Power storage module and method for manufacturing power storage module

Abstract

A power storage module is provided with an electrode laminate, a sealing body provided on the electrode laminate, and an injection resin part joined to the sealing body. Each of the plurality of electrodes includes a current collector having a rectangular shape when viewed from the first direction. The closed body includes: a welded end portion in which the outer peripheral edges of the plurality of frame-shaped members are welded to each other; and a plurality of communication holes that communicate with the outside of the injection port surface of the welding end. The injection resin part includes: a main body part partially covering the injection port surface; and a plurality of protruding frame portions that surround openings connected to each of the plurality of communication holes when viewed from a second direction intersecting the injection port surface.

Description

Technical Field

[0001] The present disclosure relates to a power storage module and a method for manufacturing the same. Background Art

[0002] Patent document 1 discloses a power storage module. The power storage module includes an electrode stack and a frame that surrounds the electrode stack over the entire circumference when viewed from the stacking direction. The electrode stack includes a plurality of electrode plates stacked with separators therebetween. The frame has a through hole that penetrates into an internal space formed between adjacent electrode plates. The through hole functions as a liquid injection port for injecting electrolyte into the internal space. Such a frame is, for example, an injection resin body formed by injection molding.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-86674 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] As described above, in the structure in which the injection resin body surrounding the electrode stack is provided with a liquid injection port, when manufacturing a storage device having electrodes with a large area, it is expected that the size of the storage module will become larger. In addition, in this case, the size of the required mold will also become larger, which may lead to an increase in production costs.

[0008] The present disclosure provides a power storage module and a method for manufacturing the same, which can suppress an increase in the size of the power storage module and the size of a mold required for manufacturing the power storage module.

[0009] Solutions for solving problems

[0010] The storage module involved in one aspect of the present disclosure comprises: an electrode stack, which includes a plurality of electrodes stacked along a first direction, and includes a sealing body arranged in a manner to form an internal space between adjacent electrodes and to seal the internal space; and an injection resin portion, which is joined to the sealing body. Each of the plurality of electrodes includes a collector that is rectangular when viewed from the first direction. The sealing body includes a welded end portion formed by welding the outer peripheries of a plurality of frame-shaped members that are interposed between the plurality of collectors and stacked in the first direction. The welded end portion has four outer side surfaces that surround the plurality of collectors and extend along the first direction when viewed from the first direction. The sealing body has: a first end surface and a second end surface, which are two end surfaces of the electrode stack in the first direction; an injection port surface, which is one of the four outer side surfaces and is joined to the injection resin portion; and a plurality of connecting holes, which connect the outer side of the injection port surface with each of the plurality of internal spaces. The injection resin part includes: a main body part having a plurality of openings connected to the plurality of communication holes respectively and partially covering the injection port surface; a first hanging part connected to the main body part and partially covering the first end surface; and a second hanging part connected to the main body part and partially covering the second end surface. The main body part includes a plurality of protruding frame parts protruding in a second direction intersecting the injection port surface, and the plurality of protruding frame parts surround the plurality of openings respectively when viewed from the second direction.

[0011] In the above-mentioned power storage module, a connecting hole that penetrates to the internal space is provided at the welding end of the closing body formed on the outer periphery of the electrode stack. An injection resin part having a frame part surrounding the connecting hole is joined to the closing body. The injection resin part has: a main body part, which covers the injection port surface that is one of the four outer side surfaces forming the welding end; a first overhanging part, which extends from the main body part to the first end surface of the electrode stack; and a second overhanging part, which extends from the main body part to the second end surface of the electrode stack. In this way, since the injection resin part is only provided on one of the four outer side surfaces, the size of the power storage module can be suppressed from being enlarged. In addition, the injection resin part does not require a mold of a size that surrounds the entire circumference of the electrode stack, and can be formed by a mold of a size that can partially cover the injection port surface. Therefore, the size of the mold required for manufacturing can be suppressed from being enlarged.

[0012] Alternatively, an example of an injected resin portion may include a first thin-walled portion connected to the main body portion and joined to the injection port surface along the injection port surface from the main body portion, wherein the thickness of the first thin-walled portion in the second direction is smaller than the thickness of the main body portion in the second direction.

[0013] Alternatively, an example of an injected resin portion may include a second thin-walled portion connected to the first overhanging portion, joined to the first end surface along the first end surface from the first overhanging portion, and having a thickness in the first direction that is smaller than a thickness in the first overhanging portion in the first direction.

[0014] Alternatively, an example current collector may include: a first region, which is disposed in the center of the current collector when viewed from a first direction and has an active material layer formed thereon; and a second region, which is frame-shaped and is located to the outside of the first region, wherein the frame-shaped member includes: a plurality of sealants, which are frame-shaped and are disposed in the second region of each of the plurality of current collectors; and a plurality of spacers, which are disposed between sealants adjacent to each other in the first direction and, together with the plurality of sealants, define an internal space between the current collectors.

[0015] The manufacturing method of the storage battery module involved in one aspect of the present disclosure comprises: a process of preparing an electrode stack, wherein the electrode stack includes a plurality of electrodes stacked along a first direction, and two end faces in the first direction are used as a first end face and a second end face; a process of setting a welding end portion in the electrode stack in a manner so that an internal space is formed between adjacent electrodes; and a process of setting an injection resin portion at the welding end portion. Each of the plurality of electrodes includes a collector that is rectangular when viewed from the first direction. The process of setting the welding end portion includes a process of welding the outer peripheries of a plurality of frame-shaped members that are interposed between the plurality of collectors and stacked in the first direction to each other. One of the four outer side faces of the welding end portion on the side opposite to the internal space, namely, the injection port face, has a plurality of connecting holes that are connected to each of the plurality of internal spaces. The process of setting up the injection resin part includes: a process of assembling a mold that partially covers the injection port surface to the electrode stack in such a manner that a continuous molding space is formed between a main body area including a plurality of connecting holes in the injection port surface, a first overhang area connected to the main body area and partially extending on the first end surface of the electrode stack, and a second overhang area connected to the main body area and partially extending on the second end surface of the electrode stack; and a process of injecting resin into the molding space of the mold assembled on the electrode stack.

[0016] In the manufacturing method of the above-mentioned storage battery module, a storage battery module can be manufactured in which a connecting hole that penetrates to the internal space is provided at the welding end of the closing body formed on the outer periphery of the electrode stack. An injection resin part having a frame part surrounding the connecting hole is joined to the closing body. In the process of assembling the mold to the electrode stack, the mold is assembled in a manner so that a forming space is formed between a main body area extending from one of the four outer sides forming the welding end, that is, the injection port surface, a first overhanging area extending from the main body to the first end face of the electrode stack, and a second overhanging area extending from the main body to the second end face of the electrode stack. In this case, a mold of a size that surrounds the entire circumference of the electrode stack is not required, and the injection resin part can be formed by a mold of a size that can partially cover one outer side of the electrode stack. Therefore, the size of the mold required for manufacturing can be suppressed from being enlarged. In addition, the size of the manufactured storage battery module can be suppressed from being enlarged.

[0017] In one example, in the process of assembling the mold, a first thin-walled space connected to the forming space and extending from the forming space along the injection port surface is formed, and the thickness of the first thin-walled space in a second direction intersecting the injection port surface is smaller than the thickness of the forming space in the main body area in the second direction.

[0018] In one example, in the process of assembling the mold, a second thin-walled space is formed that is connected to the forming space and extends from the first overhang area along the first end surface, and the thickness of the second thin-walled space in the first direction is smaller than the thickness of the forming space in the first overhang area in the first direction.

[0019] Alternatively, the current collector may comprise: a first region, which is arranged in the center of the current collector when viewed from a first direction and has an active material layer formed thereon; and a second region, which is frame-shaped and is located on the outside of the first region, wherein the frame-shaped member comprises: a plurality of sealants, which are frame-shaped and are arranged in the second region of each of the plurality of current collectors; and a plurality of spacers, which are located between the sealants adjacent to each other in the first direction and, together with the plurality of sealants, define an internal space between the current collectors, wherein the electrode stack comprises a plurality of insulators arranged between the plurality of current collectors, wherein the outer edges of the plurality of insulators are respectively arranged between the plurality of sealants and the plurality of spacers, and in the step of assembling the mold, the mold is clamped to clamp a region of the electrode stack where the plurality of current collectors, the plurality of sealants, the plurality of spacers and the plurality of insulators are repeated when viewed from the first direction.

[0020] Alternatively, an example mold includes a first mold and a second mold that clamp the electrode stack from a first direction, and the surface roughness of the first mold's surface that abuts the electrode stack and the surface roughness of the second mold's surface that abuts the electrode stack are greater than the surface roughness of the forming surface of the mold's forming space.

[0021] Effects of the Invention

[0022] According to the present disclosure, it is possible to provide a power storage module and a method for manufacturing the power storage module, which can suppress an increase in the size of a mold required for manufacturing and the size of the power storage module. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. 1 is a schematic top view of an example of a power storage module.

[0024] Figure 2 This is a schematic cross-sectional view of an example of a power storage module.

[0025] Figure 3 FIG. 1 is a schematic front view of an example of a power storage module.

[0026] Figure 4 This is a schematic cross-sectional view of an example of a power storage module.

[0027] Figure 5 This is a schematic cross-sectional view of an example of a power storage module.

[0028] Figure 6 This is a schematic cross-sectional view of an example of a power storage module.

[0029] Figure 7 This is a flow chart showing an example of a method for manufacturing a power storage module.

[0030] Figure 8 It is a plan view showing the position of a mold mounted on an example power storage module.

[0031] Fig. 9 This is a schematic cross-sectional view of an example mold.

[0032] Fig.10 This is a schematic cross-sectional view of an example mold.

[0033] Fig.11 This is a schematic cross-sectional view of an example of a mold.

[0034] Fig.12 It is a diagram showing the contact surface of the mold with respect to the electrode stack.

[0035] Fig.13 FIG. 1 is a schematic top view of another example of a power storage module.

[0036] Fig.14 yes Fig.13 A schematic cross-sectional view of the power storage module shown.

[0037] Fig.15 yes Fig.13 A schematic cross-sectional view of the mold is shown.

[0038] Fig.16 1 is a schematic top view of another example of a power storage module.

[0039] Fig.17 yes Fig.16 A schematic cross-sectional view of the mold is shown.

[0040] Fig.18 This is a schematic cross-sectional view of another example of a power storage module.

[0041] Fig.19 It is a diagram showing another example of the contact surface of the mold with respect to the electrode stack. DETAILED DESCRIPTION

[0042] Hereinafter, an embodiment will be described with reference to the accompanying drawings. In addition, in the description of the accompanying drawings, the same reference numerals are used to denote the same or equivalent elements, and repeated descriptions are sometimes omitted. In addition, when describing, reference may be made to an orthogonal coordinate system defined by the X-axis, Y-axis, and Z-axis shown in the accompanying drawings.

[0043] Figure 1 1 is a schematic top view of a power storage module according to the present embodiment. The power storage module 1 is a power storage module used in batteries of various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage module 1 is a secondary battery such as a nickel-hydrogen secondary battery or a lithium-ion secondary battery. The power storage module 1 may be a 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 shown.

[0044] The power storage module 1 includes an electrode stack 10 and an injection resin portion 50. The electrode stack 10 is rectangular when viewed from the Z-axis direction (first direction). The electrode stack 10 has four outer side surfaces 20s. The injection resin portion 50 is bonded to one outer side surface 20sA (liquid injection port surface) among the four outer side surfaces 20s. The outer side surface 20sB among the other three outer side surfaces 20sB, 20sC, and 20sD is the surface on the opposite side of the outer side surface 20sA. The outer side surface 20sC and the outer side surface 20sD are surfaces connecting the outer side surface 20sA and the outer side surface 20sB. In the example shown in the figure, when viewed from the Z-axis direction, the outer side surfaces 20sA and 20sB constitute the short sides, and the outer side surfaces 20sC and 20sD constitute the long sides. For example, when viewed from the Z-axis direction, the power storage module can be rectangular in size of about 300mm×700mm to 1300mm×2000mm.

[0045] Figure 2 It is along Figure 1 The cross-sectional view of the II-II line shows the vicinity of the outer side surface 20sD. In addition, the vicinity of the outer side surfaces 20sB and 20sC also becomes Figure 2 Same cross section. Figure 3 This is a diagram when the injected resin portion 50 is viewed from the front, and the outer side surface 20sA is partially shown. Figure 4 It is along Figure 3 The cross section of line IV-IV, Figure 5 It is along Figure 3 The cross section of the VV line, Figure 6 It is along Figure 3 The cross section of line VI-VI.

[0046] The electrode stack 10 includes a plurality of electrodes stacked along the Z-axis direction. The Z-axis direction is the stacking direction of the electrodes and is the height direction of the power storage module 1. The plurality of electrodes include a plurality of bipolar electrodes 11, a positive terminal electrode 12, and a negative terminal electrode 13. A separator 14 is interposed between adjacent electrodes.

[0047] The bipolar electrode 11 has a current collector 15, a positive electrode active material layer 16, and a negative electrode active material layer 17. The current collector 15 is rectangular and sheet-shaped when viewed from the Z-axis direction. The current collector 15 has a first region R1 formed with active material layers (positive electrode active material layer 16, negative electrode active material layer 17) and a frame-shaped second region R2 that is closer to the outside than the first region R1. The first region R1 is arranged in the center of the current collector 15 when viewed from the Z-axis direction. The positive electrode active material layer 16 is arranged on the first surface 15a of the current collector 15. The negative electrode active material layer 17 is arranged on the second surface 15b of the current collector 15. The plurality of bipolar electrodes 11 are stacked in such a manner that the positive electrode active material layer 16 of one bipolar electrode 11 adjacent to the other bipolar electrode 11 in the stacking direction faces the negative electrode active material layer 17 of the other bipolar electrode 11. Here, the first surface 15 a of the current collector 15 is a surface facing one direction in the Z-axis direction, and the second surface 15 b of the current collector 15 is a surface facing the other direction in the Z-axis direction.

[0048] The positive electrode active material layer 16 and the negative electrode active material layer 17 are rectangular when viewed from the Z-axis direction. The negative electrode active material layer 17 is slightly larger than the positive electrode active material layer 16 when viewed from the Z-axis direction. When viewed from above from the Z-axis 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.

[0049] The positive terminal electrode 12 has a current collector 15 and a positive electrode active material layer 16 provided on a first surface 15a of the current collector 15. The positive terminal electrode 12 does not have a positive electrode active material layer 16 and a negative electrode active material layer 17 on a second surface 15b of the current collector 15. That is, no active material layer is provided on the second 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 end portion on the other side of the electrode stack 10 in the Z-axis direction. The positive terminal electrode 12 is stacked on the bipolar electrode 11 in such a manner that its positive electrode active material layer 16 faces the negative electrode active material layer 17 of the bipolar electrode 11.

[0050] The negative terminal electrode 13 has a current collector 15 and a negative electrode active material layer 17 provided on the second surface 15b of the current collector 15. The negative terminal electrode 13 does not have a positive electrode active material layer 16 and a negative electrode active material layer 17 on the first surface 15a of the current collector 15. That is, no active material layer is provided on the first surface 15 of the current collector 15 of the negative terminal electrode 13. The negative terminal electrode 13 is stacked on the bipolar electrode 11 at an end portion on one side in the Z-axis direction of the electrode stack 10. The negative terminal electrode 13 is stacked on the bipolar electrode 11 in such a manner that its negative electrode active material layer 17 faces the positive electrode active material layer 16 of the bipolar electrode 11.

[0051] The separator 14 is disposed between adjacent bipolar electrodes 11, between the positive terminal electrode 12 and the bipolar electrode 11, and between the negative terminal electrode 13 and the bipolar electrode 11. The separator 14 is interposed between the positive electrode active material layer 16 and the negative electrode active material layer 17 to separate the positive electrode active material layer 16 from the negative electrode active material layer 17. The separator 14 prevents short circuits caused by contact between adjacent electrodes and allows charge carriers such as lithium ions to pass through.

[0052] The current collector 15 is a chemically inert electrical conductor used to allow current to continue to flow through the positive electrode active material layer 16 and the negative electrode active material layer 17 during the discharge or charge period 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. As the conductive resin material, for example, a conductive polymer material or a resin formed by adding a conductive filler to a non-conductive polymer material as needed can be listed. The current collector 15 can also have a plurality of layers. In this case, each layer of the current collector 15 can also include the above-mentioned metal material or conductive resin material.

[0053] A coating layer may also be formed on the surface of the current collector 15. The coating layer may be formed by a known method such as plating or spraying. The current collector 15 may be, for example, in the form of a plate, a foil (such as a metal foil), a film, or a mesh. Examples of metal foils include aluminum foil, copper foil, nickel foil, titanium foil, or stainless steel foil. Examples of stainless steel foils include SUS 304, SUS 316, or SUS 301 specified in JIS G 4305:2015. By using stainless steel foil as the current collector 15, the mechanical strength of the current collector 15 can be ensured. The current collector 15 may also be an alloy foil or a clad foil of the above-mentioned 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.

[0054] The positive electrode active material layer 16 contains a positive electrode active material that can absorb and release 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 can be any positive electrode active material that can be used in a lithium ion secondary battery. The positive electrode active material layer 16 may also 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 (LiFePO4) as a composite oxide.

[0055] The negative electrode active material layer 17 contains a negative electrode active material that can absorb and release charge carriers such as lithium ions. The negative electrode active material can be any one of a simple substance, an alloy or a compound. As the negative electrode active material, for example, lithium (Li), carbon, a metal compound, etc. can be listed. The negative electrode active material can also be an element or a compound thereof that can be alloyed with lithium. As carbon, for example, natural graphite, artificial graphite, hard carbon (difficult to graphitize carbon) or soft carbon (easy to graphitize carbon) can be listed. As artificial graphite, for example, highly oriented graphite, mesophase carbon microbeads, etc. can be listed. As elements that can be alloyed with lithium, silicon (silicon) or tin can be listed. In the present embodiment, the negative electrode active material layer 17 contains graphite as a carbon-based material.

[0056] The positive electrode active material layer 16 and the negative electrode active material layer 17 (hereinafter, sometimes referred to as "active material layer") may each contain a conductive aid for improving electrical conductivity, a binder, an electrolyte (polymer matrix, ion conductive polymer, electrolyte solution, etc.), an electrolyte supporting salt (lithium salt) for improving ion conductivity, etc. as needed. The conductive aid is added to improve the conductivity of each electrode (bipolar electrode 11, positive terminal electrode 12, negative terminal electrode 13). The conductive aid is, for example, acetylene black, carbon black, or graphite.

[0057] As the binder, there can be listed fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, fluorine rubber, thermoplastic resins such as polypropylene and polyethylene, imide resins such as polyimide and polyamide-imide, resins containing alkoxysilyl groups, acrylic resins such as acrylic acid or methacrylic acid, styrene-butadiene rubber (SBR), carboxymethyl cellulose, sodium alginate, alginates such as ammonium alginate, water-soluble cellulose ester crosslinked products, starch-acrylic acid graft polymers, etc. These binders can be used alone or in combination. For example, water, N-methyl-2-pyrrolidone (NMP), etc. are used as solvents.

[0058] The separator 14 can be, for example, a porous sheet or nonwoven fabric containing a polymer that absorbs and retains an electrolyte. Examples of the material of the separator 14 include polypropylene, polyethylene, polyolefin, polyester, and the like. The separator 14 can have a single-layer structure or a multi-layer structure. The multi-layer structure can have, for example, an adhesive layer or a ceramic layer as a heat-resistant layer. The separator 14 can also be impregnated with an electrolyte. The separator 14 can also be composed of an electrolyte such as a polymer electrolyte or an inorganic electrolyte. Examples of the electrolyte impregnated into the separator 14 include a liquid electrolyte (electrolyte) containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent, or a polymer gel electrolyte containing an electrolyte retained in a polymer matrix.

[0059] When the separator 14 is impregnated with an electrolyte, known lithium salts such as LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, and LiN(CF3SO2)2 can be used as the electrolyte salt. In addition, known solvents such as cyclic carbonates, cyclic esters, chain carbonates, chain esters, and ethers can be used as the non-aqueous solvent. In addition, two or more of these known solvent materials can also be used in combination.

[0060] The electrode stack 10 also includes a sealing body 20. The sealing body 20 is formed in a frame shape at the peripheral portion of the electrode stack 10 in a manner that forms the outer edge of the electrode stack 10 when viewed from the Z-axis direction. The sealing body 20 can be joined to each of the first surface 15a and the second surface 15b of the current collector 15 at the peripheral portion 15c of each current collector 15. The sealing body 20 forms an internal space S between the current collectors 15 adjacent in the Z-axis direction, and seals each of the internal spaces S. An electrolyte is contained in each internal space S (not shown). That is, the sealing body 20 cooperates with the current collectors 15 adjacent in the Z-axis direction to define the internal space S for containing the electrolyte. The sealing body 20 prevents the electrolyte from penetrating to the outside.

[0061] The sealing body 20 suppresses the intrusion of moisture or the like from the outside of the electrode stack 10 into the internal space S. For example, the sealing body 20 prevents the gas generated at each electrode due to the charge and discharge reaction or the like from leaking to the outside of the power storage module 1. The edge of the separator 14 is bonded to the sealing body 20. The sealing body 20 includes 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, and acrylonitrile styrene resin.

[0062] An example of a closure 20 includes a plurality of seals 21, a pair of end seals 24, and a plurality of spacers 22. The seals 21, the end seals 24, and the spacers 22 may be frame-shaped members formed in a sheet shape. In addition, a welded end 23 is formed in the closure 20. The plurality of seals 21 are respectively arranged in the second region R2 of the collector 15 constituting the plurality of bipolar electrodes 11. The seal 21 is frame-shaped when viewed from the Z-axis direction. The seal 21 is arranged along the peripheral portion 15c of the collector 15. In addition, the peripheral portion 15c is the outer peripheral portion of the second region R2. The seal 21 is arranged in a manner from the first surface 15a of the collector 15 through the end surface to the second surface 15b, and the peripheral portion 15c is covered. The seal 21 may be welded to at least one of the first surface 15a and the second surface 15b of the collector 15.

[0063] The end seal 24 is provided in the second region R2 of the current collector 15 constituting the positive terminal electrode 12 and the negative terminal electrode 13. Therefore, the end seal 24 is arranged in a manner of sandwiching a plurality of seals 21 from the Z-axis direction. The end seal 24 is frame-shaped when viewed from the Z-axis direction. The end seal 24 is provided along the peripheral edge 15c of the current collector 15 in the same manner as the seal 21. For example, when viewed from the Z-direction, the width of the seal 21 in the region along the outer side surface 20sA is wider than the width of the seal 21 in the region along the outer side surfaces 20sB, 20sC, and 20sD. In addition, when viewed from the Z-axis direction, the width of the end seal 24 is wider than the seal 21. That is, the inner edge of the end seal 24 is located at a position closer to the inside than the inner edge of the seal 21. In addition, the width of the seal 21 in the region along the outer side surfaces 20sA and 20sB may also be the distance of the seal 21 in the region in the Y-axis direction (second direction). In addition, the width of the seal 21 in the region along the outer side surfaces 20sC and 20sD may be the distance of the seal 21 in the region in the X-axis direction (third direction).

[0064] The spacer 22 is frame-shaped when viewed from the Z-axis direction. The spacer 22 is arranged along the peripheral portion 15c of the collector 15. The spacer 22 is arranged in a manner interposed between the seals 21 adjacent in the Z-axis direction. The spacer 22 can be fused to at least one of a pair of seals 21 adjacent in the Z-axis direction. In addition, the spacer 22 is arranged in a manner interposed between the seals 21 and the end seals 24 adjacent in the Z-axis direction. The spacer 22 can be fused to at least one of the seals 21 and the end seals 24 adjacent in the Z-axis direction. The spacer 22 can maintain the space between the collectors 15 adjacent in the Z-axis direction. That is, the spacer 22, the seal 21 and the end seal 24 define the internal space S between the adjacent collectors 15.

[0065] When viewed from the Z-axis direction, the width of the spacer 22 in the region along the outer side surface 20sA is wider than the width of the spacer 22 in the region along the outer side surfaces 20sB, 20sC, and 20sD. In addition, in the region along the outer side surfaces 20sB, 20sC, and 20sD, the width of the spacer 22 is narrower than the width of the seal 21. That is, in the region along the outer side surfaces 20sB, 20sC, and 20sD, the inner edge of the spacer 22 is located at a position further outward than the inner edge of the seal 21. On the other hand, in the region along the outer side surface 20sA, the width of the spacer 22 is wider than the seal 21. That is, in the region along the outer side surface 20sA, the inner edge of the spacer 22 is located at a position further inward than the inner edge of the seal 21. In addition, the inner edge of the spacer 22 is located at a position further outward than the inner edge of the end seal 24 in any region.

[0066] The welded end 23 is formed by welding the ends of the plurality of seals 21, a pair of end seals 24, and a plurality of spacers 22 on the side opposite to the internal space S to each other and integrating them. The welded end 23 surrounds the collector 15 when viewed from the Z-axis direction, and is frame-shaped in a manner to form the periphery of the electrode stack 10. The side surface of the welded end 23 on the side opposite to the internal space S extends along the Z-axis direction, constituting the outer side surface 20s of the closed body 20. In other words, the closed body 20 includes the outer side surface 20s on the side opposite to the internal space S. The outer side surface 20s can be formed as a flat surface.

[0067] The sealing body 20 has a plurality of communicating holes 27 (see Figure 5 As an example, the communicating hole 27 is formed in a cutout portion of the spacer 22. The communicating hole 27 is formed by penetrating the welded end portion 23. The communicating hole 27 has one opening in the internal space S and another opening in the outer side surface 20s of the closing body 20. In the example shown in the figure, the opening is formed in the outer side surface 20sA.

[0068] The injection resin part 50 is a reinforcing member for reinforcing the outer side surface 20sA formed with the communicating hole 27. The injection resin part 50 is formed into a predetermined shape to provide a liquid injection port communicating with the communicating hole 27. The injection resin part 50 is joined to the closing body 20. For example, the injection resin part 50 is integrally joined to the closing body 20 by injection molding. An example of the injection resin part 50 includes a main body 51, a first overhang part 55, a second overhang part 57, and a first thin-walled part 59.

[0069] The main body 51 partially covers the outer side surface 20sA. For example, the main body 51 covers the outer side surface 20sA in a manner including a region (main body region) R3 where a plurality of connecting holes 27 are formed on the outer side surface 20sA. As described above, the plurality of connecting holes 27 are connected to the plurality of internal spaces S, respectively. Figure 3 In the example shown, 30 communication holes 27 corresponding to the 30 layers of internal spaces formed between the current collectors 15 are discretely arranged in the X-axis direction and the Z-axis direction. More specifically, with the positive terminal electrode 12 side as the base end, the communication holes 27 corresponding to the internal spaces of the first to tenth layers are evenly spaced and arranged along the X-axis direction, and the communication holes 27 corresponding to the internal spaces of the eleventh to twentieth layers and the communication holes 27 corresponding to the internal spaces of the twenty-first to thirtieth layers are arranged in sequence in the Z-axis direction below the internal spaces of the first to tenth layers. The main body 51 extends in a rectangular shape along the X-axis direction and the Z-axis direction in order to cover the main body region R3 where these 30 communication holes 27 are formed.

[0070] The main body 51 is formed into a rectangular plate having a predetermined thickness in the Y-axis direction. For example, the thickness L2 of the main body 51 in the Y-axis direction may be 2.0±0.5 mm. The main body 51 has an opening 52 at a position corresponding to the connecting hole 27. The thickness L2 of the main body 51 is equivalent to the depth of the opening 52 provided in the main body 51 in the Y-axis direction. In addition, the main body 51 has a frame-shaped protruding frame portion 53 protruding outward along the Y-axis direction. When viewed from the Y-axis direction, the protruding frame portion 53 separates each opening 52 (see Figure 3 ) surrounds the openings 52 and functions as a partition wall separating the openings 52. In the example shown in the figure, 10 protruding frame portions 53 are arranged in the X-axis direction to form three spaces for separating three openings 52 arranged vertically. For example, the thickness of the protruding frame portion 53 in the Y-axis direction can be about 0.5 mm to 6.0 mm.

[0071] As an example, the protruding frame 53 is used when injecting the electrolyte into each of the internal spaces S. For example, when injecting the electrolyte, the nozzle of the injection device is brought into close contact with the top surface of the protruding frame 53, and the electrolyte is introduced from the nozzle into the space of each protruding frame 53. In this way, the electrolyte can be injected into the internal space S from the opening 52 and the connecting hole 27.

[0072] After the electrolyte solution is injected, a laminate sheet 54 for sealing the protruding frame 53 may be provided on the protruding frame 53 (see Figure 5 The laminate sheet 54 may be, for example, a sheet formed by coating a metal layer such as aluminum with a resin layer. The laminate sheet 54 may be fused to the top surface of the protruding frame portion 53, for example.

[0073] like Figure 4 As shown, the two end faces of the electrode stack 10 in the Z-axis direction are composed of a first end face 10a and a second end face 10b. The first end face 10a is the outermost surface on the positive side of the electrode stack 10 in the Z-axis direction. That is, the first end face 10a includes the exposed surface of the second face 15b of the positive terminal electrode 12 and the exposed surface of the end seal 24 joined to the periphery of the positive terminal electrode 12. The second end face 10b is the outermost surface on the negative side of the electrode stack 10 in the Z-axis direction. That is, the second end face 10b includes the exposed surface of the first face 15a of the negative terminal electrode 13 and the exposed surface of the end seal 24 joined to the periphery of the negative terminal electrode 13. The first overhanging portion 55 is formed by connecting to the first end edge 51a of the main body 51 in the Z-axis direction. The first overhanging portion 55 partially covers the first end face 10a of the electrode stack 10. For example, the first overhanging portion 55 partially covers the end seal 24 joined to the positive terminal electrode 12 constituting the first end surface 10a. In the example shown in the figure, when viewed from the Z-axis direction, the end edge 55a of the first overhanging portion 55 extends to a position that is inside the outer edge 14a of the separator 14 and outside the inner edge 22a of the spacer 22. The first overhanging portion 55 can be formed into a rectangular plate having the same length as the main body 51 in the X-axis direction. For example, the thickness of the first overhanging portion 55 in the Z-axis direction can be 1.5±0.5 mm, or it can be thinner.

[0074] The second overhanging portion 57 is connected to the second end edge 51b of the main body 51 on the opposite side to the first end edge 51a, and partially covers the second end face 10b of the electrode stack 10. For example, the second overhanging portion 57 partially covers the end seal 24 joined to the negative terminal electrode 13 constituting the second end face 10b. In the example shown in the figure, when viewed from the Z-axis direction, the end edge 57a of the second overhanging portion 57 extends to a position that is inside the outer edge 14a of the separator 14 and outside the inner edge 22a of the spacer 22. The second overhanging portion 57 can be formed into a rectangular plate having the same length as the main body 51 in the X-axis direction. For example, the thickness of the second overhanging portion 57 in the Z-axis direction can be 1.5±0.5 mm, or it can be different from the thickness of the first overhanging portion 55.

[0075] The first thin-walled portion 59 is formed by connecting to both end edges of the main body portion 51 in the X-axis direction, that is, the third end edge 51c and the fourth end edge 51d (see Figure 3 ). The first thin-walled portion 59 extends from the main body 51 along the outer side surface 20sA and is joined to the outer side surface 20sA. The size of the first thin-walled portion 59 in the Z-axis direction may be the same as the size of the main body 51 in the Z-axis direction. The thickness L1 of the first thin-walled portion 59 in the Y-axis direction (see Figure 6 ) is smaller than the thickness L2 of the main body 51 in the Y-axis direction (refer to Figure 4). The thickness L1 of the first thin-walled portion 59 may be less than 1 / 3 of the thickness L2 of the main body portion 51. For example, the thickness of the first thin-walled portion 59 in the Y-axis direction may be less than 0.5 mm. Figure 3 In the example, the first thin-walled portion 59 is rectangular when viewed from the Y-axis direction, but the first thin-walled portion 59 only needs to have an area joined to the outer side surface 20sA, and the shape of the first thin-walled portion 59 is not limited to a rectangle.

[0076] A conductive member that functions as a terminal for extracting current from the power storage module 1 may be arranged and electrically connected to the first surface 15a of the collector 15 of the positive terminal electrode 12 and the second surface 15b of the collector 15 of the negative terminal electrode 13 that are exposed from the sealing body 20. The conductive member may be used to electrically connect a plurality of power storage modules 1. In addition, the conductive member may be used as a restraining member to add a restraining load to the electrode stack 10. Moreover, a cooling flow path may be formed in the conductive member. By allowing a cooling medium to flow through the cooling flow path formed in the conductive member, the electrode stack 10 can be cooled.

[0077] Next, a method for manufacturing the power storage module will be described. Figure 7 1 is a flowchart showing an example of a method for manufacturing a storage battery module. In one example of the manufacturing method, first, an electrode stack 10 including a plurality of electrodes stacked along the Z-axis direction is formed (step S1). Thus, the electrode stack 10 is prepared. In addition, in the stage of step S1, the closed body 20 of the formed electrode stack 10 does not have a welded end 23. That is, the end seal 24, the seal 21, and the spacer 22 stacked along the Z-axis direction are not welded to each other.

[0078] In addition, the spacer 22 may have a cutout portion connected from the internal space S to the outer edge at a position corresponding to the connecting hole 27. In step S1, the electrode stack 10 is formed in a state where a nested piece is arranged in the cutout portion formed in the spacer 22. The electrode stack 10 formed in this way has a plurality of nested pieces protruding from the side surface corresponding to the outer side surface 20sA. The nested piece is inserted into the cutout portion to prevent the cutout portion from being blocked in the subsequent process. By removing the nested piece after injection molding, the connecting hole 27 and the opening 52 are formed in the portion where the nested piece is arranged. The nested piece may be, for example, a metal plate.

[0079] Next, the welded end 23 is formed on the electrode stack 10 (step S2). Thereby, an internal space S is formed between adjacent current collectors 15. In the process of forming the welded end 23, the outer edge portions of the seal 21, the end seal 24, and the spacer 22 constituting the electrode stack 10 on the side opposite to the internal space S are welded to each other. In addition, the welded end 23 is formed in an original state in which a nested member is arranged in the cut-out portion of the spacer 22. In one example, the thickness of the welded end 23 corresponding to the other outer side surfaces 20sB, 20sC, and 20sD may be thicker than the thickness of the welded end 23 corresponding to the outer side surface 20sA.

[0080] Next, the injection resin portion 50 is formed on the sealing body 20 of the electrode stack 10 (step S3). The process of forming the injection resin portion 50 includes: attaching a mold that partially covers the outer surface 20sA to the electrode stack 10; and injecting resin into the molding space of the mold. Figure 8 FIG. 2 is a plan view showing the position of the mold 70 assembled to an example of a power storage module. Figure 8 In FIG. 1 , the assembly position of the mold 70 is shown by a dotted line. Fig. 9 It is schematically shown Figure 8 A cross-sectional view of the mold at the position of line IX-IX. Fig.10 It is schematically shown Figure 8 Cross-sectional view of the mold at the position of line XX. Fig.11 It is schematically shown Figure 8 A cross-sectional view of the mold at the position of the XI-XI line.

[0081] In step S3, a mold 70 is installed on the electrode stack 10 placed on the mounting table to form a continuous molding space C (see FIG. 1 ) between the main body region R3, the first overhang region R4, and the second overhang region R5 of the electrode stack 10. Fig. 9 The thickness of the molding space C in the Y-axis direction is equal to the thickness L2 of the main body 51 (see Figure 4 ). In addition, the thickness of the forming space C in the Z-axis direction can also be controlled to be constant. As a result, the storage module 1 can be manufactured with good precision and stability. In the case where there is a tolerance in the size of the electrode stack 10, the volume of the forming space C can be changed, for example, according to the thickness of the electrode stack 10 in the Z-axis direction arranged in the mold 70. In this case, the thickness of the first overhang portion 55 and the thickness of the second overhang portion 57 can also be different.

[0082] The main body region R3 is a region of the outer side surface 20sA that includes a plurality of connecting holes 27. The main body region R3 is a bonding surface with the main body portion 51. The first overhang region R4 is connected to the first end edge R3a of the main body region R3 in the Z-axis direction. The first overhang region R4 is a region that partially extends from the first end face 10a of the electrode stack 10 that intersects the Z-axis direction. The first overhang region R4 is a bonding surface with the first overhang portion 55. The second overhang region R5 is connected to the second end edge R3b of the main body region R3 that is opposite to the first end edge R3a. The second overhang region R5 is a region that partially extends from the second end face 10b of the electrode stack 10 that is opposite to the first end face 10a. The second overhang region R5 is a bonding surface with the second overhang portion 57.

[0083] In addition, by installing the mold 70 on the electrode stack 10, a first thin-walled space SS1 extending from the molding space C along the outer side surface 20sA is formed (see Fig.10 The thickness of the first thin-walled space SS1 in the Y-axis direction is equal to the thickness L1 of the first thin-walled portion 59 (see Figure 4 ) corresponds. In addition, since the first thin-walled space SS1 is a space formed in the mold 70 together with the forming space C, it can be understood as a part of the forming space C, but in this specification, the first thin-walled space SS1 is defined as another space connected to the forming space C.

[0084] The mold 70 may include a first mold 71 and a second mold 74 that clamp the electrode stack 10 from the Z-axis direction. In addition, the mold 70 may include a third mold 77 disposed between the first mold 71 and the second mold 74. Fig. 9 As shown, the first mold 71 has: abutting surface 72, which abuts against the first end surface 10a of the electrode stack 10; and an inner surface 71a, which faces the first overhang region R4. Similarly, the second mold 74 has: abutting surface 75, which abuts against the second end surface 10b of the electrode stack 10; and an inner surface 74a, which faces the second overhang region R5.

[0085] The electrode stack 10 is clamped by the abutting surface 72 of the first mold 71 and the abutting surface 75 of the second mold 74 in a manner such that the outer edge of the electrode stack 10 is exposed in the forming space C within the range of the main body 51 formed in the X-axis direction. In one example, the abutting surface 72 of the first mold 71 can abut against the end seal 24 at the position where the spacer 22, the seal 21, and the separator 14 overlap when viewed from the Z-axis direction. Similarly, the abutting surface 75 of the second mold 74 can also abut against the end seal 24 at the position where the spacer 22, the seal 21, and the separator 14 overlap. In addition, the collector 15 can also extend at the position where the spacer 22, the seal 21, and the separator 14 overlap.

[0086] The third mold 77 is arranged between the first mold 71 and the second mold 74 in the Z-axis direction, and forms a molding space C together with the first mold 71 and the second mold 74. The third mold 77 includes: a contact surface 77b that contacts the first mold 71; a contact surface 77c that contacts the second mold 74; and an inner surface 77a that faces the main body region R3. Within the range of forming the main body 51 in the X-axis direction, the inner surface 77a of the third mold 77 is separated from the main body region R3 in the outer side surface 20sA by a thickness L2 (refer to Figure 4 ) at a considerable distance.

[0087] In addition, in step S3 of one example, first, the second mold 74 is configured to contact the electrode stack 10. In this case, the electrode stack 10 may also be placed on the stage in such a manner that the end portion including the outer side surface 20sA extends from the stage. Next, the first mold 71 presses the electrode stack 10 from the Z-axis direction, so that the electrode stack 10 is clamped by the first mold 71 and the second mold 74. Thereafter, the third mold 77 is configured. In addition, the mold 70 only needs to partially cover the outer side surface 20sA of the electrode stack 10. In one example, the two end edges of the outer side surface 20sA in the X-axis direction may be exposed to the outside of the mold 70.

[0088] like Fig.10 As shown, in the X-axis direction, within the range outside the area where the main body 51 is formed and the first thin-walled portion 59 is formed, the abutment surface 72 of the first mold 71 and the abutment surface 75 of the second mold 74 extend to the position of the outer side surface 20sA which is the outer periphery of the electrode stack 10. In addition, the third mold 77 has an inner surface 77d which is closer to the outer side surface 20sA of the electrode stack 10 than the inner surface 77a. The inner surface 77d faces the first thin-walled region R6 which is joined to the first thin-walled portion 59 in the outer side surface 20sA. The distance from the inner surface 77d to the outer side surface 20sA is equal to the thickness L1 of the first thin-walled portion 59 (see Figure 6 ) corresponding to.

[0089] like Fig.11 As shown, at the end in the X-axis direction, the contact surfaces of the first mold 71 and the second mold 74 extend to the position of the outer side surface 20sA of the electrode stack 10, similarly to the range of forming the first thin-walled portion 59. In addition, the third mold 77 has a contact surface 77e that contacts the outer side surface 20sA. When the electrode stack 10 is assembled with the mold 70, the contact surface 77e of the third mold 77 may also be pressed against the outer side surface 20sA of the electrode stack 10.

[0090] Fig.12Schematically shows the contact surface of the mold with respect to the electrode stack. The contact surface 72 of the first mold 71 and the contact surface 75 of the second mold 74 have the same shape. Fig.12 In FIG. 7 , the abutment surface 72 of the first mold 71 is representatively shown. Fig.12 As shown, a groove is formed on the abutting surface 72 of the first mold 71. The groove of the illustrated example forms a mesh pattern when viewed from the Z-axis direction. That is, the groove is formed by the intersection of a plurality of first straight lines 72a inclined at a first angle and a plurality of second straight lines 72b inclined at a second angle when viewed from the Z-axis direction. The first straight line 72a and the second straight line 72b intersect in both the X-axis direction and the Y-axis direction. By having the above-mentioned shape, the surface roughness of the abutting surface of the first mold 71 and the second mold 74 is greater than the surface roughness of the forming surface (i.e., the inner surface) of the forming space C of the mold 70. In addition, both ends of the abutting surface 72 in the Y-axis direction may also be rounded (R-processed).

[0091] After the electrode stack 10 is assembled with the mold 70 in step S3, a resin is injected into the molding space C of the mold 70, so that the injection resin portion 50 is formed (step S4). In step S4, the molding space C is filled with resin, and the resin leaking from the molding space C can be filled into the first thin-walled space SS1. In step S4, it is not necessary to completely fill the first thin-walled space SS1 with resin, as long as a portion of the resin enters. That is, the first thin-walled portion 59 formed by step S4 does not need to be rectangular corresponding to the first thin-walled space SS1 when viewed from the Y-axis direction, and there may be a gap at the end or the periphery.

[0092] In addition, Figures 9 to 11 , the mold 70 is schematically shown, but a depression corresponding to the protruding frame portion 53 may be formed in the mold 70. In addition, for example, a holding portion for holding the nested piece protruding from the electrode stack 10 may be formed in the mold 70. After the injection resin portion 50 is formed in step S4, the nested piece is pulled out, so that the opening 52 connected to the communication hole 27 is formed in the injection resin portion 50 bonded to the electrode stack 10.

[0093] Fig.13 FIG. 1 is a schematic top view of another example of a power storage module. Fig.14 yes Fig.13 A schematic cross-sectional view of the power storage module shown. Fig.15 yes Fig.13 A schematic cross-sectional view of the mold is shown. Figure 13 to Figure 15In the example shown, the power storage module has an injection resin portion 150 having a shape different from that of the injection resin portion 50. The injection resin portion 150 includes a main body portion 51, a first overhang portion 55, a second overhang portion 57, a first thin-walled portion 59, and a second thin-walled portion 159. The main body portion 51, the first overhang portion 55, the second overhang portion 57, and the first thin-walled portion 59 have the same configuration as that of the injection resin portion 50, and thus description thereof will be omitted.

[0094] The second thin-walled portion 159 is formed by connecting to both end edges of the first overhang portion 55 and the second overhang portion 57 in the X-axis direction. In addition, the second thin-walled portion 159 may also be connected to the first thin-walled portion 59. The second thin-walled portion 159 extends from the first overhang portion 55 and the second overhang portion 57 along the end seal 24. The thickness L3 of the second thin-walled portion 159 in the Z-axis direction is smaller than the thickness L4 and L5 of the first overhang portion 55 and the second overhang portion 57 in the Z-axis direction. For example, the thickness L3 may be less than 1 / 3 of the thickness L4 or the thickness L5. In addition, the second thin-walled portion 159 and the first thin-walled portion 59 may have the same thickness, and the relationship between the thickness L3 of the second thin-walled portion 159 and the thickness L4 and L5 of the first overhang portion 55 and the second overhang portion 57 may be the same as the relationship between the thickness L1 of the first thin-walled portion 59 and the thickness L2 of the main body 51. In the example shown in the figure, the second thin-walled portion 159 has a rectangular shape when viewed from the Z-axis direction, but the shape of the second thin-walled portion 159 is not limited to the rectangular shape.

[0095] As shown in the cross-sectional view of the mold 170 at a position corresponding to the second thin-walled portion 159 Fig.15 As shown, the first thin-wall space SS1 and the second thin-wall space SS2 for forming the first thin-wall portion 59 and the second thin-wall portion 159 are formed by the first mold 171, the second mold 174, and the third mold 177 constituting the mold 170. That is, the first mold 171 has, within the range in the X-axis direction where the second thin-wall portion 159 is formed, a contact surface 172 that contacts the first end surface 10a (end seal 24) of the electrode stack 10, and an inner surface 171a that faces the second thin-wall region R7, which is a region in the first end surface 10a where the second thin-wall portion 159 is joined.

[0096] Similarly, the second mold 174 has, within the range in which the second thin-walled portion 159 is formed in the X-axis direction, a contact surface 175 that contacts the second end surface 10b (end seal 24) of the electrode stack 10, and an inner surface 174a that faces the second thin-walled region R7, which is a region in the second end surface 10b where the second thin-walled portion 159 is joined. The inner surface 171a of the first mold 171 and the inner surface 174a of the second mold 174 are separated from the electrode stack 10 by a distance corresponding to the second thin-walled portion 159. In addition, the third mold 177 includes: a contact surface 177a that contacts the first mold 171; a contact surface 177b that contacts the second mold 174; and an inner surface 177c that faces the outer side surface 20sA. Within the range in which the second thin-walled portion 159 is formed in the X-axis direction, the inner surface 177c of the third mold 177 is separated from the outer side surface 20sA by a distance corresponding to the first thin-walled portion 59.

[0097] When the mold 170 is attached to the electrode stack 10 , the resin injected into the mold 170 fills the molding space C of the mold 170 and flows into the first thin-walled space SS1 and the second thin-walled space SS2 . Thus, the first thin-walled portion 59 and the second thin-walled portion 159 are formed.

[0098] Fig.16 1 is a schematic top view of another example of a power storage module. Fig.17 yes Fig.16 A schematic cross-sectional view of the mold is shown. Fig.16 and Fig.17 In the example of , the power storage module has an injection resin portion 250 having a shape different from that of the injection resin portion 150. The injection resin portion 250 includes a main body portion 51, a first overhang portion 55, a second overhang portion 57, a first thin-walled portion 59, a second thin-walled portion 159, and a third thin-walled portion 259. The main body portion 51, the first overhang portion 55, the second overhang portion 57, the first thin-walled portion 59, and the second thin-walled portion 159 have the same structure as that of the injection resin portion 150, and thus description thereof is omitted.

[0099] The third thin-walled portion 259 is formed by connecting to the end edges of the first overhang portion 55 and the second overhang portion 57 in the Y-axis direction. In addition, the third thin-walled portion 259 may also be connected to the second thin-walled portion 159. The third thin-walled portion 259 extends from the first overhang portion 55 and the second overhang portion 57 along the end seal 24. The thickness of the third thin-walled portion 259 in the Z-axis direction is smaller than the thickness of the first overhang portion 55 and the second overhang portion 57 in the Z-axis direction, and may be the same as the thickness of the second thin-walled portion 159, for example. In addition, in the example shown in the figure, the third thin-walled portion 259 is rectangular when viewed from the Z-axis direction, but the shape of the third thin-walled portion 259 is not limited to a rectangular shape.

[0100] As shown in the cross-sectional view of the mold 270 at a position corresponding to the third thin-walled portion 259 Fig.17 As shown, the first mold 271 has, within the range of forming the third thin-walled portion 259 in the X-axis direction: abutting surface 272, which abuts against the first end face 10a (end seal 24) of the electrode stack 10; an inner surface 271a, which faces the area where the third thin-walled portion 259 is joined in the first end face 10a, namely, the third thin-walled area R8; and an inner surface 271b, which faces the first overhang area R4.

[0101] Similarly, the second mold 274 has, within the range of forming the third thin-walled portion 259 in the X-axis direction, a contact surface 275 that contacts the second end surface 10b (end seal 24) of the electrode stack 10, an inner surface 274a that faces the third thin-walled region R8, which is a region where the third thin-walled portion 259 is joined in the first end surface 10a, and an inner surface 274b that faces the second overhang region R5. The inner surface 271a of the first mold 271 and the inner surface 274a of the second mold 274 are separated from the electrode stack 10 (end seal 24) by a distance corresponding to the third thin-walled portion 259. In addition, the third mold 277 includes a contact surface 277b that contacts the first mold 271, a contact surface 277c that contacts the second mold 274, and an inner surface 277a that faces the main region R3.

[0102] When the mold 270 is mounted on the electrode stack 10, the resin injected into the mold 270 fills the molding space C of the mold 270 and flows into the first thin-walled space SS1, the second thin-walled space SS2, and the third thin-walled space SS3. Thus, the first thin-walled portion 59, the second thin-walled portion 159, and the third thin-walled portion 259 are formed.

[0103] Fig.18 FIG. 1 is a schematic cross-sectional view of another example of a power storage module. Fig.18 In the example, the storage module and Figure 5 The example of the embodiment of the present invention also has the injection resin part 50, but the storage battery module may also have the injection resin part 150 or the injection resin part 250. In this storage battery module, the laminate sheet 25 may be joined to the end seal 24 constituting the first end face 10a and the second end face 10b of the electrode stack 10. For example, the laminate sheet 25 may be welded to the end seal 24. The laminate sheet 25 may be a sheet formed by covering a metal layer such as aluminum with a resin layer, similarly to the laminate sheet 54.

[0104] For example, the end seal 24 may be covered by the laminate sheet 25. In the illustrated example, the surface of the end seal 24 along the first end face 10a joined to the positive terminal electrode 12 and the surface of the end seal 24 along the second end face 10b joined to the negative terminal electrode 13 are covered by the laminate sheet 25. When viewed from the Z-axis direction, the shape of the laminate sheet 25 is consistent with the shape of the end seal 24. The laminate sheet 25 may be joined to the end seal 24 at any stage before the above-mentioned step S3. By joining the laminate sheet 25 to the outer surface of the end seal 24, the rigidity of the electrode stack 10 is improved. As a result, for example, in step S3, the mold can be more stably assembled to the electrode stack 10.

[0105] Fig.19 FIG. 2 is a diagram showing another example of the contact surface of the mold with respect to the electrode stack. Fig.19 The contact surface 372 of the mold shown is formed with grooves. The contact surface 372 of the example shown is formed with a plurality of grooves 372a extending in the X-axis direction when viewed from the Z-axis direction. The grooves 372a are spaced at equal intervals in the Y-axis direction. By having the above-mentioned shape, the surface roughness of the contact surface 372 of the mold is greater than the surface roughness of the inner surface of the molding space C of the mold.

[0106] As described above, an example of a power storage module 1 includes: an electrode stack 10 including a plurality of electrodes (bipolar electrodes 11, positive terminal electrodes 12, negative terminal electrodes 13) stacked in a first direction, and a sealing body 20 provided in a manner of forming an internal space S between adjacent electrodes and sealing the internal space S; and an injection resin portion 50 joined to the sealing body 20. Each of the plurality of electrodes includes a current collector 15 having a rectangular shape when viewed from the Z-axis direction. The sealing body 20 includes a welded end portion 23 formed by welding the outer peripheral edges of a plurality of frame-shaped members (seals 21, spacers 22) stacked in the Z-axis direction between the plurality of current collectors 15 to each other. The sealing body 20 has: a first end face 10a and a second end face 10b, which are two end faces of the electrode stack 10 in the Z-axis direction; an outer side face 20sA, which is one of the four outer side faces 20s constituting the peripheral surface of the weld end portion 23 (a surface defining the outer edge when viewed from the Z-axis direction) and is joined to the injection resin portion 50; and a plurality of communication holes 27, which connect the outer side of the outer side face 20sA with each of the plurality of internal spaces S. The injection resin portion 50 includes: a main body portion 51, which has a plurality of openings 52 connected to the plurality of communication holes 27, and partially covers the outer side face 20sA; a first hanging portion 55, which is connected to the main body portion 51 and partially covers the first end face 10a; and a second hanging portion 57, which is connected to the main body portion 51 and partially covers the second end face 10b. The main body portion 51 includes a plurality of protruding frame portions 53 protruding in the Y-axis direction intersecting the outer side face 20sA. When viewed from the Y-axis direction, the plurality of protruding frame portions 53 surround the openings 52 connected to the plurality of communication holes 27 .

[0107] In the above-mentioned power storage module 1, a connecting hole 27 penetrating to the internal space S is provided at the welding end 23 of the sealing body 20 formed on the outer periphery of the electrode stack 10. An injection resin part 50 having a protruding frame part 53 surrounding the connecting hole 27 is joined to the sealing body 20. The injection resin part 50 includes: a main body 51 that covers the outer side surface 20sA where the welding end 23 is formed; a first hanging part 55 that extends from the main body 51 to the first end surface 10a of the electrode stack 10; and a second hanging part 57 that extends from the main body 51 to the second end surface 10b of the electrode stack 10. In this way, since the injection resin part 50 is provided only on one of the four outer side surfaces, the size of the power storage module 1 can be suppressed from being enlarged. Such an injection resin part 50 does not require a mold of a size that surrounds the entire periphery of the electrode stack 10, and can be formed by a mold of a size that can partially cover one outer side surface 20sA of the electrode stack 10. In addition, by providing the first overhanging portion 55 and the second overhanging portion 57, the injection resin portion 50 can be firmly joined to the enclosure 20, and the water permeation and gas permeation between the internal space S and the outside along the Z-axis direction can be suppressed.

[0108] The outer side surface 20s of the electrode stack 10 is formed by welding the seal 21, the end seal 24 and the spacer 22. Therefore, the outer side surface 20s is not necessarily a flat surface, and may be composed of an end surface with unevenness. In the case where the outer side surface 20s has unevenness, it is expected that the bonding between the outer side surface 20s and the injection resin part 50 will be reduced.

[0109] Alternatively, the injection resin portion 50 in one example may include a first thin-walled portion 59 connected to the main body portion 51 and joined to the outer side surface 20sA from the main body portion 51, and the thickness of the first thin-walled portion 59 in the Y-axis direction is smaller than the thickness of the main body portion 51 in the Y-axis direction. In this configuration, the injection resin portion 50 can be more firmly joined to the sealing body 20 formed on the outer periphery of the electrode stack 10.

[0110] Alternatively, an example of the injection resin portion 150 may include a second thin-walled portion 159 connected to the first overhang portion 55 and joined to the first end surface 10a from the first overhang portion 55, and the thickness of the second thin-walled portion 159 in the Z-axis direction may be smaller than the thickness of the first overhang portion 55 in the Z-axis direction. Alternatively, an example of the injection resin portion 250 may include a third thin-walled portion 259 connected to the first overhang portion 55 and joined to the first end surface 10a from the first overhang portion 55 along the first end surface 10a, and the thickness of the third thin-walled portion 259 in the Z-axis direction may be smaller than the thickness of the first overhang portion 55 in the Z-axis direction. In this configuration, the injection resin portions 150 and 250 can be more firmly joined to the sealing body 20 formed on the outer periphery of the electrode stack 10. In addition, the thicknesses of the second thin-walled portion 159 and the third thin-walled portion 259 may be the same as or different from each other.

[0111] An example of a current collector 15 includes: a first region R1, which is arranged at the center of the current collector 15 when viewed from the Z-axis direction and has an active material layer formed therein; and a second region R2, which is frame-shaped and is located outside the first region R1. The electrode stack 10 may include: a plurality of seals 21, which are frame-shaped and are arranged in the second region R2 of each of the plurality of current collectors 15; and a plurality of spacers 22, which are interposed between the seals 21 adjacent to each other in the Z-axis direction and define the internal space S between the current collectors 15 together with the plurality of seals 21. In this configuration, the outer peripheral edge of the seal 21 and the outer peripheral edge of the spacer 22 are welded to each other, thereby forming a welded end 23.

[0112] In addition, a manufacturing method of an example of a storage battery module 1 includes: a step of preparing an electrode stack 10 (step S1), the electrode stack 10 including a plurality of electrodes stacked along the Z-axis direction, with two end faces in the Z-axis direction being a first end face 10a and a second end face 10b; a step of providing a welded end portion 23 in the electrode stack 10 so as to form an internal space S between adjacent electrodes (step S2); and a step of forming an injection resin portion 50 in the welded end portion 23 (step S3). The step of providing the welded end portion 23 includes a step of welding the outer peripheral edges of the plurality of seals 21, the plurality of spacers 22, and the end seal 24 to each other. The process of forming the injection resin part 50 includes: a process of assembling the mold 70 to the electrode stack 10 in such a manner that a continuous molding space C is formed between a main body region R3 including a plurality of connecting holes 27 in the outer surface 20sA, a first overhang region R4 connected to the main body region R3 and partially extending on the first end face 10b, and a second overhang region R5 connected to the main body region R3 and partially extending on the second end face 10b; and a process of molding the injection resin part 50 by injecting resin into the molding space C assembled on the electrode stack 10.

[0113] In the manufacturing method of the above-mentioned storage battery module 1, a mold of a size that surrounds the entire periphery of the electrode stack 10 is not required, and the injection resin portion 50 can be formed by a mold 70 of a size that can partially cover one outer side surface 20sA of the electrode stack 10. Therefore, it is possible to suppress the size of the mold required for manufacturing from being enlarged. In addition, it is possible to suppress the size of the manufactured storage battery module from being enlarged. In addition, when the shape of the injection resin portion 50 is the same, even an electrode stack having a larger electrode can use a common mold.

[0114] In one example, in the process of assembling the mold 70, a first thin-walled space SS1 connected to the molding space C and extending from the molding space C along the outer side surface 20sA may be formed, and the thickness of the first thin-walled space SS1 in the Y-axis direction is smaller than the thickness of the molding space C in the Y-axis direction. In this configuration, during injection molding, after the molding space C is filled with resin, the resin can leak from the molding space C to the first thin-walled space SS1. Therefore, the molding space C can be fully filled with resin, and the pressure rise in the molding space C can be alleviated.

[0115] In one example, in the process of assembling the mold, a second thin-walled space SS2 connected to the molding space C and extending from the first overhang region R4 along the first end surface 10a may be formed, and the thickness of the second thin-walled space SS2 in the Z-axis direction is smaller than the thickness of the molding space C in the first overhang region R4 in the Z-axis direction. In this configuration, during injection molding, after the molding space C is filled with resin, the resin can leak from the molding space C to the second thin-walled space SS2. Therefore, the molding space C can be fully filled with resin, and the pressure rise in the molding space C can be alleviated.

[0116] In one example, in the step of assembling the mold, the region of the electrode stack 10 where multiple current collectors 15, multiple seals 21, multiple spacers 22, and multiple separators 14 are repeated when viewed from the Z-axis direction may be clamped by the mold 70. In this configuration, since the region of the electrode stack 10 with a uniform thickness is clamped by the mold 70, the electrode stack 10 can be stably clamped by the mold 70.

[0117] Alternatively, the mold 70 of one example includes a first mold 71 and a second mold 74 that clamp the electrode stack 10 from the Z-axis direction, and the surface roughness of the abutting surface 72 of the first mold 71 that abuts against the electrode stack 10 and the abutting surface 75 of the second mold 74 that abuts against the electrode stack 10 are greater than the surface roughness of the forming surface of the molding space C of the mold 70. In this configuration, the friction coefficient between the first mold 71 and the second mold 74 and the electrode stack 10 can be increased. Therefore, even with a small clamping force, it is possible to suppress the electrode stack 10 from deviating from the mold 70.

[0118] As mentioned above, although the example of each aspect of this disclosure was demonstrated referring drawings, this disclosure is not limited to the said aspect.

[0119] For example, although the example in which welded end portion 23 is formed outside the edge of current collector 15 is shown, welded end portion 23 may be formed along the edge of current collector 15 or may be formed inside the edge of current collector 15 .

[0120] In addition, although a rectangular active material layer is illustrated, the shape of the active material layer is not particularly limited as long as it can be regarded as a rectangle. For example, the active material layer can also be divided into a plurality of regions separated from each other, or can be other shapes other than a rectangle. In this case, the shape of the active material layer can be regarded as a rectangle having a long side along the long side of the collector and a short side along the short side of the collector, which is the smallest rectangle containing all regions where the active material layer is formed.

[0121] In addition, although an example is shown in which the first thin-walled portion is formed at both ends of the main body 51 in the X-axis direction, the first thin-walled portion may be formed only at one end of the main body 51 in the X-axis direction. In addition, although an example is shown in which the first thin-walled portion is formed in the entire region in the Z-axis direction at the end of the main body 51 in the X-axis direction, the first thin-walled portion may be formed only in a portion in the X-axis direction. That is, the size of the first thin-walled portion in the Z-axis direction may be smaller than the size of the main body in the Z-axis direction.

[0122] In addition, although the spacer 22 having both the outer edge and the inner edge being rectangular is illustrated, the planar shape of the spacer 22 is not limited thereto. For example, the width of the spacer 22 may be larger than the width of the seal 21 in the region along the outer side surface 20sA within the range of the mold in the X-axis direction, and smaller than the width of the seal 21 in the region deviating from the range of the mold in the X-axis direction. That is, the inner edge of the spacer 22 may be located inwardly of the inner edge of the seal 21 in the region along the outer side surface 20sA within the range of the mold, and may be located outwardly of the inner edge of the seal 21 in other regions.

[0123] In addition, although an example is shown in which the thickness L2 of the main body 51 in the Y-axis direction is 2.0±0.5 mm, the thickness L2 of the main body 51 may be larger or smaller. In addition, as the thickness of the protruding frame 53 in the Y-axis direction, although an example of about 0.5 mm to 6.0 mm is shown, the thickness of the protruding frame 53 is not limited to this. In addition, although an example is shown in which the thickness L1 of the first thin-walled portion 59 is less than 1 / 3 of the thickness L2 of the main body 51, the thickness L1 of the first thin-walled portion 59 is not limited to this, and for example, it may be about 1 / 2 of the thickness L2 of the main body 51. In addition, as a specific example of the thickness L1 of the first thin-walled portion 59, although 0.5 mm is illustrated, the thickness L1 is not limited to this.

[0124] Description of Reference Numerals

[0125] 1…power storage module; 10…electrode stack; 11…bipolar electrode (electrode); 12…positive terminal electrode (electrode); 13…negative terminal electrode (electrode); 15…current collector; 20…sealing body; 20sA…outer side surface (liquid injection port surface); 21…seal (frame-shaped member); 22…spacer (frame-shaped member); 24…end seal (seal, frame-shaped member); 27…connecting hole; 50, 150, 250…injected resin portion; 51…main body portion; 53…protruding frame portion; 55…first overhang portion; 57…second overhang portion.

Claims

1. A power storage module, characterized in that: An electrode stack including a plurality of electrodes stacked along a first direction, the electrode stack including a sealing body provided so as to form an internal space between adjacent electrodes and seal the internal space; and an injection resin portion which is joined to the closure body, The plurality of electrodes include a plurality of current collectors that are rectangular when viewed from the first direction, The enclosure comprises: a welded end portion, which is formed by welding the outer peripheries of a plurality of frame-shaped members stacked in the first direction and interposed between the collectors adjacent to each other in the first direction, the welded end portion having four outer side surfaces surrounding the plurality of collectors and extending along the first direction when viewed from the first direction, The enclosure has: A first end surface and a second end surface, which are two end surfaces of the electrode stack in the first direction; a liquid injection port surface which is one of the four outer side surfaces and to which the injection resin portion is joined; and A plurality of communication holes, which connect the outer side of the injection port surface with the plurality of internal spaces, respectively. The resin injection unit comprises: a main body having a plurality of openings respectively connected to the plurality of communicating holes and partially covering the injection port surface; a first overhanging portion connected to the main body portion and partially covering the first end surface; as well as a second overhanging portion connected to the main body portion and partially covering the second end surface, The main body includes a plurality of protruding frame portions protruding in a second direction intersecting the injection port surface, The plurality of protruding frame portions surround each of the plurality of openings when viewed from the second direction.

2. The power storage module according to claim 1, wherein: The injection resin portion includes a first thin-walled portion, the first thin-walled portion is connected to the main body portion, and is joined to the injection port surface from the main body portion along the injection port surface. The thickness of the first thin-walled portion in the second direction is smaller than the thickness of the main body portion in the second direction.

3. The power storage module according to claim 1 or 2, wherein: The injected resin portion has a second thin-walled portion, the second thin-walled portion is connected to the first overhanging portion, and is joined to the first end surface along the first end surface from the first overhanging portion. The thickness of the second thin-walled portion in the first direction is smaller than the thickness of the first overhanging portion in the first direction.

4. The power storage module according to any one of claims 1 to 3, wherein: The plurality of current collectors include: a first region which is disposed at the center when viewed from the first direction and has an active material layer formed thereon; and a second region which is frame-shaped and located outside the first region. The frame-shaped component comprises: a plurality of sealing members in a frame shape, disposed in the second region of each of the plurality of current collectors; as well as A plurality of spacers are interposed between the sealing members adjacent to each other in the first direction, and define the internal space between the current collectors adjacent to each other in the first direction together with the plurality of spacers.

5. A method for manufacturing a power storage module, characterized in that: The method comprises: preparing an electrode stack including a plurality of electrodes stacked along a first direction, wherein two end surfaces in the first direction are first end surfaces and second end surfaces; a step of providing a welded end portion on the electrode stack so as to form an internal space between adjacent electrodes; and The step of providing an injection resin portion at the welded end portion, The plurality of electrodes include a plurality of current collectors that are rectangular when viewed from the first direction, The step of providing the welded end portion includes the step of welding the outer peripheral edges of a plurality of frame-shaped members stacked in the first direction and interposed between the current collectors adjacent to each other in the first direction to each other. One of the four outer side surfaces of the welded end portion on the side opposite to the inner space, namely, the liquid injection port surface, has a plurality of communication holes connected to the plurality of inner spaces, respectively. The process of setting up the resin injection unit includes: A step of assembling a mold that partially covers the injection port surface to the electrode stack in such a manner that a continuous molding space is formed between a main body region including the plurality of communicating holes in the injection port surface, a first overhang region connected to the main body region and partially extending from the first end surface of the electrode stack, and a second overhang region connected to the main body region and partially extending from the second end surface of the electrode stack; as well as A step of injecting a resin into the molding space of the mold mounted on the electrode stack.

6. The method for manufacturing a power storage module according to claim 5, wherein: In the step of assembling the mold, a first thin-walled space connected to the molding space and extending from the molding space along the injection port surface is formed. The thickness of the first thin-walled space in a second direction intersecting the injection port surface is smaller than the thickness of the formed space in the main body region in the second direction.

7. The method for manufacturing a power storage module according to claim 5 or 6, wherein: In the step of assembling the mold, a second thin-walled space connected to the forming space and extending from the first overhanging area along the first end surface is formed. A thickness of the second thin-walled space in the first direction is smaller than a thickness of the forming space in the first overhanging region in the first direction.

8. The method for manufacturing a power storage module according to any one of claims 5 to 7, wherein: The current collector comprises: a first region which is arranged at the center of the current collector when viewed from the first direction and has an active material layer formed thereon; and a second region which is frame-shaped and located outside the first region. The frame-shaped component comprises: a plurality of sealing members in a frame shape, disposed in the second region of each of the plurality of current collectors; as well as a plurality of spacers interposed between the sealing members adjacent to each other in the first direction and defining the internal space between the current collectors together with the plurality of sealing members; The electrode stack includes a plurality of separators disposed between the current collectors adjacent to each other in the first direction, wherein an outer edge of each of the plurality of separators is disposed between the plurality of sealants and the plurality of spacers. In the step of assembling the mold, a region of the electrode stack where the plurality of current collectors, the plurality of sealants, the plurality of spacers, and the plurality of separators overlap when viewed from the first direction is sandwiched by the mold.

9. The method for manufacturing a power storage module according to any one of claims 5 to 8, wherein: The mold includes a first mold and a second mold that clamp the electrode stack from a first direction. The surface roughness of the surface of the first mold that contacts the electrode stack and the surface of the second mold that contacts the electrode stack is greater than the surface roughness of the surface of the mold that forms the molding space.

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