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

Abstract

This power storage device comprises an electrode structure and an exterior structure that seals the electrode structure. The exterior structure includes: an exterior film that surrounds the electrode structure; and a lid that comprises a conductive material and that, together with the exterior film, seals the electrode structure. The exterior film has a conductive barrier layer. The conductive barrier layer and a portion of the lid composed of the conductive material are joined together.

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device, an exterior film, an exterior kit, and a lid unit. [Background technology]

[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 wraps the electrode assembly and a lid that is joined to the exterior film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-123686 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned electricity storage device, the lid and the heat-fusible resin layer of the exterior film are joined by, for example, heat sealing, which results in low bonding strength between the lid and the exterior film, and poor sealing of the electrode assembly by the exterior film.

[0005] The present invention aims to provide an electricity storage device with high sealing properties, an exterior film used as an exterior body for the electricity storage device, an exterior body kit including the exterior film, and a method for manufacturing the electricity storage device. [Means for solving the problem]

[0006] An 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 contains a conductive material and seals the electrode body together with the exterior film, the exterior film having a conductive barrier layer, and the conductive barrier layer and a portion of the lid that contains the conductive material are joined together.

[0007] The energy storage device according to a second aspect of the present invention is the energy storage device according to the first aspect, wherein the outer casing has a welding mark which is a trace where the conductive barrier layer and the lid body are joined together, or a trace where the conductive barrier layers of opposing surfaces of the outer casing film are joined together.

[0008] An electricity storage device according to a third aspect of the present invention is the electricity storage device according to the first or second aspect, wherein the exterior body has a covering insulator that covers at least a part of the exterior film.

[0009] An electricity storage device according to a fourth aspect of the present invention is the electricity storage device according to any one of the first to third aspects, wherein the exterior film is constituted only by the conductive barrier layer.

[0010] An electricity storage device according to a fifth aspect of the present invention is the electricity storage device according to any one of the first to fourth aspects, further comprising an insulating member disposed between the conductive barrier layer and the electrode body.

[0011] An energy storage device according to a sixth aspect of the present invention is an energy storage device according to any one of the first to fifth aspects, wherein the lid body includes a lid main body containing the conductive material and joined to the conductive barrier layer, a current extraction portion containing the conductive material, and an insulating portion that insulates the lid main body from the current extraction portion.

[0012] An energy storage device according to a seventh aspect of the present invention is an energy storage device according to any one of the first to sixth aspects, wherein the exterior film has a heat-sealable resin layer partially laminated on the conductive barrier layer, and the exterior body has a first sealing portion where the heat-sealable resin layers of the exterior films are joined together.

[0013] An electricity storage device according to an eighth aspect of the present invention is the electricity storage device according to any one of the first to seventh aspects, further comprising a gas vent valve attached to the lid.

[0014] A ninth aspect of the present invention provides an exterior film used in an exterior of an electricity storage device including an electrode assembly, the exterior assembly including a conductive material and a lid that seals the electrode assembly together with the exterior film, and the exterior film including a conductive barrier layer that is bonded to a portion of the lid that includes the conductive material.

[0015] An exterior packaging film according to a tenth aspect of the present invention is the exterior packaging film according to the ninth aspect, wherein the exterior packaging film has a heat-fusible resin layer partially laminated on the conductive barrier layer.

[0016] An exterior film according to an eleventh aspect of the present invention is an exterior film used in the exterior of an electricity storage device including an electrode assembly, wherein the exterior assembly is made up of a conductive material and has a lid that seals the electrode assembly together with the exterior film, the exterior film has a conductive barrier layer that is joined to a portion of the lid that is made up of the conductive material, and the conductive barrier layer has an exposed portion.

[0017] An exterior package kit according to a twelfth aspect of the present invention includes the exterior package film according to any one of the ninth to eleventh aspects and the lid.

[0018] A thirteenth aspect of the present invention relates to a method for manufacturing an electricity storage device, the method comprising: an electrode assembly; and an exterior body sealing the electrode assembly, the exterior body having an exterior film wrapping the electrode assembly; and a lid containing a conductive material and sealing the electrode assembly together with the exterior film, the exterior film having a conductive barrier layer. The method for manufacturing the electricity storage device includes a step of joining the conductive barrier layer to a portion of the lid containing the conductive material.

[0019] A manufacturing method for an electricity storage device according to a fourteenth aspect of the present invention is the manufacturing method for an electricity storage device according to the thirteenth aspect, wherein the exterior film has a base material layer laminated outside the conductive barrier layer, and the step of joining the conductive barrier layer to the part of the lid body comprising the conductive material is carried out in a state where the base material layer is laminated on the conductive barrier layer.

[0020] A fifteenth aspect of the present invention relates to a method for manufacturing an electric storage device, which is the same as the thirteenth aspect, wherein the exterior body has a coated insulator that coats at least a portion of the exterior film, and the method for manufacturing the electric storage device includes a step of coating at least a portion of the exterior film with the coated insulator, which is performed after the step of joining the conductive barrier layer and the portion of the lid body that contains the conductive material. [Effects of the Invention]

[0021] The electricity storage device, exterior film, exterior kit, and method for manufacturing an electricity storage device according to the present invention can contribute to improving the sealing performance of the electricity storage device. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a perspective view of an electricity storage device according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the exterior film of the power storage device of FIG. 1 in an unfolded state. [Figure 3] 3 is a cross-sectional view taken along line D3-D3 in FIG. 2. [Figure 4] 4 is a cross-sectional view taken along line D4-D4 in FIG. 2. [Figure 5] FIG. 2 is a perspective view of a lid provided in the electricity storage device of FIG. 1. [Figure 6] FIG. 6 is a cross-sectional view taken along line D6-D6 in FIG. [Figure 7] 3 is a flowchart showing an example of a method for manufacturing the electricity storage device of FIG. [Figure 8] 8 is a diagram showing a third step in the method for manufacturing the electricity storage device of FIG. 7. [Figure 9] 8 is a diagram showing a fourth step in the method for manufacturing the electricity storage device of FIG. 7. [Figure 10] 8 is a diagram showing a fifth step in the method for manufacturing the electricity storage device of FIG. 7. [Figure 11] 8 is a diagram showing a sixth step in the method for manufacturing the electricity storage device of FIG. 7. [Figure 12] 8 is a diagram illustrating an eighth step in the method for manufacturing the electricity storage device of FIG. 7. [Figure 13] FIG. 10 is a cross-sectional view of an electricity accumulation device according to a first modified example. [Figure 14] 14 is a cross-sectional view showing an example of a layer structure of an exterior film and a covering insulator included in the electricity storage device of FIG. 13. FIG. [Figure 15] 10 is a flowchart showing an example of a method for manufacturing an electricity accumulation device according to a first modified example. DETAILED DESCRIPTION OF THE INVENTION

[0023] 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.

[0024] [Embodiment] <1-1. Configuration of the power storage device> FIG. 1 is a perspective view schematically showing an electricity storage device 10 of an embodiment. FIG. 2 is a view showing an exterior film 50 provided in the electricity storage device 10 of FIG. 1 in an unfolded state. FIG. 3 is a cross-sectional view taken along line D3-D3 in FIG. 2. FIG. 4 is a cross-sectional view taken along line D4-D4 in FIG. 2. FIG. 5 is a perspective view of a lid body 60 provided in the electricity storage device 10 of FIG. 1. FIG. 6 is a cross-sectional view taken along line D6-D6 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 UD, LR, and FB are common to the subsequent figures.

[0025] The electricity storage device 10 includes an electrode assembly 20 including a current collector 30 (see FIG. 6 ) and an exterior housing 40. The electrode assembly 20 includes electrodes (positive and negative electrodes) constituting an electricity 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, sodium ion 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.

[0026] The exterior body 40 seals the electrode assembly 20. The exterior body 40 includes an exterior film 50 and a lid 60. The exterior film 50 wraps the electrode assembly 20. In this embodiment, the exterior film 50 is wrapped around the electrode assembly 20. The lid 60 is disposed on the side of the electrode assembly 20 in the FB direction. In another example, the electrode assembly 20 may be housed inside an exterior film 50 configured in a cylindrical shape so that openings 40A are formed at both ends in the FB direction, and the openings 40A may be closed by the lid 60. In yet another example, the electrode assembly 20 connected to the lid 60 may be housed inside an exterior film 50 configured in a cylindrical shape so that the openings 40A are formed, and the openings 40A may be closed by the lid 60. The exterior body 40 has a pair of first surfaces 41A, 41B and a pair of second surfaces 42A, 42B. In this embodiment, the pair of first surfaces 41A, 41B are substantially the same size. In this 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 exterior film 50 and the lid 60 constitute an exterior kit 60X.

[0027] 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.

[0028] 3, the exterior film 50 is, for example, a laminated body (laminate film) having, in this order, a base material layer 51 and a conductive barrier layer 52. In this laminated body, the base material layer 51 is a layer that is provided as needed.

[0029] 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.

[0030] 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 conductive 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. From the viewpoint of film strength, the thickness of the substrate layer 51 is preferably, for example, 5 to 300 μm, and more preferably 5 to 150 μm. The substrate layer 51 may be a coating layer. The material constituting the coating layer is, for example, an epoxy resin, a polyurethane resin, a polyimide resin, or a fluororesin.

[0031] The conductive barrier layer 52 is a layer that at least prevents the penetration of moisture. The conductive barrier layer 52 is bonded to the base layer 51, for example, via an adhesive layer 53. In this embodiment, the conductive barrier layer 52 is bonded to a lid main body 70 of the lid body 60, which will be described later, by, for example, welding.

[0032] The conductive barrier layer 52 is composed of a metal material. Specific examples of the metal material that can be used to form the conductive barrier layer 52 include aluminum, aluminum alloys, titanium, titanium alloys, steel (including stainless steel), copper, copper alloys, nickel, nickel alloys, magnesium, magnesium alloys, niobium, iron, antimony-doped tin oxide, and tin-doped indium oxide. When a metal foil is used as the material that forms the conductive barrier layer 52, the metal foil preferably includes at least one of an aluminum alloy foil and a stainless steel foil.

[0033] The metallic material constituting the conductive barrier layer 52 may contain recycled metallic materials. Examples of recycled metallic materials include recycled aluminum alloys, stainless steels, titanium steels, and steel plates. These recycled materials can be obtained by known methods. Recycled aluminum alloys can be obtained, for example, by the manufacturing method described in International Publication No. 2022 / 092231. The conductive barrier layer 52 may be composed solely of recycled materials, or may be composed of a mixture of recycled and virgin materials. Note that recycled metallic materials refer to metallic materials that have been made reusable by collecting, isolating, and refining various products used in the market or waste materials from manufacturing processes. Furthermore, virgin metallic materials refer to new metallic materials refined from natural metallic resources (raw materials) and are not recycled materials.

[0034] 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, and 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. 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 defined 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 packaging 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 specified in JIS H4000:2017 A5005P-O, JIS H4000:2017 A5050P-O, and JISH4000:2017 A5052P-O.

[0035] Examples of 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.

[0036] Specific examples of austenitic stainless steels that can be used to form the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

[0037] In the case of a metal foil, the thickness of the conductive barrier layer 52 should be sufficient to function as a barrier layer that prevents moisture penetration, and may be, for example, about 5 to 1000 μm. The thickness of the conductive 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 conductive 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 conductive 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 conductive 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 conductive 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 still 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 still 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 conductive 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.

[0038] Furthermore, when the conductive barrier layer 52 is an aluminum foil, it is preferable that a corrosion-resistant coating be provided on at least the surface opposite the base layer 51 to prevent dissolution and corrosion. The conductive 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 provides corrosion resistance (e.g., acid resistance, alkali resistance, etc.) to the conductive barrier layer 52 by performing, for example, a hydrothermal conversion treatment such as boehmite treatment, a chemical conversion treatment, an anodizing treatment, a plating treatment using nickel or chromium, or a corrosion prevention treatment such as applying a coating agent on the surface of the conductive barrier layer 52. Specifically, the corrosion-resistant coating refers to a coating that improves the acid resistance of the conductive barrier layer 52 (acid-resistant coating), a coating that improves the alkali resistance of the conductive 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 conductive barrier layer 52 may have not only one layer but also multiple layers. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the metal foil surface is dissolved using 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 conductive barrier layer 52 is provided with a corrosion-resistant coating, the corrosion-resistant coating is also included in the conductive barrier layer 52.

[0039] The corrosion-resistant coating prevents delamination between the conductive barrier layer 52 (e.g., aluminum alloy foil) and the base layer 51 when the exterior film 50 is formed, prevents dissolution and corrosion of the surface of the conductive barrier layer 52 due to hydrogen fluoride produced by a reaction between an electrolyte and water, and particularly prevents dissolution and corrosion of aluminum oxide present on the surface of the conductive barrier layer 52 when the conductive barrier layer 52 is an aluminum alloy foil, and improves the adhesion (wettability) of the surface of the conductive barrier layer 52, thereby preventing delamination between the base layer 51 and the conductive barrier layer 52 during heat sealing and between the base layer 51 and the conductive barrier layer 52 during forming.

[0040] In the conductive barrier layer 52, in a portion other than the portion bonded to the lid body 60, an arbitrary layer such as a heat-sealable resin layer 54 (see FIG. 4) may be laminated on the surface opposite to the base material layer 51. In this embodiment, the heat-sealable resin layer 54 is laminated on the conductive barrier layer 52 in a predetermined range including the first edge 50A of the exterior film 50 and in a predetermined range including the second edge 50B. In this embodiment, the conductive barrier layer 52 is exposed in the portion of the exterior film 50 other than the portion where the heat-sealable resin layer 54 is laminated. The portion indicated by dots in FIG. 2 is an example of the range where the heat-sealable resin layer 54 is laminated.

[0041] The heat-sealable resin layer 54 is bonded to the conductive barrier layer 52 via, for example, an adhesive layer 55. The heat-sealable resin layer 54 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 54 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 viewpoints of sealability and strength, the thickness of the heat-sealable resin layer 54 is preferably, for example, 20 to 300 μm, and more preferably 40 to 150 μm.

[0042] The exterior film 50 preferably has one or more layers with a buffer function (hereinafter referred to as "buffer layer") outside the heat-sealable resin layer 54, more preferably outside the conductive 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 conductive barrier layer 52, or the like interposed therebetween.

[0043] 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, and most preferably in the range of 1000 μm to 3000 μm.

[0044] When the buffer layer is made of rubber, the lower limit of the buffer layer thickness is preferably 0.5 mm, more preferably 1.0 mm. When the buffer layer is made of rubber, the upper limit of the buffer layer thickness is preferably 10 mm, more preferably 5.0 mm, and even more preferably 2.0 mm. When the buffer layer is made of rubber, the preferred ranges of the buffer layer thickness are 1.0 mm to 2.0 mm, 1.0 mm to 5.0 mm, 1.0 mm to 10 mm, 0.5 mm to 2.0 mm, 0.5 mm to 5.0 mm, and 0.5 mm to 10 mm.

[0045] 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 the manufacture of the energy storage device 10.

[0046] The lid body 60 seals the electrode body 20 together with the exterior film 50. The lid body 60 has a lid main body 70, a current extraction portion 80, and an insulating portion 90.

[0047] The lid main body 70 and the current extracting portion 80 are composed of a conductive material. "Composed of a conductive material" means that, when the entire material constituting the lid main body 70 or the current extracting portion 80 is taken as 100% by mass, the content of the conductive 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 lid main body 70 and the current extracting portion 80 can contain materials other than the conductive material in addition to the conductive material. At least one of the lid main body 70 and the current extracting portion 80, which are composed of a conductive material, preferably has the corrosion-resistant coating described for the conductive barrier layer 52.

[0048] The conductive material forming the lid body 70 and the current extracting portion 80 is, for example, a metal material. The metal material forming the lid body 70 and the current extracting portion 80 is, for example, aluminum, an aluminum alloy, nickel, copper, or a copper alloy. From the viewpoint of increasing the bonding strength between the lid body 70 and the conductive barrier layer 52 of the exterior film 50, it is preferable that the conductive material forming the lid body 70 and the metal material forming the conductive barrier layer 52 of the exterior film 50 are the same material.

[0049] The conductive material constituting the current extraction portion 80 may be the same as or different from the conductive material constituting the lid body 70. For example, when the electrode body 20 is a lithium-ion battery, the current extraction portion 80 connected to the positive electrode is preferably made of aluminum or an aluminum alloy. The current extraction portion 80 connected to the negative electrode is preferably made of nickel, copper, or a copper alloy. The material constituting the current extraction portion 80 connected to the negative electrode may be nickel-plated copper. The material constituting the current extraction portion 80 may include recycled metal materials.

[0050] The lid body 70 is, for example, plate-shaped and has a first surface 71, a second surface 72, a film bonding portion 73, and a through-hole 70X. The first surface 71 faces the electrode body 20. The end portion 31 (see FIG. 6) of the current collector 30 is bonded to the first surface 71, for example. The second surface 72 is the surface opposite to the first surface 71.

[0051] The film bonding portion 73 is connected to the first surface 71 and the second surface 72 and is bonded to the conductive barrier layer 52 of the exterior film 50. The film bonding portion 73 includes a first bonding surface 73A, a second bonding surface 73B, a third bonding surface 73C, and a fourth bonding surface 73D. The first bonding surface 73A forms the top surface of the lid 60. The first bonding surface 73A extends in a first direction (in this embodiment, the LR direction) when viewed from the front of the lid 60. The second bonding surface 73B and the third bonding surface 73C are connected to the first bonding surface 73A and form side surfaces of the lid 60. The second bonding surface 73B and the third bonding surface 73C extend in a second direction (in this embodiment, the UD direction) that intersects with the first direction when viewed from the front of the lid 60. In this embodiment, the first direction and the second direction are perpendicular to each other when viewed from the front of the lid 60. The first direction and the second direction do not have to be perpendicular to each other in a front view of the lid 60. The fourth bonding surface 73D forms the lower surface of the lid 60. The fourth bonding surface 73D extends in the first direction (the LR direction in this embodiment) in a front view of the lid 60.

[0052] When the lid body 60 is plate-shaped, the film bonding portion 73 of the lid body 60 preferably has a certain thickness in the FB direction so that deformation of the exterior body 40 is suppressed even when the power storage device 10 is placed on top of it. From another perspective, when the lid body 60 is plate-shaped, the film bonding portion 73 preferably has a certain thickness in the FB direction so that the film bonding portion 73 can be suitably bonded to the conductive barrier layer 52 of the exterior film 50 when forming the second sealing portion 120 described below. The minimum thickness of the film bonding portion 73 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 film bonding portion 73 in the FB direction is, for example, 20 mm, more preferably 15 mm, and even more preferably 10 mm. The maximum thickness of the film bonding portion 73 in the FB direction may be 20 mm or more. Preferred ranges for the thickness of the film joint portion 73 in the FB direction 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 film joint portion 73 may vary depending on the region of the lid main body 70. When the thickness of the film joint portion 73 varies depending on the region, the thickness of the film joint portion 73 is the thickness of the thickest portion.

[0053] The film bonding portion 73 further includes boundaries 74, 75, 76, and 77. The boundary 74 is the boundary between the first bonding surface 73A and the second bonding surface 73B. The boundary 75 is the boundary between the first bonding surface 73A and the third bonding surface 73C. The boundary 76 is the boundary between the fourth bonding surface 73D and the second bonding surface 73B. The boundary 77 is the boundary between the fourth bonding surface 73D and the third bonding surface 73C. The boundaries 74 to 77 may have corners or may be rounded by being subjected to a rounding process. In this embodiment, the boundaries 74 to 77 are corners.

[0054] The through-hole 70X is formed approximately in the center of the lid main body 70. The through-hole 70X penetrates the first surface 71 and the second surface 72 of the lid main body 70. The shape of the through-hole 70X when viewed from the front or rear of the lid body 60 can be selected arbitrarily. In the example shown in FIG. 5, the shape of the through-hole 70X when viewed from the front or rear of the lid body 60 is rectangular. The shape of the through-hole 70X when viewed from the front or rear of the lid body 60 may also be a square, circle, ellipse, triangle, or polygon with pentagons or more sides.

[0055] The current extraction section 80 is an element that outputs current, and is connected to, for example, an external device. The shape of the current extraction section 80 can be selected arbitrarily. In this embodiment, the current extraction section 80 has a rectangular parallelepiped block shape. At least a portion of the current extraction section 80 is housed in the through-hole 70X. In this embodiment, the entire current extraction section 80 is housed in the through-hole 70X. The current extraction section 80 may protrude to the outside of the lid main body 70 from at least one of the first surface 71 and the second surface 72 of the lid main body 70.

[0056] The insulating portion 90 insulates the lid main body 70 from the current extraction portion 80. Therefore, even when the conductive barrier layer 52 and the lid main bodies 70 of a pair of lid bodies 60 are joined together, the current extraction portion 80 of one lid body 60 and the current extraction portion 80 of the other lid body 60 are not electrically connected to each other. The material constituting the insulating portion 90 can be selected arbitrarily as long as it can insulate the lid main body 70 from the current extraction portion 80. Examples of materials constituting the insulating portion 90 include rubber, resin material, ceramic, and glass. The insulating portion 90 is arranged to fill the gap between the current extraction portion 80 and the inner surface of the through-hole 70X.

[0057] From the viewpoint of suppressing short circuits between the conductive barrier layer 52 of the exterior film 50 and the electrode assembly 20, it is preferable that an insulating member 100 be disposed inside the exterior assembly 40, at least partially between the conductive barrier layer 52 and the electrode assembly 20. In this embodiment, the insulating member 100 is disposed so as to face substantially the entire conductive barrier layer 52. The insulating member 100 is, for example, a film or an insulating coating. The insulating member 100 may or may not be bonded to the conductive barrier layer 52.

[0058] In this embodiment, the first sealed portion 110 is formed by heat-sealing the opposing surfaces (thermal adhesive resin layers 54) of the exterior film 50 wrapped around the electrode body 20. Note that if the exterior film 50 does not have the thermal adhesive resin layer 54, the first sealed portion 110 may be formed by joining the conductive barrier layers 52 on the opposing surfaces of the exterior film 50 together, for example, by welding.

[0059] The first sealed portion 110 is formed by heat-sealing a portion of the exterior film 50 shown in FIG. 2 including the first edge 50A and a portion of the exterior film 50 including the second edge 50B. The first sealed portion 110 extends in the longitudinal direction (FB direction) of the exterior body 40. The position at which the first sealed portion 110 is formed in the exterior body 40 can be selected arbitrarily. In the present embodiment, the base 110X of the first sealed portion 110 is preferably located on the side 43 at the boundary between the first surface 41A and the second surface 42A of the exterior body 40. The base 110X of the first sealed portion 110 may be located on any surface of the exterior body 40. In the present embodiment, the first sealed portion 110 protrudes outward beyond the electrode assembly 20 in a plan view. The first sealed portion 110 may be folded, for example, toward the second surface 42A of the exterior body 40 or toward the first surface 41A.

[0060] In this embodiment, the second sealing portion 120 is formed by joining the conductive barrier layer 52 of the exterior film 50 and the film joint portion 73 of the lid 60. When the conductive barrier layer 52 of the exterior film 50 and the film joint portion 73 are joined by, for example, welding, typically, at least a portion of the base material layer 51 and the adhesive layer 53 of the exterior film 50 located above the film joint portion 73 melts. As a result, weld marks 40X are observed on the exterior film 50 located above the film joint portion 73. When the first sealing portion 110 is formed by joining the conductive barrier layers 52 on opposing surfaces of the exterior film 50 by welding, the weld marks 40X may also be observed on the first sealing portion 110. Note that FIG. 6 shows an example in which the base material layer 51 and the adhesive layer 53 of the exterior film 50 located above the film joint portion 73 are entirely melted; however, the base material layer 51 and the adhesive layer 53 of the exterior film 50 located above the film joint portion 73 may also partially melt. Depending on the welding method, at least a portion of the base material layer 51 and adhesive layer 53 of the exterior film 50 located on the film joint portion 73 may remain. When the conductive barrier layer 52 of the exterior film 50 and the film joint portion 73 are joined by welding, the time required for joining can be shorter than when the exterior film 50 and the lid main body 70 are joined by heat sealing, for example, via an adhesive film.

[0061] <1-2. Method for manufacturing electricity storage devices> FIG. 7 is a flowchart showing an example of a method for manufacturing the electricity storage device 10. The method for manufacturing the electricity storage device 10 includes, for example, a first step, a second step, a third step, a fourth step, a fifth step, a sixth step, a seventh step, and an eighth step. The first step to the eighth step are performed, for example, by a manufacturing apparatus for the electricity storage device 10. At least some of the first step to the eighth step may be performed by an operator. Note that the first step to the eighth step are names of the steps in the method for manufacturing the electricity storage device 10 specified for convenience, and do not necessarily refer to the order of the steps. The order of the following steps can be changed as desired as long as there is no technical contradiction.

[0062] In the first process of step S1, the manufacturing device places a pair of lid bodies 60 on the sides of the electrode body 20 in the FB direction, and electrically connects the current collector 30 and the current extraction part 80.

[0063] The second step of step S2 is performed after the first step. In the second step, the manufacturing apparatus wraps the electrode assembly 20 and the lid body 60 in the exterior film 50. Note that in the second step, in order to form a gas pocket 300 described below, an exterior film 50 having a larger area than the exterior film 50 of the finished electricity storage device 10 is used. In the second step, the manufacturing apparatus wraps the exterior film 50 around the electrode assembly 20 and the lid body 60 while applying tension to the exterior film 50, while restricting the movement of the electrode assembly 20 and the lid body 60 with a restricting means. The restricting means is, for example, a groove into which the electrode assembly 20 and the lid body 60 are fitted. The restricting means may be a device that applies an external force to the electrode assembly 20 and the lid body 60 to prevent the electrode assembly 20 and the lid body 60 from moving. The restricting means may be a device that applies a force to the electrode assembly 20 and the lid body 60 in a direction opposite to the direction in which the exterior film 50 is pulled. The restricting means may include a roller that runs on the exterior film 50 while the exterior film 50 is being pulled in order to remove wrinkles in the exterior film 50. The electrode body 20 may be housed inside an exterior film 50 that is configured in a cylindrical shape so that openings 40A are formed at both ends in the FB direction, and after the current collector 30 and the current extracting portion 80 are joined, the openings 40A may be closed with the lid 60. In yet another example, the electrode body 20 connected to the current extracting portion 80 of the lid 60 may be housed inside an exterior film 50 that is configured in a cylindrical shape so that openings 40A are formed at both ends in the FB direction, and the openings 40A may be closed with the lid 60.

[0064] The third process of step S3 is performed after the second process. As shown in Fig. 8, in the third process, the manufacturing equipment forms a first FB-direction joint 111 having an unjoined portion 110Z in the center. The hatched area in Fig. 8 indicates an example of the region where the first FB-direction joint 111 is formed.

[0065] The fourth step of step S4 is performed after the third step. As shown in Fig. 9, in the fourth step, the manufacturing equipment forms a second short side bonding portion 121. The second short side bonding portion 121 is a portion where the second bonding surface 73B and the third bonding surface 73C of the lid main body 70 are bonded to the conductive barrier layer 52 of the exterior film 50. The hatched portion in Fig. 9 indicates an example of the region where the second short side bonding portion 121 is formed.

[0066] The fifth step of step S5 is performed after the fourth step. As shown in Fig. 10, in the fifth step, the manufacturing equipment forms a second long side bonding portion 122. The second long side bonding portion 122 is a portion where the first bonding surface 73A and the fourth bonding surface 73D of the lid main body 70 are bonded to the conductive barrier layer 52 of the exterior film 50. The hatched portion in Fig. 10 indicates an example of the region where the second long side bonding portion 122 is formed. The fourth and fifth steps may be performed simultaneously.

[0067] The sixth step of step S6 is performed after the fifth step. As shown in FIG. 11 , in the sixth step, the manufacturing apparatus forms the first LR joint 112. In the sixth step, the first LR joint 112 is formed so as to partially overlap the first FB joint 111 in a portion including the side 43. The hatched portion in FIG. 11 indicates an example of the region where the first LR joint 112 is formed. Completion of the sixth step results in the completion of a gas pocket 300 having a larger area in a planar view than the first sealing portion 110 of the completed power storage device 10.

[0068] The seventh step of step S7 is performed after the sixth step. In the seventh step, the manufacturing equipment injects an electrolyte solution through the opening of the gas pocket 300. As shown in FIG. 12, after the electrolyte solution is injected, the edges of the gas pocket 300, including the opening, are joined to form a pocket sealing portion 310. An aging step is performed after the seventh step. Gas generated by the aging step is stored in the gas pocket 300. The gas stored in the gas pocket 300 is discharged through an opening formed by cutting a portion of the gas pocket 300. The gas pocket 300 is cut, for example, along the dashed dotted line XA shown in FIG. 12 to form an opening for discharging the gas.

[0069] The eighth step of step S8 is performed after the seventh step and after the aging step is completed. In the eighth step, the manufacturing equipment forms the first sealing portion 110. In the eighth step, the first FB direction bonding portion 111 may or may not be bonded again.

[0070] <1-3. Actions and Effects of Electricity Storage Devices> The power storage device 10 has high bonding strength because the conductive barrier layer 52 of the exterior film 50 is bonded to the lid main body 70, which is a portion of the lid body 60 that contains a conductive material. Therefore, the power storage device 10 has high sealing performance.

[0071] [2. Modifications] The above-described embodiments are examples of possible forms of the electricity storage device, exterior film, exterior kit, and electricity storage device manufacturing method of the present invention, and are not intended to limit the forms. The electricity storage device, exterior film, exterior kit, and electricity storage device of 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, modified, or omitted, or forms in which a new configuration is added to the embodiments. Some examples of modified embodiments are shown below. Note that the following modified forms can be combined with each other as long as there is no technical contradiction.

[0072] <2-1. First modified example> 13 is a cross-sectional view of the electricity storage device 10 of the first modified example. In the above embodiment, the exterior film 50 may be composed of only the conductive barrier layer 52. In the first modified example, the exterior film 50 is preferably covered with a covering insulator 150. In the first modified example, the exterior film 50 and the covering insulator 150 are separate members. The covering insulator 150 is preferably joined to the conductive barrier layer 52 of the exterior film 50.

[0073] The specific configuration of the insulating coating 150 can be selected arbitrarily as long as it can insulate the conductive barrier layer 52 from the outside of the exterior casing 40. For example, as shown in FIG. 14 , the insulating coating 150 may be a laminate film in which a first layer 151, a second layer 152, and a third layer 153 are stacked in this order from the outside. The first layer 151 and the third layer 153 may be made of, for example, polypropylene. The second layer 152 may be made of, for example, polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate. It is preferable that the second layer 152 be subjected to a surface treatment such as ozone treatment or anchor coating treatment. The insulating coating 150 may also be an insulating tape.

[0074] In the electricity storage device 10 of the first modification, the conductive barrier layer 52 of the exterior film 50 and the film joint portion 73 of the lid main body 70 are joined together, and then the exterior film 50 is covered with the covering insulator 150. When the conductive barrier layer 52 of the exterior film 50 and the film joint portion 73 of the lid main body 70 are joined together by, for example, welding, a welding mark 40Y is visible in the conductive barrier layer 52 of the exterior film 50 located above the film joint portion 73. It is preferable that the covering insulator 150 covers the exterior film 50 so as to cover at least the welding mark 40Y. When the covering insulator 150 covers the exterior film 50 so as to cover at least the welding mark 40Y, the welding mark 40Y can be confirmed by, for example, peeling the covering insulator 150 from the exterior film 50.

[0075] If an abnormality occurs in the electrode assembly 20, gas may be generated inside the exterior body 40. If the electricity storage device 10 is a lithium-ion battery, gases such as volatile organic solvents, carbon monoxide, carbon dioxide, methane, ethane, hydrogen, and hydrogen fluoride may be generated inside the exterior body 40 due to the evaporation and decomposition of the organic solvent in the electrolyte. If the electricity storage device 10 is a capacitor, gas may be generated inside the exterior body 40 due to a chemical reaction in the capacitor. If the electricity storage device 10 is an all-solid-state battery, the electrode assembly 20 may contain a solid electrolyte that can generate gas. For example, if the solid electrolyte is a sulfide-based electrolyte, hydrogen sulfide gas may be generated. If gas is generated inside the exterior body 40, the internal pressure of the exterior body 40 increases. For this reason, it is preferable to be able to discharge the gas generated inside the exterior body 40 to the outside of the exterior body 40. Furthermore, since gas is generated from the electrode assembly 20 during the aging process, it is preferable to discharge the generated gas to the outside of the exterior body 40.

[0076] From this perspective, the electricity storage device 10 of the first modified example may include a gas vent valve 200 so that gas generated inside the exterior body 40 can be discharged to the outside of the exterior body 40. The gas vent valve 200 may be a known valve-type check valve that is capable of repeatedly releasing gas, such as a ball spring type, poppet type, duckbill type, umbrella type, or diaphragm type. The gas vent valve 200 may also be a break valve.

[0077] The gas vent valve 200 includes a housing 210, a valve mechanism 220, and an attachment portion 230. The housing 210 is made of, for example, metal or resin. The housing 210 has, for example, a cylindrical shape and houses the valve mechanism 220 therein. An outlet 210A for discharging gas is formed on the end face of the housing 210 opposite the attachment portion 230.

[0078] The valve mechanism 220 has a spring, a valve body, and a valve seat. That is, in this embodiment, the gas vent valve 200 is a ball-spring type check valve.

[0079] The mounting portion 230 is connected to the housing 210. The mounting portion 230 is made of metal or resin. The mounting portion 230 may be formed integrally with the housing 210, or may be formed separately from the housing 210 and joined to the housing 210.

[0080] An inlet 230A facing the inside of the exterior body 40 is formed on the end face of the attachment part 230 opposite to the housing 210. When gas is generated inside the exterior body 40 and the internal pressure of the exterior body 40 becomes equal to or greater than the valve opening pressure of the valve mechanism 220, the valve mechanism 220 opens. When the valve mechanism 220 opens, the gas passes through the inlet 230A, the inside of the attachment part 230, the inside of the housing 210, and the outlet 210A in that order, and is discharged to the outside.

[0081] The gas vent valve 200 is attached to the lid body 70. The attachment portion 230 of the gas vent valve 200 is inserted into a hole 70Y formed in the lid body 70, for example.

[0082] In the example shown in FIG. 13 , at least a portion of the mounting portion 230 of the gas vent valve 200 is embedded inside the lid body 70. Note that at least a portion of the housing 210 may be embedded inside the lid body 70. The position of the inlet 230A of the mounting portion 230 can be selected arbitrarily. The inlet 230A may be located on the first surface 71 of the lid body 70, may be located closer to the electrode assembly 20 than the first surface 71 of the lid body 70, or may be located inside the lid body 70. From the viewpoint of suppressing interference between the gas vent valve 200 and the electrode assembly 20, it is preferable that the inlet 230A be located as far away from the electrode assembly 20 as possible. In the example shown in FIG. 13 , the inlet 230A is located on the first surface 71 of the lid body 70.

[0083] In the electricity storage device 10 of the first modification, a hole 70Z for injecting an electrolyte solution is preferably formed in the lid body 60. In the example shown in Fig. 13, the hole 70Z is formed in the lid main body 70. In the completed electricity storage device 10, the hole 70Z is preferably closed with, for example, a resin material or the like.

[0084] 15 is a flowchart showing an example of a method for manufacturing the electricity storage device 10 of the first modified example. The method for manufacturing the electricity storage device 10 includes, for example, an eleventh step, a twelfth step, a thirteenth step, a fourteenth step, a fifteenth step, and a sixteenth step. The eleventh step to the sixteenth step are performed, for example, by a manufacturing apparatus for the electricity storage device 10. At least some of the eleventh step to the sixteenth step may be performed by an operator. Note that the eleventh step to the sixteenth step are names of the steps in the method for manufacturing the electricity storage device 10 of the first modified example for convenience, and do not necessarily indicate the order of the steps. The order of the following steps can be changed as desired as long as there is no technical contradiction.

[0085] In the eleventh process of step S11, the manufacturing apparatus places a pair of lid bodies 60 on the sides of the electrode body 20 in the FB direction, and electrically connects the current collector 30 and the current extraction unit 80. Note that a gas vent valve 200 is attached to one of the pair of lid bodies 60. The gas vent valves 200 may be attached to both of the lid bodies 60.

[0086] The twelfth step of step S12 is performed after the eleventh step. In the twelfth step, the manufacturing equipment wraps the electrode body 20 and the lid body 60 in an exterior film 50. As will be described later, in the electricity storage device 10 of the first modified example, the gas generated in the aging step is discharged by the gas vent valve 200, so there is no need to form a gas pocket 300. For this reason, in the twelfth step, an exterior film 50 having substantially the same area as the exterior film 50 of the finished electricity storage device 10 is used.

[0087] In step 12, the manufacturing apparatus winds the exterior film 50 around the electrode assembly 20 and the lid body 60 while tension is applied to the exterior film 50, while restricting the movement of the electrode assembly 20 and the lid body 60 with a restricting means. The restricting means is, for example, a groove into which the electrode assembly 20 and the lid body 60 are fitted. The restricting means may be a device that applies an external force to the electrode assembly 20 and the lid body 60 to prevent the electrode assembly 20 and the lid body 60 from moving. The restricting means may be a device that applies a force to the electrode assembly 20 and the lid body 60 in a direction opposite to the direction in which the exterior film 50 is pulled. The restricting means may include a roller that runs on the exterior film 50 while the exterior film 50 is being pulled, in order to remove wrinkles in the exterior film 50. The electrode body 20 may be housed inside an exterior film 50 configured in a cylindrical shape so that openings 40A are formed at both ends in the FB direction, and after the current collector 30 and the current extraction portion 80 are joined, the openings 40A may be closed with the lid 60. In yet another example, the electrode body 20 connected to the current extraction portion 80 of the lid 60 may be housed inside an exterior film 50 configured in a cylindrical shape so that openings 40A are formed at both ends in the FB direction, and the openings 40A may be closed with the lid 60.

[0088] The thirteenth step of step S13 is performed after the twelfth step. In the thirteenth step, the manufacturing apparatus joins the conductive barrier layer 52 of the exterior film 50 and the film joint portion 73 of the lid main body 70 by, for example, welding. When the thirteenth step is completed, a weld mark 40X is formed in at least a part of the conductive barrier layer 52 located on the film joint portion 73 of the exterior film 50.

[0089] The 14th step of step S14 is performed before or after the 13th step. In the 14th step, the manufacturing apparatus forms the first sealing portion 110 by bonding the opposing conductive barrier layers 52 of the exterior film 50 together.

[0090] The fifteenth step of step S15 is performed after the fourteenth step. In the fifteenth step, the manufacturing apparatus joins the coated insulator 150 and the exterior film 50 together.

[0091] The 16th step of step S16 is performed before or after the 15th step. In the 16th step, the manufacturing apparatus injects an electrolyte solution through the hole 70Z of the lid body 70. After the 16th step, an aging step is performed. Gas generated during the aging step is discharged to the outside via the gas vent valve 200.

[0092] The electricity storage device 10 of the first modified example has the following advantages in addition to the advantages obtained by the electricity storage device 10 of the embodiment. The electricity storage device 10 of the first modified example includes the gas vent valve 200, and therefore gas generated in the aging step is discharged through the gas vent valve 200. Therefore, in the electricity storage device 10 of the first modified example, it is not necessary to form a gas pocket for storing gas generated in the aging step. The electricity storage device 10 of the first modified example can reduce manufacturing costs because less of the exterior film 50 is discarded.

[0093] <2-2. Second modified example> In the above embodiment, the exterior film 50 of the electricity storage device 10 may protrude outward in the FB direction beyond at least 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 film 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. In the second modified example, the length of the current extraction section 80 in the FB direction is preferably long enough to be exposed from the portion of the exterior film 50 that protrudes outward beyond the lid body 60.

[0094] <2-3.Third modified example> 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 second 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 container.

[0095] <2-4. Fourth Modification> In the above embodiment, the outer shape of the exterior body 40 can be changed as desired. The outer shape of the exterior body 40 may be a cylinder, a prism, or a cube.

[0096] <2-5. 10th Variation> 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. [Explanation of symbols]

[0097] 10: Energy storage device 20: Electrode body 40: Exterior body 40X, 40Y: Weld marks 50: Exterior film 51: Base material layer 52: Conductive barrier layer 54: Heat-fusible resin layer 60: Lid 60X: Exterior body kit 70: Lid body 80: Current extraction part 90: Insulation part 100: Insulating material 110: First sealing portion 150: Covered insulation 200: Gas release valve

Claims

1. An electrode body; an exterior body that seals the electrode body, The exterior body is an exterior film that wraps the electrode body; a lid body that contains a conductive material and seals the electrode body together with the exterior film, the exterior film has a conductive barrier layer; the conductive barrier layer and a portion of the lid body that contains the conductive material are directly bonded to each other, The exterior body has a covering insulator that covers at least a portion where the conductive barrier layer of the exterior film and a portion of the lid body that contains the conductive material are joined. Energy storage device.

2. An electrode body; an exterior body that seals the electrode body, The exterior body is an exterior film that wraps the electrode body; a lid body that contains a conductive material and seals the electrode body together with the exterior film, The exterior film is a conductive barrier layer; and a heat-sealable resin layer partially laminated on the conductive barrier layer, the conductive barrier layer and a portion of the lid body that contains the conductive material are directly bonded to each other, the exterior body has a first sealing portion in which the heat-sealable resin layers of the exterior film are joined together, The thermal adhesive resin layer is partially laminated only on a portion of the conductive barrier layer where the first sealing portion is to be formed. Energy storage device.

3. The exterior body has a welding mark, which is a mark where the conductive barrier layer and the lid body are joined together, or a mark where opposing surfaces of the exterior film are joined together. The electricity storage device according to claim 1 or 2.

4. The exterior film is composed only of the conductive barrier layer. The electricity storage device according to claim 1 .

5. an insulating member disposed between the conductive barrier layer and the electrode body; The electricity storage device according to claim 1 or 2.

6. The lid body is a lid body including the conductive material and bonded to the conductive barrier layer; a current extraction portion including a conductive material; an insulating portion that insulates the lid body from the current extracting portion, The electricity storage device according to claim 1 or 2.

7. A gas vent valve attached to the lid The electricity storage device according to claim 1 or 2.

8. A method for manufacturing an electricity storage device, comprising: The electricity storage device is An electrode body; an exterior body that seals the electrode body, The exterior body is an exterior film that wraps the electrode body; a lid body that contains a conductive material and seals the electrode body together with the exterior film, the exterior film has a conductive barrier layer; the conductive barrier layer and a portion of the lid body that contains the conductive material are directly bonded to each other, the exterior body has a covering insulator that covers at least a portion where the conductive barrier layer of the exterior film and a portion of the lid body that contains the conductive material are joined, The method for manufacturing the electricity storage device includes: a step of directly bonding the conductive barrier layer to a portion of the lid body that contains the conductive material. A method for manufacturing an electricity storage device.

9. A method for manufacturing an electricity storage device, comprising: The electricity storage device is An electrode body; an exterior body that seals the electrode body, The exterior body is an exterior film that wraps the electrode body; a lid body that contains a conductive material and seals the electrode body together with the exterior film, The exterior film is a conductive barrier layer; and a heat-sealable resin layer partially laminated on the conductive barrier layer, the conductive barrier layer and a portion of the lid body that contains the conductive material are directly bonded to each other, the exterior body has a first sealing portion in which the heat-sealable resin layers of the exterior film are joined together, the thermal adhesive resin layer is partially laminated only on a portion of the conductive barrier layer where the first sealing portion is to be formed, The method for manufacturing the electricity storage device includes: a step of directly bonding the conductive barrier layer to a portion of the lid body that contains the conductive material. A method for manufacturing an electricity storage device.

10. the exterior film has a base material layer laminated on the outer side of the conductive barrier layer, The step of directly bonding the conductive barrier layer to the portion of the lid body that contains the conductive material is performed in a state where the base material layer is laminated on the conductive barrier layer. The method for manufacturing the electricity storage device according to claim 8 or 9.

11. the exterior body has a covering insulator that covers at least a part of the exterior film, The method for manufacturing the electricity storage device includes: a step performed after a step of directly bonding the conductive barrier layer and a portion of the lid body that contains the conductive material, and covering at least a portion of the exterior film with the covering insulator. The method for manufacturing the electricity storage device according to claim 9 .

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