Cover, energy storage device, method for manufacturing an energy storage device

Abstract

The present invention provides a lid that is resistant to deformation, a power storage device equipped with this lid, and a method for manufacturing the power storage device. [Solution] The cover is a cover that constitutes the outer casing of the energy storage device. The cover comprises a base, a wall protruding from the base, and ribs extending from one of the base and the wall toward the other.

Description

Technical Field

[0001] The present invention relates to a lid body, a power storage device, and a method for manufacturing the power storage device.

Background Art

[0002] Patent Document 1 discloses an example of a power storage device. This power storage device includes an electrode body and an exterior body that seals the electrode body. The exterior body has an exterior film that wraps the electrode body and a lid body that is joined to the exterior film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above power storage device, for example, when the lid body is deformed, the lid body and the exterior film cannot be suitably joined, and there is a risk that the sealing performance of the exterior body will deteriorate. Note that the deformation of the lid body occurs, for example, when an external force acts on the lid body and when there are molding defects or the like when the lid body is manufactured by injection molding.

[0005] An object of the present invention is to provide a lid body that is suppressed from being deformed, a power storage device including this lid body, and a method for manufacturing this power storage device.

Means for Solving the Problems

[0006] The lid body according to the first aspect of the present invention is a lid body that constitutes an exterior body of a power storage device, and includes a base portion, a wall portion that protrudes from the base portion, and a rib that extends from one of the base portion and the wall portion toward the other.

[0007] A lid according to a second aspect of the present invention is a lid according to a first aspect, wherein the ribs are in contact with the base and the wall.

[0008] A lid according to a third aspect of the present invention is a lid according to the first or second aspect, wherein the rib is joined to at least one of the base and the wall.

[0009] A lid according to a fourth aspect of the present invention is a lid according to any one of the first to third aspects, wherein the wall portion has a first wall surface joined to an exterior film which is an element constituting the exterior body, and a second wall surface opposite to the first wall surface, and the rib extends from one of the base portion and the second wall surface toward the other.

[0010] A lid according to the fifth aspect of the present invention is a lid according to any one of the first to fourth aspects, wherein the base portion comprises an output portion made of a conductive material and a covering portion made of a resin material that covers a part of the output portion.

[0011] A sixth 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 base, a wall protruding from the base and joined to the outer film, and a rib extending from one of the base and the wall toward the other.

[0012] A method for manufacturing an energy storage device according to a seventh 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 encloses the electrode body and a lid that seals the electrode body together with the outer film, and the lid comprises a base, a wall protruding from the base and joined to the outer film, and a rib extending from one of the base and the wall toward the other. The method for manufacturing the energy storage device includes the step of positioning the lid relative to the electrode body. [Effects of the Invention]

[0013] According to the lid body, the power storage device, and the method for manufacturing the power storage device of the present invention, it is possible to suppress deformation of the lid body.

Brief Description of the Drawings

[0014] [Figure 1A] Perspective view of the power storage device of the embodiment. [Figure 1B] Diagram regarding the method for measuring the seal strength of the second sealing portion of the power storage device of FIG. 1A. [Figure 2] Cross-sectional view showing the layer structure of the exterior film provided in the power storage device of FIG. 1A. [Figure 3] Diagram of the state where the exterior film provided in the power storage device of FIG. 1A is spread out. [Figure 4] Perspective view of the lid body provided in the power storage device of FIG. 1A. [Figure 5] Cross-sectional view taken along line D5-D5 of FIG. 1A. [Figure 6] Flowchart showing an example of the method for manufacturing the power storage device of FIG. 1A. [Figure 7] Cross-sectional view of the lid body provided in the power storage device of the first modification example. [Figure 8] Cross-sectional view of the lid body provided in the power storage device of the second modification example. [Figure 9] Cross-sectional view of the lid body provided in the power storage device of the third modification example. [Figure 10] Cross-sectional view of the lid body provided in the power storage device of the fourth modification example. [Figure 11] Cross-sectional view of the lid body provided in another example of the power storage device of the fourth modification example. [Figure 12] Cross-sectional view of the base portion of the lid body provided in the power storage device of the fifth modification example.

Modes for Carrying Out the Invention

[0015] Hereinafter, while referring to the drawings, a power storage device according to an embodiment of the present invention will be described. In this specification, the numerical range indicated by "~" means "or more" and "or less". For example, the notation 2~15 mm means 2 mm or more and 15 mm or less.

[0016] [Embodiment] <1-1. Configuration of Power Storage Device> FIG. 1A is a plan view schematically showing a power storage device 10 of an embodiment. FIG. 1B is a diagram regarding a method for measuring the seal strength of the second sealing portion 100B of the power storage device 10 in FIG. 1A. FIG. 2 is a cross-sectional view showing the layer structure of an exterior film 50 included in the power storage device 10 in FIG. 1A. FIG. 3 is a view of the exterior film 50 included in the power storage device 10 in FIG. 1A in a spread state. FIG. 4 is a perspective view of a lid body 60 included in the power storage device 10 in FIG. 1A. FIG. 5 is a cross-sectional view taken along line D5-D5 in FIG. 1A. In FIG. 1A, the direction of arrow UD indicates the thickness direction of the power storage device 10, the direction of arrow LR indicates the width direction of the power storage device 10, and the direction of arrow FB indicates the depth direction of the power storage device 10. The directions indicated by each of the arrows UDLRFB are common in each of the subsequent figures.

[0017] The power storage device 10 includes an electrode body 20 including a current collector 30 and an exterior body 40. The electrode body 20 includes, for example, electrodes (positive electrode and negative electrode) constituting a power storage member such as a lithium ion battery, a capacitor, an all-solid-state battery, a semi-solid-state battery, a quasi-solid-state battery, a polymer battery, an all-resin battery, a lead storage battery, a nickel-hydrogen storage battery, a nickel-cadmium storage battery, a nickel-iron storage battery, a nickel-zinc storage battery, a silver oxide-zinc storage battery, a metal-air battery, a polyvalent cation battery, or a capacitor, and a separator and the like. In the present embodiment, the shape of the electrode body 20 is a substantially rectangular parallelepiped. Note that the "substantially rectangular parallelepiped" includes, in addition to a perfect rectangular parallelepiped, a solid that can be regarded as a rectangular parallelepiped by modifying the shape of a part of the outer surface, for example. The shape of the electrode body 20 may be, for example, a cylinder or a polygonal prism. One end portion 31 of the current collector 30 (see FIG. 5) is connected to an output portion 71 of a lid body 60 described later.

[0018] The outer casing 40 seals the electrode body 20. The outer casing 40 has an outer film 50 and a lid 60. The outer film 50 wraps around the electrode body 20. In this embodiment, the outer film 50 is wrapped around the electrode body 20. The lid 60 is positioned to the side of the electrode body 20 in the FB direction. In another example, the electrode body 20 may be housed inside a cylindrical outer film 50 with openings formed at both ends in the FB direction, and the openings may be closed by the lid 60. In yet another example, the electrode body 20 may be housed inside a cylindrical outer film 50 with the lid 60 connected, and the openings may be closed by the lid 60.

[0019] For example, one method is to form a housing portion (recess) for housing the electrode body 20 in the outer film 50 through cold forming. However, it is not always easy to form a deep housing portion by such a method. If one attempts to form a deep housing portion (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 the thickness of the electrode body 20. 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 it is necessary to apply high pressure uniformly from the outside surface of the battery in order to exert 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.

[0020] 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.

[0021] The outer film 50 may be composed of a laminate comprising at least a barrier layer 52 and a heat-fusible resin layer 53 in that order. In this laminate, the base layer 51 is a layer provided as needed, with the side of the barrier layer 52 opposite to the heat-fusible resin layer 53 being the outermost layer, and the heat-fusible resin layer 53 being the innermost layer.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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. Examples of soft aluminum alloy foils include aluminum alloy foils having compositions specified in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Silicon, magnesium, copper, manganese, etc., may also be added as needed. Softening can be achieved through annealing or other treatments. From the viewpoint of improving the mechanical strength of the outer film 50, it is more preferable that the aluminum alloy foil be 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 H4160:1994A8021H-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.

[0027] 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.

[0028] Specific examples of austenitic stainless steels that make up stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred among these.

[0029] 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 5 to 1000 μm. The thickness of the barrier layer 52 is preferably about 85 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, and particularly preferably about 35 μm or less. 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.

[0030] 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.

[0031] 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.

[0032] 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 resin films made of 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 1000 μm, and more preferably 40 to 150 μm, from the viewpoint of sealing properties and strength.

[0033] 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.

[0034] 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.

[0035] When the buffer layer is made of rubber, the lower limit of the buffer layer thickness is preferably 0.5 mm, more preferably 1.0 mm. When the buffer layer is made of rubber, the upper limit of the buffer layer thickness is preferably 10 mm, more preferably 5.0 mm, more preferably 2.0 mm. When the buffer layer is made of rubber, the preferred range of the buffer layer thickness is 1.0 mm to 2.0 mm, 1.0 mm to 5.0 mm, 1.0 mm to 10 mm, 0.5 mm to 2.0 mm, 0.5 mm to 5.0 mm, and 0.5 mm to 10 mm.

[0036] 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.

[0037] The cover 60 has a base portion 70, a wall portion 80, and a rib 90.

[0038] The outer shape of the base portion 70 can be arbitrarily selected as long as it is a shape that can seal the electrode body 20. In the example shown in Figure 4, the outer shape of the base portion 70 is rectangular. The outer shape of the base portion 70 may be circular, elliptical, square, triangular, or a polygon with pentagons or more. The base portion 70 has a first surface 70A and a second surface 70B. The first surface 70A faces the external space. The second surface 70B is the surface opposite to the first surface 70A in the FB direction. The second surface 70B faces the electrode body 20. The cover 60 may be arranged so that the first surface 70A faces the electrode body 20, in other words, so that the second surface 70B faces the external space. The base portion 70 includes an output section 71 and a covering section 72.

[0039] The output unit 71 is an element that outputs power to external equipment. The output unit 71 is connected to one end 31 of the current collector 30. The outer shape of the output unit 71 can be arbitrarily selected. In the example shown in Figure 4, the outer shape of the output unit 71 is rectangular.

[0040] In this embodiment, the output unit 71 is configured to include a conductive material. "Configured to include a conductive material" means that, when the total mass of the materials constituting the output unit 71 is considered to be 100% by mass, the content of the conductive material is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. That is, the materials constituting the output unit 71 may include materials other than conductive materials in addition to the conductive material. The output unit 71 configured to include a conductive material preferably has a corrosion-resistant coating as described in the barrier layer 52.

[0041] The conductive material constituting the output unit 71 is, for example, a metallic material. The metallic material constituting the output unit 71 is, for example, aluminum, aluminum alloy, nickel, copper, or copper alloy. For example, if the electrode body 20 is a lithium-ion battery, the output unit 71 connected to the positive electrode is preferably made of aluminum or an aluminum alloy. The output unit 71 connected to the negative electrode is preferably made of nickel, copper, or a copper alloy. The material constituting the output unit 71 connected to the negative electrode may be copper with nickel plating. The material constituting the output unit 71 may also include recycled metallic materials.

[0042] The covering portion 72 covers a part of the output portion 71. In the example shown in Figure 4, the covering portion 72 covers the entire outer edge of the output portion 71. The outer shape of the covering portion 72 can be arbitrarily selected. In the example shown in Figure 4, the outer shape of the covering portion 72 is rectangular. The covering portion 72 has a through hole 72X formed in the center that penetrates the first surface 70A and the second surface 70B.

[0043] In this embodiment, the coating portion 72 is composed of a resin material. Here, "composed of a resin material" means that when the total mass of the materials constituting the coating portion 72 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 coating portion 72 may contain materials other than resin materials 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, 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 coating portion 72 may be molded by any molding method, or it may be manufactured by cutting.

[0045] The resin material included in the material constituting the coating portion 72 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 portion 72 preferably contains multiple types of amide lubricants. Furthermore, the resin material included in the material constituting the coating portion 72 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 portion 72 may be a polyolefin resin to which a propylene-based elastomer with a melting point higher than 150°C has been added. The main component refers to a material that accounts for, for example, 35% or more by mass, 50% or more by mass, 90% or more by mass, or 95% or more by mass of the materials included in the constituent material.

[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 coating portion 72 to temperature changes can be improved.

[0049] The melt mass flow rate of the resin material contained in the material constituting the coating portion 72 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 measurement temperature for the melt mass flow rate is 230°C.

[0050] The thickness of the output section 71 and the thickness of the covering section 72 in the FB direction can be arbitrarily selected. The thickness of the output section 71 in the FB direction may be thicker than the thickness of the covering section 72, thinner than the thickness of the covering section 72, or equal to the thickness of the covering section 72. In the example shown in Figure 4, the thickness of the output section 71 in the FB direction is substantially equal to the thickness of the covering section 72 in the FB direction. In other words, the first surface 70A of the output section 71 and the first surface 70A of the covering section 72 are flush. The second surface 70B of the output section 71 and the second surface 70B of the covering section 72 are flush.

[0051] The wall portion 80 protrudes from the outer peripheral edge of the covering portion 72. The direction in which the wall portion 80 protrudes can be arbitrarily selected. In the example shown in Figure 5, etc., the wall portion 80 protrudes in the FB direction from the outer peripheral edge of the covering portion 72 toward the electrode body 20. The wall portion 80 may also protrude in the FB direction from the outer peripheral edge of the covering portion 72 toward the opposite direction from the electrode body 20, in other words toward the external space. In a side view of the cover 60, the wall portion 80 may protrude from the outer peripheral edge of the covering portion 72 in a direction intersecting the FB direction.

[0052] The wall portion 80 is preferably made of a resin material. The definition of "made of a resin material" for the wall portion 80 is the same as the definition of "made of a resin material" for the covering portion 72. The resin material included in the material constituting the wall portion 80 can be the same as the resin material exemplified for the material constituting the covering portion 72. From the viewpoint of easily molding the lid 60, it is preferable that the resin material included in the material constituting the wall portion 80 and the resin material included in the material constituting the covering portion 72 are the same.

[0053] The wall portion 80 has a first wall surface 80A and a second wall surface 80B. The first wall surface 80A is the surface that is joined to the outer film 50. In this embodiment, the first wall surface 80A is joined to the heat-sealable resin layer 53 of the outer film 50 by heat sealing. The first wall surface 80A may also be joined to the outer film 50 by adhesive. The second wall surface 80B is the surface opposite to the first wall surface 80A.

[0054] The wall portion 80 includes a first joining wall 81, a second joining wall 82, a third joining wall 83, and a fourth joining wall 84. The first joining wall 81 constitutes the upper surface of the lid 60. In a front view of the lid 60, the first joining wall 81 extends in a first direction (in this embodiment, the LR direction). The second joining wall 82 and the third joining wall 83 connect to the first joining wall 81 and constitute the side surface of the lid 60. In a front view of the lid 60, the second joining wall 82 and the third joining wall 83 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 60, 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 60. The fourth joining wall 84 constitutes the lower surface of the lid 60. The fourth joint wall 84 extends in the first direction (in this embodiment, the LR direction) when viewed from the front of the lid 60.

[0055] In this embodiment, the thickness of the first to fourth joining walls 81 to 84 is substantially constant in the FB direction. The thickness of the first to fourth joining walls 81 to 84 may differ in the FB direction. For example, at least one of the first to fourth joining walls 81 to 84 may have a tapered shape in which the thickness increases as it approaches the electrode body 20 in the FB direction, or it may have a tapered shape in which the thickness decreases. When the first to fourth joining walls 81 to 84 have a tapered shape, from the viewpoint of suppressing an increase in the internal pressure of the outer casing 40, it is preferable that the tapered shape is one in which the thickness increases as it approaches the electrode body 20. From the viewpoint of suppressing a decrease in the strength of the lid 60, it is preferable that the first joining wall 81 and the fourth joining wall 84, which have a long length in the LR direction among the wall portions 80, have a constant thickness in the FB direction, in other words, do not have a tapered shape.

[0056] The wall portion 80 further includes boundaries 85, 86, 87, and 88. Boundary 85 is the boundary between the first joint wall 81 and the second joint wall 82. Boundary 86 is the boundary between the first joint wall 81 and the third joint wall 83. Boundary 87 is the boundary between the fourth joint wall 84 and the second joint wall 82. Boundary 88 is the boundary between the fourth joint wall 84 and the third joint wall 83. The shape of boundaries 85 to 88 may be angular, or it may be rounded by R processing. In this embodiment, boundaries 85 to 88 are angular. If the shape of boundaries 85 to 88 is rounded, it is preferable that the radius of curvature of boundaries 85 to 88 is in the range of greater than 0 mm to 0.5 mm or less.

[0057] 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. The minimum thickness of the covering portion 72 and wall portion 80 of the lid 60 is, for example, 0.3 mm, more preferably 3.0 mm, and even more preferably 4.0 mm. The maximum thickness of the covering portion 72 and wall portion 80 of the lid 60 is, for example, 20 mm, more preferably 15 mm, even more preferably 10 mm, and even more preferably 7.0 mm. The maximum thickness of the covering portion 72 and wall portion 80 of the lid 60 may be 20 mm or more. The preferred thickness ranges for the covering portion 72 and wall portion 80 of the lid 60 are 0.3mm to 20mm, 0.3mm to 15mm, 0.3mm to 10mm, 0.3mm to 7.0mm, 3.0mm to 20mm, 3.0mm to 15mm, 3.0mm to 10mm, 3.0mm to 7.0mm, 4.0mm to 20mm, 4.0mm to 15mm, 4.0mm to 10mm, and 4.0mm to 7.0mm. In this embodiment, the covering portion 72 and wall portion 80 are not composed solely of film as defined by the JIS (Japanese Industrial Standards) [Packaging Terminology] standard. The thickness of the covering portion 72 and wall portion 80 of the lid 60 may vary depending on the part. For example, if the thickness of the covering portion 72 of the lid 60 varies depending on the part, the thickness of the covering portion 72 of the lid 60 is the thickness of the thickest part of the covering portion 72. For example, if the thickness of the wall portion 80 of the lid 60 differs depending on the part, the thickness of the wall portion 80 of the lid 60 is the thickness of the thickest part of the wall portion 80.

[0058] The lid 60 may deform relative to one of its components, such as the base 70 or the wall 80, due to external forces acting on the lid 60 or molding defects during injection molding of the lid 60. The ribs 90 have the function of suppressing deformation of the lid 60.

[0059] The rib 90 extends from one of the base portion 70 and the wall portion 80 toward the other. From the viewpoint of suitably suppressing deformation of the lid 60, it is preferable that the rib 90 extends from one of the second surface 70B of the base portion 70 and the second wall surface 80B of the wall portion 80 toward the other. The rib 90 may also extend from one of the second surface 70B of the base portion 70 and any point on the wall portion 80 toward the other. From the viewpoint of suitably suppressing deformation of the lid 60, it is preferable that the rib 90 is in contact with the base portion 70 and the wall portion 80. The rib 90 does not have to be in contact with the base portion 70 or the wall portion 80. From the viewpoint of suitably suppressing deformation of the lid 60, it is preferable that the rib 90 is joined to at least one of the base portion 70 and the wall portion 80. The rib 90 does not have to be joined to the base portion 70 or the wall portion 80. In this embodiment, the rib 90 is joined to the base portion 70 and the wall portion 80.

[0060] The number of ribs 90 on a single cover 60 can be arbitrarily selected. In the example shown in Figure 4, a single cover 60 has 16 ribs 90. In the example shown in Figure 4, the second wall surface 80B of the first joint wall 81 and the second surface 70B of the covering portion 72 are connected by 5 ribs 90. The second wall surface 80B of the second joint wall 82 and the second surface 70B of the covering portion 72 are connected by 3 ribs 90. The second wall surface 80B of the third joint wall 83 and the second surface 70B of the covering portion 72 are connected by 3 ribs 90. The second wall surface 80B of the fourth joint wall 84 and the second surface 70B of the covering portion 72 are connected by 5 ribs 90. The ribs 90 may extend from one of the wall portion 80 and the second surface 70B of the output portion 71 toward the other. A single lid 60 may have 1 to 15 or 17 or more ribs 90.

[0061] When a single lid 60 has multiple ribs 90, the spacing between adjacent ribs 90 can be arbitrarily selected. From the viewpoint of suitably suppressing deformation of the lid 60, the spacing between adjacent ribs 90 is preferably 15 mm or less, and more preferably 10 mm or less.

[0062] If the rib 90 extends from the second wall surface 80B, the rib 90 can be formed at any position on the second wall surface 80B. From the viewpoint of moldability of the lid 60, it is preferable that the rib 90 is not formed at the corners of the boundary of the second wall surface 80B of the continuous wall portion 80.

[0063] The shape of the rib 90 can be arbitrarily selected as long as it can suppress deformation of the lid 60. In the example shown in Figure 4, the shape of the rib 90 is a triangular plate shape. In this embodiment, the entirety of any one side of the rib 90 is joined to the second wall surface 80B of the wall portion 80. The entirety of another arbitrary side of the rib 90 is joined to the second surface 70B of the covering portion 72. The shape of the rib 90 may be a disc shape, an elliptical plate shape, a square plate shape, or a polygonal plate shape with pentagons or more. If one lid 60 has multiple ribs 90, the shapes of the multiple ribs 90 may be the same, or at least one may be different.

[0064] The thickness of the rib 90 can be arbitrarily selected as long as it is a thickness that can suppress deformation of the lid 60. From the viewpoint of moldability of the lid 60, it is preferable that the thickness of the rib 90 is thinner than the thickness of the wall portion 80. It is preferable that the thickness of the rib 90 is 2 / 3 or less of the thickness of the wall portion 80, and more preferably half or less. When the thickness of the rib 90 is thinner than the thickness of the wall portion 80, deformation of the wall portion 80 during the manufacturing of the lid 60 can be suppressed. Since it is difficult for irregularities to be formed on the first wall surface 80A of the lid 60, the adhesion between the lid 60 and the outer film 50 is improved. The thickness of the rib 90 provided on the first joint wall 81 or the fourth joint wall 84 is the thickness in the LR direction. The thickness of the rib 90 provided on the second joint wall 82 or the third joint wall 83 is the thickness in the UD direction.

[0065] The manufacturing method for the lid 60 can be arbitrarily selected. For example, the lid 60 may be manufactured by injection molding the covering portion 72, the wall portion 80, and the ribs 90 onto the output portion 71. In another example, the covering portion 72 may be injection molded onto the output portion 71, and the wall portion 80 and ribs 90 may be joined to it. In yet another example, the covering portion 72 and the wall portion 80 may be injection molded onto the output portion 71, and the ribs 90 may be joined to it. In yet another example, after injection molding the covering portion 72, the wall portion 80, and the ribs 90, the output portion 71 may be placed in the through hole 72X, and the output portion 71 and the covering portion 72 may be joined. At least one of the output portion 71, the covering portion 72, the wall portion 80, and the ribs 90 may be manufactured by cutting.

[0066] In this embodiment, with the outer film 50 wrapped around the electrode body 20, the first sealing portion 100A is formed by heat sealing the opposing surfaces (heat-fusible resin layers 53) of the outer film 50 together.

[0067] The first sealing portion 100A is formed by heat sealing the portion of the outer film 50, shown in Figure 3, that includes the first edge 50A and the portion that includes the second edge 50B. The first sealing portion 100A extends in the longitudinal direction of the outer body 40. The position in the outer body 40 where the first sealing portion 100A is formed can be arbitrarily selected. In this embodiment, it is preferable that the base 100AX of the first sealing portion 100A is located on the edge 43 of the boundary between the first surface 41 and the second surface 42 of the outer body 40. The first surface 41 has a larger area than the second surface 42. The base 100AX of the first sealing portion 100A may be located on any surface of the outer body 40. In this embodiment, in a plan view, the first sealing portion 100A protrudes outward from the electrode body 20. The first sealing portion 100A may be folded toward the second surface 42 of the outer body 40, or folded toward the first surface 41.

[0068] In this embodiment, the second sealing portion 100B is formed by heat sealing the heat-fusible resin layer 53 of the outer film 50 and the first wall surface 80A of the lid 60. Hereinafter, the sealing strength between the heat-fusible resin layer 53 of the outer film 50 and the first wall surface 80A of the lid 60 may be referred to as the sealing strength (joint strength) of the second sealing portion 100B. The sealing strength of the second sealing portion 100B is the sealing strength between the heat-fusible resin layer 53 and the lid 60 in the long side portion of the first wall surface 80A, that is, the first wall surface 80A extending in the LR (width) direction in Figure 1A.

[0069] The seal strength of the second sealing section 100B is measured as follows. First, a cut is made in the portion of the outer film 50 that constitutes the first surface 41 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 100B. 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 50 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 100B 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 100B is the average value of the sealing strengths of the three strip members converted to a width of 15 mm. Furthermore, 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 100B is the sealing strength of the long side portion of the first wall surface 80A of the multiple parts.

[0070] 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 100B 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 100B 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 several years (less than 10 years). When the seal strength of the second sealing portion 100B 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 more than 10 years. The seal strength of the second sealing portion 100B is preferably 300 N / 15 mm or less. The preferred range for the seal strength of the second sealing portion 100B is 40N / 15mm to 300N / 15mm, 50N / 15mm to 300N / 15mm, 60N / 15mm to 300N / 15mm, 70N / 15mm to 300N / 15mm, or 85N / 15mm to 300N / 15mm.

[0071] <1-2. Method for manufacturing energy storage devices> Figure 6 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 that are conveniently defined for each step of the method for manufacturing the energy storage device 10 and do not necessarily mean the order of the steps. The order of steps 1 to 5 can be changed arbitrarily as long as it is not technically contradictory.

[0072] In the first step of step S11, the manufacturing apparatus places a pair of covers 60 to the side of the electrode body 20 in the FB direction.

[0073] The second step, S12, is performed after the first step. In the second step, the manufacturing apparatus connects the current collector 30 to the output section 71 of the cover 60.

[0074] The third step, S13, is performed after the second step. In the third step, the manufacturing apparatus wraps the outer film 50 around the electrode body 20 and the lid 60 while tension is applied to the outer film 50, while restricting the movement of the electrode body 20 and the lid 60 with restricting means. The restricting means is, for example, a groove into which the electrode body 20 and the lid 60 are fitted. The restricting means may also be a device that applies an external force to the electrode body 20 and the lid 60 to prevent them from moving. The restricting means may also be a device that applies a force to the electrode body 20 and the lid 60 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 from the outer film 50. Alternatively, the electrode body 20 may be housed inside the outer film 50, which is tubular in shape with openings formed at both ends in the FB direction, and after joining the current collector 30 and the output unit 71, the openings may be closed with the cover 60. In yet another example, the electrode body 20, connected to the output unit 71 of the cover 60, may be housed inside the outer film 50, which is tubular in shape with openings formed at both ends in the FB direction, and the openings may be closed with the cover 60.

[0075] The fourth step, S14, is performed after the third step. In the fourth step, the manufacturing apparatus forms the second sealing portion 110B by heat sealing the outer film 50 and the first wall surface 80A of the lid 60.

[0076] Step S15, the fifth step, is performed before or after the fourth step. In the fifth step, the manufacturing apparatus forms the first sealing portion 100A 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, while restricting the movement of the electrode body 20 and the lid body 60, and applying tension to the outer film 50.

[0077] <1-3. Function and Effects of Energy Storage Devices> The energy storage device 10 includes a cover 60. The cover 60 has ribs 90 extending from one of the base portion 70 and the wall portion 80 to the other. As a result, deformation of the cover 60 relative to the base portion 70 and the wall portion 80 is suppressed.

[0078] [2. Variant] The embodiments described above are illustrative of possible forms of the cover, energy storage device, and method for manufacturing the energy storage device according to the present invention, and are not intended to limit their forms. The cover, energy storage device, 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.

[0079] <2-1. First variation> In the above embodiment, the configuration of the lid 60 is changeable. Figure 7 is a cross-sectional view of the lid 160 of the first modified energy storage device 10.

[0080] The cover 160 includes a base 170. The cover 160 may be positioned so that the first surface 70A of the base 170 faces the external space, or so that the second surface 70B faces the electrode body 20. The base 170 may be composed of a conductive material that is substantially the entirety of the base.

[0081] <2-2. Second variation> Figure 8 is a cross-sectional view of the cover 260 of the second modified energy storage device 10. The cover 260 has a first element 270, a second element 280, and a rib 290.

[0082] The first element 270 is preferably made of a conductive material, for example. If the first element 270 is made of a conductive material, it is preferably connected to one end 31 of the current collector 30 of the electrode body 20. The first element 270 has a base 271 and a wall 272. The outer shape of the base 271 is, for example, rectangular. The wall 272 protrudes toward the electrode body 20 from the outer peripheral edge of the base 271 in the FB direction. It is preferable that the wall 272 protrudes toward the electrode body 20 from the entire outer peripheral edge of the base 271 in the FB direction.

[0083] The second element 280 is preferably made of, for example, a resin material. The second element 280 covers a portion of the first element 270. The second element 280 has a base portion 281 and a wall portion 282.

[0084] The base portion 281 covers a portion of the first surface 70A and the second surface 70B of the base portion 271, as well as a portion of the wall portion 272. The wall portion 282 is connected to the base portion 281 and covers a portion of the wall portion 272. The wall portion 282 protrudes toward the electrode body 20 in the FB direction.

[0085] The rib 290 is preferably made of, for example, a resin material. The rib 290 extends from one of the base portion 281 and the wall portion 282 toward the other. In the example shown in Figure 8, the rib 290 is joined to the base portion 281 and the wall portion 282. In the second modified example, the cover 260 may be positioned such that the first surface 70A of the base portion 271 faces the electrode body 20.

[0086] <2-3. Third Variation> Figure 9 is a cross-sectional view of the cover 360 of the third modified energy storage device 10. The cover 360 has a first element 370, a second element 380, and a rib 390.

[0087] The first element 370 is preferably made of a conductive material, for example. If the first element 370 is made of a conductive material, it is preferably connected to one end 31 of the current collector 30 of the electrode body 20. The outer shape of the first element 370 is, for example, rectangular.

[0088] The second element 380 is preferably made of, for example, a resin material. The second element 380 covers a portion of the first element 370. The second element 380 has a base portion 381 and a wall portion 382.

[0089] The base portion 381 covers a portion of the first surface 70A and the second surface 70B of the first element 370, as well as the outer periphery of the first element 370. Preferably, the base portion 381 covers the entire outer periphery of the first element 370. The wall portion 382 is connected to the base portion 381 and protrudes toward the external space in the FB direction.

[0090] The rib 390 is preferably made of, for example, a resin material. The rib 390 extends from one of the base portion 381 and the wall portion 382 toward the other. In the example shown in Figure 9, the rib 390 is joined to the base portion 381 and the wall portion 382. In the third modified example, the cover 360 may be positioned such that the first surface 70A of the first element 370 faces the electrode body 20.

[0091] <2-4. Fourth variation> Figure 10 is a cross-sectional view of the cover 460 of the fourth modified energy storage device 10. The lid 460 has a base 470, a wall 480, and ribs 490. The lid 460 may be entirely made of, for example, a resin material.

[0092] The outer shape of the base 470 is, for example, rectangular. The wall 480 projects outward into the external space from the outer edge of the base 470 in the FB direction. The rib 490 extends from one of the base 470 and the wall 480 toward the other. In the example shown in Figure 10, the rib 490 is joined to the base 470 and the wall 480.

[0093] A barrier film 400 having a moisture barrier function may be bonded to at least a portion of the first surface 70A and the second surface 70B of the base 470. In the example shown in Figure 10, the barrier film 400 is bonded to substantially the entire second surface 70B of the base 470. The barrier film 400 is a film that includes at least a barrier layer 52. The barrier film 400 may also be bonded to at least a portion of the first wall surface 80A.

[0094] In the fourth modified example, when the base 470 and wall 480 of the cover 460 are made of a resin material, it is preferable that the energy storage device 10 has an electrode terminal 400X for outputting power to the outside. The electrode terminal 400X is joined to one end 31 of the current collector 30. As shown in Figure 10, the electrode terminal 400X may be positioned between the first wall surface 80A of the wall 480 and the outer film 50 (not shown). As shown in Figure 11, the electrode terminal 400X may be positioned to penetrate the base 470 of the cover 460. In the fourth modified example, the cover 460 may be positioned so that the first surface 70A of the base 470 faces the electrode body 20.

[0095] <2-5. Fifth variation> In the above embodiment, the thickness of the base 70 was substantially constant, but the thickness of the base 70 may be partially different. As shown in Figure 12, for example, the covering portion 72 of the base 70 may include a thin portion 72A and a thick portion 72B. The thin portion 72A is formed in a predetermined range from the outer peripheral edge of the base 70. The rib 90 preferably extends from one of the thin portion 72A and the wall portion 80 toward the other.

[0096] <2-6. Sixth Variation> In the above embodiment, the entire base 70, the wall portion 80, and at least one of the ribs 90 may be made of a conductive material. If the wall portion 80 is made of a conductive material, it is preferable that the first wall surface 80A and the outer film 50 are joined via an adhesive film that is suitable for bonding the conductive material and the resin material.

[0097] The adhesive film can be arbitrarily selected as long as it is a film that can adhere the outer film 50 and the wall portion 80. 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 the specifications 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 type of 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 wall portion 80. Preferably, the material constituting the heat-fusible resin layer on the side of the adhesive film that is adhered to the wall portion 80 is an acid-modified polyolefin resin graft-modified with an acid such as maleic anhydride. Preferably, the heat-fusible resin layer on the side of the adhesive film that is adhered to the outer film 50 is the same type of material as the material constituting the heat-fusible resin layer 53 of the outer film 50.

[0098] The heat-resistant base layer can be any film made of a heat-resistant resin. For example, unstretched or stretched films of polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polymethylpentene (registered trademark), polyacetal cyclic polyolefin, polyethylene, polypropylene, etc. can be used. Polyethylene terephthalate is particularly preferred because it is inexpensive and strong.

[0099] The adhesive film is preferably tacky. When the adhesive film is tacky, the position of the adhesive film relative to the lid 60 and the outer film 50 is less likely to shift when the second sealing portion 100B is formed with the adhesive film positioned between the outer film 50 and the wall portion 80. Tackiness can be imparted to the adhesive film by incorporating a tackifying resin into the heat-fusible resin layer of the adhesive film. Examples of tackifying resins include amorphous polyolefins. Examples of amorphous polyolefins include amorphous polypropylene, or copolymers of amorphous propylene and other α-olefins. The content of the tackifying resin relative to the base material constituting the heat-fusible resin is preferably 10 to 20% by weight or less.

[0100] <2-7. Seventh 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.

[0101] <2-8. Eighth 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.

[0102] <2-9. Ninth 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.

[0103] <2-10. 10th 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]

[0104] 10: Energy storage devices 20: Electrode body 40: Exterior 50: Exterior film 60, 260, 360, 460, 560: Lid 70, 171, 181, 271, 281, 381, 470, 570: Base 71: Output section 72: Covering part 80, 172, 182, 272, 282, 382, ​​480, 580: Wall 80A: First wall 80B: Second wall 90, 190, 290, 390, 490, 590: Rib 491: First Rib 492: Second Rib

Claims

1. A cover that constitutes the outer casing of an energy storage device, The base and, A wall portion protruding from the base, The base portion and the wall portion are provided with ribs extending from one to the other. Cover.

2. The rib is in contact with the base and the wall. The lid according to claim 1.

3. The rib is joined to at least one of the base and the wall. The lid according to claim 1 or 2.

4. The aforementioned wall portion is A first wall surface which is joined to the exterior film which is an element constituting the exterior body, It has a second wall opposite to the first wall, The rib extends from the base and from one of the second wall surfaces toward the other. The lid according to claim 1.

5. The aforementioned base is, An output section comprising a conductive material, It comprises a resin material and a covering portion that covers a part of the output portion. The lid according to claim 1 or 2.

6. Electrode body and A power storage device comprising an outer casing that seals the electrode body, 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 base and, A wall portion that protrudes from the base and is joined to the exterior film, The base portion and the wall portion are provided with ribs extending from one to the other. Energy storage device.

7. 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 base and, A wall portion that protrudes from the base and is joined to the exterior film, It comprises a rib extending from one of the base portion and the wall portion toward the other, The method for manufacturing the aforementioned energy storage device is as follows: This includes the step of placing the cover on the electrode body. A method for manufacturing energy storage devices.

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