WO2024225485A1 - Exterior member for power storage device, power storage device, and method for manufacturing power storage device - Google Patents

Abstract

An exterior film for a power storage device comprises, in order from the outer side, at least a base material layer, a barrier layer, and a laminate provided with a heat-fusible resin layer. The barrier layer contains at least one type of recycled material composed of any one of an aluminum alloy, stainless steel, titanium steel, and a steel sheet.

Description

Exterior member for power storage device, power storage device, and method for manufacturing power storage device

The present invention relates to an exterior member for an electricity storage device, an electricity storage device including this exterior member for an electricity storage device, and a method for manufacturing this electricity storage device.

Patent Publication No. 4509242 (Patent Document 1) discloses a secondary battery as an example of an electricity storage device. In this secondary battery, an electrode body is sealed in a pouch made of a laminate film. The laminate film includes a water vapor impermeable layer as an example of a barrier layer for preventing water vapor from penetrating into the pouch. The water vapor impermeable layer is made of a metal foil such as aluminum.

Patent No. 4509242

From the perspective of protecting the global environment, it is preferable for electricity storage devices to be manufactured in an energy-saving manner. In this regard, there is still room for improvement in the above-mentioned secondary batteries.

The present invention aims to provide an exterior member for an electricity storage device that can contribute to energy conservation, an electricity storage device equipped with this exterior member for an electricity storage device, and a method for manufacturing this electricity storage device.

The exterior member for an electricity storage device according to the first aspect of the present invention is composed of a laminate having, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer, and the barrier layer contains at least one type of recycled material made of aluminum alloy, stainless steel, titanium steel, or steel plate.

The electricity storage device according to the second aspect of the present invention includes an exterior member for an electricity storage device and an electrode body packaged in the exterior member for an electricity storage device, the exterior member for an electricity storage device being composed of a laminate having, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer, and the barrier layer includes at least one type of recycled material made of any one of aluminum alloy, stainless steel, titanium steel, and steel plate.

The electric storage device according to the third aspect of the present invention is the electric storage device according to the second aspect, and includes a first sealing portion that is sealed by joining the mutually facing surfaces of the exterior member for the electric storage device with the electrode body wrapped in the exterior member for the electric storage device.

The electric storage device according to the fourth aspect of the present invention is the electric storage device according to the second or third aspect, further including a lid body that seals the electrode body together with the exterior member for the electric storage device, and a second sealing portion in which the lid body and the exterior member for the electric storage device are joined.

The electric storage device according to the fifth aspect of the present invention is an electric storage device according to any one of the second to fourth aspects, in which the exterior member for the electric storage device includes a first exterior member and a second exterior member, and at least one of the first exterior member and the second exterior member is formed with a recess for accommodating the electrode body.

The method for manufacturing an electricity storage device according to the sixth aspect of the present invention is a method for manufacturing an electricity storage device according to any one of the second to fifth aspects, and includes a step of manufacturing an exterior member for the electricity storage device that is composed of a laminate having, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer, and the barrier layer includes at least one type of recycled material made of any one of aluminum alloy, stainless steel, titanium steel, and steel plate.

The exterior member for an electricity storage device, the electricity storage device, and the method for manufacturing an electricity storage device according to the present invention can contribute to energy conservation.

FIG. 1 is a perspective view illustrating a schematic diagram of an electricity accumulation device according to a first embodiment. FIG. 1B is a cross-sectional view showing an example of a layer structure of the exterior member of FIG. 1A. FIG. 2 is a plan view illustrating a schematic diagram of the electricity storage device. FIG. 2 is a side view illustrating a schematic diagram of the electricity storage device. 13 is a side view showing a state in which a sheath member is wrapped around an electrode body during manufacture of the electricity storage device according to the first embodiment. FIG. 13 is a view showing a state in which a sheath member is wrapped around an electrode body, as viewed from below, during manufacture of the electricity storage device according to the first embodiment. FIG. FIG. 3 is a schematic diagram showing a part of the cross section taken along the line VI-VI in FIG. 2. 11A to 11C are diagrams illustrating a method of forming a second sealing portion. 5 is a flowchart showing an example of a manufacturing procedure for the electricity accumulation device according to the first embodiment. FIG. 11 is a plan view illustrating a schematic diagram of an electricity accumulation device according to a second embodiment. FIG. 2 is a side view illustrating a schematic diagram of the electricity storage device. FIG. 2 is a perspective view showing a typical cover body. 13A and 13B are diagrams showing a first example in which a lid body and an electrode terminal are integrally formed. 13A and 13B are diagrams showing a second example in which the lid and the electrode terminals are integrally formed. 13 is a flowchart showing an example of a manufacturing procedure for an electricity accumulation device according to a second embodiment. 13 is a flowchart showing an example of another manufacturing procedure for the electricity accumulation device according to the second embodiment. FIG. 11 is a side view showing a state in which an exterior member is wrapped around an electrode body in embodiment 3. 13 is a diagram showing a state in which an exterior member is wrapped around an electrode body and a lid body is attached to the exterior member, as viewed from below, in embodiment 3. FIG. 13 is a flowchart showing an example of a manufacturing procedure for an electricity accumulation device according to a third embodiment. FIG. 13 is a plan view illustrating a power storage device according to a fourth embodiment. FIG. 13 is a side view illustrating a schematic diagram of an electricity accumulation device according to a fourth embodiment. FIG. 11 is a side view showing a state in which an exterior member is wrapped around an electrode body in a modified example. FIG. 13 is a perspective view that illustrates a modified example of an electricity storage device. 13 is a perspective view showing a modified example of a cover and an electrode terminal attached to the cover. FIG. 13A to 13C are diagrams illustrating an insertion step in a manufacturing method for an electricity accumulation device according to a modified example. 13 is a perspective view showing a modified example of a cover and an electrode terminal attached to the cover. FIG. FIG. 24 is a perspective view illustrating a schematic diagram of an electricity storage device to which the lid body of FIG. 23 is attached. FIG. 13 is a front view showing a schematic diagram of a cover according to another modified example. FIG. 13 is a front view showing a schematic diagram of a cover according to still another modified example. FIG. 11 is a plan view illustrating a schematic diagram of an electricity storage device according to another modified example. FIG. 13 is a cross-sectional view of an electricity storage device according to still another modified example. 30B is a diagram showing an example of a manufacturing process for an electricity storage device according to another modified example of the electricity storage device in FIG. 30A. FIG. 30C is a perspective view of an electricity storage device manufactured through the manufacturing process of FIG. 30B. FIG. 30B is a perspective view of an electricity storage device which is yet another modified example of the electricity storage device of FIG. 30A. 13 is a side view showing a state in which a sheath member is wrapped around an electrode body during the manufacture of an electricity storage device according to another modified example. FIG. FIG. 32 is an enlarged view of a portion X in FIG. 31 . FIG. 11 is a cross-sectional view of an electricity storage device according to a modified example. FIG. 11 is a cross-sectional view of an electricity storage device according to a modified example.

Below, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are given the same reference numerals, and their description will not be repeated. Note that in this embodiment, a numerical range indicated by "~" 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 limit or lower limit value described in a certain numerical range may be replaced with the upper limit or lower limit value of another numerical range described in stages. Also, separately described upper limit and upper limit values, upper limit and lower limit values, or lower limit and lower limit values may each be combined to form a numerical range.

[1. First embodiment]
<1-1. Configuration of power storage device>
Fig. 1A is a perspective view that typically shows an electricity storage device 10 according to the first embodiment. Fig. 2 is a plan view that typically shows the electricity storage device 10. Fig. 3 is a side view that typically shows the electricity storage device 10. In each of Figs. 2 and 3, the direction of the arrow UD indicates the thickness direction of the electricity storage device 10, and the direction of the arrow LR indicates the width direction of the electricity storage device 10. Furthermore, 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 subsequent figures.

Referring to Figures 1A, 1B, 2 and 3, the electricity storage device 10 includes an electrode body 200, an exterior body 100, and a plurality (two) of electrode terminals 300. The electrode body 200 includes electrodes (positive and negative electrodes) and separators that constitute an electricity storage member such as a lithium ion battery, a capacitor, or an all-solid-state battery. The shape of the electrode body 200 is approximately a rectangular parallelepiped. Note that "approximately a rectangular parallelepiped" includes not only a perfect rectangular parallelepiped, but also a solid that can be regarded as a rectangular parallelepiped by, for example, modifying the shape of a portion of the outer surface.

The electrode terminal 300 is a metal terminal used for inputting and outputting power in the electrode body 200. One end of the electrode terminal 300 is electrically connected to an electrode (positive or negative electrode) included in the electrode body 200, and the other end protrudes outward from the edge of the exterior body 100.

The metal material constituting the electrode terminal 300 is, for example, aluminum, nickel, copper, etc. For example, if the electrode body 200 is a lithium ion battery, the electrode terminal 300 connected to the positive electrode is usually made of aluminum, etc., and the electrode terminal 300 connected to the negative electrode is usually made of copper, nickel, etc.

The exterior body 100 is composed of a film-like exterior member 101 for an electricity storage device (hereinafter referred to as "exterior member 101") shown in FIG. 1B, and seals the electrode body 200. In the electricity storage device 10 of this embodiment, the exterior member 101 is wrapped around the electrode body 200 and the open portion is sealed, thereby forming the exterior body 100.

The exterior body 100 seals the electrode body 200 by wrapping the exterior member 101 around the electrode body 200, so that the electrode body 200 can be easily sealed regardless of the thickness of the electrode body 200. In order to reduce the dead space between the electrode body 200 and the exterior member 101 in order to improve the volumetric energy density of the power storage device 10, it is preferable that the exterior member 101 is wrapped around the electrode body 200 so as to contact the outer surface of the electrode body 200. 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 exert battery performance, so it is necessary to eliminate the space between the electrode body 200 and the exterior member 101. Therefore, it is preferable that the exterior member 101 is wrapped around the electrode body 200 so as to contact the outer surface of the electrode body 200. In addition, the exterior body 100 may be configured by forming a storage portion (recess) in the exterior member 101 through cold forming and storing the electrode body 200 in the storage portion.

FIG. 1B is a cross-sectional view showing an example of the layer structure of the exterior member 101. The exterior member 101 is, for example, a laminate 101Z (laminate film) having, in this order from the outside, at least a base layer 101A, a barrier layer 101B, and a heat-sealable resin layer 101C.

The base material layer 101A included in the exterior member 101 is a layer for imparting heat resistance to the exterior member 101 and suppressing the occurrence of pinholes that may occur during processing or distribution. The base material layer 101A is composed of, for example, at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer. For example, the base material layer 101A includes at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer, so that the barrier layer 101B can be protected during processing of the exterior member 101 and breakage of the exterior member 101 can be suppressed. In addition, from the viewpoint of increasing the tensile elongation of the exterior member 101, 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 base layer 101A may be configured to include both a stretched polyester resin layer and a stretched polyamide resin layer. From the viewpoint of film strength, the thickness of the base layer 101A is preferably, for example, 5 to 300 μm, and more preferably 20 to 150 μm.

In the exterior member 101, the barrier layer 101B is a layer that at least suppresses the penetration of moisture. From the viewpoint of energy saving, the barrier layer 101B of the exterior member 101 in this embodiment contains at least one type of recycled material made of any one of aluminum alloy, stainless steel, titanium steel, and steel plate. The barrier layer 101B may be provided in multiple layers. The aluminum alloy and stainless steel can also be used as metal foil, for example. The barrier layer 101B may be composed only of recycled materials. From the viewpoint of improving the formability of the exterior member 101, the barrier layer 101B may be composed of a mixed material of recycled materials and virgin raw materials.

Recycled materials made of aluminum alloys, stainless steel, titanium steel, or steel plates can be obtained by known methods. For example, recycled aluminum alloy materials can be obtained by the manufacturing method described in WO 2022/092231.

From the viewpoint of improving the formability or conformability of the exterior member 101, 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 mass%), the iron content is preferably 0.1 to 9.0 mass%, and more preferably 0.5 to 2.0 mass%. By having an iron content of 0.1 mass% or more, an exterior material for an electricity storage device having better formability can be obtained. By having an iron content of 9.0 mass% or less, an exterior material for an electricity storage device 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 or the like. From the viewpoint of improving the mechanical strength of the exterior member 101, 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. From the viewpoint of improving the mechanical strength of the exterior member 101, the aluminum alloy foil is preferably an aluminum alloy foil containing magnesium. In the aluminum alloy foil containing magnesium (100% by mass), the magnesium content is preferably 0.2 to 5.6% by mass, and more preferably 0.2 to 3.0% by mass. Examples of aluminum alloy foils containing magnesium include aluminum alloy foils having compositions specified in JIS H4000:2017 A5005P-O, JIS H4000:2017 A5050P-O, and JIS H4000:2017 A5052P-O.

Furthermore, 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 material for an electricity storage device with excellent formability, it is preferable that the stainless steel foil is made of austenitic stainless steel.

Specific examples of austenitic stainless steels that make up the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

In the case of a metal foil, the thickness of barrier layer 101B should at least function as a barrier layer that prevents moisture from penetrating, and may be, for example, about 5 to 200 μm. The thickness of barrier layer 101B 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 barrier layer 101B is preferably about 9.0 μm or more, more preferably about 20 μm or more, and more preferably about 25 μm or more. Preferable ranges for the thickness of the barrier layer 101B 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 101B is made of an aluminum alloy foil, the above-mentioned ranges are particularly preferable. From the viewpoint of imparting high moldability and high rigidity to the exterior member 101, the thickness of the barrier layer 101B 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. The 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. By providing the exterior member 101 with high formability, deep drawing is facilitated, which can contribute to the high capacity of the electricity storage device. In addition, when the capacity of the electricity storage device is increased, the weight of the electricity storage device increases, but the rigidity of the exterior member 101 is increased, which can contribute to the high sealing property of the electricity storage device. In particular, when the barrier layer 101B 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.

In addition, when the barrier layer 101B is a metal foil, it is preferable that at least the surface opposite to the base layer 101A is provided with a corrosion-resistant film in order to prevent dissolution and corrosion. The barrier layer 101B 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 101B 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 101B. Specifically, the corrosion-resistant film means a film that improves the acid resistance of the barrier layer 101B (acid-resistant film), a film that improves the alkali resistance of the barrier layer 101B (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, it is possible to form not only one layer but also multiple layers. 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. Also, if the barrier layer 101B has a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer 101B.

The corrosion-resistant coating prevents delamination between the barrier layer 101B (e.g., aluminum alloy foil) and the base layer 101A during molding of the exterior member 101, and prevents dissolution and corrosion of the surface of the barrier layer 101B due to hydrogen fluoride produced by the reaction of the electrolyte with water, particularly when the barrier layer 101B is an aluminum alloy foil, dissolution and corrosion of aluminum oxide present on the surface of the barrier layer 101B. The corrosion-resistant coating also improves the adhesion (wettability) of the surface of the barrier layer 101B, and is effective in preventing delamination between the base layer 101A and the barrier layer 101B during heat sealing, and between the base layer 101A and the barrier layer 101B during molding of the exterior member 101.

The heat-sealable resin layer 101C included in the exterior member 101 is a layer that provides the exterior member 101 with heat-sealing sealability. Examples of the heat-sealable resin layer 101C include resin films made of polyolefin resins or acid-modified polyolefin resins obtained by graft-modifying polyolefin resins with acids such as maleic anhydride. The thickness of the heat-sealable resin layer 101C is not particularly limited as long as the heat-sealable resin layers 101C are heat-sealed to each other to function as a seal for the electrode body 200, but may be, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm.

If the heat-sealable resin layer 101C is too hard, when the rolled raw material or the exterior member 101 is bagged into the exterior body 100 by the device, it may slip at the contact point with the device and may not be transported properly. Furthermore, if the exterior member 101 is scratched by the friction, the heat-sealable resin layer 101C will be damaged. Damage to the heat-sealable resin layer 101C may reduce the heat seal strength, so it is preferable for the heat-sealable resin layer to have a moderately slippery property. For this reason, when a non-slip or less-slippery material is used as the material constituting the heat-sealable resin layer 101C, it is preferable to add a lubricant from the viewpoint of transportability.

Furthermore, from the viewpoint of contamination resistance and processability, it is preferable that the tensile modulus of the heat-sealable resin layer 101C, measured in accordance with the provisions of JIS K7161:2014, is in the range of 500 MPa or more and 1000 MPa or less. A more preferable range for the tensile modulus of the heat-sealable resin layer 101C is 500 MPa or more and 800 MPa or less, an even more preferable range is 500 MPa or more and 750 MPa or less, an even more preferable range is 500 MPa or more and 700 MPa or less, and an even more preferable range is 510 MPa or more and 700 MPa or less.

The tensile modulus of the heat-sealable resin layer 101C is 500 MPa or more, which effectively suppresses contamination of the device during molding and transportation of the exterior body 100. That is, the tensile modulus of the heat-sealable resin layer 101C is 500 MPa or more, which makes it difficult for the lubricant located on the surface of the heat-sealable resin layer 101C to be scraped off by the device, etc., and therefore the lubricant located on the surface portion of the heat-sealable resin layer 101C is difficult to transfer to the device, etc., and contamination of the device, etc. is effectively suppressed. In addition, the tensile modulus of the heat-sealable resin layer 101C is 1000 MPa or less, which provides high sealing strength by heat fusion. That is, the tensile modulus of the heat-sealable resin layer 101C is 1000 MPa or less, which makes it difficult for the heat-sealable resin layer 101C to become brittle, and therefore provides high sealing strength by heat fusion. If the tensile modulus of the heat-sealable resin layer 101C exceeds 1000 MPa, the heat-sealable resin layer 101C becomes brittle and is easily peeled off from the barrier layer 101B laminated via an adhesive layer, resulting in a decrease in seal strength, or the stretching at the folded portion during molding of the exterior body 100 may cause whitening or cracks in the stretched portion, resulting in a decrease in battery performance. In addition, if the tensile modulus of the heat-sealable resin layer 101C exceeds 1000 MPa, the extrudability decreases, which is a factor in decreasing productivity. Therefore, in the exterior member 101 of the power storage device 10 of this embodiment, by setting the tensile modulus of the heat-sealable resin layer 101C to a range of 500 to 1000 MPa, the effect of suppressing contamination of the device and the like and the effect of improving the seal strength by heat fusion are suitably exhibited. The tensile modulus of the heat-sealable resin layer 101C can be adjusted by adjusting the molecular weight, melt mass flow rate (MFR), etc. of the resin constituting the heat-sealable resin layer 101C.

In addition, when the work of butting together the sealed portions for pillow sealing when making the bag of the exterior body 100, the work of bending, etc., is called processing, the same problems as described above occur during the processing. Since the exterior member 101 is particularly susceptible to damage during processing, solving the above problems is important. By setting the tensile modulus of elasticity of the heat-sealable resin layer 101C in the range of 500 MPa or more and 1000 MPa or less, processing can be performed well.

The exterior member 101 preferably has one or more layers having a buffer function (hereinafter referred to as "buffer layers") outside the heat-sealable resin layer 101C (upper side in FIG. 1B), more preferably outside the barrier layer 101B. The buffer layer may be laminated on the outside of the base layer 101A, or the base layer 101A may also function as a buffer layer. When the exterior member 101 has multiple buffer layers, the multiple buffer layers may be adjacent to each other, or may be laminated via the base layer 101A or the barrier layer 101B, etc.

The material constituting the buffer layer can be selected from any material 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 composed 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 composed of nonwoven fabric, the upper limit of the thickness of the buffer layer is preferably 5000 μm, and even more preferably 3000 μm. The preferred range of the thickness of the buffer layer is 100 μm to 5000 μm, 100 μm to 3000 μm, 200 μm to 5000 μm, 200 μm to 3000 μm, 1000 μm to 5000 μm, or 1000 μm to 3000 μm. Among these, the most preferred range of the thickness of the buffer layer is 1000 μm to 3000 μm.

When the buffer layer is made of rubber, the lower limit of the thickness of the buffer layer is preferably 0.5 mm. When the buffer layer is made of rubber, the upper limit of the thickness of the buffer layer 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 thickness of the buffer layer is 0.5 mm to 10 mm, 0.5 mm to 5 mm, or 0.5 mm to 2 mm.

When the exterior member 101 has a buffer layer, the buffer layer functions as a cushion, preventing the exterior member 101 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.

In the exterior body 100 of this embodiment, a deep storage portion can be formed in the exterior member 101 through cold forming, which increases the weight of the electrode body 200 and increases the attack on the exterior body 100 due to impacts, etc. For this reason, in this embodiment, when the thickness of the exterior member 101 is 195 μm or less and the thickness of the barrier layer 101B is included in the range of 20 to 85 μm, it is preferable that the puncture strength when pierced from the base layer 101A side of the exterior member 101, measured by a method conforming to the provisions of JIS Z1707:1997, is 30 N or more. Preferred ranges of the puncture strength include, for example, about 30 to 45 N, about 30 to 40 N, about 35 to 45 N, and about 35 to 40 N. The puncture strength of the exterior member 101 is measured as follows.

The puncture strength from the base layer 101A side of the exterior member 101 is measured by a method conforming to the provisions of JIS Z1707:1997. Specifically, in a measurement environment of 23±2°C and relative humidity (50±5)%, a test piece is fixed with a 115mm diameter stand with a 15mm diameter opening in the center and a pressure plate, and a semicircular needle with a diameter of 1.0mm and a tip radius of 0.5mm is pierced at a speed of 50±5mm per minute, and the maximum stress until the needle penetrates is measured. Five test pieces are measured, and their average value is calculated. If there are not enough test pieces to measure five, the number that can be measured is measured, and the average value is calculated. The puncture strength measuring device used is Imada's ZP-500N (force gauge) and MX2-500N (measurement stand).

In the electric storage device 10 of this embodiment, as the electrode body 200 becomes heavier, friction between the electric storage devices 10, friction between the electric storage device 10 and surrounding members, and friction during transportation of the electric storage device 10 are likely to occur. For this reason, in this embodiment, in addition to good fixation of the ink (good printing characteristics) on the surface of the base material layer 101A side of the exterior member 101, it is preferable that the fixed ink is not easily lost. From this perspective, it is preferable that the contact angle of the surface of the base material layer 101A side of the exterior member 101 of this embodiment is 80° or less. That is, when the base material layer 101A constitutes the outermost surface of the exterior member 101, the contact angle of the surface of the base material layer 101A is 80° or less. Furthermore, when a coating layer is provided on the outside of the base material layer 101A, the contact angle of the surface of the coating layer is 80° or less. In this embodiment, the contact angle of the surface of the base layer 101A side of the exterior member 101 is 80° or less, so that the ink is not easily repelled on the surface of the base layer 101A side, the printing characteristics are excellent, and the fixed ink is not easily lost. In particular, when ink is printed by pad printing on the exterior member 101 in which a lubricant is present on the surface of the base layer 101A side to enhance formability, the ink may be repelled by the surface of the base layer 101A side, resulting in printing defects. However, even in such a case, the exterior member 101 of the power storage device 10 of this embodiment has a contact angle of 80° or less on the surface of the base layer 101A side, so that the ink is not easily repelled, and the exterior member 101 is particularly suitable as an exterior member 101 on which printing or the like is formed on the surface of the base layer 101A by pad printing.

In this embodiment, from the viewpoint of improving printability and preventing the fixed ink from disappearing, it is more preferable that the contact angle of the surface on the substrate layer 101A side is 79° or less, and even more preferable that it is 72° or less. The contact angle of the surface on the substrate layer 101A side is measured using an LSE-A210 manufactured by NIC Co., Ltd., at the contact angle of the interface between the substrate and the water droplet 5 seconds after the water droplet is applied.

In this embodiment, the contact angle of the surface on the substrate layer 101A side can be suitably set to 80° or less, for example, by subjecting the surface on the substrate layer 101A side to a corona treatment. The corona treatment can be performed by irradiating the surface on the substrate layer 101A side with a corona discharge using a commercially available corona surface treatment device. The corona treatment conditions are, for example, an irradiation output of 1 Kw or more and a speed of 10 MT/min to treat the surface on the substrate layer 101A side, thereby making it possible to reduce the contact angle of the surface on the substrate layer 101A side to 80° or less.

When printing ink on the surface of the exterior member 101, a corona treatment is performed, followed by a step of printing ink on at least a portion of the surface of the base layer 101A. The printing method is not particularly limited, but inkjet printing and pad printing are preferred when printing on the exterior member 101 after molding. In the exterior member 101 of the power storage device 10 of this embodiment, the contact angle of the surface on the base layer 101A side is set to 80° or less, so that ink can be suitably printed even by pad printing, in which ink is easily repelled by the base layer 101A, which has a lubricant on its surface. Therefore, for example, barcodes, patterns, letters, and other prints can be suitably formed on at least a portion of the surface of the base layer 101A.

FIG. 4 is a side view of the exterior member 101 wrapped around the electrode body 200 during the manufacturing process of the energy storage device 10. As shown in FIG. 4, the exterior member 101 is wrapped around the electrode body 200. In this case, the outermost layer of the electrode body 200 does not necessarily have to be an electrode, and may be, for example, a protective tape or a separator. With the exterior member 101 wrapped around the electrode body 200, the opposing surfaces (thermally adhesive resin layers) of the exterior member 101 are heat sealed to form a first sealing portion 110.

It is preferable that the root portion of the first sealing portion 110 is located on the side 135 of the exterior body 100. In this embodiment, the side 135 is formed at the boundary between the first surface 130 and the second surface 140, which has a smaller area than the first surface 130. In other words, in this embodiment, the root portion of the first sealing portion 110 can be said to be formed at the boundary between the first surface 130 and the second surface 140, and can be said to be not present on either the first surface 130 or the second surface 140. The root portion of the first sealing portion 110 may be located other than the side 135. In other words, the root portion of the first sealing portion 110 may be located on any surface, such as the first surface 130 or the second surface 140 of the exterior body 100. In the energy storage device 10, the first sealing portion 110 is bent toward the second surface 140 around the side 135. In the power storage device 10, the first sealing portion 110 contacts the second surface 140 and covers substantially the entirety of the second surface 140. Note that "substantially the entirety of the second surface 140" refers to an area that occupies 75% or more of the area of the second surface 140.

That is, in the energy storage device 10, the first sealing portion 110 is not formed on the first surface 130, which has a large area. The first surface 130 is flatter than when a sealing portion such as the first sealing portion 110 is in contact with the first surface 130. Therefore, even if another energy storage device 10 is placed on the first surface 130, the other energy storage device 10 does not tilt. As a result, according to the energy storage device 10, when multiple energy storage devices 10 are stacked, unevenness in the distribution of pressure applied to the lower energy storage device 10 can be suppressed. In other words, when multiple energy storage devices 10 are stacked to form a module, the first sealing portion 110 is not arranged on the surface (first surface 130) adjacent to the adjacent energy storage device 10. In addition, such a configuration is preferable from the viewpoint that it is necessary to apply high pressure uniformly from the outer surface of the battery in order to exhibit the battery performance in an all-solid-state battery.

Furthermore, in the energy storage device 10, the root portion of the first sealing portion 110 is on the side 135 of the exterior body 100. Therefore, according to the energy storage device 10, a wider bonding area can be secured in the first sealing portion 110 compared to when the root portion of the first sealing portion 110 is on the second surface 140 (for example, the central portion of the second surface 140 in the direction of the arrow UD). Note that the bonding area of the first sealing portion 110 does not necessarily have to be the entire area of the first sealing portion 110, and may be only a part of the first sealing portion 110, such as only the vicinity of the root portion of the first sealing portion 110.

Also, in the energy storage device 10, substantially the entire second surface 140 is covered by the first sealing portion 110. That is, in the energy storage device 10, the length of the first sealing portion 110 in the direction of the arrow UD is longer than in the case where the first sealing portion 110 covers only half or less of the area of the second surface 140 (see FIG. 3). Therefore, according to the energy storage device 10, a wide bonding area can be secured in the first sealing portion 110. Furthermore, since substantially the entire second surface 140 is covered by the first sealing portion 110, the energy storage device 10 is stable even if the energy storage device 10 is placed upright so that the second surface 140 is in contact with the mounting surface. That is, the energy storage device 10 is unlikely to tilt with respect to the mounting surface. Therefore, such a configuration is effective, for example, when forming a module by arranging multiple energy storage devices 10 side by side.

Figure 5 is a view showing from below the exterior member 101 wrapped around the electrode body 200 during the manufacture of the energy storage device 10. As shown in Figure 5, in the energy storage device 10, the direction along the edge 135 is the TD (Transverse Direction) of the exterior member 101, and the direction perpendicular to the edge 135 is the MD (Machine Direction) of the exterior member 101. In other words, the direction along the edge 135 is the direction (TD) perpendicular to the flow direction (MD) of the exterior member 101.

In the energy storage device 10, the first sealing portion 110 is folded along the edge 135, and the direction along the edge 135 is perpendicular to the flow direction of the exterior member 101. Therefore, according to the energy storage device 10, even if a crease is formed in the direction perpendicular to the flow direction of the exterior member 101, the exterior member 101 is unlikely to break, and therefore, the possibility of the first sealing portion 110 breaking due to the first sealing portion 110 being folded can be reduced.

The machine direction (MD) of the exterior member 101 corresponds to the rolling direction (RD) of the metal foil (aluminum alloy foil, etc.) of the barrier layer contained in the exterior member 101. The TD of the exterior member 101 corresponds to the TD of the metal foil. The rolling direction (RD) of the metal foil can be determined by the rolling marks.

In addition, multiple cross sections of the heat-sealable resin layer of the exterior member 101 can be observed with an electron microscope to confirm the sea-island structure, and the direction parallel to the cross section in which the average island diameter in the direction perpendicular to the thickness direction of the heat-sealable resin layer (hereinafter also referred to as the "length direction of the heat-sealable resin layer") was maximum can be determined to be the MD. When the MD of the exterior member 101 cannot be identified from the rolling grain of the metal foil, the MD can be identified by this method.

Specifically, the sea-island structure is confirmed by observing the longitudinal cross section of the heat-sealable resin layer and each cross section (a total of 10 cross sections) at an angle of 10 degrees from the direction parallel to the longitudinal cross section and perpendicular to the longitudinal cross section. Next, for each island on each cross section, the island diameter d is measured by the straight-line distance connecting both ends in the direction perpendicular to the thickness direction of the heat-sealable resin layer. Next, the average of the diameters d of the top 20 largest islands is calculated for each cross section. The direction parallel to the cross section with the largest average island diameter d is determined to be the MD.

FIG. 6 is a schematic diagram showing a portion of the cross section taken along the line VI-VI in FIG. 2. As shown in FIG. 6, the second sealing portion 120 is sealed in a state in which the exterior body 100 sandwiches the electrode terminal 300.

FIG. 7 is a diagram for explaining a method of forming the second sealing portion 120. As shown in FIG. 7, the exterior member 101 is folded, and the opposing surfaces (thermally adhesive resin layers) of the exterior member 101 are heat sealed to form the second sealing portion 120. Although omitted in FIG. 7, the electrode terminal 300 is located between the opposing surfaces of the exterior member 101. An adhesive film that adheres to both metal and resin may be placed between the electrode terminal 300 and the exterior member 101.

The adhesive film may be, for example, a one-layer or two or more-layer structure of a resin film made of polyolefin resin or acid-modified polyolefin resin obtained by graft-modifying polyolefin resin with an acid such as maleic anhydride. When the adhesive film is made of two or more layers, it is preferable to place a resin film made of polyolefin resin on the side that is joined to the exterior member 101. When the adhesive film is made of two or more layers, it is preferable to place a resin film made of acid-modified polyolefin resin obtained by graft-modifying polyolefin resin with an acid such as maleic anhydride on the side that is joined to the electrode terminal 300.

Referring again to FIG. 6, the electrode body 200 includes a plurality of electrodes 210 (positive and negative electrodes). Current collectors 215 extending from each electrode 210 are connected to an electrode terminal 300. In the electricity storage device 10, a portion of the electrode terminal 300 that is on the outside of the exterior body 100 is located at a position that is approximately half the thickness of the electricity storage device 10 in the thickness direction of the electricity storage device 10. In other words, the length L2 is approximately half the length L1. Note that "approximately half the thickness of the electricity storage device 10" means 35% to 65% of the thickness of the electricity storage device 10.

Therefore, with the energy storage device 10, the difference between the longest and shortest distances between each of the multiple electrodes 210 and the electrode terminal 300 can be made smaller than when, for example, the electrode terminal 300 is located at approximately the same position as the first surface 130 in the thickness direction of the energy storage device 10.

<1-2. Manufacturing method of electricity storage device>
Fig. 8 is a flowchart showing an example of a manufacturing procedure for the power storage device 10. The steps shown in Fig. 8 are performed, for example, by a manufacturing apparatus for the power storage device 10. Note that the manufacturing procedure for the power storage device 10 can be changed as desired.

The manufacturing equipment manufactures the exterior member 101 (step S100). The manufacturing equipment wraps the exterior member 101 around the electrode body 200 (step S110). The manufacturing equipment forms the first sealing portion 110 by heat sealing the mutually facing surfaces (thermally adhesive resin layers) of the exterior member 101 (step S120). This results in the unfinished product shown in Figures 4 and 5.

The manufacturing equipment folds the first sealing portion 110 so that the first sealing portion 110 contacts the second surface 140 (step S130). The manufacturing equipment folds the exterior member 101 with the electrode body 200 stored inside, and forms the second sealing portion 120 by heat sealing the opposing surfaces (thermally adhesive resin layers) of the exterior member 101 together (step S140). This completes the energy storage device 10.

<1-3. Features>
As described above, in the power storage device 10 according to the first embodiment, the first sealing portion 110 is folded toward the second surface 140 side having a smaller area. That is, the first sealing portion 110 does not exist on the first surface 130 having a larger area. Therefore, even if another power storage device 10 is placed on the first surface 130, the other power storage device 10 does not tilt. As a result, according to the power storage device 10, when a plurality of power storage devices 10 are stacked, unevenness in the distribution of pressure applied to the lower power storage device 10 can be suppressed. In addition, when used in an all-solid-state battery, it is necessary to apply a high pressure uniformly from the outer surface of the battery to exhibit the battery performance, so that the packaging form of the present invention is preferable. In addition, in the power storage device 10, the root portion of the first sealing portion 110 is on the side 135 of the exterior body 100. Therefore, according to the energy storage device 10, when the first sealing portion 110 is fitted onto the second surface 140, a wider joint width can be ensured in the first sealing portion 110 compared to when the base portion of the first sealing portion 110 is located on the second surface 140.

[2. Second embodiment]
In the electricity storage device 10 according to the above-described first embodiment, the second sealed portion 120 is formed by folding the exterior member 101 and heat-sealing the mutually facing surfaces of the exterior member 101. However, the shape and the method of forming the second sealed portion 120 are not limited thereto. Note that the following description will focus on the parts that are different from the first embodiment, and a description of the parts that are common to the first embodiment will be omitted.

2-1. Configuration of the Power Storage Device
Fig. 9 is a plan view typically showing an electricity storage device 10X according to the second embodiment. Fig. 10 is a side view typically showing an electricity storage device 10X. Fig. 11 is a perspective view typically showing a lid 400.

Referring to Figures 9, 10 and 11, the exterior body 100X is constructed by fitting the lid body 400 into each of the openings at both ends of the exterior member 101 wrapped around the electrode body 200. With the lid body 400 fitted, the exterior member 101 and the lid body 400 are heat sealed together to form the second sealing portion 120X.

The lid body 400 is a bottomed tray-like member having a rectangular shape in a plan view, and is formed by, for example, cold forming the exterior member 101. The lid body 400 does not necessarily have to be made of the exterior member 101, and may be a metal molded product or a resin molded product. In the energy storage device 10X, the lid body 400 is arranged so that the bottom side of the lid body 400 is located inside the exterior body 100X. In the energy storage device 10X, the bottom side of the lid body 400 does not necessarily have to be located inside the exterior body 100X. In the energy storage device 10X, the bottom side of the lid body 400 may be located outside the exterior body 100X. When the lid body 400 is a metal molded product or a resin molded product, it is preferable that the material constituting the lid body 400 has a certain thickness so that deformation of the exterior body 100X is suppressed even when the energy storage devices 10X are arranged one on top of the other. The minimum thickness of the material constituting the lid body 400 is, for example, 1.0 mm, more preferably 3.0 mm, and even more preferably 4.0 mm. The maximum thickness of the material constituting the lid body 400 is, for example, 20 mm, more preferably 15 mm, and even more preferably 10 mm. The maximum thickness of the material constituting the lid body 400 may be 20 mm or more. The preferred ranges of the thickness of the material constituting the lid body 400 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 the present disclosure, when the lid body 400 is expressed as a metal molded product or a resin molded product, the lid body 400 does not include a form constituted only by a film. The film is, for example, a film defined by the [packaging terminology] standard of the JIS (Japanese Industrial Standards). The film specified by the JIS [Packaging Terminology] standard is a plastic membrane with a thickness of less than 250 μm. The thickness of the material constituting the lid body 400 may vary depending on the part of the lid body 400. If the thickness of the material constituting the lid body 400 varies depending on the part of the lid body 400, the thickness of the material constituting the lid body 400 is the thickness of the thickest part.

In addition, when the electrode body 200 is stored, the electrode terminal 300 passes between the lid body 400 and the exterior member 101 and protrudes to the outside of the exterior body 100X. That is, the lid body 400 and the exterior member 101 are heat sealed with the electrode terminal 300 sandwiched between them. Note that in the power storage device 10X, the position from which the electrode terminal 300 protrudes to the outside does not necessarily have to be between the lid body 400 and the exterior member 101. For example, the electrode terminal 300 may protrude to the outside from a hole formed on any one of the six faces of the exterior body 100X. In this case, the small gap between the exterior body 100X and the electrode terminal 300 is filled with, for example, resin.

Furthermore, in the energy storage device 10X, the lid body 400 and the electrode terminal 300 are provided as separate bodies. However, the lid body 400 and the electrode terminal 300 do not necessarily have to be provided as separate bodies. For example, the lid body 400 and the electrode terminal 300 may be formed integrally.

12 is a diagram showing a first example in which the lid 400 and the electrode terminal 300 are integrally formed. As shown in FIG. 12, in the first example, the electrode terminal 300 is heat-sealed in advance to the side of the lid 400. For example, when the lid 400 is made of the exterior member 101, an adhesive film that adheres to both the metal and the resin described in the first embodiment may be placed between the lid 400 and the electrode terminal 300. When the adhesive film is made of two or more layers, it is preferable to place a resin film made of a polyolefin resin on the side that is joined to the lid 400. When the adhesive film is made of two or more layers, it is preferable to place a resin film made of an acid-modified polyolefin resin in which a polyolefin resin is graft-modified with an acid such as maleic anhydride on the side that is joined to the electrode terminal 300.

FIG. 13 is a diagram showing a second example in which the lid 400 and the electrode terminal 300 are integrally formed. As shown in FIG. 13, in the second example, the electrode terminal 300 passes through a hole formed in the bottom surface of the lid 400. The small gap in the hole in the bottom surface of the lid 400 is filled with, for example, resin.

In addition, in the energy storage device 10X, a gas valve may be attached to a hole formed in the second sealing portion 120X or any one of the six faces of the exterior body 100X. The gas valve is configured, for example, as a check valve or a breaker valve, and is configured to reduce the pressure inside the exterior body 100X when the pressure increases due to gas generated inside the energy storage device 10X.

<2-2. Manufacturing method of electricity storage device>
Fig. 14 is a flowchart showing an example of a manufacturing procedure for the power storage device 10X. The steps shown in Fig. 14 are performed, for example, by a manufacturing apparatus for the power storage device 10X. Note that the manufacturing procedure for the power storage device 10X can be changed as desired.

The manufacturing device wraps the exterior member 101 around the electrode body 200 (step S200). The manufacturing device forms the first sealing portion 110 by heat sealing the mutually facing surfaces (thermally adhesive resin layers) of the exterior member 101 (step S210). This results in the unfinished product shown in Figures 4 and 5.

The manufacturing equipment bends the first sealing portion 110 so that the first sealing portion 110 contacts the second surface 140 (step S220). The manufacturing equipment stores the electrode body 200 in the unfinished product produced in step S220 and attaches a lid body 400 to each of the openings at both ends (step S230). The manufacturing equipment forms the second sealing portion 120X by heat sealing the exterior member 101 and the lid body 400 (step S240). This completes the electricity storage device 10X.

<2-3. Features>
In the power storage device 10X according to the second embodiment, the first sealing portion 110 is also bent toward the second surface 140 having a smaller area. Therefore, according to the power storage device 10X, when a plurality of power storage devices 10X are stacked, it is possible to suppress unevenness in the distribution of pressure applied to the lower power storage device 10X.

<2-4. Other features>
In the power storage device 10X according to the second embodiment, the first sealing portion 110 does not necessarily have to be bent towards the second surface 140 having a smaller area. For example, the first sealing portion 110 may be bent towards the first surface 130 having a larger area. Furthermore, the root portion of the first sealing portion 110 does not necessarily have to be on the side 135 of the exterior body 100X. The root portion of the first sealing portion 110 may be located on a surface of the exterior body 100X other than the lid body 400, for example. Even in this case, the power storage device 10X according to the second embodiment includes, for example, the following features.

The energy storage device 10X comprises an electrode body (electrode body 200) and an exterior body (exterior body 100X) that seals the electrode body (electrode body 200). The exterior body (exterior body 100X) is wrapped around the electrode body (electrode body 200) and comprises an exterior member (exterior member 101) with openings formed at both ends, and a lid body (lid body 400) that seals the openings.

In the energy storage device 10X, the second sealed portion 120X is not formed by heat sealing the mutually facing surfaces of the exterior member 101 as in the first embodiment (see FIG. 7). In the energy storage device 10X, the opening of the exterior member 101 wrapped around the electrode body 200 is sealed by the lid body 400. That is, the second sealed portion 120X is formed in the portion where the lid body 400 and the exterior member 101 overlap (see FIGS. 9 and 10). With this configuration, the area of the second sealed portion 120X can be easily narrowed by adjusting the depth L3 (FIG. 11) of the lid body 400.

Furthermore, in the energy storage device 10X, at a position of the exterior member 101 that covers the corner C1 (FIGS. 9 and 10) of the electrode body 200, no excessive load is generated due to the corner C1 piercing the exterior member 101. This is because, as described above, in the energy storage device 10X, the second sealed portion 120X is not formed by heat sealing the mutually facing surfaces of the exterior member 101 as in the first embodiment.

Furthermore, the manufacturing procedure of the power storage device 10X is not limited to the procedure shown in the flowchart of FIG. 14. For example, the power storage device 10X may be manufactured according to the procedure shown in the flowchart of FIG. 15.

15 is a flow chart showing another manufacturing procedure of the power storage device 10X according to the second embodiment. The process shown in FIG. 15 is performed, for example, by a manufacturing apparatus for the power storage device 10X. The manufacturing apparatus attaches a member (for example, the member shown in FIGS. 12 and 13) in which the electrode terminal 300 and the lid body 400 are integrated to the electrode body 200 (step S250). For example, the electrode terminal 300 is welded to the electrode body 200. The manufacturing apparatus then wraps the exterior member 101 around the electrode body 200 (step S260). The manufacturing apparatus forms the first sealing portion 110 by heat-sealing the mutually facing surfaces (thermally adhesive resin layers) of the exterior member 101, and forms the second sealing portion 120X by heat-sealing the exterior member 101 and the lid body 400 (step S270). This completes the power storage device 10X. The power storage device 10X may be manufactured by such a procedure.

3. Third embodiment
In the battery manufacturing process, a temporarily sealed electricity storage device is generally subjected to a process of aging for a predetermined time in a predetermined temperature environment for the purpose of permeating an electrolyte into the electrode body (hereinafter referred to as an aging process). In the aging process, gas is generated from the electrode body 200, and it is necessary to discharge the gas to the outside of the battery. In the electricity storage device 10X according to the above-mentioned second embodiment, a mechanism for releasing the gas generated in the aging process in the final stage of the manufacture of the electricity storage device 10X is not provided. In the electricity storage device 10Y according to the third embodiment, a mechanism for releasing the gas generated from the electrode body 200 in the final stage of the manufacture of the electricity storage device 10Y is provided. In the following, differences from the second embodiment will be mainly described, and a description of the parts common to the second embodiment will be omitted.

3-1. Configuration of the power storage device
Fig. 16 is a side view showing a state in which the exterior member 101Y is wrapped around the electrode body 200 during the manufacture of the power storage device 10Y. Fig. 17 is a bottom view showing a state in which the exterior member 101Y is wrapped around the electrode body 200 and a lid body 400 is attached to the exterior member 101Y during the manufacture of the power storage device 10Y.

As shown in Figures 16 and 17, the piece 150 is formed when the exterior member 101Y is wrapped around the electrode body 200. The piece 150 is formed by joining the mutually facing surfaces of the exterior member 101Y when the exterior member 101Y is wrapped around the electrode body 200. More specifically, the piece 150 is formed by joining (heat sealing) the peripheries of the mutually facing surfaces when the exterior member 101Y is wrapped around the electrode body 200. That is, a first sealing portion 154 is formed on the periphery of the piece 150.

In addition, in the piece 150, a space 152 is formed where the opposing surfaces of the exterior member 101Y are not joined. In the vicinity of the side 135, joint regions 151 where the opposing surfaces of the exterior member 101Y are joined and unjoined regions 153 where the opposing surfaces of the exterior member 101Y are not joined are arranged alternately. That is, in the piece 150, a pattern of joint regions 151 is formed along the side 135.

The gas generated from the electrode body 200 is discharged to the outside of the exterior body 100Y by, for example, cutting off a portion of the piece 150 to release the sealed state of the exterior body 100Y. Note that the gas discharged to the outside of the exterior body 100Y here is not necessarily limited to the gas generated from the electrode body 200, but may be a gas other than the gas generated from the electrode body 200, such as air, water vapor, or hydrogen sulfide.

Then, the portion including the vicinity of side 135 is heat-sealed in a band shape, thereby sealing the exterior body 100Y again. This completes the energy storage device 10Y. In the completed energy storage device 10Y, near side 135, areas where the bonding strength between the opposing surfaces of the exterior member 101Y is strong and areas where the bonding strength between the surfaces is weak are alternately arranged along side 135. In other words, in the heat-sealed portion near side 135, thin and thick portions are alternately arranged along side 135. This is because, by heat-sealing the vicinity of side 135 again, the unbonded area 153 is single-sealed, but the bonded area 151 is double-sealed.

<3-2. Manufacturing method of electricity storage device>
Fig. 18 is a flowchart showing an example of a manufacturing procedure for the power storage device 10Y. The steps shown in Fig. 18 are performed by, for example, a manufacturing apparatus for the power storage device 10Y. Note that the manufacturing procedure for the power storage device 10Y can be changed as desired.

The manufacturing equipment wraps the exterior member 101Y around the electrode body 200 (step S300). The manufacturing equipment forms the first sealing portion 154 by heat-sealing the peripheral edges of the opposing surfaces (thermally adhesive resin layers) of the exterior member 101Y (step S310). The manufacturing equipment forms a pattern of the bonding area 151 by heat-sealing the opposing surfaces of the exterior member 101Y near the side 135 (step S320).

The manufacturing equipment attaches the lids 400 to the openings at both ends with the electrode body 200 housed in the unfinished product produced in step S320 (step S330). The manufacturing equipment forms the second sealed portion 120X by heat sealing the exterior member 101Y and the lid 400 (step S340). Then, an aging process is performed.

The manufacturing equipment removes gas generated during the aging process by, for example, cutting off piece 150 (step S350). The manufacturing equipment reseals exterior body 100Y by heat-sealing the portion of piece 150 including bonding region 151 into a strip shape and removing the edge portion (step S360). Thereafter, piece 150 is folded toward second surface 140 to complete energy storage device 10Y.

<3-3. Features>
In the power storage device 10Y according to the third embodiment, the piece 150 including the first sealing portion 154 is also folded toward the second surface 140 having a smaller area. Therefore, according to the power storage device 10Y, when a plurality of power storage devices 10Y are stacked, it is possible to suppress unevenness in the distribution of pressure applied to the lower power storage device 10Y. When used in an all-solid-state battery, it is necessary to apply high pressure uniformly from the outer surface of the battery to exhibit battery performance, and therefore the packaging form of the present invention is preferable.

[4. Fourth embodiment]
In the power storage device 10X according to the above-described second embodiment, the position from which the electrode terminal 300 protrudes to the outside is between the lid body 400 and the exterior member 101. However, the position from which the electrode terminal 300 protrudes to the outside is not limited thereto. Note that, in the following, the description will be centered on the parts that are different from the second embodiment, and the description of the parts that are common to the second embodiment will be omitted.

4-1. Configuration of the Power Storage Device
FIG. 19 is a plan view that shows a schematic diagram of an electric storage device 10XA according to the fourth embodiment. FIG. 20 is a side view that shows a schematic diagram of an electric storage device 10XA. The exterior body 100X of the electric storage device 10XA includes a pair of long sides 100XA and a pair of short sides 100XB in a plan view. The exterior body 100X is configured by fitting the lid body 400 into each of the openings along the long sides 100XA of the exterior member 101 that is wrapped around the electrode body 200. With the lid body 400 fitted in, the exterior member 101 and the lid body 400 are heat-sealed to form a second sealing portion 120X. A through hole (not shown) is formed in the lid body 400. The two electrode terminals 300 protrude from the through holes of the lid body 400 to the outside of the exterior body 100X. The two electrode terminals 300 are shaped to follow the long sides 100XA of the exterior body 100X. Small gaps between the through holes and the electrode terminals 300 are filled with, for example, resin. In the fourth embodiment, the first sealing portion 110 is formed on one side of the pair of short sides 100XB.

The position from which the electrode terminal 300 of the lid body 400 protrudes in the thickness direction (arrow UD direction) of the electricity storage device 10XA can be selected arbitrarily. In this embodiment 4, as shown in FIG. 20, the electrode terminal 300 protrudes from approximately the center of the lid body 400 to the outside of the exterior body 100X in the thickness direction of the electricity storage device 10XA. The length of the electrode terminal 300 in the depth direction (arrow FB direction) of the electricity storage device 10XA can be selected arbitrarily. In this embodiment 4, the length of the electrode terminal 300 in the depth direction (arrow FB direction) of the electricity storage device 10XA is substantially the same as the length of the electrode body 200.

<4-2. Features>
In the power storage device 10XA according to the fourth embodiment, the electrode terminals 300 are arranged along the long side 100XA that is longer in the depth direction, so that larger electrode terminals 300 can be used. This makes it possible to provide a high-output power storage device 10XA.

5. Modifications
The above-described embodiments are examples of possible forms of the exterior member for an electricity storage device, the electricity storage device, and the manufacturing method for an electricity storage device according to the present invention, and are not intended to limit the forms. The exterior member for an electricity storage device, the electricity storage device, and the manufacturing method for an electricity storage device according to the present invention may take forms different from those exemplified in the above-described embodiments. One example of such a form is a form in which a part of the configuration of each of the above-described embodiments is replaced, changed, or omitted, or a form in which a new configuration is added to each of the above-described embodiments. Below, some examples of modified examples of each of the above-described embodiments are shown. The above-described embodiments can also be combined within a range that does not cause technical contradiction.

<5-1>
In the above-mentioned embodiments 1-4, one exterior member is wound around the electrode body 200. However, it is not necessary that one exterior member is wound around the electrode body 200. For example, two or more exterior members may be wound around the electrode body 200.

21 is a side view showing the state in which the exterior members 101Z1 and 101Z2 are wrapped around the electrode body 200 during the manufacturing process of the electric storage device in the modified example. As shown in FIG. 21, the electrode body 200 is covered with the exterior members 101Z1 and 101Z2. The first sealing portion 110Z is formed by joining the opposing surfaces of the exterior members 101Z1 and 101Z2. In this example, each first sealing portion 110Z is folded toward the second surface 140Z side, not toward the first surface 130Z side. Even with this configuration, it is possible to suppress unevenness in the distribution of pressure applied to the lower electric storage device when multiple electric storage devices are stacked. When used 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 the packaging form of the present invention is preferable. In this example, each first sealing portion 110Z does not necessarily need to be folded. In this modified example, each sealing portion 110Z may be sealed while sandwiching a portion of the electrode terminal 300. Furthermore, in this modified example, each first sealing portion 110Z does not need to be formed on the side 135Z, and may protrude outward from approximately the center of the second surface 140Z in the thickness direction of the power storage device.

<5-2>
In addition, in the above-mentioned embodiments 1-4, the electrode body 200 is a so-called stack type configured by stacking a plurality of electrodes 210, but the form of the electrode body 200 is not limited to this. The electrode body 200 may be, for example, a so-called wound type configured by winding a positive electrode and a negative electrode via a separator. Furthermore, the electrode body 200 may be configured by stacking a plurality of so-called wound type electrode bodies.

<5-3>
In the above embodiment 1-4, the second surface 140 is a plane extending downward at a substantially right angle from the first surface 130. However, the form of the second surface 140 is not limited to this. For example, consider a case where the electrode body 200 is a wound electrode body with a plane and a curved surface formed on the outer periphery. Here, it is assumed that the area of the plane is larger than the area of the curved surface, the first surface 130 covers the plane of the electrode body, and the second surface 140 covers the curved surface of the electrode body. In this case, the second surface 140 may be configured as a curved surface. In this case, the boundary portion where the second surface 140 extends downward from the first surface 130 is the side 135.

<5-4>
In the third embodiment, the bonding regions 151 are formed in four locations. However, the number of locations where the bonding regions 151 are formed is not limited to this. For example, the bonding regions 151 may be formed in two locations near both ends along the side 135, in one location near the center of the side 135, or in five or more locations.

<5-5>
In addition, in the above-mentioned second embodiment, the electrode terminal 300 is disposed in the second sealing portion 120X, but the position where the electrode terminal 300 is disposed in the exterior body 100X is not limited thereto. For example, as shown in FIG. 22, in the above-mentioned second embodiment, the electrode terminal 300 can also be disposed in the first sealing portion 110. In other words, the first sealing portion 110 is sealed in a state where the electrode terminal 300 is sandwiched between them. In this modified example, at least one of the two electrode terminals 300 may be folded toward the second surface 140 side, may be folded toward the opposite side to the second surface 140, or may not be folded so as to protrude outward from the side 135. In this modified example, the electrode terminal 300 and the first sealing portion 110 can be easily sealed, so that the sealing property of the exterior body 100X is improved. In addition, the electrode body 200 can be easily accommodated in the exterior body 100X. In this modification, for example, the lid body 400 is fitted into each of the openings at both ends of the exterior member 101X as in the above-mentioned embodiment 2. With the lid body 400 fitted in, the exterior member 101X and the lid body 400 are heat-sealed to form the second sealing portion 120. In the embodiment 1 as well, the electrode terminal 300 may be disposed in the first sealing portion 110.

<5-6>
In addition, in the above-mentioned second embodiment, the configuration of the lid body 400 can be arbitrarily changed. FIG. 23 is a perspective view showing a lid body 500 which is a modified example of the lid body 400. The lid body 500 is, for example, plate-shaped and includes a first surface 500A facing the electrode body 200 (see FIG. 9) and a second surface 500B opposite to the first surface 500A. A hole 500C penetrating the first surface 500A and the second surface 500B is formed in the center of the lid body 500. The material constituting the lid body 500 is, for example, a resin. In this modified example, it is preferable that an adhesive film 530 which adheres to both the electrode terminal 300 and the lid body 500 is attached to a predetermined range including a portion of the electrode terminal 300 which is joined to the lid body 500. The specifications of the adhesive film 530 are the same as those of the adhesive film described in the first embodiment. In this modified example, the manufacturing method for the energy storage device 10X may include the steps of electrically connecting the electrode body 200 and the electrode terminal 300, manufacturing the lid body 500, and inserting the electrode terminal 300 connected to the electrode body 200 into the hole 500C of the lid body 500 (see FIG. 24 , hereinafter referred to as the “insertion step”).

When the lid body 500 is plate-shaped, it is preferable that the lid body 500 has a certain degree of thickness so that deformation of the exterior body 100X is suppressed even when the power storage device 10X is arranged on top of each other. From another perspective, when the lid body 500 is plate-shaped, it is preferable that the side of the lid body 500 has a certain degree of thickness so that the side of the lid body 500 and the exterior member 101X can be suitably heat-sealed when forming the second sealing portion 120X. The minimum value of the thickness of the lid body 500 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 500 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 500 may be 20 mm or more. The preferred ranges for the thickness of the material constituting the lid body 500 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 disclosure, when the lid body 500 is described as being plate-shaped, this does not include an embodiment in which the lid body 500 is composed only of a film as defined by the JIS (Japanese Industrial Standards) [Packaging Terminology] standard. The thickness of the lid body 500 may vary depending on the portion of the lid body 500. When the thickness of the lid body 500 varies depending on the portion, the thickness of the lid body 500 is the thickness of the thickest portion.

The lid 500 may be constructed from a member divided into a first portion 510 and a second portion 520, and may be manufactured by joining the first portion 510 and the second portion 520 so as to sandwich the electrode terminal 300 and the adhesive film 530. In these modified examples, if a gap occurs between the adhesive film 530 and the hole 500C, it is preferable that this gap be filled, for example, with a resin material such as hot melt or by resin welding.

When the lid body 500 is composed of a member divided into a first portion 510 and a second portion 520, the relationship between the width LA of the electrode terminal 300 and the width LB of the lid body 500 can be selected arbitrarily. From the viewpoint of more firmly joining the electrode terminal 300 and the lid body 500, it is preferable that the ratio RA of the width LA to the width LB is 50% or more. In the example shown in FIG. 25, the width LA and the width LB are substantially equal, in other words, the ratio RA is 100%. When the ratio RA is 50% or more, the area of the electrode terminal 300 that is joined to the lid body 500 is large, so that the electrode terminal 300 and the lid body 500 can be more firmly joined by heating the electrode terminal 300. In this modified example, it is preferable that the width LC of the adhesive film 530 is substantially equal to the width LA of the electrode terminal 300.

The lid body 500 may be manufactured by insert molding the lid body 500 onto the electrode terminal 300 to which the adhesive film 530 is attached. In this case, the manufacturing method of the electricity storage device 10X includes a step of electrically connecting the electrode body 200 and the electrode terminal 300, and a step of insert molding the lid body 500 onto the electrode terminal 300 in a state connected to the electrode body 200 (hereinafter referred to as the "insert molding step"). After the insert molding step, the exterior member 101 is wrapped around the electrode body 200 and the lid body 500. Note that in the insert molding step, it is preferable to place a heat insulating material for protecting the electrode body 200 between the electrode body 200 and the part where the lid body 500 is formed. It is preferable that the heat insulating material is removed after the insert molding step.

In these modified examples, as shown in FIG. 26, the exterior body 100X may be formed by joining the exterior member 101 and the second surface 500B of the lid body 500 with the lid body 500 fitted therein, forming the second sealing portion 120X. The joining means between the exterior member 101 and the second surface 500B of the lid body 500 is, for example, heat sealing. In this modified example, the exterior member 101 is joined to a wider area of the lid body 500, thereby improving the sealing property of the exterior body 100X. The lid body may be formed by folding the adhesive film 530, and the second sealing portion 120X may be formed by joining any part of the adhesive film 530 to the exterior member 101X. In these modified examples, it is preferable that a barrier layer is laminated on at least a part of the surface of the lid body 500. Alternatively, if the lid body 500 has multiple layers, a barrier layer may be formed on any layer. The material that constitutes the barrier layer is, for example, aluminum, steel plate, or stainless steel.

27 is a front view of a cover 600 of another modified example of the cover 400 in the above-mentioned embodiment 2. The cover 600 includes a metal part 610, which is a part where metal is exposed on the surface, and the metal part 610 and the electrode 210 of the electrode body 200 are welded. The cover 600 may be entirely composed of the metal part 610, or the metal part 610 may be partially formed. When the metal part 610 is partially formed, the cover 600 is composed of a material with a multilayer structure including a metal layer. When the cover 600 is composed of a material with a multilayer structure with a metal layer as an intermediate layer, the metal part 610 is a part where layers other than the metal layer are partially removed so that the metal layer is exposed. In the example shown in FIG. 27, the metal part 610 of the cover 600 functions as an electrode terminal, so that a space between the cover 600 and the electrode 210 is not required. Therefore, the power storage device 10X (see FIG. 9) can be configured to be small.

FIG. 28 is a front view of a lid body 700 which is another modified example of the lid body 400 in the above-mentioned embodiment 2. The lid body 700 includes a metal portion 710 made of a metal material, and a non-metal portion 720 connected to the metal portion 710 and made of a resin material. The metal portion 710 is welded to the electrode 210 of the electrode body 200. In the example shown in FIG. 28, the metal portion 710 of the lid body 700 functions as an electrode terminal, so that no space is required between the lid body 700 and the electrode 210. This allows the power storage device 10X (see FIG. 9) to be configured in a small size.

<5-7>
In the first embodiment, the second sealing portion 120 is formed by folding the exterior member 101 and heat-sealing the thermally adhesive resin layers of the exterior member 101. However, the method of forming the second sealing portion 120 is not limited to this. FIG. 29 is a plan view that shows a schematic diagram of an electric storage device 10 having a second sealing portion 120Y of a modified example. The exterior member 101 has a protruding portion 101XA that extends outward from the exterior body 100, and the thermally adhesive resin layers 101C of the protruding portion 101XA are heat-sealed to each other to form the second sealing portion 120Y. In the portion of the protruding portion 101XA where the electrode terminal 300 is disposed, the thermally adhesive resin layer 101C of the protruding portion 101XA and the electrode terminal 300 are heat-sealed. According to this modified example, the second sealing portion 120Y can be heat-sealed more firmly, so that the sealing property of the exterior body 100 is improved. In this modification, the protruding portion 101XA may be cut as necessary except for the portion heat-sealed to the electrode terminal 300. This modification can also be applied to the modification shown in FIG.

<5-8>
In the above-mentioned first embodiment, the shape of the exterior body 100 can be changed arbitrarily. As shown in FIG. 30A, the exterior body 100 may be composed of at least a first exterior member 101AX and a second exterior member 101BX. The specifications of the first exterior member 101AX and the second exterior member 101BX are similar to those of the exterior member 101. At least one of the first exterior member 101AX and the second exterior member 101BX is formed with a recess 101AY that accommodates the electrode body 200. In the example shown in FIG. 30A, the first exterior member 101AX is formed with a recess 101AY by, for example, cold forming. The second exterior member 101BX is formed with a recess 101BY by, for example, cold forming. One of the first exterior member 101AX and the second exterior member 101BX may be a sheet-like member in which no recess is formed.

As shown in FIG. 30B, the first exterior member 101AX and the second exterior member 101BX may be portions separated by folding back a single exterior member. In the example shown in FIG. 30B, the first exterior member 101AX may be formed with a recess 101AY for accommodating the electrode body 200. As shown in FIG. 30C, the peripheral edge of the first exterior member 101AX and the peripheral edge of the second exterior member 101BX folded back onto the first exterior member 101AX may be joined at the edges other than the folded edge to form a peripheral seal portion 100AR. As shown in FIG. 30D, at least a portion of the peripheral seal portion 100AR may be folded back to fit along the electrode body 200.

Examples of the exterior body 100 having a recess include the examples shown in Figures 30A, 30C, and 30D, as well as the so-called folding trays disclosed in Japanese Patent Application Publication Nos. 2019-102332 and 2019-102333.

In addition to the examples shown in Figures 30A, 30C, and 30D, the exterior body 100 may be a brick-type pouch (see Figure 29), a Gabeltop-type pouch, a standing-type pouch, a gusset-type pouch, a three-sided sealed pouch, a four-sided sealed pouch, or a pillow package.

<5-9>
In the above-mentioned first embodiment, the method of forming the first sealing portion 110 can be selected arbitrarily. As shown in FIG. 31, for example, the manufacturing apparatus may form the first sealing portion 110 by pressing the seal bar 800 to a position away from the base 135X of the portion 110Y of the exterior body 100 where the first sealing portion 110 is to be formed (see FIG. 8) in step S120. According to this manufacturing method, as shown in FIG. 32, the first sealing portion 110 is formed with a recess 110X which is a trace of the seal bar 800 being pressed. In the portion of the exterior body 100 where the recess 110X is formed, the surfaces (thermally adhesive resin layers) of the exterior member 101 facing each other are directly joined to each other. Between the recess 110X and the base 135X of the exterior body 100, a poly pool 900 in which a part of the resin constituting the exterior member 101 has melted out is formed between the surfaces of the exterior member 101 facing each other. In the portion between the recess 110X and the base 135X of the exterior body 100, the surfaces (thermally adhesive resin layers) of the exterior member 101 facing each other are joined via the poly pool 900. That is, in this modified example, the first sealing portion 110 includes a portion where the surfaces of the exterior member 101 facing each other are directly joined, and a portion where the surfaces of the exterior member 101 facing each other are joined via the poly pool 900. The poly pool 900 prevents water vapor and the like from entering the interior of the exterior body 100 from the outside, thereby improving the barrier properties of the exterior body 100. Note that when the seal bar 800 is pressed against the portion 110Y, it is necessary that the surfaces of the exterior member 101 facing each other in the portion where the poly pool 900 is formed, in other words, in the portion between the recess 110X and the base 135X, are in contact with each other.

The distance X between the root 135X and the edge 810 of the seal bar 800 in the LR direction, in other words, the distance between the root 135X and the recess 110X in the LR direction, can be selected arbitrarily. From the viewpoint of forming the poly pool 900 over a wider range, the distance X is preferably, for example, 1 mm or more, more preferably 1.5 mm or more, and even more preferably 1.7 mm or more. From the viewpoint of forming the first sealing portion 110 compactly, the distance X is preferably, for example, 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less. The preferred range of the distance X is, for example, about 1 mm or more and 10 mm or less, about 1 mm or more and 5 mm or less, about 1 mm or more and 3 mm or less, about 1.5 mm or more and 10 mm or less, about 1.5 mm or more and 5 mm or less, about 1.5 mm or more and 3 mm or less, about 1.7 mm or more and 10 mm or less, about 1.7 mm or more and 5 mm or less, and about 1.7 mm or more and 3 mm or less. The distance X is most preferably, for example, 2 mm. The distance X may be substantially 0. When the distance X is substantially 0, the seal bar 800 is pressed against the exterior body 100 so that the base 135X and the edge 810 of the seal bar 800 substantially coincide with each other. Note that substantially coinciding includes a case where the base 135X and the edge 810 of the seal bar 800 completely coincide with each other, and a case where the positions of the base 135X and the edge 810 of the seal bar 800 are slightly shifted due to an error during manufacturing or the like. Therefore, the distance X being substantially 0 also includes a case where the distance X is less than 1 mm, for example. These modified examples can be similarly applied to the second to fourth embodiments. Note that depending on the shape of the portion of the recess 110X corresponding to the edge 810 of the seal bar 800, the distance between the base 135X and the recess 110X may not be constant. In such a case, the distance X may be the distance between the center of the recess 110X and the center of the base 135X in the FB direction. In another example, the distance X may be calculated based on the average value of multiple values including the maximum and minimum values of the distance between the base 135X and the recess 110X. Similarly, depending on the shape of the base 135X, the distance between the base 135X and the recess 110X may not be constant. In such a case, the distance X may be the distance between the center of the base 135X and the center of the recess 110X in the FB direction. In another example, the distance X may be calculated based on the average value of multiple values including the maximum and minimum values of the distance between the recess 110X and the base 135X.

In the above-mentioned second embodiment, as shown in FIG. 33, the exterior body 100X may include a barrier film 91 that suppresses the permeation of the electrolyte. The barrier film 91 is preferably disposed at least between the inner surface of the exterior member 101X and the electrode body 200. The barrier film 91 is preferably bonded to the inner surface of the exterior member 101X. The barrier film 91 is preferably made of a material that allows the gas generated in the exterior body 100X to pass through. The material constituting the barrier film 91 is, for example, a resin film or a porous film. Since the exterior body 100X has the barrier film 91, the deterioration of the exterior member 101X due to the electrolyte can be suppressed.

In the above-mentioned first embodiment, as shown in FIG. 34, the exterior body 100 may include a buffer film 92 for increasing the strength of the exterior member 101. The buffer film 92 is preferably disposed on at least the corners 100Z of the interior surface of the exterior member 101. Since the exterior body 100 includes the buffer film 92, it is possible to prevent pinholes from occurring in the exterior body 100. The material constituting the buffer film 92 is, for example, a polyester-based material, a polyolefin-based material, or a fluorine-based material. In this modified example, as shown in FIG. 33, the second sealing portion 120 may be formed by joining the interior surface of the exterior member 101 and the electrode terminal 300. It is preferable that the space 93 between the second sealing portion 120 and the electrode body 200 is filled with an electrolyte.

In the above embodiment 1, it has been explained that an adhesive film that adheres to both metal and resin may be disposed between the electrode terminal 300 and the exterior member 101, but an adhesive film may also be disposed in a similar manner in other embodiments.

In the above-mentioned second embodiment, it was explained that an adhesive film that adheres to both metal and resin, similar to the first embodiment, may be disposed between the lid 400 and the electrode terminal 300, but an adhesive film may be disposed in a similar manner in other embodiments as well.

6. Examples
The inventors of the present application conducted a first test and a second test on the exterior members for an electricity storage device of the Examples and the Reference Example. Note that, in the following, for the sake of convenience of explanation, among the elements constituting the exterior members for an electricity storage device of the Examples and the Reference Example, the same elements as those in the embodiment will be described by using the same reference numerals as those in the embodiment.

<6-1. First test>
The first test is a test to confirm the limit forming depth when cold forming is performed for the exterior members 101 of Example 1 and Reference Example 1. In the first test, a slip agent was applied to both sides of the exterior members 101 of Example 1 and Reference Example 1, and cold forming was performed.

The exterior member 101 of Example 1 has a layer structure consisting of, from the outside, a PET film layer (base layer 101A)/adhesive/ONY film layer/adhesive/aluminum layer (barrier layer 101B)/acid-modified polypropylene layer/polypropylene layer (thermally adhesive resin layer 101C).

The PET film layer is 12 μm thick. The ONY film layer is 15 μm thick. The aluminum layer is 40 μm thick. The acid-modified polypropylene layer is 40 μm thick. The polypropylene layer is 40 μm thick. The material that makes up the aluminum layer is recycled 8021 material.

The specifications of the exterior member 101 of Reference Example 1 are the same as those of the exterior member 101 of Example 1, except that the material constituting the aluminum layer is virgin raw material rather than recycled material.

The limit forming depth of the exterior member 101 in Example 1 was 8.6 mm. The limit forming depth of the exterior member 101 in Reference Example 1 was 8.8 mm. Therefore, it was confirmed that even when recycled material is used as the material constituting the barrier layer 101B of the exterior member 101, a cold forming depth equivalent to that obtained when virgin raw material is used as the material constituting the barrier layer 101B of the exterior member 101 can be obtained.

<6-2. Second test>
The second test was a test to confirm the wrappability of the exterior members 101 of Example 2 and Reference Example 2 when they were wrapped around the electrode body 200 and the lid body 400.

The specifications of the exterior member 101 in Example 2 are the same as those of the exterior member 101 in Example 1. The specifications of the exterior member 101 in Reference Example 2 are the same as those of the exterior member 101 in Reference Example 1.

It was confirmed that the exterior member 101 of Example 2 and the exterior member 101 of Reference Example 2 could be wrapped around the electrode body 200 and the lid body 400 with little difference in wrinkles and slack. Therefore, even when recycled material is used as the material constituting the barrier layer 101B of the exterior member 101, it was confirmed that the same degree of windability around the electrode body 200 and the lid body 400 could be obtained as when virgin raw material was used as the material constituting the barrier layer 101B of the exterior member 101.

10, 10X, 10XA, 10Y, 10Z: Electric storage device 100, 100X, 100Y: Exterior body 101, 101Y, 101Z1, 101Z2: Exterior member 101A: Base material layer 101B: Barrier layer 101C: Thermally adhesive resin layer 101AX: First exterior member 101BX: Second exterior member 101AY: Recess 110, 110Z, 154: First sealing portion 200: Electrode body

Claims (6)

1. The laminate includes, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer.
   The barrier layer contains at least one of recycled materials selected from the group consisting of aluminum alloy, stainless steel, titanium steel, and steel plate.
   Exterior materials for electricity storage devices.
2. An exterior member for an electricity storage device;
   an electrode assembly packaged by the exterior member for an electricity storage device;
   The exterior member for an electricity storage device includes:
   The laminate includes, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer.
   The barrier layer contains at least one of recycled materials selected from the group consisting of aluminum alloy, stainless steel, titanium steel, and steel plate.
   Energy storage device.
3. The electricity storage device according to claim 2 , further comprising a first sealing portion sealed by joining mutually facing surfaces of the exterior member for the electricity storage device together in a state in which the electrode body is wrapped in the exterior member for the electricity storage device.
4. a lid that seals the electrode body together with the exterior member for the electricity storage device;
   The electricity storage device according to claim 2 , further comprising a second sealing portion in which the lid and the exterior member for an electricity storage device are joined together.
5. The exterior member for the electricity storage device includes a first exterior member and a second exterior member,
   The power storage device according to claim 2 , wherein at least one of the first exterior member and the second exterior member has a recess formed therein to accommodate the electrode assembly.
6. A method for producing the electricity storage device according to claim 2 or 3, comprising the steps of:
   The method includes a step of manufacturing the exterior member for an electricity storage device, which is composed of a laminate including, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer;
   The barrier layer contains at least one of recycled materials selected from the group consisting of aluminum alloy, stainless steel, titanium steel, and steel plate.
   A method for manufacturing an electricity storage device.