Energy storage device, lid, method for manufacturing an energy storage device

Abstract

To provide a power storage device, a lid, and a manufacturing method of the power storage device in which an electrode body is suitably maintained in a sealed state by an exterior body.SOLUTION: A power storage device 10 includes an electrode body 20 and an exterior body 40 that seals the electrode body 20, and the exterior body 40 includes an exterior film 50 wrapped around the electrode body 20 so as to have an opening, a lid 60 disposed in the opening, a first sealing portion 70 in which surfaces of the exterior film 40 that face each other are sealed, and a second sealing portion 80 in which opposing surfaces of the lid 60 and the exterior film 40 are sealed, and the sealing strength of the second sealing portion 80 is 40 N / 15 mm or more.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses an all-solid-state battery as an example of a power storage device. This all-solid-state battery includes an electrode body and an exterior body that seals the electrode body. The exterior body includes an exterior film wound around the electrode body so as to have an opening, and a lid body disposed at the opening. The outer peripheral surfaces of the exterior film and the lid body are heat-sealed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a power storage device, in order to maintain the state in which the electrode body is sealed by the exterior body, it is preferable that the exterior film and the lid body are firmly joined. In the above all-solid-state battery, there is room for improvement in that regard.

[0005] An object of the present invention is to provide a power storage device in which the state in which the electrode body is sealed by the exterior body is suitably maintained, a lid body used for this power storage device, and a method for manufacturing a power storage device.

Means for Solving the Problems

[0006] A first aspect of the present invention relates to an energy storage device comprising an electrode body and an outer casing for sealing the electrode body, wherein the outer casing includes an outer film wrapped around the electrode body so as to have an opening, a lid positioned in the opening, a first sealing portion where opposing surfaces of the outer film are sealed together, and a second sealing portion where opposing surfaces of the lid and the outer film are sealed together, the sealing strength of the second sealing portion being 40 N / 15 mm or more.

[0007] A second 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 includes an outer film wrapped around the electrode body so as to have an opening, a lid positioned in the opening, a first sealing portion where opposing surfaces of the outer casing film are sealed together, and a second sealing portion where opposing surfaces of the lid and the outer casing film are sealed together, wherein the lid includes a first surface on the electrode body side and a second surface opposite to the first surface, an inner poly reservoir is formed between the first surface and the outer casing film, and an outer poly reservoir is formed between the second surface and the outer casing film, the length of the inner poly reservoir being shorter than the length of the outer poly reservoir.

[0008] A third 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 includes an outer film wrapped around the electrode body so as to have an opening, a lid positioned in the opening, a first sealing portion where opposing surfaces of the outer casing film are sealed together, and a second sealing portion where opposing surfaces of the lid and the outer casing film are sealed together, wherein the outer casing film has a lid-wrapping portion in the second sealing portion that is sealed with the lid, the lid has a lid-sealing surface in the second sealing portion that is sealed with the outer casing film, and the ratio of the length of the lid-wrapping portion to the length of the lid-sealing surface is 103% or less.

[0009] A fourth aspect of the present invention relates to a power storage device according to the first or third aspect, wherein the lid includes a first surface on the electrode side and a second surface opposite to the first surface, an inner poly reservoir is formed between the first surface and the outer film, an outer poly reservoir is formed between the second surface and the outer film, the outer film includes a heat-sealable resin layer that seals to the lid, and the ratio of the thickness of the inner poly reservoir to the thickness of the heat-sealable resin layer is 200% or less.

[0010] A fifth aspect of the present invention relates to a power storage device according to the third aspect, wherein the sealing strength of the second sealing portion is 40 N / 15 mm or more.

[0011] A power storage device according to the sixth aspect of the present invention is a power storage device according to any one of the first to fifth aspects, wherein the outer film includes a heat-sealable resin layer that is sealed to the lid, and the main material of the material constituting the heat-sealable resin layer and the material constituting the lid are the same.

[0012] A power storage device according to a seventh aspect of the present invention is a power storage device according to a third aspect, wherein the cover includes a first surface on the electrode body side and a second surface opposite to the first surface, an inner poly reservoir is formed between the first surface and the outer film, an outer poly reservoir is formed between the second surface and the outer film, and the length of the inner poly reservoir is shorter than the length of the outer poly reservoir.

[0013] An energy storage device according to the eighth aspect of the present invention is an energy storage device according to the third aspect, wherein the lid includes a first surface on the electrode body side and a second surface opposite to the first surface, an inner poly reservoir is formed between the first surface and the outer film, an outer poly reservoir is formed between the second surface and the outer film, the outer film includes a heat-sealable resin layer that seals to the lid, and the ratio of the thickness of the inner poly reservoir to the thickness of the heat-sealable resin layer is 200% or less.

[0014] A lid according to a ninth aspect of the present invention is a lid used for the exterior of an energy storage device, wherein the exterior includes an exterior film wrapped around an electrode body so as to have an opening, and the lid includes a sealing surface positioned in the opening and sealed with the exterior film, the sealing surface having a recess.

[0015] A cover according to a tenth aspect of the present invention is a cover used for the exterior of an energy storage device, wherein the exterior includes an exterior film wrapped around an electrode body so as to have an opening, and the cover includes a sealing surface disposed in the opening and sealed with the exterior film, the sealing surface having a groove.

[0016] A lid according to an eleventh aspect of the present invention is a lid used for an outer casing of an energy storage device, wherein the outer casing includes an outer film wrapped around an electrode body so as to have an opening, the lid includes a first surface on the electrode body side, a second surface opposite to the first surface, and a sealing surface that connects the first surface and the second surface and seals with the outer casing film, the sealing surface includes an inclined surface that slopes toward the center of the lid in the height direction as it moves from the second surface toward the first surface.

[0017] A power storage device according to the twelfth aspect of the present invention is a power storage device comprising a lid as described in any one of the ninth to eleventh aspects, comprising an electrode body and an outer casing for sealing the electrode body, wherein the outer casing includes an outer film wrapped around the electrode body so as to have an opening, the lid disposed in the opening, a first sealing portion where the opposing surfaces of the outer film are sealed together, and a second sealing portion where the opposing surfaces of the lid and the outer film are sealed together.

[0018] A method for manufacturing an energy storage device according to a thirteenth aspect of the present invention is a method for manufacturing an energy storage device comprising an electrode body and an outer casing for sealing the electrode body, wherein the outer casing includes an outer film wrapped around the electrode body so as to have an opening, a lid disposed in the opening, a first sealing portion in which opposing surfaces of the outer casing film are sealed together, and a second sealing portion in which opposing surfaces of the lid and the outer casing film are sealed together, wherein the lid includes a first surface on the electrode body side and a second surface opposite to the first surface, and the method for manufacturing the energy storage device includes a sealing step of forming the second sealing portion using a sealing bar, wherein the sealing bar is tilted so as to be closer to the boundary between the first surface and the outer casing film than to the boundary between the second surface and the outer casing film.

[0019] A method for manufacturing an energy storage device according to a fourteenth aspect of the present invention is a method for manufacturing an energy storage device comprising an electrode body and an outer casing for sealing the electrode body, wherein the outer casing includes an outer film wrapped around the electrode body so as to have an opening, a lid disposed in the opening, a first sealing portion where opposing surfaces of the outer casing film are sealed together, and a second sealing portion where opposing surfaces of the lid and the outer casing film are sealed together, wherein the lid includes a first surface on the electrode body side and a second surface opposite to the first surface, and the method for manufacturing the energy storage device includes a sealing step of forming the second sealing portion using a sealing bar, wherein the sealing temperature of the portion including the boundary between the first surface and the outer casing film is lower than the sealing temperature of the portion including the boundary between the second surface and the outer casing film. [Effects of the Invention]

[0020] According to the present invention, the energy storage device, the cover, and the method for manufacturing the energy storage device, the state in which the electrode body is sealed by the outer casing is suitably maintained. [Brief explanation of the drawing]

[0021] [Figure 1] A perspective view of the energy storage device according to the first embodiment. [Figure 2]Cross-sectional view showing the layer structure of the exterior film included in the power storage device of FIG. 1. [Figure 3] View of the exterior film included in the power storage device of FIG. 1 in a spread-out state. [Figure 4] Front view of the lid included in the power storage device of FIG. 1. [Figure 5] Side view of the lid of FIG. 4. [Figure 6] Flowchart showing an example of the manufacturing process of the power storage device of FIG. 1. [Figure 7] Cross-sectional view of the power storage device of the second embodiment viewed from the side of the second sealing portion. [Figure 8] Cross-sectional view of the power storage device of FIG. 7 viewed from the electrode body side. [Figure 9] View of the power storage device of FIG. 7 viewed from the side opposite to the electrode body. [Figure 10] Perspective view showing an example of the lid included in the power storage device of FIG. 7. [Figure 11] Perspective view showing another example of the lid included in the power storage device of FIG. 7. [Figure 12] Perspective view showing yet another example of the lid included in the power storage device of FIG. 7. [Figure 13] Cross-sectional view showing an example of the sealing process of the manufacturing method of the power storage device of FIG. 7. [Figure 14] Side view of the lid included in the power storage device of a modified example of the first embodiment. [Figure 15] Front view of the lid included in the power storage device of another modified example of the first embodiment. [Figure 16] Side view of the lid included in the power storage device of a modified example of the second embodiment. [Figure 17] Side view of the lid included in the power storage device of another modified example of the second embodiment. [Figure 18] Cross-sectional view of the power storage device of another modified example of the second embodiment viewed from the side of the second sealing portion. [Figure 19] Front view of the lid with the adhesive film of FIG. 18 adhered thereto. [Figure 20] Table showing the test results of the first test. [Figure 21] Table showing the test results of the second test. [Modes for carrying out the invention]

[0022] A device for storing energy according to one embodiment of the present invention will be described below with reference to the drawings. In this specification, the numerical range indicated by "~" means "greater than or equal to" and "less than or equal to". For example, the notation 2~15mm means 2mm or more and 15mm or less.

[0023] [1. First Embodiment] <1-1. Configuration of Energy Storage Devices> Figure 1 is a schematic plan view of the energy storage device 10 of the first embodiment. Figure 2 is a cross-sectional view showing the layer structure of the outer film 50 of the energy storage device 10 in Figure 1. Figure 3 is a view of the outer film 50 of the energy storage device 10 in Figure 1 in an unfolded state. Figure 4 is a front view of the lid 60 of the energy storage device 10 in Figure 1. Figure 5 is a side view of the lid 60 of Figure 4. In Figure 1, the arrow UD indicates the thickness direction of the energy storage device 10, the arrow LR indicates the width direction of the energy storage device 10, and the arrow FB indicates the depth direction of the energy storage device 10.

[0024] The energy storage device 10 comprises an electrode body 20, electrode terminals 30, and an outer casing 40. The electrode body 20 includes electrodes (positive and negative electrodes) that constitute an energy storage component such as a lithium-ion battery, capacitor, all-solid-state battery, semi-solid-state battery, pseudo-solid-state battery, polymer battery, all-resin battery, lead-acid battery, nickel-metal hydride battery, nickel-cadmium battery, nickel-iron battery, nickel-zinc battery, silver oxide-zinc battery, metal-air battery, polyvalent cation battery, or capacitor, as well as a separator. In this embodiment, the shape of the electrode body 20 is substantially rectangular parallelepiped. Note that "substantially rectangular parallelepiped" includes not only a perfect rectangular parallelepiped but also a solid that can be considered a rectangular parallelepiped by modifying the shape of a part of its outer surface, for example. The shape of the electrode body 20 may be, for example, a cylinder or a polygonal prism.

[0025] In this embodiment, the energy storage device 10 is equipped with two electrode terminals 30. The electrode terminals 30 are metal terminals used for inputting and outputting power to the electrode body 20. One end of the electrode terminal 30 is electrically connected to an electrode (positive or negative electrode) included in the electrode body 20. The other end of the electrode terminal 30 protrudes outward from, for example, the edge of the outer casing 40. Note that the electrode terminals 30 only need to be able to input and output power to the electrode body 20, and do not need to protrude from, for example, the outer casing 40. If the cover 60, which will be described later, is made of metal, for example, the cover 60 may also function as an electrode terminal 30, and in this case, the cover 60 that functions as an electrode terminal may or may not protrude from the outer casing 40.

[0026] The metal material constituting the electrode terminal 30 is, for example, aluminum, nickel, or copper. For example, if the electrode body 20 is a lithium-ion battery, the electrode terminal 30 connected to the positive electrode is usually made of aluminum, and the electrode terminal 30 connected to the negative electrode is usually made of copper, nickel, or the like. The outermost layer of the electrode body 20 does not necessarily have to be an electrode; for example, it may be a protective tape or a separator.

[0027] The outer casing 40 seals the electrode body 20. The outer casing 40 comprises an outer film 50 and a lid 60. The outer film 50 is wrapped around the electrode body 20 so as to have an opening 40A, and the lid 60 is positioned to the side of the electrode body 20 to close the opening 40A.

[0028] 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.

[0029] The outer film 50 is, for example, a laminate (laminate film) having a base layer 51, a barrier layer 52, and a heat-sealable resin layer 53 in that order. However, the outer film 50 does not necessarily need to contain 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. Preferably, the outer film 50 is heat-sealable.

[0030] 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 20 to 150 μm, from the viewpoint of film strength.

[0031] The barrier layer 52 is joined to the base material layer 51, for example, via an adhesive layer 54. The barrier layer 52 included in the outer film 50 is made of, for example, aluminum foil, from the viewpoint of processability such as moisture resistance and ductility, and cost. The aluminum foil preferably contains iron from the viewpoint of packaging suitability and pinhole resistance when packaging the electrode body 20. The iron content in the aluminum foil is preferably 0.5 to 5.0 mass%, and more preferably 0.7 to 2.0 mass%. An iron content of 0.5 mass% or more provides packaging suitability, excellent pinhole resistance, and ductility of the outer film 50. An iron content of 5.0 mass% or less provides excellent flexibility of the outer film 50. The barrier layer 52 may also include a metal foil, a vapor-deposited film, and a resin layer that have barrier properties. Examples of metal foils include aluminum alloy, stainless steel, titanium steel, or steel plate.

[0032] The thickness of the barrier layer 52 is preferably 15 to 100 μm, and more preferably 30 to 80 μm, from the viewpoint of barrier properties, pinhole resistance, and packaging suitability. A barrier layer thickness of 15 μm or more makes the outer film 50 less likely to break even when stress is applied during packaging. A barrier layer thickness of 100 μm or less reduces the mass increase of the outer film 50, thereby suppressing a decrease in the gravimetric energy density of the energy storage device 10.

[0033] Furthermore, if the barrier layer 52 is aluminum foil, it is preferable to provide a corrosion-resistant coating on at least the side opposite to the base layer 51 to prevent dissolution and corrosion. The barrier layer 52 may have a corrosion-resistant coating on both sides. Here, a corrosion-resistant coating refers to a thin film that provides corrosion resistance (e.g., acid resistance, alkali resistance, etc.) to the barrier layer 52 by performing corrosion prevention treatments on the surface of the barrier layer 52, such as hot water modification treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or coating agent application. Specifically, a corrosion-resistant coating means a coating that improves the acid resistance of the barrier layer 52 (acid-resistant coating), a coating that improves the alkali resistance of the barrier layer 52 (alkali-resistant coating), etc. One type of treatment may be performed to form the corrosion-resistant coating, or two or more types may be combined. In addition, it is possible to have multiple layers instead of just one layer. Furthermore, among these treatments, hydrothermal modification and anodic oxidation are processes that dissolve the surface of the metal foil with a treatment agent to form a metal compound with excellent corrosion resistance. These treatments may also be included in the definition of chemical conversion treatment. Additionally, if the barrier layer 52 has a corrosion-resistant coating, the barrier layer 52 includes the corrosion-resistant coating.

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

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

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

[0037] The materials constituting the buffer layer can be arbitrarily selected from materials having cushioning properties. Examples of cushioning materials include rubber, nonwoven fabric, or foamed sheet. Examples of rubber include natural rubber, fluororubber, or silicone rubber. The rubber hardness is preferably around 20 to 90. The materials constituting the nonwoven fabric are preferably materials with excellent heat resistance. When the buffer layer is made of nonwoven fabric, the lower limit of the buffer layer thickness is preferably 100 μm, more preferably 200 μm, and still more preferably 1000 μm. When the buffer layer is made of nonwoven fabric, the upper limit of the buffer layer thickness is preferably 5000 μm, and still more preferably 3000 μm. The preferred thickness ranges for the buffer layer are 100 μm to 5000 μm, 100 μm to 3000 μm, 200 μm to 5000 μm, 200 μm to 3000 μm, 1000 μm to 5000 μm, or 1000 μm to 3000 μm. Among these, the most preferred thickness range for the buffer layer is 1000 μm to 3000 μm.

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

[0039] If the outer film 50 has a buffer layer, the buffer layer functions as a cushion, thus preventing damage to the outer film 50 from impact when the energy storage device 10 is dropped or from handling during the manufacturing of the energy storage device 10.

[0040] The lid 60 is, for example, rectangular in shape and is made of, for example, a resin material. The lid 60 may be formed by, for example, cold forming of the outer film 50, or it may be a metal molded product. The lid 60 has a first surface 61, a second surface 62, a third surface 63, a fourth surface 64, a fifth surface 65, and a sixth surface 66. The first surface 61 faces the electrode body 20. The second surface 62 is the surface opposite to the first surface 61. The third surface 63 constitutes the top surface of the lid 60. The fourth surface 64 constitutes the bottom surface of the lid 60. The fifth surface 65 and the sixth surface 66 constitute the sides of the lid 60. The third surface 63, the fourth surface 64, the fifth surface 65, and the sixth surface 66 are lid sealing surfaces that are heat-sealed to the heat-sealable resin layer 53 of the outer film 50. In the following, surfaces 3 through 66 may be collectively referred to as the lid sealing surface 67.

[0041] From the viewpoint of suitably heat-sealing the lid 60 and the outer film 50, it is preferable that the main material of the material constituting the lid 60 and the material constituting the heat-sealable resin layer 53 of the outer film 50 are the same. In this embodiment, the main material of the material constituting the lid 60 and the material constituting the heat-sealable resin layer 53 is polypropylene. The main material refers to, for example, a material that accounts for 50% or more of the materials included in the constituent elements.

[0042] In this embodiment, the lid 60 has a through hole 60X into which the electrode terminal 30 is inserted. The through hole 60X penetrates the first surface 61 and the second surface 62. With the electrode body 20 housed inside, the electrode terminal 30 protrudes to the outside of the outer casing 40 through the through hole 60X formed in the lid 60. The small gap between the through hole 60X in the lid 60 and the electrode terminal 30 is filled with, for example, resin. In the energy storage device 10, the position in which the electrode terminal 30 protrudes to the outside can be arbitrarily selected. For example, the electrode terminal 30 may protrude to the outside through a hole formed in any of the six surfaces of the outer casing 40. In this case, the small gap between the outer casing 40 and the electrode terminal 30 is filled with, for example, resin. In the energy storage device 10, the lid 60 and the electrode terminal 30 are provided as separate parts, but the lid 60 and the electrode terminal 30 may be formed integrally. Furthermore, if the electrode terminals 30 do not protrude from the edge of the outer casing 40, the lid 60 does not need to have a through hole 60X.

[0043] In this embodiment, the outer film 50 is wrapped around the electrode body 20 so as to have an opening 40A, and the first sealing portion 70 is formed by heat sealing the opposing surfaces (heat-fusible resin layers 53) of the outer film 50 together.

[0044] The first sealing portion 70 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 70 extends in the longitudinal direction of the outer body 40. The position in the outer body 40 where the first sealing portion 70 is formed can be arbitrarily selected. In this embodiment, the base 70X of the first sealing portion 70 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 70X of the first sealing portion 70 may be located on any surface of the outer body 40. In this embodiment, the first sealing portion 70 is folded toward the second surface 42 of the outer body 40, for example. In a plan view, the first sealing portion 70 may protrude outward from the electrode body 20, or it may be folded toward the first surface 41.

[0045] In this embodiment, a second sealing portion 80 is formed by heat sealing the heat-fusible resin layer 53 of the outer film 50 and the lid sealing surface 67 of the lid 60. Hereinafter, the sealing strength between the heat-fusible resin layer 53 of the outer film 50 and the lid sealing surface 67 of the lid 60 may be referred to as the sealing strength of the second sealing portion 80. The sealing strength of the second sealing portion 80 is the sealing strength between the heat-fusible resin layer 53 and the lid 60 on the long side portion of the lid sealing surface 67, that is, the portion of the lid sealing surface 67 extending in the LR (width) direction in Figure 1. The sealing strength of the second sealing portion 80 is measured by pulling the outer film 50 relative to the lid 60 in the UD (up and down) direction in Figure 1 and measuring the distance of the second sealing portion 80 in the FB (depth) direction. If the lid 60 is divided into multiple parts including long and short sides, the sealing strength of the second sealing portion 80 is the sealing strength on the long side portion of the lid sealing surface 67 of the multiple parts.

[0046] 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 80 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 80 is 40 N / 15 mm or more, the state in which the electrode body 20 is sealed by the outer casing 40 is suitably maintained even if the energy storage device 10 is used for, for example, several years (less than 10 years). When the seal strength of the second sealing portion 80 is 85 N / 15 mm or more, the state in which the electrode body 20 is sealed by the outer casing 40 is suitably maintained even if the energy storage device 10 is used for, for example, 10 years or more. The seal strength of the second sealing portion 80 is preferably 150 N / 15 mm or less. The preferred range for the seal strength of the second sealing portion 80 is 40N / 15mm to 150N / 15mm, 50N / 15mm to 150N / 15mm, 60N / 15mm to 150N / 15mm, 70N / 15mm to 150N / 15mm, or 85N / 15mm to 150N / 15mm.

[0047] As shown in Figure 3, the outer film 50 has a lid wrapping portion 50X that is heat-sealed to the lid sealing surface 67 of the lid 60 in the second sealing portion 80. In the outer film 50, a predetermined range including the first edge 50A excluding the lid wrapping portion 50X and a predetermined range including the second edge 50B constitute the first sealing portion 70.

[0048] In the all-solid-state battery described in Patent Document 1, depending on the length of the outer film, wrinkles may form on the outer casing when the outer film and the outer surface of the lid are heat-sealed. Therefore, one of the objectives of this embodiment is to provide an energy storage device 10 that is less prone to wrinkle formation on the outer casing 40.

[0049] In this embodiment, when forming the second sealing portion 80 on the outer casing 40, the length LA of the lid wrapping portion 50X and the length LBX of the lid sealing surface 67 are set to suppress the occurrence of wrinkles in the outer casing 40. The length LBX of the lid sealing surface 67 is the sum of the lengths LB3 of the third surface 63, LB4 of the fourth surface 64, LB5 of the fifth surface 65, and LB6 of the sixth surface 66, as shown in Figure 4. In this embodiment, the ratio RA of length LA to length LBX is preferably 103% or less. Because the difference between length LA and length LBX is small, the outer casing film 50 is less likely to sag. Therefore, when forming the second sealing portion 80 on the outer casing 40, the occurrence of wrinkles in the outer casing 40 is suppressed. The lower limit of the ratio RA is when length LA and length LBX are equal, i.e., 100%.

[0050] In the energy storage device 10, in order to improve the resin filling between the corners of the lid 60 and the outer film 50, the corners of the lid 60 may be crushed after the second sealing portion 80 is formed. In this case, lengths LA and LBX are the lengths of the lid 60 before the corners are crushed.

[0051] <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, and a fourth step. Steps 1 to 4 are carried out, for example, by a manufacturing apparatus for the energy storage device 10.

[0052] In the first step of step S11, the manufacturing apparatus places a cover 60 with electrode terminals 30 attached to both ends of the electrode body 20. Upon completion of the first step, the electrode terminals 30 and the electrodes of the electrode body 20 are electrically connected.

[0053] The second step, S12, is performed after the first step. In the second step, the manufacturing apparatus wraps the outer film 50 around the electrode body 20 and the lid 60.

[0054] The third step, S13, is performed after the second step. In the third step, the manufacturing apparatus forms the first sealing portion 70 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.

[0055] The fourth step, S14, is performed after the third step. The manufacturing apparatus forms the second sealing portion 80 by heat sealing the outer film 50 and the lid 60.

[0056] <1-3. Function and Effects of Energy Storage Devices> In the energy storage device 10, the sealing strength of the second sealing portion 80 is 40 N / 15 mm or more, so the outer film 50 and the lid 60 are firmly bonded together. As a result, the state in which the electrode body 20 is sealed by the outer body 40 is suitably maintained.

[0057] According to the energy storage device 10, since the ratio RA is 103% or less, wrinkles are less likely to form on the outer casing 40.

[0058] [2. Second Embodiment] The energy storage device 200 of the second embodiment differs from the first embodiment in that a poly reservoir is formed in the second sealing portion 80, but the other configurations are the same as those of the first embodiment. Below, the energy storage device 200 of the second embodiment will be described, focusing on the differences from the first embodiment.

[0059] <2-1. Configuration of Energy Storage Devices> Figure 7 is a cross-sectional view of the energy storage device 200 of the second embodiment, viewed from the side of the second sealing portion 80. Figure 8 is a cross-sectional view of the second sealing portion 80, viewed from the electrode body 20 side. Figure 9 is a view of the second sealing portion 80, viewed from the opposite side of the electrode body 20. The energy storage device 200 includes an inner poly reservoir 310 and an outer poly reservoir 320. Note that the through hole 60X is not shown in Figures 8 and 9.

[0060] As shown in Figure 8, the inner poly reservoir 310 is formed between the first surface 61 of the lid 60 and the outer film 50, more specifically, at the boundary between the first surface 61 and the outer film 50. The inner poly reservoir 310 is the portion of the heat-fusible resin layer 53 of the outer film 50 and the resin material constituting the lid 60 that protrudes toward the electrode body 20. The inner poly reservoir 310 is formed, for example, along the longitudinal direction of the lid 60 at the boundary between the first surface 61 of the lid 60 and the outer film 50. In the longitudinal direction of the lid 60, the length of the region where the inner poly reservoir 310 is formed is length HA. In some cases, the inner poly reservoir 310 may be formed intermittently along the longitudinal direction of the lid 60 at the boundary between the first surface 61 of the lid 60 and the outer film 50. In this case, length HA is the sum of the lengths of all the inner poly reservoirs 310 in the longitudinal direction of the lid 60.

[0061] The outer poly reservoir 320 is formed between the second surface 62 of the lid 60 and the outer film 50, more specifically, at the boundary between the second surface 62 and the outer film 50. The outer poly reservoir 320 is the portion of the heat-fusible resin layer 53 of the outer film 50 and the resin material constituting the lid 60 that protrudes on the side opposite to the electrode body 20. The outer poly reservoir 310 is formed, for example, along the longitudinal direction of the lid 60 at the boundary between the second surface 62 of the lid 60 and the outer film 50. In the longitudinal direction of the lid 60, the length of the region where the outer poly reservoir 320 is formed is length HB. Note that the outer poly reservoir 320 may be formed intermittently along the longitudinal direction of the lid 60 at the boundary between the second surface 62 of the lid 60 and the outer film 50. In this case, length HB is the sum of the lengths of all the outer poly reservoirs 320 in the longitudinal direction of the lid 60.

[0062] The inner poly reservoir 310 has endpoints 311 and 312. The outer poly reservoir 320 has endpoints 321 and 322. When the inner poly reservoir 310 and outer poly reservoir 320 are formed on the energy storage device 200, cracks are likely to occur in the heat-sealable resin layer 53 of the outer film 50, starting from endpoints 311, 312, 321, and 322. As a result, the peel strength (seal strength) tends to decrease compared to when the poly reservoir is not formed. When the energy storage device 200 is in use, gas is generated from the electrode body 20, and the outer body 40 expands. When the outer body 40 expands, a force acts to peel the outer film 50 from the lid 60 from the side closer to the electrode body 20. Therefore, in this embodiment, by making the length HA shorter than the length HB, the sealing strength at the boundary between the first surface 61 of the lid 60 and the outer film 50 and its surroundings is increased compared to the sealing strength at the boundary between the second surface 62 of the lid 60 and the outer film 50 and its surroundings. A specific configuration to make the length HA shorter than the length HB can be achieved, for example, by changing the shape of the lid sealing surface 67 of the lid 60.

[0063] As shown in Figure 10, for example, by forming multiple groove-like cuts 63X extending along the longitudinal direction of the lid 60 on the third surface 63 of the lid 60, the length HA can be made shorter than the length HB. The number of cuts 63X formed on the third surface 63 can be arbitrarily selected. Note that the through holes 60X are not shown in Figures 10 to 12.

[0064] As shown in Figure 11, for example, by forming a groove 63Y on the third surface 63 of the lid 60 that extends along the longitudinal direction of the lid 60, the length HA can be made shorter than the length HB. The number of grooves 63Y formed on the third surface 63 can be arbitrarily selected.

[0065] As shown in Figure 12, by forming an inclined surface 63Z on a part of the third surface 63 of the lid 60, which slopes from the second surface 62 towards the first surface 61 and approaches the center of the lid 60 in the height direction, the length HA can be made shorter than the length HB.

[0066] To make the length HA shorter than the length HB, for example, this can be achieved by modifying the process of forming the second sealing portion 80 (sealing process) in the manufacturing method of the energy storage device 200.

[0067] As shown in Figure 13, for example, in the sealing process, the length HA can be made shorter than the length HB by heat sealing the seal bar 400 while it is tilted so that it is closer to the boundary between the first surface 61 and the outer film 50 than to the boundary between the second surface 62 and the outer film 50, thereby forming the second sealing portion 80.

[0068] In another example, in the sealing process, the length HA can be made shorter than the length HB by making the sealing temperature TA of the portion including the boundary between the first surface 61 and the outer film 50 lower than the sealing temperature TB of the portion including the boundary between the second surface 62 and the outer film 50. In this example, the sealing temperatures TA and TB may be changed using one sealing bar, or different sealing bars may be used to change the sealing temperatures TA and TB.

[0069] <2-2. Function and Effects of Energy Storage Devices> According to the energy storage device 200, since length HA is shorter than length HB, the sealing strength at the boundary between the first surface 61 of the lid 60 and the outer film 50 and its surroundings is higher than the sealing strength at the boundary between the second surface 62 of the lid 60 and the outer film 50 and its surroundings. Therefore, even if the outer body 40 expands when the energy storage device 200 is used, the peeling of the outer film 50 from the lid 60 on the electrode body 20 side is suppressed.

[0070] <3. Variant> The embodiments described above are illustrative of possible forms of the energy storage device, cover, and method for manufacturing the energy storage device according to the present invention, and are not intended to limit their forms. The energy storage device, cover, and method for manufacturing the energy storage device according to the present invention may take forms different from those illustrated in each embodiment. One example is a form in which a part of the configuration of each embodiment is replaced, modified, or omitted, or a form in which a new configuration is added to each embodiment. Several examples of modifications of each embodiment are shown below. Note that the following modifications can be combined with each other as long as they do not contradict each other technically.

[0071] <3-1> In the energy storage device 10 of the first embodiment and the energy storage device 200 of the second embodiment, the position where the electrode terminals 30 are arranged can be arbitrarily selected. For example, the electrode terminals 30 may protrude from the first sealing portion 70.

[0072] <3-2> In the energy storage device 10 of the first embodiment, an inner poly reservoir 310 and an outer poly reservoir 320 may be formed, similar to the second embodiment. In this modified example, the length LA of the inner poly reservoir 310 and the length LB of the outer poly reservoir 320 may be equal. In this case, even if the outer casing 40 expands, from the viewpoint of suppressing the peeling of the outer film 50 from the electrode body 20 side to the lid 60, the ratio RB of the thickness MB of the inner poly reservoir 310 to the thickness MA of the heat-fusible resin layer 53 is preferably 200% or less. The thickness MB of the inner poly reservoir 310 is, for example, the length from the first surface 61 of the lid 60 to the top of the inner poly reservoir 310.

[0073] <3-3> In the first embodiment of the energy storage device 10, the shape of the lid sealing surface 67 of the lid 60 can be arbitrarily changed. For example, as shown in Figure 14, inclined surfaces 63XA and 63XB may be formed on a portion of the third surface 63 of the lid 60. Inclined surface 63XA is inclined to approach the center of the lid 60 in the height direction as it moves from the second surface 62 toward the first surface 61. Inclined surface 63XB is inclined to approach the center of the lid 60 in the height direction as it moves from the first surface 61 toward the second surface 62. The inclination angle θAX of inclined surface 63XA with respect to the fourth surface 64 is equal to the inclination angle θBX of inclined surface 63XB with respect to the fourth surface 64. In this modified example, when a poly reservoir is formed in the energy storage device 10, the length LA of the inner poly reservoir 310 and the length LB of the outer poly reservoir 320 are substantially equal.

[0074] <3-4> In the first embodiment of the energy storage device 10, the configuration of the lid 60 can be arbitrarily changed. As shown in Figure 15, the lid 60 may comprise a lid body 60A and a frame 60B that covers the lid body 60A. In this modified example, for example, the material constituting the lid body 60A is metal. The material constituting the frame 60B is, for example, a resin that can suitably seal with the heat-sealable resin layer 53 of the exterior film 50. In this modified example, the third to sixth surfaces 63 to 66 of the lid 60, i.e., the lid sealing surface 67, are formed on the frame 60B. In this modified example as well, it is preferable that the ratio RA of length LA to length LBX is 103% or less.

[0075] <3-5> In the energy storage device 200 of the second embodiment, the shape of the lid 60 can be arbitrarily changed. For example, as shown in Figure 16, the entire third surface 63 may be an inclined surface that slopes towards the center of the lid 60 in the height direction as it moves from the second surface 62 toward the first surface 61. In this modified example, when a poly reservoir is formed in the energy storage device 10, the length LA of the inner poly reservoir 310 becomes shorter than the length LB of the outer poly reservoir 320, thus achieving the same effect as the energy storage device 200 of the second embodiment.

[0076] As shown in Figure 17, inclined surfaces 63YA and 63YB may be formed on a portion of the third surface 63 of the lid 60. The inclined surface 63YA is inclined to approach the center of the lid 60 in the height direction as it moves from the second surface 62 toward the first surface 61. The inclined surface 63YB is inclined to approach the center of the lid 60 in the height direction as it moves from the first surface 61 toward the second surface 62. The inclination angle θAY of the inclined surface 63YA with respect to the fourth surface 64 is greater than the inclination angle θBY of the inclined surface 63YB with respect to the fourth surface 64. In this modification, when a poly reservoir is formed in the energy storage device 10, the length LA of the inner poly reservoir 310 is shorter than the length LB of the outer poly reservoir 320, thus achieving the same effect as the energy storage device 200 of the second embodiment.

[0077] <3-6> The energy storage device 10 of the first embodiment and the energy storage device 200 of the second embodiment may have an adhesive film 500 placed between the outer film 50 and the lid 60 in order to suitably bond the outer film 50 and the lid 60. In this modified example, for example, the lid 60 with the adhesive film 500 bonded to it is attached to the openings 40A at both ends of the outer body 40, after which the second sealing portion 80 is formed.

[0078] Figure 18 is a cross-sectional view of a modified energy storage device 200 of the second embodiment, viewed from the side of the second sealing portion 80. Figure 19 is a front view of the lid 60 with the adhesive film 500 of Figure 18 attached. The adhesive film 500 has an adhesive portion 510 that is bonded to the outer film 50 and the lid 60 in the second sealing portion 80, and a protruding portion 520 that protrudes from the lid sealing surface 67 of the lid 60. Note that the protruding portion 520 is not shown in Figure 19. The adhesive film 500 is wrapped around the lid 60, for example, so as to cover the entire surface of the lid sealing surface 67 of the lid 60. In this modified example, the inner poly reservoir 310 is formed between the outer film 50 and the first surface 61 of the lid 60, more specifically, at the boundary between the outer film 50 and the adhesive film 500. The outer poly reservoir 320 is formed between the outer film 50 and the second surface 62 of the lid 60, more specifically, at the boundary between the outer film 50 and the adhesive film 500. Because the adhesive film 500 has protrusions 520, it is wider overall than the lid sealing surface 67 of the lid 60. This allows the adhesive film 500 to be easily adhered to the lid 60. Furthermore, since the corners of the boundary between surfaces of the lid 60 are covered by the adhesive film 500, the adhesion between the lid 60 and the adhesive film 500 is enhanced. Note that the inner poly reservoir 310 and the outer poly reservoir 320 may also be formed between the lid 60 and the adhesive film 500.

[0079] The adhesive film 500 can be arbitrarily selected as long as it is a film that can adhere the outer film 50 and the lid 60. Preferably, the adhesive film 500 is a laminate (laminate 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 500 can be the same as those for the heat-fusible resin layer 53. The materials constituting the heat-fusible resin layers on both sides of the adhesive film 500 may be the same material or different materials, and are appropriately selected in accordance with the materials constituting the heat-fusible resin layer 53 of the outer film 50 and the materials constituting the lid 60. Preferably, the material constituting the heat-fusible resin layer on the side of the adhesive film 500 that is adhered to the lid 60 is an acid-modified polyolefin resin graft-modified with an acid such as maleic anhydride. It is preferable that the heat-sealable resin layer of the adhesive film 500 that is bonded to the outer film 50 is made of the same material as the material that constitutes the heat-sealable resin layer 53 of the outer film 50.

[0080] 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.

[0081] The adhesive film 500 preferably has adhesive properties. When the second sealing portion 80 is formed with the adhesive film 500 positioned between the outer film 50 and the lid 60, the position of the adhesive film 500 relative to the lid 60 and the outer film 50 is less likely to shift. Adhesion can be imparted to the adhesive film 500 by including an adhesive-imparting resin in the heat-fusible resin layer of the adhesive film 500. Examples of adhesive-imparting resins include amorphous polyolefins. Examples of amorphous polyolefins include amorphous polypropylene or copolymers of amorphous propylene and other α-olefins. The content of the adhesive-imparting resin relative to the base material constituting the heat-fusible resin is preferably 10 to 20% by weight or less.

[0082] In this modified example, when forming the second sealing portion 80 on the outer casing 40, the length LA of the lid wrapping portion 50X (see Figure 3) and the length LCX of the adhesive portion 510 may be set to suppress the occurrence of wrinkles in the outer casing 40. The length LCX of the adhesive portion 510 is the sum of lengths LC3, LC4, LC5, and LC6. Length LC3 is the length of the portion of the adhesive portion 510 that is bonded to the third surface 63. Length LC4 is the length of the portion of the adhesive portion 510 that is bonded to the fourth surface 64. Length LC5 is the length of the portion of the adhesive portion 510 that is bonded to the fifth surface 65. Length LC6 is the length of the portion of the adhesive portion 510 that is bonded to the sixth surface 66. In this modified example, the ratio RC of length LA to length LCX is preferably 103% or less. Because the difference between length LA and length LCX is small, the outer casing film 50 is less likely to sag. Therefore, when forming the second sealing portion 80 on the outer casing 40, the occurrence of wrinkles in the outer casing 40 is suppressed. The lower limit of the ratio RC is 100%, i.e., when the length LA and the length LCX are equal.

[0083] [4. Examples] The inventors of the present invention conducted first and second tests on the energy storage devices of the examples and comparative examples. The first test was to measure the seal strength of the second sealing portion 80. The second test was to check for the presence or absence of wrinkles in the outer casing 40. For the sake of explanation, in the following description, elements constituting the energy storage devices of the examples and comparative examples that are the same as those in the embodiment will be denoted by the same reference numerals as in the embodiment.

[0084] <4-1. First Examination> In the first test, the energy storage devices of Examples 1 to 7 and Comparative Examples 1 and 2 were manufactured, and cross-sectional observations were performed to observe the poly buildup. The seal strength was also measured by peeling the outer film 50 from the first surface 61 to the second surface 62 of the lid 60 using an Autograph (AG-Xplus manufactured by Shimadzu Corporation). The method for measuring the seal strength was as follows: The lid 60 and outer film 50 to be measured were cut from the manufactured energy storage devices 10 of the examples and comparative examples, the outer film 50 was cut to a width of 15 mm in the measurement direction, and the devices were chucked so that the lid 60 was on the lower side of the Autograph chuck and the outer film 50 was on the upper side, and the measurement was performed at 300 mm / min. The specifications of the energy storage devices of Examples 1 to 5 and Comparative Examples 1 and 2 are as follows.

[0085] The energy storage devices of Examples 1, 5, and 6 are energy storage devices 10 according to the first embodiment. The energy storage devices of Examples 2 to 4 and 7 are energy storage devices 200 according to the second embodiment. The lid 60 of the energy storage devices 200 of Examples 2 and 7 has the shape shown in Figure 12, with an inclined surface 63Z formed on the third surface 63. The lid 60 of the energy storage device 200 of Example 3 has the shape shown in Figure 10, with a notch 63X formed on the third surface 63. The lid 60 of the energy storage device 200 of Example 4 has the shape shown in Figure 11, with a groove 63Y formed on the third surface 63.

[0086] The sealing conditions for the second sealing portion 80 of the energy storage devices in Examples 1 to 4 are a temperature of 220°C, a time of 5 seconds, and a pressure of 0.4 MPa. The sealing conditions for the second sealing portion 80 of the energy storage device in Example 5 are a temperature of 230°C, a time of 5 seconds, and a pressure of 0.4 MPa. The sealing conditions for the second sealing portion 80 of the energy storage device in Example 6 are a temperature of 200°C, a time of 5 seconds, and a pressure of 0.4 MPa. The sealing conditions for the second sealing portion 80 of the energy storage device in Example 7 are a temperature of 210°C, a time of 5 seconds, and a pressure of 0.4 MPa.

[0087] The energy storage devices of Examples 1, 5, and 6 have an inner poly reservoir 310 and an outer poly reservoir 320, with lengths LA and LB being equal. The energy storage device of Example 1 has a ratio RB of 160%. The energy storage device of the fifth embodiment has a ratio RB of 240%. The energy storage device of Example 6 has a ratio RB of 260%. The energy storage devices of Examples 2-4 and 7 have an inner poly reservoir 310 and an outer poly reservoir 320, with length LA being shorter than length LB.

[0088] The specifications of the energy storage device of Comparative Example 1 are the same as those of the energy storage device of Example 1, except for the sealing conditions of the second sealing portion 80. The sealing conditions of the second sealing portion 80 of the energy storage device of Comparative Example 1 are a temperature of 190°C, a time of 5 seconds, and a pressure of 0.4 MPa. The energy storage device of Comparative Example 1 does not have an inner poly reservoir 310 or an outer poly reservoir 320.

[0089] The specifications of the energy storage device of Comparative Example 2 are the same as those of the energy storage devices of Examples 2 to 4, except for the sealing conditions of the second sealing portion 80. The sealing conditions of the second sealing portion 80 of the energy storage device of Comparative Example 2 are a temperature of 220°C, a time of 3 seconds, and a pressure of 0.4 MPa. The energy storage device of Comparative Example 2 has an inner poly reservoir 310 and an outer poly reservoir 320, with length LA being longer than length LB.

[0090] Figure 20 is a table showing the test results of the first test. In the energy storage devices of Examples 1 to 7, it was confirmed that high seal strength could be obtained for the second sealing portion 80. From the test results of the energy storage device of Example 1, it was confirmed that even if the lengths LA and LB were equal, high seal strength could be achieved by making the ratio RB 200% or less. From the test results of the energy storage devices of Examples 2 to 4, it was confirmed that high seal strength could be achieved by making the length LA shorter than the length LB. However, it was confirmed that the energy storage devices of Examples 5 and 6 had lower seal strength of the second sealing portion 80 than the energy storage device of Example 1. This is thought to be partly due to the ratio RB being 200% or more.

[0091] <4-2. Second Examination> In the second test, the energy storage devices of Examples 8 and 9, and the energy storage device of Comparative Example 3 were manufactured, and the number of wrinkles in the outer casing 40 was visually confirmed. The specifications of the energy storage devices of Examples 8 and 9, and the energy storage device of Comparative Example 3 are as follows.

[0092] The energy storage devices of Examples 8 and 9 are the energy storage device 10 according to the first embodiment. In the energy storage devices of Examples 8 and 9, the sealing conditions for the first sealing portion 70 are a temperature of 210°C, a time of 5 seconds, and a pressure of 0.5 MPa, and the sealing conditions for the second sealing portion 80 are a temperature of 220°C, a time of 5 seconds, and a pressure of 0.5 MPa. The energy storage device of Example 8 has a ratio RA of 100%. The energy storage device of Example 9 has a ratio RA of 103%.

[0093] The specifications of the energy storage device in Comparative Example 3 are the same as those of the energy storage devices in Examples 8 and 9, except for the ratio RA. The ratio RA of the energy storage device in Comparative Example 3 is 105%.

[0094] Figure 21 is a table showing the test results for the second test. In Figure 18, "○" in the "Wrinkle Occurrence" column indicates that no wrinkles were present, "△" indicates that wrinkles occurred in three or fewer locations, and "×" indicates that wrinkles occurred in four or more locations.

[0095] In Examples 8 and 9, it was confirmed that no wrinkles occurred in the outer casing 40, or that the occurrence of wrinkles was suppressed. This is thought to be because the energy storage devices in Examples 8 and 9 had a ratio RA of 103% or less. [Explanation of symbols]

[0096] 10,200: Energy storage devices 20: Electrode body 40: Exterior 50: Exterior film 53: Heat-fusible resin layer 60: Lid 61: 1st page 62: 2nd side 63X: Cut 63XA: Inclined surface 63XB: Inclined surface 63YA: Inclined surface 63YB: Inclined surface 63Y: Groove 63Z: Inclined surface 67: Lid sealing surface 70: First sealing section 80: Second sealing section 310: Inner poly reservoir 320: Outer poly reservoir 500: Adhesive film 510: Adhesive part

Claims

1. A lid which is one of the components that make up the outer casing for an energy storage device that seals an electrode body, The aforementioned outer casing for the energy storage device includes an outer film that is wrapped around the electrode body so as to have a rectangular opening in plan view, In each component constituting the outer casing for the energy storage device, the side facing the electrode body is designated as the inside, the side opposite to the side facing the electrode body is designated as the outside, the direction along the long side of the opening is designated as the longitudinal direction, and the direction along the short side of the opening is designated as the short direction. The lid is positioned in the opening, has a rectangular shape in plan view, and includes a lid sealing surface that seals with the outer film. The lid sealing surface comprises a first sealing surface that constitutes one of the longitudinal surfaces, a second sealing surface that constitutes the other longitudinal surface, a third sealing surface that constitutes one of the short surfaces, and a fourth sealing surface that constitutes the other short surface. The inner end region of the first sealing surface is provided with an inclined surface that slopes from the outside towards the inside, approaching the center of the lid in the shorter direction. Cover.

2. A lid which is one of the components that make up the outer casing for an energy storage device that seals an electrode body, The aforementioned outer casing for the energy storage device includes an outer film that is wrapped around the electrode body so as to have a rectangular opening in plan view, In each component constituting the outer casing for the energy storage device, the side facing the electrode body is designated as the inside, the side opposite to the side facing the electrode body is designated as the outside, the direction along the long side of the opening is designated as the longitudinal direction, and the direction along the short side of the opening is designated as the short direction. The lid is positioned in the opening, has a rectangular shape in plan view, and includes a lid sealing surface that seals with the outer film. The lid sealing surface comprises a first sealing surface that constitutes one of the longitudinal surfaces, a second sealing surface that constitutes the other longitudinal surface, a third sealing surface that constitutes one of the short surfaces, and a fourth sealing surface that constitutes the other short surface. The entire first sealing surface is an inclined surface that slopes from the outside to the inside, approaching the center of the lid in the shorter direction. Cover.

3. A lid which is one of the components that make up the outer casing for an energy storage device that seals an electrode body, The aforementioned outer casing for the energy storage device includes an outer film that is wrapped around the electrode body so as to have a rectangular opening in plan view, In each component constituting the outer casing for the energy storage device, the side facing the electrode body is designated as the inside, the side opposite to the side facing the electrode body is designated as the outside, the direction along the long side of the opening is designated as the longitudinal direction, and the direction along the short side of the opening is designated as the short direction. The lid is positioned in the opening, has a rectangular shape in plan view, and includes a lid sealing surface that seals with the outer film. The lid sealing surface comprises a first sealing surface that constitutes one of the longitudinal surfaces, a second sealing surface that constitutes the other longitudinal surface, a third sealing surface that constitutes one of the short surfaces, and a fourth sealing surface that constitutes the other short surface. The inner end region of the first sealing surface is provided with a first inclined surface that slopes from the outside towards the inside, approaching the center of the lid in the short direction, The outer end region of the first sealing surface is provided with a second inclined surface that slopes from the inside outward so as it approaches the center of the lid in the short direction, Cover.

4. A lid which is one of the components that make up the outer casing for an energy storage device that seals an electrode body, The aforementioned outer casing for the energy storage device includes an outer film that is wrapped around the electrode body so as to have a rectangular opening in plan view, In each component constituting the outer casing for the energy storage device, the side facing the electrode body is designated as the inside, the side opposite to the side facing the electrode body is designated as the outside, the direction along the long side of the opening is designated as the longitudinal direction, and the direction along the short side of the opening is designated as the short direction. The lid is positioned in the opening, has a rectangular shape in plan view, and includes a lid sealing surface that seals with the outer film. The lid sealing surface comprises a first sealing surface that constitutes one of the longitudinal surfaces, a second sealing surface that constitutes the other longitudinal surface, a third sealing surface that constitutes one of the short surfaces, and a fourth sealing surface that constitutes the other short surface. The inner end region of the first sealing surface is provided with a first inclined surface that slopes from the outside towards the inside, approaching the center of the lid in the short direction, The outer end region of the first sealing surface is provided with a second inclined surface that slopes from the inside outward so as it approaches the center of the lid in the short direction, The inclination angle of the first inclined surface is greater than the inclination angle of the second inclined surface. Cover.

5. A lid which is one of the components that make up the outer casing for an energy storage device that seals an electrode body, The aforementioned outer casing for the energy storage device includes an outer film that is wrapped around the electrode body so as to have a rectangular opening in plan view, In each component constituting the outer casing for the energy storage device, the side facing the electrode body is designated as the inside, the side opposite to the side facing the electrode body is designated as the outside, the direction along the long side of the opening is designated as the longitudinal direction, and the direction along the short side of the opening is designated as the short direction. The lid is positioned in the opening, has a rectangular shape in plan view, and includes a lid sealing surface that seals with the outer film. The lid sealing surface comprises a first sealing surface that constitutes one of the longitudinal surfaces, a second sealing surface that constitutes the other longitudinal surface, a third sealing surface that constitutes one of the short surfaces, and a fourth sealing surface that constitutes the other short surface. The first sealing surface has groove-like cuts along the longitudinal direction. Cover.

6. A lid which is one of the components that make up the outer casing for an energy storage device that seals an electrode body, The aforementioned outer casing for the energy storage device includes an outer film that is wrapped around the electrode body so as to have a rectangular opening in plan view, In each component constituting the outer casing for the energy storage device, the side facing the electrode body is designated as the inside, the side opposite to the side facing the electrode body is designated as the outside, the direction along the long side of the opening is designated as the longitudinal direction, and the direction along the short side of the opening is designated as the short direction. The lid is positioned in the opening, has a rectangular shape in plan view, and includes a lid sealing surface that seals with the outer film. The lid sealing surface comprises a first sealing surface that constitutes one of the longitudinal surfaces, a second sealing surface that constitutes the other longitudinal surface, a third sealing surface that constitutes one of the short surfaces, and a fourth sealing surface that constitutes the other short surface. The first sealing surface has grooves along the longitudinal direction. Cover.

7. Electrode body and The device comprises an outer casing for a power storage device that seals the electrode body, A power storage device wherein the electrode body is sealed by the power storage device casing, The outer casing for the energy storage device comprises an outer film wrapped around the electrode body such that it has a rectangular opening in plan view, A lid, which is rectangular in shape when viewed from above, is placed in the aforementioned opening, A first sealing portion in which the opposing surfaces of the outer film are sealed together, It includes a second sealing portion in which the opposing surfaces of the lid and the outer film are sealed together, In each component constituting the outer casing for the energy storage device, the side facing the electrode body is designated as the inside, the side opposite to the side facing the electrode body is designated as the outside, the direction along the long side of the opening is designated as the longitudinal direction, and the direction along the short side of the opening is designated as the short direction. The lid has a lid sealing surface in the second sealing portion that faces and seals the outer film, The lid sealing surface comprises a first sealing surface that constitutes one of the longitudinal surfaces, a second sealing surface that constitutes the other longitudinal surface, a third sealing surface that constitutes one of the short surfaces, and a fourth sealing surface that constitutes the other short surface. Between the inner end of the first sealing surface and the outer film, an inner poly reservoir is formed along the longitudinal direction. Between the outer edge of the first sealing surface and the outer film, an outer poly reservoir is formed along the longitudinal direction. The sealing strength between the first sealing surface and the outer film is 40 N / 15 mm or more. Energy storage device.

8. Electrode body and The device comprises an outer casing for a power storage device that seals the electrode body, A power storage device wherein the electrode body is sealed by the power storage device casing, The outer casing for the energy storage device comprises an outer film wrapped around the electrode body such that it has a rectangular opening in plan view, A lid, which is rectangular in shape when viewed from above, is placed in the aforementioned opening, A first sealing portion in which the opposing surfaces of the outer film are sealed together, It includes a second sealing portion in which the opposing surfaces of the lid and the outer film are sealed together, In each component constituting the outer casing for the energy storage device, the side facing the electrode body is designated as the inside, the side opposite to the side facing the electrode body is designated as the outside, the direction along the long side of the opening is designated as the longitudinal direction, and the direction along the short side of the opening is designated as the short direction. The lid has a lid sealing surface in the second sealing portion that faces and seals the outer film, The lid sealing surface comprises a first sealing surface that constitutes one of the longitudinal surfaces, a second sealing surface that constitutes the other longitudinal surface, a third sealing surface that constitutes one of the short surfaces, and a fourth sealing surface that constitutes the other short surface. Between the inner end of the first sealing surface and the outer film, an inner poly reservoir is formed along the longitudinal direction. Between the outer edge of the first sealing surface and the outer film, an outer poly reservoir is formed along the longitudinal direction. The length of the inner poly reservoir is shorter than the length of the outer poly reservoir. Energy storage device.

Images