Energy storage device and method for manufacturing an energy storage device

Abstract

The present invention provides a power storage device capable of suppressing the occurrence of gaps between the outer casing and the cover member, and a method for manufacturing the power storage device. [Solution] The energy storage device 1 comprises an energy storage module 1A, a cover member 101, and an outer pack 90 that houses the energy storage module 1A and the cover member 101. The outer pack 90 has a first outer pack 90A and a second outer pack 90B. The first outer pack 90A includes a first recess 91A and a first flange portion 92A, and the second outer pack 90B includes a second recess 91B and a second flange portion 92B. The cover flange portion 101F of the cover member 101 is sandwiched and joined between the first flange portion 92A and the second flange portion 92B.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a power storage device. This power storage device includes an electrode laminate in which a plurality of bipolar electrodes are laminated, and an exterior body that seals the electrode laminate. The exterior body seals a high tensile stress member together with the electrode laminate. The high tensile stress member is inserted into the interior of the exterior body so as to sandwich the electrode laminate from both sides in a direction intersecting the lamination direction of the bipolar electrodes in the electrode laminate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a power storage device configured by housing a power storage module including a plurality of electrodes laminated on each other in an exterior body, for example, in order to ensure insulation, a cover member may be disposed between the inner surface of the housing portion of the power storage module in the exterior body and the power storage module. In this case, if a gap is formed between the exterior body and the cover member, for example, wrinkles may occur on the exterior body during the vacuum sealing of the exterior body. Therefore, in the above technical field, there is a demand for suppressing the occurrence of a gap between the exterior body and the cover member.

[0005] Therefore, an object of the present disclosure is to provide a power storage device and a method for manufacturing the same that can suppress the occurrence of a gap between the exterior body and the cover member.

Means for Solving the Problems

[0006] The energy storage device according to this disclosure comprises an energy storage module including a plurality of electrodes stacked along a first direction, a cover member arranged adjacent to the energy storage module when viewed from the first direction, and an outer casing that houses the energy storage module and the cover member. The outer casing includes a housing portion that houses the energy storage module and the cover member, and an outer flange portion that surrounds the housing portion when viewed from the first direction. The cover member includes a main body portion and a cover flange portion provided on the main body portion, and the cover flange portion is joined to the outer flange portion.

[0007] Furthermore, the present disclosure relates to a method for manufacturing an energy storage device, comprising: an energy storage module including a plurality of electrodes stacked along a first direction; a cover member having a main body and a cover flange portion provided on the main body; and an exterior body for housing the energy storage module and the cover member, the method comprising: a first step of preparing a bar member; and a second step after the first step of housing the energy storage module and the cover member in the exterior body and joining the cover member and the exterior body, wherein the exterior body includes a housing portion and an exterior flange portion surrounding the housing portion when viewed from the first direction, and in the second step, the energy storage module and cover are housing in the housing portion and the cover flange portion is joined to the exterior flange portion.

[0008] In this energy storage device and method for manufacturing it, cover members are arranged adjacent to energy storage modules and housed in an outer casing. The main body of the cover member is provided with a flange portion (cover flange portion). The outer casing includes a housing portion for housing the energy storage modules and cover members, and a flange portion surrounding the housing portion. The flange portion of the cover member is joined to the flange portion of the outer casing. This positions the cover member relative to the outer casing. Therefore, in this energy storage device and method for manufacturing it, the occurrence of gaps between the outer casing and the cover member is suppressed.

[0009] In the energy storage device according to this disclosure, the exterior body has a first exterior body and a second exterior body arranged to sandwich the energy storage module and cover member from both sides in a first direction, the first exterior body includes a first housing portion for housing the energy storage module and cover member and a first exterior flange portion that surrounds the first housing portion when viewed from the first direction, the second exterior body includes a second housing portion for housing the energy storage module and cover member and a second exterior flange portion that surrounds the second housing portion when viewed from the first direction, the housing portion includes the first housing portion and the second housing portion, the exterior flange portion includes the first exterior flange portion and the second exterior flange portion, and the cover flange portion may be sandwiched between the first exterior flange portion and the second exterior flange portion and joined to the first exterior flange portion and the second exterior flange portion.

[0010] In the energy storage device according to this disclosure, the first outer casing and the second outer casing are bonded together by overlapping and joining the first outer flange portion and the second outer flange portion. The main body portion has a cover corner portion which is a corner portion facing the opposite side from the energy storage module when viewed from a first direction. The cover flange portion is provided at least at the cover corner portion such that it protrudes outward from the main body portion when viewed from a first direction. The cover corner portion may be sandwiched between the first outer flange portion and the second outer flange portion and joined to the first outer flange portion and the second outer flange portion when the cover corner portion is in contact with the outer corner portion which is at least one corner portion of the first housing portion and the second housing portion.

[0011] In the energy storage device according to this disclosure, the main body may include a resin and a filler added to the resin having a coefficient of linear expansion smaller than that of the resin.

[0012] In the energy storage device according to this disclosure, the amount of filler added to the cover flange portion may be less than the amount of filler added to the main body portion.

[0013] In the energy storage device according to this disclosure, the outer flange portion is made of a laminated member including a metal layer and a resin layer laminated on the metal layer, and the resin layers are stacked so that they are in contact with each other, and the cover flange portion may include a resin compatible with the resin layer of the laminated member.

[0014] In the energy storage device according to this disclosure, the corners of the cover and the corners of the exterior may have a curved shape that is convex outward when viewed from the first direction.

[0015] In the energy storage device according to this disclosure, the first housing section and the second housing section are recesses that house the energy storage module and the cover member, and the cover corners may be the corners of the first housing section and the second housing section, which are recesses.

[0016] In the energy storage device manufacturing method according to this disclosure, a cover member may be prepared in the first step by integrally forming the main body portion and the cover flange portion by injection molding.

[0017] In the energy storage device manufacturing method according to this disclosure, in the first step, a cover member including a main body and a cover flange that are integrated with each other may be prepared by insert molding of the cover flange portion onto the main body portion.

[0018] In the energy storage device manufacturing method according to this disclosure, in the first step, a cover member including a main body and a cover flange may be prepared by welding a cover flange to the main body.

[0019] In the energy storage device manufacturing method according to this disclosure, in the first step, a cover member including a main body and a cover flange is prepared by forming the main body and cover flange by two-color molding. [Effects of the Invention]

[0020] According to this disclosure, it is possible to provide an energy storage device that can suppress the occurrence of gaps between the outer casing and the cover member, and a method for manufacturing an energy storage device.

Brief Description of the Drawings

[0021] [Figure 1] FIG. 1 is a plan view schematically showing an example of an electricity storage device. [Figure 2] FIG. 2 is a schematic view showing one outer surface of an electricity storage module. [Figure 3] FIG. 3 is a schematic cross-sectional view of an example of an electricity storage module. [Figure 4] FIG. 4 is a schematic enlarged cross-sectional view along the XY plane of region AR in FIG. 1. [Figure 5] FIG. 5 is a cross-sectional view along line V-V in FIG. 1. [Figure 6] FIG. 6 is a flowchart showing one step of a method for manufacturing an electricity storage device according to the present embodiment.

Modes for Carrying Out the Invention

[0022] Hereinafter, an embodiment will be described with reference to the drawings. In the description of the drawings, the same or equivalent elements may be denoted by the same reference numerals, and redundant descriptions may be omitted. Further, in the description, a rectangular coordinate system defined by the X-axis, Y-axis, and Z-axis shown in the drawings may be referred to.

[0023] FIG. 1 is a schematic plan view showing an electricity storage device according to the present embodiment. The electricity storage device 1 can be used, for example, as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The electricity storage device 1 is, for example, a secondary battery such as a nickel-hydrogen secondary battery or a lithium-ion secondary battery. The electricity storage device 1 may be an electric double layer capacitor or an all-solid-state battery. Here, the case where the electricity storage device 1 is a lithium-ion secondary battery is shown.

[0024] The energy storage device 1 comprises an energy storage module 1A, a cover member 100, a connector unit 30, and an outer packaging pack 90. ​​The energy storage module 1A has a rectangular shape when viewed from the Z-axis direction (first direction) and has four outer surfaces 20s extending in the Z-axis direction. That is, the energy storage module 1A has a roughly rectangular parallelepiped shape and has an upper surface 10a (first surface) and a lower surface 10b (first surface) that intersect in the Z-axis direction (see Figure 3), outer surfaces 20sA and 20sB (second surfaces) that intersect in the Y-axis direction (second direction), and outer surfaces 20sC and 20sD (third surfaces) that intersect in the X-axis direction (third direction). The upper surface 10a and the lower surface 10b face each other in the Z-axis direction, outer surfaces 20sA and 20sB face each other in the Y-axis direction, and outer surfaces 20sC and 20sD face each other in the X-axis direction. The upper surface 10a and the lower surface 10b have a positive terminal electrode 12 and a negative terminal electrode 13, respectively, as will be described later, and are used for power extraction.

[0025] One example of a cover member 100 is composed of cover member 101, cover member 102, and cover member 103. Cover members 101, 102, and 103 are arranged adjacent to the energy storage module 1A along the Y-axis direction. More specifically, cover members 101 and 102 are arranged to cover the outer surface 20sA when viewed from the Y-axis direction. Cover member 103 is arranged to cover the outer surface 20sB when viewed from the Y-axis direction. The connector unit 30 is arranged between cover member 101 and cover member 102 in the X-axis direction.

[0026] Figure 2 is a schematic diagram showing one outer surface 20sA of the energy storage module 1A. Figure 3 is a schematic cross-sectional view of an example of the energy storage module 1A, showing a cross-section along the line III-III in Figure 2. The outer surface 20sA of the energy storage module 1A includes a region R1 on which an additional member 50, described later, is provided, and regions R2 and R3 adjacent to region R1. In the example shown in Figure 2, region R2 is located on the negative side in the X-axis direction compared to region R1, and region R3 is located on the positive side in the X-axis direction compared to region R1. The additional member includes an injection port 53A used when injecting electrolyte into the energy storage module 1A.

[0027] As shown in Figure 3, the energy storage module 1A includes an electrode stack 10 and a sealing body 29 that surrounds the electrode stack 10 when viewed from the Z-axis direction. The electrode stack 10 includes a plurality of electrodes stacked along the Z-axis direction. The Z-axis direction is the direction in which the electrodes are stacked and is the height direction of the energy storage device 1. The plurality of electrodes include a plurality of bipolar electrodes 11, a positive terminal electrode 12, and a negative terminal electrode 13. Separators 14 are interposed between adjacent electrodes. The positive terminal electrode 12 constitutes part of the upper surface 10a of the energy storage module 1A, and the negative terminal electrode 13 constitutes part of the lower surface 10b of the energy storage module 1A.

[0028] The bipolar electrode 11 comprises a current collector 15, a positive electrode active material layer 16, and a negative electrode active material layer 17. The current collector 15 is rectangular in shape when viewed from the Z-axis direction and is in the form of a sheet. The active material layers (positive electrode active material layer 16, negative electrode active material layer 17) are located in the center of the current collector 15 when viewed from the Z-axis direction and are not located on the peripheral edge 15c of the current collector 15. The positive electrode active material layer 16 is located on the first surface 15a of the current collector 15. The negative electrode active material layer 17 is located on the second surface 15b of the current collector 15. The first surface 15a of the current collector 15 faces the other side in the Z-axis direction (the side where the negative electrode terminal electrode 13 is located in Figure 3), and the second surface 15b of the current collector 15 faces the one side in the Z-axis direction (the side where the positive electrode terminal electrode 12 is located in Figure 3). Multiple bipolar electrodes 11 are stacked such that the positive electrode active material layer 16 of one adjacent bipolar electrode 11 and the negative electrode active material layer 17 of the other bipolar electrode 11 face each other in the stacking direction.

[0029] The positive terminal electrode 12 comprises a current collector 15 and a positive electrode active material layer 16 provided on the first surface 15a of the current collector 15. The second surface 15b of the current collector 15 of the positive terminal electrode 12 does not have an active material layer. The positive terminal electrode 12 is laminated on the bipolar electrode 11 at one end of the electrode stack 10 in the Z-axis direction. The positive terminal electrode 12 is laminated on the bipolar electrode 11 such that its positive electrode active material layer 16 faces the negative electrode active material layer 17 of the bipolar electrode 11.

[0030] The negative electrode terminal electrode 13 comprises a current collector 15 and a negative electrode active material layer 17 provided on the second surface 15b of the current collector 15. The first surface 15a of the current collector 15 of the negative electrode terminal electrode 13 does not have an active material layer. The negative electrode terminal electrode 13 is laminated on the bipolar electrode 11 at the end of the electrode laminate 10 in the Z-axis direction, opposite to the side on which the positive electrode terminal electrode 12 is provided. The negative electrode terminal electrode 13 is laminated on the bipolar electrode 11 such that its negative electrode active material layer 17 faces the positive electrode active material layer 16 of the bipolar electrode 11. In this embodiment, the current collectors of the bipolar electrode 11, positive electrode terminal electrode 12, and negative electrode terminal electrode 13 are all denoted by the same reference numeral as current collector 15, but the current collectors of the bipolar electrode 11, positive electrode terminal electrode 12, and negative electrode terminal electrode 13 may be the same as or different from each other.

[0031] The separator 14 is positioned between adjacent bipolar electrodes 11, between the positive terminal electrode 12 and the bipolar electrode 11, and between the negative terminal electrode 13 and the bipolar electrode 11. The separator 14 is interposed between the positive electrode active material layer 16 and the negative electrode active material layer 17, separating them. The separator 14 prevents short circuits caused by contact between adjacent electrodes while allowing charge carriers such as lithium ions to pass through.

[0032] The current collector 15 is a chemically inert electrical conductor that allows current to continue flowing through the positive electrode active material layer 16 and the negative electrode active material layer 17 during the discharge or charging of the lithium-ion secondary battery. The material of the current collector 15 is, for example, a metal material, a conductive resin material, or a conductive inorganic material. Examples of conductive resin materials include conductive polymer materials or resins to which conductive fillers are optionally added to non-conductive polymer materials. The current collector 15 may comprise multiple layers. In this case, each layer of the current collector 15 may contain the above-mentioned metal material or conductive resin material.

[0033] A coating layer may be formed on the surface of the current collector 15. This coating layer may be formed by known methods such as plating or spray coating. The current collector 15 may be in the form of a plate, foil (e.g., metal foil), film, or mesh. Examples of metal foils include aluminum foil, copper foil, nickel foil, titanium foil, or stainless steel foil. The current collector 15 may be an alloy foil or clad foil of the above metals. If the current collector 15 is in the form of a foil, its thickness may be, for example, 1 μm to 100 μm. In this embodiment, the current collector 15 is a foil in which aluminum foil and copper foil are integrated, or aluminum foil.

[0034] The positive electrode active material layer 16 contains a positive electrode active material capable of intercalating and releasing charge carriers such as lithium ions. Examples of positive electrode active materials include lithium composite metal oxides having a layered rock salt structure, metal oxides having a spinel structure, and polyanionic compounds. The positive electrode active material can be any material suitable for use in lithium-ion secondary batteries. The positive electrode active material layer 16 may contain multiple positive electrode active materials. In this embodiment, the positive electrode active material layer 16 contains olivine-type lithium iron phosphate (LiFePO4) as a composite oxide.

[0035] The negative electrode active material layer 17 contains a negative electrode active material capable of intercalating and releasing charge carriers such as lithium ions. The negative electrode active material may be an element, an alloy, or a compound. Examples of negative electrode active materials include Li, carbon, and metal compounds. The negative electrode active material may also be an element or compound thereof that can be alloyed with lithium. Examples of carbon include natural graphite, artificial graphite, hard carbon (carbon that is difficult to graphitize), or soft carbon (carbon that is easily graphitized). Examples of artificial graphite include highly oriented graphite and mesocarbon microbeads. Examples of elements that can be alloyed with lithium include silicon or tin. In this embodiment, the negative electrode active material layer 17 contains graphite as a carbon-based material.

[0036] Each of the positive electrode active material layer 16 and the negative electrode active material layer 17 (hereinafter sometimes simply referred to as the "active material layer") may further contain, as necessary, conductive additives, binders, electrolytes (polymer matrix, ion-conducting polymer, electrolyte solution, etc.), electrolyte-supporting salts (lithium salts) to enhance ionic conductivity, etc. Conductive additives are added to enhance the conductivity of each electrode (bipolar electrode 11, positive electrode terminal electrode 12, negative electrode terminal electrode 13). Examples of conductive additives include acetylene black, carbon black, or graphite.

[0037] Examples of binders include fluororesins 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 or methacrylic acid; styrene-butadiene rubber (SBR); alginates such as carboxymethylcellulose, sodium alginate, and ammonium alginate; water-soluble cellulose ester crosslinked polymers; and starch-acrylic acid graft polymers. These binders can be used individually or in combination. Examples of solvents include water and N-methyl-2-pyrrolidone (NMP).

[0038] The separator 14 may be, for example, a porous sheet or nonwoven fabric containing a polymer that absorbs and retains electrolytes. Examples of materials for the separator 14 include polypropylene, polyethylene, polyolefin, and polyester. The separator 14 may have a single-layer structure or a multilayer structure. The multilayer structure may include, for example, a ceramic layer as an adhesive layer or a heat-resistant layer. The separator 14 may be impregnated with an electrolyte. The separator 14 may be composed of an electrolyte such as a polymer electrolyte or an inorganic electrolyte. Examples of electrolytes impregnated into the separator 14 include a liquid electrolyte (electrolyte solution) containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent, or a polymer gel electrolyte containing an electrolyte held in a polymer matrix.

[0039] When the separator 14 is impregnated with an electrolyte, known lithium salts such as LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, and LiN(CF3SO2)2 may be used as the electrolyte salt. Furthermore, known solvents such as cyclic carbonates, cyclic esters, linear carbonates, linear esters, and ethers may be used as the non-aqueous solvent. Two or more of these known solvent materials may be used in combination.

[0040] The sealing body 29 includes a sealing main body 20 and an additional member 50. The sealing main body 20 is formed in a frame shape on the periphery of the electrode stack 10 so as to surround the periphery of the electrode stack 10 when viewed from the Z-axis direction. The sealing main body 20 can be joined to the first surface 15a and the second surface 15b of each current collector 15 at the peripheral edge 15c of each current collector 15. The sealing main body 20 can form an internal space S between adjacent current collectors 15 in the Z-axis direction and can seal each of these internal spaces S. In this embodiment, each internal space S contains an electrolyte (not shown). That is, the sealing main body 20 cooperates with adjacent current collectors 15 in the Z-axis direction to define the internal space S in which the electrolyte is contained. The sealing main body 20 can prevent the electrolyte contained in the internal space S from flowing out to the outside.

[0041] The sealing body portion 20 can suppress the intrusion and discharge of air, moisture, etc., between the outside and the internal space S of the electrode stack 10. The sealing body portion 20 can, for example, suppress the leakage of gas generated at each electrode due to charge-discharge reactions, etc., to the outside of the energy storage module 1A. The edges of the separator 14 are joined to the sealing body portion 20. The sealing body portion 20 contains an insulating material. Examples of materials for the sealing body portion 20 include various resin materials such as polypropylene, polyethylene, polystyrene, ABS resin, acid-modified polypropylene, acid-modified polyethylene, and acrylonitrile styrene resin.

[0042] An example of a sealing body 20 includes a plurality of sealing materials 21, a pair of end sealing materials 24, and a plurality of spacers 22. The sealing materials 21, end sealing materials 24, and spacers 22 may be frame-shaped members formed in a sheet-like manner. The sealing body 20 also has a welded end 23. The sealing material 21 is frame-shaped when viewed from the Z-axis direction and is provided along the peripheral edge 15c of the current collector 15. The sealing material 21 is provided so as to extend from the first surface 15a of the current collector 15 through the end surface to the second surface 15b, covering the peripheral edge 15c. That is, the sealing material 21 has an inner portion that overlaps the current collector 15 and an outer portion that is located outside the edge of the current collector 15 when viewed from the Z direction on the first surface 15a and the second surface 15b of the current collector 15, and the outer portions of a pair of adjacent sealing materials 21 on either side of the current collector 15 are connected. The sealing material 21 can be welded to at least one of the first surface 15a and the second surface 15b of the current collector 15. In this embodiment, the sealing material 21 is welded to both the first surface 15a and the second surface 15b of the current collector 15.

[0043] The end seal material 24 has a frame shape when viewed from the Z-axis direction and is provided along the peripheral edge 15c of the current collector 15 that constitutes the positive terminal electrode 12 and the negative terminal electrode 13, respectively. Therefore, the end seal material 24 is arranged to sandwich the multiple seal materials 21 from the Z-axis direction. The end seal material 24 can be welded to at least one of the first surface 15a and the second surface 15b of the current collector 15. In this embodiment, the end seal material 24 is welded to both the first surface 15a and the second surface 15b of the current collector 15.

[0044] The spacer 22 has a frame shape when viewed from the Z-axis direction and is positioned along the peripheral edge 15c of the current collector 15. The spacer 22 is positioned to be interposed between adjacent sealing materials 21 in the Z-axis direction. Furthermore, the spacer 22 is positioned to be interposed between adjacent sealing materials 21 and end sealing materials 24 in the Z-axis direction. The spacer 22 can maintain the distance between adjacent current collectors 15 in the Z-axis direction. That is, the spacer 22, sealing materials 21 and end sealing materials 24 define an internal space S between adjacent current collectors 15.

[0045] The welded end 23 is formed by welding together the ends of the multiple sealing materials 21, the pair of end sealing materials 24, and the multiple spacers 22 that are opposite to the internal space S, thereby integrating them. When viewed from the Z-axis direction, the welded end 23 has a frame-like shape that surrounds the electrode stack 10. The side of the welded end 23 opposite to the internal space S extends along the Z-axis direction and constitutes the outer surface 20s of the sealing body portion 20. In other words, the sealing body portion 20 includes the outer surface 20s opposite to the internal space S. The outer surface 20s may be formed as a flat surface.

[0046] The sealing body portion 20 has a plurality of communication holes 27 that communicate with each of the plurality of internal spaces S. For example, the communication holes 27 are notched portions formed in the spacer 22 and are formed to penetrate the welded end portion 23. The communication holes 27 have one opening in the internal space S and the other opening in the outer surface 20s of the sealing body portion 20. In the illustrated example, the opening is formed in the outer surface 20sA.

[0047] The additional member 50 is formed to overlap the region R1 on the outer surface 20sA where the communication holes 27 are formed. By being molded into a predetermined shape, the additional member 50 provides a liquid injection port portion 53A having a plurality of liquid injection ports that communicate with each of the plurality of communication holes 27. The additional member 50 is joined to the welded end portion 23. For example, the additional member 50 is integrally joined to the welded end portion 23 by injection molding. An example of the additional member 50 includes a main body portion 51, a first overhang portion 55, and a second overhang portion 57.

[0048] The main body 51 partially covers the outer surface 20sA. For example, the main body 51 covers the outer surface 20sA such that it includes a region R1 in which multiple communication holes 27 are formed. As described above, each of the multiple communication holes 27 communicates with a plurality of internal spaces S. In the example shown in Figure 2, 30 communication holes 27 corresponding to 30 layers of internal space formed between each current collector 15 are arranged discretely in the X-axis and Z-axis directions. More specifically, the communication holes 27 corresponding to the 1st to 10th layers of internal space are arranged evenly spaced along the X-axis, with the positive terminal electrode 12 side as the base end, while the communication holes 27 corresponding to the 11th to 20th layers of internal space, and the communication holes 27 corresponding to the 21st to 30th layers of internal space are arranged sequentially in the Z-axis direction below the 1st to 10th layers of internal space. The main body portion 51 extends in a rectangular shape along the X-axis and Z-axis directions in order to cover the region R1 in which these 30 communication holes 27 are formed.

[0049] The main body portion 51 is formed in the shape of a rectangular plate with a predetermined thickness in the Y-axis direction. The main body portion 51 has openings 52 at positions corresponding to the communication holes 27. The main body portion 51 also has protruding frame portions 53 that project in the Y-axis direction, intersecting (orthogonal to) the outer surface 20sA. When viewed from the Y-axis direction, the protruding frame portions 53 surround each opening 52 and function as partition walls separating each opening 52. In the example in Figure 2, ten protruding frame portions 53 are arranged in the X-axis direction, each having three spaces to separate three vertically aligned openings 52.

[0050] The protruding frame portion 53 is used, for example, when injecting electrolyte into each of the internal spaces S. For example, when injecting electrolyte, the nozzle of the injection device is brought into close contact with the top surface of the protruding frame portion 53, and the electrolyte is introduced into the space of each protruding frame portion 53 from the nozzle. This makes it possible to inject electrolyte into the internal space S from the opening 52 and the communication hole 27. After the electrolyte is injected, a laminate sheet 54 may be provided on the protruding frame portion 53 to seal it. The laminate sheet 54 may be, for example, a sheet in which a metal layer such as aluminum is covered with a resin layer. The laminate sheet 54 may be fused to, for example, the top surface of the protruding frame portion 53.

[0051] In one example, the main body 51 includes a terminal section 58 for voltage detection (see Figure 2). The terminal section 58 is formed in the main body 51 at a position offset to the positive side in the X-axis direction from the liquid injection port section 53A, which is composed of a plurality of protruding frame sections 53. For example, the terminal section 58 is provided adjacent to a protruding frame section 53 formed at the positive end in the X-axis direction, via a flat surface 51a. In one example, the terminal section 58 is provided at the positive end in the X-axis direction of the main body 51. The terminal section 58 provides a plurality of terminals 58a that are electrically connected to a plurality of current collectors 15. One end of each terminal 58a is connected to the corresponding current collector 15, and the other end of each terminal 58a is exposed from the main body 51. The terminals 58a only need to be electrically connected to the current collectors 15, and may be, for example, metal pins. A connector unit 30 (see Figure 1) is fixed to the terminal section 58. One example of a connector unit 30 includes a housing 31 having multiple contacts connected to multiple terminals 58a, and a connector 33 connected to the housing 31. A flexible circuit board may be connected to the connector 33, which is pulled out to the outside of the outer packaging pack 90.

[0052] The first overhang portion 55 and the second overhang portion 57 are formed by connecting to both ends of the main body portion 51 in the Z-axis direction. The first overhang portion 55 partially covers one end of the welded end portion 23 in the Z-axis direction (the positive Z-axis side). For example, the first overhang portion 55 partially covers the end seal material 24 joined to the positive electrode terminal 12. In the illustrated example, the end edge 55a of the first overhang portion 55 extends from the end edge of the welded end portion 23 to a position outside the inner edge 22a of the spacer 22 and the inner edge 21a of the seal material 21 when viewed from the Z-axis direction, but this is not limited to this. The first overhang portion 55 may be formed in the shape of a rectangular plate having the same length as the main body portion 51 in the X-axis direction. Similarly to the first overhang portion 55, the second overhang portion 57 partially covers the other end of the welded end portion 23 in the Z-axis direction (the negative Z-axis side).

[0053] Figure 4 is a simulated enlarged cross-sectional view of region AR in Figure 1 along the XY plane. Figure 5 is a cross-sectional view along the VV line in Figure 1. In Figures 4 and 5, the energy storage module 1A included in the energy storage device 1 is depicted in a simplified manner. An example of an outer pack 90 (outer body) includes a first outer pack 90A (first outer body) and a second outer pack 90B (second outer body) arranged to face each other in the vertical direction, and houses the energy storage module 1A and cover members 101, 102, 103 (and also the connector unit 30 (hereinafter the same)). The first outer pack 90A and the second outer pack 90B are arranged to sandwich the energy storage module 1A and cover members 101, 102, 103 from both sides in the Z-axis direction.

[0054] The first outer packaging 90A has a first recess 91A (first housing portion) for housing the energy storage module 1A and cover members 101, 102, and 103, and a first flange portion 92A (first outer flange portion) surrounding the first recess 91A when viewed from the Z-axis direction. The first recess 91A includes a conductive member 95A and an outer film 96A. Here, the first recess 91A is composed of the conductive member 95A and the outer film 96A. The first flange portion 92A includes an outer film 96A. Here, the first flange portion 92A is composed of the outer film 96A.

[0055] The conductive member 95A has a rectangular shape when viewed from the Z-axis direction and constitutes the central part of the bottom of the first recess 91A. The conductive member 95A abuts against the second surface 15b of the current collector 15 of the positive terminal electrode 12 and is electrically connected to the positive terminal electrode 12. The conductive member 95A may be, for example, a metal foil, and one example may be aluminum foil. The planar size of the conductive member 95A may be the same as or smaller than that of the current collector 15.

[0056] The outer film 96A forms the periphery of the first recess 91A when viewed from the Z-axis direction. The outer film 96A is configured to surround the outer periphery of the contents (in this case, the energy storage module 1A, the cover member 100, and the connector unit 30) when viewed from the Z-axis direction. The outer film 96A is connected to the periphery of the conductive member 95A. The outer film 96A has a rectangular frame shape when viewed from the Z-axis direction. For example, the outer film 96A may be formed by welding together four strip-shaped sheet members along each of the four sides that make up the rectangle.

[0057] The inner edge of the rectangular frame-shaped outer film 96A, viewed from the Z-axis direction, is located inside the periphery of the conductive member 95A. The inner edge of the outer film 96A and the periphery of the conductive member 95A are joined together in an overlapping manner. In one example, the inner edge of the outer film 96A and the periphery of the conductive member 95A may be joined together by a resin material 97. The resin material 97 may be a rectangular frame-shaped sealing resin formed in a sheet. For example, the inner edge of the rectangular frame-shaped resin material 97 may be located inside the inner edge of the outer film 96A, and the outer edge of the resin material 97 may coincide with the periphery of the conductive member 95A. The outer edge of the outer film 96A is located outside the periphery of the contents, viewed from the Z-axis direction.

[0058] The outer film 96A may be, for example, a laminate film including a metal layer. That is, the outer film 96A may be a sheet-like member in which both sides of a metal layer 96a, such as aluminum, are covered with resin layers 96b and 96c. In other words, the outer film 96A is composed of a laminate member including a metal layer 96a and resin layers 96b and 96c laminated on the metal layer 96a. The resin layers 96b and 96c may be formed of the same resin as the sealant 29.

[0059] The second outer packaging 90B has a second recess 91B (second housing section) for housing the energy storage module 1A and cover members 101, 102, and 103, and a second flange section 92B (second outer flange section) surrounding the second recess 91B when viewed from the Z-axis direction. The second recess 91B includes a conductive member 95B and an outer film 96B. Here, the second recess 91B is composed of the conductive member 95B and the outer film 96B. The second flange section 92B includes an outer film 96B. Here, the second flange section 92B is composed of the outer film 96B. Thus, the outer packaging 90 has a housing section including the first recess 91A and the second recess 91B, and an outer flange section including the first flange section 92A and the second flange section 92B.

[0060] The conductive member 95B has a rectangular shape when viewed from the Z-axis direction and constitutes the central part of the bottom of the second recess 91B. The conductive member 95B abuts against the first surface 15a of the current collector 15 of the negative terminal electrode 13 and is electrically connected to the negative terminal electrode 13. The conductive member 95B may be, for example, a metal foil, and one example may be aluminum foil. The planar size of the conductive member 95B may be the same as or smaller than that of the current collector 15.

[0061] The outer film 96B forms the periphery of the second recess 91B when viewed from the Z-axis direction. The outer film 96B is configured to surround the outer periphery of the contents (in this case, the energy storage module 1A, the cover member 100, and the connector unit 30) when viewed from the Z-axis direction. The outer film 96B is connected to the periphery of the conductive member 95B. The outer film 96B has a rectangular frame shape when viewed from the Z-axis direction. For example, the outer film 96B may be formed by welding together four strip-shaped sheet members along each of the four sides that make up the rectangle.

[0062] The inner edge of the outer film 96B, which forms a rectangular frame when viewed from the Z-axis direction, is located inside the periphery of the conductive member 95B. The inner edge of the outer film 96B and the periphery of the conductive member 95B are joined together in an overlapping manner. In one example, the inner edge of the outer film 96B and the periphery of the conductive member 95B may be joined together by a resin material 97. The resin material 97 may be a rectangular frame-shaped sealing resin formed in a sheet. For example, the inner edge of the rectangular frame-shaped resin material 97 may be located inside the inner edge of the outer film 96B, and the outer edge of the resin material 97 may coincide with the periphery of the conductive member 95B. The outer edge of the outer film 96B is located outside the periphery of the contents when viewed from the Z-axis direction.

[0063] The outer film 96B may be, for example, a laminate film including a metal layer. That is, the outer film 96B may be a sheet-like member in which both sides of a metal layer 96a, such as aluminum, are covered with resin layers 96b and 96c. In other words, the outer film 96B is composed of a laminate member including a metal layer 96a and resin layers 96b and 96c laminated on the metal layer 96a. The resin layers 96b and 96c may be formed of the same resin as the sealant 29. The first outer pack 90A and the second outer pack 90B may be similarly configured, including the configuration of the conductive members 95A and 95B, and the configuration of the outer films 96A and 96B.

[0064] The first outer packaging 90A and the second outer packaging 90B are bonded together by overlapping and joining the first flange portion 92A and the second flange portion 92B. As a result, the first recess 91A and the second recess 92 form a space for accommodating the contents. When viewed from the Z-axis direction, the outer corner portion 90C, which is the corner of the first recess 91A and the second recess 91B, is a curved surface that is convex outward (i.e., it is a rounded surface).

[0065] Next, the cover member 100 will be described. The cover member 100 is housed in the outer pack 90 together with the energy storage module 1A and the connector unit 30, positioned between the outer surface 20s of the energy storage module 1A and the outer films 96A and 96B. The cover member 100 is positioned to cover the outer surface 20s of the energy storage module 1A when viewed from the Y-axis direction. A gap may be formed between the cover member 100 and the outer surface 20s in the Y-axis direction.

[0066] In one example of a power storage device 1, the cover member 100 is composed of cover member 101 and cover member 102, which are positioned between the outer surface 20sA of the power storage module 1A and the outer films 96A and 96B, and cover member 103, which is positioned between the outer surface 20sB of the power storage module 1A and the outer film 96. Cover member 101 is positioned on the positive side in the X-axis direction relative to the connector unit 30. Cover member 102 is positioned on the negative side in the X-axis direction relative to the connector unit 30.

[0067] The cover member 101 includes base walls 111 and 121 extending along the Y-axis direction (more specifically, the XY plane), and side walls 112 and 113 extending along the Z-axis direction from both ends of the base wall 111 in the Y-axis direction to the base wall 121. The outer surface 111b of the base wall 111 faces the bottom surface of the first recess 91A of the first outer packaging pack 90A, the outer surface 121b of the base wall 121 faces the bottom surface of the second recess 91B of the second outer packaging pack 90B, and the outer surface 112b of the side wall 112 faces the inner surface of the first recess 91A of the first outer packaging pack 90A and the inner surface of the second recess 91B of the second outer packaging pack 90B. The first cover member 110 also has a side wall 114 extending along the Z-axis direction from the X-axis edge of the base wall 111. The base walls 111 and 121 intersect in the Z-axis direction, the side walls 112 and 113 intersect in the Y-axis direction, and the side wall 114 intersects in the X-axis direction.

[0068] The cover member 101 has a cover corner 101C, which is a corner that connects the side wall 112 and the side wall 114 when viewed from the Z-axis direction. The cover corner 101C is the corner that faces the opposite side from the energy storage module 1A when viewed from the Z-axis direction. In other words, the cover corner 101C is the corner that faces the exterior corner 90C, which is the corner of the first recess 91A and the second recess 91B. The cover corner 101C has a curved surface that is convex outward when viewed from the Z-axis direction (i.e., it is an R-surface). The exterior corner 90C and the cover corner 101C are substantially the same shape.

[0069] Here, the cover member 101 has a main body portion 101M and a cover flange portion 101F provided on the main body portion 101M. The main body portion 101M is composed of the base walls 111, 121 and side walls 112, 113, 114 described above, and is a hollow portion having an inner surface 111a and an outer surface 111b. Therefore, the main body portion 101M has a cover corner portion 101C. The cover flange portion 101F is provided at least on the cover corner portion 101C so as to protrude from the main body portion 101M to the outside of the main body portion 101M when viewed from the Z-axis direction. Here, the cover flange portion 101F is provided only on the cover corner portion 101C, so that it is formed in an L-shaped plate shape extending from the side wall 112 to the side wall 114 when viewed from the Z-axis direction.

[0070] The position of the cover flange portion 101F in the Z-axis direction is set to coincide with the joining position of the first flange portion 92A and the second flange portion 92B when the cover member 101 is housed in the first outer pack 90A and the second outer pack 90B. In the illustrated example, since the first flange portion 92A and the second flange portion 92B are joined in the Z-axis direction at the center of the cover member 101 (main body portion 101M), the cover flange portion 101F also protrudes from the center of the main body portion 101M.

[0071] The cover flange portion 101F is joined (e.g., welded) to the first flange portion 92A and the second flange portion 92B when the cover corner portion 101C is in contact with the outer corner portion 90C, which is the corner of the first recess 91A and the second recess 91B (that is, when the outer surface 111b of the main body portion 101M is in close contact with the inner surface of the outer pack 90). In other words, the first flange portion 92A and the second flange portion 92B are joined (e.g., welded) to each other with the cover flange portion 101F interposed between them. In this way, the cover flange portion 101F is joined to the outer flange portion.

[0072] The main body 101M and the cover flange 101F contain a resin such as PP (polypropylene) or PPS (polyphenyl sulfide). For example, the main body 101M consists of the resin and a filler added to the resin, which has a coefficient of linear expansion smaller than that of the resin. As a result, the coefficient of linear expansion of the main body 101M is smaller compared to when it is composed of resin alone. The filler is, for example, a glass filler.

[0073] The cover flange portion 101F may be composed of resin and a filler added to the resin, similar to the main body portion 101M. In this case, the amount of filler added to the cover flange portion 101F may be the same as the amount of filler added to the main body portion 101M, or it may be less than the amount of filler added to the main body portion 101M. In particular, the amount of filler added to the cover flange portion 101F may be zero. In this case, the cover flange portion 101F does not contain filler and consists only of, for example, resin.

[0074] Furthermore, the main body portion 101M and the cover flange portion 101F may be made of the same material or of different materials. For example, when the main body portion 101M and the cover flange portion 101F are integrally formed by injection molding, the main body portion 101M and the cover flange portion 101F may be made of the same resin (e.g., PP) to which a filler has been added. Alternatively, when they are integrally formed by insert molding of the cover flange portion 101F into the main body portion 101M, or when they are integrated by welding the cover flange portion 101F to the main body portion 101M, for example, the main body portion 101M may be made of a resin (e.g., PP) to which a filler has been added, and the cover flange portion 101F may be made of a resin (e.g., PP) to which a filler has been added. Furthermore, even when the main body portion 101M and the cover flange portion 101F are integrally formed by two-color molding, for example, the main body portion 101M may be made of a resin with filler added (e.g., PPS), and the cover flange portion 101F may be made of a resin without filler added (e.g., PP).

[0075] As described above, the cover flange portion 101F can be sandwiched between the first flange portion 92A and the second flange portion 92B and welded to the first flange portion 92A and the second flange portion 92B. In this case, the first flange portion 92A and the second flange portion 92B are overlapped so that their respective resin layers 96b are in contact. Therefore, the cover flange portion 101F can contain a resin compatible with the resin layer 96b.

[0076] The cover member 102 and the cover member 103 can also be configured in the same manner as the cover member 101 described above.

[0077] Next, an example of a method for manufacturing the energy storage device 1 described above will be explained. Figure 6 is a flowchart showing one step of the energy storage device manufacturing method according to this embodiment. As shown in Figure 6, first, a cover member 101 is prepared (step S101, first step). In step S101, for example, a mold for the main body portion 101M and the cover flange portion 101F may be prepared, and the cover member 101 may be prepared by integrally forming the main body portion 101M and the cover flange portion 101F by injection molding using the mold.

[0078] Alternatively, in step S101, for example, the cover flange portion 101F may be placed in a mold for the main body portion 101M while the main body portion 101M is injection molded using the mold, thereby insert molding the cover flange portion 101F into the main body portion 101M and preparing a cover member 101 including the main body portion 101M and the cover flange portion 101F which are integrated with each other.

[0079] Alternatively, in step S101, the main body portion 101M and the flange portion F may be prepared separately in advance, and the cover flange portion 101F may be welded to the main body portion 101M to prepare a cover member 101 that includes the main body portion 101M and the cover flange portion 101F integrated together. Furthermore, in step S101, the main body portion 101M and the cover flange portion 101F may be formed by two-color molding to prepare a cover member 101 that includes the main body portion 101M and the cover flange portion 101F integrated together.

[0080] As described above, in step S101, the cover member 101 can be prepared by any method. In addition, in step S101, the cover members 102 and 103 may be prepared in the same manner, and the energy storage module 1A and the outer pack 90 may be prepared separately.

[0081] In the next step, the energy storage module 1A and the cover member 101 (and also the cover members 102, 103 (hereinafter the same)) are housed in the outer pack 90, and the cover member 101 and the outer pack 90 are joined together (step S102, second step). More specifically, in step S102, the cover member 101 is first positioned so that it is adjacent to the energy storage module 1A along the Y-axis direction, and so that the cover corner 101C faces away from the energy storage module 1A when viewed from the Z-axis direction, and the energy storage module 1A and the cover member 101 are positioned in the first recess 91A of the first outer pack 90A (first positioning step).

[0082] Next, the second outer pack 90B is placed on top of the first outer pack 90A so as to sandwich the energy storage module 1A and the cover member 101 from both sides in the Z-axis direction (step S103, second placement step). Here, the second outer pack 90B is placed on top of the first outer pack 90A so that the first flange portion 92A and the second flange portion 92B overlap each other. At this time, the cover corner portion 101C is in contact with the outer corner portion 90C, and the cover flange portion 101F is sandwiched between the first flange portion 92A and the second flange portion 92B.

[0083] Subsequently, with the cover corner portion 101C in contact with the exterior corner portion 90C, and the cover flange portion 101F sandwiched between the first flange portion 92A and the second flange portion 92B, the first flange portion 92A, the second flange portion 92B, and the cover flange portion 101F are joined to each other (for example, welded) (step S104, joining step).

[0084] As described above, in the energy storage device 1 and the method for manufacturing the energy storage device, the cover member 101 is positioned adjacent to the energy storage module 1A, and they are housed in the outer pack 90. ​​The main body portion 101M of the cover member 101 is provided with a flange portion (cover flange portion 101F). The outer pack 90 includes a housing portion (first recess 91A and second recess 91B) for housing the energy storage module 1A and the cover member 101, and a flange portion (first flange portion 92A and second flange portion 92B) surrounding the housing portion. The cover flange portion 101F of the cover member 101 is joined to the flange portion of the outer pack 90. ​​This positions the cover member 101 relative to the outer pack 90. ​​Therefore, in this energy storage device 1 and the method for manufacturing the energy storage device, the occurrence of a gap between the outer pack 90 and the cover member 101 is suppressed.

[0085] Furthermore, in the energy storage device 1 according to this embodiment, the outer pack 90 has a first outer pack 90A and a second outer pack 90B arranged to sandwich the energy storage module 1A and the cover member 101 from both sides in the Z-axis direction. The first outer pack 90A includes a first recess 91A for housing the energy storage module 1A and the cover member 101, and a first flange portion 92A that surrounds the first recess 91A when viewed from the Z-axis direction. The second outer pack 90B includes a second recess 91B for housing the energy storage module 1A and the cover member 101, and a second flange portion 92B that surrounds the second recess 91B when viewed from the Z-axis direction. The cover flange portion 101F is sandwiched between the first flange portion 92A and the second flange portion 92B and joined to the first flange portion 92A and the second flange portion 92B. Therefore, the flange portion of the cover member 101 is sandwiched and joined between the first flange portion 92A and the second flange portion 92B of the outer packaging pack 90, so that the cover member 101 is reliably positioned relative to the outer packaging pack 90.

[0086] Furthermore, in the energy storage device 1 according to this embodiment, the first outer pack 90A and the second outer pack 90B are bonded together by overlapping and joining the first flange portion 92A and the second flange portion 92B, and the main body portion 101M has a cover corner portion 101C which is a corner portion facing the opposite side from the energy storage module 1A when viewed from the Z-axis direction. The cover flange portion 101F is provided at least on the cover corner portion 101C so as to protrude outward from the main body portion 101M when viewed from the Z-axis direction, and when the cover corner portion 101C is in contact with the outer corner portion 90C which is at least one corner portion of the first recess 91A and the second recess 91B, it is sandwiched between the first outer flange portion and the second outer flange portion and joined to the first flange portion 92A and the second flange portion 92B. Therefore, the flange portion of the cover member 101 is joined by being sandwiched between the first flange portion 92A and the second flange portion 92B when the cover corner portion 101C, which is the corner of the main body portion 101M of the cover member 101, is in contact with the outer corner portion 90C, which is the corner of the first recess 91A and the second recess 91B of the outer pack 90. ​​As a result, the cover member 101 is positioned relative to the outer pack 90 in a state where it is in contact with the inner surface of the outer pack 90. ​​Thus, in this energy storage device 1 and the method for manufacturing the energy storage device, the occurrence of a gap between the outer pack 90 and the cover member 101 is suppressed.

[0087] Furthermore, in the energy storage device 1 according to this embodiment, the main body 101M includes resin and a filler added to the resin, which has a coefficient of linear expansion smaller than that of the resin. As a result, the coefficient of linear expansion of the main body 101M is made smaller compared to the case where the main body 101M consists only of resin. As a result, the difference in the coefficient of linear expansion between the main body 101M and the outer films 96A, 96B (i.e., the metal layer 96a) is reduced, and stress generated from the main body 101M to the outer films 96A, 96B during expansion and contraction of the main body 101M can be suppressed.

[0088] In the energy storage device 1 according to this embodiment, the amount of filler added to the cover flange portion 101F may be smaller than the amount of filler added to the main body portion 101M. In this case, the sealing performance between the cover flange portion 101F and the first flange portion 92A and the second flange portion 92B is improved because the amount of filler added to the cover flange portion 101F becomes relatively small (or even zero).

[0089] In the energy storage device 1 according to this embodiment, the first flange portion 92A and the second flange portion 92B are made of a laminated member including a metal layer 96a and resin layers 96b and 96c laminated on the metal layer 96a, and are stacked so that the resin layers 96b of each other are in contact, and the cover flange portion 101F may contain a resin compatible with the resin layer 96b. In this case, welding of the cover flange portion 101F with the first flange portion 92A and the second flange portion 92B can be suitably performed.

[0090] In the energy storage device 1 according to this embodiment, the cover corner 101C and the outer casing corner 90C have a curved shape that is convex outward when viewed from the Z-axis direction. This improves the adhesion between the cover corner 101C and the outer casing corner 90C, and prevents damage to the outer casing corner 90C when the cover corner 101C is brought into close contact with the outer casing corner 90C.

[0091] In the energy storage device manufacturing method according to this embodiment, the cover member 101 may be prepared in step S101 by integrally forming the main body portion 101M and the cover flange portion 101F by injection molding. In this case, the main body portion 101M and the cover flange portion 101F can be easily constructed from the same material.

[0092] In the energy storage device manufacturing method according to this embodiment, in step S101, a cover member 101 including the main body 101M and the cover flange portion 101F, which are integrated with each other, may be prepared by insert molding the cover flange portion 101F into the main body portion 101M. In this case, for example, a cover member 101 including the highly rigid cover flange portion 101F can be easily formed using a resin to which a filler has been added.

[0093] In the energy storage device manufacturing method according to this embodiment, in step S101, a cover member 101 including the main body 101M and the cover flange 101F, which are integrated with each other, may be prepared by welding the cover flange 101F to the main body 101M. In this case, for example, by constructing the cover flange 101F with a resin that does not contain fillers, the sealing performance when the cover flange 101F is welded to the first flange 92A and the second flange 92B can be improved.

[0094] In the energy storage device manufacturing method according to this embodiment, in step S101, the main body portion 101M and the cover flange portion 101F may be formed by two-color molding to prepare a cover member 101 including the main body portion 101M and the cover flange portion 101F which are integrated with each other. In this case, for example, by constructing the cover flange portion 101F with a resin that does not contain fillers, the sealing performance when the cover flange portion 101F is welded to the first flange portion 92A and the second flange portion 92B can be improved.

[0095] The above embodiments illustrate one aspect of the present invention. Therefore, the present invention is not limited to the above embodiments and can be modified as desired.

[0096] For example, in the above embodiment, an example was described in which the first outer pack 90A and the second outer pack 90B each have recesses as housing portions for housing the energy storage module 1A and the cover member 101, that is, an example in which the first outer pack 90A has a first recess 91A and the second outer pack 90B has a second recess 91B. However, for example, the first outer pack 90A may have a first recess 91A and the second outer pack 90B may be formed flat so that the first recess 91A of the first outer pack 90A is closed by the flat portion of the second outer pack 90B.

[0097] In this case, the first housing portion of the first outer pack 90A is the first recess 91A, and the second housing portion of the second outer pack 90B is the flat portion of the second outer pack 90B that overlaps with the first recess 91A. In this case, the second flange portion 92B of the second outer pack 90B can be defined as the portion of the second outer pack 90B that is outside the flat portion that overlaps with the first recess 91A. In this case, of the first outer pack 90A and the second outer pack 90B, only the first outer pack 90A may have an outer corner portion 90C when viewed from the Z-axis direction. Also in this case, the joining position of the first flange portion 92A and the second flange portion 92B in the Z-axis direction is on one end side of the cover member 101 in the Z-axis direction. For this reason, in this case, the cover flange portion 101F may be provided at one end of the main body portion 101M in the Z-axis direction.

[0098] Furthermore, in the above embodiment, an example was described in which the cover flange portion 101F is provided only at the cover corner portion 101C, thereby forming an L-shaped plate extending from the side wall 112 to the side wall 114 when viewed from the Z-axis direction. However, the cover flange portion 101F may be provided not only at the cover corner portion 101C but also at other parts of the side wall 112. For example, the cover flange portion 101F may be provided over the entire side wall 112.

[0099] The energy storage device described in the appendix is ​​[1] "an energy storage device comprising: an energy storage module including a plurality of electrodes stacked along a first direction; a cover member arranged adjacent to the energy storage module when viewed from the first direction; and an outer casing housing the energy storage module and the cover member, wherein the outer casing includes a housing portion housing the energy storage module and the cover member, and an outer flange portion surrounding the housing portion when viewed from the first direction; the cover member includes a main body portion and a cover flange portion provided on the main body portion, and the cover flange portion is joined to the outer flange portion."

[0100] The energy storage device described in the appendix may be [2] "the energy storage device described in [1] above, wherein the outer casing has a first outer casing and a second outer casing arranged to sandwich the energy storage module and the cover member from both sides in the first direction, the first outer casing includes a first housing portion for housing the energy storage module and the cover member and a first outer flange portion that surrounds the first housing portion when viewed from the first direction, the second outer casing includes a second housing portion for housing the energy storage module and the cover member and a second outer flange portion that surrounds the second housing portion when viewed from the first direction, the housing portion includes the first housing portion and the second housing portion, the outer flange portion includes the first outer flange portion and the second outer flange portion, and the cover flange portion is sandwiched between the first outer flange portion and the second outer flange portion and joined to the first outer flange portion and the second outer flange portion."

[0101] The energy storage device described in the appendix may also be [3] "the energy storage device described in [2] above, wherein the first exterior body and the second exterior body are bonded together by the first exterior flange portion and the second exterior flange portion overlapping and joining them, the main body portion has a cover corner portion which is a corner portion facing the opposite side from the energy storage module when viewed from the first direction, the cover flange portion is provided at least on the cover corner portion such that it protrudes outward from the main body portion when viewed from the first direction, and the cover corner portion is sandwiched between the first exterior flange portion and the second exterior flange portion and joined to the first exterior flange portion and the second exterior flange portion when the cover corner portion is in contact with the exterior corner portion which is at least one corner portion of the first housing portion and the second housing portion."

[0102] The energy storage device described in the appendix may also be [4] "the energy storage device according to any one of [1] to [3] above, wherein the main body comprises a resin and a filler added to the resin having a coefficient of linear expansion smaller than the coefficient of linear expansion of the resin."

[0103] The energy storage device described in the appendix may also be the energy storage device described in [4] above, wherein the amount of filler added to the cover flange portion is smaller than the amount of filler added to the main body portion.

[0104] The energy storage device described in the appendix may be [6] "the energy storage device described in any of [1] to [5] above, wherein the exterior flange portion is made of a laminated member comprising a metal layer and a resin layer laminated on the metal layer, and the resin layers are stacked so as to be in contact with each other, and the cover flange portion contains a resin compatible with the resin layer of the laminated member."

[0105] The energy storage device described in the appendix may be [7] "the energy storage device described in [3] above, wherein the corners of the cover and the corners of the exterior have a curved shape that is convex outward when viewed from the first direction."

[0106] The energy storage device described in the appendix may also be the energy storage device described in [3] or [7] above, wherein the first housing and the second housing are recesses for housing the energy storage module and the cover member, and the cover corners are the corners of the first housing and the second housing which are recesses.

[0107] The method for manufacturing an energy storage device as described in the appendix may be [9] "a method for manufacturing an energy storage device comprising: an energy storage module including a plurality of electrodes stacked along a first direction; a cover member having a main body portion and a cover flange portion provided on the main body portion; and an exterior body for housing the energy storage module and the cover member, comprising: a first step of preparing the cover member; and a second step after the first step of housing the energy storage module and the cover member in the exterior body and joining the cover member and the exterior body, wherein the exterior body includes a housing portion and an exterior flange portion that surrounds the housing portion when viewed from the first direction, and in the second step, housing the energy storage module and the cover in the housing portion and joining the cover flange portion to the exterior flange portion."

[0108] The method for manufacturing an energy storage device as described in the appendix may be

[10] "the method for manufacturing an energy storage device as described in [9] above, wherein in the first step, the cover member is prepared by integrally forming the main body portion and the cover flange portion by injection molding."

[0109] The method for manufacturing an energy storage device as described in the appendix may also be

[11] "the method for manufacturing an energy storage device as described in [9] above, wherein in the first step, the cover member is prepared by insert molding the cover flange portion onto the main body portion, thereby integrating the main body portion and the cover flange portion with each other."

[0110] The method for manufacturing an energy storage device as described in the appendix may also be

[12] "the method for manufacturing an energy storage device as described in [9] above, wherein in the first step, the cover flange portion is welded to the main body portion to prepare the cover member including the main body portion and the cover flange portion which are integrated with each other."

[0111] The method for manufacturing an energy storage device as described in the appendix may be

[13] "the method for manufacturing an energy storage device as described in [9] above, wherein in the first step, the main body portion and the cover flange portion are formed by two-color molding to prepare the cover member including the main body portion and the cover flange portion which are integrated with each other." [Explanation of symbols]

[0112] 1...Energy storage device, 1A...Energy storage module, 90...Outer pack (outer body), 90A...First outer pack (first outer body), 90B...Second outer pack (second outer body), 90C...Outer corner, 91A...First recess (first housing section), 91B...Second recess (second housing section), 92A...First flange section (first outer flange section), 92B...Second flange section (second outer flange section), 100,101...Cover member, 101M...Main body section, 101F...Cover flange section, 101C...Cover corner.

Claims

1. A power storage module including multiple electrodes stacked along a first direction, A cover member arranged adjacent to the energy storage module when viewed from the first direction, An outer casing housing the energy storage module and the cover member, Equipped with, The exterior body includes a housing portion for housing the energy storage module and the cover member, and an exterior flange portion that surrounds the housing portion when viewed from the first direction. The cover member includes a main body and a cover flange portion provided on the main body, The cover flange portion is joined to the exterior flange portion. Energy storage device.

2. The exterior body comprises a first exterior body and a second exterior body arranged to sandwich the energy storage module and the cover member from both sides in the first direction. The first exterior body includes a first housing portion for housing the energy storage module and the cover member, and a first exterior flange portion that surrounds the first housing portion when viewed from the first direction. The second exterior body includes a second housing portion for housing the energy storage module and the cover member, and a second exterior flange portion that surrounds the second housing portion when viewed from the first direction. The housing section includes the first housing section and the second housing section, The exterior flange portion includes the first exterior flange portion and the second exterior flange portion. The cover flange portion is sandwiched between the first exterior flange portion and the second exterior flange portion and joined to the first exterior flange portion and the second exterior flange portion. The energy storage device according to claim 1.

3. The first exterior body and the second exterior body are bonded together by overlapping and joining the first exterior flange portion and the second exterior flange portion. The main body portion has a cover corner portion which is a corner portion facing the opposite side from the energy storage module when viewed from the first direction, The cover flange portion is provided at least on the cover corner portion such that it protrudes outward from the main body portion when viewed from the first direction, and is joined to the first exterior flange portion and the second exterior flange portion by being sandwiched between the first exterior flange portion and the second exterior flange portion when the cover corner portion is in contact with the exterior corner portion which is at least one corner of the first housing portion and the second housing portion. The energy storage device according to claim 2.

4. The main body comprises a resin and a filler added to the resin having a coefficient of linear expansion smaller than that of the resin. The energy storage device according to claim 1.

5. The amount of filler added to the cover flange portion is smaller than the amount of filler added to the main body portion. The energy storage device according to claim 4.

6. The exterior flange portion is composed of a laminated member including a metal layer and a resin layer laminated on the metal layer, and the resin layers are stacked so that they are in contact with each other. The cover flange portion contains a resin compatible with the resin layer of the laminate member. The energy storage device according to claim 1.

7. The corners of the cover and the corners of the exterior have a curved shape that is convex outward when viewed from the first direction. The energy storage device according to claim 3.

8. The first and second housing sections are recesses for housing the energy storage module and the cover member, The cover corner is the corner of the first and second housing portions, which are recesses. The energy storage device according to claim 3 or 7.

9. A method for manufacturing an energy storage device comprising: an energy storage module including a plurality of electrodes stacked along a first direction; a cover member having a main body and a cover flange portion provided on the main body; and an outer casing for housing the energy storage module and the cover member, The first step is to prepare the cover member, Following the first step, a second step is performed in which the energy storage module and the cover member are housed in the outer casing, and the cover member and the outer casing are joined together. Equipped with, The exterior body includes a housing portion and an exterior flange portion that surrounds the housing portion when viewed from the first direction, In the second step, the energy storage module and the cover are housed in the housing, and the cover flange is joined to the exterior flange. A method for manufacturing a power storage device.

10. In the first step described above, the cover member is prepared by integrally forming the main body portion and the cover flange portion by injection molding. A method for manufacturing an energy storage device according to claim 9.

11. In the first step, the cover member is prepared by insert molding the cover flange portion onto the main body portion, thereby integrating the main body portion and the cover flange portion together. A method for manufacturing an energy storage device according to claim 9.

12. In the first step, the cover member is prepared by welding the cover flange portion to the main body portion, thereby integrating the main body portion and the cover flange portion together. A method for manufacturing an energy storage device according to claim 9.

13. In the first step, the main body portion and the cover flange portion are formed by two-color molding to prepare the cover member including the main body portion and the cover flange portion which are integrated with each other. A method for manufacturing an energy storage device according to claim 9.

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