Storage element and method for manufacturing the same

Abstract

The power storage element (C) has an outer current collector (1) having outer opposite walls (1a) opposite each other at intervals in an opposite direction (X) and an inner current collector (3) having inner opposite walls (3a), and an electrode body (13) is disposed in a space formed between the opposite walls, wherein the electrode body (13) is formed of a sheet-like electrode laminate (43) including a positive electrode body (17), a negative electrode body (19), and a separator (21) interposed between the positive electrode body and the negative electrode body, and is configured to have a plurality of unit electrode layers (13a) stacked in a stacking direction (Z) orthogonal to the opposite direction, and the unit electrode layers adjacent in the stacking direction are connected by being bent at end portions in an extending direction (Y), and the positive electrode body (17) and the negative electrode body (19) are electrically connected to the current collectors by being in contact with one and the other current collectors, respectively.

Description

TECHNICAL FIELD

[0001] The present application relates to a configuration of an electricity storage element and a manufacturing method thereof. BACKGROUND

[0002] As one of the configurations of an electricity storage element, for example, a battery configuration, a configuration in which an electrode body of a ring shape is disposed between each current collector of a positive electrode and a negative electrode of a double cylindrical shape is proposed (see Patent Literature 1).

[0003] PRIOR ART DOCUMENT

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2018-206575 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In the battery disclosed in Patent Literature 1, the electrode body is configured by laminating a plurality of positive electrode bodies and negative electrode bodies and separators each of which is formed in a sheet shape of a ring shape. A process of cutting out these sheet-shaped bodies from a base sheet serving as a base and a process of laminating them are required. In addition, cut-out ring-shaped sheets need to be prepared according to the number of laminations. In addition, for example, in the case where the process of laminating the cut-out sheet-shaped bodies is performed by hand work, a large amount of labor and time is required. Therefore, it is difficult to increase the number of electrode bodies that can be manufactured per unit time.

[0008] To solve the above problem, an object of the present application is to increase the number of electrode bodies that can be manufactured per unit time.

[0009] MEANS FOR SOLVING THE PROBLEM

[0010] To achieve the object, the electricity storage element of the present application has:

[0011] a pair of outer current collectors which oppose each other at intervals along a predetermined opposing direction;

[0012] a pair of inner current collectors which are disposed on the inner side of the opposing direction of the pair of outer current collectors and oppose each other at intervals along the opposing direction; and

[0013] an electrode body which is disposed in a space formed between the pair of outer current collectors and the pair of inner current collectors; wherein

[0014] The electrode body is configured so that a plurality of sheet-like unit electrode layers including positive electrode bodies, negative electrode bodies, and separators sandwiched between the positive electrode bodies and the negative electrode bodies are stacked in a predetermined stacking direction orthogonal to the facing direction, and the unit electrode layers adjacent in the stacking direction are connected by bending end portions in an extension direction orthogonal to the facing direction and the stacking direction,

[0015] Each positive electrode body that configures each unit electrode layer is electrically connected to one of the current collectors by being in contact with the one of the current collectors, the one of the current collectors being either of the outer current collector and the inner current collector,

[0016] Each negative electrode body that configures each unit electrode layer is electrically connected to the other of the current collectors by being in contact with the other of the current collectors, the other of the current collectors being the other of the outer current collector and the inner current collector.

[0017] According to this structure, as the electrode body, a stacking structure of a plurality of unit electrode layers can be realized in a bent configuration in which the unit electrode layers are connected at end portions in the extension direction. Thus, it is not necessary to cut the sheet-like body according to the number of unit electrode layers, and the number of components can be reduced at the time of assembling the power storage element. In addition, the number of operations can be reduced by not performing the operation of cutting and the operation of stacking the cut sheet-like bodies. In this way, the number of electrode bodies that can be manufactured per unit time can be increased.

[0018] In the power storage element of one embodiment of the present application, the plurality of unit electrode layers can be stacked by being wound or folded in a manner in which both end portions of the sheet-like electrode stack in the extension direction are bent. According to this structure, three or more unit electrode layers arranged in the stacking direction can be formed with one sheet-like body, and the number of components and the number of operation man-hours can be reduced.

[0019] In the power storage element of one embodiment of the present application, at least one of the positive electrode body and the negative electrode body that configures each unit electrode layer can be in contact with both of a pair of facing walls arranged in the facing direction and electrically connected to the corresponding current collector. According to this structure, the pair of facing walls can function as the current collectors, the distance through which electrons move from the negative electrode to the positive electrode in the electrode body can be shortened, and the internal resistance in the power storage element can be reduced.

[0020] In the power storage element of one embodiment of the present application, the unit electrode layer of the electrode body can have a portion in which the dimensions in the opposing direction are formed to be the same length in a prescribed range in the extending direction. According to this structure, the end surface in the opposing direction can be formed in a straight line by the portion in which the dimensions in the opposing direction are formed to be the same length. Thus, the electrode body is easily brought into line contact with the opposing wall, and contact failure of the electrode body and the current collector can be inhibited. For example, by forming the portion in which the dimensions in the opposing direction of a plurality of unit electrode layers which are adjacent in the stacking direction are formed to be the same length, the end surface in the opposing direction of the current collector can be formed in a flat surface. Thus, the electrode body is easily brought into surface contact with the opposing wall, and contact failure of the electrode body and the current collector can be further inhibited.

[0021] In the power storage element of one embodiment of the present application, each unit electrode layer of the electrode body can have a rectangular shape in which edges in the extending direction and the opposing direction are respectively formed when viewed in the stacking direction. According to this structure, the density of unit cubic spaces can be increased as compared to the case where the shape viewed in the stacking direction is circular.

[0022] In the power storage element of one embodiment of the present application, the through hole can have a long hole shape which extends in an extending direction orthogonal to the opposing direction and the stacking direction. According to this structure, by providing the through hole as a long hole, the inner side contact surface is easily formed to be long as compared to the case where the through hole is circular, and the internal resistance in the power storage element can be reduced.

[0023] In the power storage element of one embodiment of the present application, the length of the extending direction of the through hole can be formed to be longer than the length of the extending direction of the inner side opposing wall. According to this structure, when the electrode body is bent, a margin for reliably contacting the inner side opposing wall can be ensured with respect to positional displacement generated in the through hole, and contact failure of the electrode body and the inner side opposing wall can be prevented.

[0024] In the power storage element of one embodiment of the present application, a concave-convex which prevents positional displacement of the electrode body which is in contact can be formed on at least either of the outer side opposing wall and the inner side opposing wall. According to this structure, contact failure of the electrode body and the opposing wall can be prevented, and reduction in current collecting efficiency can be prevented.

[0025] In the power storage element of one embodiment of the present application, at least either of the outer side current collector and the inner side current collector can have a reinforcing mechanism which prevents deformation in the opposing direction. With this structure, deformation of the current collector can be inhibited, contact failure of the positive electrode body, the negative electrode body, and the opposing wall can be prevented, and reduction in current collecting efficiency can be prevented.

[0026] The power storage element module of the present application is a power storage element module in which a plurality of the power storage elements of any one of the above are connected in series, wherein the power storage element module has a connection current collector unit in which an outer side current collector of one of the two power storage elements adjacent in a stacking direction and an inner side current collector of the other power storage element are integrated, and the connection current collector unit has a connection structure in which the two power storage elements adjacent in the stacking direction are fittingly connected. According to this structure, components and processes for connecting the above power storage elements, which can reduce manufacturing costs, in series with each other can be omitted, and thus the power storage element module can be further reduced in cost.

[0027] The electrode body of the present application is an electrode body formed of a plurality of unit electrode layers including a positive electrode body, a negative electrode body, and a separator sandwiched between the positive electrode body and the negative electrode body and stacked in a predetermined stacking direction, wherein two extension portions extending in a predetermined extension direction and stacked in the predetermined stacking direction are provided, and a curved portion curved so as to be connected to one end portion of each of the two extension portions and to be connected to the other extension portion by being folded back toward the other end portion as it advances from one extension portion toward one end portion in the extension direction is provided. The electrode body is formed with a through-hole passing through in the stacking direction, and has an outer side exposed surface exposed to an outer side in an opposite direction orthogonal to the extension direction and the stacking direction and electrically connected to a current collector, and an inner side exposed surface exposed to an inner side in the opposite direction and electrically connected to the current collector. This electrode body can reduce the number of components in the case of stacking a plurality of electrode bodies, and can simplify manufacturing work. Thus, the power storage element configured using this electrode body can also reduce manufacturing costs.

[0028] The manufacturing method of the power storage element of the present application includes:

[0029] A sheet preparation step of preparing a sheet-shaped positive electrode body, a sheet-shaped negative electrode body, and two separators, respectively;

[0030] A stacking step of forming an electrode stack body having a unit electrode layer in which one of the positive electrode body and the negative electrode body is stacked and arranged between the two separators, and the other of the positive electrode body and the negative electrode body is stacked and arranged outside one of the two separators;

[0031] A winding step of forming an electrode body having a plurality of the unit electrode layers in the stacking direction by winding the electrode stack body in the extension direction thereof;

[0032] An exposed edge portion setting step of setting the positive electrode body and the negative electrode body so as to have a positive electrode body exposed edge portion and a negative electrode body exposed edge portion exposed from the electrode body to an opposite direction orthogonal to the stacking direction and the extension direction, respectively;

[0033] The collector preparation step prepares an outer collector having a pair of outer opposing walls facing each other at intervals, and an inner collector having a pair of inner opposing walls facing each other at intervals inside the pair of outer opposing walls; and

[0034] The power storage element assembly step assembles the electrode body, the outer collector, and the inner collector together with the positive electrode body exposed edge portion in contact with one of the outer opposing walls and the inner opposing walls and the negative electrode body exposed edge portion in contact with the other of the outer opposing walls and the inner opposing walls.

[0035] According to this structure, as the electrode body, it is possible to form a laminated structure of a plurality of unit electrode layers in a curved configuration in which the end portions of the unit electrode layers in the extending direction are connected. Thus, it is not necessary to cut the sheet-shaped body depending on the number of unit electrode layers, and it is possible to reduce the number of components at the time of assembling the power storage element. In addition, by not performing the operation of cutting and the operation of laminating the cut sheet-shaped bodies, it is possible to reduce the number of operations.

[0036] In the manufacturing method of one embodiment of the present application, the exposed edge portion setting step can include an exposure machining step of machining the positive electrode body, the negative electrode body, and the separator or the electrode laminate to form the positive electrode exposed edge portion and the negative electrode exposed edge portion, before the winding step. According to this structure, it is possible to form the exposed edge portions without machining after the winding step. That is, although machining of the electrode body after winding can easily cause winding deviation, i.e., positional deviation of the structural layer, it is possible to avoid such deviation.

[0037] In the manufacturing method of one embodiment of the present application, the exposed edge portion setting step can include an exposure machining step of machining the positive electrode body, the negative electrode body, and the separator or the electrode laminate to form the positive electrode exposed edge portion and the negative electrode exposed edge portion, before the winding step. According to this structure, it is possible to form the exposed edge portions without machining after the winding step. That is, although machining of the electrode body after winding can easily cause winding deviation, i.e., positional deviation of the structural layer, it is possible to avoid such deviation.

[0038] The exposure machining step includes a slit machining step of forming a slit that penetrates in the thickness direction inside the positive electrode body, the negative electrode body, and the separator or the electrode laminate in the width direction,

[0039] The sheet preparation step includes a positive electrode coating step of applying a positive electrode active material to a positive electrode metal base and a negative electrode coating step of applying a negative electrode active material to a negative electrode metal base, and each of the positive electrode coating step and the negative electrode coating step includes continuously applying each active material in the extending direction in a slit outer region other than a slit region in which a slit is to be formed by the slit machining step.

[0040] According to this structure, it is possible to continuously apply the positive electrode and the negative electrode active materials to the electrode laminate in the slit outer region at the sheet preparation stage, and thus it is possible to shorten the time required for manufacturing the electrode body, as compared with the case where the active materials are applied to each sheet-shaped body cut out of the unit collector.

[0041] In the manufacturing method of one embodiment of the present application, the slit processing step can be performed after the positive electrode coating step and the negative electrode coating step. According to this structure, the active material is coated on the slit outer region of each metal base at the stage of performing the slit processing, so that the positioning of the slit is easier. Further, the active material increases the strength, so that the metal base is easily held at the time of performing the slit processing. Thus, the slit processing step can be efficiently performed.

[0042] In the manufacturing method of one embodiment of the present application, the slit processing step can be performed after the positive electrode coating step and the negative electrode coating step. According to this structure, the active material is coated on the slit outer region of each metal base at the stage of performing the slit processing, so that the positioning of the slit is easier. Further, the active material increases the strength, so that the metal base is easily held at the time of performing the slit processing. Thus, the slit processing step can be efficiently performed.

[0043] The slit processing step includes forming the slit on the positive electrode body, the negative electrode body, and the separator in the sheet preparation step,

[0044] The sheet preparation step includes forming the width direction dimension of the slit of one of the positive electrode body and the negative electrode body larger than the width direction dimension of the slit of the other, and forming the width direction dimension of the other larger than the width direction dimension of the one. According to this structure, it is easy to form the exposed edge portion after the winding step, so that the processing of the electrode body after the winding step can be omitted or simplified.

[0045] In the manufacturing method of one embodiment of the present application, the sheet preparation step can include a rolling step of rolling at least one of the positive electrode body and the negative electrode body, and the exposed edge portion setting step can include setting the positive electrode exposed edge portion and / or the negative electrode exposed edge portion to extend in a direction orthogonal to the rolling direction in the positive electrode body and / or the negative electrode body subjected to the rolling. According to this structure, the effects of cracking and increase in resistance of the surface of the positive electrode body and the negative electrode body caused by the rolling can be reduced.

[0046] Any combination of at least two structures disclosed in the claims and / or the specification and / or the drawings is included in the present application. In particular, any combination of two or more of the claims is also included in the present application. BRIEF DESCRIPTION OF DRAWINGS

[0047] The application will be more fully understood from the following description of preferred embodiments taken together with the accompanying drawings, given by way of example only. This description is not intended to limit the application in any way. The scope of the application is defined by the appended claims. In the drawings, like numbers refer to like elements throughout.

[0048] Figure 1is a longitudinal sectional view schematically showing a power storage module using a power storage element according to an embodiment of the present application.

[0049] Figure 2 is a perspective exploded view showing a power storage element module according to Figure 1

[0050] Figure 3 is a longitudinal sectional view showing a main part of a power storage element according to Figure 1

[0051] Figure 4 is a horizontal sectional view showing an internal structure of a power storage element according to Figure 1

[0052] Figure 5 is a perspective view schematically showing a modification example of an electrode body used in a power storage element according to Figure 1

[0053] Figure 6 is a plan view showing one example of a positive electrode (negative electrode) coating process included in a sheet preparation process in a method of manufacturing a power storage element according to Figure 1

[0054] Figure 7 is a plan view showing an electrode laminate made by a lamination process in a method of manufacturing a power storage element according to Figure 1

[0055] Figure 8 is a side view schematically showing a modification example in which a heat dissipation fin is provided to a flange of a power storage element according to Figure 1

[0056] Figure 9 is a horizontal sectional view showing a modification example of a configuration structure of an electrode body of a power storage element according to Figure 1

[0057] Figure 10 is a plan view schematically showing a modification example of an electrode body used in a power storage element according to Figure 1 DETAILED DESCRIPTION

[0058] An embodiment of the present application will be described below with reference to the drawings, but the present application is not limited to this embodiment.

[0059] Figure 1 is a sectional view schematically showing a configuration of a battery module B as a power storage element module according to an embodiment of the present application. Figure 2 ​​​​​​​​​is a perspective exploded view of the battery module B. The battery module B of the embodiment is configured by connecting a plurality of batteries C in series, and the battery C is a single battery as a power storage element. For example, the battery C is configured as a nickel-hydrogen secondary battery in which nickel hydroxide is used as a main positive electrode active material, a hydrogen storage alloy is used as a main negative electrode active material, and an alkaline aqueous solution is used as an electrolyte.

[0060] As shown in Figure 3 , the battery C is configured by an electrode body 13 in which a plurality of unit electrode layers 13a are stacked, a positive electrode side current collector connected to the positive electrode body 17 of the unit electrode layer 13a, and a negative electrode side current collector connected to the negative electrode body 19 of the unit electrode layer 13a.

[0061] In addition, in the present embodiment, the battery module B shown in Figure 1 is configured by physically electrically connecting the batteries to each other in a stacking direction Z described later. Specifically, the battery module is configured by electrically connecting the negative electrode side current collector of one battery CI and the positive electrode side current collector of the other battery C2 in two adjacent batteries C in series.

[0062] Specifically, the negative electrode side current collector of one battery CI and the positive electrode side current collector of the other battery C2 are formed in an integrated structure connected via a linking portion. Thus, the electrons of one battery CI can move to the electrode body 13 of the other battery via the negative electrode side current collector of one battery, the linking portion, and the positive electrode side current collector of the other battery, respectively. In addition, the current collector of the present embodiment functions as a connection current collector unit U that links one battery and the other battery.

[0063] In the present embodiment, the adjacent batteries C have the same configuration, and thus one battery CI of the adjacent batteries is mainly described, and the other battery C2 is omitted.

[0064] As shown in Figure 1As shown, in this embodiment, the battery C1 includes an outer current collector 1 constituting the positive electrode side current collector and an inner current collector 3 constituting the negative electrode side current collector. The outer current collector 1 has a pair of outer opposing walls 1a that are spaced apart from each other along a predetermined opposing direction X. The inner current collector 3 has a pair of inner opposing walls 3a that are spaced apart from each other along the opposing direction X. The pair of inner opposing walls 3a of the inner current collector 3 are disposed in the region inside the pair of outer opposing walls 1a in the opposing direction X. In other words, the inner opposing walls 3a constituting one battery C1 and the outer opposing walls 1a constituting the same battery C1 are positioned at an overlap along the stacking direction Z when viewed from the opposing direction X. In other words, the inner opposing walls 3a constituting one battery C1 and the outer opposing walls 1a constituting the same battery C1 are formed to be able to contact the electrode body 13 constituting one battery C1, respectively.

[0065] In this specification, the opposing direction X of the pair of outer opposing walls 1a configured as described above is simply referred to as the "opposing direction X". Furthermore, in this specification, the direction in which the unit electrode layer 13a is stacked is referred to as the "stack direction Z". The opposing direction X is a direction orthogonal to the stack direction Z. Moreover, in this specification, the direction orthogonal to both the opposing direction X and the stack direction Z is referred to as the "extending direction Y".

[0066] The electrode body 13 of battery C1 is disposed in a receiving region 11, which includes an inter-wall space 11a formed between a pair of outer opposing walls 1a and a pair of inner opposing walls 3a. An electrolyte is also contained in the receiving region 11 along with the electrode body 13. In this embodiment, the electrode body 13 is formed as a ring around an axis extending along the stacking direction Z. Thus, the electrode body 13 is covered by and opposite the outer opposing walls in the opposing direction X, and covers and opposite the inner opposing walls 3a in the opposing direction X. Figure 3 As shown, the electrode body 13 has multiple parallel unit electrode layers 13a stacked along the stacking direction Z. Each unit electrode layer 13a individually contacts the current collectors 1 and 3. Specifically, the unit electrode layer 13a contacts opposing walls 1a and 3a opposite each other along the opposing direction X. Thus, each unit electrode layer 13a is electrically connected in parallel with the current collectors. Therefore, each of these unit electrode layers 13a is configured to contact the outer opposing wall 1 and the inner opposing wall 3a constituting a battery C1, respectively.

[0067] Furthermore, as described above, in this embodiment, Figure 1The inner-side current collector 3 of one of the two adjacent batteries C1, C2 and the outer-side current collector 1 of the other battery C2 are integrated to form a connection current collector unit U. In the connection current collector unit U, the pair of outer-side opposing walls la and the pair of inner-side opposing walls 3a are disposed at positions not overlapping in the direction of opposition X. In other words, the inner-side opposing wall 3a constituting one connection current collector unit U is disposed at a position offset in the direction of stacking Z with respect to the outer-side opposing wall la constituting the same connection current collector unit U. In other words, one connection current collector unit U is configured to be capable of contacting the outer-side portion in the direction of opposition X of the electrode body 13 of one of the two adjacent batteries C1, C2 and the inner-side portion in the direction of opposition X of the electrode body 13 of the other battery C2, respectively.

[0068] More specifically, as shown in Figure 2 The connection current collector unit U in the present embodiment has a peripheral wall portion 5, a peripheral cover portion 7, an inner peripheral wall portion 9, and an inner peripheral cover portion 10. The peripheral wall portion 5 includes a pair of outer-side opposing walls la. The peripheral wall portion 5 is formed in a shape covering the electrode body 13 at least in the direction of opposition X. In the present embodiment, the peripheral wall portion 5 is formed in a cylindrical shape winding one turn around an axis extending in the direction of stacking Z. In addition, the peripheral wall portion 5 has the pair of outer-side opposing walls and a pair of outer-side connecting walls 12 connecting both ends of the extending direction Y of the pair of outer-side opposing walls, respectively.

[0069] In the present embodiment, the peripheral wall portion 5 is formed in a rectangular cylindrical shape. The pair of outer-side opposing walls la is formed in a plate shape extending in an imaginary plane perpendicular to the direction of opposition X. In addition, the pair of outer-side connecting walls 12 is formed in a plate shape extending in an imaginary plane perpendicular to the extending direction Y. The outer shape of the peripheral wall portion 5 is formed in a rectangular shape in which the size in the extending direction Y is larger than the size in the direction of opposition X, as viewed in the direction of stacking Z. In other words, the size in the extending direction Y of the outer-side opposing wall la is formed to be larger than the size in the direction of opposition X of the outer-side connecting wall 12. In addition, the size in the direction of stacking Z of the outer-side opposing wall la is formed to be the same as the size in the direction of stacking Z of the outer-side connecting wall 12, and is formed to be larger than the size in the direction of stacking Z of the electrode body 13.

[0070] The peripheral cover portion 7 includes a connecting portion connecting the outer-side opposing wall la and the inner-side opposing wall 3a on one side in the direction of stacking Z. In addition, the peripheral wall portion 5 includes a connecting portion connecting the pair of outer-side opposing walls la on one side in the direction of stacking Z. In the present embodiment, the peripheral cover portion 7 is formed in a cover shape covering one side in the direction of stacking Z of the peripheral wall portion 5. The peripheral cover portion 7 connects the peripheral edge portion of one end side in the direction of stacking Z in the peripheral wall portion 5 over the entire circumference thereof. Thus, the outer shape of the peripheral cover portion 7 is formed in a rectangular shape as viewed in the direction of stacking Z.

[0071] The inner wall portion 9 includes a pair of inner side walls 3a. The inner wall portion 9 is provided so as to protrude from the outer lid portion 7 toward one side in the stacking direction Z (the side opposite the outer side wall la with respect to the outer lid portion 7). The inner wall portion 9 is formed in a shape covered by the electrode body 13 at least in the direction X. In the present embodiment, the inner wall portion 9 is formed in a cylindrical shape that surrounds one turn around an axis extending in the stacking direction Z. In addition, the inner wall portion 9 has the inner side walls 3a described above and a pair of inner link walls 14 that link both ends of the extension direction Y of the pair of inner side walls 3a, respectively.

[0072] In the present embodiment, the inner wall portion 9 is formed in a rectangular cylindrical shape. The pair of inner side walls 3a is formed in a plate shape extending in an imaginary plane perpendicular to the direction X. In addition, the pair of inner link walls 14 is formed in a plate shape extending in an imaginary plane perpendicular to the direction Y. The outer shape of the inner wall portion 9 is formed in a rectangular shape in which the dimension in the direction Y is larger than the dimension in the direction X, as viewed in the stacking direction Z. In other words, the dimension in the direction Y of the inner side walls 3a is formed to be larger than the dimension in the direction X of the inner link walls 14. In addition, the dimension in the stacking direction Z of the inner side walls 3a is formed to be the same as the dimension in the stacking direction Z of the inner link walls 14, and is formed to be larger than the dimension in the stacking direction Z of the electrode body 13.

[0073] The inner lid portion 10 includes a link portion that links the pair of outer side walls la and the inner side walls 3a on one side in the stacking direction Z. In addition, the inner wall portion 9 includes a link portion that links the pair of inner side walls 3a on one side in the stacking direction Z. In the present embodiment, the inner lid portion 10 is formed in a lid shape that covers one side in the stacking direction Z of the inner wall portion 9. The inner lid portion 10 connects the peripheral portion of one end side in the stacking direction Z in the inner wall portion 9 over the entire circumference. Thus, the outer shape of the inner lid portion 10 is formed in a rectangular shape as viewed in the stacking direction Z. The inner lid portion 10 can also be formed with a through-hole that penetrates in the stacking direction Z. Thereby, it is possible to prevent the accommodation space from being closed, and thus prevent the influence of expansion / contraction of the filled fluid in the accommodation space due to temperature changes.

[0074] Thus, in the present embodiment, the outer wall portion 5 and the inner wall portion 9 are formed in a substantially rectangular shape as viewed from the outside in the stacking direction Z. The inner wall portion 9 constitutes the inner current collector 3 of one battery Cl, and the outer wall portion 5 constitutes the outer current collector 1 of another battery C2. In addition, in the present embodiment, the outer wall portion 5 and the inner wall portion 9 have walls (outer link walls 12, inner link walls 14) that oppose each other in addition to the outer side walls la and the inner side walls 3a because they are each substantially rectangular cylindrical shapes, but in the present specification, only the walls that can contact the positive electrode body 17 and the negative electrode body 19 to collect current are referred to as the "outer side walls la" and the "inner side walls 3a".

[0075] As shown in FIG. 1, the battery module B is configured in such a manner that a pair of inner side opposite walls 3a of another connecting current collector unit U2 are arranged in opposition to a pair of outer side opposite walls la of one connecting current collector unit Ul on the inner side of the outer side opposite walls la of the one connecting current collector unit Ul. Specifically, by fitting the outer side opposite walls la to the outer side of the electrode body 13 and fitting the inner side opposite walls 3a to the inner side of the electrode body 13, a connecting configuration in which the batteries C are connected to each other is achieved. Figure 1

[0076] By using the connecting current collector unit U configured in this manner, the connecting current collector units U can be connected to each other via the electrode body 13 to physically and electrically connect a plurality of batteries C. As a result, components for connecting the batteries C in series with each other can be omitted, and thus the battery module B can be downsized and reduced in cost.

[0077] In the present embodiment, a space partitioned by the pair of outer side opposite walls la of the first connecting current collector unit Ul, the peripheral cover portion 7 of the first connecting current collector unit Ul, the pair of inner side opposite walls 3a of the second connecting current collector unit U2, and the peripheral cover portion 7 of the second connecting current collector unit U2 forms the accommodation region 11.

[0078] Further, between the outer side current collectors 1 of the first connecting current collector unit Ul and the outer side current collectors 1 of the second connecting current collector unit U2, an insulating sealing member 15 made of an insulating material can be fitted. With the insulating sealing member 15, electrical insulation between the adjacent batteries C is ensured. Alternatively, instead of the insulating sealing member, an insulating partition that prevents the outer side current collectors from contacting each other can be provided.

[0079] As shown in FIG. 1, the electrode body 13 is configured by a sheet-shaped electrode laminate 43 including a positive electrode body 17, a negative electrode body 19, and a separator 21 fitted between the positive electrode body 17 and the negative electrode body 19. Figure 3 Figure 7 The electrode body 13 is configured such that unit electrode layers 13a adjacent in the stacking direction Z are connected by being bent at the end portions in the extending direction Y. More specifically, the electrode body 13 is formed by thinning the thickness dimension after winding the electrode laminate 43 and shaping the cross section perpendicular to the opposite direction X to be flat and into a substantially rectangular shape.

[0080] ​​In this embodiment, the electrode body 13 is formed into a rectangular plate shape by winding a sheet-like electrode stack 43. The electrode body 13 is arranged such that its thickness direction is along the stacking direction Z, and its long side on the surface perpendicular to the thickness direction is along the extending direction Y, and its short side on the surface perpendicular to the thickness direction is along the opposing direction X. The electrode body 13 is arranged such that the exposed layer surface showing the overlapping of the unit electrode layer 13a faces the opposing direction X. The exposed layer surface of the electrode body 13 is the outer exposed surface that contacts the outer opposing wall 1a.

[0081] The electrode body 13 has a through hole 23 extending along the thickness direction, i.e., the stacking direction Z, for fitting into the inner opposing wall 3a. The through hole 23 is formed as an elongated hole extending along the extension direction Y, and is formed in the middle portion of the opposing direction X in the electrode body 13, specifically at the central position of the opposing direction X. The surface of the electrode body 13 exposed along the opposing direction X toward the through hole 23 is the inner exposed surface that contacts the inner opposing wall 3a.

[0082] like Figure 3 As shown, the unit electrode layer 13a is configured to include sheet-shaped positive electrode 17, sheet-shaped negative electrode 19 arranged along the stacking direction Z and parallel to the opposing direction X, and sheet-shaped separator 21 sandwiched between these positive electrode 17 and negative electrode 19. In the inter-wall space 11a, multiple unit electrode layers 13a are arranged along the stacking direction Z. In other words, multiple unit electrode layers 13a are stacked along the thickness direction of the electrode body 13 (inter-wall space 11a, i.e., the height direction of the receiving region 11). The portion of the electrode body 13 thus formed, excluding the two ends 13b extending in the Y direction, is the portion where multiple unit electrode layers 13a are stacked together.

[0083] like Figure 3 As shown, the positive electrode 17 has a positive electrode exposed portion that extends outward from the excess portion constituting the unit electrode layer 13a in the opposing direction X. The negative electrode 19 has a negative electrode exposed portion that extends inward from the excess portion constituting the unit electrode layer 13a in the opposing direction X. Thus, the positive electrode exposed portion and the negative electrode exposed portion 19 are exposed in opposite directions, either inward or outward, in the opposing direction X. The positive electrode 17 is electrically connected to the outer current collector 1 by contacting the positive electrode exposed edge 17a with the outer opposing wall 1a. The negative electrode 19 is electrically connected to the inner current collector 3 by contacting the negative electrode exposed edge 19a with the inner opposing wall 3a.

[0084] Thus, exposed edges 17a and 19a are respectively provided on the positive electrode 17 and the negative electrode 19. By contacting the exposed edges 17a and 19a with the opposing walls 1a and 3a, the electrical connection between the electrode body 13 and each current collector 1 and 3 is ensured. In other words, by fitting and contacting the outer opposing wall 1a and the inner opposing wall 3a with the electrode body 13, the connection between the batteries C and the current collectors 1 and 3 and the electrode body 13 can be achieved in two steps. Therefore, no additional operations are required to connect the electrode body 13 with the current collectors 1 and 3, and the manufacturing quantity of battery module B per unit time can be increased.

[0085] The multiple unit electrode layers 13a adjacent to each other along the stacking direction Z of the electrode body 13 have portions with the same length in the extending direction Y. This allows the end face of the unit electrode layer 13a in the opposing direction X to be formed as a straight line. This facilitates surface contact between the electrode body 13 and the opposing wall, suppressing poor contact between the electrode body 13 and the current collectors 1 and 3. For example, by forming portions with the same length in the opposing direction X of the multiple unit electrode layers 13a adjacent to each other along the stacking direction Z, the end face of the current collectors 1 and 3 in the opposing direction X can be formed as a plane. This facilitates surface contact between the electrode body 13 and the opposing wall, further suppressing poor contact between the electrode body 13 and the current collectors 1 and 3.

[0086] More specifically, each unit electrode layer 13a of the electrode body 13, when viewed from the stacking direction Z (i.e., when viewed from above), is formed into a rectangular shape with sides along the extension direction Y and the opposing direction X, respectively. This increases the volumetric energy density per unit cubic space, making it easier to increase the output power. Furthermore, as described above, the outer current collector 1 and the inner current collector 3 of the housing region 11 used to form the electrode body 13 are also formed into a generally cuboid shape corresponding to the shape of the electrode body 13. By configuring the electrode body 13 and the current collectors 1 and 3 in this way, the space for the battery C and battery module B can be effectively utilized, preventing the battery from becoming too large.

[0087] In this embodiment, the electrode body 13 has a surface orthogonal to the opposing direction X that is larger than the surface orthogonal to the extending direction Y. This increases the area in contact with the current collectors 1 and 3 within a unit electrode layer 13a, thereby reducing resistance. Furthermore, the through-hole 23 of the electrode body 13 is formed as an elongated hole extending along the extending direction Y. Figure 4 As shown, the length of the extension direction Y of the through hole 23 is made larger than the length of the extension direction Y of the inner opposing wall 3a. According to this structure, when the electrode body 13 is bent, sufficient margin can be ensured for reliable contact with the inner opposing wall 3a to accommodate the positional offset generated in the through hole 23, and poor contact between the electrode body 13 and the inner opposing wall 3a can be prevented.

[0088] In addition, as shown in the figure, the dimension in the direction of opposition X is set to be shorter than the dimension in the direction of extension Y in the electrode body 13. By making the dimension in the direction of opposition X of the electrode body 13 short, the distance over which the charged particles move to the current collector in the electrode body 13 can be made short, and thus the internal resistance of the battery is reduced.

[0089] In the present embodiment, as described above, the outer side opposing wall la is formed as a positive electrode current collector, and the inner side opposing wall 3a is formed as a negative electrode current collector. In the battery C of the present embodiment, the area of one of the positive electrode body and the negative electrode body that contacts the inner side opposing wall 3a is made small. Thus, in the case where a more expensive material is used for the negative electrode active material as in the nickel-hydrogen secondary battery of the present embodiment, by making the inner side opposing wall 3a the negative electrode current collector as in this example, the cost of the raw materials for the entire battery can be reduced.

[0090] In the present embodiment, the electrode body 13 is provided in a rolled shape, and can be formed by a process of rolling the positive electrode body 17, the negative electrode body 19, and the separator 21, and thus the electrode body 13 can be manufactured in a short time compared to the electrode body 13 of the folding type described later. In addition, in the electrode body 13 of the rolled shape, the end surface in the direction of extension Y can be prevented from being formed in a concavo-convex shape.

[0091] In the present embodiment, by joining the pair of outer side opposing walls la with the peripheral connecting wall, respectively, in the case of fitting the electrode body 13, the deformation in the direction of opposition X of the outer side opposing wall la can be prevented, and contact failure can be easily prevented. Similarly, by joining the pair of outer side opposing walls la with the peripheral cover 7, respectively, in the case of fitting the electrode body 13, the deformation in the direction of opposition X of the outer side opposing wall la can be prevented, and contact failure can be easily prevented.

[0092] By making the curved portion of the end portion in the direction of extension Y of the electrode body 13 also contact the outer side opposing wall la, the contact area of the electrode body 13 with the current collector can be increased. Also, the electrode body 13 and the current collector of the present embodiment are in surface contact with flat surfaces, and thus the contact can be made more reliably compared to the case of surface contact with curved surfaces.

[0093] In addition, in the present embodiment, the sheet-like unit electrode layer 13a is configured so as to be connected at the end portion in the direction of extension Y, and thus the electrode body 13 can be handled as one unit, and in the case of failure or deterioration, the electrode body 13 can be prevented from being separated for each unit electrode layer 13a, and the replacement of the electrode body 13 is easy. At the time of disassembly, the positive electrode layer, the negative electrode layer, and the separator can be easily separated, and recycling processing and the like can be easily achieved.

[0094] Further, the specific form of the electrode body 13 of the battery C of the present embodiment is not limited to the rolled type described above. For example, as shown in Figure 5 the electrode layer stack 43 described above can be stacked in the direction of opposition X of the electrode body 13, and the electrode body 13 can be formed by joining the outer side opposing walls la with the peripheral connecting wall, and the peripheral cover 7, respectively.Figure 7 The electrode body 13 is formed by repeatedly folding along the extension direction Y, such that the positive electrode 17, negative electrode 19, and separator 21 of adjacent unit electrode layers 13a are connected at their respective ends 13b in the extension direction Y, thereby forming a bent electrode body 13. Alternatively, the electrode body 13 may have a structure in which plate-shaped positive and negative electrodes are alternately stacked between separators folded into pleats. In the case of such a folded electrode body 13, it can also be formed into an annular shape with a through hole 23 extending along the stacking direction Z. By making the electrode body 13 a folded structure, it is easy to prevent the large size of the extension direction Y, even when the number of stacked units of electrode layer 13a is increased by repeated folding.

[0095] Furthermore, although the illustrations are omitted, the battery C and battery module B described above can have the following structures.

[0096] Battery C and battery module B can be configured to be covered by a casing made of insulating material. Furthermore, battery module B can have positive and negative terminals. The positive and negative terminals of battery module B are respectively connected to the positive and negative current collectors at both ends of the stacking direction Z of the multiple batteries C connected in series by stacking. Additionally, in battery module B, a fastening mechanism such as bolts can be used to apply pressure to the multiple batteries C along the stacking direction Z.

[0097] Next, an example of a method for manufacturing a battery C having the wound electrode body 13 of this embodiment will be described.

[0098] The manufacturing method of this embodiment includes a sheet preparation process, a lamination process, a winding process, an exposed edge setting process, a current collector preparation process, and a battery assembly process.

[0099] In the sheet preparation process, a strip-shaped and sheet-shaped positive electrode 17, a negative electrode 19, and two diaphragms 21 are respectively equipped.

[0100] More specifically, such as Figure 6 As shown, the sheet preparation process includes a positive electrode coating process for coating positive electrode active material 17c onto a positive electrode substrate 17b and a negative electrode coating process for coating negative electrode active material 19c onto a negative electrode substrate 19b. Specifically, as shown in the figure, the positive electrode coating process and the negative electrode coating process are performed by continuously attaching a slurry containing active materials 17c and 19c to the sheet-shaped metal substrates 17b and 19b along the extension direction Y using a coating device equipped with a doctor blade 41.

[0101] Thus, in the battery C of this embodiment, the positive electrode active material 17c (nickel hydroxide in this embodiment) is attached to the positive electrode substrate 17b made of a conductive material, thereby forming the positive electrode 17. The negative electrode active material 19c (hydrogen storage alloy in this embodiment) is attached to the negative electrode substrate 19b made of a conductive plate-shaped component, thereby forming the negative electrode 19. Separator 21 ( Figure 2 It is formed by an insulating porous membrane. The electrolyte is immersed in the membrane 21.

[0102] The positive electrode substrate 17b and the negative electrode substrate 19b are made of foil formed from nickel-plated steel sheets, but they are not limited to this. Appropriate materials can be selected considering factors such as electrochemical properties, mechanical strength, and corrosion resistance. In addition, the positive electrode substrate 17b and the negative electrode substrate 19b can also be made of different materials.

[0103] As the material for forming the diaphragm 21, for example, polyolefin fibers such as polyethylene fibers and polypropylene fibers, polyphenylene sulfide fibers, polyvinyl fluoride fibers, polyamide fibers, etc. can be used.

[0104] In addition, as the electrolyte for immersing the separator 21, alkaline aqueous solutions commonly used in nickel-metal hydride secondary batteries, such as KOH aqueous solution, NaOH aqueous solution, LiOH aqueous solution, etc., can be used. In particular, it is preferable to use a material obtained by immersing the separator 21 in a sheet by making a substance that imparts viscosity to the KOH aqueous solution with added potassium acrylate and adjusts it into a gel state.

[0105] As a formation Figure 1 The insulating material of the insulating sealing component 15 shown is polypropylene resin in this embodiment, but it is not limited to this. Various materials can be selected from the perspectives of mechanical strength, heat resistance, electrolyte resistance, etc.

[0106] In this embodiment, the sheet preparation process further includes a rolling process for rolling the positive electrode 17 and the negative electrode 19, respectively. Through this rolling process, the sheet-like and strip-like positive electrode 17 and negative electrode 19 are compressed along the thickness direction and stretched along the width direction. Through this rolling process, the active material in the positive electrode 17 and negative electrode 19 becomes difficult to peel off from the matrix. Of course, only one of the positive electrode 17 and negative electrode 19 may be rolled, or the rolling process may be omitted.

[0107] In the lamination process, such as Figure 7 As shown, a strip-shaped electrode stack 43 is formed having a unit electrode layer 13a, wherein one of the positive electrode 17 and the negative electrode 19 is stacked between two diaphragms 21, and the other of the positive electrode 17 and the negative electrode 19 is stacked on the outside of one of the two diaphragms 21.

[0108] In the winding process, the electrode laminate 43 in a band shape is wound along the extending direction Y thereof, and an electrode body 13 having a plurality of unit electrode layers 13a in the stacking direction Z is formed. Figure 2 ).

[0109] In the exposed edge portion setting process, the positive electrode body 17 and the negative electrode body 19 are set so as to have a positive electrode body exposed edge portion 17a and a negative electrode body exposed edge portion 19a, respectively, which are exposed from the electrode body 13 in a direction orthogonal to the stacking direction Z.

[0110] In the present embodiment, the exposed edge portion setting process can also include an exposure machining process of machining the positive electrode body 17, the negative electrode body 19, and the separator 21 or the electrode laminate 43 to form the positive electrode exposed edge portion and the negative electrode exposed edge portion, before the winding process.

[0111] More specifically, the exposure machining process includes, for example, a slit machining process. In the slit machining process, a plurality of slits 45 that pass through in the thickness direction are formed in the width direction inner side of the positive electrode body 17, the negative electrode body 19, and the separator 21 or the electrode laminate 43. In the winding process, the positive electrode body 17, the negative electrode body 19, and the separator 21 are wound so as to be stacked in a plurality of layers in a manner that the slits 45 formed in each of them overlap, and a through-hole 23 is formed in the electrode body 13 as shown in Figure 2 .

[0112] In the slit machining process, in a case where the slits 45 are formed in the positive electrode body 17, the negative electrode body 19, and the separator 21, the positive electrode coating process and the negative electrode coating process include, respectively, continuously coating the positive electrode active material 17c and the negative electrode active material 19c in the extending direction Y in a slit outer region other than a slit region 47 in which the slit 45 is to be formed by the slit machining process, as shown in Figure 6 . Specifically, in the present embodiment, in the central portion in the width direction of the positive electrode body 17, the slit 45 shown by the broken line in the drawing is formed. In the region of the positive electrode body 17 other than the slit region 47 in which the slit 45 is to be formed, the positive electrode active material 17c is continuously coated in the extending direction Y in the width direction range from the portions slightly separated from both width direction sides of the slit region 47 to the portions other than the both outer edge portions. In the negative electrode coating process, the negative electrode active material 19c is also continuously coated in substantially the same range.

[0113] However, as described above, in this embodiment, in the completed battery C, the positive electrode 17 is in contact with the outer opposing wall 1a, and the negative electrode 19 is in contact with the inner opposing wall 3a. Therefore, the width of the positive electrode 17 is set to be larger than the width of the negative electrode 19. Furthermore, the width of the slit region 47 of the positive electrode 17 is set to be larger than the width of the slit region 47 of the negative electrode 19. Additionally, the width of the separator 21 is set to be the midpoint between the width of the positive electrode 17 and the width of the negative electrode 19, and the width of the slit in the separator 21 is set to be the midpoint between the width of the slit in the positive electrode 17 and the width of the slit in the negative electrode 19. By setting the dimensions of the positive electrode 17, the negative electrode 19, and the separator 21 in this way, the exposed edge portion 17a and the exposed edge portion 19a of the positive electrode can be formed by overlapping and winding them with their centers aligned in the width direction. The size setting of the slit 45, which includes the positive electrode 17, the negative electrode 19 and the separator 21, constitutes the exposure processing procedure.

[0114] Furthermore, in the case where the slit processing process is performed before the winding process, the spacing of the extension direction Y between the multiple slits 45 is set based on the fact that the size of the electrode body 13 increases along the extension direction Y due to repeated winding.

[0115] Furthermore, with the positive electrode exposed edge 17a and the negative electrode exposed edge 19a configured in this way, in each of the strip-shaped positive electrode 17 and negative electrode 19, each exposed edge 17a and 19a is configured to extend along an extension direction Y (length direction) orthogonal to the width direction. If the sheet preparation process also includes a rolling process as described above, each exposed edge 17a and 19a will extend in a manner orthogonal to the width direction (opposite direction X), i.e., the rolling direction. By rolling the positive electrode 17 and negative electrode 19, and setting the extension direction of the exposed edges in the positive electrode 17 and negative electrode 19 to be orthogonal to the compression direction, and by collecting current through each exposed edge 17a and 19a configured in this way, the effects of surface cracking and increased resistance of the positive electrode 17 and negative electrode 19 that may occur due to rolling can be reduced.

[0116] After the positive electrode coating process and the negative electrode coating process, the above-mentioned slit processing process is performed.

[0117] In the current collector preparation process, preparation Figure 1 The outer current collector 1 and the inner current collector 3 shown are provided. The outer current collector 1 has a pair of outer opposing walls 1a, 1a that are spaced apart from each other. The inner current collector 3 has a pair of inner opposing walls 3a, 3a that are disposed inside the pair of outer opposing walls 1a, 1a and are spaced apart from each other in the opposing direction X of the pair of outer opposing walls 1a, 1a.

[0118] As for the metal material forming the outer collector 1 and the inner collector 3, a material capable of stable use for a long period is selected in consideration of the electrochemical characteristics of each active material of the positive and negative electrodes with which each collector comes into contact for current collection, and the like. For example, in the case where the battery C is configured as a nickel-hydrogen secondary battery as in the present embodiment, both the outer collector 1 and the inner collector 3 can be formed of, for example, a steel sheet on which nickel plating is performed. On the other hand, in the case where the battery C is configured as a lithium-ion secondary battery, the collector that becomes the positive electrode side collector (the outer collector 1 in the present embodiment) is formed of, for example, an aluminum sheet, and the collector that becomes the negative electrode side collector (the inner collector 3 in the present embodiment) is formed of a copper sheet or a nickel-plated steel sheet.

[0119] In addition, in the present embodiment, in the collector preparation process, more specifically, as shown in Figure 1 , a plurality of connection collector units U are produced. In the case where both the outer collector 1 and the inner collector 3 are formed of the same material, for example, the nickel-plated steel sheet described above, the connection collector units U are produced, for example, by performing press working on the nickel-plated steel sheet. In the case where the outer collector 1 and the inner collector 3 are formed of different materials, for example, the aluminum sheet and the copper sheet described above, the connection collector units U are produced by performing press working on these sheet materials in a superposed state.

[0120] In the battery assembly process, the electrode body 13, the outer collector 1, and the inner collector 3 are assembled in such a manner that the positive electrode body exposed edge portion 17a comes into contact with one of the outer facing wall 1a and the inner facing wall 3a, and the negative electrode body exposed edge portion 19a comes into contact with the other of the outer facing wall 1a and the inner facing wall 3a.

[0121] After the battery assembly process, a liquid injection process of injecting an electrolyte into the accommodation region 11 is performed. The injection of the electrolyte is performed, for example, via an injection hole (not shown) provided in the top wall of the protruding wall portion 9.

[0122] In the battery C of the present embodiment, on each face of the outer facing wall 1a and the inner facing wall 3a that comes into contact with the electrode body 13, a concavo-convex that prevents positional displacement of the positive electrode body 17 and the negative electrode body 19 is preferably formed. More specifically, the inner peripheral face of the outer facing wall 1a and the outer peripheral face of the inner facing wall 3a are each formed as a rough face on which a fine concavo-convex is formed. Such a concavo-convex can be formed, for example, by composite plating or segmented press working. With this structure, it is possible to prevent positional displacement of the electrode body 13 with respect to the collector, and it is possible to prevent poor contact of the collector with the electrode layer. Furthermore, the concavo-convex for preventing positional displacement can be provided only on either of the outer facing wall 1a and the inner facing wall 3a, or can be omitted.

[0123] As shown in Figure 4As shown in the present embodiment, a reinforcing mechanism that prevents deformation in the direction of opposition X can also be provided on the current collectors 1, 3. More specifically, as the reinforcing mechanism, a plurality of reinforcing ribs 25 that extend in a direction orthogonal to the extending direction Y can be provided at equal intervals on the outer circumferential surface of the outer side opposing wall la and the inner circumferential surface of the inner side opposing wall 3a, which are the surfaces on the side of each opposing wall that does not contact the positive electrode body 17 and the negative electrode body 19, respectively. With this structure, deformation of each opposing wall la, 3a can be prevented, and thus contact failure due to deformation can be prevented. Furthermore, the reinforcing mechanism can be provided on only one of the outer side opposing wall la and the inner side opposing wall 3a, or can be omitted. In addition, the specific form of the reinforcing mechanism is not limited to the reinforcing ribs 25 of the example.

[0124] In the present embodiment, the region of the outer side current collector 1 other than the region that contacts the positive electrode body 17 in the connected state, i.e., the region of the inner circumferential surface of the outer side opposing wall la other than the inner circumferential surface of the peripheral wall portion 5 in the example shown in the drawing, can also be covered with the insulating material 27. The region of the inner side current collector 3 other than the region that contacts the negative electrode body 19 in the connected state, i.e., the region of the outer circumferential surface of the inner side opposing wall 3a other than the outer circumferential surface of the protruding wall portion 9, can also be covered with the insulating material 27 instead of the above-mentioned region of the outer side current collector 1 or in addition to the above-mentioned region. By covering the current collectors 1, 3 in this way, short-circuiting between the electrode body 13 and each current collector 1, 3 can be prevented.

[0125] In the present embodiment, as shown in Figure 1 and Figure 4 , a flange 29 is provided on the opening side edge portion of the outer side current collector 1. By providing the flange 29 in this way, the edge functions as a cooling fin, and thus the heat dissipation of the connected current collector unit U, including the outer side current collector 1, is improved, and the temperature increase of the battery C during charge and discharge can be suppressed. Furthermore, as shown in Figure 8 as a modification, a cooling fin 31 can also be provided by folding a portion of the flange 29 after cutting it. The shape, number, and location at which the cooling fin 31 is provided are not limited to the example shown in the drawing. Of course, the flange 29 can also be omitted. In the case where the flange 29 is omitted, the size of the entire battery module B constituted by the battery C is smaller, and the volumetric energy density can be improved.

[0126] In addition, in the present embodiment, as shown in Figure 2 , a through hole 23 is formed in one electrode body 13. Of course, the manner in which the electrode body 13 is arranged in the accommodation region 11 is not limited to the example described above. For example, as shown in Figure 9As a modification, as shown in FIG. 12, the two electrode bodies 13 formed separately from each other can be arranged in the pair of wall space 11a. In other words, the electrode body 13 can be arranged in a portion other than the extension direction Y side of the through hole 23. Further, it is not necessary that the electrode body 13 is arranged in each of the pair of wall space 11a, but the electrode body 13 can be arranged in the housing region wall space 11a of only one side.

[0127] Further, in the case where the through hole 23 is formed in one electrode body 13, the number of the through hole 23 is not limited to one, but a plurality of through holes 23 can be formed along the extension direction Y. In this case, the pair of inner opposing walls 3a, 3a are intermittently arranged along the extension direction Y in correspondence with the number and position of the plurality of through holes 23 of the electrode body 13. In the case where a plurality of through holes 23 are thus formed, it is easy to prevent the positional displacement of the electrode body 13 in the extension direction Y.

[0128] Further, in the present embodiment, the example in which the shape of the electrode body 13 is set to be substantially rectangular in plan view and the shapes of the outer collector 1 and the inner collector 3 are also set to be substantially rectangular in plan view in correspondence therewith is described. However, the electrode body 13 can be curved by connecting the positive electrode body 17, the negative electrode body 19, and the separator 21 of the adjacent unit electrode layer 13a at the end 13b in the extension direction Y, respectively, and the shape thereof is not limited to the above-described example, but can be substantially circular in plan view, for example, as shown in FIG. 13. Figure 10

[0129] Further, in the present embodiment, the outer collector 1 is formed as a positive electrode side collector and the inner collector 3 is formed as a negative electrode side collector, but the positive electrode side and the negative electrode side can be exchanged, the outer collector 1 can be formed as a negative electrode side collector, and the inner collector 3 can be formed as a positive electrode side collector.

[0130] Further, in the present embodiment, the example in which a plurality of batteries C1, C2 are connected in series to constitute the battery module B is shown, but it is not necessary to use as the battery module B, but a single battery C can be used alone. In this case, the effects already described with respect to the present embodiment can be obtained.

[0131] Further, the shapes of the peripheral wall portion 5 and the inner wall portion 9 shown in the present embodiment are merely one example, and other shapes can be used. For example, the through hole 23 can be formed locally on the peripheral wall portion 5 and the inner wall portion 9, and a configuration in which the through hole 23 is not provided locally and intermittently can be used. Further, in the present embodiment, the peripheral wall portion 5 and the inner wall portion 9 are formed by walls extending in parallel along the stacking direction Z, but can be tapered shapes that are inclined to the opposite direction X as they progress in the stacking direction Z.

[0132] ​In addition, not only the battery and the battery module B, but also the electrode body 13 having the above-described structure is included in the scope of the present application.

[0133] According to the battery C and the manufacturing method thereof of the above-described embodiment, in the case where a plurality of batteries C are connected in series, by integrally forming or electrically connecting the outer-side current collector 1 of one battery C with the inner-side current collector 3 of another battery C, they can be easily and compactly connected. In the battery C of such a current collecting structure, as the electrode body 13, by adopting the electrode body 13 of a bent structure in which the unit electrode layers 13a are connected at the end portions 13b in the extending direction Y, for example, the electrode body 13 of a wound structure, it is not necessary to cut the sheet-shaped body according to the number of the unit electrode layers 13a, and the number of components can be reduced at the time of battery assembly. In addition, by not requiring the work of cutting and the work of stacking the cut sheet-shaped bodies, the number of works can be reduced. In this way, the number of the electrode bodies 13 that can be manufactured per unit time can be increased.

[0134] Further, the above-described embodiment is described as an example in which the battery module B is configured of nickel-hydrogen secondary batteries, but the present application is not limited thereto, and can be applied to various primary batteries and secondary batteries, for example, nickel-cadmium secondary batteries, lithium-ion secondary batteries, and the like.

[0135] In addition, in the above-described embodiment, as one example of the power storage element, a battery is used, but the present application can also be applied to power storage elements other than batteries, for example, lithium-ion capacitors.

[0136] The above-described preferred embodiments of the present application have been described with reference to the drawings, but various additions, changes, or deletions can be made within the scope of the gist of the present application. Thus, such a scheme is also included in the scope of the present application.

[0137] Explanation of Reference Numerals

[0138] 1 outer-side current collector

[0139] 1a outer-side opposing wall

[0140] 3 inner-side current collector

[0141] 3a inner-side opposing wall

[0142] 13 electrode body

[0143] 13a unit electrode layer

[0144] 17 positive electrode body

[0145] 17a positive electrode body exposure edge portion

[0146] 19 negative electrode body

[0147] 19a negative electrode body exposure edge portion

[0148] 21 separator

[0149] 23 through hole

[0150] 43 electrode laminate

[0151] B battery module (power storage element module)

[0152] C battery (power storage element)

[0153] U connecting current collector unit

[0154] X opposite direction

[0155] Y extending direction

[0156] Z stacking direction

Claims

1. A power storage element comprising: an outer current collector having a pair of outer opposing walls opposing each other at intervals along a predetermined opposing direction; an inner current collector having a pair of inner opposing walls disposed inside the opposing direction of the pair of outer opposing walls and opposing each other at intervals along the opposing direction; and an electrode body disposed in a space formed between the pair of outer opposing walls and the pair of inner opposing walls, wherein The electrode body is configured to form unit electrode layers stacked in a predetermined stacking direction orthogonal to the facing direction by stacking a sheet-like electrode laminate including a positive electrode body, a negative electrode body, and a separator sandwiched between the positive electrode body and the negative electrode body, and to connect the unit electrode layers adjacent in the stacking direction to each other by bending end portions in an extension direction orthogonal to the stacking direction and the facing direction. The positive electrode bodies arranged in the stacking direction are electrically connected to a current collector by contacting the current collector as either one of the outer current collector and the inner current collector. The negative electrode bodies arranged in the stacking direction are electrically connected to the other current collector by contacting the other current collector as the other one of the outer current collector and the inner current collector.

2. The power storage element according to claim 1, wherein The electrode body is configured to stack the unit electrode layers by winding or folding the sheet-like electrode laminate in a manner that bends both end portions of the extension direction of the sheet-like electrode laminate.

3. The power storage element according to claim 1 or 2, wherein At least one of the positive electrode body and the negative electrode body that configures each unit electrode layer contacts both of a pair of facing walls arranged in the facing direction and is electrically connected to the corresponding current collector.

4. The power storage element according to claim 1 or 2, wherein The unit electrode layers of the electrode body have portions in which the dimension in the facing direction is formed to be the same length over a predetermined range of the extension direction.

5. The power storage element according to claim 1 or 2, wherein Each unit electrode layer of the electrode body is formed to have a rectangular shape having sides along the extension direction and the facing direction when viewed in the stacking direction.

6. The power storage element according to claim 1 or 2, wherein The electrode body is formed with a through hole that penetrates the electrode body in the stacking direction of the unit electrode layers and into which the inner facing wall is fitted, and the through hole is formed in a long hole shape extending in the extension direction.

7. The power storage element according to claim 6, wherein The length of the extension direction of the through hole is formed to be greater than the length of the extension direction of the inner facing wall.

8. The power storage element according to claim 1 or 2, wherein At least one of the outer facing wall and the inner facing wall is formed with a concave-convex structure that prevents displacement of the position of the contacted electrode body.

9. The power storage element according to claim 1 or 2, wherein At least one of the outer facing wall and the inner facing wall has a reinforcing structure that prevents deformation in the facing direction.

10. A power storage element module formed by connecting in series a plurality of the power storage element described in any one of claims 1 to 9, wherein The power storage element module has a connection current collector unit in which the outer current collector of one of the two power storage elements adjacent in the stacking direction and the inner current collector of the other power storage element are formed integrally, and the connection current collector unit has a connection structure that fits and connects the two power storage elements adjacent in the stacking direction.

11. An electrode body formed of a plurality of unit electrode layers comprising positive electrode bodies, negative electrode bodies, and separators sandwiched between the positive electrode bodies and the negative electrode bodies, and stacked in a predetermined stacking direction, wherein The electrode body is configured to connect the unit electrode layers adjacent in the stacking direction by bending end portions in an extension direction orthogonal to the stacking direction, and a portion of the electrode body other than the both end portions in the extension direction is a portion in which the plurality of unit electrode layers are stacked together. The electrode body is formed with a through hole that penetrates in the stacking direction, and the electrode body has an outer exposure surface exposed to the outside in a facing direction orthogonal to the extension direction and the stacking direction and electrically connected to a current collector, and an inner exposure surface opposite to the through hole and exposed to the inside in the facing direction and electrically connected to the current collector.

12. A method for manufacturing a power storage element, wherein The present application provides a method for manufacturing an electrode body, which includes: a sheet preparation step of preparing a sheet-shaped positive electrode body, a sheet-shaped negative electrode body, and two separators; a layering step of forming a sheet-shaped electrode layered body having a unit electrode layer in which one of the positive electrode body and the negative electrode body is layered between the two separators, and the other of the positive electrode body and the negative electrode body is layered outside one of the two separators; a winding step of forming an electrode body having a plurality of the unit electrode layers in a layering direction by winding the electrode layered body in an extending direction thereof; an exposed edge portion setting step of setting the positive electrode body and the negative electrode body to have positive electrode body exposed edge portions and negative electrode body exposed edge portions, respectively, which are exposed from the electrode body in an opposite direction orthogonal to the layering direction and the extending direction; a current collector preparation step of preparing an outside current collector having a pair of outside opposite walls facing each other at intervals, and an inside current collector having a pair of inside opposite walls facing each other at intervals inside the pair of outside opposite walls; and an assembled electrode body step of assembling the electrode body, the outside current collector, and the inside current collector such that the positive electrode body exposed edge portions contact either one of the pair of outside opposite walls and the pair of inside opposite walls, and the negative electrode body exposed edge portions contact the other one of the pair of outside opposite walls and the pair of inside opposite walls.

13. The manufacturing method of claim 12, wherein, The exposed edge portion setting step includes a processing step for exposure before the winding step, in which the positive electrode body, the negative electrode body, and the separators, or the electrode layered body are processed to form the positive electrode body exposed edge portions and the negative electrode body exposed edge portions.

14. The manufacturing method according to claim 13, wherein, The processing step for exposure includes a slit processing step in which a slit is formed in a thickness direction inside a width direction of the positive electrode body, the negative electrode body, and the separators, or the electrode layered body, the sheet preparation step includes a positive electrode coating step of coating a positive electrode active material on a positive electrode base, and a negative electrode coating step of coating a negative electrode active material on a negative electrode base, and the positive electrode coating step and the negative electrode coating step each include a step of continuously coating each active material in an extending direction in a slit outer region other than a slit region in which the slit is to be formed in the slit processing step.

15. The manufacturing method according to claim 14, wherein, The slit processing step is performed after the positive electrode coating step and the negative electrode coating step.

16. The manufacturing method according to claim 14 or 15, wherein, The slit processing step includes a step of forming the slit on each of the positive electrode body, the negative electrode body, and the separators in the sheet preparation step, and the sheet preparation step includes a step of forming a width direction dimension of the slit of one of the positive electrode body and the negative electrode body to be larger than a width direction dimension of the slit of the other, and forming the width direction dimension of the other to be larger than the width direction dimension of the one.

17. The manufacturing method according to any one of claims 12 to 15, wherein, The sheet preparation step includes a rolling step of rolling at least one of the positive electrode body and the negative electrode body, and the exposed edge portion setting step includes a step of setting the positive electrode exposed edge portion and / or the negative electrode exposed edge portion to extend in a direction orthogonal to the rolling direction in the positive electrode body and / or the negative electrode body after rolling.

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