Exterior material for power storage device, manufacturing method thereof, and power storage device

Abstract

Provided is an exterior material for a power storage device, the exterior material being formed from a laminate comprising at least a base material layer, a barrier layer, and a thermally-fusible resin layer in this order from the outside, and the exterior material having a tensile strength at break of 180 MPa or greater as measured by the method below, and having a creep resistance characteristic of 10 minutes or more as measured by the method below. <Measurement of tensile strength at break> Each tensile strength at break in the machine direction (MD) of the exterior material for the power storage device is measured by a method compliant with the provisions of JIS K7127:1999 by using a tensile tester. The measurement conditions are such that a dumbbell 7 shape is used for a sample shape, the distance between target lines is 10 mm, the tensile speed is 0.5 mm / min, the test environment is set to a temperature of 120ºC, and the average value from three measurements is used. <Measurement of creep resistance characteristic> The exterior material for a power storage device is cut out so as to have a width of 60 mm in the transverse direction (TD) and a length of 150 mm in the MD direction and is then folded in half such that the thermally-fusible resin layer is positioned at the inside. The folded exterior material is then heat sealed using a 7 mm heat seal bar at a position 10 mm from the fold such that the thickness of the thermally-fusible resin layer is in a range of 60-95% the thickness prior to sealing. The resulting heat-sealed exterior material for a power storage device is then cut to a width of 15 mm to form a sample. Both of the mutually opposing ends of the sample are affixed to respective SUS plates (stainless steel plates) by using an adhesive, and a weight of 2 kg is applied to one side. The end on the opposite side is hung from the top of a thermostatic bath and stored in the thermostatic bath at 150ºC. The creep resistance is evaluated using the time until the sealed part opens. The SUS plates that are used have a thickness of 2 mm, a width of 30 mm, a length of 100 mm, and a weight of 42.5 g, and one side of the SUS plates is S-shaped.

Description

[Technical field]

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

[0002] Conventionally, various types of electricity storage devices have been developed, and in all electricity storage devices, exterior materials are essential components for sealing electricity storage device elements such as electrodes, electrolytes, etc. Conventionally, metallic exterior materials have been widely used as exterior materials for electricity storage devices.

[0003] Meanwhile, in recent years, various shapes as well as thinner and lighter weight are required for electricity storage devices along with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc. However, the metallic exterior materials for electricity storage devices that have been widely used in the past have the drawbacks of being difficult to keep up with the diversification of shapes and also having limitations in terms of weight reduction.

[0004] In recent years, a film-like laminate in which a base layer, a barrier layer, and a heat-sealable resin layer are laminated in this order has been proposed as an exterior material for an electricity storage device that can be easily processed into a variety of shapes and can be made thinner and lighter (see, for example, Patent Document 1).

[0005] In such an exterior material for an electricity storage device, a recess is generally formed by cold forming, and electricity storage device elements such as electrodes and an electrolyte are placed in the space formed by the recess, and the heat-sealable resin layer is then heat-sealed to obtain an electricity storage device in which the electricity storage device elements are housed inside the exterior material for an electricity storage device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2008-287971 A Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, the weight of electricity storage devices has been increasing due to the increase in their capacity, so the packaging materials for electricity storage devices are also required to have high load resistance. In addition, for example, all-solid-state batteries do not use liquid electrolytes, so it is expected that the temperature of the battery will reach 100°C or higher during charging, and they are required to exhibit high seal strength even in high-temperature environments such as 150°C.

[0008] Under these circumstances, a primary object of the present disclosure is to provide an exterior material for an electricity storage device that has high load-bearing properties and exhibits high sealing strength in a high-temperature environment of 150° C. Another object of the present disclosure is to provide a method for producing the exterior material for an electricity storage device, and an electricity storage device using the exterior material for an electricity storage device. [Means for solving the problem]

[0009] The inventors of the present disclosure have conducted extensive research to solve the above-mentioned problems, and as a result, have found that in an exterior packaging material for an electricity storage device composed of a laminate including, from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, by setting the tensile breaking strength and creep resistance to respective predetermined values ​​or more, high load-bearing properties and high seal strength in a high-temperature environment of 150°C can be exhibited.

[0010] The present disclosure has been completed based on these novel findings and through further investigations. That is, the present disclosure provides the following inventions.

[0011] The laminate includes at least a base layer, a barrier layer, and a heat-sealable resin layer in this order from the outside, An exterior material for an electricity storage device, having a tensile breaking strength, measured by the following method, of 180 MPa or more, and a creep resistance, measured by the following method, of 10 minutes or more.

[0012] <Measurement of tensile breaking strength> The tensile breaking strength in the MD direction of the exterior material for electricity storage devices is measured using a tensile tester in accordance with the method specified in JIS K7127: 1999. The measurement conditions are as follows: a dumbbell No. 7 sample shape, a gauge length of 10 mm, a tensile speed of 0.5 mm / min, and a test environment of 120°C. The average value is measured three times.

[0013] <Measurement of creep resistance> The electrical storage device exterior material is cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half so that the heat-sealing resin layer is on the inside, and heat-sealed at a position 10 mm from the fold with a 7 mm heat seal bar so that the thickness of the heat-sealing resin layer is in the range of 60% to 95% before sealing (i.e., the electrical storage device exterior material is cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half in the MD direction at the midpoint in the MD direction so that the heat-sealing resin layers face each other, and heat-sealed at a position 10 mm back from the fold in the MD direction with a 7 mm heat seal bar so that the thickness of the heat-sealing resin layer is in the range of 60% to 95% before sealing). The heat-sealed electrical storage device exterior material is cut out to a width of 15 mm to prepare a sample. Both opposing ends of the sample are attached to SUS plates (stainless steel plates) with adhesive, and a 2 kg weight is attached to one side. The other end is hung from above the thermostatic chamber and stored in the thermostatic chamber at 150°C. The SUS plate used is 2 mm thick, 30 mm wide, 100 mm long, and weighs 42.5 g, with one side in an S-shape.

[0014] <Load-bearing capacity evaluation of exterior materials for energy storage devices> The exterior material for the electric storage device is cut into two pieces so that the width in the TD direction is 300 mm and the length in the MD direction is 300 mm. The heat-sealing resin layers of the two exterior materials for the electric storage device are placed opposite each other, and the two opposing sides are heat-sealed (seal width 7 mm) under conditions of 240°C, surface pressure 1 MPa, and 3 seconds, and the remaining 300 mm side is also heat-sealed (seal width 7 mm) to seal the three sides. Next, a stainless steel plate 97 mm long, 70 mm wide, 38 mm thick, and weighing 2100 g is inserted between the heat-sealing resin layers (the length of the stainless steel plate is 97 mm, which is the insertion direction). The two corners of the opened side of the pouch thus obtained (inner dimensions are 286 mm x 293 mm) are fastened with clips, and the pouch is hung so that the MD direction is the up-down direction and left to stand for 3 minutes, after which the exterior material for the electric storage device is observed and evaluated as A or C based on the following evaluation criterion 1. A stainless steel plate weighing 2100 g is inserted between the layers of the heat-sealable resin of the pouch, and the weight at which the exterior material for an electricity storage device breaks is measured. Evaluation is made on the basis of A to C based on the following evaluation criteria 2. (Load-bearing capacity evaluation standard 1) A: There are no pinholes or cracks in the exterior material for the electricity storage device. C: The exterior material for the electricity storage device has a pinhole or a crack. (Load-bearing capacity evaluation standard 2) A: No break at 4200g B: Does not break at 2100g, breaks at 4200g C: Breaks at 2100g Effect of the Invention

[0015] According to the present disclosure, it is possible to provide an exterior material for an electricity storage device that has high load-bearing capacity and exhibits high sealing strength in a high-temperature environment of 150° C. In addition, according to the present disclosure, it is also possible to provide a manufacturing method for the exterior material for an electricity storage device, and an electricity storage device using the exterior material for an electricity storage device. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. [Diagram 2]1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. [Diagram 3] 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. [Figure 4] 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. [Diagram 5] FIG. 2 is a schematic diagram for illustrating a method for housing an electricity storage device element in a package formed from the exterior material for an electricity storage device of the present disclosure. [Figure 6] FIG. 2 is a schematic diagram for explaining a method for measuring seal strength. [Figure 7] FIG. 2 is a schematic diagram for explaining a method for measuring seal strength. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The exterior packaging material for an electricity storage device according to the present disclosure is composed of a laminate having, from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, and is characterized in that it has a tensile breaking strength of 180 MPa or more as measured by the following method, and a creep resistance of 10 minutes or more as measured by the following method. By having these characteristics, the exterior packaging material for an electricity storage device according to the present disclosure exhibits high load-bearing properties and high seal strength in a high-temperature environment of 150°C.

[0018] <Measurement of tensile breaking strength> The tensile breaking strength in the MD direction of the exterior material for electricity storage devices is measured using a tensile tester in accordance with the method specified in JIS K7127: 1999. The measurement conditions are as follows: a dumbbell No. 7 sample shape, a gauge length of 10 mm, a tensile speed of 0.5 mm / min, and a test environment of 120°C. The average value is measured three times. <Creep resistance measurement> The electrical storage device exterior material is cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half so that the heat-sealing resin layer is on the inside, and heat-sealed at a position 10 mm from the fold with a 7 mm heat seal bar so that the thickness of the heat-sealing resin layer is in the range of 60% to 95% before sealing (i.e., the electrical storage device exterior material is cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half in the MD direction at the midpoint in the MD direction so that the heat-sealing resin layers face each other, and heat-sealed at a position 10 mm back from the fold in the MD direction with a 7 mm heat seal bar so that the thickness of the heat-sealing resin layer is in the range of 60% to 95% before sealing). The heat-sealed electrical storage device exterior material is cut out to a width of 15 mm to prepare a sample. Both opposing ends of the sample are attached to SUS plates (stainless steel plates) with adhesive, and a 2 kg weight is attached to one side. The other end is hung from above the thermostatic chamber and stored in the chamber at 150°C. Creep resistance is evaluated based on the time it takes for the seal to open. The SUS plate used is 2 mm thick, 30 mm wide, 100 mm long, and weighs 42.5 g, with one side in an S-shape.

[0019] The exterior material for a power storage device of the present disclosure will be described in detail below. In the present disclosure, a numerical range indicated by "~" means "more than or equal to" or "less than or equal to". For example, the expression "2 to 15 mm" means 2 mm or more and 15 mm or less. In the numerical ranges described in the present disclosure in stages, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of another numerical range described in stages. In addition, the upper limit and the upper limit, the upper limit and the lower limit, or the lower limit and the lower limit described separately may be combined to form a numerical range. In addition, in the numerical ranges described in the present disclosure, the upper limit or the lower limit described in a certain numerical range may be replaced with a value shown in the examples.

[0020] In addition, in the exterior material for an electric storage device, the MD (Machine Direction) and TD (Transverse Direction) of the barrier layer 3 described later can usually be determined in the manufacturing process. For example, when the barrier layer 3 is made of a metal foil such as an aluminum alloy foil or a stainless steel foil, linear lines called rolling marks are formed on the surface of the metal foil in the rolling direction (RD) of the metal foil. Since the rolling marks extend along the rolling direction, the rolling direction of the metal foil can be grasped by observing the surface of the metal foil. In addition, in the manufacturing process of the laminate, the MD of the laminate usually coincides with the RD of the metal foil, so that the MD of the laminate can be identified by observing the surface of the metal foil of the laminate and identifying the rolling direction (RD) of the metal foil. In addition, since the TD of the laminate is perpendicular to the MD of the laminate, the TD of the laminate can also be identified.

[0021] In addition, when the MD of the electrical storage device exterior material cannot be identified due to rolling marks on the metal foil such as aluminum alloy foil or stainless steel foil, it can be identified by the following method. As a method for confirming the MD of the electrical storage device exterior material, there is a method of observing the cross section of the thermally adhesive resin layer of the electrical storage device exterior material with an electron microscope to confirm the sea-island structure. In this method, the direction parallel to the cross section in which the average diameter of the shape of the islands in the direction perpendicular to the thickness direction of the thermally adhesive resin layer was maximum can be determined as the MD. Specifically, the cross section in the length direction of the thermally adhesive resin layer and each cross section (total of 10 cross sections) in the direction perpendicular to the cross section in the length direction, which are changed in angle by 10 degrees each, are observed with an electron microscope to confirm the sea-island structure. Next, the shape of each individual island is observed in each cross section. For the shape of each island, the straight line distance connecting the leftmost end in the direction perpendicular to the thickness direction of the thermally adhesive resin layer and the rightmost end in the perpendicular direction is defined as the diameter y. For each cross section, the average of the top 20 diameters y of the island shapes is calculated in descending order of size. The direction parallel to the cross section with the largest average diameter y of the island shapes is determined as the MD.

[0022] 1.Layer structure and physical properties of exterior materials for energy storage devices The exterior material 10 for an electricity storage device according to the present disclosure is composed of a laminate including at least a base layer 1, a barrier layer 3, and a heat-sealable resin layer 4 in this order, as shown in, for example, FIG. 1 to FIG. 4. In the exterior material 10 for an electricity storage device, the base layer 1 is the outermost layer, and the heat-sealable resin layer 4 is the innermost layer. When assembling an electricity storage device using the exterior material 10 for an electricity storage device and an electricity storage device element, the heat-sealable resin layers 4 of the exterior material 10 for an electricity storage device are placed opposite each other, and the electricity storage device element is accommodated in a space formed by heat-sealing the periphery. In the laminate constituting the exterior material 10 for an electricity storage device according to the present disclosure, the barrier layer 3 is used as a reference, and the heat-sealable resin layer 4 side is on the inner side relative to the barrier layer 3, and the base layer 1 side is on the outer side relative to the barrier layer 3.

[0023] As shown in Figures 2 to 4, for example, the exterior material 10 for an electricity storage device may have an adhesive layer 2 between the base material layer 1 and the barrier layer 3, if necessary, for the purpose of increasing the adhesion between these layers. Also, as shown in Figures 3 and 4, for example, the exterior material 10 for an electricity storage device may have an adhesive layer 5 between the barrier layer 3 and the heat-sealable resin layer 4, if necessary, for the purpose of increasing the adhesion between these layers. Also, as shown in Figure 4, a surface coating layer 6 or the like may be provided on the outer side of the base material layer 1 (the side opposite to the heat-sealable resin layer 4 side), if necessary.

[0024] The thickness of the laminate constituting the electricity storage device exterior material 10 is not particularly limited, but from the viewpoint of cost reduction, energy density improvement, etc., examples of the thickness include about 300 μm or less, about 280 μm or less, about 210 μm or less, preferably about 190 μm or less, about 180 μm or less, about 155 μm or less, and about 120 μm or less. Moreover, from the viewpoint of maintaining the function of the electricity storage device exterior material 10, which is to protect the electricity storage device elements, the thickness of the laminate constituting the electricity storage device exterior material 10 is preferably about 35 μm or more, about 45 μm or more, and about 60 μm or more. Furthermore, preferred ranges for the laminate constituting the exterior material 10 for an electricity storage device are, for example, about 35 to 300 μm, about 35 to 280 μm, about 35 to 210 μm, about 35 to 190 μm, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 45 to 210 μm, about 45 to 190 μm, about 45 to 180 μm, about 45 to 300 μm, and about 45 to 280 μm. , about 45 to 155 μm, about 45 to 120 μm, about 60 to 300 μm, about 60 to 280 μm, about 60 to 210 μm, about 60 to 190 μm, about 60 to 180 μm, about 60 to 155 μm, and about 60 to 120 μm. In particular, when making an electricity storage device lighter and thinner, about 60 to 155 μm is preferable, and when improving formability, about 155 to 190 μm is preferable.

[0025] The electrical storage device exterior material 10 can be suitably applied to an all-solid-state battery. In this case, the thickness of the laminate constituting the electrical storage device exterior material 10 is not particularly limited, but from the viewpoints of cost reduction, energy density improvement, etc., it is preferably about 10000 μm or less, about 8000 μm or less, or about 5000 μm or less, and from the viewpoint of maintaining the function of the all-solid-state battery exterior material to protect the battery element, it is preferably about 10 μm or more, about 15 μm or more, or about 20 μm or more, and the preferred ranges are, for example, about 10 to 10000 μm, about 10 to 8000 μm, about 10 to 5000 μm, about 15 to 10000 μm, about 15 to 8000 μm, about 15 to 5000 μm, about 20 to 10000 μm, about 20 to 8000 μm, and about 20 to 5000 μm, and particularly about 20 to 5000 μm is preferred.

[0026] In the exterior material 10 for an electricity storage device, the ratio of the total thickness of the base material layer 1, the adhesive layer 2 provided as needed, the barrier layer 3, the adhesive layer 5 provided as needed, the heat-sealable resin layer 4, and the surface coating layer 6 provided as needed to the thickness (total thickness) of the laminate constituting the exterior material 10 for an electricity storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the exterior material 10 for an electricity storage device of the present disclosure includes the base material layer 1, the adhesive layer 2, the barrier layer 3, the adhesive layer 5, and the heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the exterior material 10 for an electricity storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Furthermore, even when the exterior packaging material 10 for an electricity storage device of the present disclosure is a laminate including a substrate layer 1, an adhesive layer 2, a barrier layer 3, and a heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the exterior packaging material 10 for an electricity storage device can be, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0027] The exterior material 10 for an electricity storage device according to the present disclosure has a tensile breaking strength of 180 MPa or more as measured by the following method. From the viewpoint of more suitably exerting the effects of the present disclosure, the tensile breaking strength is preferably about 185 MPa or more, more preferably about 190 MPa or more, and even more preferably about 200 MPa or more, and is also preferably about 1000 MPa or less, more preferably about 900 MPa or less, and even more preferably about 800 MPa or less, and preferred ranges include about 180 to 1000 MPa, about 180 to 900 MPa, about 180 to 800 MPa, about 185 to 1000 MPa, about 185 to 900 MPa, about 185 to 800 MPa, about 190 to 1000 MPa, about 190 to 900 MPa, about 190 to 800 MPa, about 200 to 1000 MPa, about 200 to 900 MPa, and about 200 to 800 MPa.

[0028] <Measurement of tensile breaking strength> The tensile breaking strength in the MD direction of the exterior material for electricity storage devices is measured using a tensile tester in accordance with the method specified in JIS K7127: 1999. The measurement conditions are as follows: a dumbbell No. 7 sample shape, a gauge length of 10 mm, a tensile speed of 0.5 mm / min, and a test environment of 120°C. The average value is measured three times.

[0029] Furthermore, the exterior material 10 for an electricity storage device according to the present disclosure has a creep resistance property of 10 minutes or more as measured by the following method. From the viewpoint of more suitably exerting the effects of the present disclosure, the creep resistance property is preferably about 15 minutes or more, more preferably about 30 minutes or more, and even more preferably about 60 minutes or more, and is also preferably about 22000 minutes or less, more preferably about 20000 minutes or less, and even more preferably about 19000 minutes or less, and preferred ranges include about 10 to 22000 minutes, about 10 to 20000 minutes, about 10 to 19000 minutes, about 15 to 22000 minutes, about 15 to 20000 minutes, about 15 to 19000 minutes, about 30 to 22000 minutes, about 30 to 20000 minutes, about 30 to 19000 minutes, about 60 to 22000 minutes, about 60 to 20000 minutes, and about 60 to 19000 minutes.

[0030] <Creep resistance measurement> The electrical storage device exterior material is cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half so that the heat-sealing resin layer is on the inside, and heat-sealed at a position 10 mm from the fold with a 7 mm heat seal bar so that the thickness of the heat-sealing resin layer is in the range of 60% to 95% before sealing (i.e., the electrical storage device exterior material is cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half in the MD direction at the midpoint in the MD direction so that the heat-sealing resin layers face each other, and heat-sealed at a position 10 mm back from the fold in the MD direction with a 7 mm heat seal bar so that the thickness of the heat-sealing resin layer is in the range of 60% to 95% before sealing). The heat-sealed electrical storage device exterior material is cut out to a width of 15 mm to prepare a sample. Both opposing ends of the sample are attached to SUS plates (stainless steel plates) with adhesive, and a 2 kg weight is attached to one side. The other end is hung from above a thermostatic chamber and stored in the chamber at 150°C. The SUS plate used is 2 mm thick, 30 mm wide, 100 mm long, weighs 42.5 g, and has an S-shaped edge on one side. Creep resistance is evaluated based on the time it takes for the seal to open. Measurements are performed three times and the average value is used for evaluation. (Creep resistance evaluation criteria) A: The seal does not open for more than 10 minutes. C: The seal opens in less than 10 minutes.

[0031] Furthermore, the exterior packaging material 10 for an electricity storage device according to the present disclosure has a seal strength in a 150°C environment measured by the following measurement method of preferably 40 N / 15 mm or more, more preferably 45 N / 15 mm or more. The upper limit of the seal strength is, for example, 200 N / 15 mm or less, preferably 150 N / 15 mm or less. Preferred ranges of the seal strength include about 40 to 200 N / 15 mm, about 40 to 150 N / 15 mm, about 45 to 200 N / 15 mm, and about 45 to 150 N / 15 mm.

[0032] <Seal strength measurement in 150℃ environment> In accordance with the provisions of JIS K7127:1999, the seal strength of the exterior material at a measurement temperature of 150°C is measured as follows. A test piece cut into a strip with a width of 15 mm in the TD direction is prepared from the exterior material in the following procedure. Specifically, as shown in Figure 6, first, each exterior material is cut to 60 mm (TD direction) x 200 mm (MD direction) (Figure 6a). Next, the exterior material is folded in half in the MD direction at the fold P (middle in the MD direction) so that the heat-sealable resin layers face each other (Figure 6b). The heat-sealable resin layers are heat-sealed to each other 10 mm inside the fold P in the MD direction under the conditions of a seal width of 7 mm, a temperature of 240°C, a surface pressure of 1 MPa, and a time of 3 seconds (Figure 6c). In Figure 6c, the shaded area S is the heat-sealed part. Next, the specimen is cut in the MD direction (cut at the position of the two-dot chain line in Figure 6d) so that the width in the TD direction is 15 mm, and a test piece 13 is obtained (Figure 6e). Next, the test piece 13 is left in an environment at 150°C for 2 minutes, and in the 150°C environment, the heat-sealable resin layer of the heat-sealed portion is peeled off at a speed of 300 mm / min using a tensile tester (Figure 7). The maximum strength at the time of peeling is taken as the seal strength (N / 15 mm). The distance between the chucks is 50 mm. Measurements are performed three times and the average value is used.

[0033] 2. Each layer that forms the exterior material for electricity storage devices [Base material layer 1] In the present disclosure, the substrate layer 1 is a layer provided for the purpose of exhibiting the function as a substrate of the exterior material for an electricity storage device, etc. The substrate layer 1 is located on the outer layer side of the exterior material for an electricity storage device.

[0034] The material forming the base layer 1 is not particularly limited as long as it has the function of a base, that is, at least insulating properties. The base layer 1 can be formed using, for example, a resin, and the resin may contain additives described later.

[0035] When the substrate layer 1 is formed of a resin, the substrate layer 1 can be formed of, for example, a resin film. When the substrate layer 1 is formed of a resin film, a preformed resin film may be used as the substrate layer 1 when the substrate layer 1 is laminated with the barrier layer 3 or the like to manufacture the exterior material for an electricity storage device 10 of the present disclosure. In addition, the resin forming the substrate layer 1 may be formed into a film on the surface of the barrier layer 3 or the like by extrusion molding, coating, or the like to form the substrate layer 1 formed of a resin film. The resin film may be an unstretched film or a stretched film. Examples of the stretched film include a uniaxially stretched film and a biaxially stretched film, and a biaxially stretched film is preferable. Examples of the stretching method for forming a biaxially stretched film include a sequential biaxial stretching method, an inflation method, and a simultaneous biaxial stretching method. Examples of the method for applying the resin include a roll coating method, a gravure coating method, and an extrusion coating method.

[0036] Examples of the resin forming the base layer 1 include polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenol resin, as well as modified versions of these resins. The resin forming the base layer 1 may be a copolymer of these resins or a modified version of the copolymer. Furthermore, it may be a mixture of these resins.

[0037] The base layer 1 preferably contains these resins as the main component, and more preferably contains polyester or polyamide as the main component. Here, the main component means that the content of the resin components contained in the base layer 1 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, the base layer 1 contains polyester or polyamide as the main component means that the content of polyester or polyamide among the resin components contained in the base layer 1 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0038] Of these, preferred examples of the resin forming the base layer 1 include polyester and polyamide.

[0039] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyesters. Examples of copolymerized polyesters include copolymerized polyesters in which ethylene terephthalate is the main repeating unit. Specific examples of polyesters include copolymerized polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), and polyethylene (terephthalate / decane dicarboxylate). These polyesters may be used alone or in combination of two or more.

[0040] Specific examples of polyamides include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid, and T represents terephthalic acid) that contain structural units derived from terephthalic acid and / or isophthalic acid, and polyamides containing aromatic compounds such as polyamide MXD6 (polymetaxylylene adipamide); alicyclic polyamides such as polyamide PACM6 (polybis(4-aminocyclohexyl)methane adipamide); polyamides copolymerized with a lactam component or an isocyanate component such as 4,4'-diphenylmethane diisocyanate; polyesteramide copolymers and polyetheresteramide copolymers that are copolymers of copolymerized polyamides with polyesters or polyalkylene ether glycols; and polyamides such as copolymers of these copolymers. These polyamides may be used alone or in combination of two or more.

[0041] The base layer 1 preferably includes at least one of a polyester film, a polyamide film, and a polyolefin film, preferably includes at least one of a stretched polyester film, a stretched polyamide film, and a stretched polyolefin film, more preferably includes at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, a stretched nylon film, and a stretched polypropylene film, and even more preferably includes at least one of a biaxially oriented polyethylene terephthalate film, a biaxially oriented polybutylene terephthalate film, a biaxially oriented nylon film, and a biaxially oriented polypropylene film.

[0042] The base layer 1 may be a single layer, or may be composed of two or more layers. When the base layer 1 is composed of two or more layers, the base layer 1 may be a laminate in which resin films are laminated with an adhesive or the like, or may be a laminate of resin films in which resins are co-extruded to form two or more layers. In addition, a laminate of resin films in which resins are co-extruded to form two or more layers may be used as the base layer 1 without being stretched, or may be uniaxially or biaxially stretched to form the base layer 1.

[0043] In the base layer 1, specific examples of the laminate of two or more resin films include a laminate of a polyester film and a nylon film, a laminate of two or more nylon films, and a laminate of two or more polyester films, and preferably a laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more stretched nylon films, and a laminate of two or more stretched polyester films. For example, when the base layer 1 is a laminate of two resin films, a laminate of a polyester resin film and a polyester resin film, a laminate of a polyamide resin film and a polyamide resin film, or a laminate of a polyester resin film and a polyamide resin film is preferred, and a laminate of a polyethylene terephthalate film and a polyethylene terephthalate film, a laminate of a nylon film and a nylon film, or a laminate of a polyethylene terephthalate film and a nylon film is more preferred. In addition, when the base layer 1 is a laminate of two or more resin films, it is preferable that the polyester resin film is located in the outermost layer of the base layer 1, because the polyester resin is less likely to discolor when, for example, an electrolyte is attached to the surface.

[0044] When the base layer 1 is a laminate of two or more resin films, the two or more resin films may be laminated via an adhesive. Examples of preferred adhesives include the same adhesives as those exemplified in the adhesive layer 2 described below. The method for laminating two or more resin films is not particularly limited, and a known method can be adopted, such as a dry lamination method, a sandwich lamination method, an extrusion lamination method, a thermal lamination method, etc., and preferably a dry lamination method. When laminating by the dry lamination method, it is preferable to use a polyurethane adhesive as the adhesive. In this case, the thickness of the adhesive is, for example, about 2 to 5 μm. Also, an anchor coat layer may be formed on the resin film and laminated. Examples of the anchor coat layer include the same adhesives as those exemplified in the adhesive layer 2 described below. In this case, the thickness of the anchor coat layer is, for example, about 0.01 to 1.0 μm.

[0045] Furthermore, additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, antistatic agents, colorants, etc. may be present on at least one of the surface and the interior of the base material layer 1. Only one type of additive may be used, or two or more types may be mixed and used.

[0046] In the present disclosure, from the viewpoint of improving the moldability of the exterior material for a power storage device, it is preferable that a lubricant is present on at least one of the surface and the inside of the base material layer 1. The lubricant is not particularly limited, but is preferably an amide-based lubricant. Specific examples of amide-based lubricants include, for example, saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of saturated fatty acid amides include lauric acid amides, palmitic acid amides, stearic acid amides, behenic acid amides, and hydroxystearic acid amides. Specific examples of unsaturated fatty acid amides include oleic acid amides and erucic acid amides. Specific examples of substituted amides include N-oleyl palmitic acid amides, N-stearyl stearic acid amides, N-stearyl oleic acid amides, N-oleyl stearic acid amides, and N-stearyl erucic acid amides. Specific examples of methylol amides include methylol stearic acid amides. Specific examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, N,N'-distearyl sebacic acid amide, etc. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipic acid amide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamide ethyl stearate, etc. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N,N'-distearylisophthalic acid amide.The lubricant may be used alone or in combination of two or more kinds, and it is preferable to use a combination of two or more kinds.

[0047] When a lubricant is present on the surface of the base layer 1, the amount of the lubricant is not particularly limited, but may be, for example, about 3 mg / m 2 or more, preferably about 4 mg / m 2 More than about 5mg / m 2 The amount of lubricant present on the surface of the base layer 1 is, for example, about 15 mg / m 2 Less than or equal to about 14 mg / m 2 Below, about 10mg / m 2 The preferred range of the amount of lubricant present on the surface of the base layer 1 is 3 to 15 mg / m 2 degree, 3~14mg / m 2 degree, 3~10mg / m 2 degree, 4~15mg / m 2 degree, 4~14mg / m 2 degree, 4~10mg / m 2 degree, 5~15mg / m 2 degree, 5~14mg / m 2 degree, 5~10mg / m 2 The degree of

[0048] The lubricant present on the surface of the base layer 1 may be a lubricant exuded from the resin constituting the base layer 1, or a lubricant applied to the surface of the base layer 1.

[0049] The thickness of the substrate layer 1 is not particularly limited as long as it functions as a substrate, and may be, for example, about 3 μm or more, preferably about 10 μm or more. The thickness of the substrate layer 1 may be, for example, about 50 μm or less, preferably about 35 μm or less, 13 μm or less, 11 μm or less, 8 μm or less, 7 μm or less, or 6 μm or less. The preferred range of the thickness of the substrate layer 1 may be about 3 to 50 μm, about 3 to 35 μm, about 3 to 13 μm, about 3 to 11 μm, about 3 to 8 μm, about 3 to 7 μm, about 3 to 6 μm, about 10 to 50 μm, about 10 to 35 μm, or about 10 to 13 μm. In particular, when making the electricity storage device lighter and thinner, about 3 to 35 μm, about 3 to 11 μm, about 3 to 8 μm, about 3 to 7 μm, or about 3 to 6 μm is preferred, and when improving the formability, about 35 to 50 μm is preferred. When the base layer 1 is a laminate of two or more resin films, the thickness of each resin film constituting each layer is not particularly limited, but may be, for example, about 2 μm or more, preferably about 10 μm or more, and about 18 μm or more. The thickness of each resin film constituting each layer may be, for example, about 33 μm or less, preferably about 28 μm or less, about 23 μm or less, about 18 μm or less, 11 μm or less, and 8 μm or less. The preferred ranges of the thickness of each resin film constituting each layer include about 2 to 33 μm, about 2 to 28 μm, about 2 to 23 μm, about 2 to 18 μm, about 2 to 11 μm, about 2 to 8 μm, about 10 to 33 μm, about 10 to 28 μm, about 10 to 23 μm, about 10 to 18 μm, about 18 to 33 μm, about 18 to 28 μm, and about 18 to 23 μm.

[0050] The base layer 1 contains a colorant, so that the exterior material for an electricity storage device can be colored. As the colorant, known substances such as pigments and dyes can be used. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

[0051] The type of pigment is not particularly limited as long as it does not impair the function as a substrate of the substrate layer 1. Examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments, while examples of inorganic pigments include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments, and other examples include fine powder of mica, fish scale foil, and the like.

[0052] Among colorants, carbon black is preferred in order to give the exterior material for an electricity storage device a black appearance, and mica is preferred from the viewpoint of dissipating heat generated from the electricity storage device.

[0053] The average particle size of the pigment is not particularly limited and may be, for example, about 0.03 to 5 μm, and preferably about 0.05 to 2 μm. The average particle size of the pigment is the median size measured by a laser diffraction / scattering type particle size distribution measuring device.

[0054] The content of the colorant in the base layer 1 is not particularly limited as long as the exterior material for an electricity storage device is colored, and is, for example, about 5 to 60 mass %, and preferably about 10 to 40 mass %.

[0055] [Adhesive layer 2] In the exterior material for an electricity storage device of the present disclosure, the adhesive layer 2 is a layer that is provided between the base layer 1 and the barrier layer 3 as necessary for the purpose of increasing the adhesion between them.

[0056] The adhesive layer 2 is formed of an adhesive capable of bonding the base material layer 1 and the barrier layer 3. The adhesive used to form the adhesive layer 2 is not limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot pressure type, etc. Also, it may be a two-component curing adhesive (two-component adhesive), a one-component curing adhesive (one-component adhesive), or a resin that does not involve a curing reaction. Also, the adhesive layer 2 may be a single layer or multiple layers.

[0057] Specific examples of adhesive components contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyesters; polyethers; polyurethanes; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolymerized polyamides; polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins; polyvinyl acetate; cellulose; (meth)acrylic resins; polyimides; polycarbonates; amino resins such as urea resins and melamine resins; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; and silicone resins. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, polyurethane adhesives are preferred. In addition, the adhesive strength of these adhesive component resins can be increased by using an appropriate curing agent in combination. The curing agent is selected from polyisocyanates, multifunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, and the like, depending on the functional groups of the adhesive components.

[0058] Examples of polyurethane adhesives include polyurethane adhesives containing a first agent containing a polyol compound and a second agent containing an isocyanate compound. A two-liquid curing type polyurethane adhesive is preferably used, in which a polyol such as polyester polyol, polyether polyol, and acrylic polyol is used as the first agent, and an aromatic or aliphatic polyisocyanate is used as the second agent. Examples of polyurethane adhesives include polyurethane adhesives containing a polyurethane compound in which a polyol compound and an isocyanate compound have been reacted in advance, and an isocyanate compound. Examples of polyurethane adhesives include polyurethane adhesives containing a polyurethane compound in which a polyol compound and an isocyanate compound have been reacted in advance, and a polyol compound. Examples of polyurethane adhesives include polyurethane adhesives in which a polyurethane compound in which a polyol compound and an isocyanate compound have been reacted in advance is cured by reacting it with moisture in the air or the like. As the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group on the side chain in addition to the hydroxyl group at the end of the repeating unit. Examples of the second agent include aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds. Examples of isocyanate compounds include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and naphthalene diisocyanate (NDI). In addition, examples include polyfunctional isocyanate modified products of one or more of these diisocyanates. In addition, a polymer (e.g., a trimer) can also be used as the polyisocyanate compound. Examples of such polymers include adducts, biuret bodies, and nurate bodies. Since the adhesive layer 2 is formed from a polyurethane adhesive, excellent electrolyte resistance is imparted to the exterior material for an electricity storage device, and peeling of the base material layer 1 is suppressed even if the electrolyte adheres to the side surface.

[0059] In addition, the adhesive layer 2 is allowed to contain other components as long as they do not impair adhesion, and may contain a colorant, a thermoplastic elastomer, a tackifier, a filler, etc. By containing a colorant in the adhesive layer 2, the exterior material for a power storage device can be colored. As the colorant, known colorants such as pigments and dyes can be used. In addition, only one type of colorant may be used, or two or more types may be mixed and used.

[0060] The type of pigment is not particularly limited as long as it does not impair the adhesiveness of the adhesive layer 2. Examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments, while examples of inorganic pigments include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments, and other examples include fine powder of mica, fish scale foil, and the like.

[0061] Among colorants, carbon black is preferred in order to give the exterior material for an electricity storage device a black appearance, for example.

[0062] The average particle size of the pigment is not particularly limited and may be, for example, about 0.03 to 5 μm, and preferably about 0.05 to 2 μm. The average particle size of the pigment is the median size measured by a laser diffraction / scattering type particle size distribution measuring device.

[0063] The content of the colorant in the adhesive layer 2 is not particularly limited as long as the exterior material for an electricity storage device is colored, and is, for example, about 5 to 60 mass %, preferably 10 to 40 mass %.

[0064] The thickness of the adhesive layer 2 is not particularly limited as long as it can bond the base layer 1 and the barrier layer 3, but is, for example, about 1 μm or more, about 2 μm or more. The thickness of the adhesive layer 2 is, for example, about 10 μm or less, about 5 μm or less. Preferable ranges for the thickness of the adhesive layer 2 include about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

[0065] [Colored layer] The colored layer is a layer that is provided between the base material layer 1 and the barrier layer 3 as necessary (not shown). When the adhesive layer 2 is provided, a colored layer may be provided between the base material layer 1 and the adhesive layer 2, or between the adhesive layer 2 and the barrier layer 3. Also, a colored layer may be provided on the outside of the base material layer 1. By providing a colored layer, the exterior material for an electricity storage device can be colored.

[0066] The colored layer can be formed, for example, by applying an ink containing a colorant to the surface of the base layer 1 or the surface of the barrier layer 3. As the colorant, known substances such as pigments and dyes can be used. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

[0067] Specific examples of the colorant contained in the colored layer include the same as those exemplified in the section [Adhesive layer 2].

[0068] [Barrier layer 3] In the packaging material for an electricity storage device, the barrier layer 3 is a layer that at least prevents the penetration of moisture.

[0069] Examples of the barrier layer 3 include metal foils, vapor-deposited films, and resin layers having barrier properties. Examples of the vapor-deposited films include metal vapor-deposited films, inorganic oxide vapor-deposited films, and carbon-containing inorganic oxide vapor-deposited films. Examples of the resin layer include fluorine-containing resins such as polyvinylidene chloride, polymers mainly composed of chlorotrifluoroethylene (CTFE), polymers mainly composed of tetrafluoroethylene (TFE), polymers having fluoroalkyl groups, and polymers mainly composed of fluoroalkyl units, and ethylene-vinyl alcohol copolymers. Examples of the barrier layer 3 include resin films having at least one of these vapor-deposited films and resin layers. The barrier layer 3 may be provided in a plurality of layers. The barrier layer 3 preferably includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 3 include aluminum alloys, stainless steel, titanium steel, and steel plates. When used as a metal foil, it is preferable to include at least one of aluminum alloy foil and stainless steel foil.

[0070] In the barrier layer 3, the layer made of the above-mentioned metal material may contain recycled metal material. Examples of recycled metal material include recycled aluminum alloy, stainless steel, titanium steel, or steel plate. These recycled materials can be obtained by known methods. The recycled aluminum alloy material can be obtained by the manufacturing method described in International Publication No. 2022 / 092231. The barrier layer 3 may be made of only recycled materials, or may be made of a mixed material of recycled materials and virgin materials. Note that recycled metal materials refer to metal materials that have been made reusable by collecting, isolating, and refining various products used in the city and waste from the manufacturing process. In addition, virgin metal materials refer to new metal materials refined from natural metal resources (raw materials) and are not recycled materials.

[0071] From the viewpoint of improving the formability of the exterior material for a power storage device, 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, 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%, more preferably 0.5 to 2.0 mass%. By making the iron content 0.1 mass% or more, an exterior material for a power storage device having better formability can be obtained. By making the iron content 9.0 mass% or less, an exterior material for a power 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.

[0072] Examples of the stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. From the viewpoint of providing an exterior material for an electricity storage device having excellent formability, the stainless steel foil is preferably made of austenitic stainless steel.

[0073] Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, and SUS316L, and among these, SUS304 is particularly preferred.

[0074] In the case of a metal foil, the thickness of the barrier layer 3 should be such that it at least functions as a barrier layer to prevent the intrusion of moisture, and may be, for example, about 9 to 200 μm. The thickness of the barrier layer 3 is preferably about 150 μm or less, more preferably about 100 μm or less, even more preferably about 90 μm or less, and particularly preferably about 85 μm or less. The thickness of the barrier layer 3 is preferably about 40 μm or more, more preferably about 50 μm or more, and more preferably about 55 μm or more. Preferable ranges of the thickness of the barrier layer 3 include about 40 to 150 μm, about 40 to 100 μm, about 40 to 90 μm, about 40 to 85 μm, about 50 to 150 μm, about 50 to 100 μm, about 50 to 90 μm, about 50 to 85 μm, about 55 to 150 μm, about 55 to 100 μm, about 55 to 90 μm, and about 55 to 85 μm. When the barrier layer 3 is made of an aluminum alloy foil, the above-mentioned ranges are particularly preferable. From the viewpoint of imparting high formability and high rigidity to the exterior material 10 for an electricity storage device, the thickness of the barrier layer 3 is preferably about 35 μm or more, more preferably about 45 μm or more, even more preferably about 50 μm or more, and still 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 still more preferably about 70 μm or less. Preferred 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. The high formability of the exterior material 10 for an electricity storage device makes deep drawing easy, which can contribute to increasing the 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 increased rigidity of the exterior material 10 for an electricity storage device can contribute to high sealing performance of the electricity storage device.In particular, when the barrier layer 3 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 of 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.

[0075] In addition, when the barrier layer 3 is a metal foil, it is preferable to provide a corrosion-resistant film at least on the surface opposite to the base layer in order to prevent dissolution and corrosion. The barrier layer 3 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 surface of the barrier layer 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. Specifically, the corrosion-resistant film means a film that improves the acid resistance of the barrier layer (acid-resistant film), a film that improves the alkali resistance of the barrier layer (alkali-resistant film), etc. As a treatment for forming a corrosion-resistant film, one type may be performed, or two or more types may be combined. In addition, not only one layer but also multiple layers may be formed. Furthermore, among these treatments, the hydrothermal conversion treatment and the 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. These treatments may be included in the definition of “chemical conversion treatment.” In addition, when the barrier layer 3 has a corrosion-resistant coating, the barrier layer 3 includes the corrosion-resistant coating.

[0076] The corrosion-resistant coating prevents delamination between a barrier layer (e.g., an aluminum alloy foil) and a base layer during molding of an exterior material for an electricity storage device, prevents dissolution and corrosion of the barrier layer surface due to hydrogen fluoride produced by a reaction between an electrolyte and moisture, and in particular prevents dissolution and corrosion of aluminum oxide present on the barrier layer surface when the barrier layer is an aluminum alloy foil, and also improves the adhesion (wettability) of the barrier layer surface, thereby preventing delamination between the base layer and the barrier layer during heat sealing and between the base layer and the barrier layer during molding.

[0077] Various corrosion-resistant films formed by chemical conversion treatments are known, and mainly include corrosion-resistant films containing at least one of phosphates, chromates, fluorides, triazine thiol compounds, and rare earth oxides. Examples of chemical conversion treatments using phosphates and chromates include chromate chromate treatment, phosphoric acid chromate treatment, phosphoric acid-chromate treatment, and chromate treatment. Examples of chromium compounds used in these treatments include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromate acetyl acetate, chromium chloride, and potassium chromium sulfate. Examples of phosphorus compounds used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, and polyphosphoric acid. Examples of chromate treatments include etching chromate treatment, electrolytic chromate treatment, and coating-type chromate treatment, and coating-type chromate treatment is preferred. In this coating type chromate treatment, at least the inner layer side of the barrier layer (e.g., aluminum alloy foil) is first degreased by a known treatment method such as an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, or an acid activation method, and then the degreased surface is coated with a treatment liquid mainly composed of a metal phosphate such as Cr (chromium) phosphate, Ti (titanium) phosphate, Zr (zirconium) phosphate, or Zn (zinc) phosphate, or a mixture of these metal salts, or a treatment liquid mainly composed of a nonmetallic phosphate and a mixture of these nonmetallic salts, or a treatment liquid consisting of a mixture of these with a synthetic resin, or the like, by a known coating method such as a roll coating method, a gravure printing method, or a dipping method, and then dried. As the treatment liquid, various solvents such as water, alcohol-based solvents, hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, and ether-based solvents can be used, and water is preferred. Examples of the resin component used here include polymers such as phenolic resins and acrylic resins, and chromate treatment using an aminated phenol polymer having repeating units represented by the following general formulas (1) to (4). In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more types.The acrylic resin is preferably polyacrylic acid, acrylic acid methacrylic acid ester copolymer, acrylic acid maleic acid copolymer, acrylic acid styrene copolymer, or a derivative thereof such as sodium salt, ammonium salt, or amine salt. In particular, a derivative of polyacrylic acid such as an ammonium salt, sodium salt, or amine salt of polyacrylic acid is preferable. In the present disclosure, polyacrylic acid means a polymer of acrylic acid. The acrylic resin is also preferably a copolymer of acrylic acid and dicarboxylic acid or dicarboxylic acid anhydride, and is also preferably an ammonium salt, sodium salt, or amine salt of a copolymer of acrylic acid and dicarboxylic acid or dicarboxylic acid anhydride. Only one type of acrylic resin may be used, or two or more types may be mixed and used.

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] In the general formulas (1) to (4), X represents a hydrogen atom, a hydroxy group, an alkyl group, a hydroxyalkyl group, an allyl group, or a benzyl group. 1 and R 2 In the general formulae (1) to (4), X and R each independently represent a hydroxy group, an alkyl group, or a hydroxyalkyl group. 1 and R 2Examples of the alkyl group represented by the formula (I) include linear or branched alkyl groups having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. 1 and R 2 Examples of the hydroxyalkyl group represented by the formula (1) to (4) include linear or branched alkyl groups having 1 to 4 carbon atoms substituted with one hydroxy group, such as a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, and a 4-hydroxybutyl group. 1 and R 2 The alkyl group and the hydroxyalkyl group represented by the following formulae may be the same or different. In the general formulae (1) to (4), X is preferably a hydrogen atom, a hydroxy group, or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having the repeating units represented by the general formulae (1) to (4) is preferably about 500 to 1,000,000, for example, and more preferably about 1,000 to 20,000. The aminated phenol polymer can be prepared, for example, by polycondensing a phenol compound or a naphthol compound with formaldehyde to produce a polymer consisting of the repeating units represented by the above general formula (1) or (3), and then polycondensing the polymer with formaldehyde and an amine (R 1 R 2 NH) to the functional group (-CH 2 NR 1 R 2 The aminated phenol polymers can be used alone or in combination of two or more.

[0083] Another example of the corrosion-resistant film is a thin film formed by a coating-type corrosion prevention treatment in which a coating agent containing at least one selected from the group consisting of rare earth element oxide sol, anionic polymer, and cationic polymer is applied. The coating agent may further contain phosphoric acid or a phosphate, and a crosslinking agent for crosslinking the polymer. The rare earth element oxide sol has rare earth element oxide fine particles (for example, particles with an average particle size of 100 nm or less) dispersed in a liquid dispersion medium. Examples of rare earth element oxides include cerium oxide, yttrium oxide, neodymium oxide, and lanthanum oxide, and cerium oxide is preferred from the viewpoint of further improving adhesion. The rare earth element oxide contained in the corrosion-resistant film can be used alone or in combination of two or more. Examples of the liquid dispersion medium for the rare earth element oxide sol include various solvents such as water, alcohol-based solvents, hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, and ether-based solvents, and water is preferred. As the cationic polymer, for example, polyethyleneimine, an ionic polymer complex consisting of a polymer having polyethyleneimine and a carboxylic acid, a primary amine grafted acrylic resin in which a primary amine is graft-polymerized to an acrylic main skeleton, polyallylamine or its derivative, aminated phenol, etc. are preferable. In addition, as the anionic polymer, poly(meth)acrylic acid or its salt, or a copolymer mainly composed of (meth)acrylic acid or its salt, is preferable. In addition, it is preferable that the crosslinking agent is at least one selected from the group consisting of a compound having any one of a functional group of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, and a silane coupling agent. In addition, it is preferable that the phosphoric acid or the phosphoric acid salt is a condensed phosphoric acid or a condensed phosphate salt.

[0084] One example of a corrosion-resistant coating is one formed by applying a solution of fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide, or barium sulfate dispersed in phosphoric acid to the surface of a barrier layer and baking the coating at 150°C or higher.

[0085] If necessary, the corrosion-resistant coating may have a laminated structure in which at least one of a cationic polymer and an anionic polymer is further laminated. Examples of the cationic polymer and anionic polymer include those mentioned above.

[0086] The composition of the corrosion-resistant film can be analyzed by, for example, time-of-flight secondary ion mass spectrometry.

[0087] The amount of the corrosion-resistant film formed on the surface of the barrier layer 3 in the chemical conversion treatment is not particularly limited. For example, in the case of coating-type chromate treatment, the amount of the corrosion-resistant film formed on the surface of the barrier layer 3 is preferably 1 mm. 2 It is desirable that the chromate compound is contained in an amount, calculated as chromium, of about 0.5 to 50 mg, preferably about 1.0 to 40 mg, the phosphorus compound is contained in an amount, calculated as phosphorus, of about 0.5 to 50 mg, preferably about 1.0 to 40 mg, and the aminated phenol polymer is contained in an amount, calculated as phosphorus, of about 1.0 to 200 mg, preferably about 5.0 to 150 mg, per unit weight of the ink.

[0088] The thickness of the corrosion-resistant film is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably about 1 nm to 100 nm, and even more preferably about 1 nm to 50 nm, from the viewpoint of the cohesive strength of the film and the adhesive strength with the barrier layer and the heat-sealable resin layer. The thickness of the corrosion-resistant film can be measured by observation with a transmission electron microscope, or a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron energy loss spectroscopy. Analysis of the composition of the corrosion-resistant film using time-of-flight secondary ion mass spectrometry can reveal that, for example, secondary ions consisting of Ce, P, and O (e.g., Ce 2 PO 4 + , CePO 4 - At least one of the above) and secondary ions consisting of, for example, Cr, P and O (e.g., CrPO 2 + , CrPO 4 - Peaks derived from at least one of the above are detected.

[0089] The chemical conversion treatment is carried out by applying a solution containing a compound used for forming a corrosion-resistant film to the surface of the barrier layer by a bar coating method, a roll coating method, a gravure coating method, a dipping method, or the like, and then heating the barrier layer so that the temperature of the barrier layer becomes about 70 to 200°C. In addition, before applying the chemical conversion treatment to the barrier layer, the barrier layer may be subjected to a degreasing treatment by an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, or the like. By carrying out the degreasing treatment in this manner, it becomes possible to carry out the chemical conversion treatment of the surface of the barrier layer more efficiently. In addition, by using an acid degreasing agent in which a fluorine-containing compound is dissolved in an inorganic acid for the degreasing treatment, it is possible to not only degrease the metal foil but also form a fluoride of the metal that is in a passive state, and in such a case, only the degreasing treatment may be carried out.

[0090] [Thermal adhesive resin layer 4] In the exterior packaging material for an electricity storage device of the present disclosure, the heat-sealable resin layer 4 includes the innermost layer and is a layer (sealant layer) that exhibits the function of sealing the electricity storage device elements by heat-sealing the heat-sealable resin layers to each other when the electricity storage device is assembled.

[0091] In the present disclosure, the heat-fusible resin contained in the heat-fusible resin layer 4 is not particularly limited as long as it is a resin having heat fusibility and does not impair the effects of the present disclosure, and examples thereof include thermoplastic resins, etc. From the viewpoint of more suitably exerting the effects of the present disclosure, the heat-fusible resin layer 4 preferably contains polybutylene terephthalate, and more preferably contains at least one of homopolybutylene terephthalate and copolymer polybutylene terephthalate.

[0092] The heat-sealable resin layer 4 is preferably formed, for example, from a homopolybutylene terephthalate film, and the content of homopolybutylene terephthalate is preferably 80 mass % or more, more preferably 85 mass % or more, and even more preferably 90 mass % or more.

[0093] When the heat-sealable resin layer 4 is a resin layer made of a homopolybutylene terephthalate film, the resin contained in the heat-sealable resin layer 4 is substantially only homopolybutylene terephthalate (for example, 99% by mass or more, or even 100% by mass or more). That is, the heat-sealable resin layer 4 in this case is formed of a homopolybutylene terephthalate film that does not substantially contain any resin other than homopolybutylene terephthalate. For example, the heat-sealable resin layer 4 in this case is a layer made of a homopolybutylene terephthalate film that does not contain any resin other than elastomer and copolymerized polybutylene terephthalate.

[0094] The homopolybutylene terephthalate contained in the heat-sealable resin layer 4 may or may not be acid-modified. When the homopolybutylene terephthalate is an acid-modified homopolybutylene terephthalate, the acid modification of the homopolybutylene terephthalate can be carried out with an acid component such as maleic anhydride or acrylic acid.

[0095] The heat-fusible resin layer 4 formed from homopolybutylene terephthalate has a melting peak temperature of, for example, 220 to 230° C. In the present disclosure, the melting peak temperature of the resin constituting the layer is an endothermic peak measured by a differential scanning calorimeter (DSC), and is specifically measured by the following method.

[0096] <Measurement of melting peak temperature> The melting peak temperature of the resin forming the layer is measured in accordance with the provisions of JIS K7121:2012 (Method of measuring transition temperature of plastics (JIS K7121:1987 Supplement 1)). The measurement is performed using a differential scanning calorimeter. The measurement sample is held at -50°C for 15 minutes, then heated from -50°C to 300°C at a heating rate of 10°C / min, the first melting peak temperature P (°C) is measured, and then held at 300°C for 2 minutes. Next, the temperature is lowered from 300°C to -50°C at a heating rate of 10°C / min and held for 15 minutes. Furthermore, the temperature is raised from -50°C to 300°C at a heating rate of 10°C / min, and the second melting peak temperature Q (°C) is measured. The flow rate of nitrogen gas is 50 ml / min. By the above procedure, the melting peak temperature P (°C) measured the first time and the melting peak temperature Q (°C) measured the second time are determined, and the melting peak temperature measured the first time is designated as the melting peak temperature.

[0097] It is also preferable that the heat-sealable resin layer 4 is a layer containing copolymerized polybutylene terephthalate. When the heat-sealable resin layer 4 is formed of copolymerized polybutylene terephthalate, the content of copolymerized polybutylene terephthalate contained in the heat-sealable resin layer 4 is preferably 3 mass% or more, more preferably 5 mass% or more, and further preferably 10 mass% or more.

[0098] When the heat-sealable resin layer 4 is a resin layer made of a copolymerized polybutylene terephthalate film, the resin contained in the heat-sealable resin layer 4 is substantially only copolymerized polybutylene terephthalate (for example, 99% by mass or more, or even 100% by mass or more). That is, the heat-sealable resin layer 4 in this case is formed of a copolymerized polybutylene terephthalate film that does not substantially contain any resin other than copolymerized polybutylene terephthalate. For example, the heat-sealable resin layer 4 in this case is a layer made of a copolymerized polybutylene terephthalate film that does not contain any resin other than elastomer and copolymerized polybutylene terephthalate.

[0099] From the viewpoint of more suitably exerting the effects of the present invention, the melting peak temperature of the heat-fusible resin layer 4 containing copolymerized polybutylene terephthalate is preferably 170° C. or higher, more preferably 190° C. or higher, and even more preferably 200° C. or higher, and is preferably 350° C. or lower, more preferably 300° C. or lower, more preferably 270° C. or lower, even more preferably 230° C. or lower, and even more preferably 217° C. or lower. Preferred ranges include about 170 to 350° C., about 170 to 300° C., about 170 to 270° C., about 170 to 230° C., about 170 to 217° C., about 190 to 350° C., about 190 to 300° C., about 190 to 270° C., about 190 to 230° C., about 190 to 217° C., about 200 to 350° C., about 200 to 300° C., about 200 to 270° C., about 200 to 230° C., and about 200 to 217° C. The method for measuring the melting peak temperature is as described above.

[0100] In the present disclosure, the copolymerized polybutylene terephthalate contained in the thermally adhesive resin layer 4 preferably contains, in addition to the polybutylene terephthalate structure, at least one selected from the group consisting of a polyether structure and a polyester structure B. Here, the polyester structure B is a structure different from the polybutylene terephthalate structure.

[0101] The polyether structure can be introduced into the resin by polycondensation reaction of a polyvalent carboxylic acid (i.e., terephthalic acid) having a polybutylene terephthalate structure with a compound (monomer) having a polyether structure. The polyether structure desirably constitutes a soft segment of the resin in the heat-fusible resin layer 4. Examples of compounds (monomers) that form such soft segments by polycondensation reaction with a polyvalent carboxylic acid (i.e., terephthalic acid) having a polybutylene terephthalate structure include diols that can exhibit elasticity, such as polytetramethylene ether glycol and neopentyl glycol. The polyether structure is preferably a polyether structure derived from at least one selected from the group consisting of polytetramethylene ether glycol and neopentyl glycol. Polytetramethylene ether glycol, neopentyl glycol, and the like form structural units in the polyether structure of the resin. By introducing a polyether structure into the resin as a soft segment, the rubber elasticity of the resin is increased and the resin becomes less likely to break, so that high sealing strength is suitably exhibited in a low-temperature environment.

[0102] The polyester structure B can be introduced into the resin by using a compound (monomer) that undergoes a polycondensation reaction with butanediol used in the polybutylene terephthalate structure to form a polyester structure. The polyester structure B desirably constitutes a soft segment of the resin in the heat-sealable resin layer 4, and examples of the compound (monomer) that undergoes a polycondensation reaction with butanediol in the polybutylene terephthalate structure to form such a soft segment include aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, dodecanedioic acid, and cyclohexanedicarboxylic acid (preferably an aliphatic dicarboxylic acid having 4 to 20 carbon atoms). The aromatic dicarboxylic acid, aliphatic dicarboxylic acid, and the like form a structural unit in the polyester structure B of the resin. It is particularly preferable that the polyester structure B is a polyester structure obtained by polycondensation of a polyol and at least one dicarboxylic acid selected from the group consisting of isophthalic acid, sebacic acid, and dodecanedioic acid. By introducing the polyester structure B as a soft segment into the resin, the rubber elasticity of the resin is increased and the resin becomes less likely to break, so that high sealing strength is suitably exhibited in a low-temperature environment.

[0103] From the viewpoint of more suitably exerting the effects of the present invention, it is particularly preferred that the resin forming the thermally adhesive resin layer 4 further contains a polyether structure in addition to the polybutylene terephthalate structure, and that the polyether structure has a polycondensation structure of at least one of polytetramethylene ether glycol and neopentyl glycol and terephthalic acid having a polybutylene terephthalate structure. It is also particularly preferred that the resin forming the thermally adhesive resin layer 4 further contains a polyester structure B in addition to the polybutylene terephthalate structure, and that the polyester structure B has a polycondensation structure of at least one selected from the group consisting of isophthalic acid, dodecanedioic acid, and sebacic acid, and 1,4-butanediol having a polybutylene terephthalate structure.

[0104] In order to more suitably exert the effects of the present invention, the copolymerized polybutylene terephthalate forming the thermally adhesive resin layer 4 preferably has a polybutylene terephthalate structure as a main component. The main component means that the ratio of the total components constituting the resin is 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, relative to 100% by mass of all components constituting the resin. In addition, the resin forming the thermally adhesive resin layer 4 has a ratio of at least one of a polyether structure and a dicarboxylic acid structure of preferably about 2 to 30% by mass, more preferably about 3 to 25% by mass, and even more preferably about 3 to 20% by mass, relative to 100% by mass of all components (total monomer units) constituting the resin.

[0105] The heat-sealable resin layer 4 may be a layer containing at least one of homopolybutylene terephthalate and copolymer polybutylene terephthalate, or may be a layer not containing homopolybutylene terephthalate and copolymer polybutylene terephthalate. The resin other than polybutylene terephthalate is not particularly limited as long as it does not impair the effects of the present disclosure, and examples of the resin include thermoplastic resins having better heat resistance than polypropylene, such as polyethylene terephthalate and ETFE.

[0106] The heat-sealable resin layer 4 may contain a resin containing a polyolefin skeleton as a main component, may contain polyolefin as a main component, and preferably contains polypropylene as a main component. Here, the main component means that the content of the resin components contained in the heat-sealable resin layer 4 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, the heat-sealable resin layer 4 containing polypropylene as a main component means that the content of polypropylene of the resin components contained in the heat-sealable resin layer 4 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0107] Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. Among these, polypropylene is preferred. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. These polyolefin resins may be used alone or in combination of two or more.

[0108] The polyolefin may be a cyclic polyolefin. The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefins constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of the cyclic monomers constituting the cyclic polyolefin include cyclic alkenes such as norbornene; and cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these, cyclic alkenes are preferred, and norbornene is more preferred.

[0109] The polyolefin may be an acid-modified polyolefin. The acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of a polyolefin with an acid component. The polyolefin to be acid-modified may be the above-mentioned polyolefin, a copolymer obtained by copolymerizing the above-mentioned polyolefin with a polar molecule such as acrylic acid or methacrylic acid, or a polymer such as a crosslinked polyolefin. The acid component used for the acid modification may be, for example, a carboxylic acid or an anhydride such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, or itaconic anhydride.

[0110] The acid-modified polyolefin may be an acid-modified cyclic polyolefin. The acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin by replacing it with an acid component, or by block-polymerizing or graft-polymerizing an acid component to the cyclic polyolefin. The cyclic polyolefin to be acid-modified is the same as described above. The acid component used for the acid modification is the same as the acid component used for the modification of the polyolefin.

[0111] Preferred acid-modified polyolefins include polyolefins modified with a carboxylic acid or anhydride thereof, polypropylenes modified with a carboxylic acid or anhydride thereof, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

[0112] The thermally adhesive resin layer 4 may be formed of one type of resin alone, or may be formed of a blend polymer of two or more types of resins. Furthermore, the thermally adhesive resin layer 4 may be formed of only one layer, or may be formed of two or more layers of the same or different resins.

[0113] The thermally adhesive resin layer 4 may contain a lubricant, etc., if necessary. When the thermally adhesive resin layer 4 contains a lubricant, the moldability of the exterior material for a power storage device can be improved. The lubricant is not particularly limited, and a known lubricant can be used.

[0114] The lubricant is not particularly limited, but preferably includes an amide-based lubricant. Specific examples of the lubricant include those exemplified for the base layer 1. The lubricant may be used alone or in combination of two or more types, and is preferably used in combination of two or more types.

[0115] In the present disclosure, from the viewpoint of improving the moldability of the exterior material for a power storage device, it is preferable that a lubricant is present on at least one of the surface and the inside of the heat-sealable resin layer 4. The lubricant is not particularly limited, but preferably includes an amide-based lubricant. Specific examples of amide-based lubricants include, for example, saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of saturated fatty acid amides include lauric acid amides, palmitic acid amides, stearic acid amides, behenic acid amides, and hydroxystearic acid amides. Specific examples of unsaturated fatty acid amides include oleic acid amides and erucic acid amides. Specific examples of substituted amides include N-oleyl palmitic acid amides, N-stearyl stearic acid amides, N-stearyl oleic acid amides, N-oleyl stearic acid amides, and N-stearyl erucic acid amides. Specific examples of methylol amides include methylol stearic acid amides. Specific examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, N,N'-distearyl sebacic acid amide, etc. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipic acid amide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamide ethyl stearate, etc. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N,N'-distearylisophthalic acid amide.The lubricant may be used alone or in combination of two or more kinds, and it is preferable to use a combination of two or more kinds.

[0116] When a lubricant is present on the surface of the heat-sealable resin layer 4, the amount of the lubricant is not particularly limited. However, from the viewpoint of improving the formability of the exterior material for an electrical storage device, the amount of the lubricant is preferably about 1 mg / m 2 More preferably, about 3 mg / m 2 More preferably, about 5 mg / m 2 More preferably, about 10 mg / m 2 More preferably, about 15 mg / m 2 or more, and preferably about 50 mg / m 2 or less, more preferably about 40 mg / m 2 The preferred range is 1 to 50 mg / m 2 degree, 1~40mg / m 2 degree, 3~50mg / m 2 degree, 3~40mg / m 2 degree, 5~50mg / m 2 degree, 5~40mg / m 2 degree, 10~50mg / m 2 degree, 10~40mg / m 2 degree, 15~50mg / m 2 degree, 15~40mg / m 2 The degree of

[0117] When a lubricant is present inside the heat-sealable resin layer 4, the amount of the lubricant is not particularly limited, but from the viewpoint of improving the moldability of the exterior material for an electrical storage device, it is preferably about 100 ppm or more, more preferably about 300 ppm or more, and even more preferably about 500 ppm or more, and is preferably about 3000 ppm or less, more preferably about 2000 ppm or less, and preferred ranges include about 100 to 3000 ppm, about 100 to 2000 ppm, about 300 to 3000 ppm, about 300 to 2000 ppm, about 500 to 3000 ppm, and about 500 to 2000 ppm. When two or more types of lubricants are present inside the heat-sealable resin layer 4, the above amount of lubricant is the total amount of lubricant. Furthermore, when two or more types of lubricants are present inside the heat-sealable resin layer 4, the amount of the first type of lubricant is not particularly limited, but from the viewpoint of improving the formability of the exterior material for an electricity storage device, it is preferably about 100 ppm or more, more preferably about 300 ppm or more, even more preferably about 500 ppm or more, and is preferably about 3000 ppm or less, more preferably about 2000 ppm or less, and preferred ranges include about 100 to 3000 ppm, about 100 to 2000 ppm, about 300 to 3000 ppm, about 300 to 2000 ppm, about 500 to 3000 ppm, and about 500 to 2000 ppm. The amount of the second type of lubricant is not particularly limited, but from the viewpoint of improving the formability of the exterior material for an electricity storage device, it is preferably about 50 ppm or more, more preferably about 100 ppm or more, and even more preferably about 200 ppm or more, and is preferably about 1500 ppm or less, more preferably about 1000 ppm or less, and preferred ranges include about 50 to 1500 ppm, about 50 to 1000 ppm, about 100 to 1500 ppm, about 100 to 1000 ppm, about 200 to 1500 ppm, and about 200 to 1000 ppm.

[0118] The lubricant present on the surface of the heat-fusible resin layer 4 may be a lubricant exuded from the resin constituting the heat-fusible resin layer 4, or a lubricant applied to the surface of the heat-fusible resin layer 4.

[0119] Furthermore, the thickness of the heat-sealable resin layer 4 is not particularly limited as long as the heat-sealable resin layers are heat-sealed to each other to function as sealing the electricity storage device element, but from the viewpoint of more suitably exerting the effects of the invention of the present disclosure, the thickness is preferably about 15 μm or more, more preferably about 20 μm or more, even more preferably about 30 μm or more, and is preferably about 80 μm or less, more preferably about 70 μm or less, even more preferably about 60 μm or less, and preferred ranges include about 15 to 80 μm, about 15 to 70 μm, about 15 to 60 μm, about 20 to 80 μm, about 20 to 70 μm, about 20 to 60 μm, about 30 to 80 μm, about 30 to 70 μm, and about 30 to 60 μm.

[0120] (Method for producing the heat-fusible resin layer 4) The method for producing the heat-sealable resin layer 4 is not particularly limited as long as the heat-sealable resin layer 4 of the present disclosure can be obtained, and known or commonly used film-forming methods and lamination methods can be applied. The film can be produced by known film-forming methods and / or lamination methods, such as extrusion or co-extrusion, cast molding, T-die, cutting, and inflation. For example, a film constituting the heat-sealable resin layer 4 that has been produced in advance may be laminated via an adhesive layer, a molten resin composition may be laminated on a layer that has been produced in advance by extrusion or co-extrusion, a plurality of layers may be simultaneously produced and laminated by melt pressure bonding, or one or more resins may be applied and dried to coat another layer.

[0121] The thermally adhesive resin layer 4 may be formed by laminating layers included in the thermally adhesive resin layer 4 by extrusion or co-extrusion, using an extrusion coating method, or by laminating layers via an adhesive layer after film formation using an inflation method or a cast method. In the case of the extrusion coating method, lamination may be performed via an adhesive layer as necessary. Alternatively, a film for a water absorbing layer (or a sulfur-based gas absorbing layer) previously formed may be laminated and bonded via an adhesive layer laminated by an extrusion coating method, a dry lamination method, a non-solvent lamination method, or the like. Then, aging treatment may be performed as necessary.

[0122] For example, when laminating a film or the like by extrusion coating, first, the resin forming the film is heated and melted, and then expanded and stretched in the required width direction by a T-die to be (co)extruded in a curtain shape, and the molten resin is allowed to flow down onto the surface to be laminated and sandwiched between a rubber roll and a cooled metal roll, thereby simultaneously forming the layer, laminating and bonding to the surface to be laminated. When laminating by extrusion coating, the melt mass flow rate (MFR) of each resin component is preferably 0.2 to 50 g / 10 min, more preferably 0.5 to 30 g / 10 min. If the MFR is smaller or larger than the above range, the processability is likely to be poor. In this specification, the MFR is a value measured by a method conforming to JIS K7210.

[0123] When the inflation method is used, the melt mass flow rate (MFR) of the resin component is preferably 0.2 to 10 g / 10 min, more preferably 0.2 to 9.5 g / 10 min. If the MFR is smaller or larger than the above range, the processability is likely to be poor.

[0124] In addition, the surface of the heat-fusible resin layer 4 may be subjected to a desired surface treatment in advance, if necessary, in order to improve adhesion. For example, a corona-treated layer, an ozone-treated layer, a plasma-treated layer, an oxidation-treated layer, or the like may be formed by optionally performing a pretreatment such as a corona discharge treatment, an ozone treatment, a low-temperature plasma treatment using oxygen gas or nitrogen gas, a glow discharge treatment, or an oxidation treatment using chemicals. Alternatively, various coating layers such as a primer coating layer, an undercoat coating layer, an anchor coating layer, an adhesive layer, or a vapor deposition anchor coating layer may be optionally formed on the surface to form a surface treatment layer. For the various coating layers, for example, a resin composition containing a polyester resin, a polyamide resin, a polyurethane resin, an epoxy resin, a phenol resin, a (meth)acrylic resin, a polyvinyl acetate resin, a polyolefin resin such as polyethylene or polypropylene, or a copolymer or modified resin thereof, or a cellulose resin as the main component of the vehicle may be used.

[0125] The layers contained in the heat-fusible resin layer 4 can be further uniaxially or biaxially stretched by a conventionally known method, using a tenter system, a tubular system or the like, as necessary.

[0126] [Adhesive layer 5] In the packaging material for an electricity storage device of the present disclosure, the adhesive layer 5 is a layer that is provided, if necessary, between the barrier layer 3 (or the corrosion-resistant film) and the heat-sealable resin layer 4 in order to firmly bond them together.

[0127] The adhesive layer 5 is formed of a resin capable of bonding the barrier layer 3 and the heat-fusible resin layer 4. As the resin used to form the adhesive layer 5, for example, the same adhesive as exemplified for the adhesive layer 2 can be used.

[0128] In addition, from the viewpoint of firmly adhering the adhesive layer 5 and the heat-sealable resin layer 4, the resin used to form the adhesive layer 5 preferably contains a polyolefin skeleton, and examples thereof include the polyolefin, acid-modified polyolefin, cyclic polyolefin, and acid-modified cyclic polyolefin exemplified in the above-mentioned heat-sealable resin layer 4. On the other hand, from the viewpoint of firmly adhering the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 preferably contains an acid-modified polyolefin. Examples of the acid-modified component include dicarboxylic acids such as maleic acid, itaconic acid, succinic acid, and adipic acid, and their anhydrides, acrylic acid, and methacrylic acid, and maleic anhydride is most preferred in terms of ease of modification and versatility. In addition, from the viewpoint of the heat resistance of the exterior material for the electric storage device, the olefin component is preferably a polypropylene-based resin, and the adhesive layer 5 most preferably contains maleic anhydride-modified polypropylene.

[0129] When the resin used to form the adhesive layer 5 contains a polyolefin skeleton, the adhesive layer 5 preferably contains a resin containing a polyolefin skeleton as a main component, more preferably contains an acid-modified polyolefin as a main component, and even more preferably contains an acid-modified polypropylene as a main component. Here, the main component means that the content of the resin component contained in the adhesive layer 5 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, the adhesive layer 5 contains acid-modified polypropylene as a main component means that the content of the acid-modified polypropylene among the resin components contained in the adhesive layer 5 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0130] The resin constituting the adhesive layer 5 can be analyzed by, for example, infrared spectroscopy, gas chromatography mass spectrometry, etc., and the analysis method is not particularly limited, to determine whether the resin constituting the adhesive layer 5 contains a polyolefin skeleton. In addition, the resin constituting the adhesive layer 5 can be analyzed by, for example, infrared spectroscopy to determine whether the maleic anhydride-modified polyolefin contains an acid-modified polyolefin at a wave number of 1760 cm. -1 Nearby and wave number 1780cm -1 A peak derived from maleic anhydride is detected around this peak. However, if the degree of acid modification is low, the peak may be small and not detectable. In that case, analysis can be performed using nuclear magnetic resonance spectroscopy.

[0131] Furthermore, from the viewpoint of ensuring durability such as heat resistance and resistance to contents of the exterior material for an electricity storage device, and moldability while reducing the thickness, the adhesive layer 5 is more preferably a cured product of a resin composition containing an acid-modified polyolefin and a curing agent. Preferred examples of the acid-modified polyolefin include those mentioned above.

[0132] The adhesive layer 5 is preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group, and is particularly preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group. The adhesive layer 5 is preferably at least one selected from the group consisting of polyurethane, polyester, and epoxy resin, and more preferably contains polyurethane and epoxy resin. As the polyester, for example, an ester resin generated by the reaction of an epoxy group with a maleic anhydride group, and an amide ester resin generated by the reaction of an oxazoline group with a maleic anhydride group are preferable. In addition, when unreacted substances of a curing agent such as a compound having an isocyanate group, a compound having an oxazoline group, or an epoxy resin remain in the adhesive layer 5, the presence of the unreacted substances can be confirmed by a method selected from, for example, infrared spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), etc.

[0133] In addition, from the viewpoint of further increasing the adhesion between the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 is preferably a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of an oxygen atom, a heterocycle, a C=N bond, and a COC bond. Examples of the curing agent having a heterocycle include a curing agent having an oxazoline group and a curing agent having an epoxy group. Examples of the curing agent having a C=N bond include a curing agent having an oxazoline group and a curing agent having an isocyanate group. Examples of the curing agent having a COC bond include a curing agent having an oxazoline group and a curing agent having an epoxy group. The fact that the adhesive layer 5 is a cured product of a resin composition containing these curing agents can be confirmed by, for example, gas chromatography mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF-SIMS), X-ray photoelectron spectroscopy (XPS), or other methods.

[0134] The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively increasing the adhesion between the barrier layer 3 and the adhesive layer 5, a polyfunctional isocyanate compound is preferably used. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of polyfunctional isocyanate-based curing agents include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymerized or nurated products thereof, mixtures thereof, and copolymers with other polymers. In addition, adducts, biurets, isocyanurates, etc. are also included.

[0135] The content of the compound having an isocyanate group in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, in the resin composition constituting the adhesive layer 5. This makes it possible to effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5.

[0136] The compound having an oxazoline group is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of the compound having an oxazoline group include those having a polystyrene main chain and those having an acrylic main chain. In addition, examples of commercially available products include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

[0137] The proportion of the compound having an oxazoline group in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, in the resin composition constituting the adhesive layer 5. This makes it possible to effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5.

[0138] An example of a compound having an epoxy group is an epoxy resin. The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure by the epoxy group present in the molecule, and a known epoxy resin can be used. The weight average molecular weight of the epoxy resin is preferably about 50 to 2000, more preferably about 100 to 1000, and even more preferably about 200 to 800. In the present disclosure, the weight average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) under conditions using polystyrene as a standard sample.

[0139] Specific examples of epoxy resins include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, bisphenol F glycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, etc. The epoxy resins may be used alone or in combination of two or more.

[0140] The ratio of the epoxy resin in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, in the resin composition constituting the adhesive layer 5. This can effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5.

[0141] The polyurethane is not particularly limited, and any known polyurethane can be used. The adhesive layer 5 may be, for example, a cured product of a two-component curing polyurethane.

[0142] The proportion of polyurethane in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, in the resin composition constituting the adhesive layer 5. This makes it possible to effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5 in an atmosphere containing a component that induces corrosion of the barrier layer, such as an electrolyte solution.

[0143] In addition, when the adhesive layer 5 is a cured product of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin, the acid-modified polyolefin functions as a main agent, and the compound having an isocyanate group, the compound having an oxazoline group, and the compound having an epoxy group each function as a curing agent.

[0144] The adhesive layer 5 may contain a modifier having a carbodiimide group.

[0145] When the adhesive layer 5 is laminated with the barrier layer 3, the heat-sealable resin layer 4, or the like to produce the exterior packaging material 10 for an electricity storage device of the present disclosure, a preformed resin film may be used as the adhesive layer 5. The heat-sealable resin that forms the adhesive layer 5 may be formed into a film on the surface of the barrier layer 3, the heat-sealable resin layer 4, or the like by extrusion molding, coating, or the like, to form the adhesive layer 5 from a resin film.

[0146] The thickness of the adhesive layer 5 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, or about 5 μm or less. The thickness of the adhesive layer 5 is preferably about 0.1 μm or more, or about 0.5 μm or more. The thickness of the adhesive layer 5 is preferably in the range of about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, about 0.1 to 5 μm, about 0.5 to 50 μm, about 0.5 to 40 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, or about 0.5 to 5 μm. More specifically, in the case of the adhesive exemplified in the adhesive layer 2 or a cured product of an acid-modified polyolefin and a curing agent, the thickness is preferably about 1 to 10 μm, more preferably about 1 to 5 μm. When a resin exemplified for the heat-fusible resin layer 4 is used, the thickness is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. When the adhesive layer 5 is an adhesive exemplified for the adhesive layer 2 or a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, the adhesive layer 5 can be formed, for example, by applying the resin composition and curing it by heating or the like. When a resin exemplified for the heat-fusible resin layer 4 is used, the adhesive layer 5 can be formed, for example, by extrusion molding the heat-fusible resin layer 4 and the adhesive layer 5.

[0147] In the exterior material for a power storage device of the present disclosure, the layer (at least one layer among the heat-sealable resin layer 4, the adhesive layer 5 provided as required, etc.) inside the barrier layer 3 may contain at least one of a water absorbing agent and a sulfur-based gas absorbent. In the present disclosure, a layer containing a water absorbing material may be referred to as a "water absorbing layer". In addition, in the present disclosure, a layer containing a sulfur-based gas absorbent may be referred to as a "sulfur-based gas absorbing layer". When a water absorbing agent and a sulfur-based gas absorbent are contained in a layer inside the barrier layer 3, the water absorbing agent and the sulfur-based gas absorbent may be contained in the same layer or in different layers. When the layer inside the barrier layer 3 is composed of two or more layers, it is preferable that the sulfur-based gas absorbent is contained in a layer not containing a water absorbing agent to constitute the sulfur-based gas absorbing layer.

[0148] The moisture to be absorbed by the water absorbing agent is gaseous and / or liquid moisture. The moisture to be absorbed generates various outgases when absorbed, for example, in a solid electrolyte type lithium ion battery. Examples of the sulfur-based gas to be absorbed by the sulfur-based gas absorbent include hydrogen sulfide, dimethyl sulfide, methyl mercaptan, and sulfur oxides represented by SOx. The sulfur-based gas is a component of the outgas (for example, generated when the power storage device is an all-solid-state battery using a sulfide-based inorganic solid electrolyte or when the power storage device is a lithium secondary battery using lithium sulfur in the positive electrode).

[0149] The water absorbing agent contained in the water absorbing layer is not particularly limited as long as it is dispersed in the resin and exhibits water absorption. For example, from the viewpoint of stability over time in the power storage device, an inorganic water absorbing agent can be suitably used. Specific examples of preferred inorganic water absorbing agents include calcium oxide, anhydrous magnesium sulfate, magnesium oxide, calcium chloride, zeolite, aluminum oxide, silica gel, alumina gel, and calcined alum. In general, inorganic chemical water absorbing agents have a higher water absorption effect than inorganic physical water absorbing agents, can reduce the content, and can easily achieve sufficient water absorption and heat fusion in a single layer. Among inorganic chemical water absorbing agents, calcium oxide, anhydrous magnesium sulfate, and magnesium oxide are particularly preferred because they have little re-release of moisture, high stability over time in a low humidity state inside the package, and have an absolute dry effect. The absolute dry effect refers to the effect of absorbing water until the relative humidity is near 0%, and the humidity control effect refers to the effect of absorbing water when the humidity is high and releasing moisture when the humidity is low to keep the humidity constant.

[0150] The content of the resin in the water absorbing layer is, for example, 50% by mass or more, preferably 55% by mass or more, and more preferably 60% by mass or more.

[0151] The content of the water absorbing agent contained in the water absorption layer is not particularly limited as long as the effects of the present disclosure are achieved, and is preferably at least about 0.5 parts by mass, more preferably at least about 2 parts by mass, and even more preferably at least about 3 parts by mass, relative to 100 parts by mass of the resin contained in the water absorption layer, and is preferably not more than about 50 parts by mass, more preferably not more than about 45 parts by mass, and even more preferably not more than 40 parts by mass. Preferred ranges of the content include about 0.5 to 50 parts by mass, about 0.5 to 45 parts by mass, about 0.5 to 40 parts by mass, about 2 to 50 parts by mass, about 2 to 45 parts by mass, about 2 to 40 parts by mass, about 3 to 50 parts by mass, about 3 to 45 parts by mass, and about 3 to 40 parts by mass.

[0152] The sulfur-based gas absorbent preferably contains a sulfur-based gas physical absorbent and / or a sulfur-based gas chemical absorbent. By using various sulfur-based gas absorbents in combination, for example, by using a sulfur-based gas physical absorbent and a sulfur-based gas chemical absorbent in combination, it becomes possible to easily absorb various types of sulfur-based gases. The sulfur-based gas absorbent is used, for example, in the form of a powder. The maximum particle size of the sulfur-based gas absorbent is preferably 20 μm or less, and the number average particle size of the powder is preferably 0.1 μm or more, 1.0 μm or more, and is preferably 15 μm or less, 10 μm or less, or 8 μm or less, and preferred ranges include about 0.1 to 15 μm, about 0.1 to 10 μm, about 0.1 to 8 μm, about 1 to 15 μm, about 1 to 10 μm, and about 1 to 8 μm. If the number average particle size is smaller than the above range, the sulfur-based gas absorbent will be prone to aggregation, and if the number average particle size is larger than the above range, the homogeneity of the sulfur-based gas absorbing film may be poor, and the surface area of ​​the sulfur-based gas absorbent may be reduced, resulting in poor sulfur-based gas absorption.

[0153] (Sulfur gas physical absorbent) The sulfur-based gas physical absorbent is a gas absorbent that has the function of physically absorbing the sulfur-based gas to be absorbed. The sulfur-based gas physical absorbent is SiO 2 / Al 2 O 3 It is preferable to contain one or more kinds selected from the group consisting of hydrophobic zeolite, bentonite and sepiolite in a molar ratio of 1 / 1 to 2000 / 1.

[0154] Hydrophobic zeolite is a zeolite with excellent absorption of low polarity molecules such as sulfur gases, and has a porous structure. Generally, zeolite is composed of SiO 2 / Al 2 O 3 The higher the molar ratio of SiO, the higher the hydrophobicity. Higher hydrophobicity makes it easier to absorb low polarity molecules such as sulfur-based gases, and conversely, it has a lower affinity with highly polar molecules such as water, making it difficult to absorb them. 2 / Al 2 O 3 The molar ratio is preferably 30 / 1 to 10000 / 1, more preferably 35 / 1 to 9000 / 1, and even more preferably 40 / 1 to 8500 / 1. Hydrophobic zeolite has high heat resistance and can maintain its absorption effect even when exposed to high temperatures of 230° C. or higher. In the present invention, a hydrophobic zeolite having a molar ratio in the above range is preferably used from the viewpoint of the balance between sulfur-based gas absorption ability and ease of availability.

[0155] Bentonite is an inorganic substance that is mainly composed of the clay mineral montmorillonite, contains a large amount of layered aluminum phyllosilicate, and contains minerals such as quartz and feldspar as impurities. For example, Na + Bentonite containing a lot of Na ions and Ca 2+ There are Ca-type bentonites that contain a lot of ions, and activated bentonites that are made by adding a few wt% of sodium carbonate to Ca-type bentonite to artificially convert it to Na-type bentonite.

[0156] Sepiolite is a clay mineral whose main component is hydrous magnesium silicate. Its general chemical composition is Mg 8 S 12 O 30 (OH 2 ) 4 (OH) 4 6~8H 2 It has a porous structure and is represented by O. From the viewpoint of availability, the pH (3% suspension) is preferably 8.0 to 9.0, and more preferably 8.9 to 9.3.

[0157] (Sulfur gas chemical absorbent) The sulfur-based gas chemical absorbent is a gas absorbent that has the function of chemically absorbing or decomposing the sulfur-based gas of the gas to be absorbed. And, because it is chemically absorbed or decomposed, it is not easily affected by water, etc., and once absorbed, the sulfur-based gas molecules are not easily desorbed, so that it can be efficiently absorbed. In addition, the decomposition product is absorbed by the sulfur-based gas physical absorbent or the sulfur-based gas chemical absorbent. The sulfur-based gas chemical absorbent preferably contains one or more selected from the group consisting of inorganic matter carrying a metal oxide, glass mixed with a metal, and glass mixed with a metal ion. The metal oxide in the inorganic matter carrying a metal oxide preferably contains one or more selected from the group consisting of CuO, ZnO, and AgO. In addition, the inorganic matter to be supported is preferably an inorganic porous body such as zeolite. The metal in the glass containing a metal, or the metal species of the metal ions in the glass containing a metal ion, preferably includes one or more species selected from the group consisting of Ca, Mg, Na, Cu, Zn, Ag, Pt, Au, Fe, Al, and Ni.

[0158] The content of the sulfur-based gas absorbent contained in the sulfur-based gas absorbing layer is not particularly limited as long as it absorbs sulfur-based gases, and is preferably about 5 parts by mass or more, more preferably about 6 parts by mass or more, and even more preferably about 7 parts by mass or more, relative to 100 parts by mass of the resin contained in the sulfur-based gas absorbing layer. Also, it is preferably about 60 parts by mass or less, more preferably about 55 parts by mass or less, more preferably about 50 parts by mass or less, and even more preferably about 30 parts by mass or less. The preferred range of the content is about 5 to 60 parts by mass, about 5 to 55 parts by mass, about 5 to 50 parts by mass, about 5 to 30 parts by mass, about 6 to 60 parts by mass, about 6 to 55 parts by mass, about 6 to 50 parts by mass, about 6 to 30 parts by mass, about 7 to 60 parts by mass, about 7 to 55 parts by mass, about 7 to 50 parts by mass, and about 7 to 30 parts by mass.

[0159] [Surface coating layer 6] The exterior material for an electricity storage device according to the present disclosure may have a surface coating layer 6 on the substrate layer 1 (the side of the substrate layer 1 opposite to the barrier layer 3) as necessary, for the purpose of improving at least one of design, electrolyte resistance, scratch resistance, formability, etc. The surface coating layer 6 is a layer located on the outermost layer side of the exterior material for an electricity storage device when an electricity storage device is assembled using the exterior material for an electricity storage device.

[0160] The surface coating layer 6 may be made of, for example, a resin such as polyvinylidene chloride, polyester, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, or phenol resin, or a modified product of these resins. It may also be a copolymer of these resins or a modified product of the copolymer. Furthermore, it may be a mixture of these resins. The resin is preferably a curable resin. That is, the surface coating layer 6 is preferably made of a cured product of a resin composition containing a curable resin.

[0161] When the resin forming the surface coating layer 6 is a curable resin, the resin may be either a one-component curable type or a two-component curable type, but is preferably a two-component curable type. Examples of two-component curable resins include two-component curable polyurethane, two-component curable polyester, and two-component curable epoxy resin. Among these, two-component curable polyurethane is preferred.

[0162] Examples of two-component curing polyurethane include polyurethanes containing a first agent containing a polyol compound and a second agent containing an isocyanate compound. Preferably, two-component curing polyurethanes are made of a polyol such as polyester polyol, polyether polyol, and acrylic polyol as the first agent, and an aromatic or aliphatic polyisocyanate as the second agent. Examples of polyurethanes include polyurethane compounds in which a polyol compound and an isocyanate compound have been reacted in advance, and polyurethanes containing an isocyanate compound. Examples of polyurethanes include polyurethane compounds in which a polyol compound and an isocyanate compound have been reacted in advance, and polyurethanes containing a polyol compound. Examples of polyurethanes include polyurethanes in which a polyurethane compound in which a polyol compound and an isocyanate compound have been reacted in advance is cured by reacting it with moisture in the air or the like. As the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group on the side chain in addition to the hydroxyl group at the end of the repeating unit. As the second agent, aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds are included. Examples of isocyanate compounds include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and naphthalene diisocyanate (NDI). In addition, examples of the isocyanate compounds include polyfunctional isocyanate modified compounds made from one or more of these diisocyanates. In addition, a polymer (e.g., a trimer) can also be used as the polyisocyanate compound. Examples of such polymers include adducts, biurets, and nurates. In addition, an aliphatic isocyanate compound refers to an isocyanate having an aliphatic group and no aromatic ring, an alicyclic isocyanate compound refers to an isocyanate having an alicyclic hydrocarbon group, and an aromatic isocyanate compound refers to an isocyanate having an aromatic ring.The surface coating layer 6 is formed from polyurethane, thereby imparting excellent electrolyte resistance to the exterior material for an electricity storage device.

[0163] The surface coating layer 6 may contain additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, antistatic agents, and pigments, depending on the functionality to be provided to the surface of the surface coating layer 6, at least on the surface and / or inside the surface coating layer 6. Examples of additives include fine particles having an average particle size of about 0.5 nm to 5 μm. The average particle size of the additive is the median size measured by a laser diffraction / scattering type particle size distribution measuring device.

[0164] The additive may be either inorganic or organic. The shape of the additive is not particularly limited, and examples of the shape include spherical, fibrous, plate-like, amorphous, and scaly.

[0165] Specific examples of additives include talc, silica, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, high melting point nylon, acrylate resin, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel, etc. The additives may be used alone or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferable from the viewpoint of dispersion stability and cost. In addition, the additives may be subjected to various surface treatments such as insulation treatment and high dispersibility treatment.

[0166] The method for forming the surface coating layer 6 is not particularly limited, and examples thereof include a method for applying a resin that forms the surface coating layer 6. When an additive is blended into the surface coating layer 6, a resin mixed with the additive may be applied.

[0167] In the present disclosure, from the viewpoint of improving the formability of the exterior material for a power storage device, it is preferable that a lubricant is present on at least one of the surface and the inside of the surface coating layer 6. The lubricant is not particularly limited, but is preferably an amide-based lubricant. Specific examples of amide-based lubricants include, for example, saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of saturated fatty acid amides include lauric acid amides, palmitic acid amides, stearic acid amides, behenic acid amides, and hydroxystearic acid amides. Specific examples of unsaturated fatty acid amides include oleic acid amides and erucic acid amides. Specific examples of substituted amides include N-oleyl palmitic acid amides, N-stearyl stearic acid amides, N-stearyl oleic acid amides, N-oleyl stearic acid amides, and N-stearyl erucic acid amides. Specific examples of methylol amides include methylol stearic acid amides. Specific examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, N,N'-distearyl sebacic acid amide, etc. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipic acid amide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamide ethyl stearate, etc. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N,N'-distearylisophthalic acid amide.The lubricant may be used alone or in combination of two or more kinds, and it is preferable to use a combination of two or more kinds.

[0168] When a lubricant is present on the surface of the surface coating layer 6, the amount of the lubricant is not particularly limited, but may be, for example, about 3 mg / m 2 or more, preferably about 4 mg / m 2 More than about 5mg / m 2 The amount of lubricant present on the surface of the surface coating layer 6 is, for example, about 15 mg / m 2 Less than or equal to about 14 mg / m 2 Below, about 10mg / m 2 The preferred range of the amount of lubricant present on the surface of the surface coating layer 6 is 3 to 15 mg / m 2 degree, 3~14mg / m 2 degree, 3~10mg / m 2 degree, 4~15mg / m 2 degree, 4~14mg / m 2 degree, 4~10mg / m 2 degree, 5~15mg / m 2 degree, 5~14mg / m 2 degree, 5~10mg / m 2 The degree of

[0169] The lubricant present on the surface of the surface coating layer 6 may be a lubricant exuded from the resin constituting the surface coating layer 6, or a lubricant applied to the surface of the surface coating layer 6.

[0170] The exterior material for an electricity storage device can be colored by including a colorant in the surface coating layer 6. Known colorants such as pigments and dyes can be used as the colorant. Only one type of colorant may be used, or two or more types may be mixed together.

[0171] The type of pigment is not particularly limited, and examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments. Examples of inorganic pigments include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments. Other examples include fine mica powder and fish scale foil.

[0172] Among colorants, carbon black is preferred in order to give the exterior material for an electricity storage device a black appearance, and mica is preferred from the viewpoint of dissipating heat generated from the electricity storage device.

[0173] The average particle size of the pigment is not particularly limited and may be, for example, about 0.03 to 5 μm, and preferably about 0.05 to 2 μm. The average particle size of the pigment is the median size measured by a laser diffraction / scattering type particle size distribution measuring device.

[0174] The content of the colorant in the surface coating layer 6 is not particularly limited as long as the exterior material for an electricity storage device is colored, and may be, for example, about 5 to 60 mass %, and preferably about 10 to 40 mass %.

[0175] The thickness of the surface coating layer 6 is not particularly limited as long as the surface coating layer 6 exhibits the above-mentioned functions, and may be, for example, about 0.5 to 10 μm, and preferably about 1 to 5 μm.

[0176] 3. Manufacturing method for exterior material for power storage device The manufacturing method of the exterior material for an electricity storage device is not particularly limited, so long as a laminate is obtained in which each layer of the exterior material for an electricity storage device of the present disclosure is laminated, and examples include a method including a step of laminating at least a base material layer 1, a barrier layer 3, and a heat-sealable resin layer 4 in this order.

[0177] An example of a method for producing an exterior material for an electricity storage device according to the present disclosure is as follows. First, a laminate (hereinafter, sometimes referred to as "laminate A") is formed in which a base layer 1, an adhesive layer 2, and a barrier layer 3 are laminated in this order. Specifically, the laminate A can be formed by a dry lamination method in which an adhesive used for forming the adhesive layer 2 is applied to the base layer 1 or to the barrier layer 3, the surface of which has been chemically treated as necessary, by a coating method such as gravure coating or roll coating, and then dried, and the barrier layer 3 or base layer 1 is laminated thereon, and the adhesive layer 2 is cured.

[0178] Next, the heat-sealable resin layer 4 is laminated on the barrier layer 3 of the laminate A. When the heat-sealable resin layer 4 is directly laminated on the barrier layer 3, the heat-sealable resin layer 4 may be laminated on the barrier layer 3 of the laminate A by a method such as a thermal lamination method or an extrusion lamination method. When an adhesive layer 5 is provided between the barrier layer 3 and the heat-sealable resin layer 4, the adhesive layer 5 and the heat-sealable resin layer 4 may be laminated, for example, by (1) an extrusion lamination method, (2) a thermal lamination method, (3) a sandwich lamination method, or (4) a dry lamination method. Examples of the (1) extrusion lamination method include a method of laminating the adhesive layer 5 and the heat-sealable resin layer 4 by extruding them onto the barrier layer 3 of the laminate A (co-extrusion lamination method, tandem lamination method), and the like. Examples of the (2) thermal lamination method include a method of forming a laminate in which an adhesive layer 5 and a heat-sealable resin layer 4 are laminated separately, and laminating the laminate on the barrier layer 3 of the laminate A, or a method of forming a laminate in which an adhesive layer 5 is laminated on the barrier layer 3 of the laminate A, and laminating the laminate on the heat-sealable resin layer 4. Examples of the (3) sandwich lamination method include a method of laminating the laminate A and the heat-sealable resin layer 4 via the adhesive layer 5 while pouring a molten adhesive layer 5 between the barrier layer 3 of the laminate A and the heat-sealable resin layer 4 previously formed into a sheet. Examples of the (4) dry lamination method include a method of coating the barrier layer 3 of the laminate A with an adhesive for forming the adhesive layer 5 as a solution, drying the adhesive, or baking the adhesive, and laminating the heat-sealable resin layer 4 previously formed into a sheet on the adhesive layer 5.

[0179] When the surface coating layer 6 is provided, the surface coating layer 6 is laminated on the surface of the base layer 1 opposite to the barrier layer 3. The surface coating layer 6 can be formed, for example, by applying the above-mentioned resin for forming the surface coating layer 6 to the surface of the base layer 1. The order of the step of laminating the barrier layer 3 on the surface of the base layer 1 and the step of laminating the surface coating layer 6 on the surface of the base layer 1 is not particularly limited. For example, after forming the surface coating layer 6 on the surface of the base layer 1, the barrier layer 3 may be formed on the surface of the base layer 1 opposite to the surface coating layer 6.

[0180] As described above, a laminate is formed which includes, in this order, the optional surface coating layer 6 / the base material layer 1 / the optional adhesive layer 2 / the barrier layer 3 / the optional adhesive layer 5 / the heat-sealable resin layer 4. In order to strengthen the adhesion of the optional adhesive layer 2 and the optional adhesive layer 5, the laminate may be subjected to a heat treatment.

[0181] In the exterior packaging material for an electricity storage device, each layer constituting the laminate may be subjected to a surface activation treatment such as corona treatment, blast treatment, oxidation treatment, ozone treatment, etc., as necessary, to improve the processability. For example, by subjecting the surface of the base layer 1 opposite to the barrier layer 3 to corona treatment, the printability of the ink on the surface of the base layer 1 can be improved.

[0182] 4. Applications of exterior materials for energy storage devices The exterior material for an electricity storage device according to the present disclosure is used in a package for hermetically housing an electricity storage device element such as a positive electrode, a negative electrode, and an electrolyte. That is, an electricity storage device can be formed by housing an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte in a package formed by the exterior material for an electricity storage device according to the present disclosure. In other words, an electricity storage device can be formed by wrapping an electricity storage device element with the exterior material for an electricity storage device according to the present disclosure.

[0183] Specifically, an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte is covered with the exterior material for an electricity storage device of the present disclosure in such a manner that a flange portion (a region where the heat-sealable resin layers contact each other) can be formed on the periphery of the electricity storage device element with the metal terminals connected to each of the positive electrode and the negative electrode protruding outward, and the heat-sealable resin layers of the flange portion are heat-sealed to provide an electricity storage device using the exterior material for an electricity storage device. When an electricity storage device element is housed in a package formed with the exterior material for an electricity storage device of the present disclosure, the package is formed so that the heat-sealable resin portion of the exterior material for an electricity storage device of the present disclosure faces inside (the surface in contact with the electricity storage device element). The heat-sealable resin layers of two electrical storage device exterior materials may be stacked facing each other, and the peripheral portions of the stacked electrical storage device exterior materials may be heat-sealed to form a package. Alternatively, as shown in the example of FIG. 5, one electrical storage device exterior material may be folded back and stacked, and the peripheral portions may be heat-sealed to form a package. When the materials are folded back and stacked, as shown in the example of FIG. 5, the sides other than the folded side may be heat-sealed to form a package by sealing on three sides, or the materials may be folded back and sealed on four sides so that a flange portion can be formed. When the innermost layer and the outermost layer of the electrical storage device exterior material are heat-sealable resin layers, the package may be formed by heat-sealing the innermost heat-sealable resin layer and the outermost heat-sealable resin layer.

[0184] The electric storage device element may be sealed by a lid body in addition to the exterior material for the electric storage device. That is, the exterior material for the electric storage device and the lid body constitute an exterior body (exterior body for the electric storage device) that seals the electric storage device element. For example, the electric storage device element may be accommodated inside the exterior material for the electric storage device configured in a cylindrical shape, and the opening may be closed by the lid body. In another example, the electric storage device element connected to the lid body may be accommodated inside the exterior material for the electric storage device configured in a cylindrical shape so that an opening is formed, and the opening may be closed by the lid body. The lid body and the exterior material for the electric storage device are preferably joined by any means. From the viewpoint of reducing the dead space between the electric storage device element and the exterior material for the electric storage device in order to improve the volumetric energy density of the electric storage device, the exterior material for the electric storage device is preferably wrapped around the electric storage device element and the lid body.

[0185] The lid body can be formed, for example, from a resin molded product, a metal molded product, an exterior material for an electricity storage device, or a combination thereof. In the present disclosure, when the lid body is expressed as a resin molded product, the lid body does not include an embodiment in which the lid body is composed only of a film defined by JIS K6900-1994 [Plastic terminology]. When the lid body is a metal molded product, the lid body also functions as a metal terminal, so that the metal terminal can be omitted. The lid body may be composed of a resin material and a conductive material.

[0186] The exterior material for an electric storage device of the present disclosure can be suitably used for an electric storage device such as a battery (including a condenser, a capacitor, etc.). The exterior material for an electric storage device of the present disclosure may be used for either a primary battery or a secondary battery, but is preferably used for a secondary battery. The type of secondary battery to which the exterior material for an electric storage device of the present disclosure is applied is not particularly limited, and examples thereof include lithium ion batteries, lithium ion polymer batteries, all-solid batteries, semi-solid batteries, quasi-solid batteries, polymer batteries, all-resin batteries, lead-acid batteries, nickel-hydrogen batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, capacitors, etc. Among these secondary batteries, examples of suitable applications of the exterior material for an electric storage device of the present disclosure include lithium ion batteries, lithium ion polymer batteries, and all-solid batteries. EXAMPLES

[0187] The present disclosure will be described in detail below with reference to examples and comparative examples. However, the present disclosure is not limited to the examples.

[0188] <Manufacture of exterior materials for power storage devices> Example 1 As the substrate layer, a polyethylene terephthalate film (thickness 25 μm) was prepared with a corona treatment applied to the bonding surface side. As the barrier layer, an aluminum alloy foil (JIS H4160:1994 A8021H-O, thickness 60 μm) was prepared. As the heat-sealable resin layer (thickness 40 μm), a homopolybutylene terephthalate film (homoPBT: (constituent units are terephthalic acid and 1,4-butanediol)) was used. Next, a two-component curing urethane adhesive (polyester polyol and alicyclic isocyanate compound) was used to bond the substrate layer and the barrier layer by a dry lamination method, and a laminate in which the substrate layer / adhesive layer / barrier layer were laminated in this order was produced.

[0189] Next, the barrier layer side of the obtained laminate was adhered to the heat-sealable resin layer by a dry lamination method using a two-liquid curing urethane adhesive (polyester polyol and alicyclic isocyanate compound), and an adhesive layer (4 μm) / heat-sealable resin layer was laminated on the barrier layer. Next, the obtained laminate was aged and heated to obtain an exterior material for a power storage device consisting of a laminate in which the base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0190] Example 2 An exterior material for a power storage device was obtained in the same manner as in Example 1, except that an aluminum alloy foil (JIS H4160:1994 A8021H-O, thickness 40 μm) was used as the barrier layer, and the following copolymer polybutylene terephthalate film was used as the heat-sealable resin layer (thickness 40 μm). The laminate was made of a base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer in this order.

[0191] The heat-sealable resin layer of Example 2 was formed by a copolymerized polybutylene terephthalate film (copolymerized PBT). The copolymerized polybutylene terephthalate film has two structural units, terephthalic acid and 1,4-butanediol, which form the main component polybutylene terephthalate structure, and further, a polyester structure B is block-polymerized to the polybutylene terephthalate structure as a secondary component. The polyester structure B is a structure in which dodecanedioic acid (dodecanedioic acid) is introduced into the resin as a third structural unit by copolymerization with the 1,4-butanediol. Therefore, the resin forming the film includes a polybutylene terephthalate structure (terephthalic acid and 1,4-butanediol as monomer units are two structural units) and a polyester structure B (dodecanedioic acid as a monomer unit is one structural unit), and has a structure in which a total of three structural units are copolymerized. The copolymer polybutylene terephthalate film of the heat-sealable resin layer contains 10 mass% of polyester structure B (the molar ratio of terephthalic acid, 1,4-butanediol, and dodecanedioic acid as monomer units (terephthalic acid residues:1,4-butanediol residues:dodecanedioic acid residues) is 100:113:12).

[0192] Example 3 An exterior material for a power storage device was obtained in the same manner as in Example 2, except that an aluminum alloy foil (JIS H4160:1994 A8021H-O, thickness 60 μm) was used as the barrier layer, and the laminate was formed by laminating a base layer / adhesive layer / barrier layer / adhesive layer / thermally adhesive resin layer in this order.

[0193] Example 4 An exterior material for a storage battery device was obtained in the same manner as in Example 3, except that a polyethylene terephthalate film (thickness 38 μm) with the bonding surface side thereof subjected to corona treatment was used as the base material layer, and the laminate was formed by laminating the base material layer / adhesive layer / barrier layer / adhesive layer / thermally adhesive resin layer in this order.

[0194] Example 5 An exterior material for a storage battery device was obtained in the same manner as in Example 3, except that a polyethylene terephthalate film (thickness 6 μm) with the bonding surface side thereof subjected to corona treatment was used as the base material layer, and the laminate was formed by laminating a base material layer / adhesive layer / barrier layer / adhesive layer / thermally adhesive resin layer in this order.

[0195] Example 6 An exterior material for a storage battery device was obtained in the same manner as in Example 3, except that a polyethylene terephthalate film (thickness 12 μm) with the bonding surface side thereof subjected to corona treatment was used as the base material layer, and the laminate was formed by laminating a base material layer / adhesive layer / barrier layer / adhesive layer / thermally adhesive resin layer in this order.

[0196] Example 7 An exterior material for a power storage device was obtained in the same manner as in Example 1, except that an aluminum alloy foil (JIS H4160:1994 A8021H-O, thickness 40 μm) was used as the barrier layer, and the following copolymer polybutylene terephthalate film was used as the heat-sealable resin layer (thickness 40 μm). The laminate was made of a base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer in this order.

[0197] The heat-sealable resin layer of Example 7 was formed by a copolymerized polybutylene terephthalate film (copolymerized PBT). The copolymerized polybutylene terephthalate film has two structural units, terephthalic acid and 1,4-butanediol, which form the main component polybutylene terephthalate structure, and further, a polyester structure B is block-polymerized as a secondary component to the polybutylene terephthalate structure. The polyester structure B is a structure in which polyether is introduced into the resin by copolymerization as a third structural unit. Therefore, the resin forming the film includes a polybutylene terephthalate structure (terephthalic acid and 1,4-butanediol as monomer units are two structural units) and a polyester structure B (polyether as a monomer unit is one structural unit), and has a structure in which a total of three structural units are copolymerized. The copolymer polybutylene terephthalate film of the heat-sealable resin layer contains 20 mass% of polyester structure B (the molar ratio of terephthalic acid, 1,4-butanediol, and polyether as monomer units (terephthalic acid residues:1,4-butanediol residues:polyether residues) is 100:85:15).

[0198] Comparative Example 1 A laminate film was prepared as the substrate layer, in which a polyethylene terephthalate film (thickness 12 μm) and a nylon film (thickness 12 μm) were bonded with a two-component curing urethane adhesive (polyester polyol and aromatic isocyanate compound, thickness after curing was 3 μm). In addition, an aluminum alloy foil (JIS H4160:1994 A8021H-O, thickness 60 μm) was prepared as the barrier layer. Next, the nylon film side of the substrate layer and the barrier layer were bonded by a dry lamination method using the two-component curing urethane adhesive (polyester polyol and aromatic isocyanate compound), to produce a laminate in which the substrate layer / adhesive layer / barrier layer were laminated in this order.

[0199] Next, the maleic anhydride-modified polypropylene as the adhesive layer and the polypropylene as the heat-sealable resin layer were co-extruded, and the adhesive layer (40 μm) / heat-sealable resin layer (40 μm) were laminated on the barrier layer. Next, the resulting laminate was aged and heated to obtain an exterior material for a power storage device consisting of a laminate in which the base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0200] Comparative Example 2 As the substrate layer, a polyethylene terephthalate film (thickness 25 μm) was prepared with a corona treatment applied to the bonding surface side. As the barrier layer, an aluminum alloy foil (JIS H4160:1994 A8021H-O, thickness 60 μm) was prepared. Next, a two-component curing urethane adhesive (polyester polyol and alicyclic isocyanate compound) was used to bond the substrate layer and the barrier layer by a dry lamination method, and a laminate in which the substrate layer / adhesive layer / barrier layer were laminated in this order was produced.

[0201] Next, the maleic anhydride-modified polypropylene as the adhesive layer and the polypropylene as the heat-sealable resin layer were co-extruded, and the adhesive layer (40 μm) / heat-sealable resin layer (40 μm) were laminated on the barrier layer. Next, the resulting laminate was aged and heated to obtain an exterior material for a power storage device consisting of a laminate in which the base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0202] Comparative Example 3 An exterior material for a storage battery device was obtained consisting of a laminate in which a base layer / adhesive layer / barrier layer / adhesive layer / thermal adhesive resin layer were laminated in this order in the same manner as in Example 7, except that a homopolybutylene terephthalate film (homoPBT: (constituent units are two types, terephthalic acid and 1,4-butanediol), thickness 40 μm) was used as the thermal adhesive resin layer.

[0203] Comparative Example 4 An exterior material for a power storage device was obtained consisting of a laminate in which a base layer / adhesive layer / barrier layer / adhesive layer / thermal adhesive resin layer were laminated in this order in the same manner as in Example 1, except that a homopolybutylene terephthalate film (homoPBT: (constituent units are two types, terephthalic acid and 1,4-butanediol), thickness 25 μm) was used as the thermal adhesive resin layer.

[0204] <Measurement of tensile breaking strength> The tensile breaking strength of the electrical storage device packaging material was measured by the following method. The results are shown in Table 1. The tensile breaking strength in the MD direction of the electrical storage device packaging material was measured using a tensile tester in accordance with the method specified in JIS K7127:1999. The measurement conditions were as follows: a dumbbell No. 7 sample shape, a gauge length of 10 mm, a pulling speed of 0.5 mm / min, and a test environment of 120°C, and the average value was measured three times.

[0205] <Creep resistance measurement> The creep resistance of the exterior material for a power storage device was measured by the following method. The results are shown in Table 1. The exterior material for a power storage device was cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half so that the heat-sealing resin layer was on the inside, and heat-sealed so that the thickness of the heat-sealing resin layer was in the range of 60% to 95% of that before sealing (that is, the exterior material for a power storage device was cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half in the MD direction at the middle position in the MD direction so that the heat-sealing resin layers faced each other, and heat-sealed with a 7 mm heat seal bar at a position 10 mm back from the fold in the MD direction so that the thickness of the heat-sealing resin layer was in the range of 60% to 95% of that before sealing). The heat-sealed exterior material for a power storage device was cut out to a width of 15 mm to prepare a sample. Both opposing ends of the sample were attached to a SUS plate (stainless steel plate) with an adhesive (instant adhesive: a cyanoacrylate adhesive (Cemedine PPX (Cemedine is a registered trademark)) and a 2 kg weight was attached to one side. The other end was hung from above a thermostatic bath and the sample was stored in a thermostatic bath at 150°C to measure creep resistance properties at 150°C, and in an 80°C to measure creep resistance properties at 80°C. Creep resistance was evaluated based on the time it took for the seal to open. The SUS plate used was 2 mm thick, 30 mm wide, 100 mm long, and weighed 42.5 g, with one side in an S-shape. (Evaluation criteria for creep resistance (150℃)) A: The seal does not open for more than 10 minutes. C: The seal opens in less than 10 minutes. (Evaluation criteria for creep resistance (80℃)) A: The seal does not open for more than 10 days. C: The seal opens in less than 10 days.

[0206] <Seal strength measurement in 150℃ environment> In accordance with the provisions of JIS K7127:1999, the seal strength of the exterior material at a measurement temperature of 150°C was measured as follows. A test piece cut into a strip with a width of 15 mm in the TD direction was prepared from the exterior material in the following procedure. Specifically, as shown in Figure 6, first, each exterior material was cut to 60 mm (TD direction) x 200 mm (MD direction) (Figure 6a). Next, the exterior material was folded in half in the MD direction at the fold P (middle in the MD direction) so that the heat-sealable resin layers faced each other (Figure 6b). The heat-sealable resin layers were heat-sealed to each other 10 mm inside the fold P in the MD direction under the conditions of a seal width of 7 mm, a temperature of 240°C, a surface pressure of 1 MPa, and a time of 3 seconds (Figure 6c). In Figure 6c, the shaded area S is the heat-sealed part. Next, the specimen 13 was cut in the MD direction (cut at the position of the two-dot chain line in FIG. 6d) so that the width in the TD direction was 15 mm, and a test piece 13 was obtained (FIG. 6e). Next, the test piece 13 was left in an environment at a temperature of 150°C for 2 minutes, and the heat-sealable resin layer of the heat-sealed portion was peeled off at a speed of 300 mm / min using a tensile tester (manufactured by Shimadzu Corporation, AG-Xplus (product name)) in an environment at a temperature of 150°C (FIG. 7). The maximum strength at the time of peeling was taken as the seal strength (N / 15 mm). The distance between the chucks was 50 mm. The evaluation criteria for the seal strength are as follows, with ratings A and B being acceptable. The measurement was performed three times and the evaluation was based on the average value. The results are shown in Table 1. (Seal strength evaluation criteria) A: The seal strength is 40N / 15mm or more. B: The seal strength is 35N / 15mm or more and less than 40N / 15mm. C: The seal strength is less than 35N / 15mm.

[0207] <Evaluation of the load resistance of electricity storage devices> The load-bearing capacity of the exterior material for a power storage device was evaluated by the following method. The results are shown in Table 1. The exterior material for a power storage device was cut into two pieces so that the width in the TD direction was 300 mm and the length in the MD direction was 300 mm. The heat-sealable resin layers of the two exterior materials for a power storage device were placed opposite each other, and the two opposing sides were heat-sealed at 200 mm (seal width 7 mm) under conditions of 240°C, surface pressure 1 MPa, and 3 seconds, and the remaining side of 300 mm was also heat-sealed (seal width 7 mm), resulting in a three-side sealed state. Next, a stainless steel plate 97 mm long, 70 mm wide, 38 mm thick, and weighing 2100 g was inserted between the heat-sealable resin layers (the length of the stainless steel plate was 97 mm, which was the insertion direction). Two corners of one side of the opened pouch thus obtained (inner dimensions 286 mm × 293 mm) were fastened with clips, and the pouch was hung with the MD direction facing up and down and left to stand for 3 minutes, after which the exterior material for an electricity storage device was observed and rated as A or C based on the following evaluation criterion 1. A stainless steel plate weighing 2100 g was inserted between the layers of the heat-sealable resin of the pouch to check the weight at which the exterior material for an electricity storage device broke, and the pouch was rated as A to C based on the following evaluation criterion 2. (Load-bearing capacity evaluation standard 1) A: There are no pinholes or cracks in the exterior material for the electricity storage device. C: The exterior material for the electricity storage device has a pinhole or a crack. (Load-bearing capacity evaluation standard 2) A: No break at 4200g C: Breaks at less than 4200g

[0208] [Table 1]

[0209] In the laminated structure of the exterior material for power storage devices in Table 1, PET means polyethylene terephthalate, Ny means nylon, PPa means maleic anhydride modified polypropylene, PP means polypropylene, DL means a layer formed by adhesive using the dry lamination method (adhesive layer or adhesive layer), and PBT means polybutylene terephthalate. The numbers in parentheses are the thickness (μm), and " / " indicates the separation between layers.

[0210] As described above, the present disclosure provides the following aspects of the invention. Item 1. The device is composed of a laminate having, from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, An exterior material for an electricity storage device, having a tensile breaking strength, measured by the following method, of 180 MPa or more, and a creep resistance, measured by the following method, of 10 minutes or more. <Measurement of tensile breaking strength> The tensile breaking strength in the MD direction of the exterior material for an electricity storage device is measured using a tensile tester in accordance with the method specified in JIS K7127: 1999. The measurement conditions are a dumbbell No. 7 sample shape, a gauge length of 10 mm, a tensile speed of 0.5 mm / min, and a test environment of 120°C, and the average value is obtained by measuring three times. <Creep resistance measurement> The electrical storage device exterior material is cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half so that the heat-sealing resin layer is on the inside, and heat-sealed at a position 10 mm from the fold with a 7 mm heat seal bar so that the thickness of the heat-sealing resin layer is in the range of 60% to 95% before sealing (i.e., the electrical storage device exterior material is cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half in the MD direction at the midpoint in the MD direction so that the heat-sealing resin layers face each other, and heat-sealed at a position 10 mm back from the fold in the MD direction with a 7 mm heat seal bar so that the thickness of the heat-sealing resin layer is in the range of 60% to 95% before sealing). The heat-sealed electrical storage device exterior material is cut out to a width of 15 mm to obtain a sample. Both opposing ends of the sample are attached to SUS plates (stainless steel plates) with adhesive, and a 2 kg weight is attached to one side. The other end is hung from above the thermostatic chamber and stored in the chamber at 150°C. Creep resistance is evaluated based on the time it takes for the seal to open. The SUS plate used is 2 mm thick, 30 mm wide, 100 mm long, and weighs 42.5 g, with one side in an S-shape. Item 2. The exterior packaging material for an electricity storage device according to Item 1, wherein the heat-sealable resin layer contains polybutylene terephthalate. Item 3. The exterior packaging material for an electricity storage device according to Item 1 or 2, wherein the heat-sealable resin layer contains at least one of homopolybutylene terephthalate and copolymer polybutylene terephthalate. Item 4. The copolymerized polybutylene terephthalate further contains at least one selected from the group consisting of a polyether structure and a polyester structure B in addition to the polybutylene terephthalate structure, Item 4. The exterior material for an electricity storage device according to Item 3, wherein the polyester structure B is a structure different from a polybutylene terephthalate structure. Item 5. The exterior material for an electricity storage device according to Item 4, wherein the polyester structure B has a polycondensation structure of at least one selected from the group consisting of isophthalic acid, dodecanedioic acid, and sebacic acid, and 1,4-butanediol. Item 6. The exterior packaging material for an electricity storage device according to any one of Items 1 to 5, wherein the barrier layer has a thickness of 40 μm or more. Item 7. The packaging material for an electricity storage device according to any one of Items 1 to 6, wherein the heat-sealable resin layer has a thickness of 30 μm or more. Item 8. The exterior packaging material for an electricity storage device according to any one of Items 1 to 5, which has a seal strength of 40 N / 15 mm or more in a 150° C. environment measured by the following measurement method in accordance with the provisions of JIS K7127:1999. <Method of measuring seal strength in a 150℃ environment> A test piece cut into a strip shape with a width of 15 mm in the TD direction is prepared from the exterior material for a power storage device by the following procedure. The exterior material for a power storage device is folded in half in the MD direction at the crease (middle of the MD direction) so that the heat-sealable resin layers face each other. At a position inside the crease 10 mm in the MD direction, the heat-sealable resin layers are heat-sealed to each other under conditions of a seal width of 7 mm, a temperature of 240°C, a surface pressure of 1 MPa, and a time of 3 seconds to form a heat-sealed portion. Next, the test piece is cut in the MD direction so that the width in the TD direction is 15 mm. Next, the test piece is left in an environment at a temperature of 150°C for 2 minutes, and the heat-sealable resin layer of the heat-sealed portion is peeled off at a speed of 300 mm / min in the 150°C environment using a tensile tester. The maximum strength at the time of peeling is the seal strength (N / 15 mm). The distance between the chucks is 50 mm. Item 9. The packaging material for an electricity storage device according to any one of Items 1 to 8, further comprising an adhesive layer between the barrier layer and the heat-sealable resin layer. Item 10. The exterior material for an electricity storage device according to any one of Items 1 to 9, further comprising an adhesive layer between the base layer and the barrier layer. Item 11. The exterior material for an electricity storage device according to any one of Items 1 to 10, which is for an all-solid-state battery, a semi-solid-state battery, a quasi-solid-state battery, a polymer battery, or an all-resin battery. Item 12. The method includes a step of obtaining a laminate in which a base layer, a barrier layer, and a heat-sealable resin layer are laminated in this order from the outside, The laminate has a tensile breaking strength of 180 MPa or more, as measured by the following method, and a creep resistance of 10 minutes or more, as measured by the following method. <Measurement of tensile breaking strength> The tensile breaking strength in the MD direction of the exterior material for electricity storage devices is measured using a tensile tester in accordance with the method specified in JIS K7127: 1999. The measurement conditions are as follows: a dumbbell No. 7 sample shape, a gauge length of 10 mm, a tensile speed of 0.5 mm / min, and a test environment of 120°C. The average value is measured three times. <Creep resistance measurement> The electrical storage device exterior material is cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half so that the heat-sealing resin layer is on the inside, and heat-sealed at a position 10 mm from the fold with a 7 mm heat seal bar so that the thickness of the heat-sealing resin layer is in the range of 60% to 95% before sealing (i.e., the electrical storage device exterior material is cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half in the MD direction at the midpoint in the MD direction so that the heat-sealing resin layers face each other, and heat-sealed at a position 10 mm back from the fold in the MD direction with a 7 mm heat seal bar so that the thickness of the heat-sealing resin layer is in the range of 60% to 95% before sealing). The heat-sealed electrical storage device exterior material is cut out to a width of 15 mm to prepare a sample. Both opposing ends of the sample are attached to SUS plates (stainless steel plates) with adhesive, and a 2 kg weight is attached to one side. The other end is hung from above the thermostatic chamber and stored in the chamber at 150°C. Creep resistance is evaluated based on the time it takes for the seal to open. The SUS plate used is 2 mm thick, 30 mm wide, 100 mm long, and weighs 42.5 g, with one side in an S-shape. Item 13. The method for producing an exterior material for an electricity storage device according to Item 12, wherein the exterior material for an electricity storage device is for an all-solid-state battery, a semi-solid-state battery, a quasi-solid-state battery, a polymer battery, or an all-resin battery. Item 14. An electricity storage device, comprising an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte, housed in a package formed from the exterior material for an electricity storage device according to any one of Items 1 to 11. Item 15. An all-solid-state battery, in which an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed from the exterior material for an electricity storage device according to any one of Items 1 to 11. [Explanation of symbols]

[0211] 1 Base material layer 2 Adhesive layer 3. Barrier layer 4 Heat-fusible resin layer 5 Adhesive layer 6 Surface coating layer 10. Exterior materials for power storage devices 13 Test specimen

Claims

1. The laminate includes at least a base layer, a barrier layer, and a heat-sealable resin layer in this order from the outside, The thickness of the barrier layer is 40 μm or more, An exterior material for an electricity storage device, having a tensile breaking strength, measured by the following method, of 180 MPa or more, and a creep resistance, measured by the following method, of 10 minutes or more. <Measurement of Tensile Breaking Strength> The tensile breaking strength in the MD direction of the exterior material for an electricity storage device is measured using a tensile tester in accordance with the method specified in JIS K7127: 1999. The measurement conditions are a dumbbell No. 7 sample shape, a gauge length of 10 mm, a tensile speed of 0.5 mm / min, and a test environment of 120° C., and the average value is obtained by measuring three times. <Measurement of creep resistance> The electrical storage device exterior material is cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half so that the heat-sealing resin layer is on the inside, and heat-sealed at a position 10 mm from the fold with a 7 mm heat seal bar so that the thickness of the heat-sealing resin layer is in the range of 60% to 95% before sealing. The heat-sealed electrical storage device exterior material is cut out to a width of 15 mm to obtain a sample. Both opposing ends of the sample are attached to SUS plates with adhesive, and a weight of 2 kg is attached to one side. The opposite end is hung from above the thermostatic chamber and stored in the thermostatic chamber at 150 ° C. The creep resistance is evaluated by the time it takes for the seal part to open. The SUS plate used is 2 mm thick, 30 mm wide, 100 mm long, and weighs 42.5 g, with one side in an S-shape.

2. The packaging material for an electricity storage device according to claim 1 , wherein the heat-sealable resin layer contains polybutylene terephthalate.

3. The packaging material for an electricity storage device according to claim 1 or 2, wherein the heat-sealable resin layer contains at least one of homopolybutylene terephthalate and copolymer polybutylene terephthalate.

4. The copolymerized polybutylene terephthalate further contains, in addition to the polybutylene terephthalate structure, at least one selected from the group consisting of a polyether structure and a polyester structure B, The exterior material for an electricity storage device according to claim 3 , wherein the polyester structure B is a structure different from a polybutylene terephthalate structure.

5. The exterior material for a storage battery device according to claim 4, wherein the polyester structure B has a polycondensation structure of at least one selected from the group consisting of isophthalic acid, dodecanedioic acid, and sebacic acid and 1,4-butanediol.

6. The packaging material for an electricity storage device according to claim 1 or 2, wherein the barrier layer has a thickness of 50 µm or more.

7. The packaging material for an electricity storage device according to claim 1 or 2, wherein the thermally adhesive resin layer has a thickness of 30 μm or more.

8. 3. The exterior material for an electricity storage device according to claim 1 or 2, which has a seal strength of 40 N / 15 mm or more in a 150° C. environment measured by the following measurement method in accordance with the provisions of JIS K7127:1999. <Method for measuring seal strength in a 150°C environment> A test specimen cut into a strip having a width of 15 mm in the TD direction is prepared from the exterior material for an electricity storage device by the following procedure. The electrical storage device packaging material is folded in half in the MD direction at the crease (middle of the MD direction) so that the heat-sealable resin layers face each other. The heat-sealable resin layers are heat-sealed to each other at a seal width of 7 mm, a temperature of 240° C., a surface pressure of 1 MPa, and a time of 3 seconds inside the crease in the MD direction to form a heat-sealed portion. Next, the material is cut in the MD direction so that the width in the TD direction is 15 mm to obtain a test piece. Next, the test piece is left in an environment at 150° C. for 2 minutes, and the heat-fusible resin layer of the heat-sealed portion is peeled off at a speed of 300 mm / min using a tensile tester in an environment at 150° C. The maximum strength at the time of peeling is defined as the seal strength (N / 15 mm). The distance between the chucks is 50 mm.

9. The packaging material for an electricity storage device according to claim 1 or 2, further comprising an adhesive layer between the barrier layer and the heat-sealable resin layer.

10. The exterior material for an electricity storage device according to claim 1 or 2, further comprising an adhesive layer between the base layer and the barrier layer.

11. The exterior material for an electricity storage device according to claim 1 or 2, wherein the exterior material for an electricity storage device is for an all-solid-state battery, a semi-solid-state battery, a quasi-solid-state battery, a polymer battery, or an all-resin battery.

12. The method includes a step of obtaining a laminate in which a base layer, a barrier layer, and a thermally adhesive resin layer are laminated in this order from the outside, The thickness of the barrier layer is 40 μm or more, The laminate has a tensile break strength of 180 MPa or more, as measured by the following method, and a creep resistance of 10 minutes or more, as measured by the following method. <Measurement of Tensile Breaking Strength> The tensile breaking strength in the MD direction of the exterior material for an electricity storage device is measured using a tensile tester in accordance with the method specified in JIS K7127: 1999. The measurement conditions are a dumbbell No. 7 sample shape, a gauge length of 10 mm, a tensile speed of 0.5 mm / min, and a test environment of 120°C, and the average value is obtained by measuring three times. <Measurement of creep resistance> The exterior material for an electric storage device is cut out to a width of 60 mm in the TD direction and a length of 150 mm in the MD direction, folded in half so that the heat-sealing resin layer is on the inside, and heat-sealed so that the thickness of the heat-sealing resin layer is in the range of 60% to 95% of the thickness before sealing. The heat-sealed exterior material for an electric storage device is cut out to a width of 15 mm to obtain a sample. Both opposing ends of the sample are attached to SUS plates with an adhesive, and a 2 kg weight is attached to one side. The opposite end is hung from above a thermostatic chamber and stored in the thermostatic chamber at 150°C. The SUS plate used is 2 mm thick, 30 mm wide, 100 mm long, weighs 42.5 g, and has an S-shaped side. Creep resistance is evaluated based on the time it takes for the seal to open.

13. The method for producing an exterior material for an electricity storage device according to claim 12, wherein the exterior material for an electricity storage device is for an all-solid-state battery, a semi-solid-state battery, a quasi-solid-state battery, a polymer battery, or an all-resin battery.

14. 3. An electricity storage device, comprising: an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte, housed in a package formed from the exterior material for an electricity storage device according to claim 1 or 2.

15. 3. An all-solid-state battery, comprising an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte, housed in a packaging body formed from the exterior material for an electricity storage device according to claim 1 or 2.

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