Energy storage device, cover, covering, method for manufacturing an energy storage device

Abstract

This power storage device comprises an electrode body and an exterior body that seals the electrode body. The exterior body has: an exterior film in which the electrode body is wrapped; and a lid body that seals the electrode body together with the exterior film. The lid body has: a lid main body that is configured to contain a metal material; and a covering body that is joined to the exterior film, the covering body covering at least a portion of the edge of the lid main body.

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device, a lid body, a covering body, and a method for manufacturing an electricity storage device. [Background Art]

[0002] Patent Document 1 discloses an example of an electricity storage device. This electricity storage device includes an electrode body and an exterior body that seals the electrode body. The exterior body includes an exterior film wrapping the electrode body, and a lid body joined to the exterior film. [Prior Art Literature] [Patent Literature]

[0003] [Patent Literature 1] Japanese Unexamined Patent Publication No. 2022-123686 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] In the above electricity storage device, after the electrode body and the lid body are connected, the electrode body and the lid body are wrapped by the exterior film. In the above electricity storage device, the electrode body is sealed at the stage where the electrode body and the lid body are wrapped by the exterior film, so the procedure of steps in the manufacturing method is limited.

[0005] An object of the present invention is to provide an electricity storage device that can be manufactured through various procedures, a lid body used for the electricity storage device, a covering body that constitutes the lid body, and a method for manufacturing the electricity storage device. [Means for Solving the Problem]

[0006] A first aspect of the present invention relates to an energy storage device comprising an electrode body and an outer casing for sealing the electrode body, wherein the outer casing comprises an outer film that encloses the electrode body and a lid that seals the electrode body together with the outer film, and the lid comprises a lid body made of a metal material and a covering that is joined to the outer film and covers at least a part of the lid body.

[0007] A second aspect of the present invention relates to a power storage device according to the first aspect, wherein the covering has a main body made of a metal material.

[0008] A third aspect of the present invention relates to a power storage device according to the second aspect, wherein the volume of the main body is smaller than the volume of the lid body.

[0009] A fourth aspect of the present invention relates to a power storage device relating to any one of the first to third aspects, wherein the covering has a lid sealing portion that is joined to the outer film, and a protruding portion that protrudes from the lid sealing portion and defines a portion that covers the edge of the lid body.

[0010] A fifth aspect of the present invention relates to a power storage device according to the second or third aspect, wherein the covering further has a joint that covers at least a portion of the edge of the main body.

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

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

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

[0014] A lid according to the ninth aspect of the present invention is a lid used as an exterior body for an energy storage device, comprising a lid body made of 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 that constitutes a lid used as an outer casing for an energy storage device, wherein the lid has a lid body made of a metal material, and the covering is joined to an outer film constituting the outer casing and is configured to cover at least a portion of the edge of the lid body.

[0016] A method for manufacturing an energy storage device according to an eleventh aspect of the present invention comprises an electrode body and an outer casing for sealing the electrode body, wherein the outer casing has an outer film that wraps the electrode body and a lid that seals the electrode body together with the outer film, and the lid has a lid body made of a metal material and a covering that is joined to the outer film and covers at least a part of the lid body. The method for manufacturing the energy storage device includes a film joining step of joining the outer film and the covering, and a closing step performed after the film joining step of joining the covering and the lid body. [Effects of the Invention]

[0017] According to the energy storage device, cover, covering, and method for manufacturing the energy storage device of the present invention, the energy storage device can be manufactured using a variety of procedures. [Brief explanation of the drawing]

[0018] [Figure 1A] A perspective view of the energy storage device according to the embodiment. [Figure 1B] Figure 1A shows a diagram illustrating the method for measuring the seal strength of the second sealing portion of the energy storage device. [Figure 2] A cross-sectional view showing an example of the layer structure of the outer film of the energy storage device shown in Figure 1A. [Figure 3]A view of an expanded exterior film included in the electricity storage device of FIG. 1A. [Figure 4A] A perspective view of a main body portion of a covering body included in the electricity storage device of FIG. 1A. [Figure 4B] A cross-sectional view taken along line D4B-D4B in FIG. 4A. [Figure 5] A perspective view of a lid main body of a lid body included in the electricity storage device of FIG. 1A. [Figure 6] A front view of the electricity storage device of FIG. 1A. [Figure 7] A cross-sectional view taken along line D7-D7 in FIG. 1A. [Figure 8] A flowchart showing an example of a method for manufacturing the electricity storage device of FIG. 1A. [Figure 9] A flowchart showing another example of a method for manufacturing the electricity storage device of FIG. 1A. DETAILED DESCRIPTION OF EMBODIMENTS

[0019] Hereinafter, an electricity storage device according to an embodiment of the present invention will be described with reference to the drawings. In the present specification, a numerical range indicated by "~" means "not less than" and "not more than". For example, the notation "2 to 15 mm" means not less than 2 mm and not more than 15 mm.

[0020] [1. Embodiment] <1-1. Configuration of Electricity Storage Device> Figure 1A is a schematic perspective view of the energy storage device 10 of the embodiment. Figure 1B is a diagram showing a method for measuring the seal strength of the second sealing portion 92 of the energy storage device 10 of Figure 1. Figure 2 is a cross-sectional view showing an example of the layer configuration of the outer film 50 provided on the energy storage device 10 of Figure 1A. Figure 3 is a view of the outer film 50 provided on the energy storage device 10 of Figure 1A in an unfolded state. Figure 4A is a perspective view of the main body portion 70A of the covering 70 provided on the energy storage device of Figure 1A. Figure 4B is a cross-sectional view along the line D4B-D4B in Figure 4A. Figure 5 is a perspective view of the lid body 80 provided on the energy storage device 10 of Figure 1A. Figure 6 is a front view of the energy storage device 10 of Figure 1A. Figure 7 is a cross-sectional view along the line D7-D7 in Figure 1. In Figure 1A, the arrow UD indicates the thickness direction of the energy storage device 10, the arrow LR indicates the width direction of the energy storage device 10, and the arrow FB indicates the depth direction of the energy storage device 10. The directions indicated by arrows UDLRFB are the same in all subsequent figures.

[0021] The energy storage device 10 comprises an electrode body 20 including a current collector 30 and an outer casing 40. The electrode body 20 includes electrodes (positive and negative electrodes) that constitute an energy storage component such as a lithium-ion battery, capacitor, all-solid-state battery, semi-solid-state battery, pseudo-solid-state 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 shape of the electrode body 20 is substantially rectangular parallelepiped. Note that "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 part of its outer surface, for example. The shape of the electrode body 20 may be, for example, a cylinder or a polygonal prism.

[0022] The outer casing 40 seals the electrode body 20. The outer casing 40 comprises an outer film 50 and a lid 60. The outer film 50 wraps around the electrode body 20 so that a pair of openings 40A are formed. In this embodiment, the outer film 50 is wrapped around the electrode body 20 so that a pair of openings 40A are formed. Alternatively, the electrode body 20 may be housed inside the outer film 50, which is configured in a cylindrical shape so that a pair of openings 40A are formed, and the openings 40A may be closed by the lid 60. The outer casing 40 has a pair of first surfaces 41A, 41B and a pair of second surfaces 42A, 42B. In this embodiment, the pair of first surfaces 41A, 41B are substantially the same size. In this embodiment, the pair of second surfaces 42A, 42B are substantially the same size. The area of ​​the pair of first surfaces 41A, 41B is larger than that of the pair of second surfaces 42A, 42B. The pair of covers 60 are positioned to the sides of the electrode body 20 so as to close the pair of openings 40A.

[0023] For example, one method involves forming a recess in the outer film 50 to accommodate the electrode body 20 through cold forming. However, forming a deep recess by such a method is not always easy. If one attempts to form a deep recess (for example, a forming depth of 15 mm) by cold forming, pinholes or cracks may occur in the outer film 50, which is likely to lead to a decrease in battery performance. On the other hand, the outer body 40 seals the electrode body 20 by wrapping the outer film 50 around the electrode body 20, so the electrode body 20 can be easily sealed regardless of its thickness. Furthermore, in order to reduce the dead space between the electrode body 20 and the outer film 50 in order to improve the volumetric energy density of the energy storage device 10, it is preferable that the outer film 50 is wrapped so as to be in contact with the outer surface of the electrode body 20. In addition, in all-solid-state batteries, it is necessary to eliminate the space between the electrode body 20 and the outer film 50 from the viewpoint that high pressure must be applied uniformly from the outside of the battery in order to achieve battery performance, so it is preferable that the outer film 50 is wrapped so as to be in contact with the outer surface of the electrode body 20.

[0024] As shown in Figure 2, the outer film 50 is a laminate (laminate film) having, for example, a base layer 51, a barrier layer 52, and a heat-sealable resin layer 53 in that order. Note that the outer film 50 does not necessarily need to include all of these layers; for example, the barrier layer 52 may be omitted. That is, the outer film 50 only needs to be made of a flexible and easily bendable material, such as a resin film. It is preferable that the outer film 50 is heat-sealable. The innermost and outermost layers of the outer film 50 may be the heat-sealable resin layer 53. In this case, the outer film 50 may enclose the electrode body 20 and the lid 60 by joining the outermost and innermost layers.

[0025] The overall thickness of the outer film 50 can be arbitrarily selected. From the viewpoint of strength, the thickness of the outer film 50 is preferably 50 μm or more. From the viewpoint of moldability or conformability, the thickness of the outer film 50 is preferably 1200 μm or less. The thickness of the outer film 50 is preferably within the range of 50 μm to 1200 μm.

[0026] The base layer 51 included in the outer film 50 is a layer that imparts heat resistance to the outer film 50 and suppresses the occurrence of pinholes that may occur during processing or distribution. The base layer 51 is composed of, for example, at least one stretched polyester resin layer and a stretched polyamide resin layer. For example, by including at least one stretched polyester resin layer and a stretched polyamide resin layer in the base layer 51, the barrier layer 52 can be protected during processing of the outer film 50, and the breakage of the outer film 50 can be suppressed. Furthermore, from the viewpoint of increasing the tensile elongation of the outer film 50, the stretched polyester resin layer is preferably a biaxially oriented polyester resin layer, and the stretched polyamide resin layer is preferably a biaxially oriented polyamide resin layer. Moreover, from the viewpoint of excellent puncture strength or impact strength, the stretched polyester resin layer is more preferably a biaxially oriented polyethylene terephthalate (PET) film, and the stretched polyamide resin layer is more preferably a biaxially oriented nylon (ONy) film. The base 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 at least prevents the penetration of moisture. The barrier layer 52 is joined to the substrate layer 51, for example, via an adhesive layer 54. Examples of barrier layers 52 include metal foil, vapor-deposited film, and resin layer. Examples of vapor-deposited films include metal vapor-deposited films, inorganic oxide vapor-deposited films, and carbon-containing inorganic oxide vapor-deposited films. Examples of resin layers include fluorine-containing resins such as polymers mainly composed of polyvinylidene chloride, chlorotrifluoroethylene (CTFE), polymers mainly composed of tetrafluoroethylene (TFE), polymers having fluoroalkyl groups, and polymers mainly composed of fluoroalkyl units, as well as ethylene vinyl alcohol copolymers. In addition, a resin film having at least one of these vapor-deposited films and resin layers can also be provided as the barrier layer 52. Multiple layers of the barrier layer 52 may be provided. Preferably, the barrier layer 52 includes a layer made of a metal material. Examples of metal materials constituting the barrier layer 52 include aluminum alloys, stainless steel, titanium steel, and steel sheets. When used as a metal foil, it is preferable to include at least one of aluminum alloy foil and stainless steel foil.

[0028] In the barrier layer 52, the layer composed of the aforementioned metal material may include recycled metal material. Examples of recycled metal material include recycled aluminum alloy, stainless steel, titanium steel, or steel sheet. These recycled materials can each be obtained by known methods. Recycled aluminum alloy can be obtained, for example, by the manufacturing method described in International Publication No. 2022 / 092231. The barrier layer 52 may be composed solely of recycled material, or it may be composed of a mixture of recycled material and virgin material. Recycled metal material refers to metal material that has been recovered, isolated, and purified from various products used in the market or waste generated from manufacturing processes to make it reusable. Virgin metal material refers to new metal material refined from natural metal resources (raw materials) and is not recycled material.

[0029] From the viewpoint of improving the formability or conformability of the outer film 50, the aluminum alloy foil is more preferably a soft aluminum alloy foil composed of, for example, an annealed aluminum alloy, and from the viewpoint of further improving formability or conformability, it is more preferably an aluminum alloy foil containing iron. In an iron-containing aluminum alloy foil (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, and more preferably 0.5 to 2.0% by mass. By having an iron content of 0.1% by mass or more, an outer film 50 with better formability can be obtained. By having an iron content of 9.0% by mass or less, an outer film 50 with better flexibility can be obtained. Silicon, magnesium, copper, manganese, etc. may also be added as needed. Softening can be achieved by annealing treatment, etc. From the viewpoint of improving the mechanical strength of the outer film 50, the aluminum alloy foil is more preferably a hard aluminum alloy foil composed of, for example, a work-hardened aluminum alloy. Examples of hard aluminum alloy foils include aluminum alloy foils having compositions 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 outer film 50, it is preferable that the aluminum alloy foil is an aluminum alloy foil containing magnesium. In an 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 those having compositions specified in JIS H4000:2017 A5005P-O, JIS H4000:2017 A5050P-O, and JIS H4000:2017 A5052P-O.

[0030] Furthermore, examples of stainless steel foils include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation-hardening stainless steel foils. Moreover, from the viewpoint of providing an outer film 50 with excellent formability, it is preferable that the stainless steel foil be made of austenitic stainless steel.

[0031] Specific examples of austenitic stainless steels that make up stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred among these.

[0032] In the case of metal foil, the thickness of the barrier layer 52 should at least function as a barrier layer that prevents moisture from penetrating, 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. Also, the thickness of the barrier layer 52 is preferably about 9.0 μm or more, even more preferably about 20 μm or more, and more preferably about 25 μm or more. Furthermore, preferred ranges for the thickness of the barrier layer 52 include approximately 9.0 to 1000 μm, 9.0 to 1000 μm, 9.0 to 1000 μm, 9.0 to 85 μm, 9.0 to 50 μm, 9.0 to 40 μm, 9.0 to 35 μm, 20 to 85 μm, 20 to 50 μm, 20 to 40 μm, 20 to 35 μm, 25 to 85 μm, 25 to 50 μm, 25 to 40 μm, and 25 to 35 μm. When the barrier layer 52 is made of aluminum alloy foil, the above ranges are particularly preferred. Furthermore, from the viewpoint of providing the outer film 50 with high moldability and high rigidity, 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, even more preferably about 55 μm or more, and also preferably about 200 μm or less, more preferably about 85 μm or less, even more preferably about 75 μm or less, even more preferably about 70 μm or less, and preferably The suitable ranges are approximately 35-200 μm, 35-85 μm, 35-75 μm, 35-70 μm, 45-200 μm, 45-85 μm, 45-75 μm, 45-70 μm, 50-200 μm, 50-85 μm, 50-75 μm, 50-70 μm, 55-200 μm, 55-85 μm, 55-75 μm, and 55-70 μm. The high moldability of the outer film 50 facilitates deep drawing, which can contribute to increasing the capacity of the energy storage device. Furthermore, while increasing the capacity of the energy storage device increases its weight, the increased rigidity of the outer film 50 contributes to the high sealing performance of the energy storage device.Furthermore, in particular when the barrier layer 52 is composed 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 especially preferably about 25 μm or less. Also, the thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. Furthermore, 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, if the barrier layer 52 is aluminum foil, it is preferable to provide a corrosion-resistant coating on at least the side opposite to the base layer 51 to prevent dissolution and corrosion. The barrier layer 52 may have a corrosion-resistant coating on both sides. Here, a corrosion-resistant coating refers to a thin film that provides corrosion resistance (e.g., acid resistance, alkali resistance, etc.) to the barrier layer 52 by performing corrosion prevention treatments on the surface of the barrier layer 52, such as hot water modification treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or coating agent application. Specifically, a corrosion-resistant coating means 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), etc. One type of treatment may be performed to form the corrosion-resistant coating, or two or more types may be combined. In addition, it is possible to have multiple layers instead of just one layer. Furthermore, among these treatments, hydrothermal modification and anodic oxidation are processes that dissolve the surface of the metal foil with a treatment agent to form a metal compound with excellent corrosion resistance. These treatments may also be included in the definition of chemical conversion treatment. Additionally, if the barrier layer 52 has a corrosion-resistant coating, the barrier layer 52 includes the corrosion-resistant coating.

[0034] The corrosion-resistant coating prevents delamination between the barrier layer 52 (e.g., aluminum alloy foil) and the base layer 51 during the molding of the outer film 50, prevents dissolution and corrosion of the surface of the barrier layer 52 due to hydrogen fluoride generated by the reaction of electrolyte and water, and in particular prevents the dissolution and corrosion of aluminum oxide present on the surface of the barrier layer 52 when the barrier layer 52 is aluminum alloy foil, and 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 during molding.

[0035] The heat-sealable resin layer 53 is joined to the barrier layer 52, for example, via an adhesive layer 55. The heat-sealable resin layer 53 included in the outer film 50 is a layer that imparts heat-seal sealing properties to the outer film 50. Examples of the heat-sealable resin layer 53 include polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, polyolefin resins such as polyethylene resin and polypropylene resin, or acid-modified polyolefin resins obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The thickness of the heat-sealable resin layer 53 is preferably, for example, 20 to 300 μm, and more preferably 40 to 150 μm, from the viewpoint of sealing properties and strength.

[0036] The outer film 50 preferably has one or more layers having a buffering function (hereinafter referred to as "buffering layers") outside the heat-sealable resin layer 53, and more preferably outside the barrier layer 52. The buffering layers may be laminated on the outside of the base layer 51, or the base layer 51 may also have the function of a buffering layer. If the outer film 50 has multiple buffering layers, the multiple buffering layers may be adjacent to each other, or they may be laminated via the base layer 51 or the barrier layer 52, etc.

[0037] The materials constituting the buffer layer can be arbitrarily selected from materials having cushioning properties. Examples of cushioning materials include rubber, nonwoven fabric, or foamed sheet. Examples of rubber include natural rubber, fluororubber, or silicone rubber. The rubber hardness is preferably around 20 to 90. The materials constituting the nonwoven fabric are preferably materials with excellent heat resistance. When the buffer layer is made of nonwoven fabric, the lower limit of the buffer layer thickness is preferably 100 μm, more preferably 200 μm, and still more preferably 1000 μm. When the buffer layer is made of nonwoven fabric, the upper limit of the buffer layer thickness is preferably 5000 μm, and still more preferably 3000 μm. The preferred thickness ranges for the buffer layer are 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. Among these, the most preferred thickness range for the buffer layer is 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 still 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] If the outer film 50 has a buffer layer, the buffer layer functions as a cushion, thus preventing damage to the outer film 50 from impact when the energy storage device 10 is dropped or from handling during the manufacturing of the energy storage device 10.

[0040] The lid 60 comprises a covering 70 and a lid body 80.

[0041] The covering 70 has a main body portion 70A and a joint portion 70B. The main body portion 70A has a shape similar to, for example, a hollow rectangular parallelepiped. A space 79 is formed inside the main body portion 70A. The material constituting the main body portion 70A can be arbitrarily selected. From the viewpoint of easily joining with the lid body 80, it is preferable that the main body portion 70A is made up of a metallic material. Here, "made up of a metallic material" means that when the total material constituting the main body portion 70A is considered to be 100% by mass, the metallic 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. That is, the material constituting the main body portion 70A may contain materials other than metallic materials in addition to metallic materials. The metallic material constituting the main body portion 70A can be arbitrarily selected. The metallic material constituting the main body portion 70A is, for example, aluminum, aluminum alloy, nickel, copper, or copper alloy. For example, if 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 with nickel plating. The material constituting the main body 70A may also include recycled metal materials. In this embodiment, the main body 70A is made only of metal material. Since the main body 70A is made of metal material, it also functions as an electrode terminal. This simplifies the configuration of the energy storage device 10.

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

[0043] In another example, the main body 70A may be made up of a resin material. Here, "made up of a resin material" means that when the total mass of the materials constituting the main body 70A is considered to be 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 materials constituting the main body 70A may contain materials other than resin materials in addition to resin materials.

[0044] Specific examples of resins include thermoplastic resins such as polyester, polyolefin, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicon resin, and phenolic resin, as well as modified versions of these resins. The resin material may also be a mixture of these resins, a copolymer, or a modified version of a 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 by any molding method.

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

[0046] Examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyesters. Examples of copolymerized polyesters include copolymerized polyesters with ethylene terephthalate as the main repeating unit. Specifically, examples include copolymerized polyesters polymerized with ethylene isophthalate using ethylene terephthalate as the main repeating unit (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 improving heat resistance and pressure resistance.

[0047] Furthermore, specific examples of polyolefins include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylene such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymer of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymer of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. When polyolefin resins are copolymers, they may be block copolymers or random copolymers. Among these, polypropylene is preferred as the resin material because it has excellent heat-sealability and electrolyte resistance.

[0048] The resin material may contain fillers as needed. Specific examples of fillers include glass beads, graphite, glass fibers, and carbon fibers. By including the above-mentioned fillers in the resin material, the deformation resistance of the joint 70B to 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 according to JIS K7210-1:2014. The measurement temperature for the melt mass flow rate is 230°C.

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

[0051] The main body portion 70A has a lid sealing portion 71 and a protruding portion 77. The lid sealing portion 71 is heat-sealed to the heat-fusible resin layer 53 of the outer film 50 via a joint portion 70B. The lid sealing portion 71 includes a first sealing surface 71A, a second sealing surface 71B, a third sealing surface 71C, and a fourth sealing surface 71D. The first sealing surface 71A constitutes the upper surface of the lid 60. In a front view of the lid 60, the first sealing surface 71A extends in a first direction (in this embodiment, the LR direction). The second sealing surface 71B and the third sealing surface 71C connect to the first sealing surface 71A and constitute the side surface of the lid 60. In a front view of the lid 60, the second sealing surface 71B and the third sealing surface 71C extend in a second direction (in this embodiment, the UD direction) that intersects the first direction. In this embodiment, the first direction and the second direction are orthogonal in a front view of the lid 60. The first direction and the second direction do not have to be orthogonal in a front view of the lid 60. The fourth sealing surface 71D constitutes the lower surface of the lid 60. The fourth sealing surface 71D extends in the first direction (the L-R direction in this embodiment) in a front view of the lid 60.

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

[0053] The lid seal portion 71 further includes boundaries 72, 73, 74, and 75. Boundary 72 is the boundary between the first seal surface 71A and the second seal surface 71B. Boundary 73 is the boundary between the first seal surface 71A and the third seal surface 71C. Boundary 74 is the boundary between the fourth seal surface 71D and the second seal surface 71B. Boundary 75 is the boundary between the fourth seal surface 71D and the third seal surface 71C. The shape of boundaries 72 to 75 may be angular, or it may be rounded by R-processing. In this embodiment, boundaries 72 to 75 are angular.

[0054] If the lid 60 is plate-shaped as a whole, it is preferable that the lid 60 has a certain thickness so as to suppress deformation of the outer casing 40 even when the energy storage devices 10 are stacked on top of each other. From another viewpoint, if the lid 60 is plate-shaped, it is preferable that the lid seal portion 71 of the lid 60 has a certain thickness so as to allow for suitable heat sealing of the lid seal portion 71 of the lid 60 and the outer casing film 50 when forming the second sealing portion 92 described later. The minimum thickness of the lid seal portion 71 of the lid 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 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 60 may be 20 mm or more. The preferred range for the thickness of the lid seal portion 71 of the lid 60 is 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 60 may vary depending on the part of the lid 60. If the thickness of the lid seal portion 71 of the lid 60 varies depending on the part, the thickness of the lid seal portion 71 of the lid 60 is the thickness of the thickest part.

[0055] The lid body 80 shown in Figure 5 is constructed including a metal material. The definition of "constructed including a metal material" and the specifications of the metal material constituting the lid body 80 are the same as those for the covering 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, for example, by welding. The second surface 82 is the surface opposite to the first surface 81. Electrode terminals may be connected to the second surface 82.

[0056] If the lid body 80 is made of a metal material, it is preferable that the lid body 80 has a corrosion-resistant coating as described in the barrier layer 52. From the viewpoint of suitably joining the lid body 80 and the main body portion 70A of the covering 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 polar groups. The adhesive layer can be formed by dip coating, dispensing, inkjet, spraying, or screen printing.

[0057] The covering portion 83 is connected to the first surface 81 and the second surface 82, and at least a portion of it is covered by the covering body 70. In this embodiment, the entire covering portion 83 is covered by the inner circumferential surface of the opening 70YA when the lid body 80 is fitted into the opening 70YA of the covering body 70. When the lid 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 constitutes the upper surface of the lid body 80. In a front view of the lid body 80, the first covering portion 83A extends in a first direction (in this embodiment, the LR direction). The second covering portion 83B and the third covering portion 83C are connected to the first covering portion 83A and constitute the side surface of the lid body 80. In a front view of the lid 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 the first direction. In this embodiment, in a front view of the lid body 80, the first direction and the second direction are orthogonal. The first direction and the second direction do not have to be orthogonal in a front view of the lid body 80. The fourth covering portion 83D constitutes the lower surface of the lid body 80. The fourth covering portion 83D extends in the first direction (in this embodiment, the LR direction) when viewed from the front of the lid body 80.

[0059] The covering portion 83 further includes boundaries 84, 85, 86, and 87. Boundary 84 is the boundary between the first covering portion 83A and the second covering portion 83B. Boundary 85 is the boundary between the first covering portion 83A and the third covering portion 83C. Boundary 86 is the boundary between the fourth covering portion 83D and the second covering portion 83B. Boundary 87 is the boundary between the fourth covering portion 83D and the third covering portion 83C. The shape of boundaries 84 to 88 may be angular, or it may be rounded by R processing. In this embodiment, 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 outer film 50, it is preferable that the volume of the main body 70A is smaller than the volume of the lid body 80. When the volume of the main body 70A is smaller than the volume of the lid body 80, heat is suppressed from being drawn away by the main body 70A when heat-sealing the main body 70A and the heat-sealable resin layer 53 of the outer film 50 via the joint 70B, thus shortening the time required for heat sealing.

[0061] The joint portion 70B is positioned to suitably join the main body portion 70A and the heat-fusible resin layer 53 of the outer film 50. The joint portion 70B may be, for example, a resin molded product made of a resin material. In this embodiment, the joint portion 70B is a resin molded product. Here, the definition of "made of a resin material" is the same as the definition described for the main body portion 70A.

[0062] In another example, the joint 70B may be an adhesive film that can be bonded to metal and resin materials. The adhesive film can be arbitrarily selected as long as it is a film that can bond the heat-fusible resin layer 53 of the outer film 50 to the main body 70A. Preferably, the adhesive film is a laminated film having at least a heat-fusible resin layer, a heat-resistant substrate layer, and a heat-fusible resin layer in this order. The specifications for the heat-fusible resin layer of the adhesive film can be the same as those for the heat-fusible resin layer 53. The materials constituting the heat-fusible resin layers on both sides of the adhesive film may be the same material or different materials, and are appropriately selected in accordance with the materials constituting the heat-fusible resin layer 53 of the outer film 50 and the materials constituting the main body 70A. Preferably, the material constituting the heat-fusible resin layer on the side of the adhesive film that is bonded to the main body 70A is 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 it is a polyolefin graft-modified with an unsaturated carboxylic acid or its anhydride. Specifically, examples of acid-modified polyolefins include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylene such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymer of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymer of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred, and polypropylene is particularly preferred.

[0063] Furthermore, the polyolefin that is acid-modified may be a cyclic polyolefin. For example, a carboxylic acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a portion of the monomers constituting the cyclic polyolefin with an α,β-unsaturated carboxylic acid or its anhydride, or by block polymerization or graft polymerization of an α,β-unsaturated carboxylic acid or its anhydride to a cyclic polyolefin.

[0064] The acid-modified cyclic polyolefin is a copolymer of an olefin and a cyclic monomer. Examples of olefins that are constituent monomers of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Examples of cyclic monomers that are constituent monomers of 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 more preferred. Styrene can also be used as a constituent monomer. Examples of carboxylic acids or their anhydrides used for acid modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride. It is preferable that the heat-sealable resin layer on the side of the adhesive film that is adhered to the outer film 50 is made of the same material as the material that constitutes the heat-sealable resin layer 53 of the outer film 50. It is preferable that the adhesive film has adhesive properties. When an adhesive film has adhesive properties, when joining the outer film 50 and the main body 70A, the position of one part relative to the other is less likely to shift. Imparting adhesive properties to an adhesive film can be achieved by incorporating an adhesive-imparting resin into the heat-sealable resin layer of the adhesive film.

[0065] The heat-resistant base layer may be a heat-resistant film or a nonwoven fabric. Examples of materials constituting the heat-resistant base layer include polyolefin resins, polyamide resins, polyester resins, epoxy resins, acrylic resins, fluororesins, silicon resins, phenolic resins, polyetherimides, polyimides, polycarbonates, and mixtures or copolymers thereof. The heat-resistant base layer may have the same layer structure as the heat-sealable resin layer.

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

[0067] In this embodiment, the first sealing portion 91 is formed by heat sealing the opposing surfaces (heat-fusible resin layers 53) of the outer film 50.

[0068] The first sealing portion 91 is composed of a portion where the first edge 50A and the second edge 50B of the outer film 50 shown in Figure 3 overlap. The first sealing portion 91 extends in the longitudinal direction (FB direction) of the outer body 40. The position in the outer body 40 where the first sealing portion 91 is formed can be arbitrarily selected. In this embodiment, it is preferable that the base 91X of the first sealing portion 91 is located on the edge 43 of the boundary between the first surface 41A and the second surface 42A of the outer body 40. The base 91X of the first sealing portion 91 may be located on any surface of the outer body 40. From the viewpoint of making the energy storage device 10 compact, it is preferable that the first sealing portion 91 is folded, for example, on the first surface 41A or the second surface 42A of the outer body 40 when the energy storage device 10 is in use.

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

[0070] The seal strength of the second sealing section 92 is measured as follows. First, a cut is made in the portion of the outer film 50 that constitutes the first surface 41A of the outer body 40, forming three strip-shaped members 41X, 41Y, and 41Z (see the dashed line in Figure 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 60 in the second sealing section 92. The length of the lid 60 in the LR direction is 45 mm or more. Next, the seal strength of the strip-shaped members 41X, 41Y, and 41Z is measured by pulling the end of each strip-shaped member 41X, 41Y, and 41Z opposite to the end joined to the lid 60 upward in the UD direction (in the direction opposite to the first surface 41B). The distance between the chucks in the UD direction is 10 mm. The sealing strength of the strip members 41X, 41Y, and 41Z is the peak value of their respective sealing strengths. In this embodiment, the sealing strength of the second sealing portion 92 is the average value of the sealing strengths of the strip members 41X, 41Y, and 41Z. If the length of the lid 60 in the LR direction is less than 45 mm, three strip members with an arbitrary width X mm of less than 15 mm are formed, and the sealing strength of the three strip members is measured in the same manner as when the length of the lid 60 in the LR direction is 45 mm or more. The obtained sealing strengths are each divided by the arbitrary width X mm and multiplied by 15 to convert them to the sealing strengths of the three strip members at a width of 15 mm. The sealing strength of the second sealing portion 92 is the average value of the sealing strengths of the three strip members converted to a width of 15 mm. Note that if the lid 60 is divided into multiple parts including the long side and the short side, the sealing strength of the second sealing portion 92 is the sealing strength of the long side portion of the lid sealing portion 71 of the multiple parts.

[0071] From the viewpoint of suitably maintaining the state in which the electrode body 20 is sealed by the outer casing 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, more preferably 60 N / 15 mm or more, more preferably 70 N / 15 mm or more, and 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 body 20 is sealed by the outer casing 40 is suitably maintained even if the energy storage device 10 is 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 body 20 is sealed by the outer casing 40 is suitably maintained even if the energy storage device 10 is 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. The 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 energy storage devices> Figure 8 is a flowchart showing an example of a method for manufacturing the energy storage device 10. The method for manufacturing the energy storage device 10 includes, for example, a first step, a second step, a third step, a fourth step, and a fifth step. Steps 1 to 5 are carried out, for example, by a manufacturing apparatus for the energy storage device 10. At least a portion of steps 1 to 5 may be carried out by an operator. Note that steps 1 to 5 are names for each step of the method for manufacturing the energy storage device 10, and do not necessarily indicate the order of the steps. The order of the following steps can be changed at will.

[0073] In the first step of step S1 (film bonding step), the manufacturing apparatus bonds the main body portion 70A of the coating 70 and the heat-sealable resin layer 53 of the outer film 50 via the bonding portion 70B by heat sealing or ultrasonic sealing. In other words, the first step is the step of forming the second sealing portion 92. Hereinafter, the element to which the coating 70 and the outer film 50 are bonded will be referred to as an intermediate.

[0074] The second step of step S2 is performed before or after the first step. In the second step, the manufacturing apparatus electrically connects the lid 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 body 20, with the lid body 80 connected, into the intermediate body through the opening 70YA of the main body 70A of the intermediate body. Upon completion of the third step, the electrode body 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 step (closing step) of step S4 is performed after the third step. In the fourth step, the manufacturing apparatus joins the main body 70A and the lid body 80, for example, by welding. The main body 70A and the lid body 80 may also be joined by crimping, press-fitting, shrink-fitting, crimp welding, pressure welding, brazing, or adhesive. When the main body 70A and the lid body 80 are fixed by crimping, it is preferable to place an adhesion assist member between the main body 70A and the lid body 80. The adhesion assist member may be, for example, foam material, sponge, resin, or rubber.

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

[0078] Figure 9 is a flowchart illustrating another example of a method for manufacturing the energy storage device 10. The method for manufacturing the energy storage device 10 includes, for example, steps 11, 12, 13, 14, 15, and 16. Steps 11 to 16 are carried out, for example, by a manufacturing apparatus for the energy storage device 10. At least a portion of steps 11 to 16 may be carried out by an operator. Note that steps 11 to 16 are merely names for the steps in the manufacturing method of the energy 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 11th step of step S11, the manufacturing apparatus places a pair of coverings 70 to the side of the electrode body 20.

[0080] Step S12, the 12th step, is performed after the 11th step. In the second step, the manufacturing apparatus wraps the outer film 50 around the electrode body 20 and the coating 70 while tension is applied to the outer film 50, while restricting the movement of the electrode body 20 and the coating 70 with restricting means. The restricting means is, for example, a groove into which the electrode body 20 and the coating 70 are fitted. The restricting means may also be a device that applies an external force to the electrode body 20 and the coating 70 to prevent them from moving. The restricting means may also be a device that applies a force to the electrode body 20 and the coating 70 in the opposite direction to the direction in which the outer film 50 is pulled. The restricting means may also include a roller that runs on the outer film 50 while the outer film 50 is being pulled in order to remove wrinkles in the outer film 50.

[0081] Step S13, the 13th step (film bonding step), is performed after the 12th step. In the 13th step, the manufacturing apparatus bonds the main body 70A of the covering 70 and the heat-sealable resin layer 53 of the outer film 50 via the bonding portion 70B by heat sealing or ultrasonic sealing. In other words, the 13th step is the step of forming the second sealing portion 92.

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

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

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

[0085] <1-3. Function and Effects of Energy Storage Devices> According to the energy storage device 10, the lid 60 comprises a covering 70 and a lid body 80, so the electrode body 20 can be sealed by fitting the lid body 80 into the opening 70YA of the covering 70. Since the electrode body 20 can be sealed at any time during the manufacturing process of the energy storage device 10, it can be manufactured using a variety of procedures.

[0086] [2. Variant] The embodiments described above are illustrative of possible forms of the energy storage device, cover, covering, and method for manufacturing the energy storage device according to the present invention, and are not intended to limit their forms. The energy storage device, cover, covering, and method for manufacturing the energy storage device according to the present invention may take forms different from those illustrated in the embodiments. One example is a form in which some of the configurations of the embodiments are replaced, modified, or omitted, or a form in which new configurations are added to the embodiments. Several examples of modifications of the embodiments are shown below. Note that the following modifications can be combined with each other as long as they do not contradict each other technically.

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

[0088] In the first modified example, from the viewpoint of suitably joining the main body 70A and the lid body 80, at least a portion of the surface of the lid seal portion 71, in other words, 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 provides corrosion resistance (e.g., acid resistance, alkali resistance, etc.) to the lid seal portion 71 by performing corrosion prevention treatments on the surface of the lid seal portion 71, such as hot water modification treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or coating agent application. Specifically, the corrosion-resistant coating means 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), etc. One type of treatment may be performed to form the corrosion-resistant coating, or two or more types may be combined. Furthermore, it is possible to create not just a single layer but multiple layers. In addition, among these treatments, hydrothermal modification and anodic oxidation are treatments that dissolve the surface of the metal foil with a treatment agent and form a metal compound with excellent corrosion resistance. Note that these treatments may also be included in the definition of chemical conversion treatment. Also, if the lid seal portion 71 is equipped with a corrosion-resistant coating, the lid seal portion 71 is defined to include the corrosion-resistant coating.

[0089] <2-2. Second variation> In the above embodiment, the coating 70 may be arranged such that the second surface 70Y of the main body portion 70A faces the electrode body 20. In the second modified example, the heat seal bar holder can be placed in the space 79 in the first step shown in Figure 8 or the 13th step shown in Figure 9, so that the first step or the 13th step can be carried out suitably.

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

[0091] <2-4. Fourth variation> In the above embodiment, the outer film 50 of the energy storage device 10 may extend outward in the FB direction beyond at least one of the two lids 60. The electrode body 20 is sealed when the portion of the outer film 50 that extends outward beyond the lids 60 is closed. The portion of the outer film 50 that extends outward beyond the lids 60 may be folded inward so that the outer surfaces of the outer film 50 come into contact with each other, as in a Goebeltop type container, or it may be folded toward any surface of the outer body 40, as in a brick type container.

[0092] <2-5. Fifth variation> In the above embodiment, the outer casing 40 may not have one of the two lids 60. In this modification, in the FB direction, in the portion of the outer casing 40 where the lid 60 is omitted, the electrode body 20 is sealed by closing the portion of the outer film 50 that extends outward from the electrode body 20. The portion of the outer film 50 that extends outward from the electrode body 20 may be folded to form a Goebeltop type container or a brick type container, similar to the seventh modification.

[0093] <2-6. Sixth Variation> In the above embodiment, the outer shape of the exterior body 40 can be arbitrarily changed. 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 was wrapped in one outer film 50, but it may be wrapped in two or more outer films 50. [Explanation of Symbols]

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

Claims

1. Electrode body and The electrode body is enclosed by an outer casing, The exterior body is, The outer film enclosing the electrode body, It has a lid that seals the electrode body together with the outer film, The aforementioned cover is The lid body is made of a metal material and is a metal molded product, It has a covering that is joined to the outer film and covers at least a part of the lid body, The covering has a main body portion including a lid seal portion that is joined to the outer film, The main body is a metal molded product composed of a metal material, and when the total mass of the material constituting the main body is considered to be 100%, the content of the metal material is 50% by mass or more. Energy storage device.

2. The volume of the main body is smaller than the volume of the lid body. The energy storage device according to claim 1.

3. The aforementioned covering body, The aforementioned lid sealing portion, It has a protruding portion that extends from the lid sealing portion and defines a portion that covers the edge of the lid body. The energy storage device according to claim 1 or 2.

4. The covering further has a joint that covers at least a portion of the edge of the main body. The energy storage device according to claim 1 or 2.

5. The aforementioned joint is a resin molded product. The energy storage device according to claim 4.

6. The aforementioned joint is an adhesive film that can be bonded to metal materials and resin materials. The energy storage device according to claim 4.

7. The aforementioned joint is an adhesive. The energy storage device according to claim 4.

8. A lid used as an outer casing for an energy storage device, The lid body is made of a metal material and is a metal molded product, The exterior film constituting the exterior body is joined to a covering body that covers at least a portion of the edge of the lid body, The covering has a main body portion including a lid seal portion that is joined to the outer film, The main body is a metal molded product composed of a metal material, and when the total mass of the material constituting the main body is considered to be 100%, the content of the metal material is 50% by mass or more. Cover.

9. A covering that constitutes a lid used as an outer casing for an energy storage device, The lid has a lid body made of a metal material, The covering has a main body portion including a lid seal portion that is joined to the outer film constituting the outer body, and is configured to cover at least a part of the edge of the lid body. The main body is a metal molded product composed of a metal material, and when the total mass of the material constituting the main body is considered to be 100%, the content of the metal material is 50% by mass or more. Covering body.

10. A method for manufacturing an energy storage device, The aforementioned energy storage device is Electrode body and The electrode body is enclosed by an outer casing, The exterior body is, The outer film enclosing the electrode body, It has a lid that seals the electrode body together with the outer film, The aforementioned cover is The lid body is made of a metal material and is a metal molded product, It has a covering that is joined to the outer film and covers at least a part of the lid body, The covering has a main body portion including a lid seal portion that is joined to the outer film, The main body is a metal molded product composed of a metal material, and when the total mass of the material constituting the main body is considered to be 100%, the content of the metal material is 50% by mass or more. The method for manufacturing the aforementioned energy storage device is as follows: A film bonding step for joining the outer film and the covering, The process includes a closing step, which is performed after the film bonding step, and which joins the covering body and the lid body. A method for manufacturing energy storage devices.

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