Method for manufacturing electric power storage module

Abstract

This method for manufacturing an electric power storage module comprises a first inspection step for inspecting a module to be inspected within a chamber. In the first inspection step, the following inspections are performed simultaneously: a first airtightness inspection between a first cell and a first adjacent cell that includes an internal space adjacent to an internal space of the first cell, among a plurality of cells to be inspected; and a second airtightness inspection between the first cell and a second adjacent cell that includes a frame adjacent to a first cell frame, among the plurality of cells to be inspected.

Description

Energy storage module manufacturing method

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

[0002] Patent Document 1 describes a bipolar battery as a conventional energy storage module. This conventional energy storage module has multiple bipolar electrodes, each with a positive electrode formed on one side of a current collector and a negative electrode formed on the other side. The multiple bipolar electrodes are stacked with separators that hold electrolyte layers interposed between them. A sealing resin is molded and arranged around the outer periphery of the separator.

[0003] JP 2011-151016 A

[0004] In some cases, a sealing body for sealing the internal spaces between the electrodes in an energy storage module has communication holes communicating with the internal spaces, and an electrolyte is injected into each internal space through the communication holes. In this case, prior to injection of the electrolyte, it is necessary to inspect the airtightness between the internal spaces adjacent in the stacking direction of the electrodes.

[0005] In some energy storage modules, multiple liquid filling frames are integrally formed on the outer surface of the sealing body, surrounding the openings of the communication holes that communicate with each of the internal spaces. These liquid filling frames provide, for example, a contact surface with a nozzle of a liquid filling device when injecting the electrolyte. When such liquid filling frames are formed, it is necessary to inspect the airtightness between adjacent frames in addition to inspecting the airtightness between the internal spaces adjacent in the stacking direction.

[0006] Therefore, in the above technical field, it is desirable to improve the productivity of energy storage modules by efficiently inspecting the airtightness between internal spaces adjacent in the stacking direction and between adjacent frames in a liquid filling frame.

[0007] Therefore, an object of the present disclosure is to provide a method for manufacturing an energy storage module that can improve productivity.

[0008] A method for manufacturing an electric storage module according to the present disclosure is a method for manufacturing an electric storage module including: an electrode stack including a plurality of electrodes stacked along a first direction; a sealing body provided on the electrode stack so as to surround the electrode stack and for sealing a plurality of internal spaces formed between the electrodes adjacent in the first direction; and an electrolyte solution contained in the internal spaces, the method including: an arrangement step of arranging a module to be inspected, which is the electric storage module before the electrolyte solution is contained, in a chamber; and a first inspection step of inspecting the module to be inspected in the chamber after the arrangement step, wherein the sealing body has an outer surface facing the side opposite to the internal spaces, a plurality of communication holes that communicate with each of the plurality of internal spaces and have openings on the outer surface of the sealing body, and a plurality of frame portions that are integrally formed on the outer surface having the openings, and each of the plurality of frame portions overlaps with one of the plurality of openings when viewed from the first direction. a first inspection step comprising: a first inspection step of inspecting an airtightness between the first cell and the first adjacent cell; and a second inspection step of inspecting an airtightness between the first cell and the first adjacent cell, the first inspection step being performed simultaneously with an attachment attached to the frame of the first cell.

[0009] In this manufacturing method, a first inspection step is performed with a module to be inspected, which is a power storage module before injection of an electrolyte solution, placed in a chamber. The module to be inspected (power storage module) includes an electrode stack including a plurality of electrodes stacked along a first direction, and a sealing body provided on the electrode stack so as to surround the electrode stack and for sealing a plurality of internal spaces formed between adjacent electrodes in the first direction. A plurality of communication holes communicating with each of the internal spaces are formed in the sealing body, and a plurality of frame portions are integrally formed on an outer surface of the sealing body where the communication holes open. Each of the plurality of frame portions is formed by a predetermined number of frames integrated together while sharing a partition wall in the first direction. Each of the predetermined number of frames surrounds a predetermined number of openings of the communication holes in the outer surface of the sealing body that overlap when viewed from the first direction. For each of the multiple internal spaces, one internal space, one communication hole communicating with the internal space, and one frame surrounding the opening of the communication hole constitute one test cell through which fluid flows.

[0010] In a module to be inspected configured as described above, it is necessary to inspect the airtightness between adjacent internal spaces in the first direction and between adjacent frames (sharing a partition wall) in the first direction. Therefore, in this manufacturing method, in the first inspection step, a first airtightness inspection is performed simultaneously between a first adjacent cell and the first cell, the first adjacent cell including an internal space adjacent in the first direction within the internal space of the first cell among the plurality of inspected cells, and a second airtightness inspection is performed simultaneously between a second adjacent cell and the first cell, the second adjacent cell including a frame adjacent in the first direction and sharing a partition wall with the frame of the first cell among the plurality of inspected cells. In this manner, this manufacturing method is efficient because it simultaneously inspects both the airtightness between adjacent internal spaces in the first direction and the airtightness between adjacent frames in the first direction. Therefore, this manufacturing method improves productivity.

[0011] In the energy storage module manufacturing method according to the present disclosure, the first inspection step may include a step of applying gas to the first cell and measuring whether or not there is a pressure change in at least one of the first adjacent cell and the second adjacent cell.

[0012] In the energy storage module manufacturing method according to the present disclosure, the first inspection process may include a gas inspection process in which a first airtightness inspection and a second airtightness inspection are performed simultaneously by applying gas to the first cell and measuring the presence or absence of gas leaking to the first adjacent cell and the second adjacent cell.

[0013] In the energy storage module manufacturing method according to the present disclosure, the first inspection process may include a vacuum inspection process in which, before the gas inspection process, the first adjacent cell and the second adjacent cell are evacuated and the presence or absence of a pressure change in the first cell is measured, thereby simultaneously performing the first airtightness inspection and the second airtightness inspection.

[0014] In the energy storage module manufacturing method according to the present disclosure, the plurality of test cells may be divided into a plurality of groups each including the first cell, the first adjacent cell, and the second adjacent cell, and the gas inspection process may be performed for each group.

[0015] In the energy storage module manufacturing method according to the present disclosure, the plurality of test cells may be divided into a plurality of groups including the first cell, the first adjacent cell, and the second adjacent cell, and the vacuum inspection process may be performed for each group.

[0016] The energy storage module manufacturing method according to the present disclosure may include a second inspection step, after the placement step and before the first inspection step, in which the chamber is evacuated and the presence or absence of pressure changes in all of the inspected cells is measured.

[0017] The energy storage module manufacturing method according to the present disclosure may include, after the first inspection step, a third inspection step of measuring the amount of gas leakage caused by the pressure difference between all the cells to be inspected and the interior of the chamber.

[0018] According to the present disclosure, it is possible to provide a method for manufacturing an energy storage module that can improve productivity.

[0019] FIG. 1 is a schematic cross-sectional view showing an example of an energy storage module that can be manufactured by the energy storage module manufacturing apparatus according to the present embodiment. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1 . FIG. 3 is a schematic cross-sectional view showing the configuration of the periphery of a communication hole in a sealing body. FIG. 4 is a side view of the sealing body from the outer surface side on which a frame portion is provided. FIG. 5( a) is a schematic side view showing the positional relationship between an internal space and a communication hole, and FIG. 5( b) is a schematic side view showing the positional relationship between a frame portion and a communication hole. FIG. 6 is a schematic partial cross-sectional view showing an energy storage module manufacturing apparatus according to an embodiment. FIG. 7 is a schematic cross-sectional view showing the state of the periphery of a communication hole in an injection step. FIG. 8 is a flowchart showing one step of a method for manufacturing an energy storage module according to the present embodiment. FIG. 9 is a diagram for explaining step S104 shown in FIG. 8 . FIG. 10 is a diagram for explaining step S105 shown in FIG. 8 . FIG. 11 is a flowchart showing one step of a method for manufacturing an energy storage module according to a modified example.

[0020] An energy storage module manufacturing apparatus according to one embodiment will be described below with reference to the drawings. In the description of each figure, identical or corresponding elements are designated by the same reference numerals, and redundant description may be omitted. Each figure may also show an orthogonal coordinate system defined by a coordinate axis indicating a first direction D1, a coordinate axis indicating a second direction D2 intersecting the first direction D1, and a coordinate system indicating a third direction D3 intersecting the first direction D1 and the second direction D2. As an example, the first direction D1 indicates a vertical direction, and the second direction D2 and the third direction D3 are two horizontal directions intersecting each other.

[0021] FIG. 1 is a schematic plan view showing an example of an energy storage module that can be manufactured by the energy storage module manufacturing apparatus according to this embodiment. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1. The energy storage module 1 shown in FIGS. 1 and 2 is a module used in batteries for various vehicles, such as forklifts, hybrid vehicles, and electric vehicles. The energy storage module 1 is, for example, a secondary battery, such as a nickel-metal hydride secondary battery or a lithium-ion secondary battery. The energy storage module 1 may be an electric double layer capacitor or an all-solid-state battery. Here, a case where the energy storage module 1 is a lithium-ion secondary battery will be illustrated as an example.

[0022] The energy storage module 1 includes an electrode stack 2 and a sealing body 3. The electrode stack 2 includes a plurality of electrodes stacked along a first direction D1. The first direction D1 is the stacking direction of the electrodes in the electrode stack 2 and corresponds to the thickness direction of the energy storage module 1. The second direction D2 and the third direction D3 are in-plane directions of a current collector 15, which will be described later. The second direction D2 corresponds to the depth direction of the energy storage module 1, and the third direction D3 corresponds to the width direction of the energy storage module 1.

[0023] The multiple electrodes include multiple bipolar electrodes 11, a positive electrode terminal electrode 12, and a negative electrode terminal electrode 13. A separator 14 is disposed between adjacent electrodes in the stacking direction. The bipolar electrode 11 includes a current collector 15, a positive electrode active material layer 16, and a negative electrode active material layer 17. The current collector 15 has, for example, a rectangular sheet shape. The positive electrode active material layer 16 is provided on a first surface 15a of the current collector 15. The negative electrode active material layer 17 is provided on a second surface 15b of the current collector 15. The first surface 15a of the current collector 15 faces one side of the first direction D1, and the second surface 15b of the current collector 15 faces the other side of the first direction D1.

[0024] In the electrode stack 2, the multiple bipolar electrodes 11 are stacked such that the positive electrode active material layer 16 of one bipolar electrode 11 faces the negative electrode active material layer 17 of another bipolar electrode 11 adjacent to the one bipolar electrode 11. The positive electrode active material layer 16 and the negative electrode active material layer 17 have a rectangular shape when viewed from the first direction D1. In this embodiment, 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, in a plan view viewed from the first direction D1, the entire formation region of the positive electrode active material layer 16 is located within the formation region of the negative electrode active material layer 17.

[0025] 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. No active material layer is provided on a second surface 15b of the current collector 15 in the positive terminal electrode 12. The positive terminal electrode 12 is stacked on the bipolar electrode 11 at one end of the electrode laminate 2 in the first direction D1. The positive electrode active material layer 16 of the positive terminal electrode 12 and the negative electrode active material layer 17 of the bipolar electrode 11 adjacent to the positive terminal electrode 12 face each other. The second surface 15b of the current collector 15 in the positive terminal electrode 12 is exposed from the sealing body 3 as one stack end of the electrode laminate 2.

[0026] The negative electrode terminal electrode 13 has a current collector 15 and a negative electrode active material layer 17 provided on a second surface 15b of the current collector 15. No active material layer is provided on a first surface 15a of the current collector 15 in the negative electrode terminal electrode 13. The negative electrode terminal electrode 13 is stacked on the bipolar electrode 11 at the other end of the electrode laminate 2 in the first direction D1. The negative electrode active material layer 17 of the negative electrode terminal electrode 13 and the positive electrode active material layer 16 of the bipolar electrode 11 adjacent to the negative electrode terminal electrode 13 face each other. The first surface 15a of the current collector 15 in the negative electrode terminal electrode 13 is exposed from the sealing body 3 as the other stack end of the electrode laminate 2.

[0027] A conductive member 18 is disposed on an exposed portion R1 of the first surface 15a of the current collector 15 of the positive terminal electrode 12 that is exposed from the sealing body 3, and on an exposed portion R2 of the second surface 15b of the current collector 15 of the negative terminal electrode 13 that is exposed from the sealing body 3. The conductive member 18 is electrically connected to the electrode stack 2 and functions as a terminal for extracting current from the energy storage module 1. The conductive member 18 also functions as a restraining member that applies a predetermined restraining load to the electrode stack 2. A cooling flow path may be formed in the conductive member 18. By circulating a cooling medium through the cooling flow path, the electrode stack 2 can be efficiently cooled.

[0028] Separators 14 are respectively 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. Separators 14 are disposed between the positive electrode active material layer 16 and the negative electrode active material layer 17 between the electrodes. By isolating the positive electrode active material layer 16 and the negative electrode active material layer 17, the separator 14 serves to prevent short circuits due to contact between adjacent electrodes while allowing charge carriers such as lithium ions to pass through.

[0029] The separator 14 may be impregnated with an electrolyte. Examples of the electrolyte impregnated in the separator 14 include a liquid electrolyte (electrolytic solution) containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. Examples of the electrolyte salt contained in the electrolytic solution include LiClO ４ , LiAsF ６ , LiPF ６ , LiBF ４ , LiCF ３ SO ３ , LiN(FSO ２ ) ２ , LiN(CF ３ SO ２ ) ２ Examples of the non-aqueous solvent include cyclic carbonates, cyclic esters, chain carbonates, chain esters, ethers, etc. Two or more of these solvents may be used in combination.

[0030] The current collector 15 is a chemically inactive electrical conductor for continuously supplying current to the positive electrode active material layer 16 and the negative electrode active material layer 17 during discharge or charge of the lithium ion secondary battery. Examples of materials for the current collector 15 include metal materials, conductive resin materials, and conductive inorganic materials. Examples of conductive resin materials include conductive polymer materials and resins obtained by adding a conductive filler to a non-conductive polymer material as needed. The current collector 15 may have multiple layers. In this case, each layer of the current collector 15 may contain the above-mentioned metal materials, conductive resin materials, etc.

[0031] A coating layer may be formed on the surface of the current collector 15. The coating layer may be formed by, for example, plating, spray coating, or other methods. The current collector 15 may have various shapes, such as a plate, foil (e.g., metal foil), film, or mesh. Examples of metal foils include aluminum foil, copper foil, nickel foil, titanium foil, and stainless steel foil. The current collector 15 may be an alloy foil of any of the above metals, or a foil formed by integrating multiple metal foils. When the current collector 15 is in the form of a foil, the thickness of the current collector 15 may be, for example, approximately 1 μm to 100 μm.

[0032] The positive electrode active material layer 16 is a layer containing a positive electrode active material capable of absorbing and releasing charge carriers such as lithium ions. Examples of the positive electrode active material include lithium composite metal oxides having a layered rock salt structure, metal oxides having a spinel structure, and polyanion compounds. The positive electrode active material layer 16 may contain a plurality of positive electrode active materials. In this embodiment, the positive electrode active material layer 16 is made of a composite oxide, olivine-type lithium iron phosphate (LiFePO ４ )

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

[0034] Each of the positive electrode active material layer 16 and the negative electrode active material layer 17 may further contain, as necessary, a conductive additive for improving electrical conductivity, a binder, an electrolyte (such as a polymer matrix, an ion-conductive polymer, or an electrolyte solution), an electrolyte supporting salt (lithium salt) for improving ionic conductivity, etc. The conductive additive is added to improve the conductivity of each electrode (bipolar electrode 11, positive terminal electrode 12, and negative terminal electrode 13). Examples of the conductive additive include acetylene black, carbon black, and graphite.

[0035] Examples of binders include fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluororubber; thermoplastic resins such as polypropylene and polyethylene; imide resins such as polyimide and polyamideimide; alkoxysilyl group-containing resins; acrylic resins such as acrylic acid and methacrylic acid; styrene-butadiene rubber (SBR); carboxymethyl cellulose; alginates such as sodium alginate and ammonium alginate; water-soluble cellulose ester crosslinked bodies; and starch-acrylic acid graft polymers. These binders can be used alone or in combination. Examples of solvents that can be used include water and N-methyl-2-pyrrolidone (NMP).

[0036] The sealing body 3 is formed in a frame shape on the peripheral portion of the electrode stack 2 so as to surround the electrode stack 2. The sealing body 3 is 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 3 forms an internal space S between each current collector 15 (between the electrodes) adjacent to each other in the first direction D1 and seals each of these internal spaces S. The above-mentioned electrolyte (electrolyte solution) is accommodated in each internal space S. The sealing body 3, together with the current collectors 15 adjacent to each other in the first direction D1, defines the internal space S that accommodates the electrolyte solution and prevents leakage of the electrolyte solution from the internal space S to the outside.

[0037] The sealing body 3 prevents moisture and the like from penetrating into the internal space S from the outside of the electrode stack 2. In this embodiment, the peripheral edge of the separator 14 is joined to the sealing body 3 while being embedded in the sealing body 3. The sealing body 3 is formed of, for example, an insulating resin material. Examples of the resin material include polypropylene, polyethylene, polystyrene, ABS resin, acid-modified polypropylene, acid-modified polyethylene, and acrylonitrile-styrene resin.

[0038] The main body 20 of the sealing body 3 includes a plurality of sealants 21, a plurality of spacers 22, and welded end portions 23. A sealant 21 is provided for each current collector 15. The sealant 21 has a rectangular frame shape and is provided on the peripheral portion 15c of the current collector 15. The sealant 21 covers the first surface 15a, the second surface 15b, and the end faces of the peripheral portion 15c of the current collector 15. The sealant 21 is welded to at least one of the first surface 15a and the second surface 15b of the current collector 15.

[0039] The spacers 22 are disposed between the sealing materials 21 adjacent to each other in the first direction D1. The spacers 22 maintain the space between the adjacent sealing materials 21, i.e., the space between the adjacent current collectors 15. The spacers 22 have a rectangular frame shape and are disposed on the peripheral edge portions 15c of the current collectors 15. The peripheral edge portions of the separators 14 are sandwiched between the sealing materials 21 and the spacers 22. The peripheral edge portions of the separators 14 are welded to at least one of the sealing materials 21 and the spacers 22.

[0040] In this embodiment, the edge of each spacer 22 on the internal space S side (i.e., inner edge 22 a) is located outside (on the opposite side to the internal space S) of the edge of each sealant 21 on the internal space S side (i.e., inner edge 21 a). When viewed from the first direction D1, a gap is formed between adjacent sealants 21 in the region between the inner edges 21 a and 22 a. On the other hand, in the region outside the inner edges 22 a, the spacers 22 are interposed between the adjacent sealants 21, so that the sealants 21 and the spacers 22 overlap each other.

[0041] The inner edge 22 a of the spacer 22 may be located closer to the internal space S (i.e., more inward) than the inner edge 21 a of the sealing material 21. In this case, the inner edge 22 a of the spacer 22 may be located more inward than the outer edge of the negative electrode active material layer 17. That is, the spacer 22 may include an overlapping portion that overlaps with the negative electrode active material layer 17 when viewed from the first direction D1. In this case, the spacer 22 may not be in contact with the current collector 15 (more specifically, the first surface 15 a of the current collector 15 on which the positive electrode active material layer 16 is provided) at the overlapping portion.

[0042] The welded end 23 has a rectangular frame shape surrounding the electrode stack 2 when viewed from the first direction D1. The welded end 23 is formed by integrating an edge of each sealant 21 opposite the internal space S with an edge of each spacer 22 opposite the internal space S through welding. In this embodiment, the welded end 23 is formed by welding together a portion of each sealant 21 located outside the outer periphery of the current collector 15 and a portion of each spacer 22 located outside the outer periphery of the current collector 15. In a region of the sealing body 3 where a communication hole 31 (described later) is not provided, an outer surface 23 s of the welded end 23 located opposite the internal space S extends along the first direction D1 and constitutes a side surface of the main body 20, i.e., a side surface of the sealing body 3.

[0043] The sealing body 3 has a first resin portion 24, a pair of second resin portions 25, and a frame portion 26 in a region where a communication hole 31 (described later) is provided. The first resin portion 24 extends along an outer surface 23s of the weld end portion 23 and is welded to the outer surface 23s. The outer surface 24s of the first resin portion 24 (the surface facing the opposite side from the outer surface 23s) constitutes the outer surface of the sealing body 3 in the region where the communication hole (described later) is provided. The pair of second resin portions 25 extend from each of both ends of the first resin portion 24 in the first direction D1 toward the interior (toward the internal space S as viewed from the first direction D1) from the weld end portion 23 to the sealing material 21. Each of the pair of second resin portions 25 is welded to the outer surfaces of the sealing materials 21 and the weld end portions 23 provided on the current collectors 15 of the positive and negative electrode terminal electrodes 12 and 13 in the first direction D1.

[0044] The frame portion 26 is provided on the outer surface 24s of the first resin portion 24. The frame portion 26 extends from the second resin portion 25 on the positive terminal electrode 12 side to the second resin portion 25 on the negative terminal electrode 13 side. Here, the outer edges of the frame portion 26 in the first direction D1 coincide with both ends of the second resin portion 25 in the first direction D1. The frame portion 26 may be formed separately from the first resin portion 24 and joined to the first resin portion 24, or may be formed integrally with the first resin portion 24. In the present embodiment, as an example, the first resin portion 24, the second resin portion 25, and the frame portion 26 are integrally formed with the main body 20 by injection molding. The frame portion 26 is sealed by a sealing film 30. The sealing film 30 is, for example, a laminate film.

[0045] The configuration of the sealing body 3 will be described in more detail below.

[0046] Fig. 3 is a schematic cross-sectional view showing the configuration around the communication hole in the sealing body. Fig. 4 is a side view of the sealing body from the outer surface (outer surface 24s) side on which the frame portion is provided. Fig. 5(a) is a schematic side view showing the positional relationship between the internal space and the communication hole, and Fig. 5(b) is a schematic side view showing the positional relationship between the frame portion and the communication hole. Fig. 5(b) corresponds to an enlarged view showing a part of Fig. 4. For convenience of explanation, Fig. 5(a) omits the frame portion 26 and the sealing film 30, and Figs. 4 and 5(b) omit the sealing film 30.

[0047] As shown in FIGS. 3 to 5 , the main body 20 and the first resin portion 24 of the sealing body 3 are formed with a plurality of communication holes 31 that communicate with each of the plurality of internal spaces S. Here, the communication holes 31 are provided in a wall portion 3A (see FIG. 1 ) of the frame-shaped sealing body 3 that is located on one side in the second direction D2. In other words, the region of the sealing body 3 where the communication holes 31 are provided is included in the wall portion 3A. The communication holes 31 are formed to penetrate the spacer 22 (and the welded end portion 23) and the first resin portion 24, for example, by cutting out a portion of the spacer 22 and removing a portion of the first resin portion 24 at a position corresponding to the cutout of the spacer 22. One opening 31A of the communication hole 31 is provided in the outer surface 24s of the first resin portion 24, and the other opening 31B is provided in the surface of the main body 20 that faces the internal space S.

[0048] As described above, in the energy storage module 1, a single internal space S is formed by a pair of adjacent current collectors 15 (electrodes). Therefore, the multiple internal spaces S are arranged along the first direction D1. In other words, the internal spaces S adjacent to each other along the first direction D1 share the current collectors 15 as a partition wall. Here, one communication hole 31 is provided for each internal space S so as to communicate with the corresponding internal space S. Furthermore, each of the multiple frame portions 26 protrudes from the outer surface 24s of the first resin portion 24 so as to surround the respective openings 31A of the multiple communication holes 31 as viewed from the second direction D2. Each of the multiple frame portions 26 is configured such that a predetermined number (here, three) of frames 26f surrounding a predetermined number (here, three) of the multiple openings 31A that overlap as viewed from the first direction D1 are integrated together as viewed from the second direction D2 while sharing the partition wall 26w. For each of the multiple internal spaces S, a test cell C is formed, through which a fluid F such as an electrolyte or gas flows (i.e., the cell is the subject of airtightness testing), by including one internal space S, one communication hole 31 communicating with the internal space S, and one frame 26f surrounding the opening 31A of the communication hole 31.

[0049] As an example, in the illustrated example, 30 test cells C are configured in the energy storage module 1, and the test cells C (internal spaces S) are numbered from 1 to 30 from one end to the other in the first direction D1. The openings 31A of the communication holes 31 corresponding to the first test cells C through the tenth test cells C are arranged in the third direction D3 with their positions in the first direction D1 slightly changed sequentially. Similarly, the openings 31A of the communication holes 31 corresponding to the eleventh test cells C through the twentieth test cells C are arranged in the third direction D3 with their positions in the first direction D1 slightly changed sequentially. Furthermore, the openings 31A of the communication holes 31 corresponding to the twenty-first test cells C through the thirtieth test cells C are arranged in the third direction D3 with their positions in the first direction D1 slightly changed sequentially.

[0050] In this embodiment, the positions of the openings 31A of the communication holes 31 corresponding to three test cells C with numbers (e.g., 1, 11, and 21) that differ by 10 are substantially the same in the third direction D3, and they are arranged along the first direction D1. Ten frame portions 26, each formed by integrating three frames 26f aligned in the first direction D1, are arranged along the third direction D3. Therefore, in this embodiment, ten rows of the frames 26f of three test cells C, each including one of the three internal spaces S arranged along the first direction D1, are arranged in the third direction D3 (see FIG. 9 for an example of the arrangement of the test cells C).

[0051] As an example, as shown in FIG. 5 , the multiple frame portions 26 may be configured to form at least two enclosed regions 33 having different lengths in the first direction D1, and may be asymmetric with respect to the first direction D1. Each enclosed region 33 is an area surrounded by a single frame 26f. In this example, each frame portion 26 forms three enclosed regions 33 (i.e., frames 26f). One of the three enclosed regions 33 (enclosed region 33A) has a longer length in the first direction D1 than the other two in the first direction D1. Note that FIG. 2 also schematically illustrates the relationship between the size of the frame portion 26 in the first direction D1 (size of frame 26f) and the size of the internal space S, which differs from the actual relationship. For example, unlike the description in FIG. 2 , the size of one frame 26f in the first direction D1 may be large enough to include multiple internal spaces S.

[0052] Next, an outline of a method for manufacturing the energy storage module used to manufacture the energy storage module 1 described above will be described.

[0053] This manufacturing method includes an injection step of pressing a fluid injection nozzle 43 (see FIGS. 6 and 7) against the periphery of the opening 31A of the communication hole 31 and injecting a fluid F into each of the plurality of internal spaces S via the communication hole 31. Specific examples of the injection step include a step of injecting an electrolyte solution into the internal space S and a step of inspecting the airtightness of the energy storage module 1 (steps S103 to S106 described below). In the step of injecting the electrolyte solution, the electrolyte solution, which is the fluid F, is injected into each internal space S via the frame 26f and the communication hole 31.

[0054] The process of conducting an airtightness test, which will be described in detail later, is carried out before the process of injecting the electrolyte. As an example of the airtightness test, a cell-to-external airtightness test is carried out. In this case, the fluid F is a test gas. In the cell-to-external airtightness test, a test gas such as helium is injected into the multiple internal spaces S through the communication holes 31, and a detection sensor disposed outside the energy storage module 1 detects whether or not the test gas is leaking. If the detection sensor does not detect the test gas, it is determined that there is no problem with the airtightness between the cell and the external space. In addition to helium, the test gas may be, for example, a rare gas such as argon, an inert gas such as nitrogen, or hydrogen, ammonia, or a halogen gas.

[0055] FIG. 6 is a schematic partial cross-sectional view showing an energy storage module manufacturing apparatus according to one embodiment. As shown in FIG. 6 , the injection step is performed using an energy storage module manufacturing apparatus 41. The energy storage module manufacturing apparatus 41 includes a decompression chamber 42, a fluid injection nozzle 43, a first restraining member 44, and a second restraining member 45. In the energy storage module 1, which is the workpiece in the injection step, the conductive member 18 and the sealing film 30, which are the components shown in FIG. 2 , are not provided, and the internal space S does not contain any electrolyte (hereinafter, the energy storage module 1 in this state may be referred to as the "module to be inspected 1A"). The conductive member 18 and the sealing film 30 are attached to the workpiece in a step subsequent to the injection step, and the energy storage module 1 shown in FIGS. 1 and 2 is obtained.

[0056] The decompression chamber 42 has a stage 46 and a chamber 47. The stage 46 has a mounting surface 46a on which the power storage module 1 is placed. A flat pallet 48, for example, is placed on the mounting surface 46a, and the power storage module 1 is placed on the pallet 48 (i.e., the power storage module 1 is placed via the pallet 48). The chamber 47 is formed in a box shape by four side walls 49 standing on the stage 46 and a roof 50 that closes the space defined by the stage 46 and the side walls 49.

[0057] In the chamber 47, one of the four side walls 49 is configured to be openable and closable. By opening this side wall 49, the energy storage module 1 placed on the pallet 48 can be inserted into and removed from the chamber 47. Of the four side walls 49, a pair of side walls 49, 49 that intersect with the side wall 49 on which the fluid injection nozzle 43 is provided, may be configured to be openable and closable. In this case, the energy storage module 1 placed on the pallet 48 can be introduced into the chamber 47 from one side of the pair of side walls 49, 49, and can be removed from the other side of the pair of side walls 49, 49 after the injection process has been performed. Therefore, the injection process can be performed while transporting a plurality of energy storage modules 1 in one direction, thereby improving the efficiency of the injection process.

[0058] The fluid injection nozzle 43 is provided on one side wall portion 49 of the chamber chamber 47 so as to be movable forward and backward relative to the mounting surface 46a. As shown in FIG. 7 , the fluid injection nozzle 43 has a nozzle head (attachment) 51 that ejects the fluid F. The nozzle head 51 has a head main body 52. ​​A packing 53 is provided on the head main body 52. ​​The head main body 52 and the packing 53 are disposed within the chamber chamber 47. The head main body 52 is provided with an outlet portion 54 that circulates and discharges the fluid F. The packing 53 is provided on a first side surface 52a, which is the tip surface of the head main body 52. ​​The packing 53 is provided with a flow path 55 that communicates with the outlet portion 54.

[0059] When the fluid F is injected from the fluid injection nozzle 43 into the internal space S, the fluid injection nozzle 43 advances toward the mounting surface 46a, and the packing 53 of the nozzle head 51 is pressed against the frame 26, thereby sealing the enclosed area 33 of the frame 26 from the outside. In this state, the fluid F is discharged from the flow path 55 of the nozzle head 51, and the fluid F is injected into each internal space S in the energy storage module 1 via the communication holes 31.

[0060] When injecting the fluid F, the nozzle head 51 is pressed against the frame 26, and then the chamber 47 is evacuated with the energy storage module 1 placed thereon, thereby reducing the pressure in each internal space S of the energy storage module 1. When injecting the electrolyte solution, the internal space S of the energy storage module 1 is reduced in pressure using the decompression chamber 42, thereby enabling the electrolyte solution to be efficiently injected via the communication holes 31.

[0061] When the internal space S is decompressed under atmospheric pressure, the internal space S is compressed by the atmospheric pressure, and the entrance to the internal space S (the portion connected to the communication hole 31) is blocked by the current collector 15 that constitutes the internal space S, which is thought to prevent the efficiency of electrolyte injection from improving. Therefore, by placing the electricity storage module 1 in a decompression chamber 42 and decompressing the outside of the electricity storage module 1, the pressure difference between the inside and outside of the internal space S is eliminated, and the efficiency of electrolyte injection can be sufficiently improved.

[0062] The same applies to the case where the test gas is injected, and by reducing the pressure in the internal space S of the energy storage module 1 using the decompression chamber 42, the test gas can be efficiently injected through the communication hole 31. Furthermore, by placing the energy storage module 1 inside the decompression chamber 42, the influence of the test gas contained in the atmosphere is suppressed, and the accuracy of the airtightness test can be improved.

[0063] The first restraining member 44 and the second restraining member 45 are members that restrain the energy storage module 1 at a constant pressure or at a constant size in order to protect the electrode stack 2 and the sealing body 3 from the load that occurs when the fluid F is injected. Examples of the load that occurs when the fluid F is injected include the pressing force that acts on the main body 20 of the sealing body 3 when the fluid injection nozzle 43 is pressed against the periphery of the opening 31A of the communication hole 31, the expansion force of the internal space S due to the injection of the fluid F, and the expansion force of the internal space S due to the pressure difference between the inside and outside of the internal space S when the module is placed in the decompression chamber 42.

[0064] It is desirable to apply an appropriate confining pressure to both the portion of the sealing body 3 against which the fluid injection nozzle 43 is pressed, and to the electrode stack 2 in which the internal space S is located. However, in the energy storage module 1, the dimensional tolerance in the thickness direction (first direction D1 / electrode stacking direction) may differ between the electrode stack 2 in which a plurality of electrodes are stacked, and the sealing body 3 that seals the internal space S formed between the electrodes of the electrode stack 2. Because the dimensional tolerance in the stacking direction during manufacturing differs between the electrode stack 2 and the sealing body 3, the dimensions in the stacking direction may differ between the electrode stack 2 and the sealing body 3 for each energy storage module 1 (work).

[0065] For example, it is considered that the dimensional tolerance in the stacking direction of the electrode stack 2, in which multiple electrodes are stacked, may be larger than the dimensional tolerance in the stacking direction of the sealing body 3. In some workpieces, the dimension in the stacking direction of the electrode stack 2 may be smaller than the dimension in the stacking direction of the sealing body 3. In this case, the end faces in the stacking direction of the electrode stack 2 (here, the surface of the positive terminal electrode 12 on which the positive electrode active material layer 16 is not provided, i.e., the first surface 15a of the current collector 15, and the surface of the negative terminal electrode 13 on which the negative electrode active material layer 17 is not provided, i.e., the second surface 15b of the current collector 15) become recessed with respect to the end faces in the stacking direction of the sealing body 3 (here, the outer surfaces in the first direction D1 of the sealant 21 provided on the current collectors 15 of the positive terminal electrode 12 and the negative terminal electrode 13).

[0066] Furthermore, in another workpiece, the dimension in the stacking direction of the electrode laminate 2 may be larger than the dimension in the stacking direction of the sealing body 3. In this case, the end faces in the stacking direction of the electrode laminate 2 (here, the face of the positive terminal electrode 12 on which the positive active material layer 16 is not provided, i.e., the first face 15a of the current collector 15, and the face of the negative terminal electrode 13 on which the negative active material layer 17 is not provided, i.e., the second face 15b of the current collector 15) will protrude relative to the end faces in the stacking direction of the sealing body 3 (here, the outer surfaces in the first direction D1 of the sealant 21 provided on the current collectors 15 of the positive terminal electrode 12 and the negative terminal electrode 13).

[0067] If the electrode stack 2 and sealing body 3 of such a workpiece are restrained with a uniform restraining force by a single restraining member, it is conceivable that the restraining pressure will be insufficient for either the portion of the sealing body 3 against which the fluid injection nozzle 43 is pressed, or the electrode stack 2 in which the internal space S is located. In contrast, the energy storage module manufacturing apparatus 41 has the first restraining member 44 and the second restraining member 45 that are provided independently of each other, so that even if the dimensions of the electrode stack 2 in the stacking direction and the dimensions of the sealing body 3 in the stacking direction vary for each energy storage module 1, it is possible to apply an appropriate restraining pressure to both the portion of the sealing body 3 against which the fluid injection nozzle 43 is pressed, and the electrode stack 2 in which the internal space S is located.

[0068] Note that, by separating the first restraining member 44 and the second restraining member 45, it is possible to restrain the energy storage module 1 so that the load generated when injecting the fluid F is not applied thereto, but the first restraining member 44 and the second restraining member 45 may be integrated as long as it is possible to prevent the load from being applied to the energy storage module 1. Furthermore, the first restraining member 44 and the second restraining member 45 may each be further separated.

[0069] As shown in FIG. 6 , the first restraint member 44 includes cylinders 61A and 61B that are extendable and retractable in the first direction D1 and restraint plates 62A and 62B attached to the ends of the cylinders 61A and 61B. In this embodiment, a pair of first restraint members 44A and 44B is used as the first restraint member 44. The first restraint member 44A includes a cylinder 61A and a restraint plate 62A, and the first restraint member 44B includes a cylinder 61B and a restraint plate 62B. The first restraint member 44A is provided on the stage 46 of the decompression chamber 42 so as to be able to move back and forth in the first direction D1. The first restraint member 44B is provided on the roof portion 50 of the chamber 47 so as to face the first restraint member 44A and be able to move back and forth in the first direction D1.

[0070] Both constraining plates 62A and 62B are disposed within chamber 47. Constraining plates 62A and 62B have, for example, the same planar shape. Cylinder 61A of first constraining member 44A and cylinder 61B of first constraining member 44B cooperate to sandwich power storage module 1, which is the workpiece, between constraining plates 62A and 62B, thereby applying constraining pressure to a predetermined region of power storage module 1.

[0071] The first restraining member 44 restrains a first region of the sealing body 3, in which the plurality of communication holes 31 are provided, with a first restraining pressure P1. In the present embodiment, the first restraining pressure P1 by the first restraining member 44 is applied to the first region in the stacking direction (first direction D1). The first region is a region where the sealing material 21 and the spacer 22 overlap in the stacking direction. In the present embodiment, when the energy storage module 1 is viewed from the stacking direction, the first region F1 is a rectangular (here, oblong) region that corresponds to the wall portion 3A of the sealing body 3, in which the plurality of communication holes 31 are provided.

[0072] The second restraint member 45 includes a plurality of cylinders 63 that are extendable and retractable in the first direction D1 and restraint plates 64 attached to the tips of the cylinders 63. The second restraint member 45 is provided on the roof 50 of the chamber 47 so as to face the mounting surface 46a of the stage 46 and be movable back and forth in the first direction D1. As shown in the illustrated example, another restraint plate 65 may be provided between the restraint plate 64 and the energy storage module 1. The restraint plate 65 may be made of, for example, a stainless steel plate as a replaceable consumable item. The restraint plate 64 is arranged horizontally alongside the restraint plate 62B within the chamber 47. When the cylinders 63 are driven, the energy storage module 1 (the workpiece) is sandwiched between the restraint plates 64, 65, the stage 46, and the pallet 48, thereby applying restraint pressure to a predetermined region of the energy storage module 1.

[0073] Next, the method for manufacturing the energy storage module according to this embodiment will be described in detail.

[0074] 8 is a flowchart showing a step of the energy storage module manufacturing method according to this embodiment. In this manufacturing method, first, as shown in FIG. 6, a step of moving and arranging the inspection target module 1A in the decompression chamber 42 (chamber) (step S101, arrangement step) and a step of attaching the fluid injection nozzle 43 to the inspection target module 1A (step S102) are carried out in this order.

[0075] Next, a cell-to-external vacuum test (external cell vacuum test) is performed (step S103, second test step). In step S103, evacuation of the decompression chamber 42 (chamber chamber 47) is started, thereby reducing the pressure inside the decompression chamber 42. Meanwhile, in step S103, a pressure gauge is installed in each of the test cells C, and each of the test cells C is sealed. Then, in step S103, the pressure gauge is used to measure the pressure change in each of the test cells C.

[0076] As a result of the inspection in step S103, if the air pressure inside the decompression chamber 42 is equal to or lower than a predetermined value (extra-cell inspection vacuum threshold) and the pressure change in each of the inspected cells C is equal to or lower than another predetermined value, the extra-cell vacuum inspection is judged to be OK. As an example, in step S103, if the air pressure inside the decompression chamber 42 is equal to or lower than 500 Pa and the pressure change in each of the inspected cells C is equal to or higher than 10 kPa, the inspection is judged to be OK.

[0077] Next, if the measurement result in step S103 indicates that the extra-cell vacuum test is OK, a vacuum test (intra-cell vacuum test) is performed on each individual test cell C (step S104, first test step, vacuum test step). Step S104 will be described in more detail.

[0078] First, as shown in FIG. 9 , it is assumed that each of the test cells C is assigned a number. This point will be explained in detail. As described above, the multiple internal spaces S are arranged along the first direction D1. Numbers from 1 to 30 are assigned in order from the internal space S located at one end of the first direction D1 to the internal space S located at the other end of the first direction D1, and these numbers are used in common with the numbers of the test cells C including each internal space S and the numbers of the communication holes 31 communicating with each internal space S. That is, for example, the number of the test cell C including a certain Nth internal space S and the number of the communication hole 31 communicating with the Nth internal space S are similarly numbered N.

[0079] At this time, as described above, the openings 31A of the first through tenth communication holes 31 are arranged in a row in the third direction D3, and above them (on one side in the first direction D1) the openings 31A of the eleventh through twentieth communication holes 31 are arranged in a row in the third direction, and above them (on one side in the first direction D1) the openings 31A of the eleventh through twentieth communication holes 31 are arranged in a row in the third direction, and above them the openings 31A of the twenty-first through thirtieth communication holes 31 are arranged in a row in the third direction. Therefore, the openings 31A of a predetermined number (here, three) of communication holes 31 whose numbers are separated by the number of arrangements of the openings 31A in the third direction D3 (here, 10), such as the first, eleventh, and 21st communication holes 31, overlap when viewed from the first direction D1.

[0080] 9 and 10, the arrangement of the openings 31A of the communication holes 31 in the first direction D1 and the third direction D3 is indicated by numbers. Since the numbers of the communication holes 31 are the same as the numbers of the test cells C, the reference numerals of the test cells C are assigned to each number in FIGS. 9 and 10. A predetermined number (three in this case) of frames 26f surrounding a predetermined number (three in this case) of overlapping openings 31A as viewed from the first direction D1 among the multiple openings 31A are integrally configured while sharing partition walls 26w, and are arranged in the first direction D1.

[0081] As a result, at least two adjacent states are created between the multiple test cells C. That is, in the first state, the internal spaces S of two test cells C are adjacent to each other in the first direction D1, with the current collector 15 serving as a partition wall. That is, when one test cell C is defined as the first cell A1, a first adjacent cell N1 is created, which is a test cell C including an internal space S adjacent to the internal space S included in the first cell A1 in the first direction D1 via the current collector 15. As an example, when the third test cell C is defined as the first cell A1, the second test cell C and the fourth test cell C are the first adjacent cells N1.

[0082] On the other hand, the second mode is a mode in which the frames 26f surrounding the openings 31A of the communication holes 31 between two test cells C are adjacent to each other in the first direction D1 while sharing the partition wall 26w. That is, when one test cell C is defined as the first cell A1, a second adjacent cell N2 is generated, which is a test cell C including a frame 26f adjacent to the first direction D1 while sharing the partition wall 26w with the frame 26f included in the first cell A1. As an example, when the third test cell C is defined as the first cell A1, the thirteenth test cell C is the second adjacent cell N2. In this case, since the frame 26f of the first cell A1 is located in the bottom row of the three rows in the first direction D1, there is one second adjacent cell N2. However, if the frame 26f of the first cell A1 is located in the center row (for example, if the 14th inspected cell C is the first cell A1), there will be two second adjacent cells N2, one above and one below (for example, the 4th and 24th inspected cells C will be the second adjacent cells N2).

[0083] Between the first cell A1 and the first adjacent cell N1 (i.e., the first aspect), the internal space S is adjacent via the current collector 15, so it is desirable to inspect the airtightness depending on whether or not there are defects in the current collector 15, etc. that separates the internal space S (for example, the current collector 15 itself, the welded area between the sealing material 21 and the current collector 15, or the welded end 23 integrated with the sealing material 21).

[0084] On the other hand, between the first cell A1 and the second adjacent cell N2 (i.e., the second aspect), because the frame 26f is adjacent to the partition wall 26w interposed therebetween, it is desirable to inspect the airtightness depending on the presence or absence of defects in the partition wall 26w, etc. (for example, the partition wall 26w itself, the first resin part 24 integrated with the partition wall 26w, the second resin part 25 integrated with the first resin part 24, and further, the area between the first resin part 24 and the welded end part 23). Therefore, in step S104, the airtightness between the first cell A1 and the first adjacent cell N1 and the airtightness between the first cell A1 and the second adjacent cell N2 are both inspected simultaneously.

[0085] To this end, in step S104, a first adjacent cell N1 (for example, the second and fourth inspected cells C) including an internal space S adjacent to a first cell A1 (for example, the third inspected cell C) among the plurality of inspected cells C and sharing the current collector 15 with the internal space S and adjacent to the first direction D1, and a second adjacent cell N2 (for example, the thirteenth inspected cell C) including a frame 26 f adjacent to the frame 26 f of the first cell A1 among the plurality of inspected cells C and sharing the partition wall 26 w with the frame 26 f of the first cell A1 among the plurality of inspected cells C are evacuated, and the presence or absence of a pressure change in the first cell A1 is measured. This makes it possible to inspect the airtightness between the first cell A1 and the first adjacent cell N1, whose internal spaces S are adjacent to each other via the current collector 15 (cell-to-cell inspection), and simultaneously inspect the airtightness between the first cell A1 and the second adjacent cell N2, whose frames 26 f are adjacent to each other via the partition wall 26 w (frame-to-frame inspection). In this way, in step S104, a first airtightness test, which is an airtightness test between the first cell A1 and the first adjacent cell N1, and a second airtightness test, which is an airtightness test between the first cell A1 and the second adjacent cell N2, are performed simultaneously.

[0086] In this embodiment, in step S104, the above-described inspection is performed on all test cells C simultaneously. That is, in the example of FIG. 9A , test cells C Nos. 2, 4, 6, 8, 10, 13, 15, 17, 19, 22, 24, 26, 28, and 30 are evacuated, and pressure gauges are installed in the remaining test cells C (first cells A1), i.e., Nos. 1, 3, 5, 7, 9, 11, 12, 14, 16, 18, 20, 21, 23, 25, 27, and 29, to measure pressure changes. An attachment corresponding to each test cell C and a pipe corresponding to each communication hole 31 are provided, and the pipes extend to the outside of the decompression chamber 42. A vacuum pump and a pressure gauge may be installed for each pipe, or multiple pipes may be installed together. That is, step S104 is performed in a state where an attachment is attached to the frame 26f of each test cell C.

[0087] However, when inspecting all the cells at once in this manner, inspection cannot be performed between some of the inspected cells C due to the arrangement order of the inspected cells C. In the illustrated example, the communication holes 31 of the inspected cells C numbered 1, 11, and 21 are aligned in the first direction D1 via the common frame 26f, and none of them are evacuated, so inspection between the frames between them is not possible. Furthermore, the internal spaces S of the inspected cells C numbered 11 and 12 are aligned in the first direction D1 via the common current collector 15, and none of them are evacuated, so inspection between the cells between them is not possible.

[0088] 9B, the cells C to be inspected (C) Nos. 2, 4, 6, 8, 10, 11, 13, 15, 17, 19, 20, 22, 24, 26, 28, and 30 are evacuated, and pressure gauges are installed in the remaining cells C (first cells A1), i.e., Nos. 1, 3, 5, 7, 9, 12, 14, 16, 18, 21, 23, 25, 27, and 29, to measure pressure changes.

[0089] This makes it possible to obtain frame-to-frame results between test cells C Nos. 1, 11, and 21, for which frame-to-frame inspection was not possible in the first inspection, and also makes it possible to perform cell-to-cell inspection between test cells C Nos. 11, 12, 20, and 21, for which cell-to-cell inspection was not possible in the first inspection. Note that, although the above example describes a case where inspection is performed on all test cells C at once, it is also possible to divide all test cells C into a plurality of groups, each including the first cell A1, the first adjacent cell N1, and the second adjacent cell N2, and perform step S104 for each group.

[0090] As a result of the inspection in step S104, if the pressure change in the first cell A1 that has not been evacuated is equal to or less than a predetermined value (for example, 10 kPa), the result is judged to be OK.

[0091] Next, the vacuum pumping in the decompression chamber 42 continues, and with the air pressure reduced to a certain level, a gas test (intra-cell gas test) is performed on each individual test cell C (step S105, first test step, gas test step). Step S105 will be described in more detail. The intra-cell gas test in step S105 is performed on the test module 1A that was judged OK in step S104 (excluding the first cell A1 that was judged NG). Step S105 uses gas (test gas). This makes it possible to detect smaller defects than step S104. In step S105, similar to step S104, a first airtightness test, which is an airtightness test between the first cell A1 and the first adjacent cell N1, and a second airtightness test, which is an airtightness test between the first cell A1 and the second adjacent cell N2, are simultaneously performed.

[0092] For this purpose, in step S105, if the pressure change in the first cell A1 is equal to or less than a predetermined value (OK judgment), a gas (a test gas, for example, helium) is applied to the first cell A1 (for example, the third cell C) among the multiple cells C to be inspected, and leak detectors are installed in the first adjacent cell N1 (for example, the second and fourth cells C to be inspected) and the second adjacent cell N2 (for example, the thirteenth cell C to be inspected) to measure the amount of gas leaking from the first cell A1. In this embodiment, a helium leak detector is used as the leak detector, and the amount of helium gas leaking (Pa·m ３ / s) is measured (to measure the presence or absence of leaking gas). However, a flow meter may be installed in place of the leak detector in the first adjacent cell N1 and the second adjacent cell N2. In this case, the flow meter measures the flow rate (m ３ / s) is measured.

[0093] As a result, in step S105, similar to step S104, it is possible to inspect the airtightness between the first cell A1 and the first adjacent cell N1, whose internal spaces S are adjacent to each other via the current collector 15 (cell-to-cell inspection), and simultaneously inspect the airtightness between the first cell A1 and the second adjacent cell N2, whose frames 26f are adjacent to each other via the partition wall 26w (frame-to-frame inspection). Also, in step S105, similar to step S104, it is possible to inspect the presence or absence of similar defects in the cell-to-cell inspection and frame-to-frame inspection. However, the cell-to-cell inspection and frame-to-frame inspection may be performed separately. That is, in step S105, gas may be applied to the first cell A1, and the amount of gas leakage (presence or absence of leaking gas) from at least one of the first adjacent cell N1 and the second adjacent cell N2 may be measured.

[0094] In this embodiment, the above-described inspection is performed simultaneously on all test cells C. That is, in the example of FIG. 10A , gas is applied to test cells C (first cells A1) Nos. 1, 3, 5, 7, 9, 12, 14, 16, 18, 20, 23, 25, 27, and 29, and leak detectors are installed in the remaining test cells C, i.e., Nos. 2, 4, 6, 8, 10, 11, 13, 15, 17, 19, 21, 22, 24, 26, 28, and 30, to measure the amount of gas leaking from the first cells A1. An attachment corresponding to each test cell C and piping corresponding to each communication hole 31 are provided, and the piping extends to the outside of the decompression chamber 42. The gas application means (for example, the nozzle head 51) and the leak detector may be provided for each pipe, or multiple pipes may be installed together. That is, step S105 is performed with the attachment attached to the frame 26f of each test cell C.

[0095] However, when inspecting all the cells at once in this manner, as in the case of the intra-cell vacuum inspection described above, inspection cannot be performed between some of the inspected cells C due to the arrangement order of the inspected cells C. In the illustrated example, the communication holes 31 of the inspected cells C Nos. 11 and 21 are aligned in the first direction D1 via the common frame 26f, and no gas is applied to any of them, so frame-to-frame inspection cannot be performed between them. Furthermore, the internal spaces S of the inspected cells C Nos. 10, 11, 21, and 22 are aligned in the first direction D1 via the common current collector 15, and no gas is applied to any of them, so cell-to-cell inspection cannot be performed between them.

[0096] Therefore, in step S105, in order to further inspect the test cells C for which the cell-to-cell and frame-to-frame inspections could not be performed, the test is performed again using a different combination of numbers. As an example, in the example of FIG. 10B, gas is applied to test cells C (first cells A1) Nos. 1, 3, 5, 7, 9, 10, 12, 14, 16, 18, 20, 21, 23, 25, 27, and 29, and leak detectors are installed in the other test cells C, i.e., Nos. 2, 4, 6, 8, 11, 13, 15, 17, 19, 22, 24, 26, 28, and 30, to measure the amount of gas leaking from the first cells A1. An attachment corresponding to each test cell C and a pipe corresponding to each communication hole 31 are provided, and the pipes extend to the outside of the decompression chamber 42. A gas application means (e.g., a nozzle head 51) and a leak detector may be provided for each pipe, or multiple pipes may be installed together.

[0097] This makes it possible to obtain frame-to-frame results between the 11th and 21st test cells C, for which frame-to-frame inspection was not possible in the first test, and also makes it possible to perform cell-to-cell inspection between the 10th, 11th, 21st, and 22nd test cells C, for which frame-to-cell inspection was not possible in the first test. Note that, although the above example describes a case where inspection is performed on all test cells C at once, it is also possible to divide all test cells C into a plurality of groups, each including the first cell A1, the first adjacent cell N1, and the second adjacent cell N2, and perform step S105 for each group.

[0098] As a result of the inspection in step S105, it is determined that the applied gas pressure of the first cell A1 is equal to or greater than a predetermined value (for example, 9.5 kPa in gauge pressure), and the gas leakage rate (helium leakage rate) of the first adjacent cell N1 and the second adjacent cell N2 is equal to or greater than a predetermined value (for example, the standard value Pa m ３ / s), it is judged as OK. In step S105, gas leak rate logging is started, and when the applied gas pressure of the first cell A1 exceeds a certain upper limit (for example, 1000 Pa in gauge pressure), and when the gas leak amount of the first adjacent cell N1 or the second adjacent cell N2 exceeds a certain upper limit (for example, 1.0 × 10 －３ P.A.M. ３ / s), the test may be stopped.

[0099] In the next step, a cell-to-external gas test (external cell gas test) is performed (step S106, third test step). In this embodiment, in step S106, gas is applied to all of the test cells C while the decompression chamber 42 is evacuated, and a leak detector is installed in the decompression chamber 42 to measure the amount of gas leaked into the decompression chamber 42. However, in step S106, it is sufficient that a cell-to-external gas test is possible, and therefore it is sufficient that a pressure difference exists between the decompression chamber 42 and the test cells C. Therefore, a process may be performed, such as introducing gas into the decompression chamber 42 so that the gauge pressure of the decompression chamber 42 is higher than the gauge pressure of the test cells C. In this case, leak detectors may be installed in all of the test cells C instead of the decompression chamber 42. As described above, in step S106, the amount of gas leaked due to the pressure difference between all of the test cells C and the decompression chamber 42 is measured.

[0100] Thereafter, the inside of the decompression chamber 42 is opened to the atmosphere (S107), and the series of inspections is completed.

[0101] Note that step S106 may be performed before at least one of step S104 and step S105. That is, step S106 may be performed after step S104 and before step S105, or may be performed before step S104.

[0102] In the above example, steps S104 and S105 are performed multiple times (twice in the above example) because some of the test cells C cannot be inspected in one go due to the arrangement of the test cells C. However, depending on the arrangement of the test cells C, steps S104 and S105 may not need to be performed multiple times.

[0103] As described above, in the energy storage module manufacturing method according to this embodiment, the first inspection step (steps S104 and S105) is performed with the module to be inspected 1A, which is the energy storage module 1 before the electrolyte is poured, placed in the decompression chamber 42. The module to be inspected 1A (energy storage module 1) has an electrode stack 2 including a plurality of electrodes stacked along the first direction D1, and a sealing body 3 that is provided on the electrode stack 2 so as to surround the electrode stack 2 and that seals a plurality of internal spaces S formed between electrodes adjacent in the first direction D1.

[0104] The sealing body 3 is formed with a plurality of communication holes 31 that communicate with each of the internal spaces S, and a plurality of frame portions 26 are integrally formed on an outer surface 24s of the sealing body 3 where the communication holes 31 open. Each of the plurality of frame portions 26 is formed by a predetermined number (e.g., three) of frames 26f that are integrated together and share a partition wall 26w in the first direction D1. Each of the predetermined number of frames 26f surrounds a predetermined number (e.g., three) of openings 31A of the communication holes 31 on the outer surface 23s of the sealing body 3 that overlap when viewed from the first direction D1. For each of the plurality of internal spaces S, one internal space S, one communication hole 31 that communicates with the internal space S, and one frame 26f surrounding the opening 31A of the communication hole 31 constitute one test cell C through which the fluid F flows.

[0105] In the inspected module 1A configured in this manner, it is necessary to inspect the airtightness between the internal spaces S adjacent in the first direction D1 via the current collector 15 (i.e., the airtightness of the current collector 15, the sealant 21, the welded end portion 23, etc.), and the airtightness between the frames 26f adjacent in the first direction D1 via the partition wall 26w (i.e., the airtightness of the partition wall 26w, the first resin portion 24, etc.). Therefore, in the energy storage module manufacturing method according to the present embodiment, in the first inspection step, a first airtight inspection is performed simultaneously, which is an airtight inspection between a first cell A1 of the multiple inspected cells C and a first adjacent cell N1 including an internal space S adjacent in the first direction D1 to the internal space S of the first cell A1 via the current collector 15, and a second airtight inspection is performed simultaneously between the first cell A1 of the multiple inspected cells C and a second adjacent cell N2 including a frame 26f adjacent in the first direction D1 to the frame 26f of the first cell A1 via the partition wall 26w.

[0106] In this way, the energy storage module manufacturing method according to this embodiment is efficient because it simultaneously inspects the airtightness between the internal spaces S adjacent to each other in the first direction D1 and the airtightness between the frames 26f adjacent to each other in the first direction D1. Therefore, the energy storage module manufacturing method according to this embodiment improves productivity.

[0107] Furthermore, in the energy storage module manufacturing method according to this embodiment, the first inspection step includes a gas inspection step (step S105) in which a first airtightness inspection and a second airtightness inspection are simultaneously performed by applying gas to the first cell A1 and measuring the presence or absence of gas leaking into the first adjacent cell N1 and the second adjacent cell N2. In this way, by performing the airtightness inspection by applying gas to the first cell A1, it is possible to reliably inspect the airtightness between the first cell A1 and the first adjacent cell N1 and the second adjacent cell N2.

[0108] Furthermore, in the energy storage module manufacturing method according to this embodiment, the first inspection step includes a vacuum inspection step (step S104) before the gas inspection step (step S105), in which the first adjacent cell N1 and the second adjacent cell N2 are evacuated and a pressure change in the first cell A1 is measured, thereby simultaneously performing a first airtightness inspection and a second airtightness inspection. By further performing an airtightness inspection by evacuating the first adjacent cell N1 and the second adjacent cell N2 in this manner, it is possible to more reliably inspect the airtightness between the first cell A1 and the first adjacent cell N1 and the second adjacent cell N2. In particular, the gas inspection step can be performed on the inspected cell C, which has already achieved a certain level of airtightness in the vacuum inspection step. Therefore, it is possible to perform further airtightness inspections while avoiding large amounts of gas leaking from the inspected cell C.

[0109] Furthermore, in the energy storage module manufacturing method according to this embodiment, the multiple test cells C may be divided into multiple groups each including the first cell A1, the first adjacent cell N1, and the second adjacent cell N2, and the gas testing process may be performed for each group. In this case, the multiple test cells C are tested simultaneously, which is efficient. Therefore, in this case, productivity is further improved.

[0110] Furthermore, in the energy storage module manufacturing method according to this embodiment, the multiple test cells C may be divided into multiple groups each including the first cell A1, the first adjacent cell N1, and the second adjacent cell N2, and the vacuum testing process may be performed for each group. In this case, the number of leak detectors can be reduced. Tests of multiple test cells C are performed simultaneously, which is efficient. Therefore, in this case, productivity is further improved.

[0111] Furthermore, the energy storage module manufacturing method according to this embodiment includes a second inspection step (step S103) that occurs after the placement step (step S101) and before the first inspection step, in which the inside of the decompression chamber 42 is evacuated and the presence or absence of a change in pressure is measured for all of the inspected cells C. Therefore, if there is a major defect in the inspected module 1A, by performing an overall airtightness inspection in this manner prior to the airtightness inspection of the individual inspected cells C, it becomes possible to quickly discover inspected modules 1A that are judged to be NG, thereby further improving productivity.

[0112] Furthermore, the energy storage module manufacturing method according to this embodiment includes a third inspection step (step S106) after the first inspection step, in which the amount of gas leakage due to the differential pressure between all of the test cells C and the decompression chamber 42 is measured. This makes it possible to perform an airtight inspection between the test module 1A and the outside of the test module 1A, enabling a more reliable airtight inspection of the test module 1A. This further improves productivity.

[0113] The above embodiment has been described as an example of the method for manufacturing an electric storage module according to the present invention. Therefore, the method for manufacturing an electric storage module according to the present invention is not limited to the above embodiment and can be modified.

[0114] For example, in the above embodiment, in the vacuum inspection step (step S104) of the first inspection process, an example was given in which two inspections were performed using different test cells C for evacuation and pressure measurement. However, depending on the arrangement order of the test cells C, the second inspection may not be necessary in the vacuum inspection step. The same applies to the gas inspection step (step S105) of the first inspection process.

[0115] In the above embodiment, the second inspection process (step S103) was performed before the vacuum inspection process (step S104) of the first inspection process, and the third inspection process (step S106) was performed after the gas inspection process (step S105) of the first inspection process. The vacuum inspection process and gas inspection process of the first inspection process are airtight inspections between the inspected cells C, and the third inspection process and fourth inspection process are airtight inspections between the inspected module 1A and the outside. Therefore, the order of the first inspection process, second inspection process, and third inspection process is not limited to this and may be changed as desired. Furthermore, in the first inspection process, it is sufficient to perform an airtight inspection between the inspected cells C, and one of the vacuum inspection process and the gas inspection process may be omitted. Furthermore, the second inspection process may be omitted by performing an airtight inspection between the inspected module 1A and the outside in the third inspection process.

[0116] 11 is a flowchart showing one step of a method for manufacturing an energy storage module according to a modified example. Next, the method for manufacturing an energy storage module according to the modified example will be described. First, steps S101 and S102 are performed, as in the above embodiment. Next, as in the above embodiment, evacuation of the decompression chamber 42 (chamber chamber 47) is started, and pressure changes in the test cells C are measured using pressure gauges installed in the test cells C, thereby performing step S103.

[0117] Next, as in the above embodiment, the decompression chamber 42 is evacuated and gas is applied to all the test cells C, and a leak detector is installed in the decompression chamber 42 to measure the amount of gas leaked into the decompression chamber 42, thereby performing the above step S106. That is, here, the amount of gas leaked due to the pressure difference between all the test cells C and the inside of the decompression chamber 42 is measured.

[0118] Next, with pressure gauges installed in the first adjacent cell N1 and the second adjacent cell N2, gas (a test gas, e.g., helium) is applied to the first cell A1 while measuring the presence or absence of a pressure change in at least one of the first adjacent cell N1 and the second adjacent cell N2 (step S108). As an example, in step S108, by applying gas to the first cell A1 and measuring the presence or absence of a pressure change in the first adjacent cell N1 and the second adjacent cell N2, a first airtightness test between the first cell A1 and the first adjacent cell N1 and a second airtightness test between the first cell A1 and the second adjacent cell N2 can be simultaneously performed. In step S108, pressure changes due to gas leaking from the first cell A1 to the first adjacent cell N1 or the second adjacent cell N2 are confirmed. That is, in step S108, based on the differential pressure between the cells due to the application of gas, a first airtightness test, which is an airtightness test between the first cell A1 and the first adjacent cell N1, and a second airtightness test, which is an airtightness test between the first cell A1 and the second adjacent cell N2, can be performed simultaneously.

[0119] Then, as in the above embodiment, the inside of the decompression chamber 42 is opened to the atmosphere (S107), completing the series of inspections. In this way, the energy storage module manufacturing method according to the modified example makes it possible to perform various airtightness inspections without installing gas leak detectors on the multiple inspected cells C. However, even when step S107 is performed as in this modified example, at least one of steps S104 and S105 may also be performed, as in the above embodiment.

[0120] The following additional notes will be made regarding the above embodiment.

[0121] a plurality of communication holes communicating with each of the plurality of internal spaces and having openings on the outer surface of the sealing body; and a plurality of frame portions integrally formed on the outer surface having the openings, the plurality of frame portions each having a predetermined number of openings overlapping each other when viewed from the first direction, the plurality of openings being formed in the plurality of spaces; and a plurality of frame portions each having a predetermined number of openings overlapping each other when viewed from the first direction. the predetermined number of frames surrounding each opening are integrated while sharing a partition wall in the first direction, and an inspected cell is formed for each of the plurality of internal spaces, the inspected cell including one internal space, one communication hole communicating with the internal space, and one frame surrounding the opening of the communication hole, and the plurality of inspected cells include a first cell that is one of the inspected cells, a first adjacent cell that is the inspected cell including the internal space included in the first cell and adjacent to the internal space in the first direction, and a second adjacent cell that is the inspected cell including the frame included in the first cell and adjacent to the frame, sharing the partition wall; and in the first inspection step, with an attachment attached to the frame included in the first cell, a first airtightness inspection that is an airtightness inspection between the first cell and the first adjacent cell and a second airtightness inspection that is an airtightness inspection between the first cell and the second adjacent cell are simultaneously performed.

[0122] The energy storage module manufacturing method may be [2] "the energy storage module manufacturing method described in the above [1], wherein the first inspection process includes a process of applying gas to the first cell and measuring whether or not there is a pressure change in at least one of the first adjacent cell and the second adjacent cell."

[0123] The energy storage module manufacturing method may be [3] "the energy storage module manufacturing method described in the above [1] or [2], wherein the first inspection process includes a gas inspection process in which the first airtightness inspection and the second airtightness inspection are performed simultaneously by applying gas to the first cell and measuring the presence or absence of the gas leaking to the first adjacent cell and the second adjacent cell."

[0124] The energy storage module manufacturing method may be [4] "the energy storage module manufacturing method described in any one of the above [1] to [3], wherein the first inspection process includes a vacuum inspection process in which the first airtightness inspection and the second airtightness inspection are performed simultaneously by evacuating the first adjacent cell and the second adjacent cell and measuring whether or not there is a change in pressure in the first cell."

[0125] The energy storage module manufacturing method may be [5] "the energy storage module manufacturing method described in the above [3], in which a plurality of the inspected cells are divided into a plurality of groups including the first cell, the first adjacent cell, and the second adjacent cell, and the gas inspection process is performed for each of the groups."

[0126] The energy storage module manufacturing method may be [6] "the energy storage module manufacturing method described in [4] above, in which a plurality of the inspected cells are divided into a plurality of groups including the first cell, the first adjacent cell, and the second adjacent cell, and the vacuum inspection process is performed for each of the groups."

[0127] The energy storage module manufacturing method may be [7] "the energy storage module manufacturing method according to any one of the above [1] to [6], which includes a second inspection step of evacuating the chamber after the placement step and before the first inspection step, and measuring whether or not there is a change in pressure in all of the inspected cells."

[0128] The energy storage module manufacturing method may be [8] "the energy storage module manufacturing method described in any one of [1] to [7] above, including a third inspection process of measuring the amount of gas leakage due to the pressure difference between all the inspected cells and the chamber after the first inspection process."

[0129] 1...storage module, 1A...module to be inspected, 2...electrode stack, 3...sealing body, 23s...outer surface, 26...frame portion, 26f...frame, 31...communicating hole, 31A...opening, 42...decompression chamber (chamber), A1...first cell, C...cell to be inspected, N1...first adjacent cell, N2...second adjacent cell, S...internal space.

Claims

1. An electrode stack comprising a plurality of electrodes stacked along a first direction, A sealing body provided on the electrode stack so as to surround the electrode stack, for sealing a plurality of internal spaces formed between adjacent electrodes in the first direction, The electrolyte contained in the aforementioned internal space, A method for manufacturing an energy storage module comprising: A placement step of placing the module to be inspected, which is the energy storage module, inside the chamber before the electrolyte is contained therein, Following the arrangement step, a first inspection step is performed in which the module to be inspected is inspected within the chamber, Equipped with, The aforementioned encapsulant is The outer surface facing the opposite side of the aforementioned interior space, Multiple communication holes that communicate with each of the multiple internal spaces and have openings on the outer surface of the sealing body, A plurality of frame portions integrally provided on the outer surface having the opening, It has, Each of the multiple frame sections is constructed by integrating a predetermined number of frames that surround each of the predetermined number of openings that overlap when viewed from the first direction, while sharing a partition wall in the first direction. For each of the multiple internal spaces, a cell to be inspected is formed, which includes one internal space, one communication hole communicating with the internal space, and one frame surrounding the opening of the communication hole. Multiple of the cells to be inspected are, A first cell which is the cell to be inspected, The first cell includes an internal space adjacent to the first cell in the first direction, which is the cell under inspection. The second adjacent cell, which is the cell under inspection, includes the frame and partition wall shared with the first cell, Includes, In the first inspection step, with the attachment mounted on the frame contained in the first cell, a first airtightness test, which is an airtightness test between the first cell and the first adjacent cell, and a second airtightness test, which is an airtightness test between the first cell and the second adjacent cell are performed simultaneously. Method for manufacturing energy storage modules.

2. The first inspection step includes applying gas to the first cell and measuring whether or not there is a pressure change in at least one of the first adjacent cell and the second adjacent cell. A method for manufacturing an energy storage module according to claim 1.

3. The first inspection step includes a gas inspection step that simultaneously performs a first airtightness test and a second airtightness test by applying gas to the first cell and measuring the presence or absence of the gas leaking to the first adjacent cell and the second adjacent cell. A method for manufacturing an energy storage module according to claim 1.

4. The first inspection step includes a vacuum inspection step that simultaneously performs the first airtightness test and the second airtightness test by evacuating the first adjacent cell and the second adjacent cell and measuring whether or not there is a pressure change in the first cell. A method for manufacturing an energy storage module according to claim 1.

5. The multiple cells to be inspected are divided into multiple groups, including the first cell, the first adjacent cell, and the second adjacent cell, and the gas inspection process is performed for each group. The method for manufacturing an energy storage module according to claim 3.

6. The multiple cells to be inspected are divided into multiple groups, including the first cell, the first adjacent cell, and the second adjacent cell, and the vacuum inspection process is performed for each group. The method for manufacturing an energy storage module according to claim 4.

7. A second inspection step is provided, which is performed after the arrangement step and before the first inspection step, in which the chamber is evacuated and the presence or absence of pressure changes in all the cells under inspection is measured. A method for manufacturing an energy storage module according to claim 1.

8. The system includes a third inspection step, which, after the first inspection step, measures the amount of gas leakage due to the differential pressure between all the cells under inspection and the chamber. A method for manufacturing an energy storage module according to any one of claims 1 to 7.