Power storage device, lid, covering body and method for manufacturing power storage device

Abstract

To provide a power storage device capable of being manufactured using a variety of procedures, a lid used in the power storage device, a covering body constituting the lid, and a method for manufacturing the power storage device.SOLUTION: A power storage device includes an electrode body and an exterior body for sealing the electrode body. The exterior body has an exterior film for wrapping the electrode body, and a lid for sealing the electrode body together with the exterior film. The lid has: a lid body comprising a metal material; and a covering body bonded to the exterior film and covering at least a part of an edge of the lid body.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device, a lid, a cover, and a method for manufacturing an electricity storage device. [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-described electricity storage device, the electrode body and the lid body are connected to each other, and then the electrode body and the lid body are wrapped in an exterior film. In the above-described electricity storage device, the electrode body is sealed at the stage when the electrode body and the lid body are wrapped in the exterior film, and therefore the steps of the manufacturing method are limited.

[0005] An object of the present invention is to provide an electricity storage device that can be manufactured by a variety of procedures, a lid used in this electricity storage device, a covering that constitutes this lid, and a method for manufacturing this electricity storage device. [Means for solving the problem]

[0006] The energy storage device according to a first aspect of the present invention comprises an electrode body and an exterior body that seals the electrode body, the exterior body having an exterior film that wraps the electrode body and a lid body that seals the electrode body together with the exterior film, and the lid body having a lid main body that contains a metal material and a covering body that is joined to the exterior film and covers at least a portion of the lid main body.

[0007] An electricity storage device according to a second aspect of the present invention is the electricity storage device according to the first aspect, wherein the covering body has a main body portion containing a metal material.

[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 volume of the main body is smaller than the volume of the lid main body.

[0009] An energy storage device according to a fourth aspect of the present invention is an energy storage device according to any one of the first to third aspects, wherein the covering body has a lid seal portion that is joined to the exterior film, and a protrusion that protrudes from the lid seal portion and defines a portion that covers the edge of the lid main body.

[0010] An electricity storage device according to a fifth aspect of the present invention is the electricity storage device according to the second or third aspect, wherein the cover further has a joint that covers at least a part of the edge of the main body.

[0011] An electricity storage device according to a sixth aspect of the present invention is the electricity storage device according to the fifth aspect, wherein the joint is a resin molded product.

[0012] An electricity storage device according to a seventh aspect of the present invention is the electricity storage device according to the fifth aspect, wherein the bonding portion is an adhesive film that can be bonded to metal materials and resin materials.

[0013] An electricity storage device according to an eighth aspect of the present invention is the electricity storage device according to the fifth aspect, wherein the joint is an adhesive.

[0014] A lid body according to a ninth aspect of the present invention is a lid body used as an exterior body for an electricity storage device, and comprises a lid body comprising a metal material, and a covering body joined to an exterior film constituting the exterior body and covering at least a portion of the edge of the lid body.

[0015] A covering according to a tenth aspect of the present invention is a covering constituting a lid used as an exterior body for an electricity storage device, the lid having a lid body comprising a metal material, the covering being joined to an exterior film constituting the exterior body and configured to cover at least a portion of the edge of the lid body.

[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 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 body sealing the electrode assembly together with the exterior film, the lid body having a lid main body containing a metal material; and a covering body joined to the exterior film and covering at least a portion of the lid main body. The method for manufacturing an electricity storage device includes a film bonding step of bonding the exterior film and the covering body, and a closing step, which is carried out after the film bonding step, of bonding the covering body and the lid main body. [Effects of the Invention]

[0017] According to the electricity storage device, lid, cover, and method for manufacturing an electricity storage device of the present invention, the electricity storage device can be manufactured by a variety of procedures. [Brief explanation of the drawings]

[0018] [Figure 1A] FIG. 1 is a perspective view of an electricity storage device according to an embodiment. [Figure 1B] 1B is a diagram relating to a method for measuring the seal strength of the second sealing portion of the electricity storage device in FIG. 1A. FIG. [Figure 2] 1B is a cross-sectional view showing an example of a layer structure of an exterior film included in the electricity storage device of FIG. 1A. [Figure 3]FIG. 1B is a diagram showing the state in which the exterior film provided on the electricity storage device of FIG. 1A is unfolded. [Figure 4A] 1B is a perspective view of a main body of a cover included in the electricity storage device of FIG. 1A. FIG. [Figure 4B] FIG. 4B is a cross-sectional view taken along line D4B-D4B in FIG. 4A. [Figure 5] 1B is a perspective view of a lid body of the lid body included in the electricity storage device of FIG. 1A. FIG. [Figure 6] FIG. 1B is a front view of the electricity storage device of FIG. 1A. [Figure 7] 1B is a cross-sectional view taken along line D7-D7 in FIG. 1A. [Figure 8] 1B is a flowchart showing an example of a method for manufacturing the electricity storage device of FIG. 1A. [Figure 9] 1B is a flowchart showing another example of a method for manufacturing the electricity storage device of FIG. 1A. DETAILED DESCRIPTION OF THE INVENTION

[0019] 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.

[0020] [1. Embodiment] <1-1. Configuration of the power storage device> FIG. 1A is a perspective view schematically showing an electricity storage device 10 of an embodiment. FIG. 1B is a diagram relating to a method for measuring the seal strength of a second sealing portion 92 of the electricity storage device 10 of FIG. 1. FIG. 2 is a cross-sectional view showing an example of the layer structure of an exterior film 50 included in the electricity storage device 10 of FIG. 1A. FIG. 3 is a view showing the exterior film 50 included in the electricity storage device 10 of FIG. 1A in an unfolded state. FIG. 4A is a perspective view of a main body 70A of a covering body 70 included in the electricity storage device of FIG. 1A. FIG. 4B is a cross-sectional view taken along line D4B-D4B in FIG. 4A. FIG. 5 is a perspective view of a lid main body 80 included in the electricity storage device 10 of FIG. 1A. FIG. 6 is a front view of the electricity storage device 10 of FIG. 1A. FIG. 7 is a cross-sectional view taken along line D7-D7 in FIG. 1. 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 figures.

[0021] The electricity 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 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, metal-air battery, polycation 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] 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 so as to form a pair of openings 40A. In the present embodiment, the exterior film 50 is wrapped around the electrode assembly 20 so as to form the pair of openings 40A. Note that the electrode assembly 20 may be housed inside the exterior film 50 configured in a cylindrical shape so as to form the pair of openings 40A, 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 the present embodiment, the pair of first surfaces 41A, 41B are substantially the same size. In the present embodiment, the pair of second surfaces 42A, 42B are substantially the same size. The pair of first surfaces 41A, 41B have a larger area than the pair of second surfaces 42A, 42B. The pair of lid bodies 60 are respectively disposed on the sides of the electrode body 20 so as to close the pair of openings 40A.

[0023] 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.

[0024] 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. Note that the exterior film 50 does not need 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 flexible and easily bendable material, such as a resin film. Note that the exterior film 50 is preferably 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 assembly 20 and the lid 60 by joining the outermost and innermost layers.

[0025] 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.

[0026] The substrate layer 51 included in the exterior film 50 is a layer that imparts heat resistance to the exterior film 50 and prevents pinholes from forming 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 prevented. Furthermore, from the viewpoint of increasing the tensile elongation of the exterior film 50, the stretched polyester resin layer is preferably a biaxially stretched polyester resin layer, and the stretched polyamide resin layer is preferably a biaxially stretched polyamide resin layer. Furthermore, from the viewpoint of excellent puncture strength or impact strength, the stretched polyester resin layer is more preferably a biaxially stretched polyethylene terephthalate (PET) film, and the stretched polyamide resin layer is more preferably a biaxially stretched nylon (ONy) film. The substrate layer 51 may be composed of both a stretched polyester resin layer and a stretched polyamide resin layer. The thickness of the base layer 51 is preferably, for example, 5 to 300 μm, and more preferably 5 to 150 μm, from the viewpoint of film strength.

[0027] The barrier layer 52 is a layer that prevents at least moisture from penetrating. The barrier layer 52 is bonded to the base 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. Other examples of the barrier layer 52 include resin films 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.

[0028] In the barrier layer 52, the layer made of the aforementioned metallic material may contain recycled metallic material. Examples of recycled metallic 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 solely of recycled material, or may be made of a mixture of recycled and virgin material. Note that recycled metallic material refers to metallic material that has been made reusable by collecting, isolating, and refining various products used in the market or waste from manufacturing processes. Furthermore, virgin metallic material refers to new metallic material refined from natural metallic resources (raw materials) and is not recycled material.

[0029] From the viewpoint of improving the formability or conformability of the exterior film 50, the aluminum alloy foil is preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy. From the viewpoint of further improving the formability or conformability, an iron-containing aluminum alloy foil is preferred. In the iron-containing aluminum alloy foil (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass. By having an iron content of 0.1% by mass or more, an exterior film 50 with better formability can be obtained. By having an iron content of 9.0% by mass or less, an exterior film 50 with better flexibility can be obtained. Furthermore, silicon, magnesium, copper, manganese, etc. may be added as necessary. Furthermore, softening can be achieved by annealing or the like. From the viewpoint of improving the mechanical strength of the exterior film 50, the aluminum alloy foil is more preferably a hard aluminum alloy foil made of, for example, a work-hardened aluminum alloy. Examples of hard aluminum alloy foils include aluminum alloy foils having a composition 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.

[0030] 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.

[0031] 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.

[0032] 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 9 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 an 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.

[0033] 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 using 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 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 barrier layer 52 has a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer 52.

[0034] The corrosion-resistant coating prevents delamination between the barrier layer 52 (e.g., aluminum alloy foil) and the base 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 particularly 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 base layer 51 and the barrier layer 52 during heat sealing and between the base layer 51 and the barrier layer 52 during molding.

[0035] 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 viewpoints 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.

[0036] 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 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.

[0037] 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.

[0038] When the buffer layer is made of rubber, the lower limit of the buffer layer thickness is preferably 0.5 mm. When the buffer layer is made of rubber, the upper limit of the buffer layer thickness 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 buffer layer thickness is 0.5 mm to 10 mm, 0.5 mm to 5 mm, or 0.5 mm to 2 mm.

[0039] 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.

[0040] The lid body 60 has a cover body 70 and a lid main body 80 .

[0041] The cover 70 has a main body portion 70A and a joint portion 70B. The main body portion 70A has a shape similar to a hollow rectangular parallelepiped, for example. A space 79 is formed inside the main body portion 70A. The material constituting the main body portion 70A can be selected arbitrarily. From the viewpoint of easy joining to the lid body 80, the main body portion 70A is preferably composed of a metal material. Here, "composed of a metal material" means that, when the entire material constituting the main body portion 70A is taken as 100% by mass, the content of the metal 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 main body portion 70A can contain materials other than metal materials in addition to metal materials. The metal material constituting the main body portion 70A can be selected arbitrarily. The metal material constituting the main body portion 70A can be, for example, aluminum, an aluminum alloy, nickel, copper, or a copper alloy. For example, when the electrode body 20 is a lithium ion battery, the main body 70A connected to the positive electrode is preferably made of aluminum or an aluminum alloy. The main body 70A connected to the negative electrode is preferably made of nickel, copper, or a copper alloy. The material constituting the main body 70A connected to the negative electrode may be copper plated with nickel. The material constituting the main body 70A may contain recycled metal materials. In this embodiment, the main body 70A is made only of metal materials. Because the main body 70A is made of a metal material, it also functions as an electrode terminal. This simplifies the configuration of the electricity storage device 10.

[0042] When the main body portion 70A is made of a metal material, it is preferable that the main body portion 70A has a corrosion-resistant coating as described for the barrier layer 52.

[0043] In another example, main body portion 70A may be configured to include a resin material. Here, "configured to include a resin material" means that, when the entire material constituting main body portion 70A is taken as 100% by mass, the content of the resin material is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. In other words, the material constituting main body portion 70A can contain materials other than the resin material in addition to the resin material.

[0044] 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 main body 70A may be molded using any molding method.

[0045] The resin material contained in the material constituting the coating 70 is preferably an olefin-based random copolymer, more preferably a resin containing a polyolefin skeleton as a main component, even more preferably a polyolefin as a main component, and even more preferably a polypropylene as a main component. The polyolefin may be an acid-modified polyolefin. The resin material contained in the material constituting the coating 70 preferably contains multiple types of amide-based lubricants. Furthermore, the resin material contained in the material constituting the coating 70 preferably contains multiple types of amide-based lubricants that further contain unsaturated fatty acid amides in addition to saturated fatty acid amides. The resin material contained in the material constituting the coating 70 may be a polyolefin resin to which a propylene-based elastomer having a melting point higher than 150°C has been added.

[0046] 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 / decane dicarboxylate). Among these, polybutylene terephthalate is preferred as the resin material from the viewpoint of improving heat resistance and pressure resistance.

[0047] 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, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (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.

[0048] 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 bonding portion 70B against temperature changes can be improved.

[0049] The melt mass flow rate of the resin material contained in the material constituting the main body 70A 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.

[0050] The main body 70A has a first surface 70X and a second surface 70Y. The first surface 70X faces the electrode assembly 20. An opening 70Z is formed over substantially the entire first surface 70X. The second surface 70Y is the surface opposite the first surface 70X. An opening 70YA into which the lid main body 80 is fitted is formed in the second surface 70Y. The opening 70YA penetrates the second surface 70Y. The shape of the opening 70YA in a front view can be selected arbitrarily depending on the shape of the lid main body 80. The shape of the opening 70YA may be a square, rectangle, a polygon with more sides than a triangle, a circle, or an ellipse. In this embodiment, the shape of the opening 70YA in a front view is rectangular. The corners of the opening 70YA are preferably rounded by performing a rounding process. When the main body 70A is made of a resin material, it is preferable that an adhesive film bondable to metal materials and resin materials be bonded to at least a portion of the inner circumferential surface of the opening 70YA, from the viewpoint of suitably joining the lid main body 80. In another example, when the main body 70A is made of a resin material, it is preferable that at least a portion of the portion of the main body 70A corresponding to the inner circumferential surface of the opening 70YA has a layer bondable to metal materials, from the viewpoint of suitably joining the lid main body 80.

[0051] The main body 70A has a lid seal portion 71 and a protruding portion 77. The lid seal portion 71 is heat-sealed to the heat-fusible resin layer 53 of the exterior film 50 via a joint portion 70B. The lid seal portion 71 includes a first seal surface 71A, a second seal surface 71B, a third seal surface 71C, and a fourth seal surface 71D. The first seal surface 71A forms the top surface of the lid body 60. The first seal surface 71A extends in a first direction (the LR direction in this embodiment) when viewed from the front of the lid body 60. The second seal surface 71B and the third seal surface 71C are connected to the first seal surface 71A and form the side surfaces of the lid body 60. The second seal surface 71B and the third seal surface 71C extend in a second direction (the UD direction in this embodiment) that intersects with the first direction when viewed from the front 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 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 sealing surface 71D forms the lower surface of the lid 60. The fourth sealing surface 71D extends in the first direction (the LR direction in this embodiment) in a front view of the lid 60.

[0052] The protrusion 77 protrudes inward from the lid seal portion 71 into the main body portion 70A. The protrusion 77 defines the portion that covers the lid main body 80, in other words, the opening 70YA. The amount by which the protrusion 77 protrudes from the lid seal portion 71 can be selected as desired. The greater the amount by which the protrusion 77 protrudes from the lid seal portion 71, the smaller the opening area of ​​the opening 70YA. In other words, the smaller the amount by which the protrusion 77 protrudes from the lid seal portion 71, the larger the opening area of ​​the opening 70YA. The protrusion 77 may be omitted from the main body portion 70A.

[0053] The lid seal portion 71 further includes boundaries 72, 73, 74, and 75. The boundary 72 is the boundary between the first seal surface 71A and the second seal surface 71B. The boundary 73 is the boundary between the first seal surface 71A and the third seal surface 71C. The boundary 74 is the boundary between the fourth seal surface 71D and the second seal surface 71B. The boundary 75 is the boundary between the fourth seal surface 71D and the third seal surface 71C. The shapes of the boundaries 72 to 75 may be angular, or may be rounded by applying a rounding process. In this embodiment, the boundaries 72 to 75 are angular.

[0054] When the lid body 60 is generally plate-shaped, it is preferable that the lid body 60 have a certain thickness so that deformation of the exterior body 40 is suppressed even when the power storage device 10 is placed on top of it. From another perspective, when the lid body 60 is plate-shaped, it is preferable that the lid seal portion 71 of the lid body 60 have a certain thickness so that the lid seal portion 71 of the lid body 60 and the exterior film 50 can be appropriately heat-sealed when forming the second sealing portion 92 described below. The minimum thickness of the lid seal portion 71 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 thickness of the lid seal portion 71 of the lid body 60 is, for example, 20 mm, more preferably 15 mm, and even more preferably 10 mm. The maximum thickness of the lid seal portion 71 of the lid body 60 may be 20 mm or more. Preferred ranges for the thickness of the lid seal portion 71 of the lid body 60 are 1.0 mm to 20 mm, 1.0 mm to 15 mm, 1.0 mm to 10 mm, 3.0 mm to 20 mm, 3.0 mm to 15 mm, 3.0 mm to 10 mm, 4.0 mm to 20 mm, 4.0 mm to 15 mm, and 4.0 mm to 10 mm. The thickness of the lid seal portion 71 of the lid body 60 may vary depending on the region of the lid body 60. When the thickness of the lid seal portion 71 of the lid body 60 varies depending on the region, the thickness of the lid seal portion 71 of the lid body 60 is the thickness of the thickest portion.

[0055] The lid body 80 shown in FIG. 5 is made up of a metal material. The definition of "made up of a metal material" and the specifications of the metal material making up the lid body 80 are the same as those for the covering body 70. The lid body 80 has a first surface 81, a second surface 82, and a covering portion 83. The first surface 81 faces the electrode body 20. The first surface 81 is joined to the end 31 of the current collector 30 of the electrode body 20 by, for example, welding. The second surface 82 is the surface opposite the first surface 81. An electrode terminal may be connected to the second surface 82.

[0056] When the lid body 80 is made of a metal material, it preferably has the corrosion-resistant coating described in connection with the barrier layer 52. To ensure favorable bonding between the lid body 80 and the main body 70A of the cover 70, the lid body 80 may include at least one of an adhesive film and an adhesive layer. The adhesive film or adhesive layer may be a single layer or a multilayer, and preferably contains at least a resin material having a polar group. The adhesive layer can be formed by dip coating, a dispenser, inkjet printing, spraying, screen printing, or the like.

[0057] The covering portion 83 is connected to the first surface 81 and the second surface 82, and at least a portion of the covering portion 83 is covered by the covering body 70. In this embodiment, the lid main body 80 is fitted into the opening 70YA of the covering body 70, so that the entire covering portion 83 is covered by the inner circumferential surface of the opening 70YA. When the lid main body 80 is fitted into the opening 70YA of the covering body 70, a portion of the covering portion 83 may be exposed from the covering body 70.

[0058] The covering portion 83 includes a first covering portion 83A, a second covering portion 83B, a third covering portion 83C, and a fourth covering portion 83D. The first covering portion 83A forms the upper surface of the lid main body 80. The first covering portion 83A extends in a first direction (in this embodiment, the LR direction) when viewed from the front of the lid main body 80. The second covering portion 83B and the third covering portion 83C are connected to the first covering portion 83A and form the side surfaces of the lid main body 80. The second covering portion 83B and the third covering portion 83C extend in a second direction (in this embodiment, the UD direction) that intersects with the first direction when viewed from the front of the lid main body 80. In this embodiment, the first direction and the second direction are orthogonal when viewed from the front of the lid main body 80. The first direction and the second direction do not have to be orthogonal when viewed from the front of the lid main body 80. The fourth covering portion 83D forms the lower surface of the lid main body 80. The fourth covering portion 83D extends in a first direction (LR direction in this embodiment) when the lid main body 80 is seen from the front.

[0059] The covering portion 83 further includes boundaries 84, 85, 86, and 87. The boundary 84 is the boundary between the first covering portion 83A and the second covering portion 83B. The boundary 85 is the boundary between the first covering portion 83A and the third covering portion 83C. The boundary 86 is the boundary between the fourth covering portion 83D and the second covering portion 83B. The boundary 87 is the boundary between the fourth covering portion 83D and the third covering portion 83C. The shapes of the boundaries 84 to 88 may be angular, or may be rounded by applying a rounding process. In this embodiment, the boundaries 84 to 87 are angular.

[0060] From the viewpoint of suitably heat-sealing the main body 70A and the heat-sealable resin layer 53 of the exterior film 50, the volume of the main body 70A is preferably smaller than the volume of the lid main body 80. If the volume of the main body 70A is smaller than the volume of the lid main body 80, heat is prevented from being absorbed by the main body 70A when the main body 70A and the heat-sealable resin layer 53 of the exterior film 50 are heat-sealed together via the joint 70B, and therefore the time required for heat-sealing can be shortened.

[0061] The joining portion 70B is arranged to suitably join the main body portion 70A and the heat-sealable resin layer 53 of the exterior film 50. The joining portion 70B may be, for example, a resin molded product made up of a resin material. In this embodiment, the joining portion 70B is a resin molded product. Here, the definition of "made up of a resin material" is the same as that explained for the main body portion 70A.

[0062] In another example, the bonding portion 70B may be an adhesive film that can be bonded to metal materials and resin materials. Any adhesive film can be selected as long as it can bond the heat-sealable resin layer 53 of the exterior film 50 to the main body portion 70A. 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 main body portion 70A. The material constituting the heat-sealable resin layer of the adhesive film on the side that is bonded to the main body portion 70A is preferably an acid-modified polyolefin resin graft-modified with an acid such as maleic anhydride. The acid-modified polyolefin is not particularly limited as long as it is an acid-modified polyolefin, but preferably includes a polyolefin graft-modified with an unsaturated carboxylic acid or its anhydride. Specific examples of acid-modified polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, polypropylene block copolymers (e.g., propylene-ethylene block copolymers), and polypropylene random copolymers (e.g., propylene-ethylene random copolymers); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred, with polypropylene being particularly preferred.

[0063] The acid-modified polyolefin may be a cyclic polyolefin. For example, a carboxylic acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a cyclic polyolefin by substituting an α,β-unsaturated carboxylic acid or an anhydride thereof for some of the monomers constituting the cyclic polyolefin, or by block polymerizing or graft polymerizing an α,β-unsaturated carboxylic acid or an anhydride thereof with a cyclic polyolefin.

[0064] The acid-modified cyclic polyolefin is a copolymer of an olefin and a cyclic monomer. Examples of the olefin constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Examples of the cyclic monomer constituting the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, cyclic alkenes are preferred, and norbornene is even more preferred. Another example of a constitutive monomer is styrene. Examples of carboxylic acids or anhydrides thereof used for acid modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride. The heat-sealable resin layer of the adhesive film on the side bonded to the exterior film 50 is preferably made of the same material as the heat-sealable resin layer 53 of the exterior film 50. The adhesive film preferably has adhesive properties. If the adhesive film has adhesiveness, one of the exterior film 50 and the main body 70A is less likely to shift position relative to the other when joining the exterior film 50 and the main body 70A. Adhesion can be imparted to the adhesive film by incorporating a tackifying resin into the heat-sealable resin layer of the adhesive film.

[0065] The heat-resistant substrate layer may be a heat-resistant film or nonwoven fabric. Materials constituting the heat-resistant substrate layer include, for example, polyolefin resins, polyamide resins, polyester resins, epoxy resins, acrylic resins, fluororesins, silicone resins, phenolic resins, polyetherimides, polyimides, polycarbonates, and mixtures or copolymers thereof. The heat-resistant substrate layer may have the same layer structure as the heat-fusible resin layer.

[0066] In yet another example, the bonding portion 70B may be an adhesive. When the bonding portion 70B is an adhesive film or layer, the bonding portion 70B may be a single layer or a multilayer, and preferably contains at least a resin material having a polar group. The adhesive layer can be formed by dip coating, a dispenser, inkjet printing, spraying, screen printing, or the like.

[0067] In this embodiment, the first sealed portion 91 is formed by heat-sealing the surfaces (heat-fusible resin layers 53) of the exterior film 50 that face each other.

[0068] The first sealed portion 91 includes a portion where the first edge 50A and the second edge 50B of the exterior film 50 shown in FIG. 3 are overlapped. The first sealed portion 91 extends in the longitudinal direction (FB direction) of the exterior body 40. The position where the first sealed portion 91 is formed in the exterior body 40 can be selected arbitrarily. In the present embodiment, the base 91X of the first sealed portion 91 is preferably located on the side 43 at the boundary between the first surface 41A and the second surface 42A of the exterior body 40. The base 91X of the first sealed portion 91 may be located on any surface of the exterior body 40. From the viewpoint of configuring the power storage device 10 compactly, it is preferable that the first sealed portion 91 is folded onto, for example, the first surface 41A or the second surface 42A of the exterior body 40 when the power storage device 10 is in use.

[0069] In this embodiment, the heat-sealable resin layer 53 of the exterior film 50 and the lid seal portion 71 of the main body 70A are heat-sealed via the joint portion 70B to form the second sealed portion 92. Hereinafter, the seal strength between the heat-sealable resin layer 53 of the exterior film 50 and the lid seal portion 71 of the lid body 60 may be referred to as the seal strength of the second sealed portion 92. The seal strength of the second sealed portion 92 is the seal strength between the heat-sealable resin layer 53 and the lid body 60 at the long side portion of the lid seal portion 71, i.e., the lid seal portion 71 extending in the L-R (width) direction in FIG. 1A .

[0070] The seal strength of the second sealing portion 92 is measured as follows. First, a slit is made in the portion of the exterior film 50 that constitutes the first surface 41A of the exterior body 40, forming three strip-shaped members 41X, 41Y, and 41Z aligned in the L-R direction (see the two-dot chain lines in FIG. 1B). The width of the three strip-shaped members 41X, 41Y, and 41Z in the L-R direction is 15 mm. The ends of the strip-shaped members 41X, 41Y, and 41Z are joined to the lid body 60 at the second sealing portion 92. The length of the lid body 60 in the L-R 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 strength of the strip-shaped members 41X, 41Y, and 41Z is the peak value of each seal strength. In this embodiment, the seal strength of the second sealing portion 92 is the average value of the seal strengths of the strip-shaped members 41X, 41Y, and 41Z. When the length of the lid body 60 in the L-R direction 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 length of the lid body 60 in the L-R direction 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 in a 15 mm width. The seal strength of the second sealing portion 92 is the average value of the seal strengths of the three strip-shaped members converted to a 15 mm width. Note that when the lid body 60 is divided into multiple parts including long and short sides, the seal strength of the second sealing portion 92 is the seal strength of the long sides of the lid seal portions 71 of the multiple parts.

[0071] From the viewpoint of suitably maintaining the state in which the electrode assembly 20 is sealed by the exterior housing 40, the seal strength of the second sealing portion 92 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 portion 92 is 40 N / 15 mm or more, the state in which the electrode assembly 20 is sealed by the exterior housing 40 is suitably maintained even after the electricity storage device 10 has been used for, for example, several years (less than 10 years). When the seal strength of the second sealing portion 92 is 85 N / 15 mm or more, the state in which the electrode assembly 20 is sealed by the exterior housing 40 is suitably maintained even after the electricity storage device 10 has been used for, for example, 10 years or more. The seal strength of the second sealing portion 92 is preferably 300 N / 15 mm or less. A preferred range for the seal strength of the second sealing portion 92 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.

[0072] <1-2. Method for manufacturing electricity storage devices> FIG. 8 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, and a fifth step. The first step to the fifth step are performed, for example, by a manufacturing apparatus for the electricity storage device 10. At least some of the first step to the fifth step may be performed by an operator. Note that the first step to the fifth step are names of the steps in the method for manufacturing the electricity storage device 10 specified for convenience, and do not necessarily indicate the order of the steps. The order of the following steps can be changed as desired.

[0073] In the first process (film bonding process) of step S1, the manufacturing equipment bonds main body portion 70A of cover 70 and heat-fusible resin layer 53 of exterior film 50 via bonding portion 70B by heat sealing or ultrasonic sealing. That is, the first process is a process of forming second sealing portion 92. Hereinafter, the element in which cover 70 and exterior film 50 are bonded together will be referred to as an intermediate.

[0074] The second step of step S2 is carried out before or after the first step. In the second step, the manufacturing device electrically connects the lid main body 80 and the electrode body 20.

[0075] The third step of step S3 is performed after the first and second steps. In the third step, the manufacturing apparatus inserts the electrode assembly 20, with the lid body 80 connected, into the interior of the intermediate body through the opening 70YA of the main body 70A of the intermediate body. Upon completion of the third step, the electrode assembly 20 is housed inside the intermediate body. The opening 70YA of the main body 70A is closed by the lid body 80.

[0076] The fourth process (closing process) of step S4 is performed after the third process. In the fourth process, the manufacturing apparatus joins the main body 70A and the lid main body 80 together, for example, by welding. The main body 70A and the lid main body 80 may be joined together by caulking, press fitting, shrink fitting, caulking welding, pressure welding, brazing, or an adhesive. When the main body 70A and the lid main body 80 are fixed together by caulking, it is preferable that an adhesion assisting member be disposed between the main body 70A and the lid main body 80. The adhesion assisting member is, for example, a foam material, a sponge, a resin, or a rubber.

[0077] The fifth step of step S5 is performed after the fourth step. In the fifth step, the manufacturing apparatus forms a first sealed portion 91 by heat-sealing the heat-sealable resin layer 53 in a portion including the first edge 50A of the exterior film 50 and the heat-sealable resin layer 53 in a portion including the second edge 50B.

[0078] 9 is a flowchart showing another example of a method for manufacturing the electricity storage device 10. 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 designated for convenience as names of the steps in the method for manufacturing the electricity storage device 10, and do not necessarily indicate the order of the steps. The order of the following steps can be changed as desired.

[0079] In the eleventh process of step S11, the manufacturing apparatus places a pair of covering bodies 70 on the sides of the electrode body 20.

[0080] The twelfth step of step S12 is performed after the eleventh step. In the second step, the manufacturing apparatus winds the exterior film 50 around the electrode assembly 20 and the covering body 70 while tension is applied to the exterior film 50, while restricting the movement of the electrode assembly 20 and the covering body 70 with a restricting means. The restricting means is, for example, a groove into which the electrode assembly 20 and the covering body 70 are fitted. The restricting means may be a device that applies an external force to the electrode assembly 20 and the covering body 70 to prevent the electrode assembly 20 and the covering body 70 from moving. The restricting means may be a device that applies a force to the electrode assembly 20 and the covering body 70 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.

[0081] The thirteenth step (film bonding step) of step S13 is performed after the twelfth step. In the thirteenth step, the manufacturing apparatus bonds the main body portion 70A of the cover 70 and the heat-fusible resin layer 53 of the exterior film 50 via the bonding portion 70B by heat sealing or ultrasonic sealing. That is, the thirteenth step is a step of forming the second sealing portion 92.

[0082] The 14th step of step S14 is performed after the 13th step. In the 14th step, the manufacturing apparatus electrically connects the electrode body 20 and the lid body 80. The 14th step can be performed outside the cover body 70. Therefore, the 14th step can be easily performed.

[0083] The 15th step (closing step) of step S15 is performed after the 14th step. In the 15th step, the manufacturing apparatus fits the lid main body 80 into the opening 70YA of the main body portion 70A, and joins the main body portion 70A and the lid main body 80 together by, for example, welding.

[0084] The 16th step of step S16 is performed after the 15th step. In the 16th step, the manufacturing apparatus forms a first sealed portion 91 by heat-sealing the heat-sealable resin layer 53 in a portion including the first edge 50A of the exterior film 50 and the heat-sealable resin layer 53 in a portion including the second edge 50B.

[0085] <1-3. Actions and Effects of Electricity Storage Devices> According to the electricity storage device 10, the lid body 60 includes the cover 70 and the lid main body 80, and therefore the electrode body 20 can be sealed by fitting the lid main body 80 into the opening 70YA of the cover 70. The electricity storage device 10 can be manufactured using a variety of procedures, as the electrode body 20 can be sealed at any timing during the manufacturing process.

[0086] [2. Modifications] The above-described embodiments are examples of possible forms of the electricity storage device, lid, covering, 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, covering, 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, 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.

[0087] <2-1. First modified example> In the above embodiment, the cover 70 does not necessarily have to have the bonding portion 70B. In the first modification, from the viewpoint of suitably bonding the main body 70A and the exterior film 50, it is preferable that the lid seal portion 71 of the main body 70A be subjected to a surface roughening treatment. Specific methods for the surface roughening treatment include, for example, shot blasting, polishing, anodizing, wet etching, plasma treatment, laser treatment, or surface roughening plating.

[0088] In the first modification, from the viewpoint of suitably joining the main body 70A and the lid main body 80, at least a portion of the surface of the lid seal portion 71, i.e., at least a portion of the first seal surface 71A, the second seal surface 71B, the third seal surface 71C, and the fourth seal surface 71D, may be provided with a corrosion-resistant coating. Here, the corrosion-resistant coating refers to a thin film that is formed on the surface of the lid seal portion 71 by, for example, hydrothermal conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or corrosion prevention treatment such as applying a coating agent, to provide the lid seal portion 71 with corrosion resistance (e.g., acid resistance, alkali resistance, etc.). Specifically, the corrosion-resistant coating refers to a coating that improves the acid resistance of the lid seal portion 71 (acid-resistant coating), a coating that improves the alkali resistance of the lid seal portion 71 (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 of treatments. Furthermore, it can be made of not just one layer but multiple layers. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the surface of the metal foil 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 lid seal portion 71 is provided with a corrosion-resistant coating, the corrosion-resistant coating is also included in the lid seal portion 71.

[0089] <2-2. Second modified example> In the above embodiment, the covering body 70 may be arranged so that the second surface 70Y of the main body portion 70A faces the electrode body 20. In the second modified example, in the first step shown in Fig. 8 or the thirteenth step shown in Fig. 9, a receiver for the heat seal bar can be placed in the space 79, so that the first step or the thirteenth step can be preferably carried out.

[0090] <2-3.Third modified example> In the above embodiment, the covering body 70 may cover at least a part of the first surface 81 and the second surface 82 of the lid body 80 instead of or in addition to the covering portion 83 of the lid body 80 .

[0091] <2-4. Fourth Modification> In the above embodiment, the exterior film 50 of the electricity 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 inward so that the outer surfaces of the exterior films 50 come into contact with each other, as in a Goebel-top container, or may be folded toward any surface of the exterior body 40, as in a brick container.

[0092] <2-5. Fifth Modification> In the above embodiment, the exterior body 40 may not have one of the two lid bodies 60. In this modification, in the FB direction, in the portion of the exterior body 40 where the lid body 60 is omitted, the electrode body 20 is sealed by closing the portion of the exterior film 50 that protrudes outward beyond the electrode body 20. As in the seventh 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.

[0093] <2-6. Sixth Variation> 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.

[0094] <2-7. Seventh 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]

[0095] 10: Energy storage device 20: Electrode body 40: Exterior body 50: Exterior film 60: Lid 70: Covering body 70A: Main body 70B: Joint 71: Lid seal 77:Protrusion 80: Lid body

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 that seals the electrode body together with the exterior film, The lid body is A lid body including a metal material; a covering body that is joined to the exterior film and covers at least a portion of the lid body; Energy storage device.

2. The covering body has a main body portion that includes a metal material. The electricity storage device according to claim 1 .

3. The volume of the main body is smaller than the volume of the lid main body. The electricity storage device according to claim 2 .

4. The coating body is a lid seal portion joined to the exterior film; a protrusion protruding from the lid seal portion and defining a portion covering an edge of the lid body; The electricity storage device according to any one of claims 1 to 3.

5. The covering further includes a joining portion that covers at least a portion of the edge of the main body portion. The electricity storage device according to claim 2 or 3.

6. The joint is a resin molded part. The electricity storage device according to claim 5 .

7. The bonding portion is an adhesive film that can be bonded to metal materials and resin materials. The electricity storage device according to claim 5 .

8. The joint is an adhesive. The electricity storage device according to claim 5 .

9. A lid body used as an exterior body of an electricity storage device, A lid body including a metal material; a covering body that is joined to the exterior film that constitutes the exterior body and covers at least a part of the edge of the lid body; Lid body.

10. A covering body constituting a lid body used as an exterior body of an electricity storage device, The lid body has a lid main body made of a metal material, The covering body is joined to the exterior film that constitutes the exterior body, and is configured to cover at least a part of the edge of the lid body. Covering body.

11. 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 that seals the electrode body together with the exterior film, The lid body is A lid body including a metal material; a covering body joined to the exterior film and covering at least a portion of the lid body, The method for manufacturing the electricity storage device includes: a film joining step of joining the exterior film and the covering body; a closing step of joining the cover and the lid body, which is performed after the film joining step. A method for manufacturing an electricity storage device.

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