Power storage device, outer packaging film, and method of manufacturing power storage device

Abstract

To provide a power storage device that has high accuracy of a position of a lid body with respect to an outer packaging film, the outer packaging film used in the power storage device, and a method of manufacturing the power storage device.SOLUTION: A power storage device comprises an electrode body, and an outer packaging body for sealing the electrode body. The outer packaging body has an outer packaging film for packaging the electrode body in such a manner that an opening is formed, and a lid body that is arranged in the opening. The outer packaging film has a first mark that is formed to correspond to at least a part of a corner of the lid body.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an electricity storage device, an exterior film, and a method for manufacturing an electricity storage device. [Background technology]

[0002] Patent Document 1 discloses an example of an electricity storage device. This electricity storage device includes an electrode body and an exterior body that seals the electrode body. The exterior body includes an exterior film that wraps the electrode body so that an opening is formed, and a lid body that is placed on the opening. The exterior film and the lid body are joined together. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-123686 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned power storage device, after the electrode body is wrapped in an exterior film, a lid body is placed on the opening of the exterior film. Therefore, the position of the lid body relative to the exterior film may deviate from a specified position. If the position of the lid body relative to the exterior film deviates from the specified position, various problems may occur, such as a reduction in the bonding area between the exterior film and the lid body.

[0005] An object of the present invention is to provide an electricity storage device in which a lid body is positioned with high accuracy relative to an exterior film, an exterior film used in this electricity storage device, and a method for manufacturing this electricity storage device. [Means for solving the problem]

[0006] An energy storage device according to a first aspect of the present invention is an energy storage device comprising an electrode body and an exterior body that seals the electrode body, wherein the exterior body comprises an exterior film that wraps the electrode body so as to form an opening, and a lid body that is placed in the opening, and the exterior film has a first mark formed to correspond to at least a portion of a corner of the lid body.

[0007] An electricity storage device according to a second aspect of the present invention is the electricity storage device according to the first aspect, wherein the first mark is at least one of a crease, a line, and a cut that does not penetrate the exterior film.

[0008] An electricity accumulation device according to a third aspect of the present invention is the electricity accumulation device according to the first or second aspect, wherein the first mark is formed in an area including at least an end of the corner portion of the lid.

[0009] An electricity storage device according to a fourth aspect of the present invention is the electricity storage device according to any one of the first to third aspects, wherein the exterior film has a second mark formed so as to correspond to at least a part of a corner of the electrode body.

[0010] An electricity accumulation device according to a fifth aspect of the present invention is the electricity accumulation device according to the fourth aspect, wherein the first mark and the second mark are connected to each other.

[0011] An exterior film according to a sixth aspect of the present invention is an exterior film used as an exterior body for an electricity storage device, the electricity storage device comprising an electrode body and a lid body, and the exterior film having a first mark formed to correspond to at least a portion of a corner of the lid body.

[0012] An exterior film according to a seventh aspect of the present invention is the exterior film according to the sixth aspect, wherein the first mark is at least one of a crease, a line, and a cut that does not penetrate the exterior film.

[0013] An exterior film according to an eighth aspect of the present invention is the exterior film according to the sixth or seventh aspect, wherein the first mark is formed in an area that includes at least an end of the corner portion of the lid.

[0014] An exterior film according to a ninth aspect of the present invention is the exterior film according to any one of the sixth to eighth aspects, and has a second mark formed so as to correspond to at least a part of a corner of the electrode body.

[0015] An exterior film according to a tenth aspect of the present invention is the exterior film according to the ninth aspect, wherein the first mark and the second mark are connected to each other.

[0016] A manufacturing method for an electricity storage device according to an eleventh aspect of the present invention is a manufacturing method for an electricity storage device comprising an electrode body and an exterior body that seals the electrode body, wherein the exterior body comprises an exterior film that wraps the electrode body so as to form an opening, and a lid body that is placed in the opening, and the exterior film has a first mark formed to correspond to at least a portion of a corner of the lid body, and the manufacturing method for the electricity storage device includes a mark forming step of forming the first mark in the exterior film.

[0017] A manufacturing method for an electricity storage device according to a twelfth aspect of the present invention is a manufacturing method for an electricity storage device according to the eleventh aspect, and includes an arrangement step, which is performed after the mark forming step, of arranging the lid body on the exterior film so that a corner of the lid body coincides with the first mark, and a packaging step, which is performed after the arrangement step, of wrapping the electrode body and the lid body in the exterior film while folding the exterior film along the first mark. Effect of the Invention

[0018] The electricity storage device, the exterior film used in the electricity storage device, and the manufacturing method for the electricity storage device according to the present invention can contribute to improving the positional accuracy of the lid body relative to the exterior film. [Brief description of the drawings]

[0019] [Figure 1A] FIG. 1 is a perspective view of an electricity storage device according to an embodiment. [Figure 1B] 1B is a diagram showing a method for measuring the seal strength of a second sealing portion of the electricity storage device in FIG. 1A. [Diagram 2] 1B is a perspective view of an electrode body included in the electricity storage device of FIG. 1A. [Diagram 3] 1B is a cross-sectional view showing a layer structure of an exterior film included in the electricity storage device of FIG. 1A. [Figure 4] 1B is a perspective view of a lid provided in the electricity storage device of FIG. 1A. [Diagram 5] FIG. 1B is a diagram showing the state in which the exterior film of the power storage device of FIG. 1A is unfolded. [Figure 6] 6 is a schematic diagram of a crease forming device for forming creases in the exterior film of FIG. 5. [Figure 7] 4 is a flowchart showing an example of a method for manufacturing the electricity storage device in FIG. 1A. [Figure 8] FIG. 8 is a diagram relating to the third step in FIG. 7. [Figure 9] FIG. 8 is a diagram relating to the fourth step in FIG. 7. [Figure 10] FIG. 13 is a diagram showing a state in which an exterior film provided on an electricity storage device according to a modified example is unfolded. [Figure 11] FIG. 13 is a diagram showing a state in which an exterior film provided in an electricity storage device according to another modified example is unfolded. [Figure 12] FIG. 13 is a schematic diagram showing another example of a crease forming device. [Figure 13] A table showing the results of the first, second and third tests. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an electric storage device according to one embodiment of the present invention will be described with reference to the drawings. In this specification, a numerical range indicated by "to" means "greater than or equal to" or "less than or equal to." For example, the expression "2 to 15 mm" means 2 mm or more and 15 mm or less. In this specification, a corner includes a right-angled corner as well as a corner formed with a rounded surface.

[0021] [1. First embodiment] <1-1. Configuration of the power storage device> FIG. 1A is a plan view that shows a schematic diagram of an electricity storage device 10 of a first embodiment. FIG. 1B is a diagram that shows a method for measuring the seal strength of a second sealing portion 80 of the electricity storage device 10. FIG. 2 is a perspective view of an electrode body 20 included in the electricity storage device of FIG. 1A. FIG. 3 is a cross-sectional view showing a layer structure of an exterior film 50 included in the electricity storage device 10 of FIG. 1A. FIG. 4 is a perspective view of a lid body 60 included in the electricity storage device 10 of FIG. 1A. FIG. 5 is a diagram showing a state in which the exterior film 50 included in the electricity storage device 10 of FIG. 1A is unfolded. In FIG. 1A, the direction of the arrow UD indicates the thickness direction of the electricity storage device 10, the direction of the arrow LR indicates the width direction of the electricity storage device 10, and the direction of the arrow FB indicates the depth direction of the electricity storage device 10. The directions indicated by the arrows UDLRFB are common to the following figures.

[0022] The power storage device 10 includes an electrode body 20, an electrode terminal 30, and an exterior body 40. The electrode body 20 includes electrodes (positive and negative electrodes) constituting a power storage member such as a lithium ion battery, a capacitor, an all-solid-state battery, a semi-solid battery, a quasi-solid battery, a polymer battery, an all-resin battery, a lead-acid battery, a nickel-metal hydride battery, a nickel-cadmium battery, a nickel-iron battery, a nickel-zinc battery, a silver oxide-zinc battery, a metal-air battery, a polyvalent cation battery, or a capacitor, and a separator. In this embodiment, the shape of the electrode body 20 is an approximately rectangular parallelepiped. Note that the term "approximately rectangular parallelepiped" includes, in addition to a complete rectangular parallelepiped, a solid body that can be regarded as a rectangular parallelepiped by modifying the shape of a part of the outer surface, for example. The shape of the electrode body 20 may be, for example, a cylinder or a polygonal prism.

[0023] In this embodiment, the power storage device 10 includes two electrode terminals 30. The electrode terminals 30 are metal terminals used for inputting and outputting electric power in the electrode body 20. One end of the electrode terminal 30 is electrically connected to an electrode (positive electrode or negative electrode) included in the electrode body 20. The other end of the electrode terminal 30 protrudes outward from an edge of the exterior body 40, for example. Note that the electrode terminal 30 may not protrude from the exterior body 40, for example, as long as it is capable of inputting and outputting electric power to and from the electrode body 20. When the cover body 60 described later is made of, for example, a metal, the cover body 60 may also function as the electrode terminal 30. In this case, the cover body 60 having the function as an electrode terminal may or may not protrude from the exterior body 40.

[0024] As shown in FIG. 2, in this embodiment, the electrode body 20 has a front surface 21, a rear surface 22, an upper surface 23, a lower surface 24, a first side surface 25, and a second side surface 26. The front surface 21 faces one of the lid bodies 60. The rear surface 22 faces the other of the lid bodies 60. The upper surface 23 constitutes one of a pair of first surfaces 41 of the exterior body 40 described later. The lower surface 24 constitutes the other of the pair of first surfaces 41 of the exterior body 40 described later. The first side surface 25 constitutes one of a pair of second surfaces 42 of the exterior body 40 described later. The second side surface 26 constitutes the other of the pair of second surfaces 42 of the exterior body 40 described later.

[0025] The electrode body 20 has corners 20A, 20B, 20C, and 20D. Corners 20A to 20D have rounded surfaces. At least one of corners 20A to 20D may have a rounded surface. Corner 20A is formed at the boundary between upper surface 23 and first side surface 25. Corner 20B is formed at the boundary between upper surface 23 and second side surface 26. Corner 20C is formed at the boundary between first side surface 25 and lower surface 24. Corner 20D is formed at the boundary between second side surface 26 and lower surface 24. In FIG. 2, the rounded shapes of corners 20A to 20D are omitted for the sake of simplicity.

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

[0027] The exterior body 40 seals the electrode body 20. The exterior body 40 includes an exterior film 50 and a pair of lid bodies 60. The exterior film 50 wraps the electrode body 20 so as to form a pair of openings 40A. In this embodiment, the exterior film 50 is wrapped around the electrode body 20 so as to form a pair of openings 40A. The electrode body 20 may be housed inside the exterior film 50 configured in a cylindrical shape so as to form a pair of openings 40A, and the openings 40A may be closed by the lid body 60. The pair of lid bodies 60 are disposed on the sides of the electrode body 20 so as to close the pair of openings 40A.

[0028] From the viewpoint of suitable adhesion to the lid 60, it is preferable that the adhesive film 31 is bonded to the electrode terminal 30. The adhesive film 31 can be selected arbitrarily as long as it is a film capable of bonding the electrode terminal 30 made of metal and the lid 60 made of resin. For example, the adhesive film 31 can be a polyolefin resin such as a polyethylene resin or a polypropylene resin, a cyclic polyolefin resin, or an acid-modified polyolefin resin obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The adhesive film 31 can be a single layer or two or more layers of these films. In this embodiment, the adhesive film 31 is bonded to almost the entire portion of the electrode terminal 30 covered by the lid 60.

[0029] For example, there is a method of forming a storage portion (recess) for storing the electrode body 20 in the exterior film 50 through cold forming. However, it is not necessarily easy to form a deep storage portion by such a method. If an attempt is made to form a deep storage portion (recess) by cold forming (for example, a forming depth of 15 mm), pinholes or cracks will occur in the exterior film 50, which is likely to cause a decrease in battery performance. On the other hand, the exterior body 40 seals the electrode body 20 by wrapping the exterior film 50 around the electrode body 20, so that the electrode body 20 can be easily sealed regardless of the thickness of the electrode body 20. In addition, in order to reduce the dead space between the electrode body 20 and the exterior film 50 to improve the volumetric energy density of the power storage device 10, it is preferable that the exterior film 50 is wrapped so as to contact the outer surface of the electrode body 20. In addition, in an all-solid-state battery, it is necessary to apply a high pressure uniformly from the outer surface of the battery to exhibit battery performance, so it is necessary to eliminate the space between the electrode body 20 and the exterior film 50, and therefore it is preferable that the exterior film 50 is wrapped so as to contact the outer surface of the electrode body 20.

[0030] 3, the exterior 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 this order. Note that the exterior film 50 does not need to include all of these layers, and for example, the barrier layer 52 may not be included. That is, the exterior film 50 only needs to be made of a material that is flexible and easily bendable, and may be made of, for example, a resin film. Note that the exterior film 50 is preferably heat-sealable.

[0031] The base layer 51 included in the exterior film 50 is a layer for imparting heat resistance to the exterior film 50 and suppressing the occurrence of pinholes that may occur during processing or distribution. The base layer 51 is configured to include at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer. For example, the base layer 51 includes at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer, so that the barrier layer 52 can be protected during processing of the exterior film 50 and breakage of the exterior film 50 can be suppressed. In addition, from the viewpoint of increasing the tensile elongation of the exterior film 50, the stretched polyester resin layer is preferably a biaxially stretched polyester resin layer, and the stretched polyamide resin layer is preferably a biaxially stretched polyamide resin layer. Furthermore, in terms of excellent puncture strength or impact strength, the stretched polyester resin layer is more preferably a biaxially stretched polyethylene terephthalate (PET) film, and the stretched polyamide resin layer is more preferably a biaxially stretched nylon (ONy) film. The base layer 51 may be configured to include both a stretched polyester resin layer and a stretched polyamide resin layer. The thickness of the base layer 51 is, for example, preferably 5 to 300 μm, and more preferably 5 to 150 μm, from the viewpoint of film strength.

[0032] The barrier layer 52 is a layer that at least prevents the intrusion of moisture. The barrier layer 52 is bonded to the base layer 51 via, for example, an adhesive layer 54. Examples of the barrier layer 52 include metal foil, vapor deposition film, and resin layer having barrier properties. Examples of the vapor deposition film include metal vapor deposition film, inorganic oxide vapor deposition film, and carbon-containing inorganic oxide vapor deposition film, and examples of the resin layer include fluorine-containing resins such as polyvinylidene chloride, polymers mainly composed of chlorotrifluoroethylene (CTFE), polymers mainly composed of tetrafluoroethylene (TFE), polymers having fluoroalkyl groups, and polymers mainly composed of fluoroalkyl units, and ethylene-vinyl alcohol copolymers. Examples of the barrier layer 52 include resin films having at least one of these vapor deposition films and resin layers. The barrier layer 52 may be provided in a plurality of layers. It is preferable that the barrier layer 52 includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 52 include aluminum alloys, stainless steel, titanium steel, and steel plates. When used as a metal foil, it is preferable that the material contains at least one of an aluminum alloy foil and a stainless steel foil.

[0033] In the barrier layer 52, the layer made of the above-mentioned metal material may contain recycled metal material. Examples of recycled metal material include recycled aluminum alloy, stainless steel, titanium steel, or steel plate. These recycled materials can be obtained by known methods. The recycled aluminum alloy material can be obtained by the manufacturing method described in International Publication No. 2022 / 092231. The barrier layer 52 may be made of only recycled materials, or may be made of a mixed material of recycled materials and virgin materials. Note that recycled metal materials refer to metal materials that have been made reusable by collecting, isolating, and refining various products used in the city and waste from the manufacturing process. In addition, virgin metal materials refer to new metal materials refined from natural metal resources (raw materials) and are not recycled materials.

[0034] From the viewpoint of improving the formability or conformability of the exterior film 50, the aluminum alloy foil is preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy, and from the viewpoint of further improving the formability or conformability, the aluminum alloy foil is preferably an iron-containing aluminum alloy foil. In the iron-containing aluminum alloy foil (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, and more preferably 0.5 to 2.0% by mass. By making the iron content 0.1% by mass or more, an exterior film 50 having better formability can be obtained. By making the iron content 9.0% by mass or less, an exterior film 50 having better flexibility can be obtained. Examples of the soft aluminum alloy foil include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Silicon, magnesium, copper, manganese, etc. may be added as necessary. Softening can be performed by annealing treatment, etc. From the viewpoint of improving the mechanical strength of the exterior film 50, it is more preferable that the aluminum alloy foil is a hard aluminum alloy foil composed of, for example, a work-hardened aluminum alloy. Examples of the hard aluminum alloy foil include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-H18, JIS H4160:1994 A8079H-H18, JIS H4000:2014 A8021P-H14, or JIS H4000:2014 A8079P-H14.

[0035] Examples of the stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. From the viewpoint of providing an exterior film 50 with excellent formability, the stainless steel foil is preferably made of austenitic stainless steel.

[0036] Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, and SUS316L, and among these, SUS304 is particularly preferred.

[0037] In the case of a metal foil, the thickness of the barrier layer 52 is sufficient as long as it at least functions as a barrier layer that prevents moisture from penetrating, and may be, for example, about 5 to 200 μm. The thickness of the barrier layer 52 is preferably about 85 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, and particularly preferably about 35 μm or less. The thickness of the barrier layer 52 is preferably about 10 μm or more, even more preferably about 20 μm or more, and more preferably about 25 μm or more. The preferred ranges of the thickness of the barrier layer 52 include about 10 to 85 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 52 is made of an aluminum alloy foil, the above-mentioned range is particularly preferable. From the viewpoint of imparting high formability and high rigidity to the exterior film 50, the thickness of the barrier layer 52 is preferably about 35 μm or more, more preferably about 45 μm or more, even more preferably about 50 μm or more, and even more preferably about 55 μm or more, and is preferably about 200 μm or less, more preferably about 85 μm or less, even more preferably about 75 μm or less, and even more preferably about 70 μm or less. Preferable ranges are about 35 to 200 μm, about 35 to 85 μm, about 35 to 75 μm, about 35 to 70 μm, about 45 to 200 μm, about 45 to 85 μm, about 45 to 75 μm, about 45 to 70 μm, about 50 to 200 μm, about 50 to 85 μm, about 50 to 75 μm, about 50 to 70 μm, about 55 to 200 μm, about 55 to 85 μm, about 55 to 75 μm, and about 55 to 70 μm. When the exterior film 50 has high formability, deep drawing becomes easy, which can contribute to increasing the capacity of the electricity storage device. Furthermore, when the capacity of the electricity storage device is increased, the weight of the electricity storage device increases, but the rigidity of the exterior film 50 is increased, which can contribute to high sealing performance of the electricity storage device.In particular, when the barrier layer 52 is made of stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less. The thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. Preferred ranges for the thickness of the stainless steel foil include about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

[0038] In addition, when the barrier layer 52 is an aluminum foil, it is preferable that at least the surface opposite to the base layer 51 is provided with a corrosion-resistant film in order to prevent dissolution and corrosion. The barrier layer 52 may be provided with a corrosion-resistant film on both sides. Here, the corrosion-resistant film refers to a thin film that is provided with corrosion resistance (e.g., acid resistance, alkali resistance, etc.) on the barrier layer 52 by performing, for example, hydrothermal conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment such as nickel or chromium, or corrosion prevention treatment by applying a coating agent on the surface of the barrier layer 52. Specifically, the corrosion-resistant film refers to a film that improves the acid resistance of the barrier layer 52 (acid-resistant film), a film that improves the alkali resistance of the barrier layer 52 (alkali-resistant film), etc. The treatment for forming the corrosion-resistant film may be one type, or two or more types may be combined. In addition, not only one layer but also multiple layers may be formed. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the metal foil surface is dissolved by a treatment agent to form a metal compound with excellent corrosion resistance. Note that these treatments may also be included in the definition of chemical conversion treatment. In addition, when the barrier layer 52 has a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer 52.

[0039] The corrosion-resistant coating prevents delamination between the barrier layer 52 (e.g., aluminum alloy foil) and the base layer 51 during molding of the exterior film 50, prevents dissolution and corrosion of the surface of the barrier layer 52 due to hydrogen fluoride produced by a reaction between an electrolyte and moisture, and in particular prevents dissolution and corrosion of aluminum oxide present on the surface of the barrier layer 52 when the barrier layer 52 is an aluminum alloy foil, and also improves the adhesion (wettability) of the surface of the barrier layer 52, thereby preventing delamination between the base layer 51 and the barrier layer 52 during heat sealing and between the base layer 51 and the barrier layer 52 during molding.

[0040] The heat-sealable resin layer 53 is bonded to the barrier layer 52, for example, via an adhesive layer 55. The heat-sealable resin layer 53 included in the exterior film 50 is a layer that imparts heat-sealing sealability to the exterior film 50. Examples of the heat-sealable resin layer 53 include resin films made of polyester resins such as polyethylene terephthalate resins and polybutylene terephthalate resins, polyolefin resins such as polyethylene resins and polypropylene resins, or acid-modified polyolefin resins obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The thickness of the heat-sealable resin layer 53 is preferably, for example, 20 to 300 μm, and more preferably 40 to 150 μm, in terms of sealability and strength.

[0041] The exterior film 50 preferably has one or more layers having a buffer function (hereinafter referred to as "buffer layer") outside the heat-sealable resin layer 53, more preferably outside the barrier layer 52. The buffer layer may be laminated on the outside of the base material layer 51, or the base material layer 51 may also function as a buffer layer. When the exterior film 50 has multiple buffer layers, the multiple buffer layers may be adjacent to each other, or may be laminated via the base material layer 51, the barrier layer 52, etc.

[0042] The material constituting the buffer layer can be arbitrarily selected from materials having cushioning properties. The material having cushioning properties is, for example, rubber, nonwoven fabric, or foam sheet. The rubber is, for example, natural rubber, fluororubber, or silicone rubber. The rubber hardness is preferably about 20 to 90. The material constituting the nonwoven fabric is preferably a material having excellent heat resistance. When the buffer layer is made of nonwoven fabric, the lower limit of the thickness of the buffer layer is preferably 100 μm, more preferably 200 μm, and more preferably 1000 μm. When the buffer layer is made of nonwoven fabric, the upper limit of the thickness of the buffer layer is preferably 5000 μm, and more preferably 3000 μm. The thickness of the buffer layer is preferably in the range of 100 μm to 5000 μm, 100 μm to 3000 μm, 200 μm to 5000 μm, 200 μm to 3000 μm, 1000 μm to 5000 μm, or 1000 μm to 3000 μm. Among these, the thickness of the buffer layer is most preferably in the range of 1000 μm to 3000 μm.

[0043] When the buffer layer is made of rubber, the lower limit of the buffer layer thickness is preferably 1 mm, more 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, more preferably 2 mm. When the buffer layer is made of rubber, the preferred ranges of the buffer layer thickness are 1 mm to 10 mm, 1 mm to 5 mm, 1 mm to 2 mm, 0.5 mm to 10 mm, 0.5 mm to 5 mm, and 0.5 mm to 2 mm.

[0044] When the exterior film 50 has a buffer layer, the buffer layer functions as a cushion, thereby preventing the exterior film 50 from being damaged by impact when the electricity storage device 10 is dropped or by handling during production of the electricity storage device 10.

[0045] The lid body 60 shown in FIG. 4 is, for example, a rectangular parallelepiped shape, and is, for example, a resin molded product made of a resin material. The lid body 60 may be formed by, for example, cold forming the exterior film 50, or may be a metal molded product. The material constituting the lid body 60 may include at least two or more materials selected from metal oxides, carbon materials, and rubber materials. When distinguishing between a pair of lid bodies 60, the lid body 60 disposed on one side with respect to the electrode body 20 in the FB direction may be referred to as the lid body 60A, and the lid body 60 disposed on the other side may be referred to as the lid body 60B. In this embodiment, the lid body 60A and the lid body 60B have the same configuration, and therefore, when there is no particular distinction between them, they are simply referred to as the lid body 60.

[0046] The lid 60 has a first surface 61, a second surface 62, and a sealing surface 63. The first surface 61 faces the electrode body 20. The second surface 62 is the surface opposite to the first surface 61. The sealing surface 63 is connected to the first surface 61 and the second surface 62, and is joined to the heat-sealable resin layer 53 of the exterior film 50.

[0047] The seal surface 63 includes a first seal surface 63A, a second seal surface 63B, a third seal surface 63C, and a fourth seal surface 63D. The first seal surface 63A constitutes the upper surface of the lid body 60. The first seal surface 63A extends in a first direction (LR direction in this embodiment) in a front view of the lid body 60. The second seal surface 63B and the third seal surface 63C are connected to the first seal surface 63A and constitute the side surface of the lid body 60. The second seal surface 63B and the third seal surface 63C extend in a second direction (UD direction in this embodiment) intersecting the first direction in a front view of the lid body 60. In this embodiment, the first direction and the second direction are orthogonal to each other in a front view of the lid body 60. The first direction and the second direction do not have to be orthogonal to each other in a front view of the lid body 60. The fourth seal surface 63D constitutes the lower surface of the lid body 60. The fourth sealing surface 63D extends in a first direction (the LR direction in this embodiment) when the lid 60 is viewed from the front.

[0048] When the lid body 60 is plate-shaped, it is preferable that the lid body 60 has a certain degree of thickness so that deformation of the exterior body 40 is suppressed even when the power storage device 10 is arranged in a stacked manner. From another viewpoint, when the lid body 60 is plate-shaped, it is preferable that the sealing surface 63 of the lid body 60 has a certain degree of thickness so that the sealing surface 63 of the lid body 60 and the exterior film 50 can be suitably heat-sealed when forming the second sealing portion 80 described later. The minimum value of the thickness of the lid body 60 is, for example, 1.0 mm, more preferably 3.0 mm, and even more preferably 4.0 mm. The maximum value of the thickness of the lid body 60 is, for example, 20 mm, more preferably 15 mm, and even more preferably 10 mm. The maximum value of the thickness of the lid body 60 may be 20 mm or more. The preferred ranges of the thickness of the material constituting the lid body 60 are 1.0 mm to 20 mm, 1.0 mm to 15 mm, 1.0 mm to 10 mm, 3.0 mm to 20 mm, 3.0 mm to 15 mm, 3.0 mm to 10 mm, 4.0 mm to 20 mm, 4.0 mm to 15 mm, and 4.0 mm to 10 mm. In this embodiment, when the lid body 60 is expressed as a plate-like body, the embodiment in which the lid body 60 is composed only of a film defined by the [packaging terminology] standard of JIS (Japan Industrial Standards) is not included. The thickness of the lid body 60 may vary depending on the part of the lid body 60. When the thickness of the lid body 60 varies depending on the part, the thickness of the lid body 60 is the thickness of the thickest part.

[0049] The cover 60 further includes corners 64, 65, 66, and 67. The corner 64 is a boundary between the first seal surface 63A and the second seal surface 63B. The corner 65 is a boundary between the first seal surface 63A and the third seal surface 63C. The corner 66 is a boundary between the fourth seal surface 63D and the second seal surface 63B. The corner 67 is a boundary between the fourth seal surface 63D and the third seal surface 63C. The corners 64 to 67 may have a corner shape, or may be rounded by performing R processing, in other words, by forming a R surface. In this embodiment, the corners 64 to 67 are corners.

[0050] In this embodiment, the lid body 60 is made of a resin material. Here, "made of a resin material" means that, when the entire material constituting the lid body 60 is taken as 100% by mass, the content of the resin material is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. In other words, the material constituting the lid body 60 can contain materials other than the resin material in addition to the resin material.

[0051] Specific examples of the resin include thermoplastic resins such as polyester, polyolefin, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenol resin, and modified products of these resins. The resin material may be a mixture of these resins, a copolymer, or a modified product of the copolymer. Among these, the resin material is preferably a heat-sealable resin such as polyester or polyolefin, and more preferably polyolefin. When the resin material is a resin, the lid 60 may be molded by any molding method.

[0052] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyesters. Examples of copolymerized polyesters include copolymerized polyesters in which ethylene terephthalate is the main repeating unit. Specific examples of polyesters include copolymerized polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), and polyethylene (terephthalate / decane dicarboxylate). Of these, the resin material is preferably polybutylene terephthalate from the viewpoint of increasing heat resistance and pressure resistance.

[0053] Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. Among these, polypropylene is preferred as the resin material because it has excellent heat fusion properties and electrolyte resistance.

[0054] The resin as the resin material may contain a filler as necessary. Specific examples of the filler include glass beads, graphite, glass fiber, and carbon fiber. When the resin as the resin material contains the filler, the deformation resistance of the lid body 60 against temperature changes can be improved.

[0055] The melt mass flow rate of the resin material contained in the material constituting the lid body 60 is preferably within the range of 1 g / 10 min to 80 g / 10 min, and more preferably within the range of 5 g / 10 min to 60 g / 10 min. The melt mass flow rate is measured based on JIS K7210-1:2014.

[0056] In another example, the lid body 60 may be made of a metal material. Here, "made of a metal material" means that the content of the metal material is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, when the entire material constituting the lid body 60 is taken as 100% by mass. That is, the material constituting the lid body 60 may contain materials other than the metal material in addition to the metal material. The metal material constituting the lid body 60 can be selected arbitrarily. The metal material constituting the lid body 60 is, for example, aluminum, aluminum alloy, nickel, copper, or copper alloy. For example, when the electrode body 20 is a lithium ion battery, the lid body 60 connected to the positive electrode is preferably made of aluminum or an aluminum alloy. The lid body 60 connected to the negative electrode is preferably made of nickel, copper, or a copper alloy. The material constituting the lid body 60 connected to the negative electrode may be copper plated with nickel. The material constituting the lid body 60 may include recycled metal materials.

[0057] In this embodiment, the lid body 60 is formed with 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. When the electrode body 20 is wrapped in the exterior film 50, the electrode terminal 30 protrudes to the outside of the exterior body 40 through the through hole 60X formed in the lid body 60. A small gap between the through hole 60X of the lid body 60 and the electrode terminal 30 is filled with, for example, resin. In the electricity storage device 10, the position from which the electrode terminal 30 protrudes to the outside can be arbitrarily selected. For example, the electrode terminal 30 may protrude to the outside from a hole formed on any one of the six surfaces of the exterior body 40. In this case, a small gap between the exterior body 40 and the electrode terminal 30 is filled with, for example, resin. In another example, the electrode terminal 30 may protrude to the outside of the exterior body 40 from between the seal surface 63 of the lid body 60 and the exterior film 50. In this case, the through hole 60X may not be formed in the lid body 60. In the electricity storage device 10, the lid body 60 and the electrode terminal 30 are provided as separate bodies, but the lid body 60 and the electrode terminal 30 may be formed integrally. Note that, even when the electrode terminal 30 does not protrude from the edge of the exterior body 40, the lid body 60 may not be formed with the through hole 60X.

[0058] In this embodiment, with the exterior film 50 wrapped around the electrode body 20 so as to have an opening 40A, the facing surfaces of the exterior film 50 (heat-fusible resin layer 53) are heat-sealed to form the first sealing portion 70.

[0059] The first sealed portion 70 is formed by heat-sealing a portion including the first edge 50A and a portion including the second edge 50B of the exterior film 50 shown in FIG. 5. The first sealed portion 70 extends in the longitudinal direction (FB direction) of the exterior body 40. The position at which the first sealed portion 70 is formed in the exterior body 40 can be selected arbitrarily. In this embodiment, the base 70X of the first sealed portion 70 is preferably located on the side 43 at the boundary between the first surface 41 and the second surface 42 of the exterior body 40. The first surface 41 has a larger area than the second surface 42. The base 70X of the first sealed portion 70 may be located on any surface of the exterior body 40. In this embodiment, the first sealed portion 70 protrudes outward from the electrode body 20 in a plan view. The first sealed portion 70 may be folded, for example, toward the second surface 42 of the exterior body 40, or toward the first surface 41.

[0060] In this embodiment, the second sealed portion 80 is formed by heat-sealing the heat-sealable resin layer 53 of the exterior film 50 and the seal surface 63 of the lid body 60. Hereinafter, the seal strength between the heat-sealable resin layer 53 of the exterior film 50 and the seal surface 63 of the lid body 60 may be referred to as the seal strength of the second sealed portion 80. The seal strength of the second sealed portion 80 is the seal strength between the heat-sealable resin layer 53 and the lid body 60 at the long side portion of the seal surface 63, i.e., the seal surface 63 extending in the LR (width) direction in FIG. 1A.

[0061] The seal strength of the second sealing portion 80 is measured as follows. First, a cut is made in a portion of the exterior film 50 that constitutes the first surface 41 of the exterior body 40, and three strip-shaped members 41X, 41Y, and 41Z (see the two-dot chain line in FIG. 1B) arranged in the LR direction are formed. The width of the three strip-shaped members 41X, 41Y, and 41Z in the LR direction is 15 mm. The ends of the strip-shaped members 41X, 41Y, and 41Z are joined to the lid body 60 at the second sealing portion 80. The length of the lid body 60 in the LR direction is 45 mm or more. Next, the end of the strip-shaped members 41X, 41Y, and 41Z opposite to the end joined to the lid body 60 is pulled upward in the UD direction (the direction opposite to the first surface 41B) to measure the seal strength of each of the strip-shaped members 41X, 41Y, and 41Z. In this embodiment, the seal strength of the second sealing portion 80 is the average value of the seal strengths of the strip members 41X, 41Y, and 41Z. When the length of the lid body 60 in the LR direction is less than 45 mm, three strip members of an arbitrary width X mm less than 15 mm are formed, and the seal strengths of the three strip members are measured in the same manner as when the length of the lid body 60 in the LR direction is 45 mm or more. The obtained seal strengths are divided by the arbitrary width X mm and multiplied by 15 to convert them into the seal strengths of the three strip members in a width of 15 mm. The seal strength of the second sealing portion 80 is the average value of the seal strengths of the three strip members converted into a width of 15 mm. Note that the seal strength of the second sealing portion 80 in the case where the lid body 60 is divided into multiple parts including long sides and short sides is the seal strength of the long side portion of the seal surface 63 of the multiple parts.

[0062] From the viewpoint of suitably maintaining the state in which the electrode body 20 is sealed by the exterior body 40, the seal strength of the second sealing portion 80 is preferably 40N / 15mm or more, more preferably 50N / 15mm or more, more preferably 60N / 15mm or more, more preferably 70N / 15mm or more, and more preferably 85N / 15mm or more. When the seal strength of the second sealing portion 80 is 40N / 15mm or more, the state in which the electrode body 20 is sealed by the exterior body 40 is suitably maintained even if the electricity 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 85N / 15mm or more, the state in which the electrode body 20 is sealed by the exterior body 40 is suitably maintained even if the electricity storage device 10 is used for, for example, 10 years or more. The seal strength of the second sealing portion 80 is preferably 300N / 15mm or less. A preferred range of the seal strength of the second sealing portion 80 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.

[0063] The electricity storage device 10 of this embodiment is manufactured by wrapping the exterior film 50 around the electrode body 20 and the lid body 60 in a state in which the electrode body 20 and the lid body 60 are disposed on the exterior film 50. If the position of the lid body 60 relative to the exterior film 50 deviates from a specified position, at least one of the first problem and the second problem may occur.

[0064] The first problem is that the bonding area between the exterior film 50 and the lid 60 is reduced, which may result in a decrease in the seal strength of the second sealing portion 80.

[0065] The second problem is that the adhesion of the exterior film 50 to the lid 60 decreases, and a gap is formed between the sealing surface 63 of the lid 60 and the exterior film 50. For this reason, for example, holes may be formed in the corners 64 to 67 of the lid 60 when the second sealing portion 80 is formed. Furthermore, wrinkles may occur in the exterior film 50.

[0066] In this embodiment, in order to improve the positional accuracy of the lid body 60 relative to the exterior film 50, the exterior film 50 has a first mark 91 (see FIG. 5) formed so as to correspond to at least a part of the corners 64-67 of the lid body 60. In this embodiment, in order to improve the positional accuracy of the electrode body 20 relative to the exterior film 50, it is preferable to have a second mark 92 (see FIG. 5) formed so as to correspond to at least a part of the corners 20A-20D of the electrode body 20. Note that in FIG. 5, in order to easily grasp the ranges in which the first mark 91 and the second mark 92 are formed, the first mark 91 is represented by a solid line and the second mark 92 is represented by a dashed line.

[0067] The specific configuration of the first mark 91 can be arbitrarily selected as long as the position of the lid body 60 relative to the exterior film 50 can be grasped. In this embodiment, the first mark 91 is a fold formed on the exterior film 50. The first mark 91 may be a line. When the first mark 91 is a line, the line as the first mark 91 may be formed by ink. When the first mark 91 is a line, the line as the first mark 91 may be formed by coloring the surface of the exterior film 50 with a laser. The type of line can be arbitrarily selected. The line may be, for example, a solid line, a dashed line, a dashed line, or a dashed line. The first mark 91 may be a cut that does not penetrate the exterior film 50. The first mark 91 may include at least two of a fold, a line, and a cut. The cut may be continuous in the FB direction or may be formed intermittently. The surface of the exterior film 50 on which the first mark 91 is formed may be at least one of the outer surface and the inner surface of the exterior film 50 .

[0068] The specific configuration of the second mark 92 can be selected arbitrarily as long as the position of the electrode body 20 relative to the exterior film 50 can be grasped. In the present embodiment, the second mark 92 is a crease formed on the exterior film 50. The second mark 92 may be a line. When the second mark 92 is a line, the line as the second mark 92 may be formed by coloring the surface of the exterior film 50 with a laser. The type of line can be selected arbitrarily. The line may be, for example, a solid line, a dashed line, a dashed line, or a dashed line. The second mark 92 may be a cut that does not penetrate the exterior film 50. The second mark 92 may include at least two of a crease, a line, and a cut. The cut may be continuous in the FB direction or may be formed intermittently. The surface of the exterior film 50 on which the second mark 92 is formed may be at least one of the outer surface and the inner surface of the exterior film 50.

[0069] As shown in FIG. 5, the first markings 91 include marks 91A to 91E corresponding to the lid body 60A, and marks 91F to 91J corresponding to the lid body 60B.

[0070] Mark 91A is a mark corresponding to corner 67 of lid body 60A. Mark 91B is a mark corresponding to corner 66 of lid body 60A. Mark 91C is a mark corresponding to corner 65 of lid body 60A. Marks 91D and 91E are marks corresponding to corner 64 of lid body 60A.

[0071] The marks 91A to 91E extend from the third edge 50C to the fourth edge 50D of the exterior film 50. The length of the marks 91A to 91E in the FB direction can be selected arbitrarily. In this embodiment, the length of the marks 91A to 91E in the FB direction is equal to the length of the corresponding corners 64 to 67 of the lid body 60A. The length of the marks 91A to 91E in the FB direction may be longer or shorter than the length of the corresponding corners 64 to 67 of the lid body 60A. It is preferable that the marks 91A to 91E are formed at least at the ends of the corresponding corners 64 to 67 in the FB direction.

[0072] Mark 91F is a mark corresponding to corner 66 of lid body 60B. Mark 91G is a mark corresponding to corner 67 of lid body 60B. Mark 91H is a mark corresponding to corner 64 of lid body 60B. Marks 91I and 91J are mark corresponding to corner 65 of lid body 60B.

[0073] The marks 91F-91J extend from the fourth edge 50D to the third edge 50C of the exterior film 50. The length of the marks 91F-91J in the FB direction can be selected arbitrarily. In this embodiment, the length of the marks 91F-91J in the FB direction is equal to the length of the corresponding corners 64-67 of the lid body 60B. The length of the marks 91F-91J in the FB direction may be longer or shorter than the length of the corresponding corners 64-67 of the lid body 60B. It is preferable that the marks 91F-91J are formed at least at the ends of the corresponding corners 64-67 in the FB direction.

[0074] The second mark 92 has marks 92A to 92E. The mark 92A corresponds to the corner 20D of the electrode body 20. The mark 92A is connected to the marks 91A and 91F. The mark 92A does not have to be connected to at least one of the marks 91A and 91F.

[0075] The mark 92B corresponds to the corner portion 20C of the electrode body 20. The mark 92B is connected to the mark 91B and the mark 91G. The mark 92B does not have to be connected to at least one of the mark 91B and the mark 91G.

[0076] The mark 92C corresponds to the corner portion 20B of the electrode body 20. The mark 92C is connected to the mark 91C and the mark 91H. The mark 92C does not have to be connected to at least one of the mark 91C and the mark 91H.

[0077] The mark 92D and the mark 92E correspond to the corner portion 20A of the electrode body 20. The mark 92D is connected to the mark 91D and the mark 91I. The mark 92D does not have to be connected to at least one of the mark 91D and the mark 91I.

[0078] The mark 92E is connected to the mark 91E and the mark 91J. The mark 92E does not have to be connected to at least one of the mark 91E and the mark 91J.

[0079] The marks 92A to 92E extend in the FB direction. The length of the marks 92A to 92E in the FB direction can be selected arbitrarily. In this embodiment, the length of the marks 92A to 92E in the FB direction is longer than the length of the corresponding corners 20A to 20D of the electrode assembly 20. The length of the marks 92A to 92E in the FB direction may be equal to or shorter than the length of the corners 20A to 20D of the electrode assembly 20. It is preferable that the marks 92A to 92E are formed at least at the ends in the FB direction of the corresponding corners 20A to 20D.

[0080] 1A, in the case where the first sealed portion 70 is folded from the side 43 toward the second surface 42 of the exterior body 40, the marks 92D, 91D, 91I, 92C, 91C, 91H, 92A, 91A, 91F, and 92B, 91B, 91G are valley folds, and the marks 92E, 91E, 91J are mountain folds. In the case where the first sealed portion 70 is not folded, at least one of the marks 92D, 91D, 91I, and the marks 92E, 91E, 91J located on the side 43 may be omitted.

[0081] <1-2. Configuration of the crease forming device> 6 is a schematic diagram showing an example of a crease forming device 100 (hereinafter referred to as "device 100") that forms a first mark 91 and a second mark 92 as creases in an exterior film 50. The device 100 includes a female die 110, a male die 120, and an air cylinder 130.

[0082] The female mold 110 is placed on a stand 150. The female mold 110 is preferably placed on the stand 150 via, for example, a silicone rubber sheet 140. In order to favorably form folds in the exterior film 50, it is preferable that the exterior film 50 is heated while the folds are formed. For this reason, it is preferable that, for example, a rubber heater 160 is attached to the female mold 110 so that the exterior film 50 can be heated.

[0083] The male die 120 presses the exterior film 50 against the female die 110. It is preferable that a heating device such as a rubber heater (not shown) is attached to the male die 120 so as to heat the exterior film 50. By sandwiching the exterior film 50 between the female die 110 and the male die 120, a fold is formed in the exterior film 50 whose strength depends on the R-shape and tip angle of the tip of the male die 120, and the pressure, temperature, etc., when the male die 120 is pressed in.

[0084] The air cylinder 130 is connected to the male die 120. When the air cylinder 130 is driven, the male die 120 presses the exterior film 50 against the female die 110. At least one of a crease as the first mark 91 and a crease as the second mark 92 may be formed in the exterior film 50 by folding the exterior film 50.

[0085] <1-3. Method for manufacturing electricity storage device> FIG. 7 is a flowchart showing an example of a method for manufacturing the electricity storage device 10. The method for manufacturing the electricity storage device 10 includes, for example, a first step, a second step, a third step, a fourth step, a fifth step, a sixth step, a seventh step, an eighth step, and a ninth step. The first step to the ninth step are performed, for example, by a manufacturing apparatus for the electricity storage device 10. The manufacturing apparatus includes a crease forming apparatus 100. Note that the first step to the ninth step are merely names of the steps in the manufacturing method for the electricity storage device 10 for the sake of convenience, and do not necessarily refer to the order of the steps. The order of the following steps can be changed as desired.

[0086] In a first process of step S11, the manufacturing equipment joins the lid body 60 and the electrode terminal 30. By completing the first process, a pair of lid units 60Z in which the electrode terminal 30 is joined to the lid body 60 is completed.

[0087] The second process (mark forming process) of step S12 is carried out before or after the first process. In the second process, the manufacturing device forms the first mark 91 and the second mark 92 on the exterior film 50.

[0088] The third step of step S13 is performed after the first step and the second step. In the third step, the manufacturing device places the electrode body 20 on the exterior film 50. As shown in Fig. 8, in the third step, the electrode body 20 is placed on the exterior film 50 so that the corner 20D of the electrode body 20 coincides with the mark 92A and so that the corner 20C of the electrode body 20 coincides with the mark 92B.

[0089] The fourth step (lid placement step) of step S14 is performed after the third step. In the fourth step, the manufacturing apparatus places a pair of lid units 60Z on the sides of the electrode body 20, and bonds the electrode terminal 30 and the electrode body 20. As shown in FIG. 9, in the third step, the lid unit 60Z including the lid body 60A is placed on the exterior film 50 so that the corner 67 of the lid body 60A coincides with the mark 91A and the corner 66 coincides with the mark 91B. In the fourth step, the lid unit 60Z including the lid body 60B is placed on the exterior film 50 so that the corner 66 of the lid body 60B coincides with the mark 91F and the corner 67 coincides with the mark 91G. Note that the manufacturing method of the electricity storage device 10 may include a step of first bonding the electrode body 20 and the electrode terminal 30, and then bonding the lid body 60 to the electrode terminal 30 bonded to the electrode body 20, instead of the first step and the fourth step.

[0090] The fifth step (packaging step) of step S15 is performed after the fourth step. In the fifth step, the manufacturing device wraps the exterior film 50 around the electrode body 20 and the lid body 60. In the fifth step, the manufacturing device wraps the electrode body 20 and the lid body 60 with the exterior film 50 while folding the exterior film 50 along the first mark 91 and the second mark 92. In the fifth step, the manufacturing device wraps the exterior film 50 around the electrode body 20 and the lid body 60 with tension acting on the exterior film 50 while restricting the movement of the electrode body 20 and the lid body 60 by the restricting means. The restricting means is, for example, a groove into which the electrode body 20 and the lid body 60 are fitted. The restricting means may be a device that applies an external force to the electrode body 20 and the lid body 60 so that the electrode body 20 and the lid body 60 do not move. The restricting means may be a device that applies a force to the electrode body 20 and the lid body 60 in the opposite direction to the direction in which the exterior film 50 is pulled. The restricting means may include a roller that runs over the exterior film 50 while the exterior film 50 is being pulled in order to remove wrinkles in the exterior film 50 .

[0091] The sixth step of step S16 is performed after the fifth step. In the sixth step, the manufacturing equipment forms a first sealing portion (hereinafter referred to as a "temporary first sealing portion") having an unsealed portion for injecting an electrolyte solution. In the temporary first sealing portion, the heat-sealable resin layers 53 of the exterior film 50 facing each other are bonded to each other. Note that, when the electricity storage device 10 is, for example, an all-solid-state battery, the step of injecting an electrolyte solution is not necessary, and therefore, in the sixth step, the manufacturing equipment forms the first sealing portion 70.

[0092] The seventh step of step S17 is performed after the sixth step. In the seventh step, the manufacturing apparatus forms the second sealed portion 80 by heat-sealing the heat-fusible resin layer 53 of the exterior film 50 and the sealing surface 63 of the lid body 60.

[0093] The eighth step of step S18 is performed after the seventh step. In the eighth step, the manufacturing equipment injects an electrolyte solution through the unsealed portion formed in the temporary first sealed portion.

[0094] The ninth step of step S19 is performed after the eighth step. In the ninth step, the manufacturing apparatus heat-seals a portion of the temporary first sealed portion including an unsealed portion, thereby forming the first sealed portion 70. Note that, when the power storage device 10 is, for example, an all-solid-state battery, the eighth and ninth steps are omitted.

[0095] <1-4. Effects of electricity storage devices> The exterior film 50 of the electricity storage device 10 has a first mark 91 formed so as to correspond to at least some of the corners 64 to 67 of the lid body 60. Since the first mark 91 allows the lid body 60 to be positioned relative to the exterior film 50, the position of the lid body 60 relative to the exterior film 50 is highly accurate.

[0096] [2. Modifications] The above-mentioned embodiments are examples of possible forms of the electricity storage device and the method for manufacturing the electricity storage device according to the present invention, and are not intended to limit the forms. The electricity storage device and the method for manufacturing the electricity storage device according to the present invention may take forms different from those exemplified in the embodiments. One example is a form in which a part of the configuration of the embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to the embodiment. Some examples of modified embodiments are shown below. The following modified examples can be combined with each other as long as there is no technical contradiction.

[0097] <2-1> In the above embodiment, the exterior film 50 may have at least one of the marks 91A to 91J. For example, as shown in Fig. 10, the exterior film 50 may have only the first mark 91. In another example, as shown in Fig. 11, the marks 92D, 91D, and 91I, which are less necessary for forming the second sealing portion 80, may be omitted.

[0098] <2-2> In the above embodiment, at least one of the marks 91A-91J and 92A-92D may be different from the other marks in at least one of the length, type, and crease strength. Note that the crease strength may be determined by, for example, the rising angle of the exterior film 50 when the exterior film 50 with the creases is placed on a flat surface, or the degree of depression of the heat-fusible resin layer 53 at the portion where the creases are formed.

[0099] <2-3> The configuration of the apparatus 100 can be changed arbitrarily. As shown in Fig. 12, the male mold 120 may be configured to approach and move away from the female mold 110 in a direction intersecting the gravity direction XA. In the example shown in Fig. 12, the exterior film 50 is preferably fixed in position relative to the base 150 by being pressed against the base 150 by a fixture 200.

[0100] <2-4> In the above embodiment, the exterior film 50 of the electricity storage device 10 may protrude outward from at least one of the two lid bodies 60 in the FB direction. The electrode body 20 is sealed by closing the portion of the exterior film 50 that protrudes outward from the lid body 60. The portion of the exterior film 50 that protrudes outward from the lid body 60 may be folded inward so that the outer surfaces of the exterior films 50 come into contact with each other, as in a Goebel-top container, or may be folded toward any surface of the exterior body 40, as in a brick container.

[0101] <2-5> In the above embodiment, the exterior body 40 may not have one of the two lid bodies 60. In this modification, in the FB direction, in a portion of the exterior body 40 where the lid body 60 is omitted, the electrode body 20 is sealed by closing a portion of the exterior film 50 that protrudes outward beyond the electrode body 20. The portion of the exterior film 50 that protrudes outward beyond the electrode body 20 may be folded like a Goebel-top container or a brick container.

[0102] <2-6> In the above embodiment, the outer shape of the exterior body 40 can be changed as desired. The outer shape of the exterior body 40 may be a cylinder, a prism, or a cube.

[0103] 3. Working Examples The inventors of the present application conducted a first test, a second test, and a third test on the electricity storage devices of Examples 1 and 2 and Comparative Example 1. For ease of explanation, the following description will be given by assigning the same reference numerals as in the embodiment to the elements constituting the electricity storage devices of the Examples and Comparative Example that are the same as in the embodiment.

[0104] The power storage devices of Examples 1 and 2 are power storage devices of the embodiment. The specifications of the power storage devices of Examples 1 and 2 are as follows.

[0105] The exterior film 50 is a laminate (laminate film) having a base layer 51, a barrier layer 52, and a heat-sealable resin layer 53 in this order. The base layer 51 in Examples 1 and 2 is a laminate of a polyethylene terephthalate film, an adhesive layer, a stretched nylon film, and an adhesive layer laminated in this order. The polyethylene terephthalate film has a thickness of 15 μm. The stretched nylon film has a thickness of 15 μm. The adhesive layers are both made of a two-liquid urethane adhesive. The adhesive layer has a thickness of 3 μm after curing. The barrier layer 52 in Examples 1 and 2 is made of aluminum foil. The barrier layer 52 in Examples 1 and 2 has a thickness of 40 μm. The heat-sealable resin layer 53 in Examples 1 and 2 is a laminate of maleic anhydride-modified polypropylene and random polypropylene laminated in this order. The maleic anhydride-modified polypropylene has a thickness of 40 μm. The random polypropylene has a thickness of 40 μm.

[0106] The material constituting the lid body 60 is polypropylene, and it is manufactured by injection molding. The length (height) of the lid body 60 in the UD direction is 30 mm, the length (width) in the LR direction is 100 mm, and the length (thickness) in the FB direction is 5 mm. That is, the length of the sealing surface 63 of the lid body 60, in other words, the perimeter of the lid body 60, is 260 mm.

[0107] The manufacturing method of the electricity storage devices of Examples 1 and 2 is the same as the method shown in FIG. 7. However, the electricity storage devices of Examples 1 and 2 used in the first test are in a state where the sixth step shown in FIG. 7 has been completed. The electricity storage devices of Examples 1 and 2 used in the second and third tests are in a state where the seventh step shown in FIG. 7 has been completed. The exterior film 50 of Examples 1 and 2 has marks 91A, 91B, 91E, 91F, 91G, and 91J. The marks 91A, 91B, 91E, 91F, 91G, and 91J are formed using the device 100 shown in FIG. 12. The marks 91A, 91B, 91E, 91F, 91G, and 91J are folds. In Example 1, the pressing conditions of the male mold 120 against the female mold 110 in the second step are a linear pressure of 0.4 N / mm and a pressing time of 1 second. In Example 2, the pressing conditions were a set temperature of 60° C., a pressing time of 10 seconds, and a linear pressure of 1.2 N / mm. In Example 1, the marks 91A, 91B, 91E, 91F, 91G, and 91J were formed without heating the exterior film 50.

[0108] The sealing conditions for forming the temporary first sealing portion 70 in the sixth step are a set temperature of 226°C, a pressing time of 10 seconds, and a surface pressure of 0.25 MPa. The sealing conditions for forming the second sealing portion 80 in the seventh step are a set temperature of 180°C, a pressing time of 3 seconds, and a surface pressure of 0.78 MPa.

[0109] The specifications of the electricity storage device of the comparative example are similar to those of the electricity storage devices of Examples 1 and 2, except that no mark is formed on the exterior film 50. The electricity storage device of the comparative example used in the first test is in a state in which the sixth step shown in Fig. 7 has been completed. The electricity storage device of the comparative example used in the second and third tests is in a state in which the seventh step shown in Fig. 7 has been completed.

[0110] The first test was a test for measuring the circumferential length of the exterior body 40. In the first test, the length (circumferential length) of the portion of the exterior body 40 corresponding to the sealing surface 63 was measured for the electricity storage devices of Examples 1 and 2 and Comparative Example 1.

[0111] The second test was a test to check the sealing property of the exterior body 40. In the second test, for the electricity storage devices of Examples 1 and 2, and Comparative Example 1, a part of the exterior body 40 was cut open, Ageless Seal Check Spray (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was sprayed onto the inside of the exterior body 40, and after about five minutes had passed, the presence or absence of leakage of the check liquid from the second sealing portion 80 was visually checked.

[0112] The third test was a test for checking the presence or absence of wrinkles formed on the exterior body 40. In the third test, the presence or absence of wrinkles formed on the exterior body 40 of the power storage devices of Examples 1 and 2 and Comparative Example 1 was visually checked.

[0113] FIG. 13 shows the results of the first, second and third tests. In the first test, it was confirmed that in the electricity storage devices of Examples 1 and 2, the perimeter of the exterior body 40 was not significantly different from the perimeter of the lid body 60. It can be seen that in the electricity storage devices of Examples 1 and 2, the exterior film 50 is in close contact with the sealing surface 63 of the lid body 60. On the other hand, in the electricity storage device of Comparative Example 1, it was confirmed that the perimeter of the exterior body 40 was significantly longer than the perimeter of the lid body 60. It is suggested that a gap is formed between the exterior film 50 and the sealing surface 63 of the lid body 60 in the electricity storage device of Comparative Example 1.

[0114] In the second test, leakage of the check solution was not confirmed in the electricity storage devices of Examples 1 and 2. That is, it was confirmed that no gap was formed between the exterior body 40 and the lid body 60 in the electricity storage devices of Examples 1 and 2. Leakage of the check solution was confirmed in the electricity storage device of Comparative Example 1. That is, it was confirmed that a gap was formed between the exterior body 40 and the lid body 60 in the electricity storage device of Comparative Example 1.

[0115] In the third test, no wrinkles were found in the exterior body 40 in the electricity storage devices of Examples 1 and 2. That is, it was confirmed that the exterior film 50 was in close contact with the lid body 60 in the electricity storage devices of Examples 1 and 2. Wrinkles were found in the exterior body 40 in the electricity storage device of Comparative Example 1. That is, it was confirmed that the adhesion of the exterior film 50 to the lid body 60 was low in the electricity storage device of Comparative Example 1. [Explanation of symbols]

[0116] 10: Energy storage device 20: Electrode body 20A, 20B, 20C, 20D: Corner 40: Exterior body 40A: Opening 50: Exterior film 60: Lid 64~67: Corners 91: First landmark 92: 2nd landmark

Claims

1. An electrode body; An electric storage device comprising: an exterior body that seals the electrode body, The exterior body is an exterior film that wraps the electrode body so as to form an opening; A lid body that is placed on the opening, The exterior film has a first mark formed so as to correspond to at least a part of a corner of the lid. Energy storage device.

2. The first mark is at least one of a crease, a line, and a cut that does not penetrate the exterior film. The power storage device according to claim 1 .

3. The first mark is formed in a range including at least an end of the corner portion of the lid. The electricity storage device according to claim 1 or 2.

4. The exterior film has a second mark formed so as to correspond to at least a part of a corner of the electrode body. The electricity storage device according to claim 1 or 2.

5. The first mark and the second mark are connected to each other. The electricity storage device according to claim 4 .

6. An exterior film used as an exterior body of an electricity storage device, The electricity storage device includes an electrode body and a lid body, The exterior film has a first mark formed so as to correspond to at least a part of a corner of the lid. Exterior film.

7. The first mark is at least one of a crease, a line, and a cut that does not penetrate the exterior film. The exterior film according to claim 6.

8. The first mark is formed in a range including at least an end of the corner portion of the lid. The packaging film according to claim 6 or 7.

9. A second mark is formed so as to correspond to at least a part of the corner of the electrode body. The packaging film according to claim 6 or 7.

10. The first mark and the second mark are connected to each other. The exterior film according to claim 9.

11. An electrode body; and an exterior body that seals the electrode body, The exterior body is an exterior film that wraps the electrode body so as to form an opening; A lid body that is placed on the opening, the exterior film has a first mark formed so as to correspond to at least a part of a corner of the lid body, The method for manufacturing the electricity storage device includes: A mark forming step of forming the first mark on the exterior film is included. A method for manufacturing an electricity storage device.

12. a placement step, which is performed after the mark forming step, of placing the lid body on the exterior film so that a corner of the lid body and the first mark are aligned; a packaging step, which is performed after the placing step, of wrapping the electrode body and the lid body in the exterior film while folding the exterior film along the first mark. The method for producing the electricity storage device according to claim 11 .

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