a single lithium metal, but widely refers to all substances that contain lithium and can supply lithium ions, such as lithium-aluminum alloys. Yes.

The negative electrode is formed of a material capable of inserting and extracting lithium ions. Specific examples thereof include lithium metal, lithium-aluminum alloy, graphite material, graphitizable carbon material, non-graphitizable carbon material, niobium pentoxide (Nb ₂ O ₅ ), lithium titanate (Li ₄ Ti ₅ O). ₁₂ ), silicon monoxide (SiO), tin monoxide (SnO), a composite oxide of tin and lithium (Li ₂ SnO ₃ ), a composite oxide of lithium, phosphorus and boron (for example, LiP _0.4 B _{0. 6} O _2.9 ). Among these, carbon materials such as graphite materials, graphitizable carbon materials, and non-graphitizable carbon materials are suitable as negative electrode materials because they have properties such as high reversibility.

  Examples of carbon materials that form the negative electrode include various natural graphites that have been appropriately pulverized, graphite materials such as synthetic graphite, expanded graphite, mesocarbon microbeads that have been carbonized, and mesophase pitch carbon fibers And carbon materials such as vapor grown carbon fiber, pyrolytic carbon, petroleum coke, pitch coke and needle coke, or a mixture thereof. The carbon materials for negative electrodes listed here are kneaded and molded together with a conductive agent and a binder as necessary. As the conductive agent and binder, the materials exemplified in the description of the positive electrode can be used as they are.

  The separator 46 interposed between the negative electrode 41 and the positive electrode 31 is durable to an organic electrolyte, an electrode active material, and the like, and is made of a non-conductive porous body having continuous air holes. Usually, a cloth, a nonwoven fabric or a porous body made of glass fiber, polyethylene, polypropylene or the like is used. The thickness of the separator 46 is preferably thin in order to reduce the internal resistance of the capacitor, but can be set as appropriate in consideration of the amount of retained organic electrolyte, flowability, strength, and the like.

The separator 46 is usually impregnated with a liquid organic electrolyte, but a gel or solid organic electrolyte may be used to prevent leakage. Here, the organic electrolyte is obtained by dissolving a compound capable of generating a doped lithium ion in an aprotic organic solvent. Examples of the compound include organic lithium salts. Preferred examples thereof include lithium hexafluorophosphate represented as LiPF ₆ and lithium bis (trifluoromethanesulfone) represented as LiN (CF ₃ SO ₂ ) _2. Examples include imide and lithium bis (pentafluoroethanesulfone) imide represented by LiN (C ₂ F ₅ SO ₂ ) ₂ . Moreover, as a suitable example of the said aprotic organic solvent, propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), (gamma) -butyrolactone (GBL), vinylene carbonate (VC), acetonitrile (AN), for example ), Dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC) and derivatives thereof, or a mixed solvent thereof.

  The negative electrode current collector 43 is a member for collecting current while supporting the negative electrode. For example, a conductive metal foil such as copper, nickel, stainless steel, or a conductive metal plate is preferably used.

  The negative electrode current collector 43 is formed in a rectangular flat plate size that can be accommodated in the rectangular metal can 21, and a part thereof protrudes from the upper side of the separator 46.

  As shown in FIGS. 1 to 3, the lithium ion capacitor 11 of the present embodiment includes a rectangular metal can 21 that is a container for housing the laminated electrode group 51. The rectangular metal can 21 has an opening at one end of the cylindrical portion 22 and a bottom 23 at the other end of the cylindrical portion 22. A lid 54 is fixed to the opening by caulking through an insulating gasket 53 made of synthetic resin or the like. On the outer peripheral surface of the cylindrical portion 22 of the square metal can 21, a groove portion 26 generated by caulking is formed. The lid 54 is a member made of conductive metal having a plate-like main body 54a and a tab portion 54b protruding from the plate-like main body 54a. In particular, the tab portion 54b functions as a part of a conductor for leading out the negative electrode 41. doing. And the negative electrode collector 43 is being fixed to the lower surface side of the plate-shaped main body 54a of such a cover body 54 by welding (refer Fig.3 (a)).

  Although the bottom part 23 may be joined with respect to the cylinder part 22, it may be integrally formed using the same electroconductive metal material. On the inner surface side of the bottom portion 23, a conductive metal connecting plate 52 having a shape and an area substantially equal to the bottom portion 23 is installed and fixed to the inner surface of the bottom portion 23 by welding (in FIG. 1). (See weld 27 shown).

  Here, the cylindrical portion 22 has a pair of large parallel surfaces, and the laminated electrode group 51 is accommodated in the rectangular metal can 21 so as to be parallel to the parallel surfaces. . A pair of bulging portions 24 are provided on the surface of the cylindrical portion 22 that is not positioned in the thickness direction of the multilayer electrode group 51. Although the shape of the bulging portion 24 is not particularly limited, in the present embodiment, the bulging portion 24 having a semicircular shape when viewed from the opening side of the cylindrical portion 22 is formed. An internal space 25 exists inside the bulging portions 24, and a holding member 61 is disposed in the internal space 25. The holding member 61 of this embodiment shown in FIGS. 4 (a) and 4 (b) is a member made of an insulating rigid body, and holds the connection plate 52 in the accommodated state in the rectangular metal can 21 and is a laminated electrode group. It plays the role of holding 51. Any material (synthetic resin, ceramic, etc.) can be used as long as it is an insulating rigid body, but it is preferable to use a synthetic resin such as epoxy from the viewpoint of cost and workability. Incidentally, the “rigid body” referred to here refers to a material having a strength equal to or higher than that of a synthetic resin material for gaskets, for example. The holding member 61 has a pair of columnar portions 62 having a semicircular shape when viewed from the opening side of the cylindrical portion 22. The pair of columnar portions 62 are spaced apart with the flat surfaces 62 a facing each other, and the respective base end portions are connected to both ends of the flat plate portion 63. The flat plate portion 63 is formed with a rectangular cutout portion 64 having a width corresponding to the width of the positive electrode current collector 33, and the positive electrode current collector 33 is arranged in the cutout portion 64. Yes. The positive electrode current collector 33 is fixed to the upper surface of the connection plate 52 by welding (see FIG. 3A).

  4 (c) and 4 (d) show a holding member 61A according to Modification 1. In this holding member 61A, a rectangular through groove 65 is formed instead of the notch 64. FIG. 4E and 4F show a holding member 61B according to the second modification, in which the flat plate portion 63 that is a connecting portion is omitted.

  Next, an example of a method for manufacturing the lithium ion capacitor 11 of the present embodiment will be described with reference to FIGS.

  First, the laminated electrode group 51 formed by laminating the positive electrode 31, the negative electrode 41, and the separator 46 is prepared and prepared (see FIG. 5). In the present embodiment, the positive electrode current collector 33 of the positive electrode 31 and the negative electrode current collector 43 of the negative electrode 41 are protruded in opposite directions, so that each can be formed with a sufficient thickness. Of course, this contributes to higher output.

  The positive electrode 31 is manufactured according to the following procedure. First, a mixed slurry containing a carbon material, a conductive agent and a binder is prepared, and this is applied to an aluminum foil having a thickness of 20 μm which is the positive electrode current collector 33 to form a positive electrode. After the positive electrode is dried and pressed, the positive electrode 31 is formed by cutting into a predetermined size with a mold. The negative electrode 41 is produced by the following procedure. First, a mixed slurry containing a carbon material and a binder is prepared, and this is applied to a copper foil having a thickness of 12 μm which is the negative electrode current collector 43 to form a negative electrode. Next, after drying and pressing the negative electrode, the negative electrode 41 is formed by cutting into a predetermined size with a mold. Then, a separator 46 is interposed between the positive electrode 31 and the negative electrode 41 to form a laminated electrode group 51.

  Next, each positive electrode current collector 33 of the positive electrode 31 in the laminated electrode group 51 is fixed by welding to the connection plate 52, and each negative electrode current collector 43 of the negative electrode 41 is fixed by welding to the lid 54. (Electrode welding process; see FIG. 6). The welding method is not particularly limited, and conventionally known methods such as arc welding, electron beam welding, laser beam welding, resistance welding, and ultrasonic welding can be arbitrarily selected. Even if any welding method is adopted, the positive electrode current collector 33 and the negative electrode current collector 43 can be reliably and easily connected by performing the electrode welding process prior to the housing process. . Either the positive electrode current collector 33 or the negative electrode current collector 43 may be welded first.

  Next, the holding member 61 is disposed with respect to the laminated electrode group 51. More specifically, the flat plate portion is disposed between the lower surface of the multilayer electrode group 51 and the upper surface of the connection plate 52 so that the positive electrode current collector 33 is positioned in the notch portion 64 formed in the flat plate portion 63 of the holding member 61. 63 is inserted. In this case, the pair of columnar portions 62 in the holding member 61 are disposed on the side surfaces of the stacked electrode group 51, and the flat surface 62 a of the columnar portions 62 faces the side surfaces of the stacked electrode group 51. Further, a gasket 53 is disposed on the laminated electrode group 51 so as to surround the outer peripheral portion of the plate-shaped main body 54 a of the lid 54. According to FIG. 6, the lower surface of the gasket 53 is supported in contact with the front end surfaces of the pair of columnar portions 62. Accordingly, the holding member 61 of this embodiment also plays a role as a pedestal that supports the gasket 53 as a result. In addition, you may arrange | position the gasket 53 and the holding member 61 before performing an electrode welding process.

  Next, a rectangular metal can 21 having a predetermined shape is prepared, and the laminated electrode group 51 in the state of FIG. 6 that has undergone the electrode welding process is placed in the rectangular metal can 21 with the connection plate 52 side facing down. (Receiving process). After the housing, the connection plate 52 is disposed in contact with the inner surface of the bottom 23 of the square metal can 21. In addition, a pair of columnar portions 62 of the holding member 61 are disposed in the internal space 25 of the pair of bulging portions 24 in the square metal can 21. Thereafter, a downward force is applied to the holding member 61 to press the connection plate 52 against the inner surface side of the bottom portion 23, and the resistance welding electrode 81 is brought into contact with the outer surface side of the bottom portion 23, so that the outer side of the rectangular metal can 21. Welding is performed (connection plate welding process; see FIG. 7). As a result, the connecting plate 52 is welded and fixed to the inner surface of the bottom portion 23, whereby the positive electrode 31 of the laminated electrode group 51 is electrically connected to the square metal can 21 through the connecting plate 52. In this case, arc welding, electron beam welding, laser beam welding, ultrasonic welding, or the like may be performed instead of resistance welding. According to the present embodiment, since the connection plate 52 can be pressed by the holding member 61 even in the stacked electrode group accommodation state, welding can be performed from the outside of the rectangular metal can 21. The connection can be made reliably and easily.

  Next, by crimping the vicinity of the opening of the cylindrical portion 22 over the entire outer peripheral surface, the lid body 54 is fixed to the opening through the gasket 53, and the rectangular metal can 21 is sealed. In this embodiment, since the bulging part 24 is semicircular and there is no corner | angular part in the outer peripheral surface of the cylinder part 22, a crimping process can be performed comparatively easily. Further, the electrolyte is injected while evacuating through a hole (not shown), and the rectangular metal can 21 is surely filled with the electrolyte, thereby completing the lithium ion capacitor 11 shown in FIG.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) In the lithium ion capacitor 11 of the present embodiment, the positive electrode current collector 33 of the positive electrode 31 constituting the multilayer electrode group 51 is connected to the connection plate 52, and the negative electrode current collector 43 of the negative electrode 41 is made of a conductive metal lid. A structure connected to the body 54 is adopted. As a result, the thicknesses of the positive electrode current collector 33 and the negative electrode current collector 43 which are conductors for external lead are less likely to be restricted, and a structure suitable for high output applications can be obtained. Further, as a result of adopting a structure in which the laminated electrode group 51 is accommodated in the rigid rectangular metal can 21, it can be securely fixed to the device, and a structure suitable for vibration-resistant applications can be obtained. In addition, a holding member 61 made of an insulating rigid body is disposed in the internal space 25 of the bulging portion 24 provided on a predetermined surface of the square metal can 21, and the connection plate 52 is pressed by the holding member 61 and the laminated electrode group 51. To keep. Therefore, rattling and displacement of these members can be prevented. This also contributes to the improvement of vibration resistance.

  From the above, according to the present embodiment, it is possible to provide the lithium ion capacitor 11 having high output and excellent vibration resistance.

  (2) The holding member 61 of the present embodiment has a structure in which the base end portions of the pair of columnar portions 62 are connected to both ends of the flat plate portion 63, when viewed from the opening side of the cylindrical portion 22. The columnar part 62 has a semicircular shape. Accordingly, the connection plate 52 is pressed by the semicircular columnar portion 62 and the laminated electrode group 51 is held, so that the backlash and displacement of these members are prevented. Moreover, even if it is a case where the columnar part 62 is desired to be arranged in each of the pair of bulging parts 24, since it is sufficient to use one holding member 61, an increase in the number of parts can be avoided.

(3) According to the manufacturing method of this embodiment in which the electrode welding process, the housing process, and the connection plate welding process are sequentially performed, the above-described excellent lithium ion capacitor 11 having high output and excellent vibration resistance is surely and easily obtained. Can get to.
[Second Embodiment]

  Hereinafter, a second embodiment in which the electricity storage device of the present invention is embodied in a lithium pre-doped lithium ion capacitor will be described in detail with reference to FIG. FIG. 8A is a sectional view of the lithium ion capacitor 11A, and FIG. 8B is a sectional view taken along the line BB.

  The lithium pre-doped lithium ion capacitor 11A of the present embodiment is substantially the same as the lithium ion capacitor 11 of the first embodiment described above, but differs in the following points. That is, the lithium ion capacitor 11 has a structure in which a lithium metal 71 for pre-doping (for example, a lithium metal foil) is accommodated in a square metal can 21 in advance. The lithium metal 71 for pre-doping is supported on a lithium metal support 72 made of a conductive metal such as a copper plate. The lithium metal support 72 that supports the lithium metal 71 is disposed on the holding member 61 at a location facing the stacked electrode group 51, specifically, on the flat surface 62 a of the pair of columnar portions 62. The lithium metal support 72 is electrically connected to, for example, the negative electrode current collector 43 at least before pre-doping.

  The lithium ion capacitor 11A having the above structure is manufactured in accordance with the manufacturing procedure of the first embodiment described above. In that case, what is necessary is just to implement the process after an accommodation process using the holding member 61 provided with the lithium metal support body 72 which supported the lithium metal 71. FIG. Then, after performing the electrolyte injection step in the final stage of manufacture, the pre-doping is advanced by holding for a predetermined time. As a result, lithium ions can be sufficiently distributed to the negative electrode 41, and the pre-doping can proceed promptly and reliably. As a result, the lithium ion capacitor 11A shown in FIG. 8 is completed. When pre-doping is completed, the lithium metal 71 usually dissolves and disappears.

Even in the second embodiment described above, the lithium ion capacitor 11A having high output and excellent vibration resistance can be provided, and the above-described excellent lithium ion capacitor 11A can be obtained reliably and easily. be able to.
[Third embodiment]

  Hereinafter, a third embodiment in which the electricity storage device of the present invention is embodied in a lithium pre-doped lithium ion capacitor will be described in detail with reference to FIG.

  The lithium ion capacitor 11B includes a lithium metal support 72 that supports a lithium metal 71 as in the second embodiment. However, the lithium metal support 72 of this embodiment is not connected to the negative electrode 41. Further, the upper end portion of the lithium metal support 72 is extended to serve as a power feeding terminal 73, and reaches the terminal through holes provided at two places in the plate-like main body 54 a of the lid 54. The gap between the power feeding terminal 73 and the terminal through hole is filled with a resin insulator 74, so that the lithium metal support 72 is also insulated from the lid 54.

  The lithium ion capacitor 11B having the above-described structure can be manufactured according to the manufacturing procedure of the second embodiment described above. However, after the electrolyte injection step, the lithium ion capacitor 11B is insulated from the positive electrode 31 and the negative electrode 41. Power is supplied by applying a positive voltage to the power supply terminal 73 and applying a negative voltage to the negative electrode 41 (power supply process). As a result, the lithium metal 71 can be pre-doped into the negative electrode 41 more efficiently and reliably. After completion of pre-doping, a sealing process is further performed with an insulator 74 so that the power supply terminal 73 is not exposed to complete the lithium ion capacitor 11B shown in FIG.

  Even in the third embodiment described above, the lithium ion capacitor 11B having high output and excellent vibration resistance can be provided, and the above-described excellent lithium ion capacitor 11B can be obtained reliably and easily. be able to.

  In addition, you may change embodiment of this invention as follows.

  In the second and third embodiments, the lithium metal 71 is supported by the lithium metal support 72, and the lithium metal support 72 is attached to the holding member 61. However, this may be attached to another position. . For example, in the lithium ion capacitor 11 </ b> C of another embodiment shown in FIG. 10, the lithium metal 71 is disposed in the space between the multilayer electrode group 51 and the connection plate 52 or in the space between the multilayer electrode group 51 and the lid 54. Is disposed on the lithium metal support 72. Such a structure may be connected to the negative electrode current collector 43 by some means, or may be directly joined on the negative electrode current collector 43. A lithium ion capacitor 11 </ b> D of another embodiment shown in FIG. 11 has the same structure, but a power supply terminal 73 is provided inside the holding member 61, and a lithium metal is connected to the power supply terminal 73. A structure in which 71 is supported on a lithium metal support 72 is connected. Therefore, if a power feeding process is performed using the power feeding terminal 73, the lithium metal 71 can be pre-doped into the negative electrode 41 more efficiently and reliably.

  In each of the above embodiments, the holding member is configured using a material made of a solid body (non-porous body) that is somewhat rigid, but the holding member may be configured using a material made of a porous body. In this case, the liquid retention of the electrolyte can be improved.

  In each of the above embodiments, the semicircular bulging portion 24 is provided, but a bulging portion having a shape other than the semicircular shape (for example, a rectangular shape or a triangular shape) may be provided. In the above embodiment, a pair of the bulging portions 24 are provided, but only one of them may be provided.

  In the second embodiment, in order to prevent a short circuit with the positive electrode 31 and the negative electrode 41, a gap is provided between the flat surface 62a of the columnar portion 62 and the stacked electrode group 51 in the holding member 61. When the lithium metal 71 is not disposed in 62a, the gap may be eliminated.

  In the second and third embodiments, the present invention is embodied in a lithium pre-doped lithium ion capacitor. However, the present invention may be embodied in a type of alkali metal ion capacitor in which an alkali metal other than lithium is pre-doped. Alternatively, the present invention can be embodied in an electricity storage device such as a non-aqueous secondary battery or an electric double layer capacitor.

  In each of the above embodiments, the lid 54 is fixed to the opening of the square metal can 21 by caulking, but may be fixed by a method other than caulking.

  In each of the above embodiments, the positive electrode 31 is the first pole and the negative electrode 41 is the second pole, but this relationship may be reversed. That is, a configuration in which the negative electrode 41 is welded to the connection plate 52 as the first pole while the positive electrode 31 is welded to the lid body 54 as the second pole may be employed.

DESCRIPTION OF SYMBOLS 11, 11A, 11B, 11C, 11D ... Lithium ion capacitor as an electrical storage device 21 ... Square metal can 22 ... Cylindrical part 23 ... Bottom part 24 ... Swelling part 25 ... Internal space of swelling part 33 ... 1st electrical power collector As a first electrode 41 as a first electrode 41 as a second electrode 43 as a second current collector 46 as a second current collector 46 a separator 51 a laminated electrode group 52 as a connection plate 53 54 ... Lid 61, 61A, 61B ... Holding member 62 ... Columnar portion 63 ... Flat plate portion 71 ... Lithium metal 72 ... Lithium metal support 73 ... Feeding terminal 74 ... Insulator

Claims (7)

A square metal can having an opening at one end of a cylindrical portion and a bottom at the other end of the cylindrical portion; a first electrode having a structure in which a first electrode is formed on a first current collector; and the first A second electrode having a structure in which a second electrode having a different electrical property from the electrode is formed on the second current collector, and a separator interposed between the first electrode and the second electrode, In the electricity storage device in which a laminated electrode group is configured by laminating the first electrode, the second electrode, and the separator, and the laminated electrode group is housed in the rectangular metal can together with an electrolyte.
A conductive metal connecting plate having an area equal to the bottom is welded to the inner surface of the bottom,
A bulging portion is provided on the surface of the cylindrical portion that is not positioned in the thickness direction of the stacked electrode group,
In the internal space of the bulging portion, a holding member that is made of an insulating rigid body and holds the laminated electrode group and holds the connection plate is disposed,
The first pole is connected to the connection plate, and the second pole is connected to a conductive metal lid fixed to the opening of the square metal can via an insulating gasket. A power storage device characterized.   The power storage device according to claim 1, wherein a shape of the bulging portion when viewed from the opening side of the cylindrical portion is a semicircular shape.   The holding member has a structure in which the base end portions of a pair of columnar portions are connected to both ends of a flat plate portion, and the shape of the columnar portions when viewed from the opening side of the cylindrical portion is a semicircular shape. The power storage device according to claim 2, wherein the power storage device is provided. The first electrode is a positive electrode having a structure in which a positive electrode made of a carbon material as the first electrode is formed on a positive electrode current collector that is the first current collector,
The second electrode is a negative electrode having a structure in which a negative electrode made of a material capable of occluding and releasing lithium is formed on the negative electrode current collector as the second current collector,
The electrolyte contains a lithium salt;
A conductive metal lithium metal support for supporting the pre-doping lithium metal is disposed at a position facing the laminated electrode group in the holding member, and the lithium metal support is electrically connected to the negative electrode. 4. The power storage device according to claim 1, wherein the power storage device is electrically connected to a power feeding terminal insulated from the positive electrode and the negative electrode. 5. It is a manufacturing method of the electrical storage device according to any one of claims 1 to 4,
An electrode welding step of welding the first electrode of the stacked electrode group to the connection plate and welding the second electrode to the lid;
An accommodating step of accommodating the laminated electrode group that has undergone the electrode welding step in the rectangular metal can;
After the housing step, the connection is performed by welding from the outside of the square metal can while pressing the connection plate with the holding member arranged in the internal space of the bulging portion of the square metal can. And a connecting plate welding step of welding a plate to the inner surface of the bottom portion. It is a manufacturing method of the electrical storage device according to claim 4,
An electrode welding step of welding the positive electrode of the laminated electrode group to the connecting plate and welding the negative electrode to the lid;
An accommodating step of accommodating the laminated electrode group that has undergone the electrode welding step in the rectangular metal can;
After the housing step, the connection is performed by welding from the outside of the square metal can while pressing the connection plate with the holding member arranged in the internal space of the bulging portion of the square metal can. A connecting plate welding step of welding a plate to the inner surface of the bottom,
At least prior to the connection plate welding step, a conductive metal lithium metal support in a state of supporting the pre-doping lithium metal is disposed at a location facing the laminated electrode group in the holding member, and Performing a lithium metal placement step of electrically connecting a lithium metal support to the negative electrode;
A method for manufacturing an electricity storage device, comprising performing an electrolyte injection step of injecting the electrolyte into the rectangular metal can at a stage after the connection plate welding step. It is a manufacturing method of the electrical storage device according to claim 4,
An electrode welding step of welding the positive electrode of the laminated electrode group to the connecting plate and welding the negative electrode to the lid;
An accommodating step of accommodating the laminated electrode group that has undergone the electrode welding step in the rectangular metal can;
After the housing step, the connection is performed by welding from the outside of the square metal can while pressing the connection plate with the holding member arranged in the internal space of the bulging portion of the square metal can. A connecting plate welding step of welding a plate to the inner surface of the bottom,
At least prior to the connection plate welding step, a conductive metal lithium metal support in a state of supporting the pre-doping lithium metal is disposed at a location facing the laminated electrode group in the holding member, and Performing a lithium metal placement step of electrically connecting a lithium metal support to a power feeding terminal insulated from the positive electrode and the negative electrode;
An electrolyte injection step of injecting the electrolyte into the rectangular metal can at a later stage of the connection plate welding step, applying a positive voltage to the power supply terminal and applying a negative voltage to the negative electrode A method for manufacturing an electricity storage device, wherein a power feeding step for feeding power and a sealing step for sealing with an insulator so that the power feeding terminal is not exposed are performed in this order.

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