Electricity storage device manufacturing method

Abstract

This electricity storage device manufacturing method includes: a preparation step for forming, in a first exterior member, a first recessed portion for accommodating an electricity storage module and a rectangular frame-shaped first flange portion surrounding the first recessed portion, and forming, in a second exterior member, a second recessed portion for accommodating the electricity storage module and a rectangular frame-shaped second flange portion surrounding the second recessed portion; a cutting step for cutting an outer peripheral portion of the first flange portion to form a first outer edge, and cutting an outer peripheral portion of the second flange portion to form a second outer edge; and an accommodating step for accommodating the electricity storage module in the first recessed portion and the second recessed portion, and overlapping the first flange portion and the second flange portion in a first direction.

Description

Electricity storage device manufacturing method

[0001] The present disclosure relates to a method for manufacturing an electricity storage device.

[0002] Patent Document 1 describes a bipolar battery. In this bipolar battery, a laminate composed of alternately stacked bipolar electrodes and electrolyte layers is housed in a laminate sheet having openings on the surfaces of current collectors at both ends of the laminate. The laminate sheet is a polymer-metal composite film composed of a heat-welding resin film, a metal foil, and a rigid resin film stacked in this order.

[0003] Japanese Patent Application Laid-Open No. 2004-134210

[0004] A typical method for manufacturing the bipolar battery involves placing a bipolar electrode stack within a pair of laminate sheets, welding the edges of the laminate sheets, and then cutting the welded portions of the laminate sheets. In this case, the edge surfaces of the laminate sheets are aligned with each other, which can electrically connect the metal layers exposed at the edge surfaces of the laminate sheets, potentially causing a short circuit through the laminate sheets. Therefore, in the above technical field, it is desirable to prevent a short circuit through an exterior body such as a laminate sheet.

[0005] An object of the present disclosure is to provide a method for manufacturing an electricity storage device that can suppress short circuits through an exterior body.

[0006] The energy storage device manufacturing method according to the present disclosure is a method for manufacturing an energy storage device including an energy storage module including a plurality of electrodes stacked along a first direction, and an exterior body including a first exterior member and a second exterior member and accommodating the energy storage module therein, the method including a preparation step of forming, in the first exterior member, a first recess for accommodating the energy storage module and a first flange portion having a rectangular frame shape surrounding the first recess, and forming, in the second exterior member, a second recess for accommodating the energy storage module and a second flange portion having a rectangular frame shape surrounding the second recess; the cutting step includes a cutting process for forming an outer periphery of the first flange portion and an outer periphery of the second flange portion, an accommodating process for accommodating the energy storage module in the first recess and the second recess and overlapping the first flange portion and the second flange portion in a first direction, and a joining process for joining the adhesive layer of the first flange portion and the adhesive layer of the second flange portion at the overlapping portion of the first flange portion and the second flange portion to integrate the first exterior member and the second exterior member to form an exterior body, wherein in the cutting step, when the first flange portion and the second flange portion joined in the joining step are overlapping each other, the outer periphery of the first flange portion and the outer periphery of the second flange portion are cut so that the second outer edge is positioned outside the first outer edge when viewed from the first direction.

[0007] In this method, an energy storage device is manufactured by providing an exterior body for an energy storage module. To this end, first, a first exterior member and a second exterior member including a metal layer that forms the exterior body are prepared. Next, a first recess for accommodating the energy storage module and a first flange portion having a rectangular frame shape surrounding the first recess are formed in the first exterior member. A similar second recess and second flange portion are formed in the second exterior member. Next, the outer periphery of the first flange portion is cut to form a first outer edge, and the outer periphery of the second flange portion is cut to form a second outer edge. The energy storage module is then accommodated in the first recess and the second recess, and the first flange portion and the second flange portion are overlapped and joined to each other. This integrates the first exterior member and the second exterior member to form an exterior body that accommodates the energy storage module therein.

[0008] In this method, as described above, before the first flange portion and the second flange portion are overlapped and joined, the outer peripheries of the first flange portion and the second flange portion are cut to form a first outer edge on the first flange portion and a second outer edge on the second flange portion. Therefore, when the first flange portion and the second flange portion are overlapped with each other, the outer peripheries of the first flange portion and the second flange portion can be cut so that the second outer edge is positioned outward from the first outer edge when viewed from the first direction. As a result, when the first flange portion and the second flange portion are joined in a later process, the first end face, which is the end face of the first outer edge of the first flange portion, and the second end face, which is the end face of the second outer edge of the second flange portion, are offset from each other. This ensures that the metal layer on the first end face and the metal layer on the second end face are spaced apart from each other, ensuring an insulating distance. This prevents short circuits through the exterior body.

[0009] The energy storage device manufacturing method according to the present disclosure includes a bending process for bending the first flange portion and the second flange portion that are joined to each other, and in the cutting process, corners of the first flange portion and the second flange portion that are formed into a rectangular frame shape in the preparation process may be cut.

[0010] In the energy storage device manufacturing method according to the present disclosure, the joining process may include a first joining process in which a peripheral region including an overlapping portion of the first flange portion and the second flange portion is heat-pressed into a rectangular frame shape to join the first flange portion and the second flange portion, and a second joining process in which a corner region located inside a corner of the peripheral region is heat-pressed to join the first flange portion and the second flange portion.

[0011] In the energy storage device manufacturing method according to the present disclosure, in the bending step, the first flange portion and the second flange portion may be bent so that the second flange portion is bent to the opposite side from the first flange portion.

[0012] In the energy storage device manufacturing method according to the present disclosure, in the bending process, the first flange portion and the second flange portion are bent at one bending portion that is aligned with the energy storage module when viewed from a first direction, and at another bending portion that is aligned with the energy storage module when viewed from the first direction and extends in a direction that intersects with the first bending portion, and it is not necessary to bend the first flange portion at the intersection where the one bending portion intersects with the other bending portion.

[0013] In the energy storage device manufacturing method according to the present disclosure, the preparation step includes a first preparation step of preparing a first conductive plate and a first laminate member, and providing the first laminate member on the outer edge of the first conductive plate when viewed in a direction intersecting the plate surface of the first conductive plate, thereby constituting a first exterior member, and a second preparation step of preparing a second conductive plate and a second laminate member, and providing the second laminate member on the outer edge of the second conductive plate when viewed in a direction intersecting the plate surface of the second conductive plate, thereby constituting a second exterior member, and in the accommodation step, the energy storage module may be arranged so that the current collector of the electrode located at one end of the energy storage module in the first direction contacts the first conductive plate, and the current collector of the electrode located at the other end of the energy storage module in the first direction contacts the second conductive plate.

[0014] In the energy storage device manufacturing method according to the present disclosure, the first laminate member may be composed of a first portion and a second portion, and the second laminate member may be composed of another first portion and another second portion, and in the first preparation step, a frame-shaped first laminate member may be constructed by joining the one first portion and the one second portion, and in the second preparation step, a frame-shaped second laminate member may be constructed by joining the other first portion and the other second portion.

[0015] In the energy storage device manufacturing method according to the present disclosure, in the first preparation step and the second preparation step, when the first flange portion and the second flange portion are overlapped in the first direction in the accommodation step, the joining of one first portion and one second portion, and the joining of another first portion and another first portion may be performed so that the joint between one first portion and one second portion and the joint between another first portion and another second portion do not overlap when viewed from the first direction.

[0016] According to the present disclosure, it is possible to provide a method for manufacturing an electricity storage device that can suppress short circuits through an exterior body.

[0017] FIG. 1 is a schematic plan view of an energy storage device according to this embodiment. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a schematic plan view of the energy storage module shown in FIGS. 1 and 2. FIG. 4 is a schematic cross-sectional view of the energy storage module shown in FIGS. 1 and 2. FIG. 5 is a schematic plan view showing the exterior body shown in FIG. 1. FIG. 6 is a schematic cross-sectional view taken along line V-V in FIG. 1. FIG. 7 is a schematic cross-sectional view showing an enlarged portion of FIG. 6. FIG. 8 is a schematic plan view of the energy storage device shown in FIG. 1, showing the exterior body in a see-through manner and adding insulating material. FIG. 9 is a schematic plan view illustrating one step of a method for manufacturing an energy storage device according to this embodiment. FIG. 10 is a schematic plan view illustrating one step of a method for manufacturing an energy storage device according to this embodiment. FIG. 11 is a schematic plan view illustrating one step of a method for manufacturing an energy storage device according to this embodiment. FIG. 12 is a schematic plan view illustrating one step of a method for manufacturing an energy storage device according to this embodiment. Fig. 13 is a plan view showing a first exterior member and a second exterior member according to a modified example. Fig. 14 is a plan view showing a state in which the first exterior member and the second exterior member shown in Fig. 13 are superimposed on each other. Fig. 15 is a schematic cross-sectional view showing a bent portion according to a modified example. Fig. 16 is a schematic cross-sectional view showing a bent portion according to a modified example. Fig. 17 is a schematic cross-sectional view showing a bent portion according to a modified example. Fig. 18 is a schematic cross-sectional view showing a bent portion according to a modified example.

[0018] Hereinafter, an energy storage device and an energy storage device manufacturing method according to an embodiment will be described with reference to the drawings. In the description of each drawing, the same or corresponding elements are denoted by the same reference numerals, and duplicated descriptions may be omitted. In addition, each drawing may show an orthogonal coordinate system that defines a first direction D1, a second direction D2 perpendicular to the first direction D1, and a third direction D3 perpendicular to the first direction D1 and the second direction D2.

[0019] FIG. 1 is a schematic plan view of the power storage device according to this embodiment, and FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a schematic plan view of the power storage module shown in FIGS. 1 and 2, and FIG. 4 is a schematic cross-sectional view of the power storage module shown in FIGS. 1 and 2. The power storage device 100 shown in FIGS. 1 to 4 is used, for example, as a battery for various vehicles such as a forklift, a hybrid vehicle, or an electric vehicle. The power storage device 100 is, for example, a secondary battery such as a nickel-metal hydride secondary battery or a lithium-ion secondary battery. The power storage device 100 may be an electric double layer capacitor or an all-solid-state battery. Here, a case where the power storage device 100 is a lithium-ion secondary battery is illustrated.

[0020] 1 to 4, the energy storage device 100 includes an energy storage module 1 and an exterior body 40 provided on the energy storage module 1. The energy storage device 100 is configured by sealing the energy storage module 1 with the exterior body 40.

[0021] The energy storage module 1 includes an electrode stack 10 formed by stacking multiple electrodes along a first direction D1, a sealing body 20 provided on the outer periphery of the electrode stack 10, and a pair of cover members 50 arranged to sandwich the electrode stack 10 and the sealing body 20 when viewed from the first direction D1 (along the third direction D3).

[0022] The electrode stack 10 includes a plurality of electrodes stacked along a first direction D1. The plurality of electrodes includes a plurality of bipolar electrodes 11, a negative terminal electrode (second terminal electrode) 12, and a positive terminal electrode (first terminal electrode) 13. Separators 14 are interposed between adjacent electrodes.

[0023] The bipolar electrode 11 includes a current collector 15, a positive electrode active material layer (first active material layer) 16, and a negative electrode active material layer (second active material layer) 17. The current collector 15 has, for example, a rectangular sheet shape. The current collector 15 includes a first surface 15a and a second surface 15b. As an example, the first surface 15a is a surface that intersects with the first direction D1, and the second surface 15b is a surface that intersects with the first direction D1 and is opposite to the first surface 15a. In this example, the first surface 15a of the current collector 15 faces one side of the first direction D1 (the direction from the positive electrode terminal electrode 13 to the negative electrode terminal electrode 12 in FIG. 4), and the second surface 15b of the current collector 15 faces the other side of the first direction (the direction from the negative electrode terminal electrode 12 to the positive electrode terminal electrode 13 in FIG. 4).

[0024] The positive electrode active material layer 16 is provided on the first surface 15a of the current collector 15. The negative electrode active material layer 17 is provided on the second surface 15b of the current collector 15. The peripheral portion surrounding the positive electrode active material layer 16 on the first surface 15a of the current collector 15 and the peripheral portion surrounding the negative electrode active material layer 17 on the second surface 15b of the current collector 15 are each an unformed region (uncoated region) where no active material layer is provided. The multiple bipolar electrodes 11 are stacked such that the positive electrode active material layer 16 of one bipolar electrode 11 and the negative electrode active material layer 17 of another bipolar electrode 11 face each other via the separator 14. The positive electrode active material layer 16 and the negative electrode active material layer 17 of each bipolar electrode 11 may have grooves formed therein to improve liquid injection and gas escape properties.

[0025] The positive electrode active material layer 16 and the negative electrode active material layer 17 are rectangular when viewed from the first direction D1. The negative electrode active material layer 17 is slightly larger than the positive electrode active material layer 16 when viewed from the first direction D1. In a plan view viewed from the first direction D1, the entire formation region of the positive electrode active material layer 16 is located within the formation region of the negative electrode active material layer 17. In other words, when viewed from the first direction D1, the outer edge 17e of the negative electrode active material layer 17 is located outside the outer edge 16e of the positive electrode active material layer 16.

[0026] The negative electrode terminal electrode 12 has a current collector 15 and a negative electrode active material layer 17 provided on a second surface 15b of the current collector 15. The negative electrode terminal electrode 12 does not have a positive electrode active material layer 16 or a negative electrode active material layer 17 on a first surface 15a of the current collector 15. In other words, no active material layer is provided on the first surface 15a of the current collector 15 of the negative electrode terminal electrode 12, and the first surface 15a forms the negative electrode terminal surface of the energy storage module 1. The negative electrode terminal electrode 12 is stacked on the bipolar electrode 11 at one end of the electrode stack 10 in the first direction D1. The negative electrode terminal electrode 12 is stacked on the bipolar electrode 11 via a separator 14 so that the negative electrode active material layer 17 faces the positive electrode active material layer 16 of the bipolar electrode 11.

[0027] The positive terminal electrode 13 has a current collector 15 and a positive electrode active material layer 16 provided on a first surface 15a of the current collector 15. The positive terminal electrode 13 does not have a positive electrode active material layer 16 or a negative electrode active material layer 17 on a second surface 15b, which is the surface opposite the first surface 15a of the current collector 15. In other words, no active material layer is provided on the second surface 15b of the current collector 15 of the positive terminal electrode 13, and this second surface 15b constitutes a positive electrode terminal surface of the energy storage module 1. The positive terminal electrode 13 is stacked on the bipolar electrode 11 at the other end of the electrode stack 10 in the first direction D1. The positive terminal electrode 13 is stacked on the bipolar electrode 11 such that the positive electrode active material layer 16 faces the negative electrode active material layer 17 of the bipolar electrode 11 with the separator 14 interposed therebetween.

[0028] In this embodiment, the current collectors of the bipolar electrode 11, the negative terminal electrode 12, and the positive terminal electrode 13 are denoted by the same reference numeral 15, but the materials constituting the current collectors of the bipolar electrode 11, the negative terminal electrode 12, and the positive terminal electrode 13 may be the same as or different from one another.

[0029] The separators 14 are respectively disposed between the bipolar electrodes 11 adjacent to each other in the first direction D1, between the negative terminal electrode 12 and the bipolar electrode 11, and between the positive terminal electrode 13 and the bipolar electrode 11. That is, the separators 14 are interposed between the positive electrode surface of the current collector 15 on which the positive electrode active material layer 16 is provided and the negative electrode surface on which the negative electrode active material layer 17 is provided. The separators 14 are members that allow charge carriers such as lithium ions to pass through, and by isolating the positive electrode surface from the negative electrode surface, they prevent short circuits due to contact between adjacent electrodes.

[0030] The current collector 15 is a chemically inactive electrical conductor that allows current to continue to flow through the positive electrode active material layer 16 and the negative electrode active material layer 17 during discharge or charge 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 resins obtained by adding a conductive filler to a conductive polymer material or a non-conductive polymer material as needed. The current collector 15 may have multiple layers. In this case, each layer of the current collector 15 may contain the above-mentioned metal material and / or conductive resin material.

[0031] A coating layer may be formed on the surface of the current collector 15. The coating layer may be formed by a known method such as plating or spray coating. The current collector 15 may be, for example, in the form of a plate, foil, film, or mesh. Examples of metal foils include aluminum foil (e.g., aluminum alloy A110 or A3104), copper foil, nickel foil, titanium foil, and stainless steel foil. The current collector 15 may be an alloy foil of the above metals or a foil formed by integrating multiple metal foils. When the current collector 15 is in the form of a foil, the thickness of the current collector 15 may be, for example, 1 μm to 200 μm. The current collector 15 may be a foil formed by integrating aluminum foil and copper foil by bonding them together with a conductive adhesive, or a foil formed by vapor-depositing a copper layer on one side of aluminum foil.

[0032] The positive electrode active material layer 16 contains a positive electrode active material capable of absorbing and releasing charge carriers such as lithium ions. Examples of the positive electrode active material include lithium composite metal oxides having a layered rock salt structure, metal oxides having a spinel structure, and polyanion compounds. The positive electrode active material may be any material that can be used in lithium ion secondary batteries. The positive electrode active material layer 16 may contain a plurality of positive electrode active materials. In this embodiment, the positive electrode active material layer 16 contains an olivine-type lithium iron phosphate (LiFePO ) as a composite oxide. ４ )

[0033] The negative electrode active material layer 17 includes a negative electrode active material capable of absorbing and releasing charge carriers such as lithium ions. The negative electrode active material may be a simple substance, an alloy, or a compound. Examples of the negative electrode active material include Li, carbon, and metal compounds. The negative electrode active material may be an element or a compound thereof that can be alloyed with lithium. Examples of carbon include natural graphite, artificial graphite, hard carbon (non-graphitizable carbon), and soft carbon (easily graphitizable carbon). Examples of artificial graphite include highly oriented graphite and mesocarbon microbeads. Examples of elements that can be alloyed with lithium include silicon and tin. In this embodiment, the negative electrode active material layer 17 includes graphite as a carbon-based material.

[0034] Each of the positive electrode active material layer 16 and the negative electrode active material layer 17 (hereinafter sometimes simply referred to as "active material layer") may further contain a conductive additive, a binder, an electrolyte, an electrolyte supporting salt, etc., as necessary. The conductive additive is added to enhance electrical conductivity. Examples of the conductive additive include acetylene black, carbon black, and graphite. The electrolyte supporting salt is added to enhance ionic conductivity.

[0035] Examples of binders include fluorine-containing resins 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 and methacrylic acid; styrene-butadiene rubber; carboxymethyl cellulose; alginates such as sodium alginate and ammonium alginate; water-soluble cellulose ester crosslinked bodies; and starch-acrylic acid graft polymers. These binders can be used alone or in combination. Examples of solvents for binders include water and N-methyl-2-pyrrolidone.

[0036] The separator 14 may be, for example, a porous sheet or nonwoven fabric containing a polymer that absorbs and retains an electrolyte. Examples of materials for the separator 14 include polypropylene, polyethylene, polyolefin, and polyester. The separator 14 may have a single-layer structure or a multi-layer structure. The multi-layer 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 electrolyte impregnated in the separator 14 is a liquid electrolyte (electrolytic solution) containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent.

[0037] The electrolyte salt of the electrolyte solution is LiClO ４ , LiAsF ６ , LiPF ６ , LiBF ４ , LiCF ３ SO ３ , LiN(FSO ２ ) ２ , LiN(CF ３ SO ２ ) ２ Known lithium salts such as those listed above may be used. Furthermore, known solvents such as cyclic carbonates, cyclic esters, chain carbonates, chain esters, and ethers may be used as the nonaqueous solvent. Two or more of these known solvent materials may be used in combination.

[0038] The sealing body 20 is provided on the electrode stack 10 so as to surround the electrode stack 10 when viewed from the Z direction. For example, the sealing body 20 is formed as a rectangular tubular member on the peripheral portion of the electrode stack 10 so as to surround four side surfaces of the electrode stack 10, which is a substantially rectangular parallelepiped. The sealing body 20 can be joined (welded) to each of the first surface 15a and the second surface 15b of the current collector 15 at the peripheral portion 15c of each current collector 15. The sealing body 20 insulates adjacent current collectors 15 in the first direction D1 and forms an internal space S in cooperation with the adjacent current collectors 15. The sealing body 20 seals each of the internal spaces S. An electrolyte is accommodated in each internal space S. The sealing body 20 can prevent the electrolyte accommodated in the internal space S from leaking out to the outside. Furthermore, the sealing body 20 can prevent air, moisture, and the like from entering the internal space S from the outside of the electrode stack 10 .

[0039] The sealing body 20 includes an insulating material, and examples of the material for the sealing body 20 include various resin materials such as polypropylene, polyethylene, polystyrene, ABS resin, acid-modified polypropylene, acid-modified polyethylene, and acrylonitrile-styrene resin.

[0040] The sealing body 20 includes a plurality of resin sealants 21 and a plurality of resin spacers 22. The sealants 21 are provided on each of the plurality of electrodes. More specifically, the sealants 21 are provided on the peripheral edge portions 15c of the current collectors 15. Thus, the plurality of sealants 21 are stacked along the first direction D1. The sealants 21 provided on the peripheral edge portions 15c of the current collectors 15 are formed in a frame shape that follows the outline of the current collectors 15 when viewed from the first direction D1. Here, because the current collectors 15 are rectangular in plan view, the sealants 21 also have a rectangular frame shape when viewed from the first direction D1. The sealants 21 include an inner portion that overlaps the peripheral edge portions 15c of the current collectors 15 when viewed from the first direction D1, and an outer portion that extends beyond the edge of the current collectors 15. The sealing material 21 is formed by joining together and integrating an outer portion of one resin member joined to the first surface 15 a of the current collector 15 and another resin member joined to the second surface 15 b of the current collector 15. In other words, the sealing material 21 covers the peripheral portion 15 c of the current collector 15.

[0041] In this embodiment, the sealing materials provided on the current collector 15 of the bipolar electrode 11, the current collector 15 of the negative terminal electrode 12, and the current collector 15 of the positive terminal electrode 13 are each given the same reference numeral as a sealing material 21. However, the sealing material provided on the current collector 15 of the bipolar electrode 11, the sealing material provided on the current collector 15 of the negative terminal electrode 12, and the sealing material provided on the current collector 15 of the positive terminal electrode 13 may be the same as or different from one another.

[0042] The spacer 22 is formed in a generally frame-like shape so as to surround the positive electrode active material layer 16 when viewed from the first direction D1. The spacer 22 has an inner portion overlapping the current collector 15 and an outer portion extending beyond the edge of the current collector 15 when viewed from the first direction D1. The spacer 22 is disposed so as to be interposed between the sealing materials 21 provided on the electrodes adjacent to each other in the first direction D1. As a result, the spacer 22, together with the pair of sealing materials 21 adjacent to each other in the first direction D1, maintains the spacing between the current collectors 15 adjacent to each other in the first direction D1. An internal space S is defined by the pair of current collectors 15 adjacent to each other in the first direction D1, the spacer 22, and the pair of sealing materials 21 adjacent to the spacer 22.

[0043] When viewed from the first direction D1, the spacer 22 is formed in a frame shape that follows the outer shape of the current collector 15. Therefore, the sealing body 20 is configured by laminating multiple resin frames (sealing material 21 and spacers 22) provided on the peripheral portion 15 c of the current collector 15 along the first direction D1, and seals the internal space S between the electrodes adjacent in the first direction D1.

[0044] When viewed from the first direction D1, the inner edge 22e of the spacer 22 is located between the outer edge 17e of the negative electrode active material layer 17 and the outer edge 16e of the positive electrode active material layer 16. That is, the inner edge 22e of the spacer 22 is located more inward than the outer edge 17e of the negative electrode active material layer 17. As a result, the spacer 22 includes a portion that overlaps with the negative electrode active material layer 17 when viewed from the first direction D1. The multiple spacers 22 may be configured not to contact the current collectors 15 of adjacent bipolar electrodes 11. In other words, a small gap may be provided between the spacer 22 and the first surface 15a of the current collector 15 of the adjacent bipolar electrode.

[0045] The outer edges of the multiple sealants 21 and the multiple spacers 22 are welded together and integrated to form a welded portion 23. That is, the sealing body 20 includes the welded portion 23 formed by welding the multiple sealants 21 and the multiple spacers 22 together. When viewed from the first direction D1, the welded portion 23 has a frame shape (here, a rectangular frame shape) surrounding the electrode stack 10 and forms the outer periphery of the sealing body 20. Therefore, the outer surface 23s of the welded portion 23 forms the outer surface of the sealing body 20. That is, in this embodiment, the sealing body 20 has four outer surfaces 23s extending along the first direction D1. The spacers 22 do not need to be welded to the sealing material 21, at least in the inner portion of the sealing material 21 adjacent to the first direction D1.

[0046] The end of the separator 14 may be held by being sandwiched between the sealant 21 and the spacer 22. The end of the separator 14 may be fixed by being welded to at least one of the sealant 21 and the spacer 22.

[0047] The pair of cover members 50 are arranged to face each other along the third direction D3, sandwiching the electrode stack 10 and the sealing body 20 when viewed from the first direction D1. The cover members 50 are formed hollow, for example, from resin or the like. The cover members 50 constitute the module corners 1c (four in this case), which are corners of the energy storage module 1. The module corners 1c are chamfered, for example, to have a rounded surface. One of the pair of cover members 50 is formed with an extraction portion for extracting wiring DL (for example, a flexible substrate) including voltage detection lines and the like extending from the electrode stack 10 to the outside.

[0048] FIG. 5 is a schematic plan view showing the exterior body shown in FIG. 1. As shown in FIGS. 1, 2, and 5, the exterior body 40 is provided to cover the above-described energy storage module 1. The exterior body 40 includes a first exterior portion 41 and a second exterior portion 42 arranged to sandwich the energy storage module 1 from both sides in the first direction D1. As described below, the first exterior portion 41 and the second exterior portion 42 are folded in the energy storage device 100, but FIG. 5 shows them in an unfolded state. The first exterior portion 41 and the second exterior portion 42 each include a laminate member and a conductive plate. Here, the first exterior portion 41 includes a first laminate member 91 and a first conductive plate 31, and the second exterior portion 42 includes a second laminate member 92 and a second conductive plate 32.

[0049] The first laminating member 91 and the second laminating member 92 are each a laminate film formed by sequentially laminating an adhesive layer 93, a metal layer 94, and a resin layer 95. The adhesive layer 93 is an insulating layer laminated on the inner surface of the metal layer 94. The adhesive layer 93 and the resin layer 95 are made of mutually compatible resins. The adhesive layer 93 is made of, for example, an acid-modified resin, for example, an acid-modified polyolefin resin. The metal layer 94 is, for example, an aluminum foil (e.g., aluminum alloy A8079). The resin layer 95 is laminated on the outer surface of the metal layer 94. The resin layer 95 is made of, for example, an acid-modified resin, for example, an acid-modified polyolefin resin. The first laminating member 91 and the second laminating member 92 may also include layers made of other resins, such as polyolefin or nylon.

[0050] A first conductive plate 31 and a second conductive plate 32 are laminated on the second surface 15b of the current collector 15 of the negative terminal electrode 12 and on the exposed portion of the first surface 15a of the current collector 15 of the positive terminal electrode 13 that is not covered by the sealing body 20 (i.e., the portion where the sealing material 21 is not provided when viewed from the first direction D1). That is, the first conductive plate 31 is laminated on the positive terminal electrode 13 that is arranged in the outermost layer on one side of the first direction D1 of the energy storage module 1, and the second conductive plate 32 is laminated on the negative terminal electrode 12 that is arranged in the outermost layer on the other side of the first direction D1 of the energy storage module 1. The first conductive plate 31 is in contact with the second surface 15b of the positive terminal electrode 13 and is laminated on the positive terminal electrode 13 so as to be electrically connected to the positive terminal electrode 13 via the second surface 15b. The second conductive plate 32 is in contact with the first surface 15 a of the negative terminal electrode 12 and is laminated on the negative terminal electrode 12 so as to be electrically connected to the negative terminal electrode 12 via the first surface 15 a. The first conductive plate 31 and the second conductive plate 32 are in direct contact with the surface of the current collector 15 on which no active material layer is formed, and are electrically connected.

[0051] The first conductive plate 31 includes a first surface 31s opposite the positive terminal electrode 13, and the second conductive plate 32 includes a second surface 32s opposite the negative terminal electrode 12. The first surface 31s of the first conductive plate 31 and the second surface 32s of the second conductive plate 32 can each be used to extract current from the energy storage module 1. Furthermore, when a battery pack is formed using a plurality of energy storage devices 100 by stacking a plurality of energy storage devices 100 in the first direction D1 and connecting them in series, a conductive plate, conductive adhesive, or the like is disposed between two adjacent energy storage devices 100 in the first direction D1 to electrically connect the plurality of energy storage devices 100. That is, the first conductive plate 31 and the second conductive plate 32 can be used to electrically connect the plurality of energy storage devices 100.

[0052] The first exterior part 41 is formed of a first laminate member 91 and a first conductive plate 31 and includes a first recess 41p that houses the energy storage module 1, and a first flange portion 41f that is formed of the first laminate member 91 and surrounds the first recess 41p when viewed from the first direction D1. The second exterior part 42 is formed of a second laminate member 92 and a second conductive plate 32 and includes a second recess 42p that houses the energy storage module 1, and a second flange portion 42f that is formed of the second laminate member 92 and surrounds the second recess 42p when viewed from the first direction D1. The first exterior part 41 and the second exterior part 42 are bonded together by joining the adhesive layer 93 to each other at the overlapping first flange portion 41f and the second flange portion 42f. That is, the peripheral edge of the first exterior part 41 and the peripheral edge of the second exterior part 42 are bonded together by joining the adhesive layers 93 of the first laminating member 91 and the second laminating member 92 together.

[0053] The corners of the first recess 41p and the second recess 42p are curved and convex outward from the first recess 41p and the second recess 42p (i.e., have a radius). A width W42 of the second flange 42f, which is the distance from the outer edge of the second recess 42p to the outer edge (second outer edge 42e) of the second flange 42f, is greater than a width W41 of the first flange 41f, which is the distance from the outer edge (first outer edge 41e) of the first recess 41p to the outer edge of the first flange 41f. The cover member 50 is disposed between the energy storage module 1 and the exterior body 40 within the first recess 41p and the second recess 42p when viewed from the first direction D1.

[0054] The first flange portion 41 f and the second flange portion 42 f have a rectangular frame shape when viewed from the first direction D1. The first flange portion 41 f has four straight line portions 411, 412, 413, and 414 extending along the rectangular energy storage module 1 when viewed from the first direction D1. The second flange portion 42 f has four straight line portions 421, 422, 423, and 424 extending along the rectangular energy storage module 1 when viewed from the first direction D1.

[0055] When viewed from the first direction D1, the exterior body 40 includes (four here) corners 40c that face the module corners 1c of the energy storage module 1. The corners 40c are chamfered, for example, in a C-shape.

[0056] Here, when viewed from the first direction D1, the first laminating member 91 and the second laminating member 92 are each formed into a rectangular frame shape as viewed from the first direction D1 by integrating multiple parts including a pair of first portions 81 and second portions 82, 83. When viewed from the first direction D1, a portion of the first portion 81 overlaps a portion of the second portion 82, and another portion of the first portion 81 overlaps the second portion 83. The first portion 81 is formed linearly as viewed from the first direction D1, and the second portions 82, 83 are formed U-shaped and facing each other as viewed from the first direction D1. The second portions 82 and 83 are arranged spaced apart from each other in the third direction D3 as viewed from the first direction D1, and the pair of first portions 81 are arranged parallel to each other so as to connect the second portions 82 and 82.

[0057] 2 and 6 , when viewed from a direction intersecting the first direction D1, the first laminate member 91 is joined to the first surface 31s of the first conductive plate 31. Furthermore, the second laminate member 92 is joined to the second surface 32s of the second conductive plate 32.

[0058] A first end 91p, which is the end opposite to the end joined to the first surface 31s of the first laminate member 91, and a second end 92p, which is the end opposite to the end joined to the second surface 32s of the second laminate member 92, are hermetically joined (e.g., welded) to each other on a side surface along the first direction D1 of the energy storage module 1 to form an end joint portion 90p. At the end joint portion 90p, an adhesive layer 93 of the first laminate member 91 and an adhesive layer 93 of the second laminate member 92 are joined. This ensures insulation between the first laminate member 91 and the second laminate member 92 (i.e., the first exterior portion 41 and the second exterior portion 42).

[0059] As described above, the width W42 of the second flange portion 42f formed by the second laminating member 92 is greater than the width W41 of the first flange portion 41f formed by the first laminating member 91. The first end portion 91p of the first laminating member 91 is an end portion including the outer edge of the first flange portion 41f, and the second end portion 92p of the second laminating member 92 is an end portion including the outer edge of the second flange portion 42f. Therefore, due to the difference between the width W41 of the first flange portion 41f and the width W42 of the second flange portion 42f, the first end surface 91s, which is the end surface of the first end portion 91p of the first laminating member 91, and the second end surface 92s, which is the end surface of the second end portion 92p of the second laminating member 92, are offset from each other. The end joint portion 90p is bent while maintaining the offset between the first end surface 91s and the second end surface 92s. Here, the end joint portion 90p has a first bent portion B1, a second bent portion B2, and a third bent portion B3.

[0060] This point will be described in more detail. As described above, the first flange portion 41f has four linear portions 411, 412, 413, and 414 when viewed from the first direction D1, and the second flange portion 42f has four linear portions 421, 422, 423, and 424 when viewed from the first direction D1. In the energy storage device 100, first, of the linear portions 411 to 414 and 421 to 424 of the first flange portion 41f and the second flange portion 42f, first linear portions L11 and L12 that face each other across the energy storage module 1 are bent. The first linear portion L11 is formed by the linear portion 411 and the linear portion 421, and the first linear portion L12 is formed by the linear portion 412 and the linear portion 422. The straight line portions 411 , 412 , 421 , and 422 are longer than the other straight line portions 413 , 423 , 414 , and 424 .

[0061] FIG. 7 is a schematic cross-sectional view showing an enlarged portion of FIG. 6 . While FIG. 7 shows the first linear portion L11 of the first linear portions L11, L12, the first linear portion L12 has a similar configuration. As shown in FIGS. 5 to 7 , the first linear portion L11 has a first bent portion B1 extending along the energy storage module 1 when viewed from the first direction. At the first bent portion B1, only the second flange portions 42f are bent at the first bent portion B1 so that the resin layers 95 of the second flange portions 42f face each other (i.e., inward). Here, the second flange portions 42f are bent 180 degrees at the first bent portion B1.

[0062] The first linear portion L11 has a second bent portion B2 and a third bent portion B2 that extend along the energy storage module 1 when viewed from the first direction D1. The first bent portion B1, the second bent portion B2, and the third bent portion B3 extend parallel to one another when viewed from the first direction D1. The first linear portion L11 is bent along the first direction D1 at the second bent portion B2 and the third bent portion B3 (i.e., the second bent portion B2 and the third bent portion B3, which are bent lines, extend along the energy storage module 1 when viewed from the first direction D1).

[0063] Here, in the first linear portion L11, both the first flange portion 41f and the second flange portion 42f are bent 180° at the second bend portion B2. Also, in the first linear portion L11, both the first flange portion 41f and the second flange portion 42f are bent 90° at the third bend portion B3 (in FIG. 7 , for convenience of illustration, they are shown as angles smaller than 90°). The bending directions in the first bend portion B1, the second bend portion B2, and the third bend portion B3 are all the same. Therefore, in this example, in the first linear portion L11, the first flange portion 41f is bent 270°, and the second flange portion 42f is bent 450°. For convenience of illustration, the bending portion B3 is positioned away from the base of the first flange portion 41f and the second flange portion 42f (the boundary between the first recess 41p and the second recess 42p), but it may also be located at the base of the first flange portion 41f and the second flange portion 42f.

[0064] In the illustrated example, at the third bent portion B3 closest to the energy storage module 1 (the first recess 41 p and the second recess 42 p), the first flange portion 41 f and the second flange portion 42 f are bent downward (here, the direction from the positive electrode terminal electrode 13 toward the negative electrode terminal electrode 12, that is, the negative direction of the first direction D1) so that the first flange portion 41 f is located outward (opposite the energy storage module 1) than the second flange portion 42 f. Also, at the second bent portion B2 next closest to the energy storage module 1 after the third bent portion B3, the first flange portion 41 f and the second flange portion 42 f are bent in the direction opposite to the bending direction of the third bent portion B3, i.e., upward (here, the direction from the negative electrode terminal electrode 12 toward the positive electrode terminal electrode 13, that is, the positive direction of the first direction D1) so that the first flange portion 41 f is located outward than the second flange portion 42 f.

[0065] Furthermore, at the first bent portion B1 that is farthest from the energy storage module 1, only the second flange portion 42f is bent downward in the same direction as the bending direction of the third bent portion B3, i.e., the opposite direction to the bending direction of the second bent portion B2, and so that the second flange portions 42f face each other. That is, in the illustrated example, the bending direction is alternately changed in the order of the third bent portion B3, the second bent portion B2, and the first bent portion B1, while maintaining the inner and outer positional relationship between the first flange portion 41f and the second flange portion 42f.

[0066] In the illustrated example, when viewed from a direction intersecting the first direction D1 (e.g., the third direction D3), the first end surface 91s of the first flange portion 41f and the second end surface 92s of the second flange portion 42f are located between the second bent portion B2 and the third bent portion B3. In particular, when viewed from a direction intersecting the first direction D1, the first flange portion 41f is located closer to the second end surface 92s (toward the energy storage module 1) and terminates closer to the first bent portion B1. The first end surface 91s is located between the first bent portion B1 and the second bent portion B2. Furthermore, in this example, the first bent portion B1 is located between the second bent portion B2 and the third bent portion B3 when viewed from a direction intersecting the first direction D1.

[0067] Meanwhile, among the linear portions 411 to 414 and 421 to 424 of the first flange portion 41f and the second flange portion 42f, a second linear portion L2, which is different from the first linear portions L11 and L12 that face each other across the energy storage module 1, is also bent. The second linear portion L2 is, for example, a linear portion formed by linear portions 413 and 423, or a linear portion formed by linear portions 414 and 424. The second linear portion L2 has a fourth bent portion B4 that extends along the energy storage module 1 when viewed from the first direction D1. In the second linear portion L2, both the first flange portion 41f and the second flange portion 42f are bent 90 degrees at the fourth bent portion B4.

[0068] Note that, when the second straight portion L2 is a portion where an extracting portion of the wiring DL including a voltage detection line or the like extending from the electrode stack 10 is formed, the second straight portion L2 does not have to have the fourth bent portion B4. Furthermore, when the second straight portion L2 is not a portion where an extracting portion of the wiring DL including a voltage detection line or the like extending from the electrode stack 10 is formed, the second straight portion L2 may have an additional bent portion in addition to the fourth bent portion B4.

[0069] 5 and 6 , the first laminate member 91 is formed in a rectangular frame shape surrounding the outer edge of the first conductive plate 31 when viewed from the first direction D1 and is joined to the first surface 31s of the first conductive plate 31 via an adhesive layer 93. The first laminate member 91 has a joint 96 with the first conductive plate 31, and an end surface 91r of the first laminate member 91 on the joint 96 side is covered with a first insulating material 61. The first insulating material 61 includes an outer portion A1 joined to the resin layer 95 of the first laminate member 91 and an inner portion A2 joined to the first conductive plate 31. The first insulating material 61 is composed of a resin compatible with the adhesive layer 93 and the resin layer 95 of the first laminate member 91. The first insulating material 61 covers the end surface (part of the end surface 91r) of the metal layer 94 on the joint 96 side.

[0070] Additionally, a second insulating material 62 made of an acid-modified resin compatible with the adhesive layer 93 is interposed between the adhesive layer 93 of the first laminate member 91 and the first conductive plate 31 in the first direction D1. The second insulating material 62 extends inward from the end surface 91r of the first laminate member 91 and is also interposed between the first insulating material 61 and the first conductive plate 31. Therefore, the first laminate member 91 and the first insulating material 61 are joined to the first conductive plate 31 via the second insulating material 62. The inner portion A2 of the first insulating material 61 is welded to the second insulating material 62. The first insulating material 61 and the second insulating material 62 are made of resins compatible with each other. For example, the first insulating material 61 is made of an acid-modified resin, and the first conductive plate 31 is made of a metal. The first insulating material 61 and the second insulating material 62 are made of, for example, an acid-modified polyolefin resin.

[0071] The same applies to the second laminate member 92. That is, the second laminate member 92 is provided in a rectangular frame shape surrounding the outer edge of the second conductive plate 32 when viewed from the first direction D1 and is joined to the second surface 32s of the second conductive plate 32 via an adhesive layer 93. The second laminate member 92 has a joint 97 with the second conductive plate 32, and an end surface 92r of the second laminate member on the joint 97 side is covered with a first insulating material 61. The first insulating material 61 includes an outer portion joined to the resin layer 95 of the second laminate member 92 and an inner portion joined to the second conductive plate 32. The first insulating material 61 is composed of a resin compatible with the adhesive layer 93 and resin layer 95 of the second laminate member 92. The first insulating material 61 covers the end surface (part of the end surface 92r) of the metal layer 94 on the joint 97 side. When the first insulating material 61 is welded to the adhesive layer 93 , the end surface of the metal layer 94 may be covered with the resin of the adhesive layer 93 .

[0072] Furthermore, a second insulating material 62 made of an acid-modified resin compatible with the adhesive layer 93 is interposed between the adhesive layer 93 of the second laminate member 92 and the second conductive plate 32 in the first direction D1. The second insulating material 62 extends inward from an end surface 92r of the second laminate member 92 and is also interposed between the first insulating material 61 and the second conductive plate 32. Therefore, the second laminate member 92 and the first insulating material 61 are joined to the second conductive plate 32 via the second insulating material 62. An inner portion of the first insulating material 61 is welded to the second insulating material 62.

[0073] FIG. 8 is a schematic plan view of the energy storage device shown in FIG. 1 , showing the exterior body through a see-through view and adding insulating material. As shown in FIG. 8 , the second insulating material 62 includes a frame-shaped portion 63 overlapping the first conductive plate 31 and multiple (here, four) protruding portions 64 protruding outward from the frame-shaped portion 63 when viewed from the first direction D1. Here, the first conductive plate 31 is rectangular, and the frame-shaped portion 63 is rectangular. When viewed from the first direction D1, in the first exterior portion 41, one end of the first portion 81 and one end of the second portion 82 of the first laminate member 91 overlap the protruding portions 64. Furthermore, the first portion 81 and the second portion 82 overlap at the protruding portions 64 to form a first overlapping region C1. When viewed from the first direction D1, the other end of the first portion 81 and the end of the second portion 83 of the first laminating member 91 overlap with another protruding portion 64. Furthermore, the first portion 81 and the second portion 83 are overlapped at the other protruding portion 64 to form a first overlapping region C2.

[0074] The first portion 81 and the second portion 82 of the first laminate member 91 are integrated in a first overlapping region C1 where they overlap each other as viewed from the first direction D1 by welding the resin layer 95 of the first portion 81 to the adhesive layer 93 of the second portion 82. The adhesive layer 93 of the first portion 81 of the first laminate member 91 is also joined to the protruding portion 64 in the region where it overlaps with the protruding portion 64. Therefore, the protruding portion 64 is interposed between the end face of the first portion 81 of the first laminate member 91 on the protruding portion 64 side and the first conductive plate 31.

[0075] The second exterior portion 42 is similarly configured. That is, when viewed from the first direction D1, in the second exterior portion 42, one end of the first portion 81 and one end of the second portion 82 of the second laminate member 92 overlap the protruding portion 64. The first portion 81 and the second portion 82 of the second laminate member 92 overlap at the protruding portion 64 to form a second overlapping region C3. When viewed from the first direction D1, the other end of the first portion 81 and one end of the second portion 83 of the second laminate member 92 overlap at another protruding portion 64. The first portion 81 and the second portion 83 of the second laminate member 92 overlap at another protruding portion 64 to form a second overlapping region C4. The frame portion 63 is joined to the first conductive plate 31 and the second conductive plate 32.

[0076] The first portion 81 and the second portion 82 of the second laminate member 92 are integrated in a second overlapping region C3 where they overlap each other as viewed in the first direction D1 by welding the resin layer 95 of the first portion 81 to the adhesive layer 93 of the second portion 82. The adhesive layer 93 of the first portion 81 of the second laminate member 92 is also joined to the protruding portion 64 in the region where it overlaps with the protruding portion 64. Therefore, the protruding portion 64 is interposed between the end face of the first portion 81 of the second laminate member 92 on the protruding portion 64 side and the second conductive plate 32.

[0077] Next, an example of a method for manufacturing the above-described energy storage device 100 will be described. FIGS. 9 to 12 are schematic plan views illustrating a step of the energy storage device manufacturing method according to this embodiment. In this method, first, as shown in FIG. 9A, a first exterior member 41A that forms the first exterior section 41 constituting the exterior body 40 and a second exterior member 42A that forms the second exterior section 42 are prepared (step S101: preparation step). Note that, in the illustrated example, for convenience, the first exterior member 41A and the second exterior member 42A are illustrated overlapping (identical), but they may actually be arranged overlapping or separately.

[0078] Step S101 will be described in more detail. In step S101, first, one first portion 81 and one second portion 82, 83 are joined together to form a first laminate member 91 (i.e., the first laminate member 91 is prepared). In step S101, another first portion 81 and another second portion 82, 83 are joined together to form a second laminate member 92 (i.e., the second laminate member 92 is prepared). In step S101, a first conductive plate 31 and a second conductive plate 32 are prepared.

[0079] Then, in step S101, a first exterior member 41A is constructed by providing (joining) a first laminate member 91 to the outer edge of the first conductive plate 31 when viewed from a direction intersecting the plate surface of the first conductive plate 31 (here, first direction D1) (first preparation step). Also, in step S101, a second laminate member 92 is provided to the outer edge of the second conductive plate 32 when viewed from a direction intersecting the plate surface of the second conductive plate 32 (here, first direction D1) (second preparation step).

[0080] 9B, in a subsequent step, for example, a processing (embossing) is performed on the flat plate-shaped first exterior member 41A, such as by pressing a mold against the first exterior member 41A, to form a rectangular parallelepiped-shaped (recessed into a rectangular parallelepiped) first recess 41p for accommodating the energy storage module 1 and a rectangular frame-shaped first flange portion 41f surrounding the first recess 41p (step S102: preparation step). The first recess 41p is formed in an area that includes the first opening 41h. That is, the first opening 41h is formed in the bottom surface of the first recess 41p.

[0081] Furthermore, using a similar technique, a rectangular parallelepiped second recess 42p for accommodating the energy storage module 1 and a rectangular frame-shaped second flange portion 42f surrounding the second recess 42p are formed in the second exterior member 42A (step S103: preparation step). The second recess 42p is formed in an area that includes the second opening 42h. That is, the second opening 42h is formed in the bottom surface of the second recess 42p. The order of steps S102 and S103 described above does not matter, and they may be performed sequentially or simultaneously.

[0082] Next, as shown in Figures 10(a) and 10(b), the outer periphery of the first flange portion 41f is cut to form a first outer edge 41e (step S104: cutting step). Figure 10(a) shows the state before cutting, and Figure 10(b) shows the state after cutting. In step S104, linear cuts are made parallel to each side in portions corresponding to the four sides of the rectangular outer periphery of the first flange portion 41f. Also, in step S104, the cuts are made so that the exterior corners 41c of the first flange portion 41f that face the module corners 1c when the energy storage module 1 is placed in the first recess 41p are chamfered (in a C-shaped manner in the illustrated example).

[0083] The outer periphery of the second flange portion 42f is cut to form a second outer edge 42e (step S105: cutting step). In step S105, linear cuts are made parallel to the four sides of the rectangular outer periphery of the second flange portion 42f. In step S105, the cuts are made so as to chamfer (in the illustrated example, C-shaped) the exterior corners 42c of the second flange portion 42f that face the module corners 1c when the energy storage module 1 is placed in the second recess 42p. Figure 8(b) schematically illustrates the state after cutting. After steps S104 and S105, the first exterior member 41A and the second exterior member 42A are formed into rectangular frame shapes with the four exterior corners 41c, 42c chamfered.

[0084] In steps S104 and S105, the outer peripheries of the first flange portion 41f and the second flange portion 42f are cut so that the second outer edge 4e is positioned outward from the first outer edge 41e when viewed from the first direction D1, with the first flange portion 41f and the second flange portion 42f overlapping each other to be joined in step S107 (described later). In other words, in steps S104 and S105, the outer peripheries of the first flange portion 41f and the second flange portion 42f are cut so that the width W42 of the second flange portion 42f, which is the distance from the outer edge of the second recess 42p to the second outer edge 42e, is greater than the width W41 of the first flange portion 41f, which is the distance from the outer edge of the first recess 41p to the first outer edge 41e, as shown in FIG.

[0085] 11A, step S106 (accommodating step) is performed to accommodate the energy storage module 1 (and the cover member 50) in the first recess 41p and the second recess 42p, and to overlap the first flange portion 41f and the second flange portion 42f. As described above, in steps S104 and S105, the outer peripheries of the first flange portion 41f and the second flange portion 42f are cut so that the first outer edge 41e (first end surface 91s of the first laminate member 91) of the first flange portion 41f and the second outer edge 42e (second end surface 92s of the second laminate member 92) of the second flange portion 42f are misaligned from each other over the entire circumference of the first flange portion 41f and the second flange portion 42f when the first flange portion 41f and the second flange portion 42f are overlapped. In this embodiment, the first exterior member 41A is cut so that it is smaller than the second exterior member 42A. Therefore, in step S106, when the first flange portion 41f and the second flange portion 42f are overlapped with each other, the second outer edge 4e is positioned outward from the first outer edge 41e as viewed from the first direction D1.

[0086] Thereafter, as described above, the energy storage module 1 is accommodated in the first recess 41 p and the second recess 42 p, and the first flange portion 41 f and the second flange portion 42 f are overlapped (step S106: accommodation step). In particular, in step S106, the energy storage module 1 is positioned so that the current collector 15 of the positive terminal electrode 13 located at one end of the energy storage module 1 in the first direction D1 contacts the first conductive plate 31, and the current collector 15 of the negative terminal electrode 12 located at the other end of the energy storage module 1 in the first direction D1 contacts the second conductive plate 32.

[0087] 11(b) and 12, the first flange portion 41f and the second flange portion 42f are joined (welded) to each other at the overlapping portions, thereby integrating the first exterior member 41A and the second exterior member 42A while insulating them from each other to form the exterior body 40 (step S107: joining step). In particular, in step S107, the first flange portion 41f and the second flange portion 42f are joined to each other in a state in which the first outer edge 41e of the first flange portion 41f and the second outer edge 42e of the second flange portion 42f are shifted from each other.

[0088] Specifically, in step S107, the first flange portion 41 f and the second flange portion 42 f are heat-pressed into a rectangular frame shape to conform to the shapes of the first flange portion 41 f and the second flange portion 42 f as viewed from the first direction D1, i.e., in the peripheral region R1 including the overlapping portions of the first flange portion 41 f and the second flange portion 42 f, thereby joining (welding) the first flange portion 41 f and the second flange portion 42 f. At the same time, in step S107, corner regions R2 located inside the corners of the peripheral region R1 as viewed from the first direction D1 are heat-pressed to join (weld) the first flange portion 41 f and the second flange portion 42 f. Therefore, in the finished product, the first exterior portion 41 and the second exterior portion 42 are also joined to each other by bonding adhesive layers 93 in the rectangular frame-shaped peripheral region R1 of the first flange portion 41 f and the second flange portion 42 f and in the corner regions R2 located inside the corners of the peripheral region R1.

[0089] 12, the first flange portion 41f and the second flange portion 42f that are joined together are bent while maintaining the misalignment between the first outer edge 41e of the first flange portion 41f and the second outer edge 42e of the second flange portion 42f (step S108: bending step). In the present embodiment, as an example, as shown in FIG. 5, among the four linear portions 411 to 414 and 421 to 424 of the first flange portion 41f and the second flange portion 42f, bending is performed at first linear portions L11 and L12 that face each other across the energy storage module 1 and one second linear portion L2 that is different from the first linear portions L11 and L12 that face each other across the energy storage module 1.

[0090] 12 illustrates a third bending portion B3 of the first linear portions L11 and L12 and a fourth bending portion B4 of the second linear portion L2. In step S108, the first flange portion 41 f and the second flange portion 42 f are bent at the second bending portion B2 and the third bending portion B3 of the first linear portions L11 and L12, and only the second flange portion 42 f is further bent at the first bending portion B1 to obtain the state shown in FIG.

[0091] The third bending portion B3 is one bending portion that extends along the energy storage module 1 when viewed from the first direction D1, and the fourth bending portion B4 is another bending portion that extends along the energy storage module 1 when viewed from the first direction D1 and in a direction that intersects with the third bending portion B3. Then, in step S108, the first flange portion 41 f and the second flange portion 42 f are bent at the third bending portion B3 and the fourth bending portion B4, but the first flange portion 41 f is not bent at the intersection where the third bending portion B3 and the fourth bending portion B4 intersect.

[0092] As described above, the first exterior member 41A and the second exterior member 42A constitute the exterior body 40 (the first exterior part 41 and the second exterior part 42) that covers the energy storage module 1. After that, insulation is performed using the first insulating material 61, thereby obtaining the energy storage device 100 shown in FIG. 2 and the like.

[0093] As described above, in the energy storage device manufacturing method according to the present embodiment, the energy storage device 100 is manufactured by providing the exterior body 40 on the energy storage module 1. To this end, first, a first exterior member 41A and a second exterior member 42A are prepared, each including a metal layer 94 that forms the exterior body 40. Next, a first recess 41p for accommodating the energy storage module 1 and a rectangular frame-shaped first flange portion 41f that surrounds the first recess 41p are formed in the first exterior member 41A.

[0094] Similarly, a second recess 42p and a second flange 42f are formed in the second exterior member 42A. Next, the outer periphery of the first flange 41f is cut to form the first outer edge 41e, and the outer periphery of the second flange 42f is cut to form the second outer edge 42e. The energy storage module 1 is then housed in the first recess 41p and the second recess 42p, and the first flange 41f and the second flange 42f are overlapped and joined to each other. This integrates the first exterior member 41A and the second exterior member 42A, forming the exterior body 40 that houses the energy storage module 1 therein.

[0095] In the energy storage device manufacturing method according to the present embodiment, as described above, before the first flange portion 41 f and the second flange portion 42 f are overlapped and joined, the outer peripheries of the first flange portion 41 f and the second flange portion 42 f are cut to form the first outer edge 41 e of the first flange portion 41 f and the second outer edge 42 e of the second flange portion 42 f. Therefore, when the first flange portion 41 f and the second flange portion 42 f are overlapped with each other, the outer peripheries of the first flange portion 41 f and the second flange portion 42 f can be cut so that the second outer edge 42 e is positioned outward of the first outer edge 41 e when viewed from the first direction D1. As a result, when the first flange portion 41f and the second flange portion 42f are joined in a later process, the first end face 91s (of the first laminate member 91), which is the end face of the first outer edge 41e of the first flange portion 41f, and the second end face 92s (of the second laminate member 92), which is the end face of the second outer edge 42e of the second flange portion, are offset from each other. This ensures that the metal layer 94 on the first end face 91s and the metal layer 94 on the second end face 92s are spaced apart from each other, ensuring an insulating distance. This prevents short circuits through the exterior body 40.

[0096] Furthermore, the energy storage device manufacturing method according to this embodiment includes, after step S107 (joining step), step S108 (bending step) in which the joined first flange portion 41 f and second flange portion 42 f are bent. Furthermore, in steps S104 and S105 (cutting steps), corners (exterior corners 41 c) of the first flange portion 41 f and corners (exterior corners 42 c) of the second flange portion 42 f, which were formed into a rectangular frame shape in step S101 (preparing step), are cut. In this way, bending the first flange portion 41 f and the second flange portion 42 f saves space, while preventing wrinkles from forming at the corners when the first flange portion 41 f and the second flange portion 42 f are bent.

[0097] Furthermore, in the energy storage device manufacturing method according to this embodiment, step S107 includes a step of hot-pressing a peripheral region R1 including an overlapping portion of the first flange portion 41 f and the second flange portion 42 f as viewed from the first direction D1 into a rectangular frame shape to join the first flange portion 41 f and the second flange portion 42 f (first joining step), and a step of hot-pressing a corner region R2 located inside a corner of the peripheral region R1 as viewed from the first direction D1 to join the first flange portion 41 f and the second flange portion 42 f (second joining step). This improves sealing performance.

[0098] In the energy storage device manufacturing method according to the present embodiment, in step S108 (bending step), the first flange portion 41 f and the second flange portion 42 f are bent so that the second flange portion 42 f is bent to the side opposite the first flange portion 41 f. This separates the outer edge of the second flange portion 42 f from the outer edge of the first flange portion 41 f, thereby improving insulation.

[0099] Furthermore, in the energy storage device manufacturing method according to this embodiment, in step S108 (bending step), the first flange portion 41f and the second flange portion 42f are bent at one bending portion (third bending portion B3) that is aligned with the energy storage module 1 when viewed from the first direction D1, and at another bending portion (fourth bending portion B4) that is aligned with the energy storage module 1 when viewed from the first direction D1 and extends in a direction that intersects with the first bending portion, and it is not necessary to bend the first flange portion 41f at the intersection where the one bending portion and the other bending portion intersect.

[0100] Furthermore, in the energy storage device manufacturing method according to this embodiment, step S101 (preparation step) includes a first preparation step of preparing a first conductive plate 31 and a first laminate member 91, and providing the first laminate member 91 on the outer edge of the first conductive plate 31 when viewed in a direction intersecting the plate surface of the first conductive plate 31 (first direction D1), thereby forming a first exterior member 41A, and a second preparation step of preparing a second conductive plate 32 and a second laminate member 92, and providing the second laminate member 92 on the outer edge of the second conductive plate 32 when viewed in a direction intersecting the plate surface of the second conductive plate 32 (first direction D1), thereby forming a second exterior member 42A. Then, in step S106 (accommodating step), the energy storage module 1 is arranged so that the current collector 15 of the electrode located at one end of the energy storage module in the first direction D1 contacts the first conductive plate 31, and the current collector 15 of the electrode located at the other end of the energy storage module 1 in the first direction D1 contacts the second conductive plate 32. This allows current to be extracted from a large area by the first conductive plate 31 and the second conductive plate 32, thereby improving output.

[0101] Furthermore, in the energy storage device manufacturing method according to this embodiment, the first laminate member 91 is made up of one first portion 81 and one second portion 82, 83, and the second laminate member 92 is made up of another first portion 81 and another second portion 82, 83. In the first preparation step, the frame-shaped first laminate member 91 is formed by joining the one first portion 81 and the one second portion 82, 83, and in the second preparation step, the frame-shaped second laminate member 92 is formed by joining the other first portion 81 and the other second portion 82, 83. Therefore, the frame-shaped first laminate member 91 and second laminate member 92 can be easily formed.

[0102] The above embodiment has described one aspect of the method for manufacturing an energy storage device according to the present disclosure. Therefore, the method for manufacturing an energy storage device according to the present disclosure can be any modification of the above-described method. Next, modifications will be described.

[0103] Fig. 13 is a plan view showing a first exterior member and a second exterior member according to a modified example. Fig. 14 is a plan view showing the first exterior member and the second exterior member shown in Fig. 13 overlapped with each other. In the first preparation step and the second preparation step, as shown in Figs. 13 and 14, when the first flange portion 41f and the second flange portion 42f are overlapped in the first direction D1 in step S106 (accommodating step), the first portion 81 and the second portions 82 and 83 may be joined such that the joints (first overlapping regions C1 and C2) between the first portion 81 and the second portions 82 and 83 of the first exterior member 41A (first laminate member 91) and the joints (second overlapping regions C3 and C4) between the first portion 81 and the second portions 82 and 83 of the second exterior member 42A (second laminate member 92) do not overlap with each other in the first direction D1.

[0104] In the illustrated example, one of a pair of first overlapping regions C1 that face each other across the first conductive plate 31 of the first exterior member 41A, and one of a pair of second overlapping regions C3 that face each other across the second conductive plate 32 of the second exterior member 42A, which is located on the same side as the one first overlapping region C1 when the first exterior member 41A and the second exterior member 42A are overlapped, are offset by a predetermined offset amount OA.

[0105] In addition, one of a pair of first overlapping regions C2 that face each other across the first conductive plate 31 of the first exterior member 41A and one of a pair of second overlapping regions C4 that face each other across the second conductive plate 32 of the second exterior member 42A, which is located on the same side as the one first overlapping region C2 when the first exterior member 41A and the second exterior member 42A are overlapped, are similarly offset.

[0106] This ensures that when the first flange portion 41f and the second flange portion 42f are overlapped, the first overlapping regions C1 and C2 of the first exterior member 41A and the second overlapping regions C3 and C4 of the first portion 81 and the second portion 82 and 83 of the second exterior member 42A do not overlap with each other when viewed from the first direction D1. In this case, the first flange portion 41f and the second flange portion 42f are easily folded in step S108 (bending step). In this case, the first overlapping regions C1 and C2 and the second overlapping regions C3 and C4 of the first exterior portion 41 and the second exterior portion 42 also do not overlap with each other when viewed from the first direction D1.

[0107] In the above embodiment, the first flange portion 41f and the second flange portion 42f are bent at three bends, i.e., the first bend B1, the second bend B2, and the third bend B3, at the first linear portions L11 and L12, which are two linear portions facing each other across the four linear portions 411 to 414 and 421 to 424 of the energy storage module 1. However, as shown in FIG. 15 , the first linear portions L11 and L12 may have only the second bend B2 and the third bend B3. That is, the first flange portion 41f and the second flange portion 42f may be bent twice at the first linear portions L11 and L12. Furthermore, as shown in FIG. 16 , the first linear portions L11 and L12 may have only the third bend B3. That is, the first flange portion 41f and the second flange portion 42f may be bent once at the first linear portions L11 and L12.

[0108] As described above, among the linear portions 411-414 and 421-424 of the first flange portion 41f and the second flange portion 42f, the second linear portion L2, which is different from the first linear portions L11 and L12 that face each other across the energy storage module 1, may be bent twice or once as shown in FIGS. 15 and 16. Furthermore, any portion of the first flange portion 41f and the second flange portion 42f may be bent four or more times. In either case, the width W42 of the second flange portion 42f is larger than the width W1 of the first flange portion 41f, so that the first end surface 91s and the second end surface 92s are offset, thereby ensuring insulation between the metal layers 94 at each end surface.

[0109] Furthermore, the first insulating material 61 and / or the second insulating material 62 may be omitted from the energy storage device 100. Even if the first insulating material 61 and / or the second insulating material 62 are not omitted, the first insulating material 61 and the second insulating material 62 may be configured as a single resin part.

[0110] In the energy storage device manufacturing method, the cover member 50 may be omitted from the energy storage module 1 on which the exterior body 40 is provided. In step S107, the exterior corners 41 c, 42 c of the first flange 41 f and the second flange 42 f do not have to be cut to match the chamfered shape of the module corner 1 c. Furthermore, in the energy storage device manufacturing method, step S108 of bending the first flange 41 f and the second flange 42 f may be omitted.

[0111] FIG. 17 is a schematic cross-sectional view showing a bending portion according to a modified example. In the example shown in FIG. 17 , the relative relationship between the first bending portion B1, the second bending portion B2, and the third bending portion B3 is the same as in the example shown in FIG. 7 . Meanwhile, as shown in FIG. 17 , the first flange portion 41f extends beyond the first bending portion B1 when viewed from a direction intersecting the first direction D1 and terminates before the second end surface 92s (toward the energy storage module 1). In this case, the first flange portion 41f is bent downward at the first bending portion B1 together with the second flange portion 42f. At this time, the first bending portion B1 is bent so that the first flange portion 41f is positioned outward of the second flange portion 42f. The first end surface 91s of the first flange portion 41f is located between the first bending portion B1 and the second bending portion B2. In particular, in this case, the first end surface 91s is located between the first bent portion B1 and the second end surface 92s.

[0112] FIG. 18 is a schematic cross-sectional view showing a bending portion according to a modified example. FIG. 18 illustrates an end joint portion 90p of the first linear portion L12 opposite the first linear portion L11 illustrated in FIG. 17 , but the same applies to the first linear portion L11. In the example shown in FIG. 18 , at the third bending portion B3 closest to the energy storage module 1, the first flange portion 41f and the second flange portion 42f are bent downward so that the first flange portion 41f is located outward relative to the second flange portion 42f. At the second bending portion B2 next closest to the energy storage module 1 after the third bending portion B3, the first flange portion 41f and the second flange portion 42f are bent upward in the opposite direction to the bending direction of the third bending portion B3, i.e., so that the first flange portion 41f is located inward (toward the energy storage module 1) relative to the second flange portion 42f. As a result, the first flange portions 41f face each other at the second bending portion B2.

[0113] Furthermore, at the first bending portion B1 that is farthest from the energy storage module 1, the first flange portion 41 f and the second flange portion 42 f are bent downward in the opposite direction to the bending direction of the second bending portion B2, and so that the first flange portion 41 f is more inward than the second flange portion 42 f (in other words, so that the first flange portions 41 f face each other). In other words, in the example of FIG. 18 , the inner and outer positional relationship of the first flange portion 41 f and the second flange portion 42 f is different between the first bending portion B1 and the second bending portion B2 and the third bending portion, and the bending direction is alternately different in the order of the third bending portion B3, the second bending portion B2, and the first bending portion B1.

[0114] 18 , when viewed in a direction intersecting the first direction D1 (e.g., the third direction D3), the second flange portion 42f is located closer to the power storage module 1 than the first end surface 91s of the first flange portion 41f and terminates closer to the first end surface 91s than the first bent portion B1. As a result, the second end surface 92s of the second flange portion 42f is located between the first end surface 91s and the first bent portion B1 when viewed in a direction intersecting the first direction D1. Furthermore, the first end surface 91s of the first flange portion 41f and the second end surface 92s of the second flange portion 42f are located between the first bent portion B1 and the second bent portion B2.

[0115] In particular, the first end surface 91s of the first flange portion 41f is located lower than the third bent portion B3 (closer to the second bent portion B2) when viewed from a direction intersecting the first direction D1, and the second end surface 92s of the second flange portion 42f is located at approximately the same position as the third bent portion B3 or lower than the third bent portion B3 (closer to the second bent portion B2) when viewed from a direction intersecting the first direction D1.

[0116] The following additional notes will be made regarding the above embodiment.

[0117] The energy storage device manufacturing method according to the appendix is ​​[1] "a method for manufacturing an energy storage device including an energy storage module including a plurality of electrodes stacked along a first direction, and an exterior body including a first exterior member including a metal layer and a second exterior member including a metal layer, and accommodating the energy storage module therein, the method including a preparation step of forming, in the first exterior member, a first recess for accommodating the energy storage module and a first flange portion having a rectangular frame shape surrounding the first recess, and forming, in the second exterior member, a second recess for accommodating the energy storage module and a second flange portion having a rectangular frame shape surrounding the second recess; a cutting step of cutting an outer periphery of the first flange portion to form a first outer edge and cutting an outer periphery of the second flange portion to form a second outer edge; and and a joining step of joining an adhesive layer of the first flange portion and an adhesive layer of the second flange portion at the overlapping portion of the first flange portion and the second flange portion to integrate the first exterior member and the second exterior member to form the exterior body, wherein in the cutting step, in a state in which the first flange portion and the second flange portion joined in the joining step are overlapping each other, an outer periphery of the first flange portion and an outer periphery of the second flange portion are cut so that the second outer edge is positioned outside the first outer edge when viewed from the first direction.

[0118] The storage device manufacturing method according to the appendix may be [2] "the storage device manufacturing method described in [1] above, which includes a bending step of bending the first flange portion and the second flange portion joined to each other, and in the cutting step, cutting corners of the first flange portion and the second flange portion formed into a rectangular frame shape in the preparation step."

[0119] The manufacturing method for an electric storage device according to the appendix may be [3] "the manufacturing method for an electric storage device described in [1] or [2] above, wherein the joining step includes: a first joining step of hot-pressing a peripheral region including an overlapping portion of the first flange portion and the second flange portion as viewed from the first direction into a rectangular frame shape to join the first flange portion and the second flange portion; and a second joining step of hot-pressing a corner region located inside a corner of the peripheral region as viewed from the first direction to join the first flange portion and the second flange portion."

[0120] The storage device manufacturing method according to the appendix may be [4] "the storage device manufacturing method described in [2] above, in which, in the bending process, the first flange portion and the second flange portion are bent so that the second flange portion is bent in the opposite direction to the first flange portion."

[0121] The manufacturing method for an energy storage device according to the appendix may be [5] "the manufacturing method for an energy storage device described in [2] or [4] above, wherein in the bending step, the first flange portion and the second flange portion are bent at one bending portion that follows the energy storage module when viewed from the first direction, and another bending portion that follows the energy storage module when viewed from the first direction and extends in a direction intersecting the one bending portion, and the first flange portion is not bent at an intersection where the one bending portion and the other bending portion intersect."

[0122] The energy storage device manufacturing method according to the appendix may be [6] "the energy storage device manufacturing method according to any one of [1] to [5] above, wherein the preparation step includes: a first preparation step of preparing a first conductive plate and a first laminate member, and providing the first laminate member on an outer edge of the first conductive plate when viewed in a direction intersecting with a plate surface of the first conductive plate, thereby constituting the first exterior member; and a second preparation step of preparing a second conductive plate and a second laminate member, and providing the second laminate member on the outer edge of the second conductive plate when viewed in a direction intersecting with a plate surface of the second conductive plate, thereby constituting the second exterior member; and in the accommodating step, the energy storage module is arranged such that a current collector of the electrode located at one end of the energy storage module in the first direction contacts the first conductive plate, and a current collector of the electrode located at the other end of the energy storage module in the first direction contacts the second conductive plate."

[0123] The manufacturing method for an electric storage device according to the appendix may be [7] "the manufacturing method for an electric storage device described in the above [6], wherein the first laminate member is composed of a first part and a second part, the second laminate member is composed of another first part and another second part, the first preparation step forms a frame-shaped first laminate member by joining the one first part and the one second part, and the second preparation step forms a frame-shaped second laminate member by joining the other first part and the other second part."

[0124] The manufacturing method for an electric storage device according to the appendix may be [8] "the manufacturing method for an electric storage device described in [7] above, in which in the first preparation step and the second preparation step, the one first part and the one second part are joined, and the other first part and the other first part are joined, such that when the first flange portion and the second flange portion are overlapped in the first direction in the accommodation step, the joint between the one first part and the one second part and the joint between the other first part and the other second part do not overlap when viewed from the first direction."

[0125] REFERENCE SIGNS LIST 1...energy storage module, 10...electrode laminate, 20...sealing body, 31...first conductive plate, 31s...first surface, 32...second conductive plate, 32s...second surface, 40...exterior body, 41...first exterior part, 41A...first exterior member, 41p...first recess, 41f...first flange part, 41e...first outer edge, 42...second exterior part, 42A...second exterior member, 42p...second recess, 42f...second flange part, 42e...second outer edge, 50...cover member, 81...first part, 82...second part, 83...second part, 90p...end joint, 91...first laminate member, 91s...first end surface, 92...second laminate member, 92s...second end surface, 100...energy storage device.

Claims

1. A method for manufacturing an energy storage device including an energy storage module including a plurality of electrodes stacked along a first direction, and an exterior body including a first exterior member including a metal layer and a second exterior member including a metal layer, and housing the energy storage module therein, the method comprising: a preparation step of forming, in the first exterior member, a first recess for housing the energy storage module and a first flange portion having a rectangular frame shape surrounding the first recess, and forming, in the second exterior member, a second recess for housing the energy storage module and a second flange portion having a rectangular frame shape surrounding the second recess; a cutting step of cutting an outer periphery of the first flange portion to form a first outer edge, and cutting an outer periphery of the second flange portion to form a second outer edge; an accommodation step of housing the energy storage module in the first recess and the second recess, and overlapping the first flange portion and the second flange portion in the first direction; a joining process of integrating the first exterior member and the second exterior member to form the exterior body by joining an adhesive layer of the first flange portion and an adhesive layer of the second flange portion at a portion where the first flange portion and the second flange portion are overlapped with each other, wherein in the cutting process, with the first flange portion and the second flange portion joined in the joining process overlapped with each other, the outer periphery of the first flange portion and the outer periphery of the second flange portion are cut so that the second outer edge is positioned outside the first outer edge when viewed from the first direction.

2. The method for manufacturing an energy storage device according to claim 1, further comprising a bending step of bending the first flange portion and the second flange portion that are joined together, and wherein the cutting step cuts off corners of the first flange portion and the second flange portion that have been formed into a rectangular frame shape in the preparation step.

3. The method for manufacturing an energy storage device according to claim 1 or 2, wherein the joining step includes: a first joining step of joining the first flange portion and the second flange portion by heat-pressing a peripheral region including an overlapping portion of the first flange portion and the second flange portion into a rectangular frame shape, and a second joining step of heat-pressing a corner region located inside a corner of the peripheral region when viewed from the first direction, to join the first flange portion and the second flange portion.

4. The method for manufacturing an electric storage device according to claim 2, wherein in the bending step, the first flange portion and the second flange portion are bent so that the second flange portion is bent in a direction opposite to the first flange portion.

5. A method for manufacturing an energy storage device according to claim 2 or 4, wherein in the bending step, the first flange portion and the second flange portion are bent at one bending portion that is aligned with the energy storage module when viewed from the first direction, and at another bending portion that is aligned with the energy storage module when viewed from the first direction and extends in a direction that intersects with the one bending portion, and the first flange portion is not bent at an intersection where the one bending portion and the other bending portion intersect.

6. The method for manufacturing an electricity storage device according to any one of claims 1 to 5, wherein the preparation step includes: a first preparation step of preparing a first conductive plate and a first laminate member, and providing the first laminate member on the outer edge of the first conductive plate when viewed in a direction intersecting with the plate surface of the first conductive plate, thereby constituting the first exterior member; and a second preparation step of preparing a second conductive plate and a second laminate member, and providing the second laminate member on the outer edge of the second conductive plate when viewed in a direction intersecting with the plate surface of the second conductive plate, thereby constituting the second exterior member; and wherein the accommodation step arranges the electricity storage module so that a current collector of the electrode located at one end of the electricity storage module in the first direction contacts the first conductive plate, and a current collector of the electrode located at the other end of the electricity storage module in the first direction contacts the second conductive plate.

7. The method for manufacturing an energy storage device according to claim 6, wherein the first laminate member is composed of a first portion and a second portion, the second laminate member is composed of another first portion and another second portion, the first preparation step comprises joining the one first portion and the one second portion to form a frame-shaped first laminate member, and the second preparation step comprises joining the other first portion and the other second portion to form a frame-shaped second laminate member.

8. The method for manufacturing an energy storage device according to claim 7, wherein in the first preparation step and the second preparation step, the one first part and the one second part are joined, and the other first part and the other first part are joined, so that when the first flange part and the second flange part are overlapped in the first direction in the accommodation step, the joint between the one first part and the one second part and the joint between the other first part and the other second part do not overlap when viewed from the first direction.

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