Electric power storage module

Abstract

This electric power storage module comprises: an electrode laminate including current collectors and having a plurality of electrodes layered along a first direction; a first resin unit that forms an internal space between the current collectors adjacent in the first direction, and that is provided to the electrode laminate so as to seal the internal space; and a sealing body that is joined to the first resin unit. The outer surface of the first resin unit includes a first edge surface along the first direction, a second edge surface that opposes the first edge surface along the first direction, and four outer surfaces that extend along the first direction so as to connect the first edge surface and the second edge surface.

Description

Energy storage module

[0001] The present disclosure relates to an energy storage module.

[0002] Patent Document 1 describes a bipolar secondary battery. The power generating element of this bipolar secondary battery has multiple bipolar electrodes, each having a current collector on one side thereof and a current collector on the other side thereof, and an electrically coupled positive electrode active material layer on the other side thereof. The bipolar electrodes are stacked with an electrolyte layer interposed therebetween to form the power generating element. Adjacent positive electrode active material layers, electrolyte layers, and negative electrode active material layers constitute one cell layer. A seal portion is disposed on the outer periphery of the cell layer. The seal portion is disposed between the current collectors at the periphery of the current collectors to prevent contact between adjacent current collectors.

[0003] Patent No. 5504708

[0004] To improve the sealing performance of the seal portion of the bipolar secondary battery described above, it is possible to adopt a configuration in which a seal is attached to the seal portion that forms the outer surface of the laminate in which the electrodes are stacked. For example, when attaching a seal to the periphery of a communication hole (filling port) in the seal portion that connects the inside and outside of the bipolar secondary battery, an injection molding die or heat sealer is placed in the gripping area around the filling port of the seal portion, and the laminate is pressed in the stacking direction. In either case, by increasing the gripping area, the seal can be stably attached to the outer surface of the laminate.

[0005] An object of the present disclosure is to provide an energy storage module that can stably provide a sealing body that improves sealing performance.

[0006] The energy storage module according to the present disclosure includes an electrode stack having a plurality of electrodes including current collectors stacked along a first direction, a first resin part provided on the electrode stack to form an internal space between adjacent current collectors in the first direction and seal the internal space, and a sealing body joined to the first resin part, wherein the outer surface of the first resin part includes a first end face in the first direction, a second end face opposite to the first end face in the first direction, and four outer side faces extending along the first direction to connect the first end face and the second end face, the sealing body being joined to at least the first end face and the second end face, and the first resin part is formed of a plurality of frame-shaped sealing materials provided on peripheral edges of the plurality of current collectors and a plurality of frame-shaped seal materials interposed between adjacent seal materials in the first direction and forming an internal space between the current collectors together with the plurality of seal materials. and a spacer, a welded end portion formed by welding the outer peripheral edges of a plurality of sealing materials and a plurality of spacers opposite the internal space, the welded end portion including four outer surfaces, and a plurality of communication holes that open into a first outer surface, which is one of the four outer surfaces, and into the internal space, thereby connecting the internal space with the outside of the first resin portion, wherein, in at least a first portion including a region where the openings of the communication holes in the first outer surface of the first resin portion are formed, the inner edge of the sealing material is located inside the outer edge of the current collector when viewed from the first direction, and at least in the first portion, the inner edge of the sealing body coincides with the inner edge of the sealing material or is located outside the inner edge of the sealing material when viewed from the first direction, and at least in the first portion, at least a part of the inner edge of the spacer is located inside the inner edge of the sealing material when viewed from the first direction.

[0007] In this energy storage module, a first resin portion is provided on an electrode stack including electrodes stacked along a first direction, and a sealing body is bonded to a first end surface and a second end surface of the first resin portion in the first direction. In the first resin portion, a spacer is interposed between sealing materials provided on the peripheral portions of the current collectors of the electrodes. This forms an internal space between adjacent current collectors along the first direction by the sealing materials and the spacer. The first resin portion also has a plurality of communication holes formed therein, connecting a first outer surface of the first resin portion to the internal space. These communication holes can be used, for example, as injection ports for injecting electrolyte into the internal space. In a first portion including a region of the first outer surface of the first resin portion where the openings of the communication holes are formed, at least a portion of the inner edge of the spacer is positioned inside the inner edge of the sealing material when viewed from the first direction. Therefore, in at least this portion, the spacer is interposed beyond the inner edge of the sealing material when viewed from the first direction. Therefore, the part can be used as a gripping area, and a mold for injection molding, a heat sealer, or the like can be placed there, and a pressing force and gripping force can be applied to provide a sealing body, thereby enabling a stable provision of a sealing body that enhances sealing performance.

[0008] In the energy storage module according to the present disclosure, the four outer surfaces include three second outer surfaces that are different from the first outer surface, and in the second part including each of the three second outer surfaces in the first resin part, the inner edge of the spacer may be positioned more inward than the inner edge of the sealing material when viewed from the first direction.

[0009] In the energy storage module according to the present disclosure, the sealing body may include an injected resin portion welded to the first end surface and the second end surface in the first portion.

[0010] In the energy storage module according to the present disclosure, the sealing body may include a laminate sheet including a metal layer and an insulating layer laminated on the metal layer, and the laminate sheet may be welded to the first end surface and the second end surface.

[0011] In the energy storage module according to the present disclosure, the electrode stack includes a separator interposed between each of a plurality of electrodes adjacent in a first direction, and an end of the separator may be positioned between the sealing material and the spacer in the first direction.

[0012] According to the present disclosure, it is possible to provide an energy storage module in which a sealing body that improves sealing performance can be stably provided.

[0013] FIG. 1 is a schematic plan view of an energy storage module 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 cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a schematic cross-sectional view of a portion of the energy storage module shown in FIG. 3. FIG. 5 is a schematic view showing a portion of the energy storage module shown in FIG. 1. FIG. 6 is a schematic view showing a portion of the energy storage module shown in FIG. 1. FIG. 7 is a schematic cross-sectional view showing a modified example of the spacer shown in FIGS. 2 and 3. FIG. 8 is a schematic cross-sectional view of an energy storage module according to a modified example. FIG. 9 is a schematic cross-sectional view of an energy storage module according to another modified example.

[0014] An embodiment will be described below with reference to the drawings. In the description of the drawings, identical or equivalent elements will be designated by the same reference numerals, and redundant description will be omitted. In some cases, a Cartesian coordinate system defined by a coordinate axis indicating a first direction D1, a coordinate axis indicating a second direction D2, and a coordinate axis indicating a third direction D3 will be shown.

[0015] FIG. 1 is a schematic plan view of an energy storage module 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 cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a schematic cross-sectional view of a portion of the energy storage module shown in FIG. 3. The energy storage module 1 shown in FIGS. 1 to 4 is an energy storage module used in batteries for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The energy storage module 1 is a secondary battery such as a nickel-metal hydride secondary battery or a lithium-ion secondary battery. The energy storage module 1 may be an electric double layer capacitor or an all-solid-state battery. Here, the case where the energy storage module 1 is a lithium-ion secondary battery is shown.

[0016] The energy storage module 1 includes an electrode stack 10, a first resin portion 20, and a sealing body 50. The sealing body 50 is not shown in FIG. 1 . The electrode stack 10 includes a plurality of electrodes stacked along a first direction D1. The first direction D1 is the stacking direction of the electrodes, which is the height direction of the energy storage module 1. The plurality of electrodes includes a plurality of bipolar electrodes 11, a positive terminal electrode 12, and a negative terminal electrode 13. Separators 14 are interposed between adjacent electrodes.

[0017] The bipolar electrode 11 includes a current collector 15, a positive electrode active material layer 16, and a negative electrode active material layer 17. The current collector 15 has, for example, a rectangular sheet shape. The positive electrode active material layer 16 is provided on one surface 15a of the current collector 15. The negative electrode active material layer 17 is provided on the other surface 15b of the current collector 15. The multiple bipolar electrodes 11 are stacked such that the positive electrode active material layer 16 of one bipolar electrode 11 faces the negative electrode active material layer 17 of another bipolar electrode 11. Here, the one surface 15a of the current collector 15 faces one side of the first direction D1, and the other surface 15b of the current collector 15 faces the other side of the first direction D1.

[0018] 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 other words, in a plan view when 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.

[0019] The positive terminal electrode 12 has a current collector 15 and a positive electrode active material layer 16 provided on one surface 15a of the current collector 15. The positive terminal electrode 12 does not have the positive electrode active material layer 16 or the negative electrode active material layer 17 on the other surface 15b of the current collector 15. In other words, no active material layer is provided on the other surface 15b of the current collector 15 of the positive terminal electrode 12. The positive terminal electrode 12 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 12 is stacked on the bipolar electrode 11 so that the positive electrode active material layer 16 faces the negative electrode active material layer 17 of the bipolar electrode 11.

[0020] The negative electrode terminal electrode 13 has a current collector 15 and a negative electrode active material layer 17 provided on the other surface 15b of the current collector 15. The negative electrode terminal electrode 13 does not have a positive electrode active material layer 16 or a negative electrode active material layer 17 on one surface 15a of the current collector 15. In other words, no active material layer is provided on one surface 15a of the current collector 15 of the negative electrode terminal electrode 13. The negative electrode terminal electrode 13 is stacked on the bipolar electrode 11 at one end of the electrode laminate 10 in the first direction D1. The negative electrode terminal electrode 13 is stacked on the bipolar electrode 11 so that the negative electrode active material layer 17 faces the positive electrode active material layer 16 of the bipolar electrode 11.

[0021] The separators 14 are arranged so as to be sandwiched between adjacent bipolar electrodes 11, between the positive terminal electrode 12 and the bipolar electrode 11, and between the negative terminal electrode 13 and the bipolar electrode 11. The separators 14 are interposed between the positive electrode active material layer 16 and the negative electrode active material layer 17. By isolating the positive electrode active material layer 16 and the negative electrode active material layer 17, the separators 14 prevent short circuits due to contact between adjacent electrodes while allowing charge carriers such as lithium ions to pass through.

[0022] 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 or conductive resin material.

[0023] 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 (e.g., metal foil), film, or mesh. Examples of metal foils include aluminum foil, copper foil, nickel foil, titanium foil, and stainless steel foil. Examples of stainless steel foils include SUS 304, SUS 316, and SUS 301 as specified in JIS G 4305:2015. Using stainless steel foil as the current collector 15 ensures the mechanical strength of the current collector 15. The current collector 15 may also be an alloy foil or clad foil of the above metals. 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 100 μm.

[0024] 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 )

[0025] 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.

[0026] 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, as necessary, a conductive additive to enhance electrical conductivity, a binder, an electrolyte (polymer matrix, ion-conductive polymer, electrolyte solution, etc.), an electrolyte supporting salt (lithium salt) to enhance ionic conductivity, etc. The conductive additive is added to enhance the conductivity of each electrode (bipolar electrode 11, positive terminal electrode 12, negative terminal electrode 13). Examples of the conductive additive include acetylene black, carbon black, and graphite.

[0027] 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 (SBR); carboxymethyl cellulose; alginates such as sodium alginate and ammonium alginate; water-soluble cellulose ester crosslinked bodies; and starch-acrylic acid graft polymers. These binders may be used alone or in combination. Examples of solvents that may be used include water and N-methyl-2-pyrrolidone (NMP).

[0028] 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 multilayer structure. The multilayer structure may include, for example, a ceramic layer as an adhesive layer or a heat-resistant layer. The separator 14 may be impregnated with an electrolyte. The separator 14 may be composed of an electrolyte such as a polymer electrolyte or an inorganic electrolyte. Examples of the electrolyte impregnated in the separator 14 include a liquid electrolyte (electrolytic solution) containing a nonaqueous solvent and an electrolyte salt dissolved in the nonaqueous solvent, and a polymer gel electrolyte containing an electrolyte retained in a polymer matrix.

[0029] When the separator 14 is impregnated with an electrolyte solution, the electrolyte salt 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.

[0030] The first resin portion 20 is formed in a frame shape on the peripheral portion of the electrode stack 10 so as to surround the electrode stack 10. The first resin portion 20 can be joined to each of the one surface 15a and the other surface 15b of the current collector 15 at the peripheral portion 15c of each current collector 15. The first resin portion 20 forms an internal space S between the current collectors 15 adjacent to each other in the first direction D1 and serves to seal each of the internal spaces S. An electrolyte (not shown) is accommodated in each internal space S. That is, the first resin portion 20, together with the current collectors 15 adjacent to each other in the first direction D1, defines an internal space S that accommodates the electrolyte. The first resin portion 20 prevents the electrolyte from permeating to the outside.

[0031] The first resin portion 20 prevents moisture and the like from entering the internal space S from the outside of the electrode stack 10. For example, the first resin portion 20 may have a diffusion coefficient or a permeability coefficient adjusted to prevent air from passing through the resin, in order to prevent air from entering the internal space S from the outside of the electrode stack 10. The edge of the separator 14 is bonded to the first resin portion 20. The first resin portion 20 includes an insulating material. Examples of materials for the first resin portion 20 include various resin materials such as polypropylene, polyethylene, polystyrene, ABS resin, acid-modified polypropylene, acid-modified polyethylene, and acrylonitrile-styrene resin.

[0032] The first resin portion 20 includes a plurality of sealants 21, a plurality of spacers 22, and welded end portions 23. The sealants 21 are provided on each of the current collectors 15. Accordingly, the sealants 21 are stacked one on top of the other along the first direction D1. The sealants 21 are frame-shaped when viewed from the first direction D1 and are provided on the peripheral edge portion 15c of the current collector 15. The sealants 21 are provided so as to extend from one surface 15a of the current collector 15 through the end face to the other surface 15b, covering the peripheral edge portion 15c. The sealants 21 are welded to both the one surface 15a and the other surface 15b of the current collector 15. More specifically, each sealant 21 is frame-shaped when viewed from the first direction and is composed of a pair of base materials arranged to sandwich the peripheral edge portion 15c of the current collector 15. One of the pair of substrates is disposed at peripheral edge 15c of current collector 15 so as to extend from one surface 15a of current collector 15 beyond the end face and is welded to one surface 15a. The other of the pair of substrates is disposed at peripheral edge 15c of current collector 15 so as to extend from other surface 15b of current collector 15 beyond the end face and is welded to other surface 15b. The pair of substrates are overlapped with each other in a portion beyond the end face of current collector 15 and are partially welded to form welded end portions 23 as described below.

[0033] The spacer 22 is disposed so as to be interposed between adjacent seal materials 21 in the first direction D1. As a result, the spacer 22 maintains the space between adjacent seal materials 21, i.e., between adjacent current collectors 15. The spacer 22 has a frame shape when viewed from the first direction D1, and is disposed on the peripheral edge portion 15c of the current collector 15. The spacer 22 is in contact with a pair of seal materials 21 adjacent to each other in the first direction D1.

[0034] The welded end 23 is formed by welding together and integrating the ends (peripheral edges) of the multiple sealants 21 and the multiple spacers 22 on the side opposite the internal space S. In other words, the sealants 21 and the spacers 22 are not welded to each other except at the welded end 23, but are only in contact with each other. When viewed from the first direction D1, the welded end 23 has a frame shape that surrounds the electrode stack 10. The side of the welded end 23 on the side opposite the internal space S extends along the first direction D1 and forms the outer surface 20s of the first resin portion 20. In other words, the first resin portion 20 includes the outer surface 20s on the side opposite the internal space S.

[0035] The first resin part 20 has communication holes 27 formed therein that communicate with each of the multiple internal spaces S (see FIGS. 1 and 4 ). As an example, the communication holes 27 are formed so as to penetrate the spacer 22 and the welded end part 23. The communication holes 27 have one opening in the internal space S and the other opening 27h on the outer surface 20s of the first resin part 20. In the energy storage module 1, a cell C including one internal space S is formed between a pair of adjacent current collectors 15. Here, one communication hole 27 is formed for one cell C.

[0036] Therefore, the outer surface 20s of the first resin part 20 includes a first outer surface 20sA in which the opening 27h of the communication hole 27 is formed, and three other second outer surfaces 20sB, 20sC, and 20sD. The second outer surface 20sB is the surface opposite the first outer surface 20sA, and the second outer surface 20sC and the second outer surface 20sD are surfaces connecting the first outer surface 20sA and the second outer surface 20sB. Furthermore, both ends of the first resin part 20 in the first direction D1 are each formed of a sealing material 21. Therefore, the first end surface 20a and the second end surface 20b in the first direction D1 of the first resin part 20 are outer surfaces of a pair of sealing materials 21 arranged at both ends of the first resin part 20 in the first direction D1.

[0037] As described above, the outer surface of the first resin part 20 includes a first end face 20a in the first direction D1, a second end face 20b opposite the first end face 20a in the first direction D1, and four outer side faces 20s extending along the first direction D1 to connect the first end face 20a and the second end face 20b. The four outer side faces 20s are outer surfaces of the welded end part 23. A first outer side face 20sA, which is one of the four outer side faces 20s, has openings 27h of a plurality of communication holes 27 formed therein. Three second outer side faces 20sB, 20sC, and 20sD, which are different from the first outer side face 20sA, do not have openings 27h of the communication holes 27.

[0038] Here, FIGS. 5 and 6 are schematic diagrams showing a portion of the energy storage module shown in FIG. 1. FIG. 5A is an enlarged plan view of region R1 in FIG. 1, and FIG. 5B is an enlarged cross-sectional view taken along line Vb-Vb in FIG. 1. FIG. 6A is an enlarged plan view of region R2 in FIG. 1, and FIG. 6B is an enlarged cross-sectional view taken along line VIb-VIb in FIG. 1. The sealing body 50 shown in FIGS. 2, 3, 5, and 6 has a rectangular frame shape when viewed from the first direction D1 and is provided on the first end face 20a, the second end face 20b, and the outer surface 20s of the first resin portion 20. The sealing body 50 is bonded (welded) to each of the first end face 20a and the second end face 20b and the outer surface 20s. The sealing body 50 includes a laminate sheet 30 and a second resin portion (injected resin portion) 40. However, the sealing body 50 does not have to be frame-shaped.

[0039] The laminate sheet 30 has a rectangular frame shape when viewed from the first direction D1 and is provided on second outer surfaces 20sB, 20sC, and 20sD of the outer surface 20s of the first resin portion 20, as well as on the first end surface 20a and the second end surface 20b. The laminate sheet 30 includes a metal layer 30a, a first insulating layer 30b laminated on the metal layer 30a, and a second insulating layer 30c laminated on the metal layer 30a on the side opposite to the first insulating layer 30b. The laminate sheet 30 is welded to the first resin portion 20 at the first insulating layer 30b.

[0040] The first insulating layer 30b is made of an insulating resin. Examples of materials for the first insulating layer 30b include polypropylene, polyethylene, and polyamide. The material for the first insulating layer 30b can be selected from the same materials as the first resin portion 20 in terms of adhesion to the first resin portion 20. The metal layer 30a is made of a material with low moisture permeability (low moisture permeability coefficient), such as aluminum foil or stainless steel foil. The second insulating layer 30c is made of an insulating resin. Examples of materials for the second insulating layer 30c include polypropylene and nylon. As an example, the laminate sheet 30 is an aluminum laminate sheet, with polypropylene for the first insulating layer 30b, aluminum for the metal layer 30a, and polyethylene terephthalate for the second insulating layer 30c.

[0041] The laminate sheet 30 is welded to at least the first end face 20a and the second end face 20b, and here, is also welded to the second outer surfaces 20sB, 20sC, and 20sD. The laminate sheet 30 includes a pair of end face portions 31 arranged on the first end face 20a and the second end face 20b, respectively, and side face portions 32 arranged on the second outer surfaces 20sB, 20sC, and 20sD.

[0042] In this way, the laminate sheet 30 covers at least a portion of the first end face 20a and the second end face 20b of the first resin part 20 in the first direction D1 and almost the entire second outer surface 20sB, 20sC, 20sD, thereby contributing to suppressing moisture permeation and gas permeation (and improving pressure resistance) between the internal space S and the outside of the storage module 1, i.e., improving sealing performance, in the first direction D1 and the second direction D2 and third direction D3 that intersect the first direction D1.

[0043] The second resin portion 40 has a rectangular frame shape when viewed from a third direction D3 intersecting the first direction D1, and is provided on the first outer surface 20sA, the first end surface 20a, and the second end surface 20b of the outer surfaces 20s of the first resin portion 20. The second resin portion 40 is welded to at least the first end surface 20a and the second end surface 20b, and here, is also welded to the first outer surface 20sA. More specifically, the second resin portion 40 may be provided on the first end surface 20a, the second end surface 20b, and the first outer surface 20sA by injection molding.

[0044] The second resin part 40 includes a reinforcing part 41 and a frame part 42. As described below, a rectangular frame part 42 is formed on the first outer surface 20sA, on which the opening 27h of the communication hole 27 is formed, so as to surround the opening 27h when viewed from the third direction D3. The frame part 42 is provided so as to protrude in the third direction D3 from a base part 40p on the first outer surface 20sA of the second resin part 40. The base part 40p is a plate-shaped part welded to the first outer surface 20sA. As a result, the welded end part 23 and the base part 40p are stacked on the first outer surface 20sA along the third direction D3.

[0045] The reinforcing portion 41 is provided on each of the first end face 20 a and the second end face 20 b. More specifically, the reinforcing portion 41 is provided from the sealant 21 to the welded end portion 23. By providing the reinforcing portion 41 on the first end face 20 a and the second end face 20 b, the thickness of the resin portion in the first direction D1 is increased, i.e., the distance from the internal space S to the outside of the energy storage module 1 in the first direction D1, which contributes to suppressing moisture permeation and gas permeation (and improving pressure resistance) along the first direction D1 between the internal space S and the outside, i.e., improving sealing performance.

[0046] In addition, in a third direction D3 intersecting the first direction D1, a base portion 40p, which is a resin portion corresponding to the reinforcing portion 41, is provided on the first outer surface 20sA of the first resin portion 20. The thickness of the resin portion (sealing material 21 or spacer 22 and welded end portion 23) excluding the second resin portion 40 in the third direction D3, i.e., the distance from the internal space S to the outside of the energy storage module 1 in the third direction D3 excluding the second resin portion 40, is greater than in the first direction D1, so moisture permeation and gas permeation are less likely to occur than in the first direction D1. Furthermore, by providing the base portion 40p and providing a sealing film 45 (described later) on the frame portion 42, moisture permeation and gas permeation in the third direction D3 are further suppressed.

[0047] As described above, the frame portion 42 is provided on the first outer surface 20sA (via the base portion 40p) so as to have a rectangular frame shape surrounding the openings 27h of each of the plurality of communication holes 27, as viewed from the third direction D3 intersecting with the first outer surface 20sA. The base portion 40p has through holes at positions corresponding to the communication holes 27, thereby connecting the openings 27h of the communication holes 27 to the region 43 surrounded by the frame portion 42. The frame portion 42 is used, for example, when injecting electrolyte into each of the internal spaces S.

[0048] More specifically, when injecting the electrolyte solution, a nozzle of an electrolyte solution injection device is brought into close contact with the top surface of the frame portion 42, and the electrolyte solution is introduced into each region 43 from the nozzle. This allows the electrolyte solution to be injected into the internal space S through the communication holes 27 that connect to each region 43 via the openings 27h. A sealing film 45 is attached to the frame portion 42. The sealing film 45 may have the same layer structure and material as the laminate sheet 30, for example. This seals the communication holes 27 and the internal space S. In this way, the second resin portion 40 can have the function of injecting the electrolyte solution and sealing the internal space S, in addition to functioning as the sealer 50. That is, the second resin portion 40 also functions as an injection frame.

[0049] Next, the positional relationship between the various parts of the energy storage module 1 will be described. First, as shown in FIG. 1 , the first resin part 20 has a rectangular ring shape when viewed from the first direction D1, and is composed of parts corresponding to the four sides of the rectangle. One of the parts corresponding to the four sides is a first part 20A including a region in which the opening 27h of the communication hole 27 of the first outer surface 20sA is formed. The parts corresponding to the other three sides of the parts corresponding to the four sides are a second part 20B including the second outer surface 20sB, a second part 20C including the second outer surface 20sC, and a second part 20D including the second outer surface 20sD.

[0050] Here, of the four outer surfaces 20s of the first resin part 20, the one on which the opening 27h of the communication hole 27 is formed is referred to as the "first outer surface," and the others are referred to as the "second outer surface." Also, among the parts of the first resin part 20, the part including the periphery of the opening 27h of the communication hole 27 on the "first outer surface" when viewed from the first direction D1 is referred to as the "first portion," and the others are referred to as the "second portion."

[0051] Similarly, the spacer 22 has a rectangular ring shape when viewed from the first direction D1, and is composed of four first side portions 22A to 22D corresponding to the four sides of the rectangle. When viewed from the first direction D1, the first side portion 22A is a portion included in the first portion 20A of the first resin portion 20, the first side portion 22B is a portion included in the second portion 20B of the first resin portion 20, the first side portion 22C is a portion included in the second portion 20C of the first resin portion 20, and the first side portion 22D is a portion included in the second portion 20D of the first resin portion 20.

[0052] 5 illustrates a portion of the first resin portion 20 in the energy storage module 1, including the second portion 20D. The positional relationship between the current collector 15, the sealant 21, the spacer 22 (i.e., the first side portion 22D), and the laminate sheet 30 will be described with reference to FIG. 5 . As shown in FIG. 5 , when viewed from the first direction D1, the inner edge 21e of the sealant 21 is located inside (i.e., toward the internal space S) relative to the outer edge 15e of the current collector 15. Furthermore, when viewed from the first direction D1, the inner edge 30e of (the end surface portion 31) of the laminate sheet 30 is located inside the outer edge 15e of the current collector 15 and substantially coincides with the inner edge 21e of the sealant 21.

[0053] Furthermore, as viewed from the first direction D1, the inner edge 22e of the spacer 22 (first side portion 22D) is located inside the inner edge 21e of the sealing material 21. As a result, the spacer 22 includes a protruding portion 22p that protrudes inward from the inner edge 21e of the sealing material 21 as viewed from the first direction D1. In other words, as viewed from the first direction D1, the entire area where the sealing material 21 is provided becomes an area where the sealing material 21 and the spacer 22 overlap (a gripping area).

[0054] Therefore, when welding the laminate sheet 30 to the sealing material 21, the entire sealing material 21 (the entire first end surface 20a and the entire second end surface 20b) can be pressed in the first direction D1 by the sealer SD, ensuring a welding margin for the laminate sheet 30. The end of the separator 14 is overlapped with the protruding portion 20p and welded to the spacer 22.

[0055] Although not shown in FIG. 5, the portions of the energy storage module 1 corresponding to the second portions 20B and 20C of the first resin portion 20 have the same positional relationship.

[0056] 6 illustrates a portion of the power storage module 1, including the first portion 20A of the first resin portion 20. The same description will be given of the positional relationships among the current collector 15, the sealing material 21, the spacer 22 (i.e., the first side portion 22A), and the second resin portion 40 with reference to FIG. 6. As shown in FIG. 6, the inner edge 21e of the sealing material 21 is located inside the outer edge 15e of the current collector 15 (i.e., toward the internal space S) as viewed from the first direction D1. Furthermore, the inner edge 40e of the second resin portion 40 (reinforcement portion 41) is located inside the outer edge 15e of the current collector 15 and outside the inner edge 21e of the sealing material 21 as viewed from the first direction D1.

[0057] Furthermore, as viewed from the first direction D1, the inner edge 22e of the spacer 22 (first side portion 22A) is located inside the inner edge 21e of the sealing material 21. As a result, the spacer 22 includes a protruding portion 22p that protrudes inward from the inner edge 21e of the sealing material 21 as viewed from the first direction D1. The end of the separator 14 is overlapped with the protruding portion 22p and welded to the spacer 22. In other words, as viewed from the first direction D1, the entire area where the sealing material 21 is provided is the area where the sealing material 21 and the spacer 22 overlap.

[0058] Therefore, when the second resin part 40 is formed on the first resin part 20 by injection molding, the edge of the mold MD can be positioned directly above (directly below) the inner edge 21 e of the sealing material 21 and gripped along the first direction D1, thereby ensuring a region for forming the second resin part 40 (reinforcing part 41). Note that, here too, the end of the separator 14 is overlapped with the protruding part 20 p and welded to the spacer 22.

[0059] When forming the second resin portion 40 by injection molding, a mold MD is first attached to a laminate including the electrode stack 10 and the first resin portion 20. Then, the second resin portion 40 is molded by injecting resin into the molding space of the mold MD attached to the laminate. As an example, when attaching the mold MD, the mold MD can clamp (hold) an area (a gripping area) where the multiple current collectors 15, the multiple seal materials 21, and the multiple spacers 22 overlap as viewed from the first direction D1. In this case, no space is formed in the gripping area in the stacking direction where the spacers 22 are not present. This allows for stable clamping by the mold MD (the second resin portion 40 can be stably formed). In addition, when providing the end face portion 31 of the laminate sheet 30 on the first end face 20a and the second end face 20b on which the second resin portion 40 (reinforcement portion 41) is formed, the end face portion 31 may be provided before forming the second resin portion 40 by injection molding, or the end face portion 31 may be provided after forming the second resin portion 40 by injection molding.

[0060] As described above, in the energy storage module 1, the inner edges 22e of all of the first side portions 22A to 22D of the spacer 22 are located more inward than the inner edge 21e of the sealing material 21, and include the protruding portions 22p. Furthermore, in the energy storage module 1, the second resin portion 40 is provided only on the first portion 20A of the first resin portion 20 and the first portion 20A of the second portions 20B to 20D. Furthermore, in the energy storage module 1, the laminate sheet 30 is provided on the first portion 20A of the first resin portion 20 and the second portions 20B to 20D of the second portions 20B to 20D. Note that, in this embodiment, the end surface portions 31 of the laminate sheet 30 are also provided on the first end surface 20a and the second end surface 20b of the first portion 20A. In the first portion 20A, the end surface portion 31 may be disposed and joined to at least a portion of the first end surface 20a and the second end surface 20b that is exposed from the reinforcing portion 41 of the second resin portion 40. In other words, the end surface portion 31 may be provided on the first end surface 20a and / or the second end surface 20b prior to injection molding of the second resin portion 40, so that at least a portion of the end surface portion 31 is further disposed between the first end surface 20a and / or the second end surface 20b and the reinforcing portion 41.

[0061] Conductive members 60 functioning as terminals for extracting current from the energy storage module 1 are disposed and electrically connected to the one surface 15 a of the current collector 15 of the positive terminal electrode 12 and the other surface 15 b of the current collector 15 of the negative terminal electrode 13, which are exposed from the first resin portion 20. The conductive members 60 can be used to electrically connect a plurality of energy storage modules 1. The conductive members 60 can also be used as restraining members for applying a restraining load to the electrode stack 10. Furthermore, a cooling flow path may be formed in the conductive member 60. The electrode stack 10 can be cooled by circulating a cooling medium through the cooling flow path formed in the conductive member 60.

[0062] In some cases, a spacer is interposed between adjacent seal portions attached to the current collectors and facing each other in the stacking direction to form an internal space between the adjacent current collectors. In this case, from the viewpoint of ensuring the capacity of the internal space, it is possible to adopt a configuration in which the inner edge of the spacer is positioned outside the inner edge of the seal portion (i.e., the spacer portion is recessed).

[0063] On the other hand, a sealing body may be provided outside the sealed portion for various purposes, such as suppressing moisture permeation between the internal space and the outside, suppressing gas permeation, improving pressure resistance, etc. In this case, it is conceivable to improve the sealing property by placing a sheet-like sealing body on the sealed portion, applying heat to the sealing body with a sealer and applying pressure in the stacking direction to weld it to the sealed portion, or by arranging a mold so as to grip the sealed portion along the stacking direction and forming the sealing body by injection molding using the mold.

[0064] In either case, it may be difficult to apply the pressing force or gripping force to the area where the seal is provided where no spacer is interposed between the seals (the area inside the inner edge of the spacer), making it difficult to provide the seal. In such a situation, it is desirable to make the area where the seal is provided as large as possible relative to the entire area where the seal is provided, so that the seal can be provided larger and more stably.

[0065] In the energy storage module 1 according to this embodiment, a first resin portion 20 is provided on an electrode stack 10 including electrodes (bipolar electrodes 11, positive terminal electrodes 12, and negative terminal electrodes 13) stacked along a first direction D1. A sealing body 50 is bonded to a first end surface 20a and a second end surface 20b of the first resin portion 20 in the first direction D1. In the first resin portion 20, spacers 22 are interposed between sealants 21 provided on peripheral portions 15c of the current collectors 15 of the electrodes. As a result, an internal space S is formed between the sealants 21 and the spacers 22 between adjacent current collectors 15 along the first direction D1. Furthermore, the first resin portion 20 has a plurality of communication holes 27 formed therein, which communicate between a first outer surface 20sA of the four outer surfaces 20s of the first resin portion 20 and the internal space S. The communication holes 27 can be used, for example, as injection ports for injecting an electrolyte into the internal space S.

[0066] In the first portion 20A of the first resin portion 20, including the region of the first outer surface 20sA where the opening 27h of the communication hole 27 is formed, at least a portion (here, the entire portion) of the inner edge 22e of the spacer 22 is positioned inside the inner edge 21e of the sealing material 21 when viewed from the first direction D1. Therefore, in at least this portion, the spacer 22 extends beyond the inner edge 21e of the sealing material 21 when viewed from the first direction D1. This allows the injection molding mold MD, heat sealer, or the like to be positioned in this portion as a gripping region, and the sealing body 50 to be formed by applying a pressing force and gripping force. This allows the sealing body 50 to be stably provided for improved sealing performance.

[0067] Furthermore, in the energy storage module 1, the sealing body 50 includes the second resin part 40 welded to the first end face 20 a and the second end face 20 b in the first portion 20 A. Therefore, by using the portion where the inner edge 22 e of the spacer 22 is positioned more inward than the inner edge 21 e of the sealing material 21 as a gripping region and arranging the mold MD for injection molding as described above, it is possible to stably provide the second resin part 40, which is an injected resin part.

[0068] Furthermore, in the energy storage module 1, the sealing body 50 has a laminate sheet 30 including a metal layer 30a and a first insulating layer 30b laminated on the metal layer 30a, and the laminate sheet 30 is welded at the first insulating layer 30b to the first end surface 20a and the second end surface 20b of the first resin part 20. Therefore, the laminate sheet 30 suitably suppresses moisture permeation and gas permeation in the internal space S and improves strength.

[0069] Furthermore, in the energy storage module 1, the electrode stack 10 includes separators 14 interposed between each of the plurality of electrodes adjacent to each other in the first direction D1, and the spacers 22 include protruding portions 22p that protrude inward from the inner edge 21e of the sealing material 21 as viewed in the first direction D1. The ends of the separators 14 are overlapped with and welded to the protruding portions 22p. Therefore, if the melting point of the spacers 22 is relatively high, short circuits between the current collectors 15 will not occur unless the melting point of the spacers 22 is exceeded, and heat resistance will be improved.

[0070] In the energy storage module according to the present disclosure, the four outer surfaces may include three second outer surfaces that are different from the first outer surface, and in the second portion including each of the three second outer surfaces of the first resin part, the inner edge of the spacer may be located more inward than the inner edge of the sealing material when viewed from the first direction. In this case, in the second portion including the second outer surfaces other than the first outer surface on which the opening of the communication hole of the first resin part is formed, the inner edge of the spacer is located more inward than the inner edge of the sealing material, making it possible to provide the sealing body by applying a pressing force or a gripping force.

[0071] In the energy storage module according to the present disclosure, the sealing body may include an injected resin portion welded to the first end surface and the second end surface in the first portion. In this case, the first portion, including a portion where the inner edge of the spacer is positioned more inward than the inner edge of the sealing material, becomes the gripping region. By placing a mold for injection molding in this gripping region as described above, it is possible to stably provide the sealing body including the injected resin portion.

[0072] In the energy storage module according to the present disclosure, the sealing body may include a laminate sheet including a metal layer and an insulating layer laminated on the metal layer, and the laminate sheet may be welded to the first end face and the second end face. In this case, the laminate sheet including the metal layer advantageously suppresses moisture permeation and gas permeation in the internal space and improves strength.

[0073] In the energy storage module according to the present disclosure, the electrode stack may include a separator interposed between each of the plurality of electrodes adjacent to each other in the first direction, and an end of the separator may be disposed between the sealing material and the spacer in the first direction. In this case, if the melting point of the spacer is relatively high, a short circuit between the current collectors will not occur unless the melting point of the spacer is exceeded, and heat resistance will be improved.

[0074] The above embodiment describes one aspect of the power storage module according to the present disclosure. Therefore, the power storage module according to the present disclosure may be any modified version of the above-described power storage module 1.

[0075] For example, the spacer 22 may have a multilayer structure as shown in (a) of Fig. 7. As an example, the spacer 22 may include an intermediate layer 221, a pair of outermost layers 222 laminated on both sides of the intermediate layer 221, and a pair of adhesive layers 223 interposed between the intermediate layer 221 and the outermost layer 222. The intermediate layer 221 may be made of a material (e.g., PP) that has excellent heat resistance and gas permeability, and the outermost layer 222 may be made of a material (e.g., a mixed material of PE and PP) that has excellent compatibility with the material of the sealing material 21 (e.g., low-density PE). The adhesive layer 223 is a layer that bonds the intermediate layer 221 and the outermost layer 222 and is provided as needed (i.e., it may be omitted).

[0076] Similarly, as shown in (b) of FIG. 7, the sealing material 21 may have a multilayer structure. In the example of (b) of FIG. 7, each of a pair of base materials 21a constituting one sealing material 21 has a multilayer structure. In this example, each of the base materials 21a includes an intermediate layer 211, a pair of outermost layers 212 laminated on both sides of the intermediate layer 211, and a pair of adhesive layers 213 interposed between the intermediate layer 211 and the outermost layer 212, respectively. The intermediate layer 211, the outermost layer 212, and the adhesive layer 213 may be made of the same materials as the intermediate layer 221, the outermost layer 222, and the adhesive layer 223 shown in (a) of FIG. 7. Note that hatching of various parts is omitted in FIG. 7.

[0077] Furthermore, in the energy storage module 1, because the end of the metal layer 30a may be exposed at the end (inner edge 30e) of the laminate sheet 30, an insulator (not shown) may be provided to cover the end of the laminate sheet 30. In this case, an example of the insulator may be an insulating film attached from one surface 15a and / or the other surface 15b of the current collector 15 to the end of the laminate sheet 30. In this case, the laminate sheet 30 is insulated. As a result, a short circuit between the positive terminal electrode 12 and the negative terminal electrode 13 of the electrode stack 10 via the metal layer 30a of the laminate sheet 30 is suppressed.

[0078] Furthermore, in the above embodiment, an example has been described in which the entire inner edge 22 e of the spacer 22 is positioned more inward than the inner edge 21 e of the sealing material 21 when viewed from the first direction D1. However, in the energy storage module 1, it is sufficient that at least a part of the inner edge 22 e of the spacer 22 (for example, at least one side portion) is positioned more inward than the inner edge 21 e of the sealing material 21.

[0079] 8 , in the energy storage module 1, in the second portion 20B including the second outer side surface 20sB of the first resin portion 20, the inner edge 22e of the spacer 22 may be located outward from the inner edge 21e of the sealing material 21 as viewed in the first direction D1. That is, in the energy storage module 1, in the first portion 20A including at least a region where the opening 27h of the communication hole 27 of the first outer side surface 20sA of the first resin portion 20 is formed, at least a part of the inner edge 22e of the spacer 22 may be located inward from the inner edge 21e of the sealing material 21 as viewed in the first direction D1.

[0080] Therefore, for second portions 20C, 20D including the other second outer side surfaces 20sC, 20sD of the first resin portion 20, the inner edge 22e of the spacer 22 may be similarly positioned outside the inner edge 21e of the sealing material 21. In this case, in second portions 20B, 20C, 20D including the second outer side surfaces 20sB, 20sC, 20sD other than the first outer side surface 20sA on which the opening 27h of the communication hole 27 of the first resin portion 20 is formed, the inner edge 22e of the spacer 22 is positioned outside the inner edge 21e of the sealing material 21, thereby making it possible to ensure a large volume of the internal space S.

[0081] 8 , in the energy storage module 1, when viewed from the first direction D1, the inner edges 22e of the second side portions (first side portions 22B to 22D) other than the first side portion 22A among the multiple side portions of the spacer 22 may be positioned outside the inner edge 21e of the sealing material 21. In this case, it is possible to stably provide the sealing body 50 on the first side portion 22A, while ensuring a large volume of the internal space S in the first side portions 22B to 22D. Note that, among the multiple side portions of the spacer 22, the side portions whose inner edges are positioned inside the inner edge 21e of the sealing material 21 are referred to as "first side portions," and the remaining side portions are referred to as "second side portions."

[0082] In this case, before stacking the electrodes to form the electrode stack 10, the end surface portion 31 of the laminate sheet 30 can be pressed and welded with a sealer SD to the first resin portion 20 provided on the peripheral edge portion 15c of the current collector 15. In this case, the end surface portion 31 is provided before forming the second resin portion 40 by injection molding, but the end surface portion 31 may also be provided after forming the second resin portion 40 by injection molding.

[0083] 8 , in the energy storage module 1, the separator 14 may extend to reach between the sealing material 21 and the spacer 22. In this case, the peripheral edge of the separator 14 is sandwiched between the sealing material 21 and the spacer 22 and welded to the first resin part 20.

[0084] Furthermore, the portion of the first resin part 20 corresponding to the first outer side surface 20sA may include a first portion including a region on the first outer side surface 20sA where the opening 27h of the communication hole 27 is formed, and a second portion other than the first portion, and in the second portion, the inner edge 22e of the spacer 22 may be positioned outside the inner edge 21e of the sealing material 21. In this case, the inner edge 22e of the spacer 22 is positioned inside the inner edge 21e of the sealing material 21 only within the minimum necessary range, making it possible to ensure a large internal space S.

[0085] Fig. 9 is a schematic cross-sectional view of an energy storage module according to another modified example. In the example of Fig. 9, similar to the example shown in Fig. 8, the separator 14 extends to reach between the sealant 21 and the spacer 22. As a result, the end of the separator 14 is disposed between the sealant 21 and the spacer 22 in the first direction D1. Also in this example, the peripheral edge of the separator 14 is sandwiched between the sealant 21 and the spacer 22 and welded to the first resin part 20.

[0086] 9 , in the energy storage module 1, the portion of the first resin part 20 corresponding to the first outer side surface 20sA includes a first part 20A including a region in the first outer side surface 20sA where the opening 27h of the communication hole 27 is formed, and other second parts 20B to 20D, and in all of the second parts 20B to 20D (all sides of the first resin part 20), the inner edge 22e of the spacer 22 may be located more inward than the inner edge 21e of the sealing material 21. In this case, it is possible to provide the sealing body 50 by applying a pressing force or a gripping force.

[0087] In the above embodiment, the sealing body 50 has a rectangular annular shape when viewed from the first direction D1, but the sealing body 50 does not have to be annular when viewed from the first direction D1. In this case, the sealing body 50 only needs to be provided in at least one of the portions (first portion 20A and second portions 20B to 20D) corresponding to the four sides of the first resin portion 20. Furthermore, the sealing body 50 may be provided in only a portion of the portion corresponding to one side of the first resin portion 20.

[0088] In the above embodiment, the laminate sheet 30 includes the metal layer 30 a. However, the laminate sheet 30 may include a resin layer instead of the metal layer 30 a. The resin layer may be made of polypropylene, polyethylene, polyamide, polyimide, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, or the like.

[0089] REFERENCE SIGNS LIST 1...energy storage module, 10...electrode laminate, 15...current collector, 15e...outer edge, 20...first resin part, 20A...first part, 20B, 20C, 20D...second part, 20a...first end face, 20b...second end face, 20s...outer surface, 20sA...first outer surface, 20sB, 20sC, 20sD...second outer surface, 21...sealing material, 21e, 22e, 30e, 40e...inner edge, 22...spacer, 22p...protruding part, 22A...first side portion, 22B, 22C, 22D...first side portion, 27...communicating hole, 27h...opening, 30...laminate sheet, 30a...metal layer, 30b...first insulating layer (insulating layer), 40...second resin part (injected resin part), S...internal space.

Claims

1. an electrode stack including a current collector and a plurality of electrodes stacked along a first direction; a first resin portion that forms an internal space between the current collectors adjacent to each other in the first direction and is provided in the electrode stack so as to seal the internal space; a sealing body joined to the first resin portion; Equipped with The outer surface of the first resin portion is a first end surface in the first direction; a second end surface opposite the first end surface in the first direction; four outer side surfaces extending along the first direction so as to connect the first end surface and the second end surface; Including, the sealing body is bonded to at least the first end surface and the second end surface, The first resin portion is a plurality of frame-shaped seal members provided on the periphery of each of the plurality of current collectors; a plurality of frame-shaped spacers that are interposed between the sealing materials adjacent to each other in the first direction and form the internal space between the current collectors together with the sealing materials; a welding end portion formed by welding the outer peripheral edges of the plurality of sealing materials and the plurality of spacers on the opposite side to the internal space, the welding end portion including the four outer surfaces; a plurality of communication holes that are open to a first outer surface that is one of the four outer surfaces and to the internal space, thereby communicating the internal space with an outside of the first resin portion; Including, in a first portion including at least a region of the first outer surface of the first resin portion where an opening of the communication hole is formed, an inner edge of the sealant is located inside an outer edge of the current collector as viewed from the first direction, In at least the first portion, an inner edge of the sealing body coincides with an inner edge of the sealing material or is located outside the inner edge of the sealing material when viewed from the first direction; At least in the first portion, when viewed from the first direction, at least a part of an inner edge of the spacer is located inside an inner edge of the sealant, the sealing material is welded to both sides of the current collector, The spacer is in contact with a pair of the sealing materials adjacent to each other in the first direction. Energy storage module.

2. The four outer surfaces include three second outer surfaces that are different from the first outer surface, In a second portion including each of the three second outer surfaces of the first resin portion, an inner edge of the spacer is located more inward than an inner edge of the sealant as viewed from the first direction. The energy storage module according to claim 1 .

3. the sealing body includes an injected resin portion welded to the first end surface and the second end surface in the first portion, The energy storage module according to claim 1 .

4. the sealing body includes a laminate sheet including a metal layer and an insulating layer laminated on the metal layer, The laminate sheet is welded to the first end surface and the second end surface. The energy storage module according to claim 1 .

5. the electrode stack includes a separator interposed between each of the plurality of electrodes adjacent to each other in the first direction, an end portion of the separator is disposed between the sealant and the spacer in the first direction; The storage module according to any one of claims 1 to 4.