Power storage device, exterior film, and method for manufacturing power storage device

Abstract

This electric power storage device comprises an electrode body and an exterior body that seals the electrode body. The exterior body has: an exterior film that wraps the electrode body; and a lid body that seals the electrode body together with the exterior film. The exterior film includes a barrier layer including a metal material. The lid body includes a portion including a metal material. The barrier layer of the exterior film and the portion including the metal material of the lid body are directly bonded to each other.

Description

Electricity storage device, exterior film, and method for manufacturing an electricity storage device

[0001] The present invention relates to an electricity storage device, an exterior film, and a method for manufacturing an electricity storage device.

[0002] Patent Document 1 discloses an example of an electricity storage device. This electricity storage device includes an electrode assembly and an exterior body that seals the electrode assembly. The exterior body includes an exterior film that encases the electrode assembly and a lid that is joined to the exterior film. The exterior film and the lid are joined by heat sealing.

[0003] Japanese Patent Application Laid-Open No. 2022-123686

[0004] In the above-mentioned electricity storage device, there is a risk that moisture may penetrate into the interior of the exterior body through the gap between the exterior film and the lid. Therefore, there is still room for improvement in the moisture barrier properties of the above-mentioned electricity storage device.

[0005] An object of the present invention is to provide an electricity storage device with high moisture barrier properties, an exterior film used in the electricity storage device, and a method for manufacturing the electricity storage device.

[0006] The energy storage device according to a first aspect of the present invention comprises an electrode body and an exterior body that seals the electrode body, the exterior body having an exterior film that wraps the electrode body and a lid that seals the electrode body together with the exterior film, the exterior film including a barrier layer that contains a metal material, the lid body including a portion that contains a metal material, and the barrier layer of the exterior film and the portion of the lid body that contains a metal material are directly bonded to each other.

[0007] The electric storage device according to a second aspect of the present invention is the electric storage device according to the first aspect, wherein the portion of the exterior film that is joined to the portion of the lid body that contains the metal material is a single layer of the barrier layer.

[0008] The energy storage device according to a third aspect of the present invention is the energy storage device according to the first aspect, wherein the exterior film includes another layer laminated on the barrier layer, and the portion of the exterior film that is joined to the portion of the lid body that includes the metal material is a portion where the barrier layer is partially exposed from the other layer.

[0009] A fourth aspect of the present invention is an energy storage device according to any one of the first to third aspects, wherein the lid body has a covering body and a lid main body joined to the covering body, at least one of the covering body and the lid main body being composed of a metal material, the exterior body has a sealing portion in which the exterior film is sandwiched between the covering body and the lid main body, and the barrier layer of the exterior film is directly joined to the portions of the covering body and the lid main body composed of a metal material at the sealing portion.

[0010] An exterior film according to a fifth aspect of the present invention is an exterior film used as an exterior body for an electricity storage device, wherein the exterior body has a lid body comprising a metal material, the exterior film includes a barrier layer comprising a metal material, and the portion of the lid body that is joined to the portion comprising the metal material is a single layer of the barrier layer, or the barrier layer is partially exposed from another layer.

[0011] A sixth aspect of the present invention relates to a method for manufacturing an electricity storage device, the method comprising: directly joining the barrier layer of the exterior film and the portion of the lid that contains the metal material;

[0012] The electricity storage device, exterior film, and method for manufacturing an electricity storage device according to the present invention have high moisture barrier properties.

[0013] 4A is a perspective view of an electricity storage device according to an embodiment. FIG. 4B is a cross-sectional view showing an example of the layer structure of an exterior film included in the electricity storage device of FIG. 1. FIG. 4A is a view of the exterior film included in the electricity storage device of FIG. 1 in an unfolded state. FIG. 4B is a cross-sectional view of a cover included in the electricity storage device of FIG. 1. FIG. 4A is a cross-sectional view taken along line D4B-D4B in FIG. 4A. FIG. 4B is a perspective view of a lid main body included in the electricity storage device of FIG. 1. FIG. 4B is a front view of the electricity storage device of FIG. 1. FIG. 4C is a cross-sectional view taken along line D7-D7 in FIG. 1. FIG. 4D is a flowchart showing an example of a method for manufacturing the electricity storage device of FIG. 1. FIG. 4A is a cross-sectional view of an electricity storage device according to a first modified example. FIG. 4B is a cross-sectional view of an electricity storage device according to a second modified example. FIG. 4C is a cross-sectional view of an electricity storage device according to a third modified example. FIG. 4D is a cross-sectional view of an electricity storage device according to another example of the third modified example. FIG. 4D is a cross-sectional view showing an example of the layer structure of an exterior film 50 included in an electricity storage device according to a fourth modified example.

[0014] Hereinafter, an electricity storage device according to an embodiment of the present invention will be described with reference to the drawings. In this specification, a numerical range indicated by "to" means "greater than or equal to" or "less than or equal to." For example, the expression "2 to 15 mm" means 2 mm or more and 15 mm or less.

[0015] 1. Embodiments 1-1. Configuration of Electricity Storage Device FIG. 1 is a perspective view that schematically illustrates an electricity storage device 10 according to an embodiment. FIG. 2 is a cross-sectional view that illustrates an example of the layer configuration of an exterior film 50 included in the electricity storage device 10 of FIG. 1. FIG. 3 is a view of the exterior film 50 included in the electricity storage device 10 of FIG. 1 in an unfolded state. FIG. 4A is a perspective view of a covering body 70 included in the electricity storage device 10 of FIG. 1. FIG. 4B is a cross-sectional view taken along line D4B-D4B in FIG. 4A. FIG. 5 is a perspective view of a lid main body 80 included in the electricity storage device 10 of FIG. 1. FIG. 6 is a front view of the electricity storage device 10 of FIG. 1. FIG. 7 is a cross-sectional view taken along line D7-D7 in FIG. 1. In FIG. 1, the direction of arrow UD indicates the thickness direction of the electricity storage device 10, the direction of arrow LR indicates the width direction of the electricity storage device 10, and the direction of arrow FB indicates the depth direction of the electricity storage device 10. The directions indicated by the arrows UDLRFB are the same in the subsequent drawings.

[0016] The energy storage device 10 includes an electrode assembly 20 including a current collector 30 (see FIG. 7 ) and an exterior body 40. The electrode assembly 20 includes electrodes (positive and negative electrodes) constituting an energy storage member such as a lithium-ion battery, capacitor, all-solid-state battery, semi-solid battery, quasi-solid battery, polymer battery, all-resin battery, lead-acid battery, nickel-metal hydride battery, nickel-cadmium battery, nickel-iron battery, nickel-zinc battery, silver oxide-zinc battery, metal-air battery, polyvalent cation battery, or capacitor, as well as a separator. In this embodiment, the electrode assembly 20 has a substantially rectangular parallelepiped shape. Note that the term "substantially rectangular parallelepiped" includes not only a perfect rectangular parallelepiped, but also a solid that can be considered a rectangular parallelepiped by modifying the shape of a portion of its outer surface, for example. The electrode assembly 20 may have a cylindrical or polygonal prism shape, for example.

[0017] The exterior body 40 seals the electrode body 20. The exterior body 40 includes an exterior film 50 and a lid body 60. In the present embodiment, the exterior film 50 is wrapped around the electrode body 20. The electrode body 20 may be housed inside the exterior film 50, which is configured in a cylindrical shape. The exterior body 40 has a pair of first surfaces 41A, 41B and a pair of second surfaces 42A, 42B. In the present embodiment, the pair of first surfaces 41A, 41B are substantially the same size. In the present embodiment, the pair of second surfaces 42A, 42B are substantially the same size. The pair of first surfaces 41A, 41B have a larger area than the pair of second surfaces 42A, 42B. The pair of lid bodies 60 are respectively arranged on the sides of the electrode body 20.

[0018] For example, there is a method of forming a recess in the exterior film 50 through cold forming to accommodate the electrode assembly 20. However, it is not necessarily easy to form a deep recess using this method. Attempting to form a deep recess (e.g., a forming depth of 15 mm) by cold forming increases the likelihood of pinholes or cracks occurring in the exterior film 50, resulting in a decrease in battery performance. On the other hand, the exterior body 40 seals the electrode assembly 20 by wrapping the exterior film 50 around the electrode assembly 20, and therefore can easily seal the electrode assembly 20 regardless of the thickness of the electrode assembly 20. Note that in order to reduce the dead space between the electrode assembly 20 and the exterior film 50 and improve the volumetric energy density of the power storage device 10, it is preferable that the exterior film 50 be wrapped so as to contact the outer surface of the electrode assembly 20. Furthermore, in all-solid-state batteries, it is necessary to apply a high pressure uniformly from the outer surface of the battery to maximize battery performance, so it is necessary to eliminate the space between the electrode assembly 20 and the exterior film 50. Therefore, it is preferable that the exterior film 50 be wrapped so as to contact the outer surface of the electrode assembly 20.

[0019] As shown in FIG. 2 , the exterior film 50 is a laminate (laminate film) having, for example, a base material layer 51, a barrier layer 52, and a heat-sealable resin layer 53 in this order. It is not necessary for the exterior film 50 to include all of these layers; it is sufficient for it to include at least the barrier layer 52. That is, the exterior film 50 is only required to be made of a flexible and easily bendable material, and may be made of, for example, a resin film. It is preferable that the exterior film 50 is heat-sealable. The innermost and outermost layers of the exterior film 50 may be the heat-sealable resin layers 53. In this case, the exterior film 50 may encase the electrode body 20 and the lid body 60 by joining the outermost and innermost layers.

[0020] The overall thickness of the exterior film 50 can be selected arbitrarily. From the viewpoint of strength, the thickness of the exterior film 50 is preferably 50 μm or more. From the viewpoint of formability or conformability, the thickness of the exterior film 50 is preferably 1200 μm or less. The thickness of the exterior film 50 is preferably within the range of 50 μm or more and 1200 μm or less.

[0021] The substrate layer 51 included in the exterior film 50 is a layer that imparts heat resistance to the exterior film 50 and suppresses the occurrence of pinholes that may occur during processing or distribution. The substrate layer 51 is composed of, for example, at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer. For example, by including at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer in the substrate layer 51, the barrier layer 52 can be protected during processing of the exterior film 50 and breakage of the exterior film 50 can be suppressed. Furthermore, from the viewpoint of increasing the tensile elongation of the exterior film 50, the stretched polyester resin layer is preferably a biaxially stretched polyester resin layer, and the stretched polyamide resin layer is preferably a biaxially stretched polyamide resin layer. Furthermore, from the viewpoint of excellent puncture strength or impact strength, the stretched polyester resin layer is more preferably a biaxially stretched polyethylene terephthalate (PET) film, and the stretched polyamide resin layer is more preferably a biaxially stretched nylon (ONy) film. The substrate layer 51 may be composed of both a stretched polyester resin layer and a stretched polyamide resin layer. The thickness of the substrate layer 51 is preferably, for example, 5 to 300 μm, and more preferably 5 to 150 μm, from the viewpoint of film strength.

[0022] The barrier layer 52 is a layer that prevents at least moisture penetration. The barrier layer 52 is bonded to the substrate layer 51 via, for example, an adhesive layer 54. Examples of the barrier layer 52 include metal foils, vapor-deposited films, and resin layers with barrier properties. Vapor-deposited films include metal vapor-deposited films, inorganic oxide vapor-deposited films, and carbon-containing inorganic oxide vapor-deposited films. Resin layers include fluorine-containing resins such as polyvinylidene chloride, polymers based on chlorotrifluoroethylene (CTFE), polymers based on tetrafluoroethylene (TFE), polymers having fluoroalkyl groups, and polymers based on fluoroalkyl units, as well as ethylene-vinyl alcohol copolymers. The barrier layer 52 may also be a resin film having at least one of these vapor-deposited films and resin layers. The barrier layer 52 may be formed of multiple layers. In this embodiment, the barrier layer 52 includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 52 include aluminum alloys, stainless steel, titanium steel, and steel plates. When used as a metal foil, it is preferable that the metal material contains at least one of an aluminum alloy foil and a stainless steel foil.

[0023] In the barrier layer 52, the layer made of the aforementioned metal material may contain recycled metal material. Examples of recycled metal material include recycled aluminum alloy, stainless steel, titanium steel, and steel plate. These recycled materials can be obtained by known methods. Recycled aluminum alloy material can be obtained, for example, by the manufacturing method described in International Publication No. 2022 / 092231. The barrier layer 52 may be made of recycled material alone, or may be made of a mixture of recycled and virgin material. Note that recycled metal material refers to metal material that has been made reusable by collecting, isolating, and refining various products used in the market or waste from manufacturing processes. Furthermore, virgin metal material refers to new metal material refined from natural metal resources (raw materials) and is not recycled material.

[0024] From the viewpoint of improving the formability or conformability of the exterior film 50, the aluminum alloy foil is preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy. From the viewpoint of further improving the formability or conformability, an iron-containing aluminum alloy foil is preferred. In the iron-containing aluminum alloy foil (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass. By having an iron content of 0.1% by mass or more, an exterior film 50 with better formability can be obtained. By having an iron content of 9.0% by mass or less, an exterior film 50 with better flexibility can be obtained. Furthermore, silicon, magnesium, copper, manganese, etc. may be added as necessary. Furthermore, softening can be achieved by annealing or the like. From the viewpoint of improving the mechanical strength of the exterior film 50, the aluminum alloy foil is more preferably a hard aluminum alloy foil made of, for example, a work-hardened aluminum alloy. Examples of hard aluminum alloy foils include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-H18, JIS H4160:1994 A8079H-H18, JIS H4000:2014 A8021P-H14, or JIS H4000:2014 A8079P-H14. From the viewpoint of improving the mechanical strength of the exterior film 50, the aluminum alloy foil is preferably an aluminum alloy foil containing magnesium. In the aluminum alloy foil containing magnesium (100% by mass), the magnesium content is preferably 0.2 to 5.6% by mass, and more preferably 0.2 to 3.0% by mass. Examples of aluminum alloy foils containing magnesium include aluminum alloy foils having compositions defined in JIS H4000:2017 A5005P-O, JIS H4000:2017 A5050P-O, and JIS H4000:2017 A5052P-O.

[0025] Examples of the stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. Furthermore, from the viewpoint of providing an exterior film 50 with excellent formability, the stainless steel foil is preferably made of austenitic stainless steel.

[0026] Specific examples of austenitic stainless steels that form the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

[0027] In the case of a metal foil, the thickness of the barrier layer 52 should be sufficient to at least function as a barrier layer that prevents moisture penetration, and may be, for example, about 5 to 1000 μm. The thickness of the barrier layer 52 is preferably about 85 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, and particularly preferably about 35 μm or less. The thickness of the barrier layer 52 is preferably about 9.0 μm or more, more preferably about 20 μm or more, and more preferably about 25 μm or more. Preferred ranges for the thickness of the barrier layer 52 include about 9.0 to 1000 μm, about 9.0 to 1000 μm, about 9.0 to 1000 μm, about 9.0 to 1000 μm, about 9.0 to 85 μm, about 9.0 to 50 μm, about 9.0 to 40 μm, about 9.0 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 52 is made of aluminum alloy foil, the above-mentioned ranges are particularly preferred. From the viewpoint of imparting high formability and high rigidity to the exterior film 50, the thickness of the barrier layer 52 is preferably about 35 μm or more, more preferably about 45 μm or more, even more preferably about 50 μm or more, and even more preferably about 55 μm or more, and is preferably about 200 μm or less, more preferably about 85 μm or less, even more preferably about 75 μm or less, and even more preferably about 70 μm or less. Preferred ranges are approximately 35 to 200 μm, approximately 35 to 85 μm, approximately 35 to 75 μm, approximately 35 to 70 μm, approximately 45 to 200 μm, approximately 45 to 85 μm, approximately 45 to 75 μm, approximately 45 to 70 μm, approximately 50 to 200 μm, approximately 50 to 85 μm, approximately 50 to 75 μm, approximately 50 to 70 μm, approximately 55 to 200 μm, approximately 55 to 85 μm, approximately 55 to 75 μm, and approximately 55 to 70 μm. The high formability of the exterior film 50 facilitates deep drawing, which can contribute to increasing the capacity of the electricity storage device. Furthermore, while increasing the capacity of the electricity storage device increases the weight of the electricity storage device, increasing the rigidity of the exterior film 50 can contribute to high sealing performance of the electricity storage device.In particular, when the barrier layer 52 is made of stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less. The thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. Preferred ranges for the thickness of the stainless steel foil include about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

[0028] Furthermore, when the barrier layer 52 is an aluminum foil, it is preferable that a corrosion-resistant coating be provided on at least the surface opposite the substrate layer 51 to prevent dissolution and corrosion. The barrier layer 52 may be provided with a corrosion-resistant coating on both sides. Here, the corrosion-resistant coating refers to a thin film that is provided with corrosion resistance (e.g., acid resistance, alkali resistance, etc.) by performing, for example, a hydrothermal conversion treatment such as boehmite treatment, a chemical conversion treatment, an anodizing treatment, a plating treatment of nickel or chromium, or a corrosion prevention treatment such as applying a coating agent on the surface of the barrier layer 52. Specifically, the corrosion-resistant coating refers to a coating that improves the acid resistance of the barrier layer 52 (acid-resistant coating), a coating that improves the alkali resistance of the barrier layer 52 (alkali-resistant coating), or the like. The corrosion-resistant coating may be formed by one type of treatment or a combination of two or more types. Furthermore, the barrier layer 52 may be formed not only as a single layer but also as a multi-layer. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the surface of the metal foil is dissolved with a treatment agent to form a metal compound with excellent corrosion resistance. Note that these treatments may also be included in the definition of chemical conversion treatment. Furthermore, if the barrier layer 52 has a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer 52.

[0029] The corrosion-resistant coating prevents delamination between the barrier layer 52 (e.g., aluminum alloy foil) and the substrate layer 51 during molding of the exterior film 50, prevents dissolution and corrosion of the surface of the barrier layer 52 due to hydrogen fluoride produced by a reaction between an electrolyte and water, and in particular prevents dissolution and corrosion of aluminum oxide present on the surface of the barrier layer 52 when the barrier layer 52 is an aluminum alloy foil, and also improves the adhesion (wettability) of the surface of the barrier layer 52, thereby preventing delamination between the substrate layer 51 and the barrier layer 52 during heat sealing and between the substrate layer 51 and the barrier layer 52 during molding.

[0030] The heat-sealable resin layer 53 is bonded to the barrier layer 52 via, for example, an adhesive layer 55. The heat-sealable resin layer 53 included in the exterior film 50 is a layer that provides heat-sealing properties to the exterior film 50. Examples of the heat-sealable resin layer 53 include resin films made of polyester resins such as polyethylene terephthalate resins and polybutylene terephthalate resins, polyolefin resins such as polyethylene resins and polypropylene resins, or acid-modified polyolefin resins obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. From the standpoints of sealability and strength, the thickness of the heat-sealable resin layer 53 is preferably, for example, 20 to 300 μm, and more preferably 40 to 150 μm.

[0031] The exterior film 50 preferably has one or more layers having a buffer function (hereinafter referred to as "buffer layer") outside the heat-sealable resin layer 53, more preferably outside the barrier layer 52. The buffer layer may be laminated on the outside of the base material layer 51, or the base material layer 51 may also function as a buffer layer. When the exterior film 50 has multiple buffer layers, the multiple buffer layers may be adjacent to each other, or may be laminated with the base material layer 51, the barrier layer 52, or the like interposed therebetween.

[0032] The material constituting the buffer layer can be arbitrarily selected from materials having cushioning properties. Examples of the material having cushioning properties include rubber, nonwoven fabric, and foam sheet. Examples of rubber include natural rubber, fluororubber, and silicone rubber. The rubber hardness is preferably about 20 to 90. The material constituting the nonwoven fabric is preferably a material having excellent heat resistance. When the buffer layer is made of nonwoven fabric, the lower limit of the thickness of the buffer layer is preferably 100 μm, more preferably 200 μm, and even more preferably 1000 μm. When the buffer layer is made of nonwoven fabric, the upper limit of the thickness of the buffer layer is preferably 5000 μm, and even more preferably 3000 μm. The thickness of the buffer layer is preferably in the range of 100 μm to 5000 μm, 100 μm to 3000 μm, 200 μm to 5000 μm, 200 μm to 3000 μm, 1000 μm to 5000 μm, or 1000 μm to 3000 μm, with the most preferred range being 1000 μm to 3000 μm.

[0033] When the buffer layer is made of rubber, the lower limit of the thickness of the buffer layer is preferably 0.5 mm. When the buffer layer is made of rubber, the upper limit of the thickness of the buffer layer is preferably 10 mm, more preferably 5 mm, and even more preferably 2 mm. When the buffer layer is made of rubber, the preferred range of the thickness of the buffer layer is 0.5 mm to 10 mm, 0.5 mm to 5 mm, or 0.5 mm to 2 mm.

[0034] When the exterior film 50 has a buffer layer, the buffer layer functions as a cushion, thereby preventing the exterior film 50 from being damaged by impact when the energy storage device 10 is dropped or by handling during manufacturing of the energy storage device 10.

[0035] The lid body 60 has a cover body 70 and a lid main body 80 .

[0036] The coating 70 shown in FIG. 4 has a shape similar to a hollow rectangular parallelepiped, for example. A space 79 is formed inside the coating 70. The material constituting the coating 70 can be selected arbitrarily. From the viewpoint of suitably forming the second sealing portion 92 (described later), the coating 70 preferably contains a metallic material. Here, "containing a metallic material" means that, when the entire material constituting the coating 70 is taken as 100 mass%, the metallic material content is 50 mass% or more, preferably 80 mass% or more, more preferably 90 mass% or more, and even more preferably 95 mass% or more. In other words, the material constituting the coating 70 can contain materials other than metallic materials in addition to metallic materials. The metallic material constituting the coating 70 can be selected arbitrarily. The metallic material constituting the coating 70 can be, for example, aluminum, an aluminum alloy, nickel, copper, or a copper alloy. For example, when the electrode body 20 is a lithium-ion battery, the coating 70 connected to the positive electrode is preferably made of aluminum or an aluminum alloy. The coating 70 connected to the negative electrode is preferably made of nickel, copper, or a copper alloy. The material constituting the coating 70 connected to the negative electrode may be copper plated with nickel. The material constituting the coating 70 may contain recycled metal materials. In this embodiment, the coating 70 is made only of a metal material. Since the coating 70 contains a metal material, it also functions as an electrode terminal. This simplifies the configuration of the electricity storage device 10. When the coating 70 contains a metal material, it is preferable that the coating 70 has the corrosion-resistant coating described for the barrier layer 52.

[0037] In another example, the coating 70 may be configured to include a resin material. Here, "configured to include a resin material" means that, when the entire material constituting the coating 70 is taken as 100% by mass, the content of the resin material is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. In other words, the material constituting the coating 70 can contain materials other than the resin material in addition to the resin material.

[0038] Specific examples of resins include thermoplastic resins such as polyester, polyolefin, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenolic resin, as well as modified versions of these resins. The resin material may be a mixture of these resins, a copolymer, or a modified copolymer. Among these, the resin material is preferably a heat-sealable resin such as polyester or polyolefin, and more preferably polyolefin. When the resin material is a resin, the joining portion 80B may be molded by any molding method.

[0039] The resin material contained in the material constituting the coating 70 is preferably an olefin-based random copolymer, more preferably a resin containing a polyolefin skeleton as a main component, even more preferably a polyolefin as a main component, and even more preferably a polypropylene as a main component. The polyolefin may be an acid-modified polyolefin. The resin material contained in the material constituting the coating 70 preferably contains multiple types of amide-based lubricants. Furthermore, the resin material contained in the material constituting the coating 70 preferably contains multiple types of amide-based lubricants that further contain unsaturated fatty acid amides in addition to saturated fatty acid amides. The resin material contained in the material constituting the coating 70 may be a polyolefin resin to which a propylene-based elastomer having a melting point higher than 150°C has been added.

[0040] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters. Examples of copolymer polyesters include copolymer polyesters whose repeating units are primarily ethylene terephthalate. Specific examples include copolymer polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), and polyethylene (terephthalate / decanedicarboxylate). Among these, polybutylene terephthalate is preferred as the resin material from the viewpoint of enhancing heat resistance and pressure resistance.

[0041] Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylenes such as homopolypropylene, polypropylene block copolymers (e.g., block copolymers of propylene and ethylene), and polypropylene random copolymers (e.g., random copolymers of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. Among these, polypropylene is preferred as the resin material because of its excellent heat-sealing properties and electrolyte resistance.

[0042] The resin as the resin material may contain a filler as needed. Specific examples of the filler include glass beads, graphite, glass fiber, and carbon fiber. By including the filler in the resin as the resin material, the deformation resistance of the joint 80B against temperature changes can be improved.

[0043] The melt mass flow rate of the resin material contained in the material constituting the coating 70 is preferably in the range of 1 g / 10 min to 100 g / 10 min, and more preferably in the range of 5 g / 10 min to 80 g / 10 min. The melt mass flow rate is measured in accordance with JIS K7210-1:2014. The melt mass flow rate is measured at 230°C.

[0044] The cover 70 has a first surface 70X and a second surface 70Y. The first surface 70X faces the electrode assembly 20. An opening 70Z is formed across the first surface 70X. The second surface 70Y is the surface opposite the first surface 70X. An opening 70YA is formed in the second surface 70Y, into which the lid body 80 (described later) is fitted. The opening 70YA penetrates the second surface 70Y. The shape of the opening 70YA in a front view can be selected as desired depending on the shape of the lid body 80. The shape of the opening 70YA may be a square, rectangle, a polygon with more than one side, a circle, or an ellipse. In this embodiment, the shape of the opening 70YA in a front view is rectangular. The corners of the opening 70YA are preferably rounded by performing a rounding process. When the covering body 70 is configured to include a resin material, it is preferable that an adhesive film bondable to metal materials and resin materials be bonded to at least a portion of the inner circumferential surface of the opening 70YA, from the viewpoint of suitably joining the lid body 80. In another example, when the covering body 70 is configured to include a resin material, it is preferable that at least a portion of the portion of the covering body 70 corresponding to the inner circumferential surface of the opening 70YA has a layer bondable to a metal material, from the viewpoint of suitably joining the lid body 80.

[0045] The cover 70 includes an upper portion 71, side portions 72 and 73, a lower portion 74, and a protrusion 70A. The upper portion 71 constitutes the upper surface of the lid 60. The upper portion 71 extends in a first direction (in the present embodiment, the LR direction) when viewed from the front of the lid 60. The side portions 72 and 73 are connected to the upper portion 71 and constitute the side surfaces of the lid 60. The side portions 72 and 73 extend in a second direction (in the present embodiment, the UD direction) that intersects with the first direction when viewed from the front of the lid 60. In the present embodiment, the first direction and the second direction are orthogonal when viewed from the front of the lid 60. The first direction and the second direction do not have to be orthogonal when viewed from the front of the lid 60. The lower portion 74 constitutes the lower surface of the lid 60. The lower portion 74 extends in a first direction (in the present embodiment, the LR direction) when viewed from the front of the lid 60.

[0046] The protrusions 70A protrude inward from the upper portion 71, side portions 72, 73, and lower portion 74 of the cover 70. The protrusions 70A define the portions that cover the lid body 80, in other words, the openings 70YA. The amount of protrusion of the protrusions 70A from the upper portion 71, side portions 72, 73, and lower portion 74 can be selected as desired. The greater the amount of protrusion of the protrusions 70A from the upper portion 71, side portions 72, 73, and lower portion 74, the smaller the opening area of ​​the openings 70YA. In other words, the smaller the amount of protrusion of the protrusions 70A from the upper portion 71, side portions 72, 73, and lower portion 74, the larger the opening area of ​​the openings 70YA. The protrusions 70A may be omitted from the cover 70.

[0047] The covering 70 further includes boundaries 75, 76, 77, and 78. The boundary 75 is the boundary between the upper portion 71 and the side portion 72. The boundary 76 is the boundary between the upper portion 71 and the side portion 73. The boundary 77 is the boundary between the lower portion 74 and the side portion 72. The boundary 78 is the boundary between the lower portion 74 and the side portion 73. The shapes of the boundaries 75 to 78 may be angular, or may be rounded by applying a rounding process. In this embodiment, the boundaries 75 to 78 are angular.

[0048] The lid body 80 shown in FIG. 5 is made of a metal material. The definition of "made of a metal material" and the specifications of the metal material constituting the lid body 80 are the same as those for the covering body 70. The lid body 80 may be made of a resin material. The definition of "made of a resin material" and the specifications of the resin material constituting the lid body 80 are the same as those for the covering body 70. At least one of the covering body 70 and the lid body 80 is made of a metal material. In this embodiment, the covering body 70 and the lid body 80 are made of a metal material. The lid body 80 has a first surface 81, a second surface 82, and a covering portion 83. The first surface 81 faces the electrode assembly 20. The first surface 81 is joined to an end of a current collector (not shown) of the electrode assembly 20, for example, by welding. The second surface 82 is the surface opposite the first surface 81. An electrode terminal may be connected to the second surface 82. When the lid body 80 is made of a metal material, it is preferable that the lid body 80 has a corrosion-resistant coating as described for the barrier layer 52 .

[0049] The covering portion 83 is connected to the first surface 81 and the second surface 82, and at least a portion of the covering portion 83 is covered by the cover 70. In this embodiment, the lid body 80 is fitted into the opening 70YA of the cover 70, so that the entire covering portion 83 is covered by the inner circumferential surface of the opening 70YA. When the lid body 80 is fitted into the opening 70YA of the cover 70, a portion of the covering portion 83 may be exposed from the cover 70. The lid body 80 may be fitted into the opening 70Z.

[0050] The covering portion 83 includes a first covering portion 83A, a second covering portion 83B, a third covering portion 83C, and a fourth covering portion 83D. The first covering portion 83A constitutes the upper surface of the lid main body 80. The first covering portion 83A extends in a first direction (in this embodiment, the LR direction) in a front view of the lid main body 80. The second covering portion 83B and the third covering portion 83C are connected to the first covering portion 83A and constitute the side surfaces of the lid main body 80. The second covering portion 83B and the third covering portion 83C extend in a second direction (in this embodiment, the UD direction) that intersects with the first direction in a front view of the lid main body 80. In this embodiment, the first direction and the second direction are orthogonal in a front view of the lid main body 80. The first direction and the second direction do not have to be orthogonal in a front view of the lid main body 80. The fourth covering portion 83D constitutes the lower surface of the lid main body 80. The fourth covering portion 83D extends in a first direction (LR direction in this embodiment) when the lid main body 80 is viewed from the front.

[0051] The covering portion 83 further includes boundaries 84, 85, 86, and 87. The boundary 84 is the boundary between the first covering portion 83A and the second covering portion 83B. The boundary 85 is the boundary between the first covering portion 83A and the third covering portion 83C. The boundary 86 is the boundary between the fourth covering portion 83D and the second covering portion 83B. The boundary 87 is the boundary between the fourth covering portion 83D and the third covering portion 83C. The shapes of the boundaries 84 to 88 may be angular, or may be rounded by applying a rounded processing. In this embodiment, the boundaries 84 to 87 are angular.

[0052] When the lid body 60 is generally plate-shaped, it is preferable that the lid body 60 have a certain thickness so that deformation of the exterior body 40 is suppressed even when the power storage device 10 is placed on top of the lid body 60. The minimum thickness of the cover 70 in the FB direction is, for example, 1.0 mm, more preferably 3.0 mm, and even more preferably 4.0 mm. The maximum thickness of the cover 70 of the lid body 60 is, for example, 20 mm, more preferably 15 mm, and even more preferably 10 mm. The maximum thickness of the cover 70 of the lid body 60 may be 20 mm or more. Preferred ranges for the thickness of the cover 70 of the lid body 60 are 1.0 mm to 20 mm, 1.0 mm to 15 mm, 1.0 mm to 10 mm, 3.0 mm to 20 mm, 3.0 mm to 15 mm, 3.0 mm to 10 mm, 4.0 mm to 20 mm, 4.0 mm to 15 mm, and 4.0 mm to 10 mm. The thickness of the cover 70 of the lid 60 may vary depending on the part of the lid 60. When the thickness of the cover 70 of the lid 60 varies depending on the part, the thickness of the cover 70 of the lid 60 is the thickness of the thickest part.

[0053] In this embodiment, the first sealed portion 91 is formed by heat-sealing the surfaces (heat-fusible resin layers 53) of the exterior film 50 that face each other.

[0054] The first sealed portion 91 includes a portion where the first edge 50A and the second edge 50B of the exterior film 50 shown in FIG. 3 are overlapped. The first sealed portion 91 extends in the longitudinal direction (FB direction) of the exterior body 40. The position where the first sealed portion 91 is formed in the exterior body 40 can be selected arbitrarily. In the present embodiment, the base 91X of the first sealed portion 91 is preferably located on the edge 43 at the boundary between the first surface 41A and the second surface 42A of the exterior body 40. The base 91X of the first sealed portion 91 may be located on any surface of the exterior body 40. From the viewpoint of configuring the energy storage device 10 compactly, it is preferable that the first sealed portion 91 be folded, for example, onto the first surface 41A or the second surface 42A of the exterior body 40 when the energy storage device 10 is in use.

[0055] In this embodiment, the second sealing portion 92 (see Figures 6 and 7) is formed by sandwiching a portion including the end of the exterior film 50 in the FB direction between the inner surface of the opening 70YA of the covering body 70 and the covering portion 83.

[0056] As shown in FIG. 7 , in the second sealing portion 92, the barrier layer 52 of the exterior film 50 and the portion of the lid 60 containing a metal material are directly bonded to each other. In this embodiment, "directly bonded" means that the barrier layer 52 of the exterior film 50 and the portion of the lid 60 containing a metal material are bonded to each other without any other element interposed therebetween. In this embodiment, the cover 70 and the lid main body 80 contain a metal material. Therefore, in the second sealing portion 92, the barrier layer 52 of the exterior film 50 is directly bonded to the cover 70 and the lid main body 80. The barrier layer 52 of the exterior film 50 and the cover 70 and the lid main body 80 are bonded to each other by, for example, metal welding. Examples of metal welding include arc welding, TIG welding, spot welding, brazing, gas welding, and laser welding. The barrier layer 52 of the exterior film 50 and the cover 70 and the lid main body 80 may also be bonded to each other by, for example, ultrasonic welding. Alternatively, the barrier layer 52 of the exterior film 50 may be directly bonded to the upper portion 71, the side portions 72, 73, and the lower portion 74 of the cover 70. In this case, the cover 70 and the lid body 80 may be bonded by metal welding, crimping, or using an adhesive. Note that, in Fig. 7, the adhesive layers 54, 55 are omitted from the illustration for the sake of simplicity.

[0057] 7 , the portion of the exterior film 50 that constitutes the second sealing portion 92, in other words, the portion of the exterior film 50 that is joined to the cover 70 and the lid main body 80, does not have the base material layer 51 and the heat-sealable resin layer 53 laminated to the barrier layer 52. In other words, the portion of the exterior film 50 that constitutes the second sealing portion 92 is a single layer of the barrier layer 52.

[0058] <1-2. Manufacturing Method of Electricity Storage Device> FIG. 8 is a flowchart showing an example of a manufacturing method of the electricity storage device 10. The manufacturing method of the electricity storage device 10 includes, for example, a first step, a second step, a third step, a fourth step, a fifth step, and a sixth step. The first step to the sixth step are performed, for example, by a manufacturing apparatus for the electricity storage device 10. At least some of the first step to the sixth step may be performed by an operator. Note that the first step to the sixth step are names of the steps in the manufacturing method of the electricity storage device 10 defined for convenience, and do not necessarily refer to the order of the steps. The order of the following steps can be changed as desired.

[0059] In the first process of step S1, the manufacturing device places a pair of lid bodies 80 on the sides of the electrode body 20 and electrically connects the electrode body 20 and the lid bodies 80 together.

[0060] The second step of step S2 is performed after the first step. In the second step, the manufacturing device wraps the electrode body 20 and the pair of lid bodies 80 with the exterior film 50.

[0061] The third step of step S3 is performed after the second step. In the third step, an edge seal portion is formed. The edge seal portion is a portion of the exterior film 50 where the first sealing portion 91 is to be formed, where a predetermined range including both ends in the LR direction is joined. The edge seal portion is folded toward the first surface 41A or the second surface 42A.

[0062] The fourth step of step S4 is performed after the third step. In the fourth step, the manufacturing apparatus fits the lid body 80 into the opening 70YA of the cover 70. By completing the fourth step, the portion of the exterior film 50 including the end in the FB direction and the end seal portion are sandwiched between the inner surface of the opening 70YA of the cover 70 and the cover portion 83 of the lid body 80.

[0063] The fifth step of step S5 is performed after the fourth step. In the fifth step, the manufacturing equipment forms the second sealing portion 92 by welding the cover 70, the lid main body 80, and the exterior film 50 together. Because the joining of the cover 70, the lid main body 80, and the exterior film 50 can be completed in a single step, the electricity storage device 10 can be easily manufactured.

[0064] The sixth step of step S6 is performed before or after the fifth step. In the sixth step, the manufacturing apparatus forms a first sealed portion 91 by heat-sealing the heat-sealable resin layer 53 in a portion including the first edge 50A of the exterior film 50 and the heat-sealable resin layer 53 in a portion including the second edge 50B.

[0065] <1-3. Functions and Effects of the Electricity Storage Device> In the electricity storage device 10, the barrier layer 52 of the exterior film 50 and the portion of the lid 60 that contains a metal material are directly joined by welding, which prevents moisture from penetrating into the interior of the exterior body 40 through the second sealing portion 92. Therefore, the electricity storage device 10 has high moisture barrier properties.

[0066] [2. Modifications] The above-described embodiments are examples of possible forms of the electricity storage device, exterior film, and method for manufacturing an electricity storage device according to the present invention, and are not intended to limit the forms. The electricity storage device, exterior film, and method for manufacturing an electricity storage device according to the present invention may take forms different from those exemplified in the embodiments. Examples include forms in which part of the configuration of the embodiments is replaced, changed, or omitted, or forms in which a new configuration is added to the embodiments. Some examples of modifications of the embodiments are shown below. Note that the following modifications can be combined with each other as long as there is no technical contradiction.

[0067] 2-1. First Modification In the above embodiment, the cover 70 may be configured to include a resin material, and the lid main body 80 may be configured to include a metal material. FIG. 9 is a cross-sectional view of the electricity storage device 10 of the first modification. In the first modification, the innermost and outermost layers of the exterior film 50 are preferably heat-sealable resin layers 53A, 53B. In a portion of the exterior film 50 that is directly bonded to the lid main body 80 in the second sealing portion 92, the innermost heat-sealable resin layer 53A is preferably partially removed. In the example shown in FIG. 9, in a portion of the exterior film 50 that is directly bonded to the lid main body 80 in the second sealing portion 92, the innermost heat-sealable resin layer 53A is partially removed, exposing the barrier layer 52. In the second sealing portion 92, the barrier layer 52 of the exterior film 50 and the lid main body 80 are joined by welding. In the second sealing portion 92, the heat-sealable resin layer 53B, which is the outermost layer of the exterior film 50, and the covering body 70 may be joined by, for example, heat sealing. The first sealing portion 91 is preferably formed by heat-sealing the heat-sealable resin layer 53A and the heat-sealable resin layer 53B together. In the fourth step, since it is not necessary to sandwich the end seal portion between the inner circumferential surface of the opening 70YA of the covering body 70 and the covering portion 83 of the lid main body 80, the electricity storage device 10 can be easily manufactured.

[0068] 2-2. Second Modification In the above embodiment, the covering 70 may be configured to include a metal material, and the lid main body 80 may be configured to include a resin material. FIG. 10 is a cross-sectional view of the power storage device 10 of the second modification. In the second modification, the innermost and outermost layers of the exterior film 50 are preferably heat-sealable resin layers 53A, 53B. In a portion of the exterior film 50 that is directly bonded to the covering 70 in the second sealing portion 92, the outermost heat-sealable resin layer 53B is partially removed, exposing the barrier layer 52. In the second sealing portion 92, the barrier layer 52 of the exterior film 50 and the covering 70 are bonded by welding. In the second sealing portion 92, the heat-sealable resin layer 53A, which is the innermost layer of the exterior film 50, and the lid main body 80 may be bonded by, for example, heat sealing.

[0069] 2-3. Third Modification In the above embodiment, the lid body 60 does not have to have the cover body 70. Fig. 11 is a cross-sectional view of the electricity storage device 10 of the third modification. In the third modification, the lid main body 80 is configured to include a metal material. In a portion of the exterior film 50 that is directly joined to the lid main body 80 in the second sealing portion 92, the heat-sealable resin layer 53 may be partially removed, exposing the barrier layer 52.

[0070] 12 is a cross-sectional view of another example of the electricity storage device 10 according to the third modification. The portion of the exterior film 50 that is directly joined to the lid body 80 in the second sealing portion 92 may be a single layer of the barrier layer 52, with the base material layer 51 and the heat-sealable resin layer 53 removed.

[0071] 2-4. Fourth Modification In the above embodiment, it is possible to change the configuration of the exterior film 50. Fig. 13 is a cross-sectional view showing an example of the layer configuration of an exterior film 50X provided in an electricity storage device 10 according to a fourth modification.

[0072] The exterior film 50X is a laminate film including a first barrier layer 510, a second barrier layer 520, and an insulating layer 530. The first barrier layer 510, the second barrier layer 520, and the insulating layer 530 are laminated so that the first barrier layer 510 and the second barrier layer 520 are not electrically connected to each other. In the fourth modification, the first barrier layer 510, the insulating layer 530, and the second barrier layer 520 are laminated in this order from the outside of the exterior body 40 toward the electrode body 20. The first barrier layer 510 and the second barrier layer 520 are composed of a metal material.

[0073] The first barrier layer 510 is bonded to the lid 60 connected to the positive electrode. From the viewpoint of increasing the bonding strength between the first barrier layer 510 and the lid 60 connected to the positive electrode, it is preferable that the metal material contained in the material constituting the first barrier layer 510 is the same metal material as the metal material contained in the material constituting the lid 60 connected to the positive electrode. The second sealing portion 92 is configured to include an end portion of the first barrier layer 510.

[0074] The second barrier layer 520 is bonded to the lid 60 connected to the negative electrode. From the viewpoint of increasing the bonding strength between the second barrier layer 520 and the lid 60 connected to the negative electrode, it is preferable that the metal material contained in the material constituting the second barrier layer 520 be the same metal material as the metal material contained in the material constituting the lid 60 connected to the negative electrode. The second sealing portion 92 is configured to include an end portion of the second barrier layer 520.

[0075] The insulating layer 530 insulates the first barrier layer 510 from the second barrier layer 520 so that they are not electrically connected to each other. Any material can be selected as the material for the insulating layer 530 as long as it can insulate the first barrier layer 510 from the second barrier layer 520. The material for the insulating layer 530 is, for example, a resin, an elastomer, or a ceramic. The ceramic is, for example, a glass, an oxide, a nitride, a carbonate, or a hydroxide. The material for the insulating layer 530 may be a combination of multiple materials. From the viewpoint of suitably insulating the first barrier layer 510 from the second barrier layer 520, it is preferable that the material for the insulating layer 530 contains an insulating filler.

[0076] The resin is, for example, a thermoplastic resin such as polyester, polyolefin, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, phenolic resin, fluororesin, or modified products of these resins. From the viewpoint of moisture barrier properties, it is preferable to use a thermoplastic resin such as a fluororesin or modified products of a fluororesin.

[0077] The ceramic is, for example, an oxide or nitride. The oxide is, for example, magnesium oxide, silicon oxide, aluminum oxide, or tin oxide. These oxides have moisture barrier properties.

[0078] The nitride is, for example, aluminum nitride, boron nitride, or silicon nitride. From the viewpoint of moisture barrier properties, it is preferable to use silicon nitride.

[0079] The carbonate is, for example, magnesium carbonate. The hydroxide is, for example, magnesium hydroxide. Magnesium carbonate and magnesium hydroxide have moisture barrier properties.

[0080] The exterior film 50 preferably includes an overlapping portion 500X, which is a portion where the first barrier layer 510, the insulating layer 530, and the second barrier layer 520 overlap in a plan view. When the exterior film 50 includes the overlapping portion 500X, even if the material constituting the insulating layer 530 does not have moisture barrier properties, the moisture barrier properties are enhanced by the first barrier layer 510 and the second barrier layer 520. In the fourth modified example, the overlapping portion 500X is formed so as to cover substantially the entire upper and lower surfaces of the electrode body 20.

[0081] The first barrier layer 510 extends in the FB direction beyond the second barrier layer 520 and the insulating layer 530 to the side of the lid 60 connected to the positive electrode.

[0082] The second barrier layer 520 extends in the FB direction to the lid body 60 side connected to the negative electrode beyond the first barrier layer 510 and the insulating layer 530. From the viewpoint of preventing a short circuit between the second barrier layer 520 and the electrode body 20, it is preferable that another insulating layer be laminated on the surface of the second barrier layer 520 opposite to the surface on which the insulating layer 530 is laminated.

[0083] From the viewpoint of suitably suppressing electrical conduction between the first barrier layer 510 and the second barrier layer 520, it is preferable that, in the FB direction, the end 530X on the lid body 60 side connected to the positive electrode of the insulating layer 530 is located closer to the lid body 60 connected to the positive electrode than the end 520X on the lid body 60 side connected to the positive electrode of the second barrier layer 520.

[0084] From the viewpoint of suitably suppressing electrical conduction between the first barrier layer 510 and the second barrier layer 520, it is preferable that, in the FB direction, the end 530Y on the lid body 60 side connected to the negative electrode of the insulating layer 530 is located closer to the lid body 60Y connected to the negative electrode than the end 510Y on the lid body 60 side connected to the negative electrode of the first barrier layer 510.

[0085] In the second modified example, the first barrier layer 510 and the second barrier layer 520 are insulated by the insulating layer 530, so that the lid body 60 connected to the positive electrode and the lid body 60 connected to the negative electrode are not electrically connected.

[0086] <2-5. Fifth Modification> In the above embodiment, the exterior film 50 of the power storage device 10 may protrude outward in the FB direction beyond one of the two lid bodies 60. The electrode body 20 is sealed by closing the portion of the exterior film 50 that protrudes outward beyond the lid body 60. The portion of the exterior film 50 that protrudes beyond the lid body 60 may be folded inward so that the outer surfaces of the exterior films 50 come into contact with each other, as in a Goebel-top container, or may be folded toward any surface of the exterior body 40, as in a brick container.

[0087] 2-6. Sixth Modification In the above embodiment, the exterior body 40 may not have one of the two lid bodies 60. In this modification, in the FB direction, in the portion of the exterior body 40 where the lid body 60 is omitted, the electrode body 20 is sealed by closing the portion of the exterior film 50 that protrudes outward beyond the electrode body 20. As in the fifth modification, the portion of the exterior film 50 that protrudes outward beyond the electrode body 20 may be folded like a Goebel-top container or a brick-type container.

[0088] 2-7. Seventh Modification In the above embodiment, it is possible to arbitrarily change the outer shape of the exterior body 40. The outer shape of the exterior body 40 may be a cylinder, a prism, or a cube.

[0089] <2-8. Eighth Modification> In the above embodiment, the electrode body 20 is wrapped in one exterior film 50, but it may be wrapped in two or more exterior films 50.

[0090] 10: Electricity storage device 20: Electrode body 40: Exterior body 50: Exterior film 53: Barrier layer 60: Lid body 70, 470: Cover body 80: Lid body 92: Second sealing portion (sealing portion)

Claims

1. An electricity storage device comprising: an electrode body; and an exterior body that seals the electrode body, wherein the exterior body has an exterior film that wraps the electrode body; and a lid that, together with the exterior film, seals the electrode body, wherein the exterior film includes a barrier layer comprising a metallic material, and the lid body includes a portion comprising a metallic material, and the barrier layer of the exterior film and the portion of the lid body comprising a metallic material are directly bonded to each other.

2. The electricity storage device according to claim 1, wherein the portion of the exterior film that is joined to the portion of the lid that contains a metal material is a single layer of the barrier layer.

3. The energy storage device according to claim 1, wherein the exterior film includes another layer laminated on the barrier layer, and a portion of the exterior film that is joined to a portion of the lid body that includes a metal material is a portion of the barrier layer that is partially exposed from the other layer.

4. The electric storage device according to any one of claims 1 to 3, wherein the lid body has a covering body and a lid body joined to the covering body, at least one of the covering body and the lid body is comprised of a metallic material, the exterior body has a sealing portion in which the exterior film is sandwiched between the covering body and the lid body, and the barrier layer of the exterior film is directly joined to the portions of the covering body and the lid body comprised of a metallic material at the sealing portion.

5. An exterior film used as an exterior body for an electricity storage device, the exterior body having a lid body comprising a metallic material, the exterior film including a barrier layer comprising a metallic material, and a portion of the lid body that is joined to a portion comprising the metallic material is a single layer of the barrier layer, or the barrier layer is partially exposed from another layer.

6. A method for manufacturing an electricity storage device, the electricity storage device comprising: an electrode body; and an exterior body that seals the electrode body, the exterior body having an exterior film that wraps the electrode body; and a lid that, together with the exterior film, seals the electrode body, the exterior film includes a barrier layer comprising a metallic material, and the lid body includes a portion comprising a metallic material, the method for manufacturing an electricity storage device comprising: a step of directly joining the barrier layer of the exterior film and the portion of the lid body comprising a metallic material.

Images