Electricity storage device, cover, and method for manufacturing electricity storage device

Abstract

An electricity storage device according to the present invention includes: an electrode body including a current collector; an exterior film covering the electrode body; and a cover body that is configured from a conductive material and seals the electrode body together with the exterior film. The cover body has: a cover main body; and a bonding portion that protrudes from the cap main body toward the electrode body and is bonded to the current collector.

Description

Technical Field

[0001] This invention relates to a storage device, a cover, and a method for manufacturing the storage device. Background Technology

[0002] Patent Document 1 discloses an example of an energy storage device. The energy storage device includes: an electrode body containing a current collector; an outer casing sealing the electrode body; and electrode terminals connected to the current collector. The outer casing includes an outer casing film covering the electrode body; and a cover engaged with the outer casing film. The electrode terminals are inserted into a through-hole formed in the cover. The ends of the current collector are engaged with the electrode terminals.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent document 1: Japanese Patent Application Publication No. 2022-123686. Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In the aforementioned energy storage device, to simplify the structure, it is considered that the cover is made of metal, and the cover and the current collector are joined, for example, by ultrasonic bonding. However, in this energy storage device, it may be difficult to easily ensure sufficient space for the arrangement of the device used to join the cover and the current collector. Therefore, poor bonding between the cover and the current collector may occur.

[0008] The purpose of this invention is to provide an energy storage device that can effectively connect a cover and a current collector, a cover for the energy storage device, and a method for manufacturing the energy storage device.

[0009] Technical means for solving problems

[0010] The energy storage device of a first aspect of the present invention includes: an electrode body comprising a current collector; an outer film covering the electrode body; and a cover body comprising a conductive material that seals the electrode body together with the outer film. The cover body has: a cover body; and a joint portion protruding from the cover body toward the electrode body and engaging with the current collector.

[0011] The energy storage device of the second aspect of the present invention is the energy storage device described in the first aspect, wherein the cover body is joined to the outer film.

[0012] The energy storage device of the third aspect of the present invention is the energy storage device described in the first or second aspect, wherein the end of the joint opposite to the cover body is spaced apart from the outer film.

[0013] The energy storage device of the fourth aspect of the present invention is the energy storage device described in any one of the first to third aspects, wherein the joint has: a first portion connected to the cover body and extending in a first direction toward the electrode body; and a second portion connected to the first portion and extending in a second direction intersecting the first direction when viewed from the side of the cover body.

[0014] The cover of the fifth aspect of the present invention is a cover that can be used as an outer casing of an energy storage device, comprising: a cover body; and a joint portion protruding from the cover body and capable of connecting to the current collector of the energy storage device.

[0015] The cover of the sixth aspect of the present invention is the cover described in the fifth aspect, wherein the joint has: a first portion connected to the cover body and extending in a first direction toward the electrode body of the energy storage device; and a second portion connected to the first portion and extending in a second direction intersecting the first direction when viewed from the side of the cover.

[0016] In a method for manufacturing an energy storage device according to a seventh aspect of the present invention, the energy storage device includes: an electrode body comprising a current collector; an outer film covering the electrode body; and a cover body made of a conductive material that, together with the outer film, seals the electrode body. The cover body has: a cover body; and a joint portion protruding from the cover body toward the electrode body and engaging with the current collector. The method for manufacturing the energy storage device includes a step of joining the joint portion and the current collector.

[0017] Invention Effects

[0018] According to the present invention, the energy storage device, the cover, and the method for manufacturing the energy storage device can effectively connect the cover and the current collector. Attached Figure Description

[0019] Figure 1A This is a perspective view of the energy storage device according to the implementation method.

[0020] Figure 1B This is a diagram showing the method for measuring the sealing strength of the second sealing part of the energy storage device in Figure 1.

[0021] Figure 2 This is a cross-sectional view showing the layer structure of the outer membrane of the energy storage device shown in Figure 1.

[0022] Figure 3 This is a diagram showing the unfolded state of the outer membrane of the energy storage device in Figure 1.

[0023] Figure 4 This is a three-dimensional view of the cover of the energy storage device shown in Figure 1.

[0024] Figure 5 yes Figure 1A A cross-sectional view along line D5-D5.

[0025] Figure 6 yes Figure 1A A cross-sectional view along line D6-D6.

[0026] Figure 7 This is a flowchart illustrating an example of a method for manufacturing the energy storage device shown in Figure 1.

[0027] Figure 8 This is a diagram of the second step in the manufacturing process of energy storage devices.

[0028] Figure 9 This is a perspective view of the cover of the energy storage device in the first modified example.

[0029] Figure 10 This is a cross-sectional view of the energy storage device in the second variation.

[0030] Figure 11 This is a cross-sectional view of the energy storage device in the third variation. Detailed Implementation

[0031] Hereinafter, an embodiment of the energy storage device of the present invention will be described with reference to the accompanying drawings. Furthermore, in this specification, the numerical range indicated by "~" means "above" or "below". For example, the description of 2 to 15 mm means 2 mm or more and 15 mm or less.

[0032] [Implementation Method]

[0033] <1-1. Structure of Energy Storage Devices>

[0034] Figure 1A This is a schematic plan view of the energy storage device 10 according to the embodiment. Figure 1B It is about Figure 1A A diagram showing the method for measuring the sealing strength of the second sealing part 100B of the energy storage device 10. Figure 2 It is shown Figure 1A A cross-sectional view of the layer structure of the outer membrane 50 of the energy storage device 10. Figure 3 yes Figure 1A A diagram showing the unfolded state of the outer membrane 50 of the energy storage device 10. Figure 4 yes Figure 1A A perspective view of the cover 60 of the energy storage device 10. Figure 5 yes Figure 1A A cross-sectional view along line D5-D5. Figure 6 yes Figure 1A A cross-sectional view along line D6-D6. Furthermore, in Figure 1AIn the diagram, arrow UD indicates the thickness direction of the energy storage device 10, arrow LR indicates the width direction of the energy storage device 10, and arrow FB indicates the depth direction of the energy storage device 10. The directions represented by arrows UD, LR, and FB are consistent in the subsequent diagrams.

[0035] The energy storage device 10 includes: an electrode body 20 containing a current collector 30; and an outer casing 40. The electrode body 20 includes, for example, electrodes (positive and negative electrodes) and a separator constituting 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-zinc oxide battery, metal-air battery, multivalent cation battery, or capacitor. In this embodiment, the electrode body 20 is approximately cuboid in shape. "Approximately cuboid" includes not only a perfect cuboid but also, for example, a three-dimensional shape that can be considered a cuboid by modifying the shape of a portion of its outer surface. The shape of the electrode body 20 can be, for example, a cylinder or a polygonal prism.

[0036] Current collector 30 (reference) Figure 6 One end 31 of the ) is connected to the cover 60.

[0037] An outer casing 40 encapsulates the electrode body 20. The outer casing 40 includes an outer casing film 50 and a cover 60. The outer casing film 50 covers the electrode body 20. In this embodiment, the outer casing film 50 is wound around the electrode body 20. The cover 60 is disposed on the side of the electrode body 20 in the FB direction. In another example, the electrode body 20 may be housed inside the outer casing film 50, which is configured as a cylinder with openings at both ends in the FB direction, and the openings may be closed with the cover 60. In yet another example, the electrode body 20, which is connected to the cover 60, may be housed inside the outer casing film 50, which is configured as a cylinder with openings, and the openings may be closed with the cover 60.

[0038] For example, there is a method of forming a receiving portion (recess) for housing the electrode body 20 in the outer film 50 by cold forming. However, forming a deep receiving portion by such a method is not necessarily easy. If the receiving portion (recess) is formed to be deep (e.g., forming depth 15 mm) by cold forming, pinholes or cracks may be generated in the outer film 50, which increases the possibility of reduced battery performance. On the other hand, the outer body 40 seals the electrode body 20 by winding 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 ineffective area between the electrode body 20 and the outer film 50 to improve the volumetric energy density of the energy storage device 10, the outer film 50 is preferably wound in a manner that contacts the outer surface of the electrode body 20. In addition, in all-solid-state batteries, from the viewpoint that a high pressure needs to be uniformly applied to the outer surface of the battery in order to maximize battery performance, it is also necessary to eliminate the space between the electrode body 20 and the outer film 50. Therefore, it is preferable that the outer film 50 is wound in a manner that contacts the outer surface of the electrode body 20.

[0039] like Figure 2 As shown, the outer film 50 is, for example, a laminate (laminated film) having a substrate layer 51, a barrier layer 52, and a heat-melting resin layer 53 in sequence. Furthermore, the outer film 50 does not necessarily contain all of these layers; for example, it may omit the barrier layer 52. That is, the outer film 50 can be made of a flexible and bendable material, such as a resin film. Additionally, the outer film 50 is preferably heat-sealed. The innermost and outermost layers of the outer film 50 can be heat-melting resin layers 53. In this case, the outer film 50 can cover the electrode body 20 and the cover body 60 by bonding the outermost layer to the innermost layer.

[0040] The outer film 50 may also be composed of a laminate in which at least a barrier layer 52 and a heat-melting resin layer 53 are sequentially disposed. In this laminate, the substrate layer 51 is a layer that can be disposed as needed, the side opposite to the heat-melting resin layer 53 side of the barrier layer 52 is the outermost layer side, and the heat-melting resin layer 53 is the innermost layer.

[0041] The overall thickness of the outer film 50 can be arbitrarily selected. From a strength point of view, the thickness of the outer film 50 is preferably 50 μm or more. From a formability or conformability point of view, the thickness of the outer film 50 is preferably 1200 μm or less. The thickness of the outer film 50 is preferably contained in the range of 50 μm or more and 1200 μm or less.

[0042] The substrate layer 51 included in the outer packaging film 50 is a layer used to impart heat resistance to the outer packaging film 50 and suppress the formation of pinholes that may occur during processing or distribution. The substrate layer 51 is configured to include at least one layer of stretched polyester resin and stretched polyamide resin. For example, by including at least one layer of stretched polyester resin and stretched polyamide resin in the substrate layer 51, the barrier layer 52 can be protected during the processing of the outer packaging film 50, and breakage of the outer packaging film 50 can be suppressed. Furthermore, from the viewpoint of increasing the elongation at break of the outer packaging film 50, the stretched polyester resin layer is preferably a biaxially stretched polyester resin layer, and the stretched polyamide resin layer is preferably a biaxially stretched polyamide resin layer. Further, from the viewpoint of excellent puncture strength or impact strength, the stretched polyester resin layer is more preferably a biaxially stretched polyethylene terephthalate (PET) film, and the stretched polyamide resin layer is more preferably a biaxially stretched nylon (ONy) film. Additionally, the substrate layer 51 may be configured to include both a stretched polyester resin layer and a stretched polyamide resin layer. From the viewpoint of film strength, the thickness of the substrate layer 51 is preferably 5 to 300 μm, and more preferably 5 to 150 μm.

[0043] The barrier layer 52 is a layer that at least inhibits the penetration of moisture. The barrier layer 52 is bonded to the substrate layer 51, for example, via an adhesive layer 54. Examples of barrier layers 52 include barrier-resistant metal foils, vapor-deposited films, and resin layers. 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 polyvinylidene chloride, polymers with trifluorochloroethylene (CTFE) as the main component, polymers with tetrafluoroethylene (TFE) as the main component, polymers containing fluoroalkyl groups, and polymers with fluoroalkyl units as the main component, as well as fluoropolymers such as ethylene-vinyl alcohol copolymers. Furthermore, examples of barrier layers 52 include resin films having at least one of these vapor-deposited films and resin layers. Multiple layers of the barrier layer 52 may also be provided. The barrier layer 52 preferably includes a layer made of a metallic material. Specifically, the metal material constituting the barrier layer 52 can be aluminum alloy, stainless steel, titanium steel, steel plate, etc. When used as a metal foil, it is preferred to include at least one of aluminum alloy foil and stainless steel foil.

[0044] In the barrier layer 52, the layer composed of the aforementioned metallic material may also contain recycled metallic materials. Examples of recycled metallic materials include aluminum alloys, stainless steel, titanium steel, or recycled steel plates. These recycled materials can be obtained using known methods. For example, recycled aluminum alloys can be obtained using the manufacturing method described in International Publication No. 2022 / 092231. The barrier layer 52 may be composed solely of recycled materials or a mixture of recycled and virgin materials. Here, recycled metallic materials refer to metallic materials that have been recycled, separated, and refined from various products used in the market and waste from manufacturing processes to become reusable. Furthermore, virgin metallic materials refer to newly refined metallic materials derived from natural metallic resources (raw materials), and are not recycled materials.

[0045] 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, such as one made of annealed aluminum alloy. From the viewpoint of further improving formability or conformability, an iron-containing aluminum alloy foil is preferred. In the iron-containing aluminum alloy foil (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass. By making the iron content 0.1% by mass or more, an outer film 50 with better formability can be obtained. By making the iron content 9.0% by mass or less, an outer film 50 with better flexibility can be obtained. In addition, silicon, magnesium, copper, manganese, etc., may be added to the aluminum alloy foil as needed. Furthermore, softening can be performed by annealing or the like. 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, such as one made of processed and cured aluminum alloy. Examples of hard aluminum alloy foils include those with compositions specified in JIS H4160:1994A8021H-H18, JIS H4160:1994A8079H-H18, JIS H4000:2014A8021P-H14, or JIS H4000:2014A8079P-H14. From the viewpoint of improving the mechanical strength of the outer film 50, the aluminum alloy foil is preferably a magnesium-containing aluminum alloy foil. In the magnesium-containing aluminum alloy foil (100% by mass), the magnesium content is preferably 0.2 to 5.6% by mass, more preferably 0.2 to 3.0% by mass. Examples of magnesium-containing aluminum alloy foils include those with the composition specified in JIS H4000:2017 A5005P-O, JIS H4000:2017 A5050P-O, and JIS H4000:2017 A5052P-O.

[0046] Furthermore, examples of stainless steel foil 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, the stainless steel foil is preferably made of austenitic stainless steel.

[0047] Specific examples of stainless steels that constitute the austenitic system of stainless steel foil include SUS 304, SUS 301, and SUS316 L, among which SUS 304 is particularly preferred.

[0048] In the case of a metal foil, the thickness of the barrier layer 52 is sufficient to at least function as a barrier layer to inhibit moisture penetration; for example, a thickness of about 5 to 1000 μm is acceptable. 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. Furthermore, the thickness of the barrier layer 52 is preferably about 9.0 μm or more, even more preferably about 20 μm or more, and even more preferably about 25 μm or more. Furthermore, preferred ranges for the thickness of the barrier layer 52 include approximately 9.0–1000 μm, approximately 9.0–1000 μm, approximately 9.0–1000 μm, approximately 9.0–1000 μm, approximately 9.0–85 μm, approximately 9.0–50 μm, approximately 9.0–40 μm, approximately 9.0–35 μm, approximately 20–85 μm, approximately 20–50 μm, approximately 20–40 μm, approximately 20–35 μm, approximately 25–85 μm, approximately 25–50 μm, approximately 25–40 μm, and approximately 25–35 μm. When the barrier layer 52 is made of aluminum alloy foil, the above-mentioned ranges are particularly preferred. Furthermore, from the viewpoint of imparting high formability and high rigidity to the outer film 50, the thickness of the barrier layer 52 is preferably about 35 μm or more, more preferably about 45 μm or more, further preferably about 50 μm or more, and even more preferably about 55 μm or more. It is also preferably about 200 μm or less, more preferably about 85 μm or less, further preferably about 75 μm or less, and even more preferably about 70 μm or less. The preferred range is 35 to 200 μm. The outer film 50 has high formability, making deep drawing easier and contributing to the increase in capacity of the energy storage device. Furthermore, while the weight of the energy storage device increases with increasing capacity, improving the rigidity of the outer film 50 also contributes to its high sealing performance. Furthermore, especially when the barrier layer 52 is made of stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less. Additionally, the thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more.In addition, preferred ranges for the thickness of stainless steel foil include approximately 10–60 μm, approximately 10–50 μm, approximately 10–40 μm, approximately 10–30 μm, approximately 10–25 μm, approximately 15–60 μm, approximately 15–50 μm, approximately 15–40 μm, approximately 15–30 μm, and approximately 15–25 μm.

[0049] Furthermore, when the barrier layer 52 is aluminum foil, to prevent dissolution, corrosion, etc., it is preferable to have a corrosion-resistant coating on at least the side opposite to the substrate layer 51. The barrier layer 52 may have a corrosion-resistant coating on both sides. Here, the corrosion-resistant coating refers to a thin film that gives the barrier layer 52 corrosion resistance (e.g., acid resistance, alkali resistance, etc.) by performing hot water conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, nickel or chromium plating treatment, or anti-corrosion treatment by applying a coating agent on the surface of the barrier layer 52. Specifically, the corrosion-resistant coating refers to a coating that improves the acid resistance of the barrier layer 52 (acid-resistant coating), a coating that improves the alkali resistance of the barrier layer 52 (alkali-resistant coating), etc. One treatment or a combination of two or more treatments can be performed to form the corrosion-resistant coating. In addition, it can be not only one layer, but also multiple layers. Furthermore, among these treatments, hot water conversion treatment and anodizing treatment are treatments that dissolve the surface of the metal foil with a treatment agent to form a metal compound with excellent corrosion resistance. Furthermore, these treatments are sometimes included in the definition of chemical conversion treatment. Additionally, when the barrier layer 52 has a corrosion-resistant coating, the layer containing the corrosion-resistant coating is considered the barrier layer 52.

[0050] The corrosion-resistant coating has the following effects: during the forming of the outer film 50, it prevents delamination between the barrier layer 52 (e.g., aluminum alloy foil) and the substrate layer 51, prevents the surface of the barrier layer 52 from dissolving and corroding due to hydrogen fluoride generated by the reaction of electrolytes and moisture, especially when the barrier layer 52 is aluminum alloy foil, prevents the dissolution and corrosion of alumina present on the surface of the barrier layer 52, and improves the adhesion (wetting) of the surface of the barrier layer 52, prevents delamination between the substrate layer 51 and the barrier layer 52 during heat sealing, and prevents delamination between the substrate layer 51 and the barrier layer 52 during forming.

[0051] The heat-melt resin layer 53 is bonded to the barrier layer 52, for example, via the adhesive layer 55. The heat-melt resin layer 53 included in the outer casing film 50 is a layer that imparts heat-sealing-based sealing properties to the outer casing film 50. Examples of heat-melt resin layers 53 include resin films composed of polyester resins such as polyethylene terephthalate resins and polybutylene terephthalate resins, polyolefin resins such as polyethylene resins and polypropylene resins, or acid-modified polyolefin resins obtained by grafting these polyolefin resins with acids such as maleic anhydride. From the viewpoint of sealing and strength, the thickness of the heat-melt resin layer 53 is preferably, for example, 20 to 300 μm, more preferably 40 to 150 μm.

[0052] The outer film 50 preferably has one or more buffering layers (hereinafter referred to as "buffer layers") located on the outer side of the heat-bonding resin layer 53, and more preferably on the outer side of the barrier layer 52. The buffer layers may be stacked on the outer side of the substrate layer 51, and the substrate layer 51 may also function as a buffer layer. When the outer film 50 has multiple buffer layers, the multiple buffer layers may be adjacent to each other or stacked with the substrate layer 51 or the barrier layer 52 in between.

[0053] The material constituting the buffer layer can be arbitrarily selected from materials with cushioning properties. Examples of cushioning materials include rubber, nonwoven fabric, or foam sheets. Examples of rubber include natural rubber, fluororubber, or silicone rubber. The rubber hardness is preferably around 20 to 90. The material constituting the nonwoven fabric is preferably a material 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 even 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 even more preferably 3000 μm. The preferred range for the thickness of the buffer layer is 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. The preferred thickness range for the buffer layer is 1000μm to 3000μm.

[0054] When the buffer layer is made of rubber, the lower limit of the buffer layer thickness is preferably 0.5 mm. When the buffer layer is made of rubber, the upper limit of the buffer layer thickness is preferably 10 mm, more preferably 5 mm, and even more preferably 2 mm. When the buffer layer is made of rubber, the preferred range of the buffer layer thickness is 0.5 mm to 10 mm, 0.5 mm to 5 mm, and 0.5 mm to 2 mm.

[0055] When the outer film 50 has a buffer layer, the buffer layer functions as a buffer, thus suppressing damage to the outer film 50 caused by the impact of the energy storage device 10 falling or by the operation during the manufacturing of the energy storage device 10.

[0056] The cover 60 has a cover body 70, a joint 80, and a cover 90 that covers a portion of the cover body 70. The cover 60 can be manufactured, for example, by injection molding the cover 90 relative to the cover body 70.

[0057] The cover body 70 and the joint portion 80 are constructed using a conductive material. "Constructed using a conductive material" means that when the total mass of the materials constituting the cover body 70 and the joint portion 80 is 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 cover body 70 and the joint portion 80 may contain materials other than the conductive material. The cover body 70 and the joint portion 80 preferably have the corrosion-resistant coating described in the barrier layer 52.

[0058] The conductive materials constituting the cover body 70 and the connecting portion 80 are, for example, metallic materials. The metallic materials constituting the cover body 70 and the connecting portion 80 are, for example, aluminum, aluminum alloy, nickel, copper, or copper alloy. For example, in the case where the electrode body 20 is a lithium-ion battery, the cover body 70 and the connecting portion 80 connected to the positive electrode are preferably made of aluminum or aluminum alloy. The cover body 70 and the connecting portion 80 connected to the negative electrode are preferably made of nickel, copper, or copper alloy. The material of the cover body 70 and the connecting portion 80 connected to the negative electrode can also be a material that has been nickel-plated onto copper. The materials constituting the cover body 70 and the connecting portion 80 can include recycled metallic materials. The cover body 70 has a base 71 and a cover portion 72.

[0059] like Figure 4 and Figure 5 The base 71 shown is, for example, a rectangular plate with a first surface 71A and a second surface 71B. The first surface 71A faces outward. The second surface 71B is the surface opposite to the first surface 71A. The second surface 71B is opposite to the electrode body 20.

[0060] Cover portion 72 is covered by cover body 90. Cover portion 72 is a frame-shaped part that rises from the first surface 71A of base portion 71. Cover portion 72 has a first cover portion 72A, a second cover portion 72B, and a third cover portion 72C. The first cover portion 72A forms the upper surface of cover body 70. The first cover portion 72A extends in a first direction (LR direction in this embodiment) in the front view of cover body 70. The second cover portion 72B and the third cover portion 72C are connected to the first cover portion 72A and form the side surface of cover body 70. The second cover portion 72B and the third cover portion 72C extend in a second direction (UD direction in this embodiment) that intersects the first direction in the front view of cover body 70. In this embodiment, the first direction and the second direction are orthogonal in the front view of cover body 70. The first direction and the second direction may not be orthogonal in the front view of cover body 70.

[0061] At least a portion of the surface 72X of the cover portion 72 is covered by the cover body 90. In this embodiment, the entire surface 72X of the cover portion 72 is covered by the cover body 90.

[0062] The joint 80 is formed to allow easy engagement between the current collector 30 of the electrode body 20 and the cover 60. The shape of the joint 80 can be arbitrarily chosen as long as it protrudes from the cover body 70 toward the electrode body 20. In this embodiment, the joint 80 is a plate-shaped part that protrudes from the second surface 71B of the base 71 toward the electrode body 20, i.e., in the first direction.

[0063] The cover body 70 and the joint portion 80 can be made of the same conductive material or different conductive materials. At least one of the cover body 70 and the joint portion 80 can be partially made of different conductive materials. The cover body 70 and the joint portion 80 can be integrally formed or separately formed and joined. When the cover body 70 and the joint portion 80 are integrally formed, the cover body 70 and the joint portion 80 can be manufactured, for example, by machining, grinding, electrical discharge machining, cutting, pressure processing, casting, plastic forming, sintering, 3D printing, or forging. When the cover body 70 and the joint portion 80 are separately formed, the cover body 70 and the joint portion 80 can be joined by welding, interlocking, or riveting. The cover body 70 and the joint portion 80 are not limited to these and can be manufactured by any method.

[0064] The joint 80 has a first end portion 81 and a second end portion 82. The first end portion 81 is one end portion in the FB direction. The first end portion 81 is connected to the lower surface of the base 71. The second end portion 82 is the other end portion in the FB direction. The portion of the joint 80 containing the first end portion 81 is sandwiched between a second cover portion 72B and a third cover portion 72C.

[0065] The junction 80 is joined to the current collector 30 by, for example, ultrasonic bonding. In the manufacturing process of the energy storage device 10, from ensuring that it is used for the mounting device 110 (see reference...) Figure 8 From a spatial perspective, the second end portion 82 of the joint 80 is preferably formed in a position that does not overlap with the cover body 70 in a top view. The second end portion 82 may be formed at a position spaced apart from the outer film 50. When the second end portion 82 is formed at a position spaced apart from the outer film 50, the second end portion 82 is less likely to come into contact with the outer film 50. Therefore, damage to the outer film 50 caused by contact between the joint 80 and the outer film 50 can be suppressed.

[0066] The joint 80 has an upper surface 83 and a lower surface 84. The upper surface 83 is engaged with the current collector 30. The current collector 30 may also be engaged with the lower surface 84. At least the portions of the upper surface 83 and the lower surface 84 that are engaged with the current collector 30 are preferably surface-treated to ensure good engagement with the current collector 30.

[0067] In this embodiment, at least a portion of the lower surface 84 is covered by the cover 90. The lower surface 84 is preferably bonded to the outer film 50 via the cover 90. The area of ​​the lower surface 84 bonded to the outer film 50 can be arbitrarily selected. In this embodiment, a portion of the lower surface 84 is bonded to the outer film 50. The lower surface 84 may also be bonded substantially entirely to the outer film 50. Furthermore, when the cover 60 does not have the cover 90, the cover body 70 and the joint 80 may also be bonded to the outer film 50 by an adhesive.

[0068] The thickness HA of the joint 80 can be arbitrarily selected. To allow adjustment of the position of the second end 82 within the outer casing 40, the joint 80 preferably has a flexible thickness. To prevent damage to the joint 80 even under external force applied to the outer casing 40, the joint 80 preferably has a certain thickness. From this viewpoint, the minimum value of the thickness HA of the joint 80 is preferably, for example, 0.05 mm. The maximum value of the thickness HA of the joint 80 is preferably, for example, 16 mm. The preferred range of the thickness HA of the joint 80 is 0.05 mm to 16 mm. Furthermore, the thickness HA of the joint 80 can vary depending on the location. When the thickness HA of the joint 80 varies depending on the location, the thickness HA of the joint 80 refers to the thickness of the thickest portion.

[0069] like Figure 4 and Figure 5The cover 90 shown has a cover sealing portion 91. The cover sealing portion 91 is heat-sealed to the heat-fusible resin layer 53 of the outer film 50. The cover sealing portion 91 and the outer film 50 can also be joined by any method other than heat sealing, such as welding. Specific welding methods include, for example, laser welding or ultrasonic welding. The cover sealing portion 91 includes a first sealing surface 91A, a second sealing surface 91B, a third sealing surface 91C, and a fourth sealing surface 91D. The first sealing surface 91A forms the upper surface of the cover 60. The first sealing surface 91A is formed on the first covering portion 72A. The first sealing surface 91A extends in a first direction (LR direction in this embodiment) in the front view of the cover 60. The second sealing surface 91B and the third sealing surface 91C are connected to the first sealing surface 91A and form the side surfaces of the cover 60. The second sealing surface 91B is formed on the second covering portion 72B. The third sealing surface 91C is formed on the third covering portion 73C. The second sealing surface 91B and the third sealing surface 91C extend in a second direction (UD direction in this embodiment) intersecting the first direction in the front view of the cover 60. In this embodiment, the first direction and the second direction are orthogonal in the front view of the cover 60. The first direction and the second direction may also not be orthogonal in the front view of the cover 60. The fourth sealing surface 91D forms the lower surface of the cover 60. The fourth sealing surface 91D extends in the first direction (LR direction in this embodiment) in the front view of the cover 60. The fourth sealing surface 91D is formed on the lower surface 84 of the joint 80.

[0070] The cover sealing portion 91 also includes boundaries 92, 93, 94, and 95. Boundary 92 is the boundary between the first sealing surface 91A and the second sealing surface 91B. Boundary 93 is the boundary between the first sealing surface 91A and the third sealing surface 91C. Boundary 94 is the boundary between the fourth sealing surface 91D and the second sealing surface 91B. Boundary 95 is the boundary between the fourth sealing surface 91D and the third sealing surface 91C. The shapes of boundaries 92 to 95 can be angles, or they can be rounded by performing an R-processing. In this embodiment, boundaries 92 to 95 are angles.

[0071] The cover 90 is composed of a resin material. Here, "composed of a resin material" means that when the total material constituting the cover 90 is 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. That is, in addition to the resin material, the material constituting the cover 90 may also contain materials other than the resin material.

[0072] Specific examples of resins include thermoplastic resins such as polyester, polyolefin, polyamide, epoxy resin, acrylic resin, fluoropolymer, polyurethane, silicone resin, and phenolic resin, as well as modified versions of these resins. Additionally, the resin material can be a mixture of these resins, a copolymer, or a modified version of a copolymer. Preferably, the resin material is a thermoplastic resin such as polyester or polyolefin, and more preferably a polyolefin. When the resin material is a resin, the cover 90 can be formed by any molding method.

[0073] The resin material contained in the material constituting the cover 90 is preferably an olefin-based random copolymer, more preferably containing a resin comprising a polyolefin backbone as a main component, more preferably containing a polyolefin as a main component, and even more preferably containing polypropylene as a main component. The polyolefin may also be an acid-modified polyolefin. The resin material contained in the material constituting the cover 90 preferably contains a variety of amide-based lubricants. In addition, the resin material contained in the material constituting the cover 90 preferably contains not only saturated fatty acid amides, but also a variety of amide lubricants and unsaturated fatty acid amides. The resin material contained in the material constituting the cover 90 may also be a polyolefin resin with an added acrylic elastomer having a melting point higher than 150°C.

[0074] Specifically, examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolyesters. Furthermore, examples of copolyesters include copolyesters whose main body is composed of polyethylene terephthalate as a repeating unit. Specifically, examples include copolymer polyesters polymerized with polyethylene isophthalate as the main repeating unit (hereinafter referred to as poly(terephthalic acid / isophthalic acid) glycol ester), poly(terephthalic acid / adipic acid) glycol ester, poly(terephthalic acid / sodium sulfonate isophthalate) glycol ester, poly(terephthalic acid / sodium isophthalate) glycol ester, poly(terephthalic acid / phenyl dicarboxylic acid) glycol ester, and poly(terephthalic acid / sebacic acid) glycol ester. Among these, from the viewpoint of improving heat resistance and pressure resistance, polybutylene terephthalate is preferred as the resin material.

[0075] In addition, examples of polyolefins include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, and other polyethylenes; ethylene-α-olefin copolymers; homopolymer polypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene), propylene-α-olefin copolymers, and terpolymers of ethylene-butene-propylene. Polyolefin resins that are copolymers can be either block copolymers or random copolymers. Among these, polypropylene is preferred from the perspective of excellent heat-melting properties and electrolyte resistance.

[0076] The resin used as the above-mentioned resin material may contain fillers as needed. Specific examples of fillers include glass beads, graphite, glass fiber, and carbon fiber. By containing the above-mentioned fillers in the resin used as the resin material, the deformation resistance of the cover 90 to temperature changes can be improved.

[0077] The melt flow rate of the resin material contained in the material constituting the cover 90 is preferably in the range of 1 g / 10 min to 100 g / 10 min, more preferably in the range of 5 g / 10 min to 80 g / 10 min. The melt flow rate is measured based on JIS K7210-1:2014. The melt flow rate is measured at 230°C.

[0078] In the cover body 60, the cover body 70 may also be made of resin material. When the cover body 70 is made of resin material, the cover 90 may be omitted. When the cover body 70 is made of resin material, it is preferable to attach electrode terminals to the cover body 70. The electrode terminals are attached to the current collector 30.

[0079] The cover 60 can also replace the cover 90 and be bonded to the outer film 50 via an adhesive film. The adhesive film can be any film capable of bonding the outer film 50 to the cover 60. Preferably, the adhesive film is a laminated film having at least a heat-melting resin layer, a heat-resistant substrate layer, and a heat-melting resin layer in sequence. Regarding the specifications of the heat-melting resin layer of the adhesive film, the specifications for the heat-melting resin layer 53 can be applied. The materials constituting the heat-melting resin layers on both sides of the adhesive film can be the same material or different materials, appropriately selected according to the materials of the heat-melting resin layer 53 constituting the outer film 50 and the material constituting the cover 60. The material of the heat-melting resin layer constituting the side bonded to the cover 60 in the adhesive film is preferably an acid-modified polyolefin resin obtained by graft modification with an acid such as maleic anhydride. The heat-melting resin layer on the side of the adhesive film that is bonded to the outer film 50 is preferably made of the same material as the heat-melting resin layer 53 constituting the outer film 50.

[0080] As the heat-resistant substrate layer, any film composed of a heat-resistant resin can be used, such as unstretched or stretched films made of polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polymethylpentene (registered trademark), polyacetal cyclic polyolefins, polyethylene, polypropylene, etc. Among these, polyethylene terephthalate is particularly preferred due to its low cost and high strength.

[0081] The adhesive film preferably has adhesive properties. When the second sealing portion 100B (described later) is formed with the adhesive film disposed between the outer film 50 and the cover 60, the position of the adhesive film relative to the cover 60 and the outer film 50 is not easily shifted. By including an adhesive-imparting resin in the heat-melting resin layer of the adhesive film, adhesiveness can be imparted to the adhesive film. Amorphous polyolefins can be listed as adhesive-imparting resins. Examples of amorphous polyolefins include amorphous polypropylene, or copolymers of amorphous propylene with other α-olefins. The content of the adhesive-imparting resin relative to the base material constituting the heat-melting resin is preferably 10 to 20% by weight or less.

[0082] When the cover 60 is plate-shaped, even when the energy storage devices 10 are arranged in an overlapping configuration, the cover 60 preferably has a certain thickness in order to suppress deformation of the outer casing 40. In another viewpoint, when the cover 60 is plate-shaped, in order to properly heat-seal the cover sealing portion 91 of the cover 60 to the outer casing film 50 during the formation of the second sealing portion 100B (described later), the cover sealing portion 91 of the cover 60 preferably has a certain thickness in the FB direction. The minimum thickness of the cover sealing portion 91 of the cover 60 is, for example, 1.0 mm, more preferably 3.0 mm, and even more preferably 4.0 mm. The maximum thickness of the cover sealing portion 91 of the cover 60 is, for example, 20 mm, more preferably 15 mm, and even more preferably 10 mm. The maximum thickness of the cover sealing portion 91 of the cover 60 can also be 20 mm or more. The preferred range for the thickness of the cap sealing portion 91 constituting the cap body 60 is 1.0mm to 20mm, 1.0mm to 15mm, 1.0mm to 10mm, 3.0mm to 20mm, 3.0mm to 15mm, 3.0mm to 10mm, 4.0mm to 20mm, 4.0mm to 15mm, and 4.0mm to 10mm. In this embodiment, when the cap body 60 is plate-shaped, the cap body 60 does not include a type of material composed solely of a film as specified in the [Packaging Terminology] specifications of JIS (Japanese Industrial Standards). Furthermore, the thickness of the cap sealing portion 91 of the cap body 60 may vary depending on the location of the cap body 60. When the thickness of the cap sealing portion 91 of the cap body 60 varies depending on the location, the thickness of the cap sealing portion 91 is the thickness of the thickest part of the cap body 60.

[0083] In this embodiment, with the outer film 50 wound around the electrode body 20, the first sealing portion 100A is formed by heat-sealing the opposing surfaces (thermofutable resin layer 53) of the outer film 50 to each other.

[0084] The first sealing part 100A passes through Figure 3 The outer film 50 shown is formed by heat sealing a portion including a first edge 50A and a portion including a second edge 50B. A first sealing portion 100A extends along the length of the outer body 40. The location where the first sealing portion 100A is formed within the outer body 40 can be arbitrarily chosen. In this embodiment, the root 70X of the first sealing portion 100A is preferably located on the edge 43 of the boundary between the first surface 41 and the second surface 42 of the outer body 40. The area of ​​the first surface 41 is larger than that of the second surface 42. The root 70X of the first sealing portion 100A can also be located on any surface of the outer body 40. In this embodiment, in the top view, the first sealing portion 100A extends outward from the electrode body 20. The first sealing portion 100A can be folded towards the second surface 42 or towards the first surface 41 of the outer body 40, for example.

[0085] In this embodiment, a second sealing portion 100B (cover sealing portion 100B) is formed by heat-sealing the heat-melt resin layer 53 of the outer film 50 to the cover sealing portion 91 of the cover body 60. Hereinafter, the sealing strength between the heat-melt resin layer 53 of the outer film 50 and the cover sealing portion 91 of the cover body 60 is sometimes referred to as the sealing strength (bonding strength) of the second sealing portion 100B. Furthermore, the sealing strength of the second sealing portion 100B is the long side portion of the cover sealing portion 91, i.e. Figure 1A The sealing strength between the heat-fused resin layer 53 at the cover sealing portion 91 extending in the LR (width) direction and the cover body 60.

[0086] The sealing strength of the second sealing part 100B is measured as follows. First, a cut is formed in the portion of the outer membrane 50 that constitutes the first surface 41 of the outer body 40, forming three strip-shaped parts 41X, 41Y, and 41Z arranged in the LR direction (see reference). Figure 1B(The double-dotted line). The width of the three strip components 41X, 41Y, and 41Z in the LR direction is 15mm. The ends of the strip components 41X, 41Y, and 41Z are engaged with the cover body 60 in the second sealing part 100B. The length of the cover body 60 in the LR direction is 45mm or more. Next, by pulling the ends of the strip components 41X, 41Y, and 41Z opposite to the ends engaged with the cover body 60 upward in the UD direction (opposite to the first surface 41B), the sealing strength of the strip components 41X, 41Y, and 41Z is measured respectively. The distance between the clips in the UD direction is 10mm. The sealing strength of the strip components 41X, 41Y, and 41Z is the peak value of each sealing strength. In this embodiment, the sealing strength of the second sealing part 100B is the average value of the sealing strength of the strip components 41X, 41Y, and 41Z. When the length of the cover 60 in the LR direction is less than 45 mm, three strip-shaped components with an arbitrary width of less than 15 mm (X mm) are formed. The sealing strength of the three strip-shaped components is measured using the same method as when the length of the cover 60 in the LR direction is 45 mm or more. The obtained sealing strength is divided by the arbitrary width (X mm) and then multiplied by 15 to convert it into the sealing strength of the three strip-shaped components with a width of 15 mm. The sealing strength of the second sealing part 100B is the average of the sealing strengths of the three strip-shaped components converted to a width of 15 mm. In addition, when the cover 60 is divided into multiple parts including long and short sides, the sealing strength of the second sealing part 100B is the sealing strength of the long side portion of the multiple cover sealing parts 91.

[0087] From the viewpoint of effectively maintaining the state of the electrode body 20 sealed by the outer casing 40, the sealing strength of the second sealing portion 100B is preferably 40 N / 15 mm or more, more preferably 50 N / 15 mm or more, even more preferably 60 N / 15 mm or more, even more preferably 70 N / 15 mm or more, and still more preferably 85 N / 15 mm or more. When the sealing strength of the second sealing portion 100B is 40 N / 15 mm or more, even if the energy storage device 10 is used for, for example, several years (less than 10 years), the state of the electrode body 20 being sealed by the outer casing 40 can be effectively maintained. When the sealing strength of the second sealing portion 100B is 85 N / 15 mm or more, even if the energy storage device 10 is used for, for example, 10 years or more, the state of the electrode body 20 being sealed by the outer casing 40 can be effectively maintained. The sealing strength of the second sealing portion 100B is preferably 300 N / 15 mm or less. The preferred range of sealing strength for the second sealing part 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.

[0088] In this embodiment, to prevent gaps from forming between the outer film 50 and the cover 60, the cover 60 preferably has a protrusion 96 protruding from the cover sealing portion 91. The protrusion 96 can be integrally formed with the cover 90, or it can be separately formed from and joined to the cover 90. In this embodiment, the protrusion 96 is integrally formed with the cover 90. The location of the protrusion 96 in the cover sealing portion 91 can be arbitrarily chosen. Gaps between the outer film 50 and the cover 60 can easily form, for example, between the root 100AX of the first sealing portion 100A and the cover 60. In particular, when the root 100AX of the first sealing portion 100A is located at the boundary 92 to boundary 95 of the cover 60, the resin filling between the root 100AX of the first sealing portion 100A and the cover 60 is easily reduced. Therefore, the protrusion 96 is preferably formed in the cover sealing portion 91 at the location of the root 100AX of the first sealing portion 100A. In this embodiment, the root 100AX of the first sealing portion 100A is located at the boundary 92 of the cover 60. Therefore, the protrusion 96 is preferably formed at the boundary 92 in the cover sealing portion 91. In this embodiment, the first sealing portion 100A is sealed with the protrusion 96 sandwiched between it. Furthermore, the protrusion 96 may also be formed in at least one of the first sealing surface 91A, the second sealing surface 91B, the third sealing surface 91C, the fourth sealing surface 91D, the boundary 93, the boundary 94, and the boundary 95.

[0089] The shape of the protrusion 96 can be arbitrarily chosen. In this embodiment, the protrusion 96 is plate-shaped. The thickness of the protrusion 96 can be arbitrarily chosen. In this embodiment, the protrusion 96 becomes thinner as it moves away from the boundary 92. In other words, the protrusion 96 tapers at its front end as it moves away from the boundary 92. The thickness of the protrusion 96 can be a fixed value, or it can become thicker as it moves away from the boundary 92.

[0090] The direction in which the protrusion 96 extends can be arbitrarily chosen. In this embodiment, the protrusion 96 extends in a first direction (LR direction in this embodiment). The protrusion 96 may also extend in a second direction (UD direction in this embodiment). In the front view of the cover 60, the protrusion 96 may also extend upward in a third direction that intersects the first direction (LR direction in this embodiment) and the second direction (UD direction in this embodiment).

[0091] The length of the protrusion 96 can be arbitrarily selected within a range less than or equal to the length of the first sealing portion 100A. For example, the length of the protrusion 96 can be substantially equal to the length of the first sealing portion 100A, or it can be 30% to 50% of the length of the first sealing portion 100A.

[0092] <1-2. Manufacturing Methods of Energy Storage Devices>

[0093] Figure 7 This is a flowchart illustrating 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 one through five are performed, for example, by a manufacturing apparatus for the energy storage device 10. At least some of steps one through five can also be performed by an operator. Furthermore, steps one through five are names of each step in the manufacturing method of the energy storage device 10 for convenience and do not necessarily imply the order of the steps. The order of steps one through five can be arbitrarily changed as long as it is not technically contradictory.

[0094] In the first step of step S11, the manufacturing apparatus arranges a pair of cover bodies 60 on the side of the electrode body 20 in the FB direction.

[0095] The second step of step S12 is performed after the first step. In the second step, the manufacturing apparatus joins the current collector 30 and the cover 60 at the joint 80. Alternatively, when the cover body 70 and the joint 80 are separately constructed, the joint 80 and the cover body 70 may be joined after the current collector 30 and the joint 80 are joined.

[0096] Figure 8 This diagram pertains to the second process. In this embodiment, in the second process, the current collector 30 and the junction 80 are joined by ultrasonic welding. The current collector 30 and the junction 80 can also be joined by resistance welding or laser welding. Ultrasonic welding is performed using apparatus 110. Apparatus 110 is a known ultrasonic device, comprising a head 111, an anvil 112, an amplitude transformer 113, and an oscillator 114. In the second process, the current collector 30 and the junction 80 are ultrasonically joined while the upper surface 83, lower surface 84, and portion containing the end 31 of the current collector 30 are clamped by the head 111 and the anvil 112.

[0097] The third step, S13, is performed after the second step. In the third step, the manufacturing apparatus, while restricting the movement of the electrode body 20 and the cover 60 using a limiting member, winds the outer film 50 around the electrode body 20 and the cover 60 under tension. The limiting member is, for example, a groove for fitting the electrode body 20 and the cover 60. The limiting member can also be a device that applies external force to the electrode body 20 and the cover 60 to prevent movement of the electrode body 20 and the cover 60. The limiting member can also be a device that applies a force to the electrode body 20 and the cover 60 in the opposite direction to the direction of pulling the outer film 50. In addition, to eliminate wrinkles in the outer film 50, the limiting member can include a roller that travels on the outer film 50 while it is being pulled. Alternatively, the electrode body 20 can be housed inside the cylindrical outer film 50, which has openings at both ends in the FB direction, and the openings can be closed with the cover 60 after the current collector 30 and the joining portion 80 are joined. In another example, the electrode body 20, which is connected to the joint 80 of the cover 60, can also be housed inside the outer casing 50, which is configured as a cylindrical outer casing with openings at both ends in the FB direction, and the openings can be closed with the cover 60.

[0098] The fourth step, S14, is performed after the third step. In the fourth step, the manufacturing apparatus forms the second sealing part 110B by heat-sealing the outer film 50 to the cover 60.

[0099] The fifth step of step S15 is performed before or after the fourth step. In the fifth step, the manufacturing apparatus forms a first sealing portion 100A by heat-sealing the heat-melting resin layer 53 including the portion of the first edge 50A and the heat-melting resin layer 53 including the portion of the second edge 50B of the outer film 50 while applying tension to the outer film 50 while restricting the movement of the electrode body 20 and the cover body 60.

[0100] <1-3. Functions and Effects of Energy Storage Devices>

[0101] According to the energy storage device 10, since it has a connecting portion 80, the space for the device 110 for arranging the connecting current collector 30 and the cover 60 can be easily ensured during the manufacturing process of the energy storage device 10. Therefore, the current collector 30 and the cover 60 can be connected well.

[0102] [2. Variations]

[0103] The above embodiments illustrate possible ways of manufacturing the energy storage device, cover, and method of manufacturing the energy storage device of the present invention, and are not intended to limit the scope of the embodiments. The energy storage device, cover, and method of manufacturing the energy storage device of the present invention can be carried out in ways different from those illustrated in the embodiments. One example is the substitution, modification, or omission of a part of the structure of the embodiment, or the addition of a new structure to the embodiment. Several examples of variations of the embodiments are shown below. Furthermore, the following variations can be combined with each other as long as they are not technically contradictory.

[0104] <2-1. First Variation>

[0105] In the above embodiment, the position of the forming joint 80 of the cover 60 can be changed arbitrarily. Figure 9 This is a perspective view of the cover 160 of the energy storage device 10 in the first modified example. The cover 160 has a joint 180. The first end 81 of the joint 180 is at least connected to the cover body 70. Figure 9 In the example shown, the cover 72 preferably has a fourth cover 72D. The fourth cover 72D forms the lower surface of the cover body 70. The fourth cover 72D is connected to the second cover 72B and the third cover 72C. The fourth cover 72D extends in a first direction (LR direction in this embodiment) in the front view of the cover body 160. When the cover 72 has the fourth cover 72D, the lower surface 84 of the joint 180 does not need to be covered by the cover 90, so the second end 82 can be formed at a position spaced apart from the outer film 50. When the second end 82 is formed at a position spaced apart from the outer film 50, the second end 82 is less likely to come into contact with the outer film 50. Therefore, damage to the outer film 50 caused by contact between the joint 80 and the outer film 50 can be suppressed.

[0106] <2-2. Second Variation>

[0107] In the above embodiments, the shape of the joint 80 can be changed arbitrarily. Figure 10 This is a cross-sectional view of the energy storage device 10 of the second modification. The energy storage device 10 of the second modification includes a cover 260. The cover 260 has a joint 280. The joint 280 has a first portion 281 and a second portion 282. The first portion 281 is connected to the cover body 70 and extends in a first direction toward the electrode body 20. Figure 10 In the example shown, the first direction is the FB direction. The second part 282 is connected to the first part 281 and extends in a second direction intersecting the first direction in the side view of the cover 60. Figure 10 In the example shown, the second direction is the UD direction. The angle between the first and second directions is within the range of greater than 0° and less than 180°. Figure 10In the example shown, the angle between the first direction and the second direction is 90°. In the second variation, the second portion 282 of the joint 280 is joined to the current collector 30.

[0108] The first part 281 and the second part 282 can be integrally formed or separately formed and joined. In a second variation, the first part 281 and the second part 282 are integrally formed. More specifically, in the second variation, the first part 281 and the second part 282 are formed by bending a joint 280. In the second variation, since the joint 280 has a thickness that allows it to be bent, it is flexible. Therefore, even if external forces such as vibration are applied to the energy storage device 10, the joint 280 is not easily damaged. In other words, the joint 280 has high durability. In addition, since the joint 280 extends in the second direction, it is possible to reduce the size of the energy storage device 10 in the FB direction compared to a structure in which the joint extends entirely in the first direction. Furthermore, since the second end 82 is formed at a position spaced apart from the outer film 50, the second end 82 is less likely to come into contact with the outer film 50. Therefore, damage to the outer film 50 caused by contact between the joint 280 and the outer film 50 can be suppressed.

[0109] <2-3. Third Variation>

[0110] Figure 11 This is a cross-sectional view of the energy storage device 10, which is a third modification of the second modification. The energy storage device 10 of the third modification includes a cover 360. The cover 360 has a joint 380. In addition to the first portion 281 and the second portion 282 of the second modification, the joint 380 also has a third portion 383. The third portion 383 is connected to the second portion 282 and extends in a first direction toward the electrode body 20. Figure 11 In the example shown, the first direction is the FB direction. The first part 281, the second part 282, and the third part 383 can be integrally formed, or they can be formed as at least two separate parts joined together. In the third variation, the first part 281, the second part 282, and the third part 383 are integrally formed. More specifically, in the third variation, the first part 281, the second part 282, and the third part 383 are formed by bending a joint 380. The energy storage device 10 of the third variation also achieves the same effect as the energy storage device 10 of the second variation.

[0111] <2-4. Fourth Variation>

[0112] In the above embodiment, the covering portion 72 may be omitted from the cover body 70. In a fourth variation, the side (edge) of the base 71 may be covered by the covering body 90. In a fourth variation, the first end portion 81 of the joint portion 80 may be connected to the second surface 71B of the base 71 or to the side of the base 71.

[0113] <2-5. Fifth Variation>

[0114] In the above embodiment, the outer casing 50 of the energy storage device 10 can extend outward in the FB direction beyond at least one of the two covers 60. The electrode body 20 is encapsulated by closing the portion of the outer casing 50 that extends outward beyond the cover 60. The portion of the outer casing 50 that extends outward beyond the cover 60 can be folded like a gable top bag or a brick pack. In a fifth variation, it is preferable to attach the electrode terminals to the second surface 71B of the cover 60. The length of the electrode terminals in the FB direction is preferably a length that allows them to be exposed from the portion of the outer casing 50 that extends outward beyond the cover 60.

[0115] <2-6. Sixth Variation>

[0116] In the above embodiment, the outer casing 40 may also omit one of the two covers 60. In this variation, in the FB direction, the portion of the outer casing 40 without the cover 60 is encapsulated by sealing the portion of the electrode body 20 extending outward in the outer casing film 50. The portion of the electrode body 20 extending outward in the outer casing film 50 can be folded like a herringbone-shaped bag or a brick-shaped bag.

[0117] <2-7. Seventh Variation>

[0118] In the above embodiments, the outer shape of the outer body 40 can be arbitrarily changed. The outer shape of the outer body 40 can be a cylinder, a prism, or a cube.

[0119] Explanation of reference numerals in the attached figures

[0120] 10: Energy storage devices

[0121] 20: Electrode body

[0122] 30: Current collector

[0123] 40: Exterior body

[0124] 50: Exterior film

[0125] 60, 260, 360: Cover

[0126] 70: Cover body

[0127] 80, 280, 380: Joints

[0128] 81, 181: First end

[0129] 82, 182: Second end

[0130] 281: Part One

[0131] 282: Part Two.

Claims

1. An energy storage device, characterized in that, include: An electrode body containing a current collector; The outer film covering the electrode body; and A cover, made of conductive material, that seals the electrode body together with the outer membrane. The cover has: Cover the main body; and A joint portion that protrudes from the cover body toward the electrode body and engages with the current collector.

2. The energy storage device as described in claim 1, characterized in that: The cover body is joined to the outer membrane.

3. The energy storage device as described in claim 1 or 2, characterized in that: The end of the joint opposite to the cover body is spaced apart from the outer film.

4. The energy storage device as described in claim 1 or 2, characterized in that: The joint has: A first portion connected to the cover body and extending in a first direction toward the electrode body; and A second portion connected to the first portion, which extends in a second direction intersecting the first direction when viewed from the side of the cover.

5. A cover that can be used as an outer casing for an energy storage device, characterized in that, include: Cover the main body; and A joint protruding from the cover body, capable of connecting to the current collector of the energy storage device.

6. The cover as described in claim 5, characterized in that: The joint has: A first portion connected to the cover body and extending in a first direction toward the electrode body of the energy storage device; and A second portion connected to the first portion, which extends in a second direction intersecting the first direction when viewed from the side of the cover.

7. A method for manufacturing an energy storage device, characterized in that: The energy storage device includes: An electrode body containing a current collector; The outer film covering the electrode body; and A cover, made of conductive material, that seals the electrode body together with the outer membrane. The cover has: Cover the main body; and A joint portion that protrudes from the cover body toward the electrode body and engages with the current collector. The method for manufacturing the energy storage device includes a step of joining the junction and the current collector.

Images