Power storage device and protective member for power storage device

Abstract

To provide a power storage device with improved durability.SOLUTION: A power storage device includes an electrode body having a three dimensional shape including ridge lines, an exterior film covering at least one of the ridge lines and wrapping the electrode body, and a protective member disposed outside the electrode body along at least one of the ridge lines.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device and a protective member for the electricity storage device. [Background technology]

[0002] Patent Document 1 discloses an all-solid-state battery as an example of an electricity storage device. This all-solid-state battery includes an all-solid-state battery stack, electrode terminals, and an exterior body that seals the all-solid-state battery stack. The exterior body includes a film strip member that is wrapped around the all-solid-state battery stack to have an opening, and a lid that is placed on the opening. The electrode terminals are electrically connected to the all-solid-state battery stack. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-153504 Summary of the Invention [Problem to be solved by the invention]

[0004] In an electricity storage device such as that described in Patent Document 1, a film strip is wound around the side surface, including the ridges, of an all-solid-state battery laminate. However, such a film strip is prone to breakage at the corners and ridges of the three-dimensional shape of the all-solid-state battery laminate, reducing the durability of the electricity storage device. This is not limited to all-solid-state battery laminates, but applies generally to cases where an electrode assembly having a three-dimensional shape including corners and ridges is wrapped in an exterior film. Patent Document 1 does not take this point into consideration.

[0005] An object of the present invention is to provide an electricity storage device with improved durability. [Means for solving the problem]

[0006] The energy storage device according to a first aspect of the present invention comprises an electrode body having a three-dimensional shape including ridge portions, an exterior film that covers at least one of the ridge portions and encases the electrode body, and a protective member that is arranged on the outside of the electrode body along at least one of the ridge portions.

[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 protective member is disposed on the outside of the exterior film.

[0008] An electricity storage device according to a third aspect of the present invention is the electricity storage device according to the first or second aspect, wherein the protective member is disposed inside the exterior film.

[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 encases the electrode body so as to have an opening, and the electricity storage device further includes a lid body that is placed in the opening.

[0010] A protective member according to a sixth aspect of the present invention is a protective member for an electricity storage device, the electricity storage device comprising: an electrode body having a three-dimensional shape including ridges; and an exterior film that covers at least one of the ridges and encases the electrode body. The protective member is disposed on the outside of the electrode body along at least one of the ridges. [Effects of the Invention]

[0011] According to the present invention, an electricity storage device with improved durability is provided. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view of an electricity storage device according to a first embodiment. [Figure 2] FIG. 2 is a perspective view of the electrode body of FIG. 1. [Figure 3] 2 is a cross-sectional view showing the layer structure of an exterior film included in the electricity storage device of FIG. 1. [Figure 4] FIG. 2 is a perspective view showing a schematic configuration of a lid body. [Figure 5] FIG. 2 is a perspective view showing a schematic configuration of a protection member. [Figure 6] FIG. 10 is a perspective view of an electricity storage device according to a second embodiment. [Figure 7] FIG. 10 is a perspective view showing a partial configuration of a protection member according to a second embodiment. [Figure 8] FIG. 10 is a perspective view of an electricity storage device according to a third embodiment. [Figure 9] FIG. 11 is a perspective view of a protection member and an electrode assembly according to a third embodiment. [Figure 10] FIG. 10 is a perspective view of a protection member and an electrode assembly according to a fourth embodiment. [Figure 11] FIG. 10 is a diagram showing an example of a usage state of the power storage device. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, with reference to the drawings, an explanation will be given of an electricity storage device according to some embodiments of the present invention. Note that the same or corresponding parts in the drawings are denoted by the same reference numerals, and their explanation will not be repeated. Furthermore, the drawings do not necessarily reflect the actual dimensions of each component. Note that in the present embodiment, a numerical range indicated by "to" means "greater than or equal to" or "less than or equal to." For example, the notation 2 to 15 mm means 2 mm or more and 15 mm or less. In the numerical ranges described in stages in this embodiment, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, separately described upper and lower limits, upper and lower limits, or lower and lower limits may each be combined to form a numerical range.

[0014] [1. First embodiment] <1-1. Configuration of the power storage device> Fig. 1 is a perspective view that schematically shows an electricity storage device 10 of the first embodiment. The electricity storage device 10 includes an electrode body 20, a pair of electrode terminals 30, an exterior body 40, and protective members 90 and 91. In Fig. 1, the direction of arrow UD indicates the thickness direction of the electricity storage device 10, the direction of arrow LR indicates the width direction of the electricity storage device 10, and the direction of arrow FB indicates the depth direction of the electricity storage device 10. The directions indicated by the arrows UD, LR, and FB are the same in the subsequent figures.

[0015] [Electrode body] FIG. 2 is a side view schematically illustrating the configuration of the electrode assembly 20. The electrode assembly 20 includes electrodes (positive and negative electrodes) constituting a storage battery 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, as well as a separator. In this embodiment, the electrode assembly 20 has a substantially rectangular parallelepiped shape. Note that the term "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 portion of its outer surface. However, the electrode assembly 20 may have a three-dimensional shape including multiple corners, such as a substantially polygonal prism, or may have a substantially cylindrical shape.

[0016] As shown in FIG. 2 , in this embodiment, the electrode body 20 has a front surface 21, a back surface 22, an upper surface 23, a lower surface 24, a first side surface 25, and a second side surface 26. The upper surface 23 and the lower surface 24 correspond to the upper and lower surfaces, respectively, of the laminated structure of the electrode body 20. The front surface 21, the back surface 22, the first side surface 25, and the second side surface 26 are imaginary surfaces when the electrode body 20 is viewed as a substantially rectangular parallelepiped, based on the upper surface 23 and the lower surface 24. The front surface 21 faces one of the lid bodies 60. The back surface 22 faces the other lid body 60. In this embodiment, the upper surface 23 constitutes a first surface 41 of the exterior body 40, which will be described later. In this embodiment, the lower surface 24 constitutes a third surface 43 of the exterior body 40, which will be described later. In this embodiment, the first side surface 25 constitutes a second surface 42 of the exterior body 40, which will be described later. The second side surface 26 constitutes a fourth surface 44 of the exterior body 40, which will be described later. However, each of the surfaces 23 to 26 of the electrode body 20 may constitute any of the first to fourth surfaces 41 to 44 of the exterior body 40. The electrode body 20 has ridge portions 20A, 20B, 20C, and 20D. The ridge portion 20A is formed at the boundary between the upper surface 23 and the first side surface 25. The ridge portion 20B is formed at the boundary between the upper surface 23 and the second side surface 26. The ridge portion 20C is formed at the boundary between the first side surface 25 and the lower surface 24. The ridge portion 20D is formed at the boundary between the second side surface 26 and the lower surface 24. In other words, a ridge portion refers to the boundary between two surfaces that intersect with each other. The ends of each of the ridge portions 20A to 20D form corners 230 that correspond to the vertices of a substantially rectangular parallelepiped. The outermost layer of the electrode body 20 does not necessarily have to be an electrode, but may be, for example, a protective tape or a separator.

[0017] [Exterior body] The exterior body 40 seals the electrode body 20. The exterior body 40 includes an exterior film 50 and a pair of lids 60. The exterior film 50 wraps the electrode body 20 so as to form a pair of openings 40A. In the present embodiment, the exterior film 50 is wrapped around the electrode body 20 so as to form a pair of openings 40A. However, wrapping the electrode body 20 with the exterior film 50 is not limited to wrapping the exterior film 50, and the electrode body 20 may be placed inside the exterior film 50 that has been pre-formed into a cylindrical shape. In this way, the exterior film 50 covers the front surface 21, back surface 22, top surface 23, bottom surface 24, first side surface 25, second side surface 26, ridge portions 20A to 20D, and corner portions 230 of the electrode body 20, and first surfaces 41 to 44, which will be described later, are formed in the exterior body 40. The exterior film 50 has a protruding portion 50X that protrudes outward from the portion enclosing the electrode body 20 when the exterior film 50 encases the electrode body 20. The pair of lid bodies 60 are respectively disposed on the sides of the electrode body 20 so as to close the pair of openings 40A.

[0018] For example, there is a method of forming a storage portion (recess) in the exterior film 50 through cold forming to store the electrode assembly 20. However, it is not necessarily easy to form a deep storage portion using this method. Attempting to form a deep storage portion (recess) through cold forming (for example, a forming depth of 15 mm) increases the likelihood of pinholes or cracks occurring in the exterior film 50, resulting in a decrease in battery performance. On the other hand, in this embodiment, the exterior body 40 seals the electrode assembly 20 by wrapping the exterior film 50 around the electrode assembly 20, so that the electrode assembly 20 can be easily sealed regardless of the thickness of the electrode assembly 20. Note that in order to reduce the dead space between the electrode assembly 20 and the exterior film 50 to improve the volumetric energy density of the electricity storage device 10 and to improve cooling efficiency, it is preferable that the exterior film 50 be wrapped so as to come into contact with the outer surface of the electrode assembly 20. Furthermore, in all-solid-state batteries, it is necessary to apply high pressure uniformly from the outer surface of the battery in order to exert battery performance, and therefore it is necessary to eliminate the space between the electrode body 20 and the exterior film 50. Therefore, it is preferable that the exterior film 50 is wrapped around the electrode body 20 so as to contact the outer surface of the electrode body 20.

[0019] [Exterior film] FIG. 3 is a cross-sectional view showing the layer structure of the exterior film 50. As shown in FIG. 3, the exterior film 50 is a laminate (laminate film) having, for example, a base material 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, it may not include the barrier layer 52. In other words, the exterior film 50 only needs to be made of a flexible and easily bendable material, and may be made of, for example, a resin film. Note that the exterior film 50 is preferably heat-sealable.

[0020] The substrate layer 51 included in the exterior film 50 is a layer that imparts heat resistance to the exterior film 50 and prevents pinholes from forming during processing or distribution. The substrate layer 51 is composed of, for example, at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer. For example, by including at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer in the substrate layer 51, the barrier layer 52 can be protected during processing of the exterior film 50, and breakage of the exterior film 50 can be prevented. Furthermore, 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, from the viewpoint of excellent puncture strength or impact strength, the stretched polyester resin layer is more preferably a biaxially stretched polyethylene terephthalate (PET) film, and the stretched polyamide resin layer is more preferably a biaxially stretched nylon (ONy) film. The substrate layer 51 may be composed of both a stretched polyester resin layer and a stretched polyamide resin layer. From the viewpoint of film strength, the thickness of the base layer 51 is preferably, for example, 5 to 300 μm, and more preferably 20 to 150 μm.

[0021] The barrier layer 52 is a layer that prevents at least moisture from penetrating. 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 foils, vapor-deposited films, and resin layers with barrier properties. Vapor-deposited films include metal vapor-deposited films, inorganic oxide vapor-deposited films, and carbon-containing inorganic oxide vapor-deposited films. Resin layers include fluorine-containing resins such as polyvinylidene chloride, polymers based on chlorotrifluoroethylene (CTFE), polymers based on tetrafluoroethylene (TFE), polymers having fluoroalkyl groups, and polymers based on fluoroalkyl units, as well as ethylene-vinyl alcohol copolymers. Other examples of the barrier layer 52 include resin films having at least one of these vapor-deposited films and resin layers. The barrier layer 52 may be formed of multiple layers. The barrier layer 52 preferably 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 metal material contains at least one of an aluminum alloy foil and a stainless steel foil.

[0022] In the barrier layer 52, the layer made of the aforementioned metallic material may contain recycled metallic material. Examples of recycled metallic material include recycled aluminum alloy, stainless steel, titanium steel, and steel plate. These recycled materials can be obtained by known methods. Recycled aluminum alloy material can be obtained, for example, by the manufacturing method described in International Publication No. 2022 / 092231. The barrier layer 52 may be made solely of recycled material, or may be made of a mixture of recycled and virgin material. Note that recycled metallic material refers to metallic material that has been made reusable by collecting, isolating, and refining various products used in the market or waste from manufacturing processes. Furthermore, virgin metallic material refers to new metallic material refined from natural metallic resources (raw materials) and is not recycled material.

[0023] 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, an aluminum alloy foil containing iron is preferable. 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 setting the iron content to 0.1% by mass or more, an exterior film 50 with better formability can be obtained. By setting the iron content to 9.0% by mass or less, an exterior film 50 with better flexibility can be obtained. Examples of soft aluminum alloy foils 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, and the like may also be added as needed. Softening can be achieved by annealing or other methods. From the perspective of improving the mechanical strength of the exterior film 50, the aluminum alloy foil is preferably a hard aluminum alloy foil made of, for example, a work-hardened aluminum alloy. Examples of hard aluminum alloy foils 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.

[0024] Examples of stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. Furthermore, from the viewpoint of providing an exterior film 50 with excellent formability, the stainless steel foil is preferably made of austenitic stainless steel.

[0025] Specific examples of austenitic stainless steels that can be used to form the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

[0026] In the case of a metal foil, the thickness of the barrier layer 52 should be sufficient to at least function as a barrier layer that prevents moisture penetration, 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 9.0 μm or more, more preferably about 20 μm or more, and more preferably about 25 μm or more. Preferred ranges for the thickness of the barrier layer 52 include about 9.0 to 85 μm, about 9.0 to 50 μm, about 9.0 to 40 μm, about 9.0 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 aluminum alloy foil, the above-mentioned ranges are particularly preferred. 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. Preferred ranges are approximately 35 to 200 μm, approximately 35 to 85 μm, approximately 35 to 75 μm, approximately 35 to 70 μm, approximately 45 to 200 μm, approximately 45 to 85 μm, approximately 45 to 75 μm, approximately 45 to 70 μm, approximately 50 to 200 μm, approximately 50 to 85 μm, approximately 50 to 75 μm, approximately 50 to 70 μm, approximately 55 to 200 μm, approximately 55 to 85 μm, approximately 55 to 75 μm, and approximately 55 to 70 μm. The high formability of the exterior film 50 facilitates deep drawing, which can contribute to increasing the capacity of the electricity storage device. Furthermore, while increasing the capacity of the electricity storage device increases the weight of the electricity storage device, increasing the rigidity of the exterior film 50 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.

[0027] Furthermore, when the barrier layer 52 is a metal foil, it is preferable that a corrosion-resistant coating be provided on at least the surface opposite the substrate layer 51 to prevent dissolution and corrosion. The barrier layer 52 may be provided with a corrosion-resistant coating on both sides. Here, the corrosion-resistant coating refers to a thin film that is provided with corrosion resistance (e.g., acid resistance, alkali resistance, etc.) by performing, for example, a hydrothermal conversion treatment such as boehmite treatment, a chemical conversion treatment, anodizing treatment, a plating treatment using nickel or chromium, or a corrosion prevention treatment such as applying a coating agent on the surface of the barrier layer 52. Specifically, the corrosion-resistant coating refers to a coating that improves the acid resistance of the barrier layer 52 (acid-resistant coating), a coating that improves the alkali resistance of the barrier layer 52 (alkali-resistant coating), or the like. The corrosion-resistant coating may be formed by one type of treatment or a combination of two or more types. Furthermore, the barrier layer 52 may be formed not only as a single layer but also as a multi-layer. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the surface of the metal foil is dissolved using 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. Furthermore, if the barrier layer 52 has a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer 52.

[0028] 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 water, and particularly 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.

[0029] The heat-sealable resin layer 53 is bonded to the barrier layer 52 via, for example, an adhesive layer 55. The heat-sealable resin layer 53 included in the exterior film 50 is a layer that provides heat-sealing properties 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, cyclic polyolefin resins, or acid-modified polyolefin resins obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. From the viewpoints of sealability and strength, the thickness of the heat-sealable resin layer 53 is preferably, for example, 20 to 300 μm, and more preferably 40 to 150 μm.

[0030] The exterior film 50 preferably has one or more layers with 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 with the base material layer 51, the barrier layer 52, or the like interposed therebetween.

[0031] The material constituting the buffer layer can be arbitrarily selected from materials having cushioning properties. Examples of the material having cushioning properties include rubber, nonwoven fabric, and foam sheet. Examples of rubber include natural rubber, fluororubber, and 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 even 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 even 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, and most preferably in the range of 1000 μm to 3000 μm.

[0032] When the buffer layer is made of rubber, the lower limit of the buffer layer thickness is preferably 0.5 mm. When the buffer layer is made of rubber, the upper limit of the buffer layer thickness is preferably 10 mm, more preferably 5 mm, and even more preferably 2 mm. When the buffer layer is made of rubber, the preferred range of the buffer layer thickness is 0.5 mm to 10 mm, 0.5 mm to 5 mm, or 0.5 mm to 2 mm.

[0033] 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 energy storage device 10 is dropped or by handling during the manufacture of the energy storage device 10.

[0034] In this embodiment, with the exterior film 50 wrapped around the electrode body 20 and the lid body 60, the facing surfaces (heat-fusible resin layers 53) of the exterior film 50 are heat-sealed to form the first sealed portion 70 (see FIG. 1 ). In this embodiment, the first sealed portion 70 extends in the longitudinal direction (FB direction) of the exterior body 40. The position on the exterior body 40 where the first sealed portion 70 is formed can be selected arbitrarily. In this embodiment, the base 70X of the first sealed portion 70 is located on the side 45 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 is folded, for example, toward the second surface 42 of the exterior body 40. In a plan view, the first sealing portion 70 may protrude outward beyond the electrode body 20, or may be folded toward the first surface 41. In the exterior body 40, the surface facing the first surface 41 is the third surface 43, and the surface facing the second surface is the fourth surface 44. As described above, the first surface 41 to the fourth surface 44 are surfaces corresponding to the upper surface 23, first side surface 25, lower surface 24, and second side surface 26 of the electrode body, respectively.

[0035] [Lid] FIG. 4 is a perspective view showing a schematic configuration of the lid body 60. The lid body 60 is a member arranged to close the opening 40A, and is, for example, a plate-like member having a polygonal shape when viewed from the FB direction of the electricity storage device 10. The lid body 60 is made of, for example, resin. The lid body 60 may be formed by, for example, cold forming the exterior film 50. Alternatively, the lid body 60 may be a metal molded product. Furthermore, the material constituting the lid body 60 may contain at least one of metal, metal oxide, carbon fiber reinforced plastic, and rubber.

[0036] The lid body 60 has a first surface 61, a second surface 62, and a lid seal portion 63. The first surface 61 faces the electrode body 20. The second surface 62 is the surface opposite to the first surface 61. The lid seal portion 63 is connected to the first surface 61 and the second surface 62, and is heat-sealed to the heat-fusible resin layer 53 of the exterior film 50 to form a second sealing portion 80.

[0037] The lid seal portion 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 forms the upper surface of the lid body 60. The first seal surface 63A extends in a first direction (the LR direction in this embodiment) when viewed from the front of the lid body 60. In this embodiment, a second surface 62, which is the surface facing outward from the electricity storage device 10, is defined as the front surface 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 form side surfaces of the lid body 60. The second seal surface 63B and the third seal surface 63C extend in a second direction (the UD direction in this embodiment) that intersects with the first direction when viewed from the front of the lid body 60. In this embodiment, the first direction and the second direction are perpendicular to each other when viewed from the front of the lid body 60. The first direction and the second direction do not have to be perpendicular to each other in a front view of the lid 60. The fourth sealing surface 63D forms the lower surface of the lid 60. The fourth sealing surface 63D extends in the first direction (the LR direction in this embodiment) in a front view of the lid 60.

[0038] When the lid body 60 is plate-shaped, it is preferable that the lid body 60 has a certain thickness so that deformation of the exterior body 40 is suppressed even when the electricity storage device 10 is placed on top of it. From another perspective, when the lid body 60 is plate-shaped, it is preferable that the lid seal portion 63 of the lid body 60 has a certain thickness so that the lid seal portion 63 of the lid body 60 and the exterior film 50 can be suitably heat-sealed when forming the second sealing portion 80. The minimum 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 thickness of the lid body 60 is, for example, 20 mm, more preferably 15 mm, and even more preferably 12 mm. The preferred ranges for 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 12 mm, 3.0 mm to 20 mm, 3.0 mm to 15 mm, 3.0 mm to 12 mm, 4.0 mm to 20 mm, 4.0 mm to 15 mm, and 4.0 mm to 12 mm. In this embodiment, when the lid body 60 is described as being plate-shaped, this does not include an embodiment in which the lid body 60 is composed solely of a film defined by the JIS (Japanese Industrial Standards) "Packaging Terminology" standard. The thickness of the lid body 60 may vary depending on the region of the lid body 60. When the thickness of the lid body 60 varies depending on the region, the thickness of the lid body 60 is the thickness of the thickest portion.

[0039] The lid seal portion 63 further includes boundaries 64, 65, 66, and 67. The boundary 64 is the boundary between the first seal surface 63A and the second seal surface 63B. The boundary 65 is the boundary between the first seal surface 63A and the third seal surface 63C. The boundary 66 is the boundary between the fourth seal surface 63D and the second seal surface 63B. The boundary 67 is the boundary between the fourth seal surface 63D and the third seal surface 63C. The shapes of the boundaries 64 to 67 may be angular, or may be rounded by applying a rounding process. In this embodiment, the boundaries 64 to 67 are angular.

[0040] From the viewpoint of appropriately heat-sealing the lid 60 and the exterior film 50 together, it is preferable that the material constituting the lid 60 and the material constituting the heat-sealable resin layer 53 of the exterior film 50 are mainly made of the same material. In this embodiment, the material constituting the lid 60 and the material constituting the heat-sealable resin layer 53 are mainly made of polypropylene. Note that the "main material" refers to a material that accounts for 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 total mass of the materials contained in the constituent elements is taken as 100% by mass.

[0041] In this embodiment, the lid body 60 has a through hole 60X formed therein, into which an electrode terminal 30 (described later) is inserted. The through hole 60X penetrates the first surface 61 and the second surface 62. When the electrode body 20 is stored, the electrode terminal 30 passes through the through hole 60X formed in the lid body 60 and protrudes to the outside of the exterior body 40. A small gap between the through hole 60X of the lid body 60 and the electrode terminal 30 is filled with, for example, resin. Note that, in the energy storage device 10, the position from which the electrode terminal 30 protrudes to the outside can be selected arbitrarily. For example, the electrode terminal 30 may protrude to the outside from a hole formed in 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 the energy storage device 10, the lid body 60 and the electrode terminal 30 are provided as separate bodies; however, the lid body 60 and the electrode terminal 30 may be integrally formed. If the electrode terminals 30 do not protrude from the edge of the exterior body 40, the lid body 60 does not need to have the through-holes 60X formed therein.

[0042] [Electrode terminal] Referring again to FIG. 1 , the electricity storage device 10 according to this embodiment includes a pair of electrode terminals 30. The electrode terminals 30 are metal terminals used for inputting and outputting electric power to and from the electrode body 20. One end of the electrode terminal 30 is electrically connected to the electrode body 20 (positive electrode or negative electrode). The other end of the electrode terminal 30 protrudes outward from, for example, an edge of the exterior body 40. Note that the electrode terminals 30 may be any type as long as they are capable of inputting and outputting electric power to and from the electrode body 20, and may not, for example, protrude from the exterior body 40. When a lid body 60, which will be described later, is made of, for example, metal, the lid body 60 may also function as the electrode terminals 30. In this case, the lid body 60, which functions as an electrode terminal, may or may not protrude from the exterior body 40.

[0043] 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 current collecting tab which is the positive electrode is usually made of aluminum, etc., and the electrode terminal 30 connected to the current collecting tab 210 which is the negative electrode is usually made of copper, nickel, etc.

[0044] [Protective material] 1 again, the electricity storage device 10 further includes a protective member 90 and a protective member 91. The protective member 90 and the protective member 91 are arranged on the outside of the corners 230 and the ridges 20A to 20D of the electrode assembly 20 so as to cover the corners 230 and the ridges 20A to 20D, respectively. In the first embodiment, the protective member 90 and the protective member 91 are arranged on the outside of the exterior assembly 40, and are joined to the outermost layer of the exterior film 50 or the lid 60.

[0045] FIG. 5 is a perspective view showing the configuration of the protective member 90. The protective member 90 is a member disposed on the outside of the ridge portions 20B to 20D, including the corner portions 230, of the electrode assembly 20. The protective member 90 extends in the FB direction and has an L-shape when viewed from the FB direction. The protective member 90 has a first surface portion 900 and a second surface portion 901 intersecting with the first surface portion 900. As a result, in this embodiment, one of the three protective members 90 is disposed so as to straddle the second surface 42 and the third surface 43 of the exterior body 40, another protective member 90 is disposed so as to straddle the third surface 43 and the fourth surface 44, and yet another protective member 90 is disposed so as to straddle the first surface 41 and the fourth surface 44. As a result, the protective members 90 strengthen the portions of the exterior body 40 corresponding to the ridge portions 20B to 20C of the electrode assembly 20. Before being placed on the exterior body 40, the protective member 90 may be a simple plate-like member that does not have an L-shape, and after being joined to the exterior body 40, it may have the shape shown in Figure 5.

[0046] In this embodiment, the protective member 91 is a member disposed on the outside of the ridge portion 20A of the electrode assembly 20. The protective member 91 extends in the FB direction and has a flat plate shape when viewed from the UD direction. Like the protective member 90, the protective member 91 is also bonded to the outermost layer of the exterior film 50. The protective member 91 is preferably disposed on the outside of the ridge portion 20A and on the base 70X of the first sealing portion 70. Because the protruding portion 50X is movable relative to other portions of the exterior body 40, material fatigue is likely to occur in the protruding portion 50X, particularly in a portion including the base 70X of the first sealing portion 70. In a portion of the exterior film 50 where material fatigue occurs, the barrier layer 52, the base material layer 51, and the thermally adhesive resin layer 53 may peel off, causing cracks and damaging the exterior film 50. In a typical example, the electricity storage device 10 may be moved to any location while the protruding portion 50X (first sealing portion 70) is held. In such a case, because the protruding portion 50X moves relative to other portions of the exterior body 40, a portion of the exterior film 50 including the base of the protruding portion 50X, in other words, a portion including the base 70X of the first sealing portion 70, may be damaged, resulting in a decrease in the sealing performance of the electricity storage device 10. By disposing the protective member 91 on the base 70X of the first sealing portion 70, the movement of the protruding portion 50X is suppressed and the periphery of the base 70X can be reinforced. Note that in the example of FIG. 1 , the protective member 91 is disposed on the surface 41 of the exterior body 40. However, in addition to or instead of this, the protective member 91 may also be disposed on the second surface 42 of the exterior body 40. Alternatively, the first surface 900 and the second surface 901 of the protective member 90 may be disposed outside the ridge portion 20A so as to be aligned with the second surface 42 of the exterior body 40 and the underside of the protruding portion 50X, respectively. Furthermore, with the overhanging portion 50X folded toward the first surface 41, the protective member 90 may be disposed outside the ridge portion 20A so as to straddle the base 70X of the overhanging portion 50X (first sealing portion 70) folded from the second surface 42. Furthermore, with the overhanging portion 50X folded toward the second surface 42, the protective member 90 may be disposed outside the ridge portion 20A so as to straddle the base 70X of the overhanging portion 50X (first sealing portion 70) folded from the first surface 41.

[0047] The material forming the protective member 90 and the protective member 91 may contain at least one of resin, metal, metal oxide, carbon material (such as carbon fiber reinforced plastic), and rubber material. Among these, a material having cushioning properties is preferable, and examples of such materials include the same materials as those forming the buffer layer of the exterior film 50. Furthermore, the material forming the protective member 90 and the protective member 91 is preferably an elastically deformable material. In the electricity storage device 10, the internal pressure of the electricity storage device 10 may increase due to volume changes of the positive electrode active material and the negative electrode active material of the electrode assembly 20 accompanying charging and discharging, as well as gas generation. When the internal pressure of the electricity storage device 10 increases, the exterior body 40 may expand, and the exterior film 50 may stretch. Furthermore, when vacuuming is performed in the manufacturing process of the electricity storage device 10, the exterior body 40 may shrink. When the protective members 90 and 91 are made of an elastically deformable material, the protective members 90 and 91 can deform in response to the expansion and contraction of the exterior body 40 and are less likely to separate from the exterior film 50, further enhancing the effects described below. Furthermore, when the electrode body 20 contains an electrolyte, the surfaces of the protective members 90 and 91 are preferably made of a material that is resistant to the electrolyte.

[0048] On the other hand, when the protective members 90 and 91 are formed from a material with relatively low stretching and deformability, the protective members 90 and 91 have the additional effect of suppressing the expansion and contraction deformation of the exterior body 40. Specifically, the protective members 90 and 91, which have relatively low stretching and deformability, are present on the outside of the exterior film 50, thereby limiting the expansion of the exterior body 40. Furthermore, when the protective members 90 and 91 are at least partially joined to the exterior film 50, they reduce the stretchability of the exterior film 50 in that portion, thereby limiting the contraction of the exterior body 40.

[0049] There is no particular limitation on the method for joining the protective members 90 and 91 to the exterior film 50. Examples include a method of interposing an adhesive between the protective members 90 and 91 and the exterior body 40, a method of fusing the protective members 90 and 91 and the exterior body 40 with a heat-sealing resin, a method of interposing a tape having adhesive layers on both sides between the protective members 90 and 91 and the exterior body 40, and a method of forming at least one of the protective members 90 and 91 into a tape having an adhesive layer on one side and attaching this tape along the ridgeline of the electricity storage device.

[0050] <1-2. Actions and Effects of Electricity Storage Devices> The ridge lines 20A to 20D and corners 230 of the electrode body 20 have shapes that are sharper than other parts of the electrode body 20, and when an impact is applied to the electricity storage device 10, they come into contact with the exterior film 50 and are likely to damage the exterior film 50. In the electricity storage device 10, the protective members 90 and 91 cover the parts of the exterior body 40 that correspond to the ridge lines 20A to 20D and corners 230 of the electrode body 20. This reinforces the exterior film 50 in the parts that correspond to the ridge lines 20A to 20D and corners 230 of the electrode body 20, even when an impact is applied to the electricity storage device 10, and prevents the exterior film 50 from being damaged by the ridge lines 20A to 20D and corners 230 of the electrode body 20. This in turn improves the durability of the electricity storage device 10.

[0051] [2. Second Embodiment] The power storage device 10A of the second embodiment differs from the first embodiment in that it includes a protective member 92 instead of the protective members 90 and 91, but other configurations are similar to those of the first embodiment. The following describes the power storage device 10A of the second embodiment, focusing on the differences from the first embodiment.

[0052] <2-1. Configuration of the energy storage device> FIG. 6 is a perspective view showing the configuration of an electricity storage device 10A of a second embodiment. As shown in FIG. 6, the electricity storage device 10A includes a protective member 92. The protective member 92 has three first parts 920, a second part 921, and two third parts 922. The first parts 920 are disposed on the outer sides of the ridge lines 20B to 20D, similar to the protective member 90. The second part 921 is disposed on the outer side of the ridge line 20A, similar to the protective member 91. The third parts 922 are disposed on the outer sides of the pair of lid bodies 60. The first part 920, the second part 921, and the third part 922 are connected to one another. Note that a through hole 92X may be formed in the third part 922 to expose the tip of the electrode terminal 30. The third part 922 may be configured to cover only the peripheral edge of the lid body 60.

[0053] The first parts 920 each extend in the FB direction and have an L shape when viewed from the FB direction. Both ends of the first parts 920 in the FB direction are connected to the third parts 922.

[0054] Second part 921 extends in the FB direction and has a flat plate shape when viewed from the UD direction. Both ends of second part 921 in the FB direction are connected to third part 922. Second part 921 is preferably disposed outside ridge portion 20A and on base 70X of first sealing portion 70. The reason for this is as already described in the first embodiment.

[0055] Figure 7 is a perspective view showing the configuration of third part 922. Third part 922 has a plate-shaped wall portion 9220 that faces second surface 62 of lid 60, and a side wall portion 9221 that stands up from the periphery of wall portion 9220 and covers at least a portion of lid seal portion 63 from the outside of exterior film 50. That is, in this embodiment, third part 922 is formed in a roughly container shape. Note that, for ease of explanation, other elements that may be formed in third part 922, such as through holes and slits, are not shown in Figure 7.

[0056] The third part 922 may have the function of reinforcing the seal of the second sealing part 80 by covering the lid seal part 63 of the lid body 60, the portion of the exterior film 50 facing the lid seal part 63, and at least a portion of the second surface 62 of the lid body 60. In this case, the third part 922 is preferably formed including a material that is impermeable to gas and moisture, or including a layer that is impermeable to gas and moisture. When the lid seal part 63 and the heat-sealable resin layer 53 of the exterior film 50 are heat-sealed, if the length of the exterior film 50 is greater than the length of the lid seal part 63, sagging of the exterior film 50 may occur, and the second sealing part 80 may not be partially formed. Such poor sealing may cause at least one of gas and moisture to penetrate into the exterior body 40, or, if the electricity storage device 10 contains an electrolyte, the electrolyte may leak out of the exterior body 40. When third part 922 covers both lid seal portion 63 and exterior film 50 and reinforces the seal provided by second sealing portion 80, even if a seal defect occurs in second sealing portion 80, it is possible to prevent at least one of gas and moisture from entering exterior body 40 and electrolyte from leaking out of exterior body 40. In other words, the gap between exterior film 50 and lid body 60 can be sealed more reliably.

[0057] Furthermore, when third part 922 is formed in the shape of the container, third part 922 may be joined to exterior body 40 by interposing a curable resin between third part 922 and lid 60 (particularly, lid seal portion 63). The curable resin is a resin containing at least one of a photocurable resin, a room-temperature curable resin, a thermosetting resin, and an electron beam curable resin. Among these, it is preferable to contain at least one of a photocurable resin and a room-temperature curable resin. Photocurable resin is a resin that hardens when irradiated with light of a specific wavelength. Examples of photocurable resins include radical polymerization resins that are hardened by radicalization of a photopolymerization initiator upon irradiation with ultraviolet light and a radical chain reaction with functional groups of a monomer or oligomer, and cationic polymerization resins that are hardened by initiating a cationic polymerization reaction upon irradiation with ultraviolet light. Examples of radical polymerization resins include acrylic resins, and examples of cationic polymerization resins include epoxy resins and vinyl ethers. Examples of room-temperature curable resins include resins that are primarily made of epoxy resin, ester resin, or acrylic resin and that cure when mixed with a curing agent. Examples of thermosetting resins include phenolic resin, epoxy resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, silicone resin, polyurethane, and thermosetting polyimide. Examples of electron beam curable resins include acrylic resin. By filling the space between the lid 60 and the third part 922 with such a curable resin, even if a seal defect occurs in the second sealing portion 80, it is possible to more reliably prevent gas or moisture from entering through the seal defect and prevent the electrolyte from leaking to the outside of the power storage device 10A.

[0058] The method for connecting the first part 920 and the second part 921 to the third part 922 is not particularly limited. For example, the first part 920 and the third part 922 can be connected by forming an engaging portion on one of the first part 920 and the third part 922 and forming an engaged portion on the other, and engaging these portions. Similarly, the second part 921 and the third part 922 can be connected by forming an engaging portion on one of the second part 921 and the third part 922 and forming an engaged portion on the other, and engaging these portions. The engaging portion is, for example, a convex portion, and the engaged portion is, for example, a concave portion into which the convex portion can be fitted and fixed. Additionally or alternatively, the first part 920 and the third part 922, and the second part 921 and the third part 922, can be joined to each other with an adhesive, a tape having an adhesive layer, or fused with a heat-sealable resin. The first part 920 to the third part 922 may be connected together and then attached to the exterior body 40 that seals the electrode body 20, or may be connected at the same time as being attached to the exterior body 40 that seals the electrode body 20. The first part 920, the second part 921, and the third part 922 may also be formed integrally. In this case, the protective member 92 is preferably formed from a deformable material so that it can be attached to the exterior body 40.

[0059] First part 920 to third part 922 can be formed from the same material as protective member 90 and protective member 91. The materials forming each part may be different or the same for each part. Furthermore, the method of joining first part 920 to second part 921 to exterior film 50 is not particularly limited. For example, as with protective member 90 and protective member 91, a method of interposing an adhesive between first part 920 to second part 921 and exterior body 40, a method of fusing first part 920 to second part 921 and exterior body 40 with a heat-sealing resin, a method of interposing tape having adhesive layers on both sides between first part 920 to second part 921 and exterior body 40, a method of forming at least one of first part 920 to second part 921 into a tape having an adhesive layer on one side and attaching this along the ridge line of the electricity storage device, and the like can be given. Third part 922 can also be joined to lid 60 and exterior film 50 in the same manner as first part 920 to second part 921, in addition to or instead of the methods already described.

[0060] <2-2. Actions and Effects of Electricity Storage Devices> The power storage device 10A of the second embodiment can achieve the same effects as the power storage device 10 of the first embodiment. That is, when the first part 920 to the third part 922 are made of an elastically deformable material, the first part 920 to the third part 922 can deform in response to expansion and contraction of the exterior body 40 due to changes in the internal pressure of the power storage device 10A, and are less likely to separate from the exterior film 50. As a result, even if an impact is applied to the power storage device 10A, the exterior film 50 is reinforced in the portions corresponding to the ridge lines 20A to 20D and corners 230 of the electrode body 20, and damage to the exterior film 50 by the ridge lines 20A to 20D and corners 230 of the electrode body 20 can be suppressed. Furthermore, when the third part 922 is formed to reinforce the sealing provided by the second sealing unit 80, even if a partial unsealed portion occurs in the second sealing unit 80, that portion is covered by the third part 922. This allows the gap between the exterior film 50 and the lid 60 to be sealed more reliably.

[0061] When the first part 920 to the third part 922 are formed from a material with relatively low stretching deformability, the protective member 92 has the additional effect of suppressing the above-described stretching deformation of the exterior body 40. In the electricity storage device 10A, the internal pressure of the electricity storage device 10A may increase due to volume changes in the positive electrode active material and negative electrode active material of the electrode assembly 20 associated with charging and discharging, as well as gas generation. When the internal pressure of the electricity storage device 10A increases, the exterior body 40 may expand. The presence of the protective member 92, which has relatively low stretching deformability, on the outer side of the exterior film 50 can limit the expansion of the exterior body 40. Furthermore, when a vacuum is drawn during the manufacturing process of the electricity storage device 10A, the exterior body 40 may shrink. When the protective member 92 is at least partially joined to the exterior film 50, it reduces the stretchability of the exterior film 50 in that portion, thereby suppressing such stretching deformation of the exterior body 40.

[0062] 3. Third Embodiment The electricity storage device 10B of the third embodiment differs from the first embodiment in that it includes a protective member 93 instead of the protective members 90 and 91, and the protective member 93 is disposed inside the exterior body 40, but other configurations are the same as those of the first embodiment. The following describes the electricity storage device 10B of the third embodiment, focusing on the differences from the first embodiment.

[0063] <3-1. Configuration of the energy storage device> 8 is a perspective view showing the configuration of an electricity storage device 10B according to the third embodiment (however, the electrode terminals 30 are omitted from the illustration). In the electricity storage device 10B, a protective member 93 is disposed between the electrode assembly 20 and the exterior body 40. That is, the protective member 93 is sealed in the exterior body 40 together with the electrode assembly 20.

[0064] 9 is a perspective view showing the configuration of the electrode body 20 and protective member 93 of the electricity storage device 10B. The protective member 93 has two side wall portions 930 that face the front surface 21 and the back surface 22 of the electrode body 20, and four frame portions 931 that connect the two side wall portions 930 between them. The side wall portions 930 are plate-shaped members that are spaced apart in the FB direction. The frame portions 931 are columnar members that extend in the FB direction and are connected to the two side wall portions 930. The electrode body 20 can be placed in the space defined by the side wall portions 930 and the frame portions 931.

[0065] When the electrode body 20 is placed inside the protective member 93, the four frame portions 931 are positioned outside the ridge portions 20A to 20D of the electrode body 20, respectively, and prevent the corner portions 230 and the ridge portions 20A to 20D from contacting the exterior film 50. In other words, the frame portions 931 function as a buffer between the corner portions 230 and the ridge portions 20A to 20D and the exterior film 50. As long as the shape of the frame portions 931 can prevent the corner portions 230 and the ridge portions 20A to 20D from contacting the exterior film 50, there are no particular limitations on the shape of the frame portions 931 when viewed from the FB direction, and they may be, for example, L-shaped, rectangular, circular, semicircular, polygonal, etc. The frame portions 931 may come into contact with the exterior film 50 at the outermost positions of the protective member 93. For this reason, it is preferable that at least the portions of the frame portions 931 that may come into contact with the exterior film 50 are rounded to prevent damage to the exterior film 50.

[0066] The side wall portions 930 are arranged such that one side faces the front surface 21 of the electrode body 20 and the other side faces the back surface 22 of the electrode body 20. When the electrode body 20 is arranged inside the protective member 93, the two side wall portions 930 are respectively arranged outside the ridge portions 20A to 20D of the electrode body 20, preventing the corner portions 230 and the ridge portions 20A to 20D from contacting the exterior film 50. In other words, the side wall portions 930 function as a buffer between the corner portions 230 and the ridge portions 20A to 20D and the exterior film 50. For this reason, it is preferable that at least portions of the side wall portions 930 that may come into contact with the exterior film 50 are rounded to prevent damage to the exterior film 50. For example, the side wall portions 930 have a substantially rectangular shape when viewed from the FB direction, and it is preferable that the portions corresponding to the vertices of the rectangle are rounded.

[0067] The side wall portion 930 may be provided with a through hole (not shown) for passing the current collecting tab of the electrode body 20 through. In this case, the current collecting tab can be made to protrude from the through hole of the side wall portion 930 to the outside of the protective member 93 and further electrically connected to the electrode terminal 30. Alternatively, the current collecting tab may be provided on the electrode body 20 so as to protrude in a different direction, and protrude from between the frame portions 931 to the outside of the protective member 93.

[0068] Materials for forming the side wall portion 930 and the frame portion 931 include the same materials as those listed in the first embodiment. Among these, materials with cushioning properties are preferred, and examples of such materials include the same materials as those for forming the buffer layer of the exterior film 50. Furthermore, the materials for forming the side wall portion 930 and the frame portion 931 are preferably elastically deformable materials. When the side wall portion 930 and the frame portion 931 are formed from an elastically deformable material, the protective member 93 can deform in response to volumetric changes in the positive and negative electrode active materials of the electrode assembly 20 that occur during charging and discharging, further enhancing the effects described below. Furthermore, when the electrode assembly 20 contains an electrolyte, the surfaces of the side wall portion 930 and the frame portion 931 are preferably made from a material resistant to the electrolyte. The materials for forming the side wall portion 930 and the frame portion 931 may be different from each other or the same.

[0069] On the other hand, when the side wall portion 930 and the frame portion 931 are formed of a material with relatively low stretchability and are at least partially joined to the innermost layer of the exterior film 50, the protective member 93 has the additional effect of suppressing expansion, contraction, and deformation of the exterior body 40. In the electricity storage device 10B, the internal pressure of the electricity storage device 10B may increase due to volume changes in the positive electrode active material and negative electrode active material of the electrode body 20 associated with charging and discharging, as well as gas generation. When the internal pressure of the electricity storage device 10B increases, the exterior body 40 may expand. Furthermore, when evacuation is performed in the manufacturing process of the electricity storage device 10B, the exterior body 40 may shrink. By being at least partially joined to the exterior film 50, the protective member 93 reduces the stretchability of the exterior film 50 in that portion, thereby limiting the expansion, contraction, and deformation of the exterior body 40.

[0070] <3-2. Actions and Effects of Electricity Storage Devices> According to the electricity storage device 10B of the third embodiment, the protective member 93 functions as a buffer material that prevents contact between the ridges 20A to 20D and corners 230 of the electrode body 20 and the exterior film 50. This prevents a particularly sharp portion of the electrode body 20 from impacting the exterior film 50 and damaging the exterior film 50. Furthermore, if the protective member 93 itself is made of an elastic material or if the portion that comes into contact with the exterior film 50 is rounded, damage to the exterior film 50 can be more reliably prevented. Furthermore, the protective member 93 protects the electrode body 20 from impacts applied from outside the electricity storage device 10B. This in turn improves the durability of the electricity storage device 10B.

[0071] [4. Fourth Embodiment] The electricity storage device 10C of the fourth embodiment differs from the third embodiment in that it includes a protective member 94 instead of the protective member 93, and the protective member 94 is configured to include a lid body 60, but other configurations are similar to those of the third embodiment. The electricity storage device 10C of the fourth embodiment will be described below, focusing on the parts that differ from the third embodiment.

[0072] <4-1. Configuration of the energy storage device> FIG. 10 is a perspective view showing the configuration of an electricity storage device 10C of the fourth embodiment (however, the electrode terminals 30 are not shown). The protective member 94 has a pair of lid bodies 60 and four frame portions 940 that connect the pair of lid bodies 60 between them. The configuration of the lid bodies 60 is the same as the configuration of the lid bodies 60 of the first to third embodiments. Furthermore, each of the frame portions 940 is a columnar member that extends in the FB direction and is connected to the pair of lid bodies 60, and its configuration is the same as the frame portion 931 of the third embodiment. The electrode body 20 can be placed in the space defined by the lid bodies 60 and the frame portions 940.

[0073] <4-2. Actions and Effects of Electricity Storage Devices> The electricity storage device 10C of the fourth embodiment can achieve the same effects as the electricity storage device 10B of the third embodiment. Furthermore, the electricity storage device 10C of the fourth embodiment has the pair of lid bodies 60 also function as part of the protective member 94. This allows the protective member 94 to be configured without excessively increasing the number of parts.

[0074] [5. Modifications] The above-described embodiments are examples of possible forms of the power storage device according to the present invention, and are not intended to limit the forms. The power storage device according to the present invention may take forms different from those exemplified in the embodiments. Examples include forms in which part of the configuration of each embodiment is replaced, modified, or omitted, or forms in which a new configuration is added to each embodiment. Some examples of modified forms of each embodiment are shown below. Note that the above-described embodiments and the following modified forms can be combined with each other as long as there is no technical contradiction.

[0075] (1) In the power storage device 10A of the second embodiment, the third part 922 does not have to be formed in a substantially container shape. For example, the wall surface 9220 may have a through-hole formed therein through which the electrode terminal 30 passes. The wall surface 9220 may also be formed in a frame shape so as to cover only the peripheral edge of the second surface 62 of the lid 60. The side wall portion 9221 of the third part 922 may have a slit or the like that allows the protruding portion 50X to pass through so as not to interfere with the protruding portion 50X. Furthermore, the side wall portion 9221 may be omitted from the third part 922, and the third part 922 may have only the wall surface portion 9220.

[0076] (2) In the energy storage device 10 of the first embodiment, if the base 70X of the first sealing portion 70 is formed at another position, such as on the surface of the exterior body 40, the configuration of the protective member 91 may be appropriately changed to match the position of the base 70X or may be omitted. Similarly, in the energy storage device 10A of the second embodiment, if the base 70X of the first sealing portion 70 is formed at another position, such as on the surface of the exterior body 40, the configuration of the second part 921 may be appropriately changed to match the position of the base 70X or may be omitted.

[0077] (3) In the electricity storage devices 10, 10A to 10C of the first to fourth embodiments, the exterior film 50 may protrude outward beyond the lid body 60 in the FB direction. The portion of the exterior film 50 protruding beyond the lid body 60 may be folded like a Gabeltop pouch or a brick pouch. The portion of the exterior film 50 protruding beyond the lid body 60 may be folded so as to fit along the second surface 62 of the lid body 60.

[0078] (4) In the energy storage devices 10, 10A to 10C of the first to fourth embodiments, the external shape of the exterior body 40 can be changed arbitrarily. For example, the lid body 60 does not have to be rectangular when viewed from the FB direction, but may be another polygonal shape, a substantially circular shape, or a substantially elliptical shape. The shape of the lid body 60 may be changed, for example, according to the three-dimensional shape of the electrode body 20. The shapes of the protective members 90 to 94 may also be changed appropriately, for example, according to the three-dimensional shape of the electrode body 20. For example, the shapes of the protective member 90 and the first part 920 when viewed from the FB direction do not have to be L-shaped, but may be, for example, rectangular, circular, semicircular, polygonal, etc. Note that, for example, when the electrode body 20 is substantially cylindrical, the boundary between the axial end face of the cylinder and the side circumferential surface of the cylinder constitutes the ridge of the electrode body 20.

[0079] (5) In the electricity storage devices 10, 10A to 10C of the first to third embodiments, an adhesive film (not shown) may be bonded to the outer peripheral surface of the electrode terminal 30. Any adhesive film can be selected as long as it can bond the electrode terminal 30 made of metal to the lid 60 made of, for example, resin. The adhesive film can be, for example, 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 can be a single layer or two or more layers of these films.

[0080] (6) In the electricity storage device 10B of the third embodiment, the protective member 93 is configured as a separate member from the exterior film 50. However, a member corresponding to at least the frame portion 931 of the protective member 93 may be previously joined to the innermost layer of the exterior film 50 so that when the electrode body 20 is wrapped in the exterior film 50, the frame portion 931 comes into contact with the ridge portions 20A to 20D of the electrode body 20. This also applies to the frame portion 940 of the electricity storage device 10C of the fourth embodiment. Note that the protective member 93 of the third embodiment and the protective member 94 of the fourth embodiment may be combined with the protective member 90 of the first embodiment or the protective member 91 of the second embodiment, respectively.

[0081] (7) When the protective members 90 to 94 of the first to fourth embodiments have the function of suppressing deformation of the exterior body 40 described above, the protective members 90 to 94 may be configured to selectively suppress deformation of a specific surface of the exterior body 4 depending on the manner in which the electricity storage devices 10, 10A to 10C are used. For example, as shown in FIG. 11 , the electricity storage devices 10, 10A to 10C are arranged in a row so that the fourth surfaces 44 of the electricity storage devices 10, 10A to 10C are in contact with the cooling mechanism 200. In the electricity storage devices 10, 10A to 10C arranged as shown in FIG. 11 , the fourth surfaces 44 are in contact with the cooling mechanism 200, and the third surfaces 43 are in direct contact with the first surfaces 41 of the adjacent electricity storage devices 10, 10A to 10C or indirect contact with them via a plate-like member, a buffer material, or the like. Therefore, for example, when considering expansion as one form of deformation of the exterior body 40, in the case of the energy storage devices 10, 10A to 10C arranged as shown in FIG. 11, the first surface 41, the third surface 43, and the fourth surface 44 of the exterior body 40 are relatively resistant to expansion even when the internal pressure of the energy storage devices 10, 10A to 10C increases.

[0082] On the other hand, the second surface 42 of the exterior body 40 is not in contact with other elements of the electricity storage devices 10, 10A to 10C, and is therefore prone to expansion when the internal pressure of the electricity storage devices 10, 10A to 10C increases. For this reason, in the electricity storage devices 10, 10A, the protective members 90-92 can be configured to extend over a wider area on the second surface 42 of the exterior body 40, thereby suppressing expansion of the second surface 42. On the other hand, in the electricity storage devices 10B, 10C, the expansion of the second surface 42 can be suppressed by bonding a portion of the side wall portion 930, the frame portion 931, the frame portion 940, or the lid body 60 that is located on the back side of the second surface 42 to the innermost layer of the exterior film 5 that faces that portion. In this way, the protective members 90-94 can be configured to suppress expansion of a specific surface of the exterior body 40. The above configuration applies not only to the expansion of the exterior body 40, but also to its contraction. [Explanation of symbols]

[0083] 10, 10A, 10B, 10C: Energy storage device 20: Electrode body 20A~20D: Ridge 30: Electrode terminal 40: Exterior body 40A: Opening 50: Exterior film 60: Lid 90~94: Protective materials 230: Corner

Claims

1. an electrode body having a three-dimensional shape including a ridge portion; an exterior film that covers at least one of the ridge lines and wraps the electrode body so as to have an opening; a lid body placed on the opening; an outer protective member disposed on the outside of the exterior film along at least one of the ridge lines; The lid body is a first surface facing the electrode body; a second surface opposite the first surface; a lid seal portion that is connected to the first surface and the second surface and that forms a sealed portion by being sealed with the exterior film, the outer protective member has a third part that covers the sealing portion and at least a portion of the second surface from the outside, the third part is formed separately from the exterior film, The inner surface of the third part is in contact with the outermost layer of the exterior film, or is in contact with the outermost layer of the exterior film via a thermosetting resin. Energy storage device.

2. the electrode body has two surfaces connected via one of the ridge portions, The outer protective member further includes a first part having a first surface portion and a second surface portion connected to the first surface portion, the first surface portion and the second surface portion being configured to span the two surfaces. The electricity storage device according to claim 1 .

3. The first part is connected to the third part. The electricity storage device according to claim 2 .

4. The outer protective member further includes a plate-shaped second part. The electricity storage device according to claim 1 or 2.

5. The second part is connected to the third part. The electricity storage device according to claim 4 .

6. a first sealing portion in which opposing surfaces of the exterior film are joined together; The second part is disposed at a position that restricts movement of the first sealing portion. The electricity storage device according to claim 4 .

7. the third part has a wall surface portion facing the second surface, The wall portion is formed with a through hole for allowing the current collecting tab of the electrode body to pass therethrough. The electricity storage device according to claim 1 or 2.

8. The third part has a frame-shaped side wall portion that covers the peripheral edge of the lid body. The electricity storage device according to claim 1 or 2.

9. the third part has a wall surface portion facing the second surface, The side wall portion stands upright from the side edge of the wall surface portion. The electricity storage device according to claim 8 .

10. Further, an inner protective member is disposed inside the exterior film along at least one of the ridge lines. The electricity storage device according to claim 1 or 2.

11. The electrode body includes ridge portions spaced apart in the vertical direction, The inner protection member has frame portions that are arranged vertically apart along the vertically separated ridge portions. The electricity storage device according to claim 10.

12. The inner protection member further includes side wall portions connected to the frame portions spaced apart in the vertical direction. The electricity storage device according to claim 11.

13. The side wall portion has a rounded portion that comes into contact with the exterior film. The electricity storage device according to claim 12.

14. The material constituting the inner protective member includes at least one of a material having cushioning properties, a material that is elastically deformable, a material that is resistant to an electrolyte, and a material that is low in stretching and deforming properties. The electricity storage device according to claim 10.

15. A protective member used in an electricity storage device, The electricity storage device is an electrode body having a three-dimensional shape including a ridge portion; an exterior film that covers at least one of the ridge lines and wraps the electrode body so as to have an opening; a lid body placed on the opening; an outer protective member disposed on the outside of the exterior film along at least one of the ridge lines; The lid body is a first surface facing the electrode body; a second surface opposite the first surface; a lid seal portion that is connected to the first surface and the second surface and that forms a sealed portion by being sealed with the exterior film, the protective member has a third part that covers the sealing portion and at least a part of the second surface from the outside, the third part is formed separately from the exterior film, The inner surface of the third part is configured to be in contact with the outermost layer of the exterior film or to be in contact with the outermost layer of the exterior film via a thermosetting resin. Protective material.

16. An exterior film used in an electricity storage device, The protective member according to claim 15 is bonded to the Exterior film.

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