Power storage module

Abstract

A power storage module is provided with an electrode laminate, a closed body provided on the electrode laminate, and a frame member formed separately from the closed body and joined to the closed body. The closed body includes a welded end portion formed by welding end portions of a seal and a spacer, and a communication hole having an opening in an outer side surface of the welded end portion, the frame member includes a frame portion surrounding the opening of the communication hole, and the frame portion includes: a first end surface joined to the outer side surface so as to surround the opening, and a second end surface joined to the outer side surface so as to surround the opening; and a second end surface, which is an end surface on the opposite side from the first end surface, and which is formed so as to surround the opening.

Description

Technical Field

[0001] The present disclosure relates to a power storage module. Background Art

[0002] Patent document 1 describes a storage module. The storage module includes an electrode stack including a plurality of electrodes stacked with an insulator therebetween and a sealing body arranged in a manner surrounding the electrode stack. The sealing body includes a first resin portion arranged at the peripheral portion of the electrode plate and a second resin portion arranged on the outside of the plurality of first resin portions in a manner surrounding the plurality of first resin portions. The sealing body is provided with a plurality of connecting holes connected to different internal spaces formed between the electrodes. The connecting holes are used, for example, to supply electrolyte to the internal space. A plurality of connecting hole regions each having the same number of connecting holes is formed in one of the four wall portions constituting the sealing body. In the storage module, the electrolyte is supplied to the internal space while the front end face of the nozzle of the electrolyte supply device is pressed against the connecting hole region of the sealing body through a gasket. At this time, the gasket is strongly compressed in a plurality of protrusions arranged in the connecting hole region in a manner that surrounds each of the plurality of connecting holes.

[0003] Patent document 2 describes a power storage module. The power storage module includes an electrode stack including a plurality of electrodes stacked with an insulator therebetween, a frame arranged to surround the electrode stack, and a pressure regulating valve mounted on the frame. The frame includes a first closing portion provided at the peripheral portion of the electrode plate and a second closing portion provided at the outer side of the first closing portion. A plurality of installation areas for mounting the pressure regulating valve are provided on a wall portion constituting the frame. In each installation area, the frame is provided with a connecting hole connected to an internal space formed between the electrodes. The connecting hole is used, for example, to supply an electrolyte to the internal space. In the power storage module, the connecting hole can be closed by installing a pressure regulating valve in the installation area. The frame is provided with a frame-shaped protrusion in the installation area for joining with the pressure regulating valve by heat welding.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-035665

[0007] Patent Document 2: Japanese Patent Application Publication No. 2021-009795 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] In Patent Documents 1 and 2, a frame-shaped ridge and a protrusion are formed together with the second resin portion and the second closed portion by injection molding. As a specific example, a frame-shaped protrusion is formed together with the second closed portion by insert molding in which a stacked body composed of electrode plates provided with a first closed portion is arranged in an injection molding mold and resin is injected. At this time, the resin injected into the mold flows on the entire outer side including the opening of the connecting hole of the first closed portion. As a result, there is a possibility that the connecting hole is blocked by the resin, resulting in reduced reliability.

[0010] An object of the present disclosure is to provide a power storage module capable of suppressing a decrease in reliability.

[0011] Solutions for solving problems

[0012] The power storage module disclosed herein comprises: an electrode stack including a plurality of electrodes, the electrodes including a current collector and an active material layer formed on the current collector, the plurality of electrodes being stacked along a first direction; a sealing body provided on the electrode stack in a manner of forming an internal space between adjacent current collectors and sealing the internal space; an electrolyte solution contained in the internal space; and a frame member which is separately constituted from the sealing body and joined to the sealing body, the sealing body comprising: a plurality of frame-shaped sealing members provided at the peripheral edge portions of the plurality of current collectors respectively; a plurality of spacers interposed between the sealing members adjacent to each other in the first direction, forming an internal space between the current collectors together with the plurality of spacers; space; a welding end portion, which is formed by welding ends of multiple seals and multiple spacers on the side opposite to the internal space; and a connecting hole, which is connected to each of the multiple internal spaces and has an opening on the outer side surface of the welding end portion on the side opposite to the internal space, the frame member includes multiple frame portions surrounding the openings of each of the multiple connecting holes when viewed from a second direction intersecting the outer side surface, and the multiple frame portions each have: a first end face, which is joined to the outer side surface in a manner of surrounding the openings of each of the multiple connecting holes when viewed from the second direction; and a second end face, which is an end face on the side opposite to the first end face, and is formed in a manner of surrounding the openings of each of the multiple connecting holes when viewed from the second direction.

[0013] In the power storage module, a connecting hole connected to the internal space between the current collectors of the electrodes is provided in a closing body provided in the electrode stack. The closing body includes a sealing member provided in the peripheral portion of the current collector and a fused end portion formed by fusion of the end portion of the spacer between the sealing members. The opening of the above-mentioned connecting hole is formed on the outer side surface of the fusion end portion. In addition, a frame member having a frame portion surrounding the opening of the connecting hole at the outer side surface of the fusion end portion is provided in the closing body. Therefore, for example, during the injection of the electrolyte, closure can be achieved by pressing the nozzle, and the frame member can be used when joining other members to the closing body. In addition, in the power storage module, the frame member is constructed separately from the closing body, and is joined to the closing body at the portion surrounding the opening of the connecting hole on the outer side surface. As a result, unlike the case where the frame member and the closing body are formed integrally by injection molding, it is not easy to cause such a defect that the connecting hole is blocked by the resin used for injection molding. Therefore, the reduction in reliability is suppressed.

[0014] In the storage battery module disclosed herein, the frame member may further include a flange protruding from the end of each of the first end face side of the plurality of frame parts along the outer side surface and joined to the outer side surface. According to this structure, for example, when the nozzle of the electrolyte injection device is pressed against the frame member, or when another member is joined to the frame member, the stress applied to the end face of the frame member is dispersed to the frame part and the flange, thereby reducing the stress applied to the closed body side. Therefore, compared with the case where the frame member does not have a flange, damage to the structure on the closed body side can be suppressed, and the surface pressure applied to the end face of the frame member can be increased to suppress poor sealing or joining.

[0015] In the power storage module according to the present disclosure, the flange may protrude from the frame toward the inside of the region surrounded by the frame when viewed from the second direction. In this case, the above-mentioned effect of having the flange can be obtained while maintaining the outer dimensions of the frame member.

[0016] In the power storage module involved in the present disclosure, it is also possible to have a plurality of frame members arranged along the third direction, the third direction being a direction intersecting the first direction and the second direction and along the outer side surface, each of the plurality of frame members is arranged in a manner that the frame portion surrounds a group of openings that are different from each other and are arranged along the first direction when viewed from the second direction, and the flange protrudes from the frame portion along the third direction. In this way, by using a plurality of frame members and providing the flange on each frame member, the stress applied to the closed body side can be reliably reduced.

[0017] In the power storage module disclosed herein, the plurality of frame members may include a frame member having an asymmetric shape in the first direction by including at least two frame portions of different sizes in the first direction. In this case, the position of the area surrounded by the frame portion in the first direction can be changed when the frame member is arranged in a manner such that one of the two frame portions of different sizes in the first direction faces one side (e.g., the upper side) of the first direction relative to the other frame portion and when the frame member is arranged in the opposite direction. Thus, the openings of the plurality of communication holes of different positions in the first direction can be surrounded in a manner that does not interfere with each other by fewer types of frame members (i.e., while reducing the number of components).

[0018] In the battery module disclosed herein, the enclosure may be made of resin, and the frame member may be made of a resin having the same main component as the main component of the resin of the enclosure and having a higher melting point than the resin of the enclosure. In this case, when the frame member is joined to the enclosure by welding, for example, deformation of the frame member caused by shrinkage is suppressed.

[0019] Effects of the Invention

[0020] According to the present disclosure, it is possible to provide a power storage module capable of improving reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic cross-sectional view of the power storage module according to the present embodiment.

[0022] Figure 2 Yes Figure 1 The illustrated schematic cross-sectional view is an enlarged view of a portion of the power storage module.

[0023] Figure 3 yes Figure 1 A schematic side view of a storage module is shown.

[0024] Figure 4 It is shown Figure 1 Schematic cross-sectional views of several examples of frame members are shown.

[0025] Figure 5 It is used to illustrate Figure 1 to Figure 4 A schematic cross-sectional view showing one step of a method for manufacturing a power storage module shown.

[0026] Figure 6 It is used to illustrate Figure 1 to Figure 4 A schematic cross-sectional view showing one step of a method for manufacturing a power storage module shown.

[0027] Figure 7 It is a schematic plan view showing a frame member according to a modified example.

[0028] Figure 8 yes Figure 7 A schematic cross-sectional view of the frame member is shown.

[0029] Fig. 9 It shows the settings Figure 7 , Figure 8 The figure shows the process of making the frame member.

[0030] Fig.10 It shows the settings Figure 7 , Figure 8 The figure shows the process of making the frame member. DETAILED DESCRIPTION

[0031] Hereinafter, an embodiment will be described with reference to the accompanying drawings. In the description of the accompanying drawings, the same reference numerals are used for the same or equivalent elements, and repeated descriptions are sometimes omitted. An orthogonal coordinate system defined by a coordinate axis representing a first direction D1, a coordinate axis representing a second direction D2, and a coordinate axis representing a third direction D3 is shown.

[0032] Figure 1 It is a schematic cross-sectional view of the power storage module according to the present embodiment. Figure 1 The power storage module 1 shown is, for example, a power storage module used in batteries of various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage module 1 is, for example, a secondary battery such as a nickel-hydrogen secondary battery or a lithium-ion secondary battery. The power storage module 1 may also be a double-layer capacitor or an all-solid-state battery. Here, the case where the power storage device 1 is a lithium-ion secondary battery is exemplified.

[0033] The power storage module 1 includes an electrode stack 10, a sealing body 20, a frame member 30, and a sheet member 40. The electrode stack 10 includes a plurality of electrodes stacked along a first direction D1. The first direction D1 is a stacking direction of the electrodes and is a 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 mutually adjacent electrodes. The electrode stack 10 is formed by stacking a plurality of bipolar electrodes 11 between the positive terminal electrode 12 and the negative terminal electrode 13.

[0034] 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, for example, in the form of a rectangular sheet. The current collector 15 includes a first main surface 15a as one surface, and a second main surface 15b as another surface on the side opposite to the first main surface 15a. That is, the current collector 15 has a first main surface 15a and a second main surface 15b that are opposite to each other in the stacking direction D. The positive electrode active material layer 16 is provided on the first main surface 15a of the current collector 15. The negative electrode active material layer 17 is provided on the second main surface 15b of the current collector 15. A plurality of bipolar electrodes 11 are stacked in such a manner that the positive electrode active material layer 16 of one bipolar electrode 11 is opposite to the negative electrode active material layer 17 of another bipolar electrode 11. Here, the first main surface 15 a of the current collector 15 is a surface facing one direction in the first direction D1 , and the second main surface 15 b of the current collector 15 is a surface facing the other direction in the first direction D1 .

[0035] The positive electrode active material layer 16 and the negative electrode active material layer 17 are rectangular when viewed from the first direction D1. The negative electrode active material layer 17 is slightly larger than the positive electrode active material layer 16 when viewed from the first direction D1. That is, when viewed from above from the first direction D1, the entire formation area of ​​the positive electrode active material layer 16 is located within the formation area of ​​the negative electrode active material layer 17.

[0036] The positive terminal electrode 12 has a current collector 15 and a positive electrode active material layer 16 provided on a first main 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 main surface 15b of the current collector 15. That is, no active material layer is provided on the second main surface 15b of the current collector 15 of the positive terminal electrode 12. The second main surface 15b of the current collector 15 of the positive terminal electrode 12 serves as a positive terminal surface of the power storage module 1. The positive terminal electrode 12 is stacked on the bipolar electrode 11 at an end portion on one side of the electrode stack 10 in the first direction D1. 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.

[0037] The negative terminal electrode 13 includes a current collector 15 and a negative electrode active material layer 17 provided on a second main surface 15b of the current collector 15. The negative terminal electrode 13 does not include a positive electrode active material layer 16 and a negative electrode active material layer 17 on a first main surface 15a of the current collector 15. That is, no active material layer is provided on the first main surface 15a of the current collector 15 of the negative terminal electrode 13. The first main surface 15a of the current collector 15 of the negative terminal electrode 13 serves as a negative terminal surface of the power storage module 1. The negative terminal electrode 13 is stacked on the bipolar electrode 11 at the end portion on the other side of the first direction D1 of the electrode stack 10. That is, the negative terminal electrode 13 is arranged on the side opposite to the positive terminal electrode 12 with respect to the plurality of bipolar electrodes 11. 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.

[0038] The separator 14 is respectively arranged between the bipolar electrodes 11 adjacent to each other in the first direction D1, 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. The separator 14 prevents a short circuit caused by contact between adjacent electrodes by isolating the positive electrode active material layer 16 from the negative electrode active material layer 17, and allows charge carriers such as lithium ions to pass through.

[0039] 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 to which a conductive filler is added as needed in a non-conductive polymer material 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.

[0040] A coating layer may also be formed on the surface of the current collector 15. The coating layer may be formed, for example, 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. The current collector 15 may also be a current collector formed by integrating alloy foils of the above-mentioned metals or multiple sheets of the above-mentioned metal foils by laminating them. 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. In addition, for example, the thickness of some of the current collectors 15 of the bipolar electrode 11, the positive terminal electrode 12, and the negative terminal electrode 13 may be 100 μm or more. In this case, the structural stability of the electrode stack 10 is improved.

[0041] 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.

[0042] 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 of a simple substance, an alloy, or a compound. Examples of the negative electrode active material include lithium (Li), carbon, and metal compounds. The negative electrode active material can also be an element or a compound thereof that can be alloyed with lithium. Examples of carbon include natural graphite, artificial graphite, hard carbon (difficult to graphitize carbon), or soft carbon (easy to graphitize carbon). Examples of artificial graphite include highly oriented graphite and mesophase carbon microbeads. Examples of elements that can be alloyed with lithium include silicon (silicon) or tin. In the present embodiment, the negative electrode active material layer 17 contains graphite as a carbon-based material.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] The closing body 20 is formed in a frame shape at the peripheral portion of the electrode stack 10 in a manner surrounding the electrode stack 10. The closing body 20 can be joined to each of the first main surface 15a and the second main surface 15b of the current collector 15 at the peripheral portion 15c of each current collector 15. The closing body 20 is used to form an internal space S between the current collectors 15 adjacent to each other in the first direction D1 and to close each of the internal spaces S. An electrolyte is contained in each internal space S (not shown). That is, the closing body 20, together with the current collectors 15 adjacent to each other in the first direction D1, defines the internal space S for containing the electrolyte. The closing body 20 prevents the electrolyte from penetrating to the outside.

[0048] The sealing body 20 suppresses the intrusion of moisture, gas, etc. from the outside of the electrode stack 10 into the internal space S and suppresses the leakage of the electrolyte contained in the electrode stack 10 to the outside. The edge of the separator 14 is bonded to the sealing body 20. The sealing body 20 includes an insulating material. As the material of the sealing body 20, various resin materials such as polypropylene, polyethylene, polystyrene, ABS resin, acid-modified polypropylene, acid-modified polyethylene, and acrylonitrile styrene resin can be listed.

[0049] The sealing body 20 includes a plurality of seals 21, a plurality of spacers 22, and a welded end portion 23. The seal 21 is provided on each current collector 15. Therefore, the seals 21 are stacked one on another along the first direction D1. The seal 21 is frame-shaped and is provided on the peripheral portion 15c of the current collector 15. That is, the seal 21 is provided in a manner from the first main surface 15a of the current collector 15 through the end surface to the second main surface 15b, and covers the peripheral portion 15c. The seal 21 can be welded to at least one of the first main surface 15a and the second main surface 15b of the current collector 15.

[0050] The spacer 22 is arranged so as to be interposed between the seals 21 adjacent in the first direction D1. Thus, the spacer 22 is maintained in the space between the seals 21 adjacent in the first direction D1, that is, between the collectors 15 adjacent in the first direction D1. The spacer 22 is in the shape of a frame having an inner peripheral end face and an outer peripheral end face, and is arranged on the peripheral portion 15c of the collector 15 as viewed from the first direction D1. Here, the end of the spacer 14 is sandwiched between the seal 21 and the spacer 22 and fixed. The end of the spacer 14 can be fused to at least one of the seal 21 and the spacer 22.

[0051] The welded end portion 23 is formed by welding and integrating the ends of the plurality of seals 21 and the plurality of spacers 22 on the side opposite to the internal space S. More specifically, the portions of the plurality of seals 21 and the plurality of spacers 22 located outside the current collector 15 as viewed from the first direction D1 are welded to each other to form the welded end portion 23. The welded end portion 23 is frame-shaped in a manner surrounding the electrode stack 10 as viewed from the first direction D1. The outer side surface 23s of the welded end portion 23 on the side opposite to the internal space S extends along the first direction D1 and constitutes the outer side surface of the sealing body 20.

[0052] In addition, the sealing body 20 has a thickened portion 25. The thickened portion 25 is arranged on the surface of the outer side of the seal 21 of the collector 15 provided in the positive terminal electrode 12 and the negative terminal electrode 13 in the first direction D1. The thickened portion 25 is joined to the seal 21. The end of the thickened portion 25 located at the outer side of the collector 15 as viewed from the first direction D1 is welded to the end of the seal 21, and constitutes a part of the welded end 23. The outer shape of the sealing body 20 when viewed from the first direction D1 is polygonal, including the respective sides of the polygon. For example, when the outer shape of the sealing body 20 when viewed from the first direction D1 is a quadrilateral, the sealing body 20 includes 4 sides. The connecting hole 27 described later is provided to one of the multiple sides of the sealing body 20. And, here, the thickened portion 25 is provided only on the side where the connecting hole 27 is provided.

[0053] In addition, a conductive member 50 that functions as a terminal for extracting current from the power storage module 1 is arranged and electrically connected to the first main surface 15a of the collector 15 of the positive terminal electrode 12 and the second main surface 15b of the collector 15 of the negative terminal electrode 13, which is exposed from the sealing body 20. The conductive member 50 can be used to electrically connect a plurality of power storage modules 1. In addition, the conductive member 50 can also be used as a restraining member to apply a restraining load to the electrode stack 10. Moreover, a cooling flow path can also be formed in the conductive member 50. By flowing a cooling medium in the cooling flow path formed in the conductive member 50, the electrode stack 10 can be cooled.

[0054] The frame member 30 is formed separately from the sealing body 20 and joined to the sealing body 20. Here, the frame member 30 is joined (for example, welded) to the outer side surface 23s of the weld end portion 23 which is the outer side surface of the sealing body 20. The frame member 30 extends from one thickened portion 25 (the thickened portion 25 on the positive terminal electrode 12 side) to another thickened portion 25 (the thickened portion 25 on the negative terminal electrode 13 side) in the first direction D1. Therefore, the outer edge of the frame member 30 in the first direction D1 is located on the thickened portion 25, and as an example, is consistent with the outer edge of the thickened portion 25. The sheet member 40 is joined (bonded) to the end surface 30s of the frame member 30 on the opposite side to the sealing body 20. The sheet member 40 is, for example, a laminated film. Next, the details of the frame member 30 will be described.

[0055] Figure 2 Yes Figure 1 The illustrated schematic cross-sectional view is an enlarged view of a portion of the power storage module. Figure 3 yes Figure 1 A schematic side view of a storage module is shown. Figure 4 (a) is along Figure 3 A schematic cross-sectional view of the line IV-IV. Figure 3In (a), a state in which the frame member 30 is not provided in the enclosure 20 is shown. Figure 3 In (b), a state where a frame member 30 is provided in the enclosure 20 is shown. Figure 2 , Figure 3 as well as Figure 4 As shown in (a) of FIG. 1 , the sealing body 20 is formed with a communication hole 27 that communicates with each of the plurality of internal spaces S. As shown in FIG.

[0056] As an example, the connecting hole 27 is formed by cutting off a portion of the spacer 22 and passing through the spacer 22 and the welded end portion 23. The connecting hole 27 has one opening in the internal space S and another opening 27h on the outer side surface 23s of the welded end portion 23. In the power storage module 1, a single cell (cell) C including one internal space S is formed by a pair of adjacent collectors 15. Here, one connecting hole 27 is formed for one single cell C. When viewed from the second direction D2 intersecting (orthogonal) to the outer side surface 23s (refer to Figure 3 (a)), the opening 27h of the communication hole 27 is arranged so that its position in the third direction D3 is different for each single cell C. The third direction D3 is a direction intersecting the first direction D1 and the second direction D2, and is a width direction of the power storage module 1 along the outer side surface 23s.

[0057] As an example, the positions of the openings 27h in the third direction D3 are set to be different from the single cell C on one end side of the first direction D1 to the single cell C on the other end side. Therefore, here, the plurality of openings 27h having substantially the same position in the third direction D3 are provided corresponding to every other single cell C and are arranged along the first direction D1. In other words, here, the plurality of openings 27h include a group of openings 28 arranged along the first direction D1 and another group of openings 29 arranged along the first direction D1 at positions different from the openings 28 in the third direction D3, as viewed from the second direction D2.

[0058] The frame member 30 is joined (for example, welded) to the outer side surface 23s of the welded end portion 23. The frame member 30 includes a plurality of frame portions 31 that surround the openings 27h of each of the plurality of communicating holes 27 as viewed from the second direction D2. Here, a plurality of frame members 30 are used. The plurality of frame members 30 are arranged separately from each other along the third direction D3. Here, the plurality of frame portions 31 of one frame member 30 are each arranged in a manner that surrounds each of the openings 28 in a group of openings 28, and the plurality of frame portions 31 of another frame member 30 are each arranged in a manner that surrounds each of the openings 29 in another group of openings 29. That is, the plurality of frame members 30 are each arranged in a manner that surrounds a group of openings 28, 29 that are a group of openings 27h that are different from each other and that are arranged in the first direction D1 as viewed from the second direction D2, through the frame portions 31.

[0059] The frame portion 31 includes: a first end face 31a, which is joined (e.g., welded) to the outer side surface 23s in a manner that surrounds the openings 27h of each of the plurality of connecting holes 27 as viewed from the second direction D2; and a second end face 31b, which is an end face on the side opposite to the first end face 31a, and is formed in a manner that surrounds the openings 27h of each of the plurality of connecting holes 27 as viewed from the second direction D2. Each frame member 30 also includes a flange 32 that protrudes from the end portion on the side of the first end face 31a of the frame portion 31 along the outer side surface 23s and is joined (e.g., welded) to the outer side surface 23s. Here, the frame portion 31 is in the shape of a rectangular frame. Therefore, the area 33 surrounded by the frame portion 31 is rectangular in shape as viewed from the second direction D2. The bottom surface of the area 33 is set to be the outer side surface 23s (the outer side surface of the closed body 20) of the welded end portion 23. In this example, the flange 32 protrudes along the third direction D3 from the portion of the frame portion 31 extending along the first direction D1 toward the inside of the region 33 surrounded by the frame portion 31 as viewed in the second direction D2. As viewed in the second direction D2, the flange 32 is formed in each region 33 so as to be separated from the opening 27h (i.e., does not reach the opening 27h).

[0060] However, if Figure 4 As shown in (b), the flange 32 may be provided in a manner of protruding from a portion of the frame portion 31 extending along the first direction D1 toward the outside of the region 33 surrounded by the frame portion 31 along the third direction D3. Figure 4 As shown in (c), the flange 32 may be provided so as to protrude toward both the inner side and the outer side of the region 33 surrounded by the frame portion 31. Figure 3 As shown in (b), in the frame member 30, another flange 34 may be provided in a manner protruding along the first direction D1 from a portion of the frame portion 31 extending along the third direction D3 toward the inside of the region 33 surrounded by the frame portion 31. In this case, the flange 34 is also formed in each region 33 to be separated from the opening 27h (that is, not reaching the opening 27h) when viewed from the second direction.

[0061] Refer again Figures 2 to 4In one frame member 30, a plurality of (three in the illustrated example) regions 33 arranged along the first direction D1 are divided by a plurality of frame portions 31, and in each region 33, there is an opening 27h of the connecting hole 27 as viewed from the second direction. In addition, the frame member 30 has an end face 30s (a second end face 31b) on the side opposite to the outer side face 23s of the welded end portion 23 (i.e., on the side opposite to the closed body 20). Therefore, as described later, by introducing the electrolyte from the nozzle of the electrolyte injection device in a state where the nozzle is in close contact with the end face 30s, the electrolyte can be injected into the internal space S from the connecting hole 27 connected to each region 33 via the opening 27h.

[0062] The sheet member 40 is joined (eg, bonded) to the end surface 30 s to close the region 33 (ie, the internal space S). In the power storage module 1 , one sheet member 40 may be provided across a plurality of frame members 30 or one sheet member 40 may be provided for each frame member 30 .

[0063] Here, if Figure 3 As shown in (b), the plurality of frame members 30 have an asymmetric shape in the first direction D1 by including at least two frame portions 31 having different sizes in the first direction D1. Here, for one frame member 30, the size of one frame portion 31 (i.e., region 33) among the three frame portions 31 is set larger in the first direction D1 than the sizes of the other two frame portions 31 (i.e., region 33) in the first direction D1.

[0064] Furthermore, such asymmetric multiple frame members 30 are arranged in different directions (inverted in the first direction D1). As a result, the position of the area 33 surrounded by the frame portion 31 in the first direction D1 is different between the frame members 30 with different directions. As a result, the openings 27h of the multiple communication holes 27 with different positions in the first direction D1 can be surrounded by fewer types of frame members 30.

[0065] The frame member 30 as described above can be formed of a resin having a higher melting point than the melting point of the resin of the enclosure 20. In addition, the resin of the enclosure 20 and the resin of the frame member 30 can use resins with the same main agent. As an example, in the case where the enclosure 20 is formed of low-density polyethylene, the frame member 30 can be formed of high-density polyethylene. In addition, the so-called frame member 30 can be formed of a resin having a higher melting point than the melting point of the resin of the enclosure 20, and in the case where the enclosure 20 is composed of multiple resins, it can also include the case where the frame member 30 is formed of a resin having a higher melting point than the melting point of at least one of the multiple resins constituting the enclosure 20. As an example, in the case where the seal 21 in the enclosure 20 is formed of low-density polyethylene, and the spacer 22 and the thickened portion 25 are formed of high-density polyethylene, the frame member 30 can be formed of high-density polyethylene.

[0066] Next, a method for manufacturing the power storage module 1 will be described. Figure 5 and Figure 6 It is used to illustrate Figure 1 to Figure 4 A schematic cross-sectional view of one process of a method for manufacturing a power storage module shown in FIG. Figure 5 As shown in FIG. 1 , an electrode stack 10, a sealing body 20, and a frame member 30 are separately prepared. The sealing body 20 is provided on the electrode stack 10 and integrated. Figure 5 , Figure 6 In FIG. 1 , only a portion of the electrode stack 10 and the sealing body 20 are shown.

[0067] Next, a heater H1 is arranged on the outer side surface (outer side surface 23s of the welded end portion 23) side of the closed body 20. In addition, a heater H2 is arranged on the end surface 30r (first end surface 31a) side of the frame member 30 on the opposite side to the end surface 30s. The heater H1 is a heater with a lower temperature than the heater H2. Next, the closed body 20 is heated by the heater H1, and a portion of the closed body 20 is melted from the outer side surface 23s side. In addition, the frame member 30 is heated by the heater H2, and a portion of the frame member 30 is melted from the end surface 30r side. At this time, as an example, by setting the heater H1 as an infrared heater and setting the heater H2 as a hot plate heater, it is possible to selectively melt only the vicinity of the end surface 30r of the frame member 30, and on the other hand, the closed body 20 can be melted from the outer side surface 23s to a relatively deep position.

[0068] Then, if Figure 6As shown, in a state where a portion of the outer side surface 23s of the closing body 20 and a portion of the end surface 30r of the frame member 30 are melted, the frame member 30 is pressed against the closing body 20, so that a portion of the outer side surface 23s of the closing body 20 and a portion of the end surface 30r of the frame member 30 are melted. Thus, the frame member 30 is welded to the closing body 20.

[0069] Next, the nozzle 60 of the electrolyte injection device is pressed against and closely attached to the end surface 30s of the frame member 30, and the electrolyte is introduced into the region 33 of the frame member 30 from the injection port 61 of the nozzle 60. Thus, the electrolyte is injected into the internal space S of each single cell C from the communication hole 27 connected to each region 33 via the opening 27h of the sealing body 20. Thereafter, the nozzle 60 is removed from the end surface 30s of the frame member 30, and the sheet member 40 is attached to the end surface 30s so as to close the region 33. Thus, the internal space S in which the electrolyte is arranged is closed, and the storage battery module 1 is manufactured.

[0070] As described above, in the power storage module 1, the connecting hole 27 communicating with the internal space S containing the electrolyte between the current collectors 15 of the electrode is provided in the sealing body 20 provided in the electrode stack 10. The sealing body 20 includes a welded end portion 23 formed by welding the seal 21 provided in the peripheral portion 15c of the current collector 15 and the end of the spacer 22 interposed between the seal 21. The opening 27h of the connecting hole 27 is formed on the outer side surface 23s of the welded end portion 23. In addition, the frame member 30 having a frame portion 31 surrounding the opening 27h of the connecting hole 27 at the outer side surface 23s of the welded end portion 23 is provided in the sealing body 20.

[0071] Therefore, for example, when injecting electrolyte, the nozzle 60 can be pressed against the sealing body 20 to achieve sealing, and the frame member 30 can be used when joining other members to the sealing body 20. In addition, in the power storage module 1, the frame member 30 is formed separately from the sealing body 20, and is joined to the sealing body 20 at the portion surrounding the opening 27h of the communication hole 27 of the outer side surface 23s. Therefore, unlike the case where the frame member 30 and the sealing body 20 are integrally formed by injection molding, it is less likely to cause a defect such as clogging of the communication hole 27 by the resin used for injection molding. Therefore, a decrease in reliability is suppressed.

[0072] In addition, in the power storage module 1, the frame member 30 further includes a flange 32 that protrudes from the end portion of the first end face 31a side of each of the plurality of frame portions 31 along the outer side surface 23s and is joined to the outer side surface 23s. Therefore, for example, when the nozzle 60 of the electrolyte injection device is pressed against the frame member 30, or when another member is joined to the frame member 30, the stress applied to the end face 30s of the frame member 30 is dispersed to the frame portion 31 and the flange 32, thereby reducing the stress applied to the sealing body 20 side. Therefore, compared with the case where the frame member 30 does not have the flange 32, damage to the structure on the sealing body 20 side can be suppressed, and the surface pressure applied to the end face 30s of the frame member 30 can be increased to suppress poor sealing or joining.

[0073] In the power storage module 1, the flange 32 protrudes from the frame 31 toward the inside of the region 33 surrounded by the frame 31 as viewed in the second direction D2. Therefore, the above-mentioned effect of having the flange 32 can be obtained while maintaining the outer dimensions of the frame member 30.

[0074] In addition, the storage battery module 1 is provided with a plurality of frame members 30 arranged along the third direction D3, which is a direction intersecting the first direction D1 and the second direction D2 and along the outer side surface 23s. The plurality of frame members 30 are each arranged in such a manner that a group of openings 28 and 29, which are a group of openings 27h different from each other and arranged along the first direction D1 when viewed from the second direction D2, are surrounded by a frame portion 31. Furthermore, the flange 32 protrudes from the frame portion 31 along the third direction D3. In this way, by using a plurality of frame members 30 and providing the flange 32 on each of the frame members 30, the stress applied to the sealing body 20 side can be reliably reduced.

[0075] In addition, in the power storage module 1, the plurality of frame members 30 include a frame member 30 having an asymmetric shape in the first direction D1 by including at least two frame portions 31 having different sizes in the first direction D1. Therefore, when the frame member 30 is arranged so that one of the two frame portions 31 having different sizes in the first direction D1 faces one side (for example, the upper side) in the first direction D1 relative to the other frame portion 31 and when the frame member 30 is arranged in the opposite direction, the position of the region 33 surrounded by the frame portion 31 in the first direction D1 can be changed. Therefore, the openings 27h of the plurality of communication holes 27 having different positions in the first direction D1 can be surrounded by fewer types of frame members 30 (that is, while reducing the number of components) so that the frame portion 31 and the openings 27h do not interfere with each other.

[0076] Furthermore, in the power storage module 1, the sealing body 20 is made of resin, and the frame member 30 is made of resin having a higher melting point than the melting point of the resin of the sealing body 20. In addition, as the resin of the frame member 30, a resin having the same main component as the main component of the resin of the sealing body 20 can be used. Thus, for example, when the frame member 30 is joined to the sealing body 20 by welding, the sealing body 20 to be joined can be melted at a lower temperature, so that when the frame member 30 is pressed against the sealing body 20, it is not heated to a high temperature, and deformation of the frame member 30 caused by thermal expansion and contraction is suppressed.

[0077] The above embodiment is an embodiment for explaining one aspect of the power storage module according to the present disclosure. Therefore, the power storage module according to the present disclosure is not limited to the above power storage module 1, and can be arbitrarily modified.

[0078] For example, in the above embodiment, the case where the frame member 30 is welded to the sealing body 20 is described, but a known method such as bonding using an adhesive can also be used as a method of joining the frame member 30 to the sealing body 20. That is, in the power storage module 1, as long as the frame member 30 formed separately from the sealing body 20 is joined to the sealing body 20.

[0079] In addition, in the above embodiment, the frame member 30 has the flange 32, but the flange 32 is not essential. In addition, the frame member 30 is not limited to the case where it has an asymmetric shape in the first direction D1, and may have a symmetric shape in the first direction D1. Moreover, the frame member 30 may include three or more frame portions 31 of different sizes in the first direction D1.

[0080] Figure 7 It is a schematic plan view showing a frame member according to a modified example. Figure 8 yes Figure 7 A schematic cross-sectional view of the frame member is shown. Figure 8 (a) is along Figure 7 The cross-sectional view of line XIIIa-XIIIa, Figure 8 (b) is along Figure 7 The power storage module 1 may include Figure 7 , Figure 8The frame member 30A shown in the figure replaces the frame member 30 involved in the above embodiment. Compared with the frame member 30 involved in the above embodiment, the frame member 30A is different in that it includes a flange 32a instead of the flange 32, and is consistent with the other aspects. Compared with the flange 32, the flange 32A is different in that the ratio of the length along the height direction (second direction D2) of the frame portion 31 to the protrusion amount (thickness) from the frame portion 31 is set larger (here, longer than the flange 32 in the second direction D2), and is formed in the second direction D2. Such a flange 32A can also be understood as a relatively thick-walled portion formed in the frame portion 31.

[0081] In addition, Figure 7 , Figure 8 In the figure, as an example of the flange 32A, an example of protruding toward the inner side of the area 33 surrounded by the frame portion 31 is shown, but Figure 4 Like the flange 32 shown in (b) and (c) of FIG. 1 , the flange 32A may be provided to protrude toward the outside of the region 33 surrounded by the frame portion 31 , or may be provided to protrude toward both the inside and the outside of the region 33 .

[0082] When the frame member 30A as described above is installed in the enclosure 20, first, Fig. 9 As shown, a heater H1 is arranged on the outer side surface (outer side surface 23s of the welded end portion 23) side of the closed body 20. In addition, a heater H2 is arranged on the end surface 30r (first end surface 31a) side of the frame member 30A on the opposite side to the end surface 30s. Next, the closed body 20 is heated by the heater H1, and a portion of the closed body 20 is melted from the outer side surface 23s side. In addition, the frame member 30A is heated by the heater H2, and a portion of the frame member 30 is melted from the end surface 30r side. At this time, as an example, by setting the heater H1 as an infrared heater and setting the heater H2 as a hot plate heater, it is possible to selectively melt only the vicinity of the end surface 30r of the frame member 30A, and on the other hand, it is possible to melt the closed body 20 from the outer side surface 23s to a relatively deep position.

[0083] Then, if Fig.10As shown, in a state where a part of the outer side 23s side of the closing body 20 and a part of the end face 30r side of the frame member 30A are melted, the frame member 30A is pressed against the closing body 20, and the frame member 30A is pressed into the inside of the closing body 20 from the outer side 23s side of the closing body 20. In the example shown in the figure, the flange 32A as the thick wall portion of the frame member 30A is entirely inserted into the welded end portion 23, and the flange 32A and the welded end portion 23 are melted. Therefore, after this process, the portion other than the flange 32A of the frame portion 31 of the frame member 30A protrudes from the outer side 23s of the closing body 20. However, when the frame member 30A is pressed from the outer side 23s side of the closing body 20, only a part of the flange 32A may be inserted into the welded end portion 23. In this case, the remaining portion of the flange 32A protrudes from the outer side 23s of the closing body 20.

[0084] When the frame member 30A as described above is used, in addition to the same effects as when the frame member 30 according to the above embodiment is used, the following effects can also be achieved. That is, when the frame member 30A is used, when the frame member 30A is welded to the closing body 20, the front end portion of the frame member 30A (at least a portion of the flange 32A) enters the welded end portion 23 of the closing body 20, and the front end portion of the frame member 30A is welded to the closing body 20. Therefore, the front end portion of the frame member 30A can be reliably welded to the welded end portion 23 in an airtight manner.

[0085] In addition, if an attempt is made to press the front end of a frame member that does not have a thick wall portion into the weld end portion 23, the front end of the frame member may be deformed. However, in the frame member 30A, by providing a flange 32A as a thick wall portion, the deformation of the front end portion when the front end of the frame member 30A is pressed into the weld end portion 23 is suppressed. In addition, in the frame member 30A, since a relatively large force is applied to the side portion along the stacking direction (first direction D1) of the seal 21 and the spacer 22 because a plurality of seals 21 and the spacer 22 are pressed in a transverse manner, it is effective to form a flange 32 as a thick wall portion on the side portion for reinforcement.

[0086] The present embodiment is annotated below. The storage module involved in the present disclosure is as follows. [1] "A storage module comprising: an electrode stack including a plurality of electrodes, the electrodes including a current collector and an active material layer formed on the current collector, the plurality of electrodes being stacked along a first direction; a sealing body disposed on the electrode stack in a manner to form an internal space between adjacent current collectors and to seal the internal space; an electrolyte contained in the internal space; and a frame member that is separately constructed from the sealing body and joined to the sealing body, the sealing body comprising: a plurality of frame-shaped seals disposed on the peripheral edge portions of each of the plurality of current collectors; a plurality of spacers interposed between the seals adjacent to each other in the first direction and forming the internal space between the current collectors together with the plurality of seals; and welded end portions. , which is formed by welding the ends of the plurality of seals and the plurality of spacers on the side opposite to the internal space; and a plurality of communicating holes, which are connected to the plurality of internal spaces respectively and have openings on the outer side surface of the welded end portion on the side opposite to the internal space, the frame member includes a plurality of frame portions surrounding the respective openings of the plurality of communicating holes as viewed from a second direction intersecting the outer side surface, and the plurality of frame portions each have: a first end face, which is joined to the outer side surface in a manner of surrounding the respective openings of the plurality of communicating holes as viewed from the second direction; and a second end face, which is an end face on the side opposite to the first end face, and is formed in a manner of surrounding the respective openings of the plurality of communicating holes as viewed from the second direction.

[0087] The power storage module of the present disclosure may also be, [2] "the power storage module according to the above [1], wherein the frame member further includes a flange protruding from the end portion on the first end face side of each of the plurality of frame portions along the outer side surface and joined to the outer side surface."

[0088] The power storage module according to the present disclosure may be [3] "the power storage module according to [2] above, wherein the flange protrudes from the frame toward the inside of the region surrounded by the frame when viewed from the second direction."

[0089] The power storage module involved in the present disclosure may also be, [4] "the power storage module according to the above [2] or [3], wherein it has a plurality of the frame members arranged along the third direction, the third direction being a direction intersecting the first direction and the second direction and along the outer side surface, the plurality of frame members are each arranged in a manner such that the frame portion surrounds a group of openings that are different from each other and are arranged along the first direction when viewed from the second direction, and the flange protrudes from the frame portion along the third direction."

[0090] The power storage module involved in the present disclosure may also be [5] "the power storage module according to the above [4], wherein the plurality of frame members include the frame member having an asymmetric shape in the first direction by including at least two frame portions of different sizes in the first direction."

[0091] The power storage module involved in the present disclosure may also be, [6] "the power storage module according to any one of the above [1] to [5], wherein the sealing body is composed of a resin, and the frame member is composed of a resin whose main component is the same as the main component of the resin of the sealing body and has a higher melting point than the melting point of the resin of the sealing body."

[0092] Description of Reference Numerals

[0093] 1…power storage module, 10…electrode stack, 11…bipolar electrode (electrode), 12…positive terminal electrode (electrode), 13…negative terminal electrode (electrode), 15…current collector, 16…positive electrode active material layer (active material layer), 17…negative electrode active material layer (active material layer), 20…sealing body, 21…sealing member, 22…spacer, 23…welded end, 23s…outer side surface, 27…connecting hole, 27h…opening, 30, 30A…frame member, 30s…end surface, 31…frame portion, 31a…first end surface, 31b…second end surface, 32, 32A…flange, 33…area, D1…first direction, D2…second direction, D3…third direction, S…internal space.

Claims

1. A power storage module, characterized in that: have: An electrode stack comprising a plurality of electrodes, wherein the electrodes include a current collector and an active material layer formed on the current collector, and the plurality of electrodes are stacked along a first direction; a sealing body provided on the electrode stack so as to form an internal space between adjacent current collectors and seal the internal space; an electrolyte contained in the internal space; as well as a frame member which is formed separately from the enclosure and is joined to the enclosure, The enclosure comprises: A plurality of frame-shaped sealing members, which are provided at the peripheral edge of each of the plurality of current collectors; a plurality of spacers interposed between the sealing members adjacent to each other in the first direction and forming the internal space between the current collectors together with the plurality of sealing members; a welded end portion formed by welding ends of the plurality of seal members and the plurality of spacers on a side opposite to the internal space; as well as a plurality of communication holes, each of which is in communication with the plurality of internal spaces and has an opening on the outer side surface of the welded end portion on the side opposite to the internal space; The frame member includes a plurality of frame portions surrounding the respective openings of the plurality of communicating holes when viewed from a second direction intersecting the outer side surface. Each of the plurality of frame portions has: a first end surface joined to the outer side surface so as to surround the openings of the respective communicating holes as viewed from the second direction; and The second end surface is an end surface on the opposite side to the first end surface and is formed so as to surround the openings of the respective communication holes when viewed from the second direction.

2. The power storage module according to claim 1, wherein: The frame member further includes a flange that protrudes from an end portion of each of the plurality of frame portions on the first end surface side along the outer side surface and is joined to the outer side surface.

3. The power storage module according to claim 2, wherein: The flange protrudes from the frame portion toward the inside of a region surrounded by the frame portion when viewed from the second direction.

4. The power storage module according to claim 2, wherein: A plurality of the frame members are arranged along a third direction, wherein the third direction is a direction intersecting the first direction and the second direction and along the outer side surface, The plurality of frame members are each arranged so as to surround, by the frame portion, a group of the openings which are different from each other and are arranged along the first direction when viewed from the second direction. The flange protrudes from the frame portion along the third direction.

5. The power storage module according to claim 4, wherein: The plurality of frame members include the frame member having an asymmetric shape in the first direction by including at least two frame portions having different sizes in the first direction.

6. The power storage module according to any one of claims 1 to 5, wherein: The sealing body is made of resin. The frame member is made of a resin having the same main component as that of the resin of the sealing body and having a higher melting point than that of the resin of the sealing body.

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