Energy storage device and method for manufacturing an energy storage device

Abstract

To provide an energy storage device that suppresses the formation of wrinkles in the exterior body. [Solution] The energy storage device includes an energy storage module containing a plurality of electrodes stacked along a first direction; a first cover member having a first wall, a second wall, and a third wall; a second cover member having a fourth wall, a fifth wall, and a sixth wall; a first outer casing having a first recess formed by a first portion, a second portion, and a third portion; and a second outer casing having a second recess formed by a fourth portion, a fifth portion, and a sixth portion. The first cover member is fixed to the inner surface of the first outer casing with the first wall, second wall, and third wall in contact with the first portion, second portion, and third portion of the first outer casing. The second cover member is fixed to the inner surface of the second outer casing with the fourth wall, fifth wall, and sixth wall in contact with the fourth portion, fifth portion, and sixth portion of the second outer casing.

Description

Technical Field

[0001] The present disclosure relates to a power storage device and a method for manufacturing the power storage device.

Background Art

[0002] Patent Document 1 discloses a power storage device. This power storage device includes an electrode laminate in which a plurality of bipolar electrodes are laminated, and an exterior body that seals the electrode laminate. The exterior body seals a structural member together with the electrode laminate. The structural member sandwiches the electrode laminate in the planar direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an inclusion such as an electrode laminate is accommodated in a recess of an exterior body having a recess and vacuum - sealed, if a gap is formed between the exterior body and the inclusion before decompression, wrinkles may be formed on the exterior body after vacuum - sealing. When wrinkles are formed on the exterior body, there is a risk that the exterior body will be damaged by thermal shock. In particular, when the inclusion is a three - dimensional object such as a rectangular parallelepiped shape, a gap is formed between the corner of the inclusion formed between the mutually intersecting side surfaces and the recess of the exterior body, and thus wrinkles are likely to be formed on the exterior body covering the corner after vacuum - sealing.

[0005] The present disclosure provides a power storage device that suppresses the formation of wrinkles in the exterior body.

Means for Solving the Problems

[0006] An energy storage device relating to one aspect of the present disclosure comprises an energy storage module, a first cover member, a second cover member, a first outer casing, and a second outer casing. The energy storage module includes a plurality of electrodes stacked along a first direction. The energy storage module has a first surface intersecting in the first direction, a second surface continuous with the first surface and intersecting in a second direction intersecting in the first direction, and a third surface continuous with the first and second surfaces and intersecting in a third direction intersecting in the first and second directions. The first cover member has a first wall intersecting in the first direction, a second wall continuous with the first wall and intersecting in the second direction, and a third wall continuous with the first and second walls and intersecting in a third direction. The first cover member is arranged to cover one side of the second surface of the energy storage module in the first direction when viewed from the second direction. The second cover member has a fourth wall intersecting in the first direction, a fifth wall continuous with the fourth wall and intersecting in the second direction, and a sixth wall continuous with the fourth and fifth walls and intersecting in the third direction. The second cover member is positioned to cover the other side of the second surface of the energy storage module in the first direction when viewed from the second direction. The first outer casing has a first recess formed by a first portion intersecting in the first direction, a second portion continuous with the first portion and intersecting in the second direction, and a third portion continuous with the first and second portions and intersecting in the third direction. The first outer casing houses the energy storage module and one side of the cover member in the first direction within the first recess. The second outer casing has a second recess formed by a fourth portion intersecting in the first direction, a fifth portion continuous with the fourth portion and intersecting in the second direction, and a sixth portion continuous with the fourth and fifth portions and intersecting in the third direction. The second outer casing houses the energy storage module and the other side of the cover member in the first direction within the second recess. The first cover member is fixed to the inner surface of the first outer casing with its first, second, and third walls in contact with the first, second, and third portions of the first outer casing, respectively. The second cover member is fixed to the inner surface of the second outer casing with its fourth, fifth, and sixth walls in contact with the fourth, fifth, and sixth portions of the second outer casing, respectively.

[0007] In the above-described energy storage device, the first cover member is fixed to the first outer casing with the first cover member in contact with all of the first, second, and third parts that extend in directions intersecting each other in the recess. Furthermore, the second cover member is fixed to the second outer casing pack with the second cover member in contact with all of the fourth, fifth, and sixth parts that extend in directions intersecting each other in the recess. As a result, misalignment of the corners of the first cover member (for example, the connection between the first wall and the second wall, the connection between the first wall and the third wall, and the connection between the second wall and the third wall) relative to the corners of the recess (for example, the connection between the first and second parts, the connection between the first and third parts, and the connection between the second and third parts) is suppressed, and the formation of wrinkles in the corners of the recess is suppressed.

[0008] In one example, the first, second, and third walls of the first cover member are connected to each other with an R-shape. The first, second, and third parts of the first exterior body are connected to each other with an R-shape.

[0009] In one example, the curvature of the connection portions between the first, second, and third walls of the first cover member is equal to the curvature of the connection portions between the first, second, and third parts of the first exterior body.

[0010] The first exterior may include a conductive member that constitutes the center of the first part, and a sealing member connected to the outer edge of the conductive member that constitutes the periphery of the first part and the second and third parts. The first cover member is fixed to the inner surface of the first exterior by being compatible with the sealing member.

[0011] The first cover member and the second cover member are positioned facing each other in a first direction and are in partial contact with each other.

[0012] A method for manufacturing an energy storage device according to one aspect of the present disclosure includes the steps of: preparing an energy storage module, a first cover member, a second cover member, a first outer casing, and a second outer casing; fixing the first cover member in a first recess of the first outer casing such that the first, second, and third walls of the first cover member abut against the first, second, and third portions of the first outer casing, respectively; fixing the second cover member in a second recess of the second outer casing such that the fourth, fifth, and sixth walls of the second cover member abut against the fourth, fifth, and sixth portions of the second outer casing, respectively; housing one side of the energy storage module in a first direction within the first recess of the first outer casing in which the first cover member is fixed; stacking the second outer casing on the first outer casing such that the other side of the energy storage module in a first direction, which is housed in the first recess, is housed in the second recess; and welding the first flange portion of the first outer casing and the second flange portion of the second outer casing to each other. [Effects of the Invention]

[0013] According to this disclosure, it is possible to provide an energy storage device that suppresses the formation of wrinkles in the exterior body. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic plan view showing an example of an energy storage device. [Figure 2] Figure 2 is a schematic diagram showing one side view of an energy storage module that constitutes an example of an energy storage device. [Figure 3] Figure 3 is a cross-sectional view along the line III-III in Figure 2. [Figure 4] Figure 4 is a cross-sectional view along the line IV-IV in Figure 1. [Figure 5] Figure 5 is a cross-sectional view along the VV line in Figure 1. [Figure 6] Figure 6 is a cross-sectional view along the line VI-VI in Figure 1. [Figure 7] Figure 7 is a perspective view showing an example of a cover component. [Figure 8] Figure 8 is a perspective view showing an example of a cover component. [Figure 9]FIG. 9 is a perspective view showing a cover member of an example. [Figure 10] FIG. 10 is a perspective view showing a cover member of an example. [Figure 11] FIG. 11 is a flowchart showing a manufacturing process of an example of a power storage device. [Figure 12] FIG. 12 is a cross-sectional view schematically showing another example of a power storage device. [Figure 13] FIG. 13 is a cross-sectional view schematically showing yet another example of a power storage device.

MODE FOR CARRYING OUT THE INVENTION

[0015] Hereinafter, an embodiment will be described with reference to the drawings. In the description of the drawings, the same or equivalent elements may be denoted by the same reference numerals, and redundant descriptions may be omitted. Also, in the description, an orthogonal coordinate system defined by the X-axis, Y-axis, and Z-axis shown in the drawings may be referred to.

[0016] FIG. 1 is a schematic plan view showing a power storage device according to this embodiment. The power storage device 1 can be used, for example, as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage device 1 is, for example, a secondary battery such as a nickel-metal hydride secondary battery or a lithium-ion secondary battery. The power storage device 1 may be an electric double layer capacitor or an all-solid-state battery. Here, the case where the power storage device 1 is a lithium-ion secondary battery is shown.

[0017] The energy storage device 1 comprises an energy storage module 1A, a cover member 100, a connector unit 30, and an outer packaging pack 90. ​​The energy storage module 1A has a rectangular shape when viewed from the Z-axis direction (first direction) and has four outer surfaces 20s that extend in the Z-axis direction. That is, the energy storage module 1A has a roughly rectangular parallelepiped shape and has an upper surface 10a (first surface) and a lower surface 10b (first surface) that intersect in the Z-axis direction, outer surfaces 20sA and 20sB (second surfaces) that intersect in the Y-axis direction (second direction), and outer surfaces 20sC and 20sD (third surfaces) that intersect in the X-axis direction (third direction). The upper surface 10a and the lower surface 10b face each other in the Z-axis direction, outer surfaces 20sA and 20sB face each other in the Y-axis direction, and outer surfaces 20sC and 20sD face each other in the X-axis direction. The upper surface 10a and the lower surface 10b have a positive terminal electrode 12 and a negative terminal electrode 13, respectively, as will be described later, and are used for power extraction.

[0018] One example of a cover member 100 is composed of a cover member 101, a cover member 102, and a cover member 103. Cover members 101 and 102 are arranged to cover the outer surface 20sA when viewed from the Y-axis direction. Cover member 103 is arranged to cover the outer surface 20sB when viewed from the Y-axis direction. The connector unit 30 is positioned between cover member 101 and cover member 102 in the X-axis direction.

[0019] Figure 2 is a schematic diagram showing one outer surface 20sA of the energy storage module 1A. Figure 3 is a schematic cross-sectional view of an example of the energy storage module 1A, showing a cross-section along the line III-III in Figure 2. The outer surface 20sA of the energy storage module 1A includes a region R1 on which an additional member 50, described later, is provided, and regions R2 and R3 adjacent to region R1. In the example shown in Figure 2, region R2 is located on the negative side in the X-axis direction compared to region R1, and region R3 is located on the positive side in the X-axis direction compared to region R1. The additional member includes an injection port 53A used when injecting electrolyte into the energy storage module 1A.

[0020] As shown in Figure 3, the energy storage module 1A includes an electrode stack 10 and a sealing body 29 that surrounds the electrode stack 10 when viewed from the Z-axis direction. The electrode stack 10 includes a plurality of electrodes stacked along the Z-axis direction. The Z-axis direction is the direction in which the electrodes are stacked and is the height direction of the energy storage device 1. The plurality of electrodes include a plurality of bipolar electrodes 11, a positive terminal electrode 12, and a negative terminal electrode 13. Separators 14 are interposed between adjacent electrodes. The positive terminal electrode 12 constitutes part of the upper surface 10a of the energy storage module 1A, and the negative terminal electrode 13 constitutes part of the lower surface 10b of the energy storage module 1A.

[0021] The bipolar electrode 11 comprises a current collector 15, a positive electrode active material layer 16, and a negative electrode active material layer 17. The current collector 15 is rectangular in shape when viewed from the Z-axis direction and is in the form of a sheet. The active material layers (positive electrode active material layer 16, negative electrode active material layer 17) are located in the center of the current collector 15 when viewed from the Z-axis direction and are not located on the peripheral edge 15c of the current collector 15. The positive electrode active material layer 16 is located on the first surface 15a of the current collector 15. The negative electrode active material layer 17 is located on the second surface 15b of the current collector 15. The first surface 15a of the current collector 15 faces the other side in the Z-axis direction (the side where the negative electrode terminal electrode 13 is located in Figure 3), and the second surface 15b of the current collector 15 faces the one side in the Z-axis direction (the side where the positive electrode terminal electrode 12 is located in Figure 3). Multiple bipolar electrodes 11 are stacked such that the positive electrode active material layer 16 of one adjacent bipolar electrode 11 and the negative electrode active material layer 17 of the other bipolar electrode 11 face each other in the stacking direction.

[0022] The positive terminal electrode 12 comprises a current collector 15 and a positive electrode active material layer 16 provided on the first surface 15a of the current collector 15. The second surface 15b of the current collector 15 of the positive terminal electrode 12 does not have an active material layer. The positive terminal electrode 12 is laminated on the bipolar electrode 11 at one end of the electrode stack 10 in the Z-axis direction. The positive terminal electrode 12 is laminated on the bipolar electrode 11 such that its positive electrode active material layer 16 faces the negative electrode active material layer 17 of the bipolar electrode 11.

[0023] The negative electrode terminal electrode 13 comprises a current collector 15 and a negative electrode active material layer 17 provided on the second surface 15b of the current collector 15. The first surface 15a of the current collector 15 of the negative electrode terminal electrode 13 does not have an active material layer. The negative electrode terminal electrode 13 is laminated on the bipolar electrode 11 at the end of the electrode laminate 10 in the Z-axis direction, opposite to the side on which the positive electrode terminal electrode 12 is provided. The negative electrode terminal electrode 13 is laminated on the bipolar electrode 11 such that its negative electrode active material layer 17 faces the positive electrode active material layer 16 of the bipolar electrode 11. In this embodiment, the current collectors of the bipolar electrode 11, positive electrode terminal electrode 12, and negative electrode terminal electrode 13 are all denoted by the same reference numeral as current collector 15, but the current collectors of the bipolar electrode 11, positive electrode terminal electrode 12, and negative electrode terminal electrode 13 may be the same as or different from each other.

[0024] The separator 14 is positioned between adjacent bipolar electrodes 11, between the positive terminal electrode 12 and the bipolar electrode 11, and between the negative terminal electrode 13 and the bipolar electrode 11. The separator 14 is interposed between the positive electrode active material layer 16 and the negative electrode active material layer 17, separating them. The separator 14 prevents short circuits caused by contact between adjacent electrodes while allowing charge carriers such as lithium ions to pass through.

[0025] The current collector 15 is a chemically inert electrical conductor that allows current to continue flowing through the positive electrode active material layer 16 and the negative electrode active material layer 17 during the discharge or charging of the lithium-ion secondary battery. The material of the current collector 15 is, for example, a metal material, a conductive resin material, or a conductive inorganic material. Examples of conductive resin materials include conductive polymer materials or resins to which conductive fillers are optionally added to non-conductive polymer materials. The current collector 15 may comprise multiple layers. In this case, each layer of the current collector 15 may contain the above-mentioned metal material or conductive resin material.

[0026] A coating layer may be formed on the surface of the current collector 15. This coating layer may be formed by known methods such as plating or spray coating. The current collector 15 may be in the form of a plate, foil (e.g., metal foil), film, or mesh. Examples of metal foils include aluminum foil, copper foil, nickel foil, titanium foil, or stainless steel foil. The current collector 15 may be an alloy foil or clad foil of the above metals. If the current collector 15 is in the form of a foil, its thickness may be, for example, 1 μm to 100 μm. In this embodiment, the current collector 15 is a foil in which aluminum foil and copper foil are integrated, or aluminum foil.

[0027] The positive electrode active material layer 16 contains a positive electrode active material capable of intercalating and releasing charge carriers such as lithium ions. Examples of positive electrode active materials include lithium composite metal oxides having a layered rock salt structure, metal oxides having a spinel structure, and polyanionic compounds. The positive electrode active material can be any material suitable for use in lithium-ion secondary batteries. The positive electrode active material layer 16 may contain multiple positive electrode active materials. In this embodiment, the positive electrode active material layer 16 contains olivine-type lithium iron phosphate (LiFePO4) as a composite oxide.

[0028] The negative electrode active material layer 17 contains a negative electrode active material capable of intercalating and releasing charge carriers such as lithium ions. The negative electrode active material may be an element, an alloy, or a compound. Examples of negative electrode active materials include Li, carbon, and metal compounds. The negative electrode active material may also be an element or compound thereof that can be alloyed with lithium. Examples of carbon include natural graphite, artificial graphite, hard carbon (carbon that is difficult to graphitize), or soft carbon (carbon that is easily graphitized). Examples of artificial graphite include highly oriented graphite and mesocarbon microbeads. Examples of elements that can be alloyed with lithium include silicon or tin. In this embodiment, the negative electrode active material layer 17 contains graphite as a carbon-based material.

[0029] Each of the positive electrode active material layer 16 and the negative electrode active material layer 17 (hereinafter sometimes simply referred to as the "active material layer") may further contain, as necessary, conductive additives, binders, electrolytes (polymer matrix, ion-conducting polymer, electrolyte solution, etc.), electrolyte-supporting salts (lithium salts) to enhance ionic conductivity, etc. Conductive additives are added to enhance the conductivity of each electrode (bipolar electrode 11, positive electrode terminal electrode 12, negative electrode terminal electrode 13). Examples of conductive additives include acetylene black, carbon black, or graphite.

[0030] Examples of binders include fluororesins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluororubber; thermoplastic resins such as polypropylene and polyethylene; imide resins such as polyimide and polyamideimide; alkoxysilyl group-containing resins; acrylic resins such as acrylic acid or methacrylic acid; styrene-butadiene rubber (SBR); alginates such as carboxymethylcellulose, sodium alginate, and ammonium alginate; water-soluble cellulose ester crosslinked polymers; and starch-acrylic acid graft polymers. These binders can be used individually or in combination. Examples of solvents include water and N-methyl-2-pyrrolidone (NMP).

[0031] The separator 14 may be, for example, a porous sheet or nonwoven fabric containing a polymer that absorbs and retains electrolytes. Examples of materials for the separator 14 include polypropylene, polyethylene, polyolefin, and polyester. The separator 14 may have a single-layer structure or a multilayer structure. The multilayer structure may include, for example, a ceramic layer as an adhesive layer or a heat-resistant layer. The separator 14 may be impregnated with an electrolyte. The separator 14 may be composed of an electrolyte such as a polymer electrolyte or an inorganic electrolyte. Examples of electrolytes impregnated into the separator 14 include a liquid electrolyte (electrolyte solution) containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent, or a polymer gel electrolyte containing an electrolyte held in a polymer matrix.

[0032] When the separator 14 is impregnated with an electrolyte, known lithium salts such as LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, and LiN(CF3SO2)2 may be used as the electrolyte salt. Furthermore, known solvents such as cyclic carbonates, cyclic esters, linear carbonates, linear esters, and ethers may be used as the non-aqueous solvent. Two or more of these known solvent materials may be used in combination.

[0033] The sealing body 29 includes a sealing main body 20 and an additional member 50. The sealing main body 20 is formed in a frame shape on the periphery of the electrode stack 10 so as to surround the periphery of the electrode stack 10 when viewed from the Z-axis direction. The sealing main body 20 can be joined to the first surface 15a and the second surface 15b of each current collector 15 at the peripheral edge 15c of each current collector 15. The sealing main body 20 can form an internal space S between adjacent current collectors 15 in the Z-axis direction and can seal each of these internal spaces S. In this embodiment, each internal space S contains an electrolyte (not shown). That is, the sealing main body 20 cooperates with adjacent current collectors 15 in the Z-axis direction to define the internal space S in which the electrolyte is contained. The sealing main body 20 can prevent the electrolyte contained in the internal space S from flowing out to the outside.

[0034] The sealing body portion 20 can suppress the intrusion and discharge of air, moisture, etc., between the outside and the internal space S of the electrode stack 10. The sealing body portion 20 can, for example, suppress the leakage of gas generated at each electrode due to charge-discharge reactions, etc., to the outside of the energy storage module 1A. The edges of the separator 14 are joined to the sealing body portion 20. The sealing body portion 20 contains an insulating material. Examples of materials for the sealing body portion 20 include various resin materials such as polypropylene, polyethylene, polystyrene, ABS resin, acid-modified polypropylene, acid-modified polyethylene, and acrylonitrile styrene resin.

[0035] An example of a sealing body 20 includes a plurality of sealing materials 21, a pair of end sealing materials 24, and a plurality of spacers 22. The sealing materials 21, end sealing materials 24, and spacers 22 may be frame-shaped members formed in a sheet-like manner. The sealing body 20 also has a welded end 23. The sealing material 21 is frame-shaped when viewed from the Z-axis direction and is provided along the peripheral edge 15c of the current collector 15. The sealing material 21 is provided so as to extend from the first surface 15a of the current collector 15 through the end surface to the second surface 15b, covering the peripheral edge 15c. That is, the sealing material 21 has an inner portion that overlaps the current collector 15 and an outer portion that is located outside the edge of the current collector 15 when viewed from the Z direction on the first surface 15a and the second surface 15b of the current collector 15, and the outer portions of a pair of adjacent sealing materials 21 on either side of the current collector 15 are connected. The sealing material 21 can be welded to at least one of the first surface 15a and the second surface 15b of the current collector 15. In this embodiment, the sealing material 21 is welded to both the first surface 15a and the second surface 15b of the current collector 15.

[0036] The end seal material 24 has a frame shape when viewed from the Z-axis direction and is provided along the peripheral edge 15c of the current collector 15 that constitutes the positive terminal electrode 12 and the negative terminal electrode 13, respectively. Therefore, the end seal material 24 is arranged to sandwich the multiple seal materials 21 from the Z-axis direction. The end seal material 24 can be welded to at least one of the first surface 15a and the second surface 15b of the current collector 15. In this embodiment, the end seal material 24 is welded to both the first surface 15a and the second surface 15b of the current collector 15.

[0037] The spacer 22 has a frame shape when viewed from the Z-axis direction and is positioned along the peripheral edge 15c of the current collector 15. The spacer 22 is positioned to be interposed between adjacent sealing materials 21 in the Z-axis direction. Furthermore, the spacer 22 is positioned to be interposed between adjacent sealing materials 21 and end sealing materials 24 in the Z-axis direction. The spacer 22 can maintain the distance between adjacent current collectors 15 in the Z-axis direction. That is, the spacer 22, sealing materials 21 and end sealing materials 24 define an internal space S between adjacent current collectors 15.

[0038] The welded end 23 is formed by welding together the ends of the multiple sealing materials 21, the pair of end sealing materials 24, and the multiple spacers 22 that are opposite to the internal space S, thereby integrating them. When viewed from the Z-axis direction, the welded end 23 has a frame-like shape that surrounds the electrode stack 10. The side of the welded end 23 opposite to the internal space S extends along the Z-axis direction and constitutes the outer surface 20s of the sealing body portion 20. In other words, the sealing body portion 20 includes the outer surface 20s opposite to the internal space S. The outer surface 20s may be formed as a flat surface.

[0039] The sealing body portion 20 has a plurality of communication holes 27 that communicate with each of the plurality of internal spaces S. For example, the communication holes 27 are notched portions formed in the spacer 22 and are formed to penetrate the welded end portion 23. The communication holes 27 have one opening in the internal space S and the other opening in the outer surface 20s of the sealing body portion 20. In the illustrated example, the opening is formed in the outer surface 20sA.

[0040] The additional member 50 is formed to overlap the region R1 on the outer surface 20sA where the communication holes 27 are formed. By being molded into a predetermined shape, the additional member 50 provides a liquid injection port portion 53A having a plurality of liquid injection ports that communicate with each of the plurality of communication holes 27. The additional member 50 is joined to the welded end portion 23. For example, the additional member 50 is integrally joined to the welded end portion 23 by injection molding. An example of the additional member 50 includes a main body portion 51, a first overhang portion 55, and a second overhang portion 57.

[0041] The main body 51 partially covers the outer surface 20sA. For example, the main body 51 covers the outer surface 20sA such that it includes a region R1 in which multiple communication holes 27 are formed. As described above, each of the multiple communication holes 27 communicates with a plurality of internal spaces S. In the example shown in Figure 2, 30 communication holes 27 corresponding to 30 layers of internal space formed between each current collector 15 are arranged discretely in the X-axis and Z-axis directions. More specifically, the communication holes 27 corresponding to the 1st to 10th layers of internal space are arranged evenly spaced along the X-axis, with the positive terminal electrode 12 side as the base end, while the communication holes 27 corresponding to the 11th to 20th layers of internal space, and the communication holes 27 corresponding to the 21st to 30th layers of internal space are arranged sequentially in the Z-axis direction below the 1st to 10th layers of internal space. The main body 51 extends in a rectangular shape along the X-axis and Z-axis directions in order to cover the region R1 in which these 30 communication holes 27 are formed.

[0042] The main body portion 51 is formed in the shape of a rectangular plate with a predetermined thickness in the Y-axis direction. The main body portion 51 has openings 52 at positions corresponding to the communication holes 27. The main body portion 51 also has protruding frame portions 53 that project in the Y-axis direction, intersecting (orthogonal to) the outer surface 20sA. When viewed from the Y-axis direction, the protruding frame portions 53 surround each opening 52 and function as partition walls separating each opening 52. In the example in Figure 2, ten protruding frame portions 53 are arranged in the X-axis direction, each having three spaces to separate three vertically aligned openings 52.

[0043] The protruding frame portion 53 is used, for example, when injecting electrolyte into each of the internal spaces S. For example, when injecting electrolyte, the nozzle of the injection device is brought into close contact with the top surface of the protruding frame portion 53, and the electrolyte is introduced into the space of each protruding frame portion 53 from the nozzle. This makes it possible to inject electrolyte into the internal space S from the opening 52 and the communication hole 27. After the electrolyte is injected, a laminate sheet 54 may be provided on the protruding frame portion 53 to seal it. The laminate sheet 54 may be, for example, a sheet in which a metal layer such as aluminum is covered with a resin layer. The laminate sheet 54 may be fused to, for example, the top surface of the protruding frame portion 53.

[0044] In one example, the main body 51 includes a terminal section 58 for voltage detection (see Figure 2). The terminal section 58 is formed in the main body 51 at a position offset to the positive side in the X-axis direction from the liquid injection port section 53A, which is composed of a plurality of protruding frame sections 53. For example, the terminal section 58 is provided adjacent to a protruding frame section 53 formed at the positive end in the X-axis direction, via a flat surface 51a. In one example, the terminal section 58 is provided at the positive end in the X-axis direction of the main body 51. The terminal section 58 provides a plurality of terminals 58a that are electrically connected to a plurality of current collectors 15. One end of each terminal 58a is connected to the corresponding current collector 15, and the other end of each terminal 58a is exposed from the main body 51. The terminals 58a only need to be electrically connected to the current collectors 15, and may be, for example, metal pins. A connector unit 30 (see Figure 1) is fixed to the terminal section 58. One example of a connector unit 30 includes a housing 31 having multiple contacts connected to multiple terminals 58a, and a connector 33 connected to the housing 31. A flexible circuit board may be connected to the connector 33, which is pulled out to the outside of the outer packaging pack 90.

[0045] The first overhang portion 55 and the second overhang portion 57 are formed by connecting to both ends of the main body portion 51 in the Z-axis direction. The first overhang portion 55 partially covers one end of the welded end portion 23 in the Z-axis direction (the positive Z-axis side). For example, the first overhang portion 55 partially covers the end seal material 24 joined to the positive electrode terminal 12. In the illustrated example, the end edge 55a of the first overhang portion 55 extends from the end edge of the welded end portion 23 to a position outside the inner edge 22a of the spacer 22 and the inner edge 21a of the seal material 21 when viewed from the Z-axis direction, but this is not limited to this. The first overhang portion 55 may be formed in the shape of a rectangular plate having the same length as the main body portion 51 in the X-axis direction. Similarly to the first overhang portion 55, the second overhang portion 57 partially covers the other end of the welded end portion 23 in the Z-axis direction (the negative Z-axis side). The position of the edge 57a of the second overhang portion 57 in the Y-axis direction coincides with the edge 55a of the first overhang portion 55.

[0046] Figure 4 is a cross-sectional view along line IV-IV in Figure 1. Figure 5 is a cross-sectional view along line VV in Figure 1. Figure 6 is a cross-sectional view along line VI-VI in Figure 1. Note that in Figures 4 to 6, the energy storage module 1A included in the energy storage device 1 is depicted in a simplified manner. An example of an outer pack 90 (outer body) includes a first outer pack 90A (first outer body) and a second outer pack 90B (second outer body) arranged to face each other in the vertical direction. The first outer pack 90A has a recess 94A (first recess). The recess 94A is formed by a first portion 91A that extends in the Y-axis direction (more specifically in the XY plane) and intersects in the Z-axis direction, and a second portion 92A and a third portion 93A that are continuous with the first portion 91A and extend in the Z-axis direction. The second portion 92A intersects in the Y-axis direction, and the third portion 93A intersects in the X-axis direction. The second portion 92A and the third portion 93A are continuous with each other. The second portion 92A and the third portion 93A have a flange portion 94Aa (first flange portion) extending outward at the edge opposite to the connection portion with the first portion 91A. The recess 94A provides space for housing the energy storage module 1A, the cover member 100, and the connector unit 30.

[0047] The first outer packaging 90A includes a conductive member 95A and an outer film 96A (sealing member). The conductive member 95A has a rectangular shape in plan view and constitutes the center of the first portion 91A. The conductive member 95A abuts against the second surface 15b of the current collector 15 of the positive terminal electrode 12 and is electrically connected to the positive terminal electrode 12. The conductive member 95A may be, for example, a metal foil, and one example may be aluminum foil. The planar size of the conductive member 95A may be the same as or smaller than that of the current collector 15.

[0048] The outer film 96A constitutes the periphery of the first portion 91A, the second portion 92A, and the third portion 93A. The outer film 96A is configured to surround the outer periphery of the contents (in this case, the energy storage module 1A, the cover member 100, and the connector unit 30) when viewed from the Z-axis direction. The outer film 96A is connected to the periphery of the conductive member 95A. The outer film 96A has a rectangular frame shape. For example, the outer film 96A may be formed by welding together four strip-shaped sheet members along each of the four sides that make up the rectangle.

[0049] The outer film 96A is processed (e.g., by press forming) so that its outer edge is located closer to the outer film 96B than its inner edge. This processing creates a recess 94A in the outer film 96A that opens toward the outer film 96B. The inner edge of the outer film 96A, which forms a rectangular frame shape when viewed from the Z-axis direction, is located inside the periphery of the conductive member 95A. The inner edge of the outer film 96A and the periphery of the conductive member 95A are joined together in an overlapping manner. In one example, the inner edge of the outer film 96A and the periphery of the conductive member 95A may be joined together by a resin material 97A. The resin material 97 may be a rectangular frame-shaped sealing resin formed in a sheet. For example, the inner edge of the rectangular frame-shaped resin material 97 may be located inside the inner edge of the outer film 96A, and the outer edge of the resin material 97 may coincide with the periphery of the conductive member 95A. The outer edge of the outer film 96A is located outside the periphery of the contents when viewed from the Z-axis direction.

[0050] The outer film 96A may be, for example, a laminate film containing a metal layer. That is, the outer film 96A may be a sheet-like member in which both sides of a metal layer 96a, such as aluminum, are covered with resin layers 96b and 96c.

[0051] The second outer packaging 90B has the same configuration as the first outer packaging 90A. That is, the second outer packaging 90B has a conductive member 95B corresponding to the conductive member 95A and an outer film 96B corresponding to the outer film 96A. The conductive member 95B abuts against the first surface 15a of the current collector 15 of the negative terminal electrode 13 and is electrically connected to the negative terminal electrode 13. The outer film 96B has the same shape as the outer film 96A and is arranged to face the outer film 96A. That is, the outer film 96B has a recess 94B (second recess) that opens toward the outer film 96A.

[0052] The recess 94B is formed by a fourth portion 91B intersecting in the Z-axis direction, a fifth portion 92B that is continuous with the fourth portion 91B and intersects in the Y-axis direction, and a sixth portion 93B that is continuous with the fourth portion 91B and the fifth portion 92B and intersects in the X-axis direction. The fifth portion 92B and the sixth portion 93B have a flange portion 94Ba (second flange portion) that extends outward at the edge opposite to the connection portion with the fourth portion 91B. Similar to the recess 94A, the recess 94B provides space for housing the energy storage module 1A, the cover member 100, and the connector unit 30.

[0053] The outer edges of outer film 96A and outer film 96B are joined to each other. For example, the flange portion 94Aa formed by outer film 96A and the flange portion 94Ba formed by outer film 96B may be welded to each other. By sealing the outer edges of outer film 96A and outer film 96B to each other, a sealed space is formed inside the outer pack 90. ​​After the energy storage module 1A, etc., is housed in the outer pack 90, the outer pack 90 may be sealed under reduced pressure. In the following description, when conductive members 95A and 95B are not distinguished, they are collectively referred to as conductive member 95. Also, when outer film 96A and outer film 96B are not distinguished, they are collectively referred to as outer film 96.

[0054] Next, the cover member 100 will be described. The cover member 100 is housed in the outer pack 90 together with the energy storage module 1A and the connector unit 30, positioned between the outer surface 20s of the energy storage module 1A and the outer film 96. The cover member 100 is positioned to cover the outer surface 20s of the energy storage module 1A when viewed from the Y-axis direction. A gap may be formed between the cover member 100 and the outer surface 20s in the Y-axis direction.

[0055] In one example of a power storage device 1, the cover member 100 is composed of cover member 101 and cover member 102 (see Figures 1 and 5) which are positioned between the outer surface 20sA of the power storage module 1A and the outer film 96, and cover member 103 (see Figures 1 and 6) which is positioned between the outer surface 20sB of the power storage module 1A and the outer film 96. Cover member 101 is positioned on the positive side in the X-axis direction relative to the connector unit 30. Cover member 102 is positioned on the negative side in the X-axis direction relative to the connector unit 30.

[0056] The cover member 101 includes a first cover member 110 and a second cover member 120 arranged adjacent to each other in the Z-axis direction. The first cover member 110 is fixed to the outer film 96A (first outer pack 90A), and the second cover member 120 is fixed to the outer film 96B (second outer pack 90B). Figures 7 and 8 are perspective views showing the first cover member 110. Figure 9 is a perspective view showing the second cover member 120.

[0057] The first cover member 110 includes a base wall 111 (first wall) extending along the Y-axis direction (more specifically, the XY plane), and side walls 112 (second wall) and 113 projecting toward the second cover member 120 from both ends of the base wall 111 in the Y-axis direction. The outer surface 111b of the base wall 111 faces the first portion 91A of the first outer packaging 90A, and the outer surface 112b of the side wall 112 faces the second portion 92A of the first outer packaging 90A. The first cover member 110 also has side walls 114 and 115 extending toward the second cover member 120 from both ends of the base wall 111 in the X-axis direction. The base wall 111 intersects in the Z-axis direction, the side walls 112 and 113 intersect in the Y-axis direction, and the side walls 114 (third wall) and 115 intersect in the X-axis direction. The outer surface 114b of the side wall 114 faces the third portion 93 of the first outer packaging 90A.

[0058] In the illustrated example, the base wall 111 has a notched portion 111c formed at the edge where the side wall 115 is formed, for positioning the connector unit 30. As a result, the connection portion between the side wall 112 and the side wall 115 is formed in an inward corner shape. Therefore, the side wall 115 is divided in two in the center in the Y-axis direction. Also, the side wall 112 is divided in two in the X-axis direction at a position close to the side wall 115.

[0059] In one example, the connection portion 118a between the base wall 111 and the side wall 112, and the connection portion 118b between the base wall 111 and the side wall 114, are curved with a predetermined curvature. Furthermore, the connection portion 118c between the side wall 112 and the side wall 114 is curved with an even greater curvature. That is, these connection portions 118a, 118b, and 118c are formed in an R-shape with chamfered corners.

[0060] The base wall 111 of the first cover member 110 has an inner surface 111a that extends in the Y-axis direction (more specifically, the XY plane) and faces toward the second cover member 120. The first cover member 110 has a plurality of ribs 117 erected on the inner surface 111a. The ribs 117 are plate-shaped and extend along the YZ plane and are connected to the base wall 111, side wall 112, and side wall 113. The height of the ribs 117 in the Z-axis direction may be the same as that of the side walls 112, 113, 114, and 115. The plurality of ribs 117 are spaced apart from each other in the X-axis direction. The plurality of ribs 117 may be spaced equally apart in the X-axis direction or at different intervals.

[0061] As shown in Figure 8, a welding plate 108 is fixed to the outer surface 111b of an example base wall 111. In the illustrated example, a rectangular recess 111d is formed on the outer surface 111b of the base wall 111 in plan view. The welding plate 108 is plate-shaped with the same planar shape as the recess 111d and is placed inside the recess 111d. For example, the welding plate 108 and the recess 111d may be fixed to each other by the fitting of a projection 108a provided on the welding plate 108 and a hole 111e provided on the recess 111d. When the welding plate 108 is fixed to the recess 111d, the outer surface of the base wall 111 and the surface of the welding plate 108 may be flush. The welding plate 108 is the part that is welded to the outer film 96A of the first outer packaging pack 90A and is made of the same material (e.g., polypropylene) as the resin layer 96b of the outer packaging film 96A. Furthermore, if the first cover member 110 is formed of the same material as the resin layer 96b, the first cover member 110 does not need to have a welding plate 108.

[0062] The welding plate 108 of the first cover member 110 is welded to the opposing outer film 96A with the outer surface 111b of the base wall 111 in contact with the outer film 96A constituting the first part 91A of the first outer pack 90A, and the outer surface 112b of the side wall 112 in contact with the outer film 96A constituting the second part 92A of the first outer pack 90A. In this case, the outer surface 114b of the side wall 114 may be in contact with the third part 93A of the first outer pack 90A. When the base wall 111, side wall 112 and side wall 114 are in contact with the inner surface of the opposing recess 94A, the connection portion 118a between the base wall 111 and the side wall 112 may be in contact with the connection portion between the first part 91A and the second part 92A on the inner surface of the recess 94A. Similarly, the connection portion 118b between the base wall 111 and the side wall 114 may abut against the connection portion between the first portion 91A and the third portion 93A on the inner surface of the recess 94A. The connection portion 118c between the side wall 112 and the side wall 114 may abut against the connection portion between the second portion 92A and the third portion 93A on the inner surface of the recess 94A. That is, the connection portion 118a between the base wall 111 and the side wall 112 and the connection portion between the first portion 91A and the second portion 92A may have equal curvature. The connection portion 118b between the base wall 111 and the side wall 114 and the connection portion between the first portion 91A and the third portion 93A may have equal curvature. The connection portion 118c between the side wall 112 and the side wall 114 and the connection portion between the second portion 92A and the third portion 93A may have equal curvature.

[0063] The second cover member 120 has the same basic structure as the first cover member 110. The second cover member 120 has a base wall 121 (fourth wall), a side wall 122 (fifth wall), a side wall 123, a side wall 124 (sixth wall), and a side wall 125. The base wall 121 of the second cover member 120 corresponds to the base wall 111 of the first cover member 110 and extends along the Y-axis direction (more specifically, the XY plane) so as to face the base wall 111. A welding plate 108 is provided on the outer surface of the base wall 121, similar to the first cover member 110. When viewed from the Z-axis direction, the base wall 111 of the first cover member 110 and the base wall 121 of the second cover member 120 have the same shape. The side walls 122, 123, 124, and 125 of the second cover member 120 face the side walls 112, 113, 114, and 115 of the first cover member 110 in the Z-axis direction, and protrude toward the first cover member 110 from the edge of the base wall 121. The second cover member 120 also has a plurality of ribs 127. The ribs 127 correspond to the ribs 117 and face the ribs 117 of the first cover member 110 in the Z-axis direction.

[0064] Similar to the first cover member 110, the second cover member 120 is fixed to the second outer pack 90B by welding a welding plate 108 provided on the base wall 121 to the outer film 96A. In this case, the outer surface 121b of the base wall 121 may abut against the outer film 96B constituting the fourth portion 91B of the second outer pack 90B, the outer surface 122b of the side wall 122 may abut against the outer film 96B constituting the fifth portion 92B of the second outer pack 90B, and the outer surface 124b of the side wall 124 may abut against the sixth portion 93B of the second outer pack 90B. When the base wall 121, side wall 122 and side wall 124 abut against the inner surface of the opposite recess 94B, the connection portion 128a between the base wall 121 and the side wall 122 may abut against the connection portion between the fourth portion 91B and the fifth portion 92B on the inner surface of the recess 94B. Similarly, the connection portion 128b between the base wall 121 and the side wall 124 may abut the connection portion between the fourth portion 91B and the sixth portion 93B on the inner surface of the recess 94B. The connection portion 128c between the side wall 122 and the side wall 124 may abut the connection portion between the fifth portion 92B and the sixth portion 93B on the inner surface of the recess 94B. That is, the connection portion 128a between the base wall 121 and the side wall 122 and the connection portion between the fourth portion 91B and the fifth portion 92B may have equal curvature. The connection portion 128b between the base wall 121 and the side wall 124 and the connection portion between the fourth portion 91B and the sixth portion 93B may have equal curvature. The connection portion 128c between the side wall 122 and the side wall 124 and the connection portion between the fifth portion 92B and the sixth portion 93B may have equal curvature.

[0065] The cover member 102 has the same configuration as the cover member 101 and includes a first cover member 130 and a second cover member 140. The first cover member 130 is fixed to the first outer packaging 90A, and the second cover member 140 is fixed to the second outer packaging 90B. Figure 10 is a perspective view showing the first cover member 130.

[0066] The first cover member 130 includes a base wall 131 extending along the Y-axis direction (more specifically, the XY plane), and side walls 132 and 133 projecting toward the second cover member 140 from both ends of the base wall 131 in the Y-axis direction. A welding plate 108 is provided on the outer surface of the base wall 131, similar to the first cover member 110. The first cover member 130 also has side walls 134 and 135 extending toward the second cover member 140 from both ends of the base wall 131 in the X-axis direction. In the illustrated example, the base wall 131 has a notched portion formed at the end where the side wall 134 is formed for arranging the connector unit 30. The connection portions between the base wall 131 and the side wall 132, the connection portions between the base wall 131 and the side wall 134, and the connection portions between the side wall 132 and the side wall 134 are curved to correspond to the structure of the first cover member 110. The first cover member 130 has a plurality of ribs 137. The ribs 137 are plate-shaped and extend along the YZ plane, and are connected to the base wall 131, side wall 132, and side wall 133. The base wall 131 of the first cover member 130 has a first surface 131a that extends in the Y-axis direction (more specifically in the XY plane) and faces toward the second cover member 140.

[0067] The second cover member 140 has a structure corresponding to the first cover member 130, just as the second cover member 120 has a structure corresponding to the first cover member 110. That is, the second cover member 140 has a structure that faces the first cover member 130 in the Z-axis direction.

[0068] The cover member 103 has the same configuration as the cover member 101 and includes a first cover member 150 and a second cover member 160. The structure of the first cover member 150 and the second cover member 160 is the same as that of the first cover member 110 and the second cover member 120, and only the planar shape differs, so a detailed explanation is omitted. As shown in Figures 1 and 6, in this embodiment, a pair of cover members 103 are arranged adjacent to each other in the X-axis direction. The first cover member 150 is fixed to the first outer packaging pack 90A by a welding plate 108. Similarly, the second cover member 160 is fixed to the second outer packaging pack 90B by a welding plate 108.

[0069] Next, the manufacturing method of the energy storage device 1 will be described. Figure 11 is a flowchart showing an example of the manufacturing process of the energy storage device. In this example of a manufacturing method, first, the cover member 100 and the outer pack 90 are prepared (preparation step S1). The outer pack 90 is prepared with the first outer pack 90A and the second outer pack 90B separated from each other. Subsequently, the cover member 100 is fixed in the recess 94 of the outer pack 90 so that the cover member 100 abuts against the first part 91, the second part 92, and the third part 93 of the outer pack 90 (fixing step S2).

[0070] In other words, in fixing step S2, the first cover member 110, the first cover member 130, and the first cover member 150 are fixed within the recess 94A of the first outer pack 90A. At this time, the first cover member 110 is fixed such that its base wall 111 abuts against the first portion 91A of the first outer pack 90A, its side wall 112 abuts against the second portion 92A of the first outer pack 90A, and its side wall 114 abuts against the third portion 93A. Similarly, the first cover members 130 and 150 are fixed to the first outer pack 90A so as to abut against the first portion 91A, the second portion 92A, and the third portion 93A of the first outer pack 90A. As described above, each first cover member and the first outer pack 90A are fixed together by welding the welding plate 108 to the first outer pack 90A. For example, the first cover member 110 is positioned within the recess 94A of the first outer packaging pack 90A, which is prepared so that the opening of the recess 94A faces upward, and is in contact with the first portion 91A, the second portion 92A, and the third portion 93A. The welding plate 108 of the first cover member 110 is heated from the outer surface of the outer packaging film 96A by a heat source such as a hot plate, and the welding plate 108 and the outer packaging film 96A are welded together, thereby fixing the first cover member 110 to the first outer packaging pack 90A.

[0071] Furthermore, in the fixing process S2, the second cover member 120, the second cover member 140, and the second cover member 160 are fixed within the recess 94B of the second outer packaging 90B. At this time, the second cover member 120 is fixed such that its base wall 121 abuts against the fourth portion 91B of the second outer packaging 90B, its side wall 122 abuts against the fifth portion 92B of the second outer packaging 90B, and its side wall 124 abuts against the sixth portion 93B. Similarly, the second cover members 140 and 160 are fixed so as to abut against the fourth portion 91B, the fifth portion 92B, and the sixth portion 93B of the second outer packaging 90B.

[0072] Next, the energy storage module 1A is housed in the recess 94 to which the cover member 100 is fixed, and the outer surfaces 20sA and 20sB of the energy storage module 1A, viewed from the Y-axis direction, are covered by the cover member 100 (covering process S3). In one example of the covering process S3, the first outer packaging pack 90A to which the first cover members 110, 130, and 150 are fixed is placed with the opening of the recess 94A facing upward, and the energy storage module 1A is positioned between the first cover member 110 and the first cover member 130 and the first cover member 150 within the recess 94A of the first outer packaging pack 90A. In this state, the negative side in the Z-axis direction of the energy storage module 1A is housed in the recess 94A of the first outer packaging pack 90A to which the first cover members 110, 130, and 150 are fixed.

[0073] Then, the second outer pack 90B, to which the second cover members 120, 140, and 160 are fixed, is placed over the first outer pack 90A, on which the energy storage module 1A is positioned, with the opening of the recess 94B facing downwards. In this state, the positive side in the Z-axis direction of the energy storage module 1A is housed in the recess 94B of the second outer pack 90B to which the second cover members 120, 140, and 160 are fixed. As a result, the outer surface 20sA of the energy storage module 1A is covered by the first cover members 110, 130 and the second cover members 120, 140, and the outer surface 20sB of the energy storage module 1A is covered by the first cover member 150 and the second cover member 160. In this state, the flange portion 94Aa of the first outer pack 90A and the flange portion 94Ba of the second outer pack 90B are welded to each other, thereby manufacturing the energy storage device 1.

[0074] As described above, an example of an energy storage device 1 comprises an energy storage module 1A, a first cover member 110, a second cover member 120, a first outer packaging pack 90A, and a second outer packaging pack 90B. The energy storage module 1A includes a plurality of electrodes stacked along the Z-axis direction and has an upper surface 10a intersecting in the Z-axis direction and an outer surface 20sA intersecting in the Y-axis direction. The first cover member 110 has a base wall 111 intersecting in the Z-axis direction, a side wall 112 continuous with the base wall 111 and intersecting in the Y-axis direction, and a side wall 114 continuous with the base wall 111 and the side wall 112 and intersecting in the X-axis direction. The first cover member 110 is arranged to cover one side of the outer surface 20sA of the energy storage module 1A in the Z-axis direction when viewed from the Y-axis direction. The second cover member 120 has a base wall 121 intersecting in the Z-axis direction, a side wall 122 that is continuous with the base wall 121 and intersects in the Y-axis direction, and a side wall 124 that is continuous with the base wall 121 and the side wall 122 and intersects in the X-axis direction. The second cover member 120 is positioned to cover the other side of the outer surface 20sA of the energy storage module 1A in the Z-axis direction when viewed from the Y-axis direction. The first outer packaging pack 90A has a recess 94A formed by a first portion 91A intersecting in the Z-axis direction, a second portion 92A that is continuous with the first portion 91A and intersects in the Y-axis direction, and a third portion 93A that is continuous with the first portion 91A and the second portion 92A and intersects in the X-axis direction. The first outer packaging pack 90A houses the energy storage module 1A and one side of the first cover member 110 in the Z-axis direction within the recess 94A. The second outer pack 90B has a recess 94B formed by a fourth portion 91B intersecting in the Z-axis direction, a fifth portion 92B that is continuous with the fourth portion 91B and intersects in the Y-axis direction, and a sixth portion 93B that is continuous with the fourth portion 91B and the fifth portion 92B and intersects in the X-axis direction. The second outer pack 90B houses the energy storage module 1A and the other side of the second cover member 120 in the Z-axis direction within the recess 94B. The first cover member 110 is fixed to the inner surface of the first outer pack 90A with its base wall 111, side wall 112, and side wall 114 in contact with the first portion 91A, second portion 92A, and third portion 93A of the first outer pack 90A, respectively.The second cover member 120 is fixed to the inner surface of the second outer packaging 90B with its base wall 121, side wall 122, and side wall 124 in contact with the fourth portion 91B, fifth portion 92B, and sixth portion 93B of the second outer packaging, respectively.

[0075] The energy storage device 1 is manufactured by housing an internal component, such as an energy storage module 1A, in a recess 94 formed in the outer pack 90, and then sealing the outer pack 90 under reduced pressure. In this case, if a gap is formed between the recess 94 and the internal component before sealing under reduced pressure, wrinkles may form in the outer pack 90 after sealing under reduced pressure. Wrinkles are particularly likely to form in the corners of the recess 94 (i.e., the corners of the internal component).

[0076] In the above-described energy storage device 1, the first cover member 110 is fixed in contact with all of the first portion 91A, second portion 92A, and third portion 93A that extend in directions intersecting each other in the recess 94A, and the second cover member 120 is fixed in contact with all of the fourth portion 91B, fifth portion 92B, and sixth portion 93B that extend in directions intersecting each other in the recess 94B. Therefore, misalignment of the corner portions of the first cover member 110 (connection portion 118a between the base wall 111 and the side wall 112, connection portion 118b between the base wall 111 and the side wall 114, and connection portion 118c between the side wall 112 and the side wall 114) with respect to the corner portions of the recess 94A (connection portion between the first portion 91A and the second portion 92A, connection portion between the first portion 91A and the third portion 93A, and connection portion between the second portion 92A and the third portion 93A) is suppressed, and the formation of wrinkles in the corner portions of the recess is suppressed.

[0077] Furthermore, the outer packaging 90 is composed of a first outer packaging 90A and a second outer packaging 90B, and the cover member 101 is composed of a first cover member 110 and a second cover member 120. Therefore, the first cover member 110 and the second cover member 120 can be easily positioned relative to the first outer packaging 90A and the second outer packaging 90B.

[0078] The base wall 111, side wall 112, and side wall 114 of the first cover member 110 are connected to each other with an R-shape, and the first part 91A, second part 92A, and third part 93A of the first outer packaging pack 90A may also be connected to each other with an R-shape. In particular, the curvature of the connection portions of the base wall 111, side wall 112, and side wall 114 may be equal to the curvature of the connection portions of the first part 91A, second part 92A, and third part 93A. With such a configuration, the gap between the corner portion of the first cover member 110 and the corner portion of the recess 94A is reduced, and the formation of wrinkles in the corner portion of the recess 94A is suppressed.

[0079] An example outer pack 90 may include a conductive member 95 that constitutes the center of the first portion 91, and an outer film 96 connected to the outer edge of the conductive member 95, which constitutes the periphery of the first portion 91A and the second portion 92A and third portion 93A. The first cover member 110 may be fixed to the inner surface of the outer pack 90 by being compatible with the outer film 96. In this configuration, no adhesive or the like is required to fix the first cover member 110. The power of the energy storage module 1A can be taken out to the outside via the conductive member 95.

[0080] In one example, the first cover member 110 and the second cover member 120 are arranged facing each other in the Z-axis direction and may be in partial contact with each other. In this configuration, the rigidity of the first cover member 110 and the second cover member 120 in the Z-axis direction can be increased.

[0081] Furthermore, the method for manufacturing the above-mentioned energy storage device includes the steps of: preparing an energy storage module 1A, a first cover member 110, a second cover member 120, a first outer pack 90A, and a second outer pack 90B; fixing the first cover member 110 in the recess 94A of the first outer pack 90A; fixing the second cover member 120 in the recess 94B of the second outer pack 90B; housing the negative side in the Z-axis direction of the energy storage module 1A in the recess 94A of the first outer pack 90A to which the first cover member 110 is fixed; stacking the second outer pack 90B on top of the first outer pack 90A so that the positive side in the Z-axis direction of the energy storage module 1A housed in the recess 94A is housed in the recess 94B; and welding the flange portion 94Aa of the first outer pack 90A and the flange portion 94Ba of the second outer pack 90B to each other. In this manufacturing method, misalignment of the corner portion of the cover member 100 relative to the corner portion of the recess 94 is suppressed, and an energy storage device can be obtained in which wrinkles are less likely to form in the corner portion of the recess 94.

[0082] Examples of each form of this disclosure have been described above with reference to the drawings, but this disclosure is not limited to the above forms.

[0083] Figure 12 is a schematic cross-sectional view showing another example of an energy storage device. The energy storage device 1B shown in Figure 12 differs from the energy storage device 1 described above in that it has a cover member 200 instead of a cover member 100. In Figure 12, the cover member 201 corresponding to the cover member 101 is shown. Below, the differences between the cover member 201 and the cover member 101 will be explained, and the explanation of the similarities will be omitted. The cover member 201 has a first cover member 210 corresponding to the first cover member 110 and a second cover member 220 corresponding to the second cover member 120. Compared to the first cover member 110, the first cover member 210 does not have a side wall 113, but has an opposing wall 216. The opposing wall 216 is plate-shaped and faces the base wall 111, and is connected to the ends of the side walls 112, 114, and 115. The opposing wall 216 has the same shape as the base wall 111 when viewed from the Z-axis direction. Furthermore, the second cover member 220 does not have a side wall 123, but has an opposing wall 226. The opposing wall 226 is plate-shaped and faces the base wall 121, and is connected to the ends of the side walls 122, 124, and 125. The opposing wall 226 has the same shape as the base wall 121 when viewed from the Z-axis direction.

[0084] Figure 13 is a schematic cross-sectional view showing yet another example of an energy storage device. The energy storage device 1C shown in Figure 13 differs from the energy storage device 1 described above in that it has a cover member 300 instead of a cover member 100. In Figure 13, the cover member 301 is shown, which corresponds to the cover member 101. Below, the differences between the cover member 301 and the cover member 101 will be explained, and the explanation of the similarities will be omitted. The cover member 301 has a first cover member 310, which corresponds to the first cover member 110, and a second cover member 320, which corresponds to the second cover member 120. Compared to the first cover member 110, the first cover member 310 does not have a side wall 113. Also, compared to the second cover member 120, the second cover member 320 does not have a side wall 123. Other components of the cover member 301 may be the same as those of the cover member 101.

[0085] The form of this disclosure may be shown as follows: [1] A power storage module comprising a plurality of electrodes stacked along a first direction, having a first surface intersecting the first direction, a second surface continuous with the first surface and intersecting the first direction and a second direction, and a third surface continuous with the first surface and the second surface and intersecting the first direction and a second direction, A first cover member having a first wall intersecting in the first direction, a second wall continuous with the first wall and intersecting in the second direction, and a third wall continuous with the first wall and the second wall and intersecting in the third direction, and arranged to cover one side of the second surface of the energy storage module in the first direction when viewed from the second direction, The second cover member has a fourth wall intersecting in the first direction, a fifth wall continuous with the fourth wall and intersecting in the second direction, and a sixth wall continuous with the fourth wall and the fifth wall and intersecting in the third direction, and is arranged to cover the other side of the second surface of the energy storage module in the first direction when viewed from the second direction, A first outer casing having a first recess formed by a first portion intersecting in the first direction, a second portion continuous with the first portion and intersecting in the second direction, and a third portion continuous with the first portion and the second portion and intersecting in the third direction, the first outer casing housing the energy storage module and one side of the cover member in the first direction within the first recess, The second exterior body has a second recess formed by a fourth portion intersecting in the first direction, a fifth portion continuous with the fourth portion and intersecting in the second direction, and a sixth portion continuous with the fourth portion and the fifth portion and intersecting in the third direction, and the second exterior body houses the energy storage module and the other side of the cover member in the first direction within the second recess, The first cover member is fixed to the inner surface of the first exterior body such that the first wall, second wall, and third wall are in contact with the first, second, and third portions of the first exterior body, respectively. The energy storage device is fixed to the inner surface of the second outer casing, with the second cover member in contact with the fourth, fifth, and sixth portions of the second outer casing, respectively, and with the fourth, fifth, and sixth walls of the second outer casing. [2] The first wall, the second wall, and the third wall of the first cover member are connected to each other with an R-shape. The first part, second part, and third part of the first exterior body are connected to each other in an R shape, as described in [1]. [3] The energy storage device according to [2], wherein the curvature of the connection portions between the first wall, second wall and third wall of the first cover member is equal to the curvature of the connection portions between the first part, second part and third part of the first exterior body. [4] The first exterior body includes a conductive member that constitutes the center of the first portion, and a sealing member connected to the outer edge of the conductive member that constitutes the periphery of the first portion and the second and third portions. The energy storage device according to any one of [1] to [3], wherein the first cover member is fixed to the inner surface of the first outer casing by being compatible with the sealing member. [5] The energy storage device according to any one of [1] to [4], wherein the first cover member and the second cover member are arranged facing each other in the first direction and are in partial contact with each other. [Explanation of symbols]

[0086] 1...Energy storage device, 1A...Energy storage module, 11...Bipolar electrode (electrode), 12...Positive terminal electrode (electrode), 13...Negative terminal electrode (electrode), 100...Cover component, 90...Outer packaging (outer body).

Claims

1. A power storage module comprising a plurality of electrodes stacked along a first direction, having a first surface intersecting the first direction, a second surface continuous with the first surface and intersecting the first direction and a second direction, and a third surface continuous with the first surface and the second surface and intersecting the first direction and a second direction. A first cover member having a first wall intersecting in the first direction, a second wall continuous with the first wall and intersecting in the second direction, and a third wall continuous with the first wall and the second wall and intersecting in the third direction, and arranged to cover one side of the second surface of the energy storage module in the first direction when viewed from the second direction, The second cover member has a fourth wall intersecting in the first direction, a fifth wall continuous with the fourth wall and intersecting in the second direction, and a sixth wall continuous with the fourth wall and the fifth wall and intersecting in the third direction, and is arranged to cover the other side of the second surface of the energy storage module in the first direction when viewed from the second direction, A first outer casing having a first recess formed by a first portion intersecting in the first direction, a second portion continuous with the first portion and intersecting in the second direction, and a third portion continuous with the first portion and the second portion and intersecting in the third direction, the first outer casing housing the energy storage module and one side of the cover member in the first direction within the first recess, The second outer casing has a second recess formed by a fourth portion intersecting in the first direction, a fifth portion continuous with the fourth portion and intersecting in the second direction, and a sixth portion continuous with the fourth portion and the fifth portion and intersecting in the third direction, and the second outer casing houses the energy storage module and the other side of the cover member in the first direction within the second recess, The first cover member is fixed to the inner surface of the first exterior body such that the first wall, second wall, and third wall are in contact with the first, second, and third portions of the first exterior body, respectively. The energy storage device is fixed to the inner surface of the second outer casing, with the second cover member in contact with the fourth, fifth, and sixth portions of the second outer casing, respectively, and with the fourth, fifth, and sixth walls of the second outer casing.

2. The first wall, the second wall, and the third wall of the first cover member are connected to each other with an R-shape. The energy storage device according to claim 1, wherein the first part, second part, and third part of the first exterior body are connected to each other in an R shape.

3. The energy storage device according to claim 2, wherein the curvature of the connection portions between the first wall, second wall, and third wall of the first cover member is equal to the curvature of the connection portions between the first part, second part, and third part of the first exterior body.

4. The first exterior body includes a conductive member that constitutes the center of the first portion, and a sealing member connected to the outer edge of the conductive member that constitutes the periphery of the first portion and the second and third portions. The energy storage device according to claim 1, wherein the first cover member is fixed to the inner surface of the first outer casing by being compatible with the sealing member.

5. The energy storage device according to claim 1, wherein the first cover member and the second cover member are arranged facing each other in the first direction and are in partial contact with each other.

6. A storage module comprising a plurality of electrodes stacked along a first direction, having a first surface intersecting the first direction, a second surface continuous with the first surface and intersecting the first direction and intersecting the second direction, and a third surface continuous with the first surface and the second surface and intersecting the first direction and the second direction and intersecting the third direction; a first cover member having a first wall intersecting the first direction, a second wall continuous with the first wall and intersecting the second direction, and a third wall continuous with the first wall and the second wall and intersecting the third direction; a second cover member having a fourth wall intersecting the first direction, a fifth wall continuous with the fourth wall and intersecting the second direction, and a sixth wall continuous with the fourth wall and the fifth wall and intersecting the third direction; A step of preparing a first exterior body having a first recess formed by a first portion intersecting in the first direction, a second portion continuous with the first portion and intersecting in the second direction, and a third portion continuous with the first and second portions and intersecting in the third direction, with a first flange portion formed on the edge of the second and third portions opposite to the first portion; and a second exterior body having a second recess formed by a fourth portion intersecting in the first direction, a fifth portion continuous with the fourth portion and intersecting in the second direction, and a sixth portion continuous with the fourth and fifth portions and intersecting in the third direction, with a second flange portion formed on the edge of the fifth and sixth portions opposite to the fourth portion; The first cover member is fixed in the first recess of the first exterior body such that the first wall, second wall, and third wall of the first cover member abut against the first portion, second portion, and third portion of the first exterior body, respectively. A step of fixing the second cover member in the second recess of the second exterior body such that the fourth wall, fifth wall, and sixth wall of the second cover member abut against the fourth portion, fifth portion, and sixth portion of the second exterior body, respectively, A step of housing one side of the energy storage module in the first direction within the first recess of the first outer casing to which the first cover member is fixed, A step of superimposing the second outer casing onto the first outer casing such that the other side of the energy storage module housed in the first recess is housed in the second recess, A method for manufacturing an energy storage device, comprising the step of welding the first flange portion of the first outer casing and the second flange portion of the second outer casing to each other.

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