Power storage device, lid member, and method for manufacturing power storage device

Abstract

A power storage device according to the present invention comprises: an electrode body; an exterior film wrapped around the electrode body; and a lid member that includes an electroconductive material and seals the electrode body together with the exterior film. The lid member comprises a lid body and a protrusion part that is integrally formed with the lid body and protrudes from the lid body in the direction opposite from the electrode body. The protrusion part has a hollow shape.

Description

Electricity storage device, lid, and method for manufacturing an electricity storage device

[0001] The present invention relates to an electricity storage device, a lid, 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 including a current collector, an exterior body that seals the electrode assembly, and an electrode terminal connected to the current collector. The exterior body includes an exterior film that encases the electrode assembly and a lid that is joined to the exterior film. The electrode terminal is inserted into a through-hole formed in the lid. An end of the current collector is joined to the electrode terminal.

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

[0004] In the above-mentioned electricity storage device, in order to simplify the configuration, it is conceivable to form the lid body from metal and to join the lid body and the current collector. In this case, it is preferable that an element that outputs current to an external device is formed on the lid body. If the lid body and the element that outputs current are formed as separate bodies and then joined, there is a risk of a poor connection. If a poor connection occurs between the lid body and the element that outputs current, the current cannot be output appropriately.

[0005] An object of the present invention is to provide an electricity storage device that can suitably output current, a lid body used in this electricity storage device, and a method for manufacturing this electricity storage device.

[0006] The energy storage device according to a first aspect of the present invention comprises an electrode body, an exterior film that wraps the electrode body, and a lid body that contains a conductive material and seals the electrode body together with the exterior film, wherein the lid body has a lid main body and a convex portion that is integrally formed with the lid main body and protrudes from the lid main body in a direction opposite to the electrode body, and the convex portion has a hollow shape.

[0007] The energy storage device according to a second aspect of the present invention comprises an electrode body, an exterior film that wraps the electrode body, and a lid body that contains a conductive material and seals the electrode body together with the exterior film, and the lid body has a lid main body and a convex portion that is formed integrally with the lid main body and protrudes from the end of the lid main body in a direction opposite to the electrode body.

[0008] An electricity storage device according to a third aspect of the present invention is the electricity storage device according to the second aspect, wherein the thickness of the portion constituting the protrusion is in the range of 0.1 mm to 4.0 mm.

[0009] An electricity storage device according to a fourth aspect of the present invention is the electricity storage device according to the third aspect, wherein the thickness of the portion constituting the lid main body is in the range of 0.1 mm to 4.0 mm.

[0010] An energy storage device according to a fifth aspect of the present invention is an energy storage device according to any one of the first to fourth aspects, wherein the lid body has a base and a flange portion connected to the base and joined to the exterior film.

[0011] An electricity storage device according to a sixth aspect of the present invention is the electricity storage device according to any one of the first to fifth aspects, wherein the protrusion is connected to an edge of the lid body.

[0012] An electricity storage device according to a seventh aspect of the present invention is the electricity storage device according to any one of the first to fifth aspects, wherein the protrusion is formed at a distance from an edge of the lid body.

[0013] The lid body according to an eighth aspect of the present invention is a lid body used as an outer casing for an electricity storage device, and is composed of a conductive material. The lid body has a lid main body and a protrusion formed integrally with the lid main body and protruding from the lid main body, and the protrusion has a hollow shape.

[0014] A lid body according to a ninth aspect of the present invention is a lid body used as an outer casing for an electricity storage device, which is made of a conductive material and has a lid main body and a convex portion formed integrally with the lid main body and protruding from an end of the lid main body.

[0015] A tenth aspect of the present invention relates to a method for manufacturing an electricity storage device, the method comprising: an electrode assembly; an exterior film enclosing the electrode assembly; and a lid body containing a conductive material and sealing the electrode assembly together with the exterior film. The lid body has a lid body and a protrusion formed integrally with the lid body and protruding from the lid body in a direction away from the electrode assembly, the protrusion having a hollow shape. The method for manufacturing an electricity storage device includes a step of placing the lid body on the electrode assembly.

[0016] A method for manufacturing an electricity storage device according to an eleventh aspect of the present invention is a method for manufacturing an electricity storage device including an electrode assembly, an exterior film that wraps the electrode assembly, and a lid that contains a conductive material and seals the electrode assembly together with the exterior film. The lid has a lid main body and a protrusion that is formed integrally with the lid main body and protrudes from an end of the lid main body in a direction away from the electrode assembly. The method for manufacturing an electricity storage device includes a step of placing the lid main body on the electrode assembly.

[0017] According to the electricity storage device, the lid, and the method for manufacturing the electricity storage device of the present invention, it is possible to suitably output current.

[0018] 1A. A perspective view of an electricity storage device according to an embodiment. A diagram relating to a method for measuring the seal strength of a second sealed portion of the electricity storage device of FIG. 1. A cross-sectional view showing the layer structure of an exterior film included in the electricity storage device of FIG. 1. A diagram showing the exterior film included in the electricity storage device of FIG. 1 in an unfolded state. A perspective view of the rear side of a lid included in the electricity storage device of FIG. 1. A perspective view of the front side of the lid of FIG. 4. A cross-sectional view taken along line D6-D6 of FIG. 1A. A cross-sectional view taken along line D7-D7 of FIG. 1A. A flowchart showing an example of a manufacturing method of the electricity storage device of FIG. 1. A perspective view of the rear side of a lid included in an electricity storage device of a first modified example. A perspective view of the front side of the lid of FIG. 9. A cross-sectional view of a lid included in an electricity storage device of a second modified example. A perspective view of the front side of a lid included in an electricity storage device of a third modified example. A perspective view of the rear side of a lid included in an electricity storage device of a fourth modified example. A cross-sectional view of a lid included in an electricity storage device of a fifth modified example. A cross-sectional view of a lid included in an electricity storage device of a sixth modified example.

[0019] Hereinafter, an electricity storage device according to one 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.

[0020] [Embodiments] <1-1. Configuration of Electricity Storage Device> FIG. 1A is a plan view schematically illustrating an electricity storage device 10 according to an embodiment. FIG. 1B is a diagram illustrating a method for measuring the seal strength of a second sealed portion 100B of the electricity storage device 10 of FIG. 1A. FIG. 2 is a cross-sectional view illustrating the layer configuration of an exterior film 50 included in the electricity storage device 10 of FIG. 1A. FIG. 3 is a diagram illustrating the exterior film 50 included in the electricity storage device 10 of FIG. 1A in an unfolded state. FIG. 4 is a perspective view of the rear side of a lid body 60 included in the electricity storage device 10 of FIG. 1A. FIG. 5 is a perspective view of the front side of the lid body 60 of FIG. 4. FIG. 6 is a cross-sectional view taken along line D6-D6 in FIG. 1A. FIG. 7 is a cross-sectional view taken along line D7-D7 in FIG. 1A. In FIG. 1A, 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.

[0021] The energy storage device 10 includes an electrode assembly 20 including a current collector 30 and an exterior housing 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.

[0022] One end 31 of the current collector 30 (see FIG. 7) is connected to the lid 60 .

[0023] The exterior body 40 seals the electrode body 20. The exterior body 40 includes an exterior film 50 and a lid 60. The exterior film 50 wraps the electrode body 20. In the present embodiment, the exterior film 50 is wrapped around the electrode body 20. The lid 60 is disposed on the side of the electrode body 20 in the FB direction. In another example, the electrode body 20 may be housed inside an exterior film 50 configured in a cylindrical shape so that openings are formed at both ends in the FB direction, and the openings may be closed by the lid 60. In yet another example, the electrode body 20 connected to the lid 60 may be housed inside an exterior film 50 configured in a cylindrical shape so that openings are formed, and the openings may be closed by the lid 60.

[0024] For example, there is a method of forming a storage portion (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 storage portion using such a method. Attempting to form a deep storage portion (recess) by cold forming (for example, a forming depth of 15 mm) 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 exhibit 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.

[0025] 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; for example, it may not include the barrier layer 52. That is, the exterior film 50 may be made of any material that is flexible and easily bendable, 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 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.

[0026] The exterior film 50 may be composed of a laminate including at least a barrier layer 52 and a heat-sealable resin layer 53 in this order. In this laminate, the base layer 51 is an optional layer, and the side of the barrier layer 52 opposite to the heat-sealable resin layer 53 is the outermost layer, and the heat-sealable resin layer 53 is the innermost layer.

[0027] 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.

[0028] 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. 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.

[0029] 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. The barrier layer 52 preferably 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.

[0030] 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.

[0031] 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 to the aluminum alloy foil as needed. 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.

[0032] 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.

[0033] Specific examples of austenitic stainless steels that form the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] The lid body 60 has a lid main body 70, a protrusion 80, and a covering body 90 that covers a part of the lid main body 70. The lid body 60 can be manufactured, for example, by injection molding the covering body 90 onto the lid main body 70.

[0043] The lid main body 70 and the convex 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 and the convex 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 convex portion 80 can contain, in addition to the conductive material, a material other than the conductive material. The lid main body 70 and the convex portion 80 preferably have the corrosion-resistant coating described in connection with the barrier layer 52.

[0044] The conductive material constituting the lid main body 70 and the protrusion 80 is, for example, a metal material. The metal material constituting the lid main body 70 and the protrusion 80 is, for example, aluminum, aluminum alloy, nickel, copper, or a copper alloy. For example, when the electrode body 20 is a lithium-ion battery, the lid main body 70 and the protrusion 80 connected to the positive electrode are preferably made of aluminum or an aluminum alloy. The lid main body 70 and the protrusion 80 connected to the negative electrode are preferably made of nickel, copper, or a copper alloy. The material constituting the lid main body 70 and the protrusion 80 connected to the negative electrode may be nickel-plated copper. The material constituting the lid main body 70 and the protrusion 80 may include recycled metal material. The lid main body 70 has a base 71 and a flange 72.

[0045] 4 and 5 is, for example, a rectangular plate and has a first surface 71A and a second surface 71B. The first surface 71A faces the outside. The second surface 71B is the surface opposite to the first surface 71A. The second surface 71B faces the electrode body 20. The base 71 may have any shape, such as a cylinder, a prism, a rectangular parallelepiped, or a cube.

[0046] The flange portion 72 is covered by the cover 90. The flange portion 72 is frame-shaped and rises from the edge of the base 71. The flange portion 72 has a first flange portion 72A, a second flange portion 72B, and a third flange portion 72C. The first flange portion 72A forms the top surface of the lid main body 70. The first flange portion 72A extends in a first direction (in the present embodiment, the LR direction) in a front view of the lid main body 70. The second flange portion 72B and the third flange portion 72C are connected to the first flange portion 72A and form the side surfaces of the lid main body 70. The second flange portion 72B and the third flange portion 72C extend in a second direction (in the present embodiment, the UD direction) that intersects with the first direction in a front view of the lid main body 70. In the present embodiment, the first direction and the second direction are orthogonal in a front view of the lid main body 70. The first direction and the second direction do not have to be perpendicular to each other in a front view of the lid body 70. The fourth flange portion 72D forms the lower surface of the lid body 70. The fourth flange portion 72D extends in the first direction (the LR direction in this embodiment) in a front view of the lid body 70.

[0047] At least a portion of the surface 72X of the flange portion 72 is covered with the covering body 90. In this embodiment, the entire surface 72X of the flange portion 72 is covered with the covering body 90. An arbitrary location of the lid body 70 is connected to the end portion 31 of the current collector 30. In the example shown in FIG. 7 , the second surface 71B of the base 71 and the end portion 31 of the current collector 30 are connected.

[0048] The protrusion 80 is an element for outputting current to the outside and is connected to an external device. The protrusion 80 may be, for example, an element for fixing the electricity storage device 10. The protrusion 80 is formed integrally with the lid main body 70. That is, this embodiment does not include a configuration in which the lid main body 70 and the protrusion 80 are formed as separate bodies and joined by, for example, welding. Since poor joining between the lid main body 70 and the protrusion 80 does not occur during the manufacture of the lid body 60, the electricity storage device 10 can suitably output current to an external device. Furthermore, since the step of joining the lid main body 70 and the protrusion 80 is not required, the manufacturing method of the electricity storage device 10 can be simplified.

[0049] The protrusion 80 protrudes from the lid main body 70 in a direction opposite to the electrode assembly 20 (hereinafter referred to as the "outward direction"). The protrusion 80 preferably protrudes in the outward direction from an element that faces the electrode assembly 20, or an element that indirectly faces the electrode assembly 20 via an arbitrary member, among the elements that constitute the lid main body 70. In the present embodiment, the protrusion 80 protrudes in the outward direction from the base 71 of the lid main body 70. In a side view of the electricity storage device 10, the outward direction can be selected arbitrarily as long as it is a direction opposite to the electrode assembly 20. In the present embodiment, the outward direction coincides with the FB direction in a side view of the electricity storage device 10. The outward direction may also be a direction that intersects with the FB direction in a side view of the electricity storage device 10.

[0050] The shape of the protrusion 80 can be selected arbitrarily as long as it protrudes outward from the lid main body 70. In this embodiment, the protrusion 80 is a hollow block that protrudes outward from the base 71 of the lid main body 70. In cross section, the shape of the protrusion 80 is rectangular. The shape of the tip of the protrusion 80 may be angular, or may be rounded by applying a rounded edge. A space 80A is formed inside the protrusion 80.

[0051] The position where the protrusion 80 is formed in the UD direction can be selected arbitrarily. In the example shown in Fig. 5 etc., the protrusion 80 is formed approximately in the center in the UD direction. The protrusion 80 may be formed in a position closer to the first flange portion 72A or closer to the fourth flange portion 72D in the UD direction.

[0052] The width of the protrusion 80 in the LR direction can be selected arbitrarily. In the example shown in Fig. 5 etc., the protrusion 80 extends from one edge to the other edge of the base 71 in the LR direction. In the LR direction, the protrusion 80 may be formed with a gap between it and at least one of the one edge and the other edge of the base 71.

[0053] The length of the protrusion 80 in the external direction can be selected arbitrarily. From the viewpoint of easy connection to external devices, the length of the protrusion 80 in the external direction is preferably 0.5 mm or more, and more preferably 1.0 mm or more. From the viewpoint of configuring the power storage device 10 in a compact size, the length of the protrusion 80 in the external direction is preferably 30 mm or less, and more preferably 10 mm or less. A preferred range for the length of the protrusion 80 in the external direction is 0.5 mm or more and 30 mm or less, 0.5 mm or more and 10 mm or less, 1.0 mm or more and 30 mm or less, or 1.0 mm or more and 10 mm or less.

[0054] The number of protrusions 80 included in one lid body 60 can be selected arbitrarily. In the example shown in Fig. 5 etc., one lid body 60 has one protrusion 80. One lid body 60 may have two or more protrusions 80.

[0055] The lid body 70 and the protrusion 80 may be made of the same conductive material or different conductive materials, or at least one of the lid body 70 and the protrusion 80 may be made of a partially different conductive material.

[0056] The lid body 70 and the protrusion 80 configured as described above can be manufactured by, for example, cutting, grinding, electric discharge machining, laser machining, casting, rolling, sintering, powder metallurgy, 3D printing, press molding, sheet metal processing, or forging. The lid body 70 and the protrusion 80 are not limited to these methods and can be manufactured by any method.

[0057] The thickness HA of the portion constituting the lid main body 70 and the thickness HB of the portion constituting the protrusion 80 (both see FIG. 7 ) can be selected arbitrarily. From the viewpoint of easily manufacturing the lid main body 70 and the protrusion 80, the thicknesses HA and HB are preferably 0.1 mm or greater. On the other hand, if the volumes of the lid main body 70 and the protrusion 80 are large, heat from the heat seal may be absorbed by the lid main body 70 and the protrusion 80 when forming the second sealing section 100B described below, which may result in poor bonding of the second sealing section 100B. Furthermore, the process of forming the second sealing section 100B takes longer. Furthermore, if the volumes of the lid main body 70 and the protrusion 80 are large, the weight energy density of the power storage device 10 itself will be lower. Therefore, from the viewpoint of suitably forming the second sealing portion 100B and preventing a decrease in the weight energy density of the power storage device 10 itself, the thicknesses HA and HB are preferably 7.0 mm or less, more preferably 4.0 mm or less, even more preferably 3.0 mm or less, and even more preferably 2.0 mm or less. The preferred ranges for the thicknesses HA and HB are 0.1 mm or more to 7.0 mm, 0.1 mm or more to 4.0 mm or less, 0.1 mm or more to 3.0 mm or less, or 0.1 mm or more to 2.0 mm or less. The portions constituting the lid main body 70 and the protrusion 80 may have partially different thicknesses. When the thicknesses of the portions constituting the lid main body 70 and the protrusion 80 are partially different, the thicknesses HA and HB are the maximum thicknesses, respectively.

[0058] The cover 90 shown in FIGS. 4, 5, and 6 has a lid seal portion 91. The lid seal portion 91 is heat-sealed to the heat-fusible resin layer 53 of the exterior film 50. The lid seal portion 91 and the exterior film 50 may be joined by any method other than heat sealing, such as welding. Specific welding methods include laser welding, ultrasonic welding, and other methods. The lid seal portion 91 includes a first seal surface 91A, a second seal surface 91B, a third seal surface 91C, and a fourth seal surface 91D. The first seal surface 91A forms the top surface of the lid 60. The first seal surface 91A is formed on the first flange portion 72A. The first seal surface 91A extends in a first direction (the LR direction in this embodiment) when viewed from the front of the lid 60. The second seal surface 91B and the third seal surface 91C are connected to the first seal surface 91A and form the side surfaces of the lid 60. The second seal surface 91B is formed on the second flange portion 72B. The third seal surface 91C is formed on the third flange portion 73C. The second seal surface 91B and the third seal surface 91C extend in a second direction (UD direction in this embodiment) intersecting the first direction in a front view of the lid body 60. In this embodiment, the first direction and the second direction are perpendicular to each other in a front view of the lid body 60. The first direction and the second direction do not have to be perpendicular to each other in a front view of the lid body 60. The fourth seal surface 91D forms the underside of the lid body 60. The fourth seal surface 91D extends in the first direction (LR direction in this embodiment) in a front view of the lid body 60. The fourth seal surface 91D is formed on the fourth flange portion 72D.

[0059] The lid seal portion 91 further includes boundaries 92, 93, 94, and 95. The boundary 92 is the boundary between the first seal surface 91A and the second seal surface 91B. The boundary 93 is the boundary between the first seal surface 91A and the third seal surface 91C. The boundary 94 is the boundary between the fourth seal surface 91D and the second seal surface 91B. The boundary 95 is the boundary between the fourth seal surface 91D and the third seal surface 91C. The shapes of the boundaries 92 to 95 may be angular, or may be rounded by applying a rounding process. In this embodiment, the boundaries 92 to 95 are angular.

[0060] The covering body 90 is made of a resin material. Here, "made of a resin material" means that, when the entire material constituting the covering body 90 is taken as 100% by mass, the resin material content 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 covering body 90 can contain materials other than the resin material in addition to the resin material.

[0061] 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 covering 90 may be molded using any molding method.

[0062] The resin material contained in the material constituting the coating 90 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 90 preferably contains multiple types of amide-based lubricants. Furthermore, the resin material contained in the material constituting the coating 90 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 90 may be a polyolefin resin to which a propylene-based elastomer having a melting point higher than 150°C has been added.

[0063] 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.

[0064] 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.

[0065] 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 covering 90 against temperature changes can be improved.

[0066] The melt mass flow rate of the resin material contained in the material constituting the coating 90 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.

[0067] The lid 60 may be bonded to the exterior film 50 via an adhesive film instead of the covering 90. Any adhesive film can be selected as long as it can bond the exterior film 50 and the lid 60 together. The adhesive film is preferably a laminated film having at least a heat-sealable resin layer, a heat-resistant substrate layer, and a heat-sealable resin layer in this order. The specifications for the heat-sealable resin layer of the adhesive film are the same as those for the heat-sealable resin layer 53. The materials constituting the heat-sealable resin layers on both sides of the adhesive film may be the same or different, and are appropriately selected according to the materials constituting the heat-sealable resin layer 53 of the exterior film 50 and the material constituting the lid 60. The material constituting the heat-sealable resin layer of the adhesive film on the side bonded to the lid 60 is preferably an acid-modified polyolefin resin graft-modified with an acid such as maleic anhydride. The heat-sealable resin layer of the adhesive film on the side that is bonded to the exterior film 50 is preferably made of the same type of material as the material that constitutes the heat-sealable resin layer 53 of the exterior film 50 .

[0068] The heat-resistant substrate layer may be any film made of a heat-resistant resin, such as a non-stretched or stretched film of polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polymethylpentene (registered trademark), polyacetal cyclic polyolefin, polyethylene, polypropylene, etc. Polyethylene terephthalate is particularly preferred because it is inexpensive and has high strength.

[0069] The adhesive film preferably has adhesive properties. When the second sealing portion 100B described below is formed with the adhesive film disposed between the exterior film 50 and the lid 60, the adhesive film is less likely to shift position relative to the lid 60 and the exterior film 50. By incorporating a tackifying resin into the heat-sealable resin layer of the adhesive film, adhesive properties can be imparted to the adhesive film. Examples of the tackifying resin include amorphous polyolefins. Examples of amorphous polyolefins include amorphous polypropylene and copolymers of amorphous propylene and other α-olefins. The content of the tackifying resin relative to the base material constituting the heat-sealable resin is preferably 10 to 20% by weight or less.

[0070] When the lid body 60 is 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 it. From another perspective, when the lid body 60 is plate-shaped, it is preferable that the lid seal portion 91 of the lid body 60 have a certain width in the FB direction so that the lid seal portion 91 of the lid body 60 and the exterior film 50 can be heat-sealed appropriately when forming the second sealing portion 100B described below. The minimum width of the lid seal portion 91 of the lid body 60 is, for example, 1.0 mm, more preferably 3.0 mm, and even more preferably 4.0 mm. The maximum width of the lid seal portion 91 of the lid body 60 is, for example, 20 mm, more preferably 15 mm, and even more preferably 10 mm. The maximum width of the lid seal portion 91 of the lid body 60 may be 20 mm or more. Preferred width ranges for the lid seal portion 91 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. In this embodiment, when the lid body 60 is described as plate-shaped, this does not include embodiments in which the lid body 60 is composed solely of a film defined by the JIS (Japanese Industrial Standards) [Packaging Terminology] standard. Note that the width of the lid seal portion 91 of the lid body 60 may vary depending on the location. When the width of the lid seal portion 91 of the lid body 60 varies depending on the location, the width of the lid seal portion 91 of the lid body 60 is the width of the widest portion.

[0071] In this embodiment, the first sealing portion 100A is formed by wrapping the exterior film 50 around the electrode body 20 and heat-sealing the opposing surfaces of the exterior film 50 (heat-fusible resin layer 53).

[0072] The first sealed portion 100A is formed by heat-sealing a portion of the exterior film 50 including the first edge 50A and a portion of the exterior film 50 including the second edge 50B shown in FIG. 3 . The first sealed portion 100A extends in the longitudinal direction of the exterior body 40. The position at which the first sealed portion 100A is formed on the exterior body 40 can be selected arbitrarily. In this embodiment, the base 70X of the first sealed portion 100A is preferably located on the edge 43 at the boundary between the first surface 41 and the second surface 42 of the exterior body 40. The first surface 41 has a larger area than the second surface 42. The base 100AX of the first sealed portion 100A may be located on any surface of the exterior body 40. In this embodiment, the first sealed portion 100A protrudes outward beyond the electrode assembly 20 in a plan view. The first sealed portion 100A may be folded, for example, toward the second surface 42 or the first surface 41 of the exterior body 40.

[0073] In this embodiment, the second sealing portion 100B (lid sealing portion 100B) is formed by heat-sealing the heat-fusible resin layer 53 of the exterior film 50 and the lid seal portion 91 of the lid body 60. Hereinafter, the seal strength between the heat-fusible resin layer 53 of the exterior film 50 and the lid seal portion 91 of the lid body 60 may be referred to as the seal strength (bonding strength) of the second sealing portion 100B. Note that the seal strength of the second sealing portion 100B is the seal strength between the heat-fusible resin layer 53 and the lid body 60 at the long side portion of the lid seal portion 91, i.e., the lid seal portion 91 extending in the LR (width) direction in FIG. 1A .

[0074] The seal strength of the second sealing portion 100B is measured as follows. First, a slit is formed in the portion of the exterior film 50 that constitutes the first surface 41 of the exterior body 40, forming three strip-shaped members 41X, 41Y, and 41Z (see the two-dot chain lines in FIG. 1B ) aligned in the LR direction. The width of the three strip-shaped members 41X, 41Y, and 41Z in the LR direction is 15 mm. The ends of the strip-shaped members 41X, 41Y, and 41Z are joined to the lid body 60 in the second sealing portion 100B. The length of the lid body 60 in the LR direction is 45 mm or more. Next, the end of each of the strip-shaped members 41X, 41Y, and 41Z opposite the end joined to the lid body 60 is pulled upward in the UD direction (away from the first surface 41B), thereby measuring the seal strength of each of the strip-shaped members 41X, 41Y, and 41Z. The distance between the zippers in the UD direction is 10 mm. The seal strengths of the strip-shaped members 41X, 41Y, and 41Z are the peak values ​​of their respective seal strengths. In this embodiment, the seal strength of the second sealing portion 100B is the average value of the seal strengths of the strip-shaped members 41X, 41Y, and 41Z. When the LR length of the lid body 60 is less than 45 mm, three strip-shaped members with an arbitrary width X mm, less than 15 mm, are formed, and the seal strengths of the three strip-shaped members are measured using the same method as when the LR length of the lid body 60 is 45 mm or more. The obtained seal strengths are each divided by the arbitrary width X mm and multiplied by 15 to convert them to the seal strengths of the three strip-shaped members at a 15 mm width. The seal strength of the second sealing portion 100B is the average value of the seal strengths of the three strip-shaped members converted to a 15 mm width. In addition, when the lid body 60 is divided into multiple parts including long and short sides, the sealing strength of the second sealing portion 100B is the sealing strength of the long side portion of the lid seal portion 91 of the multiple parts.

[0075] From the viewpoint of suitably maintaining the state in which the electrode assembly 20 is sealed by the exterior body 40, the seal strength of the second sealing unit 100B is preferably 40 N / 15 mm or more, more preferably 50 N / 15 mm or more, even more preferably 60 N / 15 mm or more, even more preferably 70 N / 15 mm or more, and even more preferably 85 N / 15 mm or more. When the seal strength of the second sealing unit 100B is 40 N / 15 mm or more, the state in which the electrode assembly 20 is sealed by the exterior body 40 is suitably maintained even after the power storage device 10 has been used for, for example, several years (less than 10 years). When the seal strength of the second sealing unit 100B is 85 N / 15 mm or more, the state in which the electrode assembly 20 is sealed by the exterior body 40 is suitably maintained even after the power storage device 10 has been used for, for example, 10 years or more. The seal strength of the second sealing unit 100B is preferably 300 N / 15 mm or less. A preferred range of the seal strength of the second sealing portion 100B is 40N / 15mm to 300N / 15mm, 50N / 15mm to 300N / 15mm, 60N / 15mm to 300N / 15mm, 70N / 15mm to 300N / 15mm, or 85N / 15mm to 300N / 15mm.

[0076] In this embodiment, the lid body 60 preferably has a protrusion 96 protruding from the lid seal portion 91 to prevent a gap from forming between the exterior film 50 and the lid body 60. The protrusion 96 may be formed integrally with the cover 90, or may be formed separately from the cover 90 and joined to the cover 90. In this embodiment, the protrusion 96 is formed integrally with the cover 90. The position at which the protrusion 96 is formed in the lid seal portion 91 can be selected arbitrarily. A gap between the exterior film 50 and the lid body 60 is likely to form, for example, between the base 100AX of the first sealing portion 100A and the lid body 60. In particular, when the base 100AX of the first sealing portion 100A is located between the boundary 92 and boundary 95 of the lid body 60, the resin filling ability between the base 100AX of the first sealing portion 100A and the lid body 60 is likely to decrease. For this reason, the protrusion 96 is preferably formed in the lid seal portion 91 at a location where the root 100AX of the first sealing portion 100A is located. In this embodiment, the root 100AX of the first sealing portion 100A is located at the boundary 92 of the lid body 60. For this reason, the protrusion 96 is preferably formed in the lid seal portion 91 at the boundary 92. In this embodiment, the first sealing portion 100A is sealed with the protrusion 96 sandwiched between them. Note that the protrusion 96 may be formed on at least one of the first seal surface 100AA, the second seal surface 100AB, the third seal surface 100AC, the fourth seal surface 100AD, the boundary 93, the boundary 94, and the boundary 95.

[0077] The shape of the protrusion 96 can be selected arbitrarily. In this embodiment, the shape of the protrusion 96 is plate-like. The thickness of the protrusion 96 can be selected arbitrarily. In this embodiment, the thickness of the protrusion 96 becomes thinner with increasing distance from the boundary 92. In other words, the protrusion 96 has a tapered shape with increasing distance from the boundary 92. The thickness of the protrusion 96 may be constant, or may increase with increasing distance from the boundary 92.

[0078] The direction in which the protrusion 96 extends can be selected arbitrarily. In the present embodiment, the protrusion 96 extends along a first direction (in the present embodiment, the LR direction). The protrusion 96 may extend along a second direction (in the present embodiment, the UD direction). The protrusion 96 may extend in a third direction that intersects with the first direction (in the present embodiment, the LR direction) and the second direction (in the present embodiment, the UD direction) when the lid 60 is viewed from the front.

[0079] The length of the protrusion 96 can be selected arbitrarily within a range equal to or less than the length of the first sealing portion 100A. For example, the length of the protrusion 96 may be substantially equal to the length of the first sealing portion 100A, or may be 30% to 50% of the length of the first sealing portion 100A.

[0080] 8 is a flowchart showing an example of a method for manufacturing the power storage device 10. The method for manufacturing the power 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 power 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 method for manufacturing the power storage device 10 defined for convenience, and do not necessarily refer to the order of the steps. The order of the first step to the sixth step can be changed as desired as long as it is not technically inconsistent.

[0081] In the first process of step S11 , the manufacturing device manufactures the lid body 60 .

[0082] The second process of step S12 is carried out after the first process. In the second process, the manufacturing apparatus arranges a pair of lid bodies 60 on the sides of the electrode body 20 in the FB direction.

[0083] The third step of step S13 is performed after the second step. In the second step, the manufacturing apparatus joins the current collector 30 and the lid 60 together.

[0084] The fourth step of step S14 is performed after the third step. In the fourth step, 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 using 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 are formed at both ends in the FB direction, and after the current collector 30 and the lid 60 are joined, the opening may be closed by the lid 60. In yet another example, the electrode body 20 connected to the lid 60 may be housed inside an exterior film 50 configured in a cylindrical shape so that openings are formed at both ends in the FB direction, and the opening may be closed by the lid 60.

[0085] The fifth step of step S15 is performed after the fourth step. In the fifth step, the manufacturing apparatus heat-seals the exterior film 50 and the lid 60 together to form the second sealed portion 110B.

[0086] The sixth step of step S16 is performed before or after the fifth step. In the sixth step, the manufacturing apparatus forms the first sealed portion 100A by heat-sealing the heat-sealable resin layer 53 in the portion including the first edge 50A of the exterior film 50 and the heat-sealing the heat-sealable resin layer 53 in the portion including the second edge 50B while restricting the movement of the electrode body 20 and the lid body 60 and applying tension to the exterior film 50.

[0087] <1-3. Functions and Effects of the Electricity Storage Device> In the electricity storage device 10, the lid main body 70 and the protrusion 80 are integrally formed, so there is no bonding failure between the lid main body 70 and the protrusion 80. Therefore, the electricity storage device 10 can suitably output current to an external device.

[0088] [2. Modifications] The above-described embodiments are examples of possible forms of the electricity storage device, lid, 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, lid, 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.

[0089] <2-1. First Modification> In the above embodiment, the shape of the convex portion 80 can be changed. Fig. 9 is a perspective view of the rear side of the lid 160 provided in the electricity storage device 10 of the first modification. Fig. 10 is a perspective view of the front side of the lid 160 in Fig. 9. Note that the cover 90 is omitted in Figs. 9 and 10.

[0090] The lid body 160 has a lid main body 170 and a protrusion 180 formed integrally with the lid main body 170. The lid main body 170 has the same configuration as the lid main body 70. The protrusion 180 may be formed with a gap between one edge and the other edge of the base 71 in at least one of the LR direction and the UD direction. A space 180A is formed inside the protrusion 180. In other words, the protrusion 180 is hollow. The lid main body 170 and the protrusion 180 can also be manufactured by the manufacturing method exemplified in the embodiment. Note that the protrusion 180 can have any shape, such as a cylindrical shape, as long as it is hollow.

[0091] 2-2. Second Modification The cross-sectional shape of the convex portion 80 can be selected arbitrarily. FIG. 11 is a cross-sectional view of a lid body 260 included in an electricity storage device 10 according to a second modification. Note that the cover 90 is omitted from FIG. 11 . The lid body 260 has a lid main body 270 and a convex portion 280 formed integrally with the lid main body 270. The convex portion 280 may have a triangular shape in cross-section. A space 280A is formed inside the convex portion 280. The lid main body 270 and the convex portion 280 can be manufactured, for example, by the manufacturing method exemplified in the embodiment.

[0092] <2-3. Third Modification> In the above embodiment, at least a part of the flange portion 72 of the lid 60 may be omitted. Fig. 12 is a perspective view of the front side of a lid 360 provided in an electricity storage device 10 of the third modification. Note that the cover 90 is omitted in Fig. 12.

[0093] The lid body 360 has a lid main body 370 and a protrusion 380 formed integrally with the lid main body 370. The lid main body 370 has a shape in which the second flange portion 72B and the third flange portion 72C are omitted from the lid main body 70 of the embodiment. Openings 370Y are formed at both ends of the lid main body 370 in the LR direction.

[0094] The protrusion 380 is, for example, a hollow block shape, with a space 380A formed therein. Openings 380Y are formed at both ends of the protrusion 380 in the LR direction. The lid body 370 and the protrusion 380 can be manufactured by the manufacturing method exemplified in the embodiment. To facilitate bonding of the lid body 360 to the exterior film 50, a resin molded product for bonding to the exterior film 50 is preferably disposed so as to fill at least a portion of the openings 370Y and 380Y. The resin molded product may be insert-molded into the lid body 370, for example. The lid body 370 may omit the first flange 72A and the fourth flange 72D in addition to the second flange 72B and the third flange 72C.

[0095] 2-4. Fourth Modification In the above embodiment, the position of the protrusion 80 in the UD direction can be changed as desired. Fig. 13 is a perspective view of the front side of a lid main body 470 included in an electricity storage device 10 according to a fourth modification. Note that the cover 90 is omitted from Fig. 13.

[0096] The lid body 460 has a lid main body 470 and a protrusion 480 formed integrally with the lid main body 470. The lid main body 470 has a shape similar to that of the lid main body 70 of the embodiment, except that the second flange portion 72B, the third flange portion 72C, and the fourth flange portion 72D are omitted.

[0097] The protrusion 480 is, for example, a solid plate-like member. The protrusion 480 protrudes outward in the UD direction from the lower end of the base 71. The lid body 470 and the protrusion 480 can be manufactured by the manufacturing method exemplified in the embodiment.

[0098] <2-5. Fifth Modification> In the fourth modification, the convex portion 480 may protrude outward in the UD direction from the upper end of the base portion 71. Fig. 14 is a cross-sectional view of a lid 560 provided in an electricity storage device according to a fifth modification, which is a further modification of the electricity storage device 10 according to the fourth modification. Note that the cover 90 is omitted in Fig. 14.

[0099] The lid body 560 has a lid main body 570 and a protrusion 580 formed integrally with the lid main body 570. The protrusion 580 protrudes outward from the upper end of the base 71 in the UD direction. The protrusion 580 is, for example, a hollow block shape. The shape of the protrusion 580 in cross section is rectangular. The shape of the protrusion 580 in cross section may be circular, elliptical, triangular, or polygonal. A space 580A is formed inside the protrusion 580. The lid main body 570 and the protrusion 580 can be manufactured by the manufacturing method exemplified in the embodiment.

[0100] 2-6. Sixth Modification In the fifth modification, the shape of the convex portion 580 can be changed. Fig. 15 is a cross-sectional view of a lid 660 provided in an electricity storage device according to a sixth modification, which is a further modification of the electricity storage device 10 according to the fifth modification. Note that the cover 90 is omitted from Fig. 15.

[0101] The lid body 660 has a lid main body 670 and a protrusion 680 formed integrally with the lid main body 670. The protrusion 680 protrudes outward from the upper end of the base 71 in the UD direction. The protrusion 680 is a solid plate. The protrusion 680 has a first portion 681, a second portion 682, and a third portion 683. The first portion 681 is connected to the base 71 and extends, for example, in the FB direction. The second portion 682 is connected to the first portion 681 and extends, for example, in the UD direction. The third portion 683 is connected to the second portion 682 and extends, for example, in the FB direction. The lid main body 670 and the protrusion 680 can be manufactured by the manufacturing method exemplified in the embodiment.

[0102] <2-7. Seventh Modification> In the above embodiment, the exterior film 50 of the power storage device 10 may protrude outward beyond at least one of the two lid bodies 60 in the FB direction. 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 like a Goebel-top pouch or a brick pouch. In the eighth modification, the length of the convex portion 80 in the outward direction is preferably long enough to be exposed from the portion of the exterior film 50 that protrudes outward beyond the lid body 60.

[0103] <2-8. Eighth 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. The portion of the exterior film 50 that protrudes outward beyond the electrode body 20 may be folded like a Goebel-top pouch or a brick pouch.

[0104] 2-9. Ninth 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.

[0105] 10: Electricity storage device 20: Electrode body 30: Current collector 40: Exterior body 50: Exterior film 60: Lid body 70: Lid body 72: Flange portion 80: Convex portion 160: Lid body 170: Lid body 180: Convex portion 260: Lid body 270: Lid body 280: Convex portion 360: Lid body 370: Lid body 380: Convex portion 460: Lid body 470: Lid body 480: Convex portion 560: Lid body 570: Lid body 580: Convex portion 660: Lid body 670: Lid body 680: Convex portion 760: Lid body 770: Lid body 780: Convex portion

Claims

1. An electricity storage device comprising: an electrode body; an exterior film wrapping the electrode body; and a lid body containing a conductive material and sealing the electrode body together with the exterior film, wherein the lid body has a lid main body and a convex portion formed integrally with the lid main body and protruding from the lid main body in a direction opposite to the electrode body, the convex portion having a hollow shape.

2. An electricity storage device comprising: an electrode body; an exterior film that wraps the electrode body; and a lid body that contains a conductive material and seals the electrode body together with the exterior film, wherein the lid body has a lid main body and a convex portion that is formed integrally with the lid main body and protrudes from an end of the lid main body in a direction opposite to the electrode body.

3. The electricity storage device according to claim 2, wherein the thickness of the portion constituting the protrusion is in the range of 0.1 mm to 4.0 mm.

4. The electricity storage device according to claim 3, wherein the thickness of the portion constituting the lid body is in the range of 0.1 mm to 4.0 mm.

5. The electricity storage device according to any one of claims 1 to 4, wherein the lid body has a base and a flange portion connected to the base and joined to the exterior film.

6. The electricity storage device according to any one of claims 1 to 4, wherein the protrusion is connected to an edge of the lid body.

7. The electricity storage device according to any one of claims 1 to 4, wherein the protrusion is formed with a gap between it and the edge of the lid body.

8. A lid body used as an exterior body for an electricity storage device, the lid body being made to contain a conductive material and having: a lid main body; and a protrusion formed integrally with the lid main body and protruding from the lid main body, the protrusion having a hollow shape.

9. A lid body used as an exterior body for an electricity storage device, the lid body being formed containing a conductive material and having: a lid main body; and a protrusion formed integrally with the lid main body and protruding from an end portion of the lid main body.

10. A method for manufacturing an electricity storage device, the electricity storage device comprising: an electrode body; an exterior film wrapping the electrode body; and a lid body containing a conductive material and sealing the electrode body together with the exterior film, the lid body having a lid main body and a convex portion formed integrally with the lid main body and protruding from the lid main body in a direction opposite to the electrode body, the convex portion having a hollow shape, the method for manufacturing an electricity storage device comprising the step of placing the lid body on the electrode body.

11. A method for manufacturing an electricity storage device, the electricity storage device comprising: an electrode body; an exterior film wrapping the electrode body; and a lid body containing a conductive material and sealing the electrode body together with the exterior film, the lid body having a lid main body and a convex portion formed integrally with the lid main body and protruding from an end of the lid main body in a direction opposite to the electrode body, the method for manufacturing an electricity storage device comprising the step of positioning the lid body relative to the electrode body.

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