Power storage module manufacturing method

Abstract

To provide a power storage module manufacturing method capable of suppressing the generation of a defective article.SOLUTION: A power storage module manufacturing method comprises: a step S101 of preparing a battery body 1A; a step S103 of binding the battery body 1A by using a binding jig 50; and a step S105 of adhering and integrating a plurality of seal materials 21 of the battery body 1A. The plurality of seal materials is constructed by: an inner side part 21a that is overlapped with the peripheral edge part 15c of the electrode of the battery body 1A, and an outer side part 21b that is positioned to the side outer from the peripheral edge part 15c. The binding jig 50 contains: a pair of binding plates 51 and 52; and a resin member 55 having an elastic property that is higher than that of the binding plates 51 and 52. In the step S103, the resin member 55 is arranged so as to be interposed to between the one binding plate 51 and the seal material 21 at the outermost part. In the step S105, the end part of the outside part 21b of the plurality of seal materials 21 is heated by a heater 60 in a state where the battery body 1A is bonded by the binding jig 50 each other and is adhered.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a power storage module.

Background Art

[0002] Patent Document 1 describes a method for manufacturing a gel electrolyte bipolar battery. This manufacturing method includes a step of laminating a required number of bipolar electrodes each including a current collector provided with a negative electrode layer and a positive electrode layer, a step of performing sealing except for a part of a seal that also serves as insulation between current collectors, a step of injecting a solution containing an electrolytic solution into each cell, and a step of sealing the remaining seal portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the bipolar electrode described in Patent Document 1 above, a resin frame for sealing may be provided so as to overlap the peripheral portion of the current collector. At this time, when using a resin frame including an overhanging portion that protrudes outside the edge of the current collector, a gap corresponding to the thickness of the current collector is formed between the overhanging portions adjacent to each other in the stacking direction. Therefore, for example, when welding the overhanging portions to each other using a non-contact heater, a part of the gap corresponding to the thickness of the current collector remains as a large void inside the welded portion, and there is a risk of producing defective products with reduced sealing performance. In other words, when welding the overhanging portions to each other using a non-contact heater, it is desirable to suppress the occurrence of defective products by reducing the voids remaining inside the welded portion.

[0005] Therefore, an object of the present disclosure is to provide a method for manufacturing a power storage module capable of suppressing the occurrence of defective products.

Means for Solving the Problems

[0006] The method for manufacturing a power storage module according to the present disclosure is a method for manufacturing a power storage module in which a sealing body is provided so as to surround an electrode when viewed from a first direction. For each of a plurality of electrodes laminated along the first direction, a battery body provided with a sealing material composed of an inner portion overlapping the peripheral edge portion of the electrode and an outer portion located outside the peripheral edge portion is prepared in a first step. After the first step, a second step of restraining the battery body along the first direction using a restraining jig is performed. After the second step, a third step of forming a sealing body by welding and integrating the outer portions of the plurality of sealing materials with each other is performed. The restraining jig includes a pair of restraining plates and a resin member more elastic than the restraining plates. In the second step, the pair of restraining plates are arranged so as to sandwich the battery body along the first direction, and the resin member is arranged so as to be interposed between one of the pair of restraining plates and the outermost sealing material in the first direction and so as to overlap the outer portion along the first direction. In the third step, in a state where the battery body is restrained by the restraining jig, a heater is arranged so as to face the outer portion while being separated from the outer portion, and the ends of the outer portions of the plurality of sealing materials are heated by the heater and welded to each other to form a sealing body.

[0007] In this manufacturing method, first, a battery body is prepared. The battery body has a plurality of electrodes laminated along a first direction, and a plurality of sealing materials provided on each of the plurality of electrodes. Each of the plurality of sealing materials includes an inner portion overlapping the peripheral edge of the electrode and an outer portion located outside the peripheral edge of the electrode. Therefore, in the battery body, a gap corresponding to the thickness of the electrode (for example, the current collector among the electrodes) is formed between the outer portions of the sealing materials adjacent to each other in the stacking direction. In contrast, in this manufacturing method, in a subsequent step, the battery body is constrained using a constraint jig. At this time, a pair of constraint plates of the constraint jig are arranged so as to sandwich the battery body, and a resin member having higher elasticity than the constraint plates in the constraint jig is interposed between the constraint plate and the outermost sealing material. Thereby, a constraint force can be applied to the laminated portion of the sealing material in the stacking direction, and the gap between the adjacent sealing materials can be reduced. Then, in that state, the outer portions of the plurality of sealing materials are welded to each other using a non-contact heater. Thereby, the void remaining inside the welded portion between the sealing materials can be reduced, and the occurrence of defective products can be suppressed.

[0008] In the manufacturing method of the power storage module according to the present disclosure, the resin member includes an elastic member, and in the second step, the resin member may be arranged so that the elastic member overlaps the outer portion when viewed from the first direction, and the outer portion may be pressed by the elastic member.

[0009] In the manufacturing method of the power storage module according to the present disclosure, the resin member includes a flat first heat-resistant member, and the first heat-resistant member may be arranged between one constraint plate and the elastic member.

[0010] In the manufacturing method of the power storage module according to the present disclosure, the resin member includes a flat second heat-resistant member, and in the second step, the second heat-resistant member may be arranged so as to sandwich the battery body along the first direction together with the first heat-resistant member and the elastic member, and so as to overlap the sealing material along the first direction.

[0011] It may also be.

[0012] In the method for manufacturing a power storage module according to the present disclosure, in the third step, a plurality of elongated heaters may be arranged such that the longitudinal direction of the heater is along the first direction and the heaters are aligned along the end portions of the outer portion.

[0013] In the method for manufacturing a power storage module according to the present disclosure, the outer portion has a rectangular frame shape with four end portions when viewed from the first direction. In the third step, a plurality of heaters may be arranged along two end portions that share one corner portion of the outer portion, and the two end portions may be heated together.

Advantages of the Invention

[0014] According to the present disclosure, it is possible to provide a method for manufacturing a power storage module capable of suppressing the occurrence of defective products.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0016] Hereinafter, a power storage module according to an embodiment will be described with reference to the drawings. In the description of each figure, the same or corresponding elements may be denoted by the same reference numerals, and redundant descriptions may be omitted. Also, in each figure, an orthogonal coordinate system that defines an X direction, a Y direction orthogonal to the X direction, and a Z direction orthogonal to the X direction and the Y direction may be shown.

[0017] FIG. 1 is a schematic cross-section of a power storage module according to this embodiment. FIG. 2 is a schematic plan view of the power storage module shown in FIG. 1. The power storage module 1 shown in FIGS. 1 and 2 is a power storage module used for batteries of various vehicles such as forklifts, hybrid vehicles, and electric vehicles, for example. The power storage module 1 is a secondary battery such as a nickel-metal hydride secondary battery or a lithium-ion secondary battery, for example. The power storage module 1 may be an electric double layer capacitor or an all-solid-state battery. Here, the case where the power storage module 1 is a lithium-ion secondary battery is exemplified.

[0018] The power storage module 1 includes an electrode laminate 10 and a sealing body 20. The electrode laminate 10 includes a plurality of electrodes laminated along the Z direction (first direction). The plurality of electrodes include a plurality of bipolar electrodes 11, a negative terminal electrode 12, and a positive terminal electrode 13. A separator 14 is interposed between adjacent electrodes.

[0019] The bipolar electrode 11 has a current collector 15, a positive electrode active material layer 16 (second active material layer), and a negative electrode active material layer 17 (first active material layer). The current collector 15 has a rectangular sheet shape, for example. The current collector 15 includes one surface 15a and the other surface 15b. As an example, the other surface 15b is a first surface intersecting the Z direction, and the one surface 15a is a second surface intersecting the Z direction and opposite to the first surface. Here, one surface 15a of the current collector 15 is a surface facing one direction of the Z direction (the direction from the positive terminal electrode 13 to the negative terminal electrode 12 in FIG. 1), and the other surface 15b of the current collector 15 is a surface facing the other direction of the Z direction (the direction from the negative terminal electrode 12 to the positive terminal electrode 13 in FIG. 1).

[0020] The positive electrode active material layer 16 (second active material layer) is provided on one surface 15a (second surface) of the current collector 15. The negative electrode active material layer 17 (first active material layer) is provided on the other surface 15b (first surface) of the current collector 15. The plurality of bipolar electrodes 11 are laminated 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. Grooves may be formed in the positive electrode active material layer 16 and the negative electrode active material layer 17.

[0021] The positive electrode active material layer 16 and the negative electrode active material layer 17 are rectangular when viewed from the Z direction. The negative electrode active material layer 17 is slightly larger than the positive electrode active material layer 16 when viewed from the Z direction. That is, in a plan view when viewed from the Z direction, 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 Z direction, 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.

[0022] The negative terminal electrode 12 has the current collector 15 and the negative electrode active material layer 17 provided on the other surface 15b of the current collector 15. The negative terminal electrode 12 does not have the positive electrode active material layer 16 and the negative electrode active material layer 17 on one surface 15a of the current collector 15. That is, no active material layer is provided on one surface 15a of the current collector 15 of the negative terminal electrode 12. The negative terminal electrode 12 is laminated on the bipolar electrode 11 at one end of the electrode laminate 10 in the Z direction. The negative terminal electrode 12 is laminated on the bipolar electrode 11 such that its negative electrode active material layer 17 faces the positive electrode active material layer 16 of the bipolar electrode 11.

[0023] The positive terminal electrode 13 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 13 does not have the positive electrode active material layer 16 and the negative electrode active material layer 17 on the other surface 15b which is the opposite surface of one surface 15a of the current collector 15. That is, no active material layer is provided on the other surface 15b of the current collector 15 of the positive terminal electrode 13. The positive terminal electrode 13 is laminated on the bipolar electrode 11 at one end of the electrode laminate 10 in the Z direction. The positive terminal electrode 13 is laminated on the bipolar electrode 11 such that its positive electrode active material layer 16 faces the negative electrode active material layer 17 of the bipolar electrode 11.

[0024] 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 as the current collector, but the current collectors of the bipolar electrode 11, the negative terminal electrode 12, and the positive terminal electrode 13 may be the same as each other or different from each other. Also, the surface of the negative terminal electrode 12 where the negative electrode active material layer 17 is not provided and the surface of the positive terminal electrode 13 where the positive electrode active material layer 16 is not provided do not come into contact with the electrolytic solution because they come into contact with, for example, a tab or the like for taking out current.

[0025] The separator 14 is disposed between adjacent bipolar electrodes 11, between the negative terminal electrode 12 and the bipolar electrode 11, and between the positive terminal electrode 13 and the bipolar electrode 11. The separator 14 is interposed between the positive electrode active material layer 16 and the negative electrode active material layer 17. The separator 14 is a member that allows charge carriers such as lithium ions to pass through, and by isolating the positive electrode active material layer 16 and the negative electrode active material layer 17, it prevents a short circuit due to contact between adjacent electrodes.

[0026] The current collector 15 is a chemically inert electrical conductor for continuously passing an electric current through the positive electrode active material layer 16 and the negative electrode active material layer 17 during discharge or charging of the lithium-ion secondary battery. The material of the current collector 15 is, for example, a metal material, a conductive resin material, a conductive inorganic material, or the like. Examples of the conductive resin material include a conductive polymer material or a resin obtained by adding a conductive filler to a non-conductive polymer material as needed. The current collector 15 may include a plurality of layers. In this case, each layer of the current collector 15 may contain the above-mentioned metal material and / or conductive resin material.

[0027] 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 have a shape such as a plate shape, a foil shape (e.g., a metal foil), a film shape, or a mesh shape. Examples of the metal foil include aluminum foil, copper foil, nickel foil, titanium foil, or stainless steel foil. The current collector 15 may be an alloy foil of the above-mentioned metals or a foil obtained by integrating a plurality of metal foils. When the current collector 15 has a foil shape, the thickness of the current collector 15 may be, for example, 1 μm to 200 μm. In the present embodiment, the current collector 15 is a foil obtained by integrating an aluminum foil and a copper foil, or a foil obtained by vapor-depositing copper on an aluminum foil.

[0028] The positive electrode active material layer 16 contains a positive electrode active material capable of occluding 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, polyanion-based compounds, and the like. The positive electrode active material may be any material that can be used in a lithium-ion secondary battery. The positive electrode active material layer 16 may contain a plurality of positive electrode active materials. In the present embodiment, the positive electrode active material layer 16 contains olivine-type lithium iron phosphate (LiFePO 4 ) as a composite oxide.

[0029] The negative electrode active material layer 17 contains a negative electrode active material capable of occluding and releasing charge carriers such as lithium ions. The negative electrode active material may be any of a single 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 also be an element capable of alloying with lithium or its compound, etc. Examples of carbon include natural graphite, artificial graphite, hard carbon (carbon with low graphitization property), or soft carbon (carbon with high graphitization property), etc. Examples of artificial graphite include highly oriented graphite, mesocarbon microbeads, etc. Examples of elements capable of alloying with lithium include silicon or tin, etc. In the present embodiment, the negative electrode active material layer 17 contains graphite as a carbon-based material.

[0030] Each of the positive electrode active material layer 16 and the negative electrode active material layer 17 (hereinafter, may be simply referred to as the "active material layer") may further contain a conductive assistant, a binder, an electrolyte (polymer matrix, ion-conductive polymer, electrolyte solution, etc.), an electrolyte supporting salt (lithium salt, etc.) for enhancing ion conductivity, etc., as necessary. The conductive assistant is added to enhance the conductivity of each electrode (bipolar electrode 11, negative electrode terminal electrode 12, positive electrode terminal electrode 13). The conductive assistant is, for example, acetylene black, carbon black, or graphite, etc.

[0031] Examples of the binder include fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluororubber, thermoplastic resins such as polypropylene and polyethylene, imide-based resins such as polyimide and polyamideimide, alkoxysilyl group-containing resins, acrylic resins such as acrylic acid or methacrylic acid, styrene-butadiene rubber (SBR), carboxymethyl cellulose, alginates such as sodium alginate and ammonium alginate, water-soluble cellulose ester crosslinked products, starch-acrylic acid graft polymers, etc. These binders may be used alone or in combination. Examples of the solvent for the binder include water, N-methyl-2-pyrrolidone (NMP), etc.

[0032] Separator 14 may be, for example, a porous sheet or nonwoven fabric containing a polymer that absorbs and retains an electrolyte. Examples of the material of separator 14 include polypropylene, polyethylene, polyolefin, polyester, and the like. Separator 14 may have a single-layer structure or a multilayer structure. The multilayer structure may have, for example, an adhesive layer or a ceramic layer as a heat-resistant layer. Separator 14 may be impregnated with an electrolyte. The electrolyte impregnated in separator 14 is a liquid electrolyte (electrolyte solution) containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent.

[0033] Examples of the electrolyte salt of the electrolyte solution include LiClO 4 , LiAsF 6 , LiPF 6 , LiBF 4 , LiCF 3 SO 3 , LiN(FSO 2 ) 2 , LiN(CF 3 SO 2 ) 2 and other known lithium salts may be used. Further, as the non-aqueous solvent, known solvents such as cyclic carbonates, cyclic esters, chain carbonates, chain esters, and ethers may be used. Note that two or more of these known solvent materials may be used in combination.

[0034] Sealing body 20 is provided on the electrode laminate 10 so as to surround the electrode laminate 10 when viewed from the Z direction, and is formed in a rectangular tubular shape at the peripheral edge of the electrode laminate 10. Sealing body 20 can be joined (welded) to each of one surface 15a and the other surface 15b of current collector 15 at the peripheral edge 15c of each current collector 15. Sealing body 20 forms an internal space S between current collectors 15 adjacent in the Z direction, and is for sealing each of the internal spaces S. An electrolyte (for example, an electrolyte solution) is accommodated in each internal space S. Sealing body 20 can suppress the outflow of the electrolyte solution accommodated in internal space S to the outside. Further, sealing body 20 can suppress the intrusion of air, moisture, etc. from the outside of electrode laminate 10 into internal space S.

[0035] The edge of the separator 14 is joined to the sealing body 20. The sealing body 20 contains an insulating material. Examples of the material of the sealing body 20 include various resin materials such as polypropylene, polyethylene, polystyrene, ABS resin, acid-modified polypropylene, acid-modified polyethylene, acrylonitrile styrene resin, etc.

[0036] The sealing body 20 includes a plurality of resin sealing materials 21 and a plurality of resin spacers 22. The sealing materials 21 are provided at the peripheral edges of the plurality of electrodes. More specifically, the sealing materials 21 are provided on each of the current collectors 15. Therefore, the plurality of sealing materials 21 are laminated along the Z direction. The sealing material 21 has a frame shape (here, a rectangular frame shape) along the outer shape of the current collector 15 as viewed from the Z direction, and is provided at the peripheral edge 15c of the current collector 15. The sealing material 21 is 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 15c.

[0037] That is, the sealing material 21 includes, on each of the one surface 15a and the other surface 15b of the current collector 15, an inner portion 21a that overlaps the current collector 15 as viewed from the Z direction, and an outer portion 21b that is located outside the outer edge 15e of the current collector 15. The sealing material 21 does not overlap the current collector 15 in the outer portion 21b as viewed from the Z direction. The inner portion 21a and the outer portion 21b are each frame-shaped (here, rectangular frame-shaped) as viewed from the Z direction. A pair of adjacent portions of the sealing material 21 sandwiching the current collector 15 are connected to each other in the outer portion 21b. The inner portion 21a of the sealing material 21 is welded to the one surface 15a and the other surface 15b at the peripheral edge 15c of the current collector 15, respectively.

[0038] In the present embodiment, although the sealing materials provided on the current collectors 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 denoted by the same reference numeral as the sealing material 21, 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 each other or may be different from each other.

[0039] The spacer 22 is arranged so as to be interposed between the respective sealing materials 21 adjacent to each other in the Z direction. Thereby, the spacer 22, together with a pair of sealing materials 21 adjacent to each other in the Z direction, holds the interval between the current collectors 15 adjacent to each other in the Z direction. The internal space S is defined by a pair of current collectors 15 adjacent to each other in the Z direction, the spacer 22, and a pair of sealing materials 21 adjacent to the spacer 22. Thus, each of the plurality of spacers 22 forms the internal space S between the current collectors 15 adjacent to each other in the Z direction together with the sealing materials 21 adjacent to each other along the Z direction.

[0040] The spacer 22 has a frame shape (here, a rectangular frame shape) along the outer shape of the current collector 15 as viewed from the Z direction, and is arranged on the peripheral edge portion 15c of the current collector 15 as viewed from the Z direction. That is, the spacer 22 includes an inner portion 22a that overlaps the current collector 15 as viewed from the Z direction and an outer portion 22b that is located outside the outer edge 15e of the current collector 15. The spacer 22 does not overlap the current collector 15 in the outer portion 22b as viewed from the Z direction. The inner portion 22a and the outer portion 22b each have a frame shape (here, a rectangular frame shape) as viewed from the Z direction.

[0041] The end portion of the separator 14 may be sandwiched and held between the sealing material 21 and the spacer 22. The separator 14 can be fixed by being welded to at least one of the sealing material 21 and the spacer 22 at its end portion.

[0042] The outer ends of the outer parts 21b of the seal materials 21 and the outer ends of the outer parts 22b of the spacers 22 are welded together to form a welded portion 23. That is, the sealing body 20 includes the welded portion 23 formed by welding the outer parts 21b of the seal materials 21 and the outer parts 22b of the spacers 22 together. The welded portion 23 has a frame shape (here, a rectangular frame shape) surrounding the electrode stack 10 when viewed from the Z direction, and forms the outer periphery of the sealing body 20. Therefore, the outer surface 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 extending along the Z direction. The spacers 22 may not be welded to the sealing material 21 at least in the inner parts 21a of the sealing materials 21 adjacent to each other in the Z direction.

[0043] A conductive member (not shown) may be laminated on the other surface 15b of the current collector 15 of the negative terminal electrode 12 and on a portion of the one surface 15a of the current collector 15 of the positive terminal electrode 13 that is exposed from the sealing body 20 (i.e., a portion where the seal material 21 is not provided when viewed from the Z direction). The conductive members are electrically connected to the current collector 15 of the negative terminal electrode 12 and the current collector 15 of the positive terminal electrode 13, respectively. The conductive members are interposed between adjacent power storage modules 1, and function as terminals for extracting current from the power storage modules 1. The conductive members can be used to electrically connect multiple power storage modules 1. Multiple power storage modules 1 may be arranged in series via the conductive members.

[0044] Further, the conductive member may also be used as a member for applying a restraining load to the electrode laminate 10. That is, when a restraining member (not shown) for restraining the power storage module 1 from the Z direction is arranged, a restraining load may be applied to the electrode laminate 10 via the conductive member. Further, a cooling flow path may be formed in the conductive member. By flowing a cooling medium through the cooling flow path formed in the conductive member, the power storage module 1 can be cooled. Further, members (not shown) configured integrally or separately with the conductive member may be arranged on both sides of the sealing body 20 in the Z direction, and a restraining load may be applied to the sealing body 20 via the members.

[0045] FIG. 3 is a schematic cross-sectional view showing an enlarged part of the power storage module shown in FIG. 1. In FIGS. 1 and 3, the separator 14 is provided between the surface of the spacer 22 on the negative electrode active material layer 17 side and the sealing material 21 facing the surface, but is not limited thereto as long as insulation between the positive electrode active material layer 16 and the negative electrode active material layer 17 can be ensured.

[0046] As shown in FIGS. 1 to 3, when viewed from the Z direction, the inner edge 22e of the spacer 22 (that is, a part inside the inner part 22a) 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. Thereby, the spacer 22 includes an overlapping portion 22r that overlaps the negative electrode active material layer 17 when viewed from the Z direction, and a non-overlapping portion 22p that does not overlap the sealing material 21 and the negative electrode active material layer 17 when viewed from the Z direction.

[0047] Among the plurality of spacers 22, the spacer 22 at the outermost part in the Z direction (here, the most positive electrode terminal electrode 13 side) may or may not be sandwiched via the separator 14 between the current collector 15 of the positive electrode terminal electrode 13 and the negative electrode active material layer 17 facing the current collector 15 in the overlapping portion 22r. More specifically, the overlapping portion 22r of the outermost spacer 22 in the Z direction may or may not be in contact with one surface 15a of the current collector 15 and the separator 14 facing the one surface 15a.

[0048] Here, in the present embodiment, the thickness Ts of the spacer 22 in the Z direction is made thinner than the thickness Tp of the positive electrode active material layer 16 in the Z direction. As a result, among the plurality of spacers 22, the spacers 22 other than the outermost spacer 22 in the Z direction (the intermediate spacers 22) are configured not to contact the current collector 15 of the adjacent bipolar electrode 11 in the overlapping portion 22r. In other words, an internal space S is interposed between the intermediate spacer 22 and one surface 15a of the current collector 15 of the bipolar electrode adjacent thereto.

[0049] Further, the negative electrode active material layer 17 includes a rectangular first portion 171 that overlaps the positive electrode active material layer 16 when viewed from the Z direction, and a frame-shaped (here, rectangular frame-shaped) second portion 172 that is located outside the outer edge 16e of the positive electrode active material layer 16 when viewed from the Z direction and includes the outer edge 17e of the negative electrode active material layer 17. In the present embodiment, the thickness T1 of the first portion 171 in the Z direction and the thickness T2 of the second portion 172 in the Z direction are the same as each other. However, in the first portion 171, the negative electrode active material layer 17 may be recessed so that the positive electrode active material layer 16 enters along the Z direction, whereby the thickness T2 of the second portion 172 may be made thicker than the thickness T1 of the first portion 171.

[0050] Further, the current collector 15 includes a first region 151 that does not overlap the negative electrode active material layer 17 and the sealing material 21 when viewed from the Z direction, and a second region 152 that overlaps the negative electrode active material layer 17 and does not overlap the positive electrode active material layer 16 when viewed from the Z direction. The first region 151 is a region between the outer edge 17e of the negative electrode active material layer 17 and the inner edge 21e of the sealing material 21. That is, the first region 151 coincides with the non-overlapping portion 22p of the spacer 22 when viewed from the Z direction.

[0051] The second region 152 is the region between the outer edge 16e of the positive electrode active material layer 16 and the outer edge 17e of the negative electrode active material layer 17. The second region 152 overlaps with the overlapping portion 22r of the spacer 22 when viewed from the Z direction. In the present embodiment, the width W1 of the first region 151 when viewed from the Z direction is made narrower than the width W2 of the second region 152 when viewed from the Z direction. As described above, since the spacer 22 includes the overlapping portion 22r, the spacer 22 is disposed between the current collectors 15 adjacent to each other in the Z direction in the first region 151.

[0052] Further, the electrode laminate 10 includes a first laminated portion 101 in which the negative electrode active material layer 17 and the positive electrode active material layer 16 overlap when viewed from the Z direction, and a second laminated portion 102 including a portion where the negative electrode active material layer 17 and the overlapping portion 22r overlap when viewed from the Z direction. The second laminated portion 102 coincides with the region combining the first region 151 and the second region 152 when viewed from the Z direction. The sealing body 20 includes a first sealing portion 201 where the sealing material 21 and the spacer 22 overlap when viewed from the Z direction. The first sealing portion 201 does not overlap with the overlapping portion 22r and the non-overlapping portion 22p of the spacer 22 when viewed from the Z direction. In the present embodiment, the thicknesses in the Z direction are thin in the order of the first laminated portion 101, the second laminated portion 102, and the first sealing portion 201. That is, the thickness of the second laminated portion 102 in the Z direction is thinner than the thickness of the first laminated portion 101 in the Z direction, and the thickness of the first sealing portion 201 in the Z direction is thinner than the thickness of the second laminated portion 102 in the Z direction.

[0053] Furthermore, at the corner of the portion of the sealing body 20 that is outside the outer edge 15e of the current collector 15 when viewed from the Z direction in the first sealing portion 201 (that is, the portion constituted by the outer portion 21b of the sealing material 21 and the outer portion 22b of the spacer 22 and including the welding portion 23), an inclined surface 20p is formed. In the present embodiment, the outer surface of the outer portion 21b of the sealing material 21 provided at the peripheral edge portion 15c of the current collector 15 of the positive electrode terminal electrode 13 is the inclined surface 20p. The inclined surface 20p is inclined such that the thickness of the first sealing portion 201 (sealing material 21) gradually decreases from the inside to the outside of the first sealing portion 201 (sealing material 21).

[0054] Next, an example of a manufacturing method for the above-described power storage module 1 will be described. FIG. 4 is a flowchart showing the manufacturing method for the power storage module according to the present embodiment. FIG. 5 is a schematic cross-sectional view showing one step of the flowchart shown in FIG. 4. As shown in FIGS. 4 and 5, in this manufacturing method, first, a battery body 1A is prepared (step S101, first step). Step S101 will be described in more detail.

[0055] The battery body 1A includes the above-described electrode laminate 10 and a sealing body 20A that serves as the basis for the above-described sealing body 20. The sealing body 20A is different from the above-described sealing body 20 in that it does not include the welding portion 23. That is, the sealing body 20A becomes the sealing body 20 when its end is welded in a later step S105. Further, in the sealing body 20A, the sealing material 21 is composed of a sealing material 71 and a sealing material 72. Here, the sealing material 71 is welded to one surface 15a of the current collector 15, and the sealing material 72 is welded to the other surface 15b of the current collector 15.

[0056] Such a battery body 1A is configured by preparing a unit including the negative terminal electrode 12 and the sealing material 21, a unit including the bipolar electrode 11 and the sealing material 21, and a unit including the positive terminal electrode 13 and the sealing material 21, and laminating these units via the spacer 22 and the separator 14. Each unit is formed by welding the sealing material 71 and the sealing material 72 (i.e., the sealing material 21) to one surface 15a and the other surface 15b of the current collector 15 of each electrode, respectively, to assemble them.

[0057] Note that the spacer 22 may be temporarily welded to the sealing material 21, for example, to form an assembly. Also, at the time of step S101, the sealing material 71 and the sealing material 72 are not integrated, and a gap corresponding to the outer portion 21b of the sealing material 21 may be formed between them at a portion corresponding to the thickness of the current collector 15. As described above, the battery body 1A is provided with a sealing material 21 composed of an inner portion 21a overlapping the peripheral edge portion 15c of the electrode (of the current collector 15) and an outer portion 21b located outside the peripheral edge portion 15c for each of the plurality of electrodes laminated along the Z direction.

[0058] In the subsequent step, while restraining the battery body 1A along the Z direction using a predetermined restraining jig, the ends of the outer portions 22b of each of the plurality of sealing materials 21 of the battery body 1A (and the ends of the outer portions 22b of each of the plurality of spacers 22) are cut along the Z direction (step S102). Thereby, the ends of the plurality of sealing materials 21 (that is, the outer surface of the sealing body 20A) are aligned. Note that in step S102, a restraining jig similar to the restraining jig 50 described later may be used, or a restraining jig different from the restraining jig 50 may be used.

[0059] Subsequently, the battery body 1A is restrained along the Z direction using the restraining jig 50 (step S103, second step). The restraining jig 50 includes a pair of restraining plates 51, 52 and a resin member 55 formed of a heat-resistant resin and disposed between the pair of restraining plates 51, 52. The resin member 55 includes a pair of elastic members 53, 54. The pair of restraining plates 51, 52 are formed in a flat plate shape from a metal such as stainless steel, for example. The elastic members 53, 54 are each formed of a resin material that is more easily elastically deformed (that is, elastic) than the metal constituting the restraining plates 51, 52, such as silicone rubber, for example. Also, the elastic members 53, 54 may be formed of a material having a lower thermal conductivity than the metal constituting the restraining plates 51, 52.

[0060] The elastic member 53 is disposed on the side of one of the pair of restraint plates 51 and 52, i.e., on the side of the restraint plate 51. A part of the elastic member 53 may be embedded in the restraint plate 51, and the remaining part of the elastic member 53 may protrude from the surface of the restraint plate 51. The elastic member 54 is disposed on the side of the other of the pair of restraint plates 51 and 52, i.e., on the side of the restraint plate 52. The elastic member 54 is formed in a flat plate shape. The elastic member 54 may be, for example, entirely embedded in the restraint plate 52 so that the surface of the elastic member 54 and the surface of the restraint plate 52 are flush with each other.

[0061] In step S103, the battery body 1A is restrained using the restraint jig 50 as described above. That is, in step S103, the pair of restraint plates 51 and 52 are arranged so as to sandwich the battery body 1A along the Z direction, and the elastic member 53 is arranged so as to be interposed between one of the pair of restraint plates 51 and the outermost sealing material 21 in the Z direction (here, the sealing material 21 of the unit including the positive terminal electrode 13), and the elastic member 54 is arranged so as to be interposed between the other of the pair of restraint plates 52 and the outermost sealing material 21 in the direction opposite to the Z direction (here, the sealing material 21 of the unit including the negative terminal electrode 12). The battery body 1A is restrained along the Z direction by the pair of restraint plates 51 and 52 and the elastic members 53 and 54.

[0062] In particular, in step S103, the resin member 55 is arranged such that the elastic members 53 and 54 overlap the outer portion 21b of the sealing material 21 along the Z direction. In the present embodiment, the elastic members 53 and 54 are respectively arranged so as to overlap from the inner portion 21a to the outer portion 21b of the sealing material 21 along the Z direction. In that state, by restraining the battery body 1A with the pair of restraining plates 51 and 52 and the elastic members 53 and 54, the outer portion 21b is pressed by the elastic members 53 and 54 (here, the inner portion 21a is also pressed). At this time, the amount of elastic deformation of the elastic member 53 is different between the portion pressing the inner portion 21a and the portion pressing the outer portion 21b (the portion pressing the inner portion 21a is relatively larger). As a result, the sealing body 20A is constricted at a position corresponding to the outer portion 21b where the current collector 15 is not interposed in the Z direction, and the gap corresponding to the thickness of the current collector 15 between the sealing material 71 and the sealing material 72 is reduced. As a result, the sealing body 20A is constricted such that the thickness of the sealing body 20A in the Z direction gradually decreases toward the outside of the sealing body 20A, and an inclination that will later become the inclined surface 20p is formed.

[0063] Note that when viewed from the Z direction, the battery body 1A includes, in order from the inside, a formed portion 111 in which the positive electrode active material layer 16 and the negative electrode active material layer 17 are formed on the current collector 15, an unformed portion 112 in which the positive electrode active material layer 16 and the negative electrode active material layer 17 are not formed on the current collector 15, a welded portion 113 where the sealing material 21 and the current collector 15 are welded, and a resin laminated portion 114 where the current collector 15 is not interposed. In step S103, the pair of restraining plates 51 and 52 are brought into contact with the formed portion 111 whose both end faces in the Z direction are the surfaces of the current collector 15, and while the elastic members 53 and 54 are brought into contact with the welded portion 113 and the resin laminated portion 114 whose both end faces in the Z direction are the surfaces of the sealing material 21, the battery body 1A is restrained. At this time, in the unformed portion 112, the battery body 1A and the restraining jig 50 do not have to be in contact. Also, the sealing body 20A may be slightly protruded outside the restraining jig 50 in a state of being restrained by the restraining jig 50 in step S103. That is, the end portions of the outer portion 21b of the sealing material 21 (and the outer portion 22b of the spacer 22) may protrude from the restraining jig 50.

[0064] In the subsequent process, while maintaining the state in which the battery body 1A is constrained by the restraint jig 50, the ends of the outer portions 21b of the plurality of sealing materials 21 of the battery body 1A (and the ends of the outer portions 22b of the plurality of spacers 22) are cut again along the Z direction (process S104). Thereby, even if there is variation in the positions of the ends of the outer portions 21b of the plurality of sealing materials 21 (and the ends of the outer portions 22b of the plurality of spacers 22)) due to the restraint by the restraint jig 50, the ends are aligned.

[0065] Subsequently, by welding the plurality of sealing materials 21 to each other, the sealing body 20 is formed from the sealing body 20A, and the electrode laminate 10 is sealed by the sealing body 20 to form the power storage module 1 from the battery body 1A (process S105, the third process). More specifically, in process S105, with the battery body 1A constrained by the restraint jig 50, the heater 60 is disposed so as to face the outer portion 21b while being separated from the outer portion 21b of the plurality of sealing materials 21, and the heater 60 heats the ends of the outer portion 21b of the plurality of sealing materials 21 and the ends of the outer portion 22b of the spacer 22 to weld them to each other. That is, in the present embodiment, the outer portions 21b of the sealing material 21 are welded to each other via the outer portions 22b of the spacer 22.

[0066] Here, as shown in FIG. 6, the outer portion 21b of the sealing material 21 has a rectangular frame shape having four ends 211 to 214 when viewed from the Z direction. Each of the four ends 211 to 214 corresponds to each of the four side portions constituting the rectangle. And in the present embodiment, in process S105, the two ends 212 and 213 that share one corner (that is, extend in an L shape) among the four ends 211 to 214 of the outer portion 21b are heated collectively.

[0067] Therefore, in step S105, the plurality of heaters 60 are arranged along each of two end portions 212 and 213 that share one corner of the outer portion 21b. The end portion 212 extends along the X direction (the second direction intersecting the first direction) that intersects the Z direction. Thus, in the end portion 212, the plurality of heaters 60 are arranged to be aligned along the X direction. Further, the end portion 213 extends along the Y direction (the third direction intersecting the first and second directions) that intersects the Z direction. Thus, in the end portion 213, the plurality of heaters 60 are arranged to be aligned along the Y direction. Furthermore, each of the plurality of heaters 60 is in a long shape and is arranged such that its longitudinal direction is along the Z direction.

[0068] By performing the above step S105, the sealing body 20 including the welded portion 23 is formed from the sealing body 20A, the electrode laminate 10 is sealed by the sealing body 20, and the power storage module 1 is obtained from the battery body 1A. In the power storage module 1, the inclined surface 20p of the sealing body 20 is formed by the pressing of the elastic member 53. Note that after the above steps, other steps such as a step of injecting an electrolytic solution into the internal space S of the power storage module 1 and a step of sealing the injection port of the electrolytic solution thereafter may be further performed.

[0069] As described above, in the method for manufacturing a power storage module according to the present embodiment, first, the battery body 1A is prepared. The battery body 1A has a sealing material 21 provided at the peripheral edge portion 15c of each of a plurality of electrodes laminated along the Z direction (of the current collector 15). Each of the plurality of sealing materials 21 includes an inner portion 21a that overlaps the peripheral edge portion 15c of the electrode and an outer portion 21b that is located outside the peripheral edge portion 15c of the electrode. Further, each of the plurality of sealing materials 21 includes a sealing material 71 and a sealing material 72 provided on each of one surface 15a and the other surface 15b of the current collector 15.

[0070] Therefore, in the battery body 1A, a gap corresponding to the thickness of the current collector 15 may be formed between the outer portions of the sealing materials 71 and 72 adjacent to each other in the stacking direction through the current collector 15. In contrast, in this manufacturing method, in a subsequent step, the battery body 1A is constrained using the constraining jig 50. At this time, a pair of constraining plates 51 and 52 of the constraining jig 50 are arranged so as to sandwich the battery body 1A, and a resin member 55 (in this embodiment, the elastic member 53) having higher elasticity than the constraining plates 51 and 52 in the constraining jig 50 is interposed between the constraining plate 51 and the outermost sealing material 21. Thereby, while the resin member 55 is elastically deformed, the laminated portion of the outer portion 21b is pressed to apply a constraining force in the stacking direction, and the gap between the adjacent sealing materials 71 and 72 through the current collector 15 can be reduced. In that state, the ends of the outer portions 21b of the plurality of sealing materials 21 are welded to each other using a non-contact heater 60. Thereby, the void remaining inside the welded portion between the adjacent sealing materials 71 and 72 through the current collector 15 is reduced, and the occurrence of defective products is suppressed.

[0071] Here, when constraining the battery body 1A, if only a pair of constraining plates 51 and 52 that are relatively difficult to elastically deform are used, sufficient constraining force may not be applied to the outer portion 21b of the sealing material 21 where the current collector 15 is not interposed, and there is a possibility that variations may occur in the positions of the ends of the outer portions 21b and 22b of the sealing material 21 and the spacer 22, respectively. Further, since the relatively rigid constraining plates 51 and 52 come into contact with the sealing material 21, there is also a possibility that the sealing material 21 may be torn by the constraining force from the constraining plates 51 and 52. In this case, variations also occur in the welding cost during welding using the heater 60, and there is a possibility that defective products may similarly occur.

[0072] On the other hand, in the manufacturing method of the power storage module according to the present embodiment, in addition to the pair of restraint plates 51 and 52, a resin member 55 (elastic member 53 in the present embodiment) that is easily elastically deformed is disposed so as to be interposed between the restraint plate 51 and the sealing material 21, and the battery body 1A is restrained by these. As a result, it becomes possible to apply a sufficient restraining force to the outer portion 21b of the sealing material 21 by the resin member 55, and it is possible to suppress variations in the positions of the ends of the outer portions 21b and 22b of the sealing material 21 and the spacer 22, respectively. Therefore, it is possible to suppress variations in the welding allowance during welding using the heater 60, and thus suppress the occurrence of defective products.

[0073] Further, the resin member 55 includes the elastic member 53. In step S103, the resin member 55 is disposed so that the elastic member 53 overlaps the outer portion 21b when viewed from the Z direction, thereby pressing the outer portion 21b by the elastic member 53. As a result, it becomes possible to surely apply a restraining force to the outer portion 21b.

[0074] In the manufacturing method of the power storage module according to the present embodiment, in step S105, a plurality of long heaters 60 may be arranged such that the longitudinal direction of the heater 60 is along the Z direction and along at least one of the ends (ends 211 to 214) of the outer portion 21b of the sealing material 21, and the plurality of heaters 60 may heat the end of the outer portion 21b of the sealing material 21 (and the end of the outer portion 22b of the spacer 22).

[0075] In this way, when using a plurality of heaters 60 arranged along the end portion to be welded in the outer portion 21b of the sealing material 21, a short heater is used in the direction along the end portion, and current is passed through the short heaters in parallel for heating. Therefore, compared with the case of using one long heater extending along the end portion, it is possible to suppress an increase in the resistance value and suppress an increase in the required applied voltage (that is, it is possible to avoid an increase in voltage). Further, in this case, by increasing or decreasing the number of heaters 60, it becomes possible to flexibly cope with heating targets of a plurality of sizes.

[0076] Furthermore, in the method for manufacturing a power storage module according to the present embodiment, the outer portion 21b of the sealing material 21 has a rectangular frame shape having four end portions 211 to 214 when viewed from the Z direction. In step S105, a plurality of heaters 60 are arranged along two end portions 212 and 213 that share one corner of the outer portion 21b, and the two end portions 212 and 213 are heated collectively. Therefore, at the corner formed by the two end portions 212 and 213, the melting of the sealing material 21 and the spacer 22 can be made uniform.

[0077] The above embodiments illustrate one aspect of the method for manufacturing a power storage module according to the present invention. Therefore, the method for manufacturing a power storage module according to the present invention is not limited to the above embodiments and can be arbitrarily modified. Subsequently, modification examples will be described.

[0078] FIG. 7 is a schematic cross-sectional view showing a step of the method for manufacturing a power storage module according to a modification example. As shown in FIG. 7, in this modification example, in step S103, a restraint jig 50A is used instead of the restraint jig 50. The restraint jig 50A is different from the restraint jig 50 in that it includes a resin member 55A instead of the resin member 55. The resin member 55A has a flat heat-resistant member (first heat-resistant member) 56, an elastic member 57, and a flat heat-resistant member (second heat-resistant member) 58. The heat-resistant member 56 and the elastic member 57 are arranged on the side of one of the pair of restraint plates 51 and 52, which is the restraint plate 51. The heat-resistant member 56 may be, for example, entirely embedded in the restraint plate 51 so that the surface of the heat-resistant member 56 and the surface of the restraint plate 51 are flush.

[0079] The elastic member 57 is disposed on the side opposite to the restraint plate 51 in the heat-resistant member 56. That is, the heat-resistant member 56 is disposed between the elastic member 57 and the restraint plate 51. The elastic member 57 is in contact with the heat-resistant member 56 and may be joined to the heat-resistant member 56. The heat-resistant member 58 is disposed on the side of the other restraint plate 52 among the pair of restraint plates 51, 52. The heat-resistant member 58 is formed in a flat plate shape. The heat-resistant member 58 may be, for example, entirely embedded in the restraint plate 52 so that the surface of the heat-resistant member 58 and the surface of the restraint plate 52 are flush. The heat-resistant members 56, 58 are made of a resin material such as bakelite, for example, and the elastic member 57 is made of a resin material different from the materials of the heat-resistant members 56, 58 such as silicone rubber, for example. The resin material constituting the elastic member 57 may be a material that is more easily elastically deformed (elastic) than the resin materials constituting the heat-resistant members 56, 58. Further, the thermal conductivities of the heat-resistant members 56, 58 and the elastic member 57 are all lower than that of the restraint plate 51.

[0080] In step S103, a pair of restraint plates 51, 52 are arranged so as to sandwich the battery body 1A along the Z direction, and the heat-resistant member 56 and the elastic member 57 are arranged so as to be interposed between one of the pair of restraint plates 51, 52, i.e., the restraint plate 51, and the outermost sealing material 21 in the Z direction (here, the sealing material 21 of the unit including the positive terminal electrode 13), and the heat-resistant member 58 is arranged so as to be interposed between the other restraint plate 52 of the pair of restraint plates 51, 52 and the outermost sealing material 21 in the direction opposite to the Z direction (here, the sealing material 21 of the unit including the negative terminal electrode 12). The battery body 1A is restrained along the Z direction by the pair of restraint plates 51, 52, the heat-resistant member 56, the elastic member 57, and the heat-resistant member 58. In particular, in step S103, the resin member 55A can be arranged such that the heat-resistant member 56 is located on the side of the restraint plate 51 and the elastic member 57 is located on the side of the sealing material 21. At this time, by arranging the resin member 55A such that the elastic member 57 overlaps with the outer portion 21b of the sealing material 21 when viewed from the Z direction, the outer portion 21b is pressed by the elastic member 57. Further, the heat-resistant member 58 is arranged so as to sandwich the battery body 1A along the Z direction together with the heat-resistant member 56 and the elastic member 57 and so as to overlap with the sealing material 21 along the Z direction.

[0081] In this case, since the elastic member 57 of the resin member 55A, which is the portion of the restraining jig 50A that contacts the sealing body 20A, and the heat-resistant member 56, which is the portion that supports the elastic member 57 of the resin member 55A, are made of different materials, the degree of freedom in designing the heat-resistant member 56 and the elastic member 57 is improved. That is, for example, by applying relatively hard rubber to the heat-resistant member 56 and relatively soft rubber to the elastic member 57, and changing their respective thicknesses, it becomes possible to adjust the amount of deformation of each member during restraint. As a result, it is possible to efficiently fill the gap between the adjacent sealing materials 71 and 72 via the current collector 15, thereby improving the sealing performance.

[0082] Also, in the above-described embodiment, in step S105, a plurality of heaters 60 are arranged along two end portions 212 and 213 that share one corner of the outer portion 21b of the sealing material 21 among the four end portions 211 to 214, and heating is performed collectively at these two end portions 212 and 213. However, in step S105, a plurality of heaters 60 may be arranged along three or more end portions (for example, all of the end portions 211 to 214) of the outer portion 21b and collective heating may be performed. Alternatively, in step S105, heating may be performed separately at each of the plurality of end portions 211 to 214. Further, in the illustrated example, a heater 60 having a circular cross-section is used, but a heater 60 having an arbitrary cross-sectional shape such as a rectangular shape may be used. Furthermore, the restraining jig 50 may not have the elastic member 54.

Explanation of Reference Numerals

[0083] 1... Power storage module, 1A... Battery body, 10... Electrode laminate, 11... Bipolar electrode (electrode), 12... Negative terminal electrode (electrode), 13... Positive terminal electrode (electrode), 20, 20A... Sealing body, 21... Sealing material, 21a... Inner portion, 21b... Outer portion, 22... Spacer, 23... Welded portion, 50, 50A... Restraining jig, 51, 52... Restraining plates, 55, 55A... Resin members, 53, 57... Elastic members, 56... Heat-resistant member (first heat-resistant member), 58... Heat-resistant member (second heat-resistant member), 60... Heater, 71, 72... Sealing materials.

Claims

1. A method for manufacturing a power storage module in which a sealing body is provided so as to surround an electrode when viewed from a first direction, comprising: a first step of preparing a battery body in which a sealing material composed of an inner portion overlapping the peripheral edge of the electrode and an outer portion located outside the peripheral edge is provided for each of the plurality of electrodes laminated along the first direction; a second step of restraining the battery body along the first direction using a restraining jig after the first step; a third step of forming the sealing body by welding and integrating the outer portions of the plurality of sealing materials with each other after the second step; characterized by the restraining jig including a pair of restraining plates and a resin member more elastic than the restraining plates; in the second step, arranging the pair of restraining plates so as to sandwich the battery body along the first direction, and arranging the resin member so as to be interposed between one of the pair of restraining plates and the outermost sealing material in the first direction and so as to overlap the outer portion along the first direction; in the third step, arranging a heater so as to face the outer portion while being separated from the outer portion in a state where the battery body is restrained by the restraining jig, and heating and welding the ends of the outer portions of the plurality of sealing materials by the heater to form the sealing body; a method for manufacturing a power storage module.

2. The resin member includes an elastic member, and in the second step, the resin member is arranged so that the elastic member overlaps the outer portion when viewed from the first direction, and the outer portion is pressed by the elastic member. The method for manufacturing a power storage module according to claim 1.

3. The resin member includes a flat first heat-resistant member, and the first heat-resistant member is arranged between the one restraining plate and the elastic member. The method for manufacturing a power storage module according to claim 2.

4. The resin member includes a flat second heat-resistant member, and in the second step, the second heat-resistant member is arranged so as to sandwich the battery body along the first direction together with the first heat-resistant member and the elastic member and so as to overlap the sealing material along the first direction. The method for manufacturing a power storage module according to claim 3.

5. In the third step, a plurality of elongated heaters are arranged such that the longitudinal direction of the heater is along the first direction and the heaters are arranged side by side along the ends of the outer portion. The method for manufacturing a power storage module according to any one of claims 1 to 4.

6. The outer portion has a rectangular frame shape having four end portions when viewed from the first direction, In the third step, a plurality of the heaters are arranged so as to be aligned along two of the end portions that share one corner portion of the outer portion, and the two end portions are heated together. The method for manufacturing a power storage module according to claim 5.

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