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

Abstract

An exterior material for a power storage device, composed of a laminate comprising at least a substrate layer, a barrier layer, and a hot-melt resin layer in this order, wherein the hot-melt resin layer has a logarithmic decrement ΔE at 150°C of 0.075 or less in a rigid-body pendulum measurement.

Description

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

[0001] The present disclosure relates to an exterior material for an electricity storage device, a method for producing the same, and an electricity storage device.

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

[0003] Meanwhile, in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., there has been a demand for electricity storage devices to have a variety of shapes as well as to be thinner and lighter in weight. 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 on how much they can be made lighter.

[0004] Therefore, 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 electrical storage device packaging material, a recess is generally formed by cold forming, and electrical storage device elements such as electrodes and electrolyte are placed in the space formed by the recess, and a heat-sealable resin layer is heat-sealed to obtain an electrical storage device in which the electrical storage device elements are housed inside the electrical storage device packaging material.

[0006] Japanese Patent Application Laid-Open No. 2008-287971

[0007] An electricity storage device may be required to have heat resistance in an extremely high-temperature environment, for example, 150°C. For example, an electricity storage device used in the engine compartment of an automobile is required to have heat resistance that allows it to be used in an environment of 150°C. Furthermore, for example, some all-solid-state batteries become hot during use, and even when the electricity storage device is an all-solid-state battery, heat resistance in a high-temperature environment is required. Similar heat resistance is also required for an exterior material for an electricity storage device used in an electricity storage device that is required to have heat resistance in a high-temperature environment. Specifically, such an exterior material for an electricity storage device is required to have high sealing strength in an extremely high-temperature environment, such as 150°C.

[0008] Under these circumstances, a first aspect of the present disclosure has a primary object to provide an exterior packaging material for an electricity storage device that has excellent heat resistance.

[0009] Furthermore, conventionally, high water vapor barrier properties have been required for packaging materials for electricity storage devices. At the heat-sealed portion of the packaging material for electricity storage devices, where the heat-sealed resin of the packaging material for electricity storage devices is heat-sealed to house the electricity storage device elements, the heat-sealed resin that forms the heat-sealed resin layer is also required to have high water vapor barrier properties in order to prevent water vapor from penetrating from the end face. Furthermore, in sulfide-based all-solid-state batteries that do not use a liquid electrolyte, hydrogen sulfide is generated by moisture in the air. For this reason, higher water vapor barrier properties are required for packaging materials for electricity storage devices such as sulfide-based all-solid-state batteries. Thus, high water vapor barrier properties are required for packaging materials for electricity storage devices.

[0010] A second aspect of the present disclosure has a main object to provide an exterior packaging material for an electricity storage device that has excellent water vapor barrier properties.

[0011] Furthermore, electricity storage devices are sometimes required to have heat resistance in extremely high-temperature environments, for example, at 150°C. For example, electricity storage devices used in the engine compartment of an automobile are required to have heat resistance that allows them to be used in an environment of 150°C. Furthermore, for example, some all-solid-state batteries become hot during use, and even when the electricity storage device is an all-solid-state battery, heat resistance in a high-temperature environment is required. Similar heat resistance is also required for packaging materials for electricity storage devices used in electricity storage devices that require heat resistance in a high-temperature environment. Specifically, such packaging materials for electricity storage devices are required to have high sealing strength in an extremely high-temperature environment of 150°C.

[0012] Furthermore, packaging materials for electricity storage devices are also required to have excellent insulating properties in high-temperature environments.

[0013] Under these circumstances, a third aspect of the present disclosure has a main object to provide an exterior packaging material for an electricity storage device that has excellent heat resistance and insulating properties in high-temperature environments.

[0014] (First Aspect) The inventors of the present disclosure conducted extensive research to solve the problems of the first aspect as described above. As a result, they found that in a packaging material for an electricity storage device constituted by a laminate including at least a barrier layer and a heat-sealable resin layer in this order, by using a heat-sealable resin layer having a logarithmic decrement ΔE at 150°C in a rigid pendulum measurement of a predetermined value or less, it is possible to obtain a packaging material for an electricity storage device having high sealing strength in an environment as extremely high as 150°C.

[0015] The first aspect of the present disclosure has been completed through further investigation based on these findings. That is, the first aspect of the present disclosure provides the following invention: An exterior packaging material for an electricity storage device, which is composed of a laminate including at least a barrier layer and a heat-sealable resin layer in this order, wherein the heat-sealable resin layer has a logarithmic decrement ΔE of 0.075 or less at 150°C in a rigid pendulum measurement.

[0016] (Second Aspect) Furthermore, the inventors of the present disclosure conducted extensive research to solve the problem of the second aspect as described above, and as a result, found that in a packaging material for an electricity storage device constituted by a laminate including at least a barrier layer and a thermally adhesive resin layer in this order, the water vapor barrier property of the packaging material for an electricity storage device can be improved by controlling the size and crystal structure of the islands in the sea-island structure observed in a cross-sectional image of the thermally adhesive resin layer.

[0017] A second aspect of the present disclosure has been completed based on these findings and through further investigation. That is, the second aspect of the present disclosure provides the following invention: an exterior packaging material for an electricity storage device, which is composed of a laminate including at least a barrier layer and a thermally adhesive resin layer in this order, wherein a sea-island structure is observed in a cross-sectional image of a cross section of the thermally adhesive resin layer in a direction parallel to the TD and in the thickness direction, obtained using a field emission scanning electron microscope, wherein when the cross-sectional image is observed at a magnification of 20,000 times over an area of ​​4.50 μm × 6.37 μm, the number of island portions having a maximum diameter of 100 nm or more and less than 300 nm is 10 or less and the number of island portions having a maximum diameter of 300 nm or more is 10 or less, and the island portion does not include any island portion having a maximum diameter of 300 nm or more, and when the cross-sectional image is observed at a magnification of 50,000 times over, lamellae crystals are observed in the island portions.

[0018] (Third Aspect) Furthermore, the inventors of the present disclosure conducted extensive research to solve the problem of the third aspect as described above. As a result, they found that in a packaging material for an electricity storage device constituted by a laminate including at least a barrier layer and a heat-sealable resin layer in this order, a DSC curve obtained by differential scanning calorimetry for the heat-sealable resin layer satisfies predetermined conditions, thereby obtaining a packaging material for an electricity storage device that is excellent in heat resistance and insulation properties in high-temperature environments.

[0019] The third aspect of the present disclosure has been completed based on these findings and through further investigation. That is, the third aspect of the present disclosure provides the following invention: An exterior packaging material for an electricity storage device, which is composed of a laminate including at least a barrier layer and a heat-sealable resin layer in this order, wherein the heat-sealable resin layer has a melting peak temperature of 160.0°C or higher, no shoulder peak in the temperature range of 100.0°C to 150.0°C, and a shoulder peak at a temperature above 150.0°C, in a DSC curve obtained by differential scanning calorimetry.

[0020] According to a first aspect of the present disclosure, it is possible to provide a packaging material for an electricity storage device having excellent heat resistance. Furthermore, according to the first aspect of the present disclosure, it is also possible to provide a method for manufacturing the packaging material for an electricity storage device, and an electricity storage device using the packaging material for an electricity storage device.

[0021] According to a second aspect of the present disclosure, it is possible to provide a packaging material for an electricity storage device having excellent water vapor barrier properties. Furthermore, according to the second aspect of the present disclosure, it is also possible to provide a method for manufacturing the packaging material for an electricity storage device, and an electricity storage device using the packaging material for an electricity storage device.

[0022] According to a third aspect of the present disclosure, it is possible to provide a packaging material for an electricity storage device that has excellent heat resistance and insulating properties in a high-temperature environment. Furthermore, according to the third aspect of the present disclosure, it is also possible to provide a method for manufacturing the packaging material for an electricity storage device, and an electricity storage device that uses the packaging material for an electricity storage device.

[0023] FIG. 1 is a schematic diagram showing an example of the cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. FIG. 2 is a schematic diagram showing an example of the cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. FIG. 3 is a schematic diagram showing an example of the cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. FIG. 4 is a schematic diagram for explaining a method of housing an electricity storage device element in a package formed from an exterior material for an electricity storage device according to the present disclosure. FIG. 5 is a schematic diagram for explaining a method of rigid pendulum measurement. FIG. 6 is a schematic diagram for explaining a method of measuring seal strength. FIG. 7 is a schematic diagram for explaining a method of measuring seal strength. FIG. 8 is an image (cross-sectional image obtained using a field emission scanning electron microscope) of an island portion having a layer having a thickness of 10 nm or more (portion sandwiched between arrows) at the boundary between the island portion and the sea portion. FIG. 9 is a schematic diagram for explaining a method of evaluating electrolyte resistance. FIG. 10 is a schematic diagram for explaining a method of evaluating the water vapor barrier property of a package formed from an exterior material for an electricity storage device. 9 is a DSC curve obtained by differential scanning calorimetry for the heat-sealable resin layer of the electrical storage device casing material obtained in Example 1C. It is a DSC curve obtained by differential scanning calorimetry for the heat-sealable resin layer of the electrical storage device casing material obtained in Comparative Example 1C. It is a DSC curve obtained by differential scanning calorimetry for the heat-sealable resin layer of the electrical storage device casing material obtained in Comparative Example 2C. It is an enlarged image of FIG.

[0024] The packaging material for an electricity storage device according to the first aspect of the present disclosure is composed of a laminate including at least a barrier layer and a heat-sealable resin layer in this order, and is characterized in that the heat-sealable resin layer has a logarithmic decrement ΔE of 0.075 or less at 150°C in a rigid pendulum measurement. The packaging material for an electricity storage device according to the first aspect of the present disclosure is provided with this configuration, thereby enabling it to exhibit excellent heat resistance.

[0025] The electrical storage device packaging material according to a second aspect of the present disclosure is composed of a laminate including at least a barrier layer and a thermally adhesive resin layer in this order, wherein a sea-island structure is observed in a cross-sectional image of the thermally adhesive resin layer taken in a direction parallel to the TD and thickness direction using a field emission scanning electron microscope, wherein when the cross-sectional image is observed at a magnification of 20,000 times over an area of ​​4.50 μm × 6.37 μm, the number of island portions having a maximum diameter of 100 nm or more and less than 300 nm is 10 or less and the number of island portions having a maximum diameter of 300 nm or more is 0 or less, and the island portion does not include any island portion having a maximum diameter of 300 nm or more, and when the cross-sectional image is observed at a magnification of 50,000 times over, lamellar crystals are observed in the island portions. The electrical storage device packaging material according to the second aspect of the present disclosure has this configuration, thereby enabling it to exhibit excellent water vapor barrier properties.

[0026] The electrical storage device packaging material of the third aspect of the present disclosure is composed of a laminate including at least a barrier layer and a heat-sealable resin layer in this order, and is characterized in that, in a DSC curve obtained by differential scanning calorimetry, the heat-sealable resin layer has a melting peak temperature of 160.0° C. or higher, no shoulder peak in the temperature range of 100.0° C. or higher and 150.0° C. or lower, and a shoulder peak at a temperature above 150.0° C. The electrical storage device packaging material of the third aspect of the present disclosure has this configuration, and thereby can exhibit excellent heat resistance and insulating properties in high-temperature environments.

[0027] Hereinafter, the packaging material for an electricity storage device according to the present disclosure will be described in detail. In the description of this specification, content common to each aspect of the present disclosure (i.e., the first aspect, the second aspect, and the third aspect) will be described as content relating to the present disclosure, and content relating to each aspect will be described by indicating which aspect the content relates to.

[0028] In the present disclosure, a numerical range indicated by "to" means "greater than or equal to" or "less than or equal to." For example, the notation 2 to 15 mm means 2 mm or greater and 15 mm or less. In the numerical ranges described in stages in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, separately described upper and lower limits, upper and lower limits, or lower and lower limits may each be combined to form a numerical range. Furthermore, in the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

[0029] In the packaging material for an electricity storage device, the MD (machine direction) and TD (transverse direction) of the barrier layer 3 described below can usually be determined during 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 determined by observing the surface of the metal foil. Furthermore, during the manufacturing process of a laminate, the MD of the laminate usually coincides with the RD of the metal foil. Therefore, the MD of the laminate can be determined by observing the surface of the metal foil of the laminate and identifying the rolling direction (RD) of the metal foil. Furthermore, since the TD of the laminate is perpendicular to the MD of the laminate, the TD of the laminate can also be identified. Similarly, since the MD of the heat-fusible resin layer coincides with the RD of the metal foil, the MD of the heat-fusible resin layer can be identified by observing the surface of the metal foil of the laminate and identifying the rolling direction (RD) of the metal foil. Furthermore, since the TD of the heat-fusible resin layer is perpendicular to the MD of the heat-fusible resin layer, the TD of the heat-fusible resin layer can also be identified.

[0030] Furthermore, when the MD of an electrical storage device packaging material cannot be determined due to rolling marks on a metal foil such as an aluminum alloy foil or a stainless steel foil, it can be determined by the following method. One method for determining the MD of an electrical storage device packaging material is to observe the cross section of the heat-sealable resin layer of the electrical storage device packaging material using 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 island shapes in the direction perpendicular to the thickness direction of the heat-sealable resin layer is largest can be determined as the MD. Specifically, the sea-island structure is confirmed by observing, using an electron microscope, a cross section in the longitudinal direction of the heat-sealable resin layer and each cross section in a direction angled 10 degrees from the direction parallel to the longitudinal cross section (a total of 10 cross sections). Next, the shape of each individual island is observed in each cross section. For each island shape, the linear distance connecting the leftmost end in the direction perpendicular to the thickness direction of the heat-sealable resin layer to the rightmost end in the perpendicular direction is defined as the diameter y. For each cross section, the average of the 20 largest diameters y of the island shapes is calculated. The direction parallel to the cross section with the largest average diameter y of the island shapes is determined to be the MD.

[0031] 1. Laminated Structure and Physical Properties of the Electricity Storage Device Exterior Material The electricity storage device exterior material 10 of the present disclosure is composed of a laminate including a barrier layer 3 and a heat-sealable resin layer 4 in this order, as shown in FIG. 1 . In the electricity storage device exterior material 10, the barrier layer 3 side (or the base material layer 1 side if a base material layer 1 is included) is the outermost layer, and the heat-sealable resin layer 4 is the innermost layer. When assembling an electricity storage device using the electricity storage device exterior material 10 and an electricity storage device element, the heat-sealable resin layers 4 of the electricity storage device exterior material 10 are placed opposite each other, and the electricity storage device element is housed in a space formed by heat-sealing the peripheral portions. In the laminate constituting the electricity storage device exterior material 10 of the present disclosure, the barrier layer 3 is used as the reference, and the heat-sealable resin layer 4 side is located inside the barrier layer 3.

[0032] As shown in Figures 2 to 4, for example, the packaging 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. Furthermore, as shown in Figures 3 and 4, for example, the packaging material 10 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. Furthermore, as shown in Figure 4, a surface coating layer 6 or the like may be provided on the barrier layer 3 side (if the base material layer 1 is included, on the outer side of the base material layer 1 (the side opposite to the heat-sealable resin layer 4 side)), if necessary.

[0033] The thickness of the laminate constituting the electrical storage device exterior material 10 is not particularly limited, but from the viewpoint of cost reduction, improvement of energy density, etc., examples of the thickness include about 300 μm or less, preferably about 250 μm or less, about 210 μm or less, about 190 μm or less, about 180 μm or less, about 155 μm or less, and about 120 μm or less. Furthermore, from the viewpoint of maintaining the function of the electrical storage device exterior material to protect the electrical storage device elements, the thickness of the laminate constituting the electrical storage device exterior material 10 is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more, about 155 μm or more, and about 190 μm or more. Furthermore, preferred ranges for the laminate constituting the exterior packaging material 10 for an electricity storage device are, for example, about 35 to 300 μm, about 35 to 250 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 300 μm, about 45 to 250 μm, about 45 to 210 μm, about 45 to 190 μm, about 45 to 180 μm, about 45 to 155 μm, about 45 to 120 μm, about 60 to 300 μm, about 60 to 250 μm, and about 60 to 300 μm. Examples of the thickness include about 210 μm, about 60 to 190 μm, about 60 to 180 μm, about 60 to 155 μm, about 60 to 120 μm, about 155 to 300 μm, about 155 to 250 μm, about 155 to 210 μm, about 155 to 190 μm, about 155 to 180 μm, about 190 to 300 μm, about 190 to 250 μm, and about 190 to 210 μm. In particular, when making the power storage device lightweight and thin, about 60 to 155 μm is preferred, and when improving formability, about 155 to 190 μm is preferred.

[0034] In the electrical storage device packaging material 10, the ratio of the total thickness of the base material layer 1 (optional), adhesive layer 2 (optional), barrier layer 3, adhesive layer 5 (optional), heat-sealable resin layer 4, and surface coating layer 6 (optional) to the thickness (total thickness) of the laminate constituting the electrical storage device packaging material 10 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the electrical storage device packaging material 10 of the present disclosure includes the base material layer 1, adhesive layer 2, barrier layer 3, adhesive layer 5, and heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the electrical storage device packaging material 10 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Furthermore, even when the electrical storage device packaging material 10 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 electrical storage device packaging material 10 can be, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0035] The sealing strength of the electrical storage device packaging material of the present disclosure in a 150°C environment, measured by the method described below in <Measurement of Seal Strength at 25°C or 150°C>, is preferably about 15.0 N / 15mm or more, more preferably about 20.0 N / 15mm or more, and even more preferably about 25.0 N / 15mm or more. The upper limit is, for example, about 150.0 N / 15mm or less, about 100.0 N / 15mm or less, and preferred ranges include about 15.0 to 150.0 N / 15m, about 15.0 to 100.0 N / 15m, about 20.0 to 150.0 N / 15m, about 20.0 to 100.0 N / 15m, about 25.0 to 150.0 N / 15m, and about 25.0 to 100.0 N / 15m.

[0036] Furthermore, the packaging material for an electricity storage device according to the present disclosure has a seal strength in an environment of 25°C, measured by the method described below in <Measurement of seal strength at 25°C or 150°C>, of preferably about 100.0 N / 15 mm or more, more preferably about 120.0 N / 15 mm or more, and even more preferably about 140.0 N / 15 mm or more. There is no particular upper limit, and the stronger the seal strength, the better. For example, it is about 300.0 N / 15 mm or less, about 250.0 N / 15 mm or less, and preferred ranges include about 100.0 to 300.0 N / 15 m, about 100.0 to 250.0 N / 15 m, about 120.0 to 300.0 N / 15 m, about 120.0 to 250.0 N / 15 m, about 140.0 to 300.0 N / 15 m, and about 140.0 to 250.0 N / 15 m.

[0037] <Measurement of Seal Strength at 25°C or 150°C> In accordance with the provisions of JIS K7127:1999, the seal strength of the electrical storage device packaging material at each measurement temperature of a 25°C environment and a 150°C environment was measured as follows. As test pieces, the electrical storage device packaging material was cut into strips with a width of 15 mm in the TD direction. Specifically, as shown in FIG. 7, each electrical storage device packaging material was first cut into 75 mm (TD direction) x 150 mm (MD direction) (FIG. 7a). Next, the electrical storage device packaging material was folded in half in the MD direction at the fold line P (middle in the MD direction) so that the heat-sealable resin layers faced each other (FIG. 7b). The heat-sealable resin layers were heat-sealed approximately 10 mm inward from the fold line P under conditions of a seal width of 7 mm, a temperature of 190°C, a surface pressure of 1.0 MPa, and a time of 3 seconds (FIG. 7c). In Figure 7c, the shaded area S indicates the heat-sealed portion. Next, the test piece 13 was cut in the MD direction (cut at the position of the two-dot chain line in Figure 7d) so that the width in the TD direction was 15 mm to obtain a test piece (Figure 7e). Next, the test piece 13 was left at each measurement temperature for 5 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 under each measurement temperature environment (Figure 8). 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. Note that in measuring the seal strength, the test piece 13 may peel off (break) at the heat-sealed interface A shown in Figure 8, or it may break at a location other than the heat-sealed interface A (for example, at position B in Figure 8). If the test piece 13 breaks at position B in Figure 8, the value measured at that time was taken as the seal strength.

[0038] Furthermore, the packaging material for an electricity storage device according to the present disclosure preferably does not exhibit whitening in terms of formability evaluated by the method described in <Evaluation of formability> described below.

[0039] <Moldability Evaluation> Each electrical storage device exterior material was cut into a length (MD) x width (TD) of 55 mm to prepare a test sample. This test sample was molded using a rectangular molding die (female die) with a bore of 30.0 mm (MD) x 30.0 mm (TD) in an environment of 25°C. Cold molding (single-stage pull-in molding) was performed with a pressing pressure (surface pressure) of 0.18 MPa and a stroke speed of 20 mm / s to obtain a molding depth of 12.0 mm. The test sample was placed on the female die so that the heat-sealable resin layer was positioned on the male die side and molded. The heat-sealable resin layer of the molded test sample was visually observed to confirm the presence or absence of whitening. Whitening occurred mainly around the corners of the molded part.

[0040] Furthermore, the packaging material for an electricity storage device according to the first aspect of the present disclosure has an impregnation seal strength (seal strength in a state where a sample is impregnated with an electrolyte solution), measured by the method described in <Evaluation of Electrolyte Resistance> described below, of preferably about 20.0 N / 15 mm or more, more preferably about 80.0 N / 15 mm or more, and even more preferably about 130.0 N / 15 mm or more. There is no particular upper limit, and the stronger the seal strength, the better. For example, it is about 300.0 N / 15 mm or less, about 250.0 N / 15 mm or less, and preferred ranges include about 20.0 to 300.0 N / 15 mm, about 20.0 to 250.0 N / 15 mm, about 80.0 to 300.0 N / 15 mm, about 80.0 to 250.0 N / 15 mm, about 130.0 to 300.0 N / 15 mm, and about 130.0 to 250.0 N / 15 mm.

[0041] <Evaluation of Electrolyte Resistance> A sample was prepared from an electrical storage device packaging material cut to a size of 90 mm in TD × 200 mm in MD, as shown in the schematic diagram of Fig. 10. The sample was folded at a location 100 mm in MD, and in the folded state, both ends in the TD direction were heat-sealed under conditions of a width of 7 mm, a surface pressure of 1.0 MPa, a sealing temperature of 190°C, and a sealing time of 3.0 seconds, to form a bag-shaped package having an opening formed from the electrical storage device packaging material. Next, the bag-shaped package is stored for one day in a dry room with a dew point of -40 ° C., and an electrolyte solution (obtained by mixing lithium hexafluorophosphate to a solution mixed in a volume ratio of ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1:1:1 to make 1 mol / L) is poured into the remaining open edge (opening), and the opening is heat-sealed under conditions of a width of 7 mm, a surface pressure of 1.0 MPa, a sealing temperature of 190 ° C., and a sealing time of 3.0 seconds to seal the electrolyte inside the package. The package is stored for 14 days in an 85 ° C. environment with the heat-sealed edge of the opened object facing up. After storage, the heat-sealed edge of the opened object is cut off to open it, the electrolyte solution is removed, and within 3 hours, the heat-sealable resin layers at the points where the electrolyte had been in contact are heat-sealed to each other perpendicular to the MD direction under conditions of a width of 7 mm, a surface pressure of 1.0 MPa, a sealing temperature of 190 ° C., and a sealing time of 3.0 seconds. A 15 mm wide sample was cut perpendicular to the TD direction to prepare a sample for measuring the seal strength when pulled in the MD direction. Within 1 hour of heat sealing, the impregnation seal strength (seal strength of the sample impregnated with the electrolyte) after 14 days in an 85°C environment was measured using the same equipment and conditions as for the seal strength in the 25°C environment described above.

[0042] Furthermore, the packaging material for an electricity storage device according to the second aspect of the present disclosure preferably has a water vapor permeability coefficient at a temperature of 65°C and a relative humidity of 90%, measured by the method described in <Evaluation of the water vapor barrier property of a package formed from a packaging material for an electricity storage device> described below, of about 5.0 g mm / m 2 ·day or less, more preferably about 4.8 g·mm / m 2 ·day or less, more preferably about 4.6 g·mm / m 2 The lower limit is, for example, about 0.0 g mm / m 2 ・More than 1.2g・mm / m2 The preferred range is 0.0 to 5.0 g mm / m 2 ・Day degree, 0.0-4.8g・mm / m 2 ・Day degree, 0.0-4.6g・mm / m 2 ・Day degree, 1.2-5.0g・mm / m 2 ・Day degree, 1.2-4.8g・mm / m 2 ・Day degree, 1.2-4.6g・mm / m 2 ・Days are an example.

[0043] <Evaluation of Water Vapor Barrier Properties of Packaging Formed from Sheathing Material for Electricity Storage Devices> As shown in the schematic diagram of FIG. 11 , a packaging material for an electricity storage device cut to 75 mm in TD x 150 mm in MD was used as a sample. The sample was folded at 75 mm in MD, and in the folded state, both ends in the TD direction were heat-sealed under conditions of a width of 7 mm, a surface pressure of 1.0 MPa, a sealing temperature of 190°C, and a sealing time of 3.0 seconds to form a bag-shaped package formed from the sheathing material for an electricity storage device with an opening. The sealed portions at both ends in the TD direction were designated as the left and right sealed portions. At this time, the thicknesses of the left and right sealed portions were measured with a thickness meter, and the thicknesses of the substrate layer, barrier layer, and adhesive layer were subtracted from the respective left and right thicknesses (only the thickness of the layer closer to the heat-sealable resin layer than the barrier layer) to determine the thickness of the sealed portion. Next, the left and right sealed portions at both ends were cut to 3 mm. The 3.0 mm sealed portion after cutting was the water vapor permeation distance. Next, the bag-shaped package was stored for one day in a dry room with a dew point of -40°C, and 2.0 g of solution (a solution containing ethylene carbonate, diethyl carbonate, and dimethyl carbonate mixed in a volume ratio of 1:1:1) was poured into the remaining open edge (opening). The opening was heat-sealed to a width of 7 mm, with a surface pressure of 1.0 MPa, a sealing temperature of 190°C, and a sealing time of 3.0 seconds to seal the solution inside the package. The sealed portion into which the solution was poured is defined as the top. The film thickness of the top sealed portion was measured with a film thickness meter, and the value obtained by subtracting the thicknesses of the base layer, barrier layer, and adhesive layer (only the thickness of the layer closer to the heat-sealable resin layer than the barrier layer) was defined as the seal film thickness. The top sealed portion created by sealing the opening was cut to 3.0 mm. The 3.0 mm seal after cutting was the water vapor permeation distance. The length of each sealed portion of the package (left and right sides and the top portion where the solution was sealed) containing the solution was measured with a metal ruler. As shown in the bottom diagram of Figure 11, the two corners of the resulting package (the areas that were sealed twice) account for only a small proportion of the entire sealed area, so it can be said that they have almost no effect on the evaluation of the water vapor barrier property. 2 is set according to the following formula: Water vapor permeation cross section = cross section at both ends (right seal film thickness × right length + left seal film thickness × left length) + upper cross section (upper seal film thickness × upper seal length)

[0044] The moisture content (ppm) of the solution at the time of encapsulation is measured using coulometric titration by the Karl Fischer method. Next, the solution is left for 4 weeks in a thermo-hygrostat chamber at a temperature of 65°C and a relative humidity of 90%, and the moisture content per 2.0 g of the solution after 4 weeks is measured. The moisture content after 4 weeks of encapsulation (before encapsulation) is also measured using coulometric titration by the Karl Fischer method, as in the case of encapsulation (before encapsulation). The moisture content (ppm) measured after 4 weeks of encapsulation at a temperature of 65°C and a relative humidity of 90%, the moisture content (ppm) at the time of encapsulation (before encapsulation in the thermo-hygrostat chamber at a temperature of 65°C and a relative humidity of 90%), the amount of encapsulated solution (g), and the water vapor permeation cross-sectional area (m 2 ), and the time (days) at a temperature of 65°C and a relative humidity of 90% were used to calculate the water vapor permeability coefficient (g mm / m 2 ・day) is calculated. At this time, the value is rounded to one decimal place to calculate the value to one decimal place. Water vapor transmission coefficient = (water vapor transmission distance × (water content measured after leaving at a temperature of 65°C and a relative humidity of 90% for 4 weeks - water content at the time of encapsulation) × amount of encapsulated solution) / (water vapor transmission cross-sectional area × insertion time at a temperature of 65°C and a relative humidity of 90%)

[0045] The packaging material for an electricity storage device according to the second aspect of the present disclosure preferably has a water vapor permeability coefficient of about 0.68 g mm / m at a temperature of 40°C and a relative humidity of 90%, as measured by the method described in the above-mentioned <Evaluation of the water vapor barrier property of a package formed from a packaging material for an electricity storage device>. 2 ·day or less, more preferably about 0.66 g·mm / m 2 ·day or less, more preferably about 0.64 g·mm / m 2 The lower limit is, for example, about 0.00 g mm / m 2 ・More than 0.10g・mm / m 2 ・More than 0.20g・mm / m 2 The preferred range is 0.00 to 0.68 g mm / m 2 ・Day degree, 0.00-0.66g・mm / m 2 ・Day degree, 0.00-0.64g・mm / m 2 ・Day degree, 0.10-0.68g・mm / m 2・Day degree, 0.10-0.66g・mm / m 2 ・Day degree, 0.10-0.64g・mm / m 2 ・Day degree, 0.20-0.68g・mm / m 2 ・Day degree, 0.20-0.66g・mm / m 2 ・Day degree, 0.20-0.64g・mm / m 2 ・Examples include about a day.

[0046] For the evaluation of the water vapor barrier property at a temperature of 40°C and a relative humidity of 90%, the water vapor permeability coefficient (g mm / m) was measured in the same manner as in the evaluation of the water vapor barrier property at a temperature of 65°C and a relative humidity of 90% described above, except that the temperature and humidity chamber at a temperature of 65°C and a relative humidity of 90% was changed to a temperature and humidity chamber at a temperature of 40°C and a relative humidity of 90%. 2 At this time, the value to the second decimal place is calculated by rounding off the third decimal place.

[0047] Furthermore, the packaging material for an electricity storage device according to the third aspect of the present disclosure preferably has a volume resistivity in a 150°C environment of about 1.0 x 10, as measured by the method described in <Insulating property evaluation (volume resistivity) in a 150°C environment> described below. 14 Ω cm or more, more preferably about 1.5×10 14 Ω cm or more, more preferably about 2.0 × 10 14 Ω cm or more, and the upper limit is, for example, about 1.0 × 10 18 Ω cm or less, and the preferred range is 1.0 × 10 14 Ω・cm~1.0×10 18 Approximately Ω・cm, 1.5×10 14 Ω・cm~1.0×10 18 About Ω・cm, 2.0~×10 14 ~1.0 x 10 18 The example is about Ω·cm.

[0048] <Insulation evaluation (volume resistivity) in a 150°C environment> The exterior material for an electricity storage device is cut to a 10 cm x 10 cm piece, and the film thickness is measured. A digital ultra-high resistance / microcurrent meter is used to measure the volume resistivity of the exterior material for an electricity storage device in accordance with the provisions of IEC 62631-3-1. The sample is placed in a resistivity chamber set to 150°C, and after 3 minutes the temperature has stabilized at 150°C, 500 V is applied, and the volume resistivity is calculated from the current value and film thickness after 1 minute.

[0049] 2. Layers Constituting the Electric Storage Device Sheathing Material [Substrate Layer 1] In the present disclosure, the substrate layer 1 is a layer that is provided as necessary for the purpose of exhibiting the function as a substrate of the electricity storage device sheathing material, etc. The substrate layer 1 is located on the outer layer side of the electricity storage device sheathing material.

[0050] There are no particular limitations on the material forming the substrate layer 1, as long as it functions as a substrate, i.e., has at least insulating properties. The substrate layer 1 can be formed using, for example, a resin, which may contain an additive described below.

[0051] 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 pre-formed 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 produce the electrical storage device packaging material 10 of the present disclosure. Alternatively, 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 stretched films include uniaxially stretched films and biaxially stretched films, with biaxially stretched films being preferred. Examples of stretching methods for forming a biaxially stretched film include sequential biaxial stretching, inflation, and simultaneous biaxial stretching. Examples of methods for applying the resin include roll coating, gravure coating, and extrusion coating.

[0052] Examples of resins that form the base layer 1 include polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenolic resin, as well as modified versions of these resins. The resin that forms the base layer 1 may also be a copolymer of these resins, a modified version of the copolymer, or a mixture of these resins.

[0053] The base layer 1 preferably contains these resins as the main component, and more preferably contains polyester or polyamide as the main component. Here, "main component" means that the content of the resin component 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.

[0054] Of these, polyester and polyamide are preferred as the resin for forming the base layer 1.

[0055] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters. Examples of copolymer polyesters include copolymer polyesters in which ethylene terephthalate is the main repeating unit. Specific examples include copolymer 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 / decanedicarboxylate). These polyesters may be used alone or in combination of two or more.

[0056] 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 (where I represents isophthalic acid and T represents terephthalic acid) containing structural units derived from terephthalic acid and / or isophthalic acid; and aromatic polyamides 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, which 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.

[0057] The base layer 1 preferably includes at least one of a polyester film, a polyamide film, and a polyolefin film, and preferably includes at least one of a stretched polyester film, a stretched polyamide film, and a stretched polyolefin film, and 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.

[0058] The base material layer 1 may be a single layer or may be composed of two or more layers. When the base material layer 1 is composed of two or more layers, the base material layer 1 may be a laminate in which resin films are laminated with an adhesive or the like, or a laminate of resin films formed by co-extrusion of resins into two or more layers. Furthermore, a laminate of resin films formed by co-extrusion of resins into two or more layers may be used as the base material layer 1 without being stretched, or may be uniaxially or biaxially stretched to form the base material layer 1.

[0059] Specific examples of the laminate of two or more resin films in the base layer 1 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. A laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more stretched nylon films, or a laminate of two or more stretched polyester films is preferred. 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. 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. Furthermore, since polyester resins are less likely to discolor when an electrolytic solution adheres to their surface, it is preferred that the polyester resin film be located as the outermost layer of the base layer 1 when the base layer 1 is a laminate of two or more resin films. In the laminate of polyester resin film and polyamide resin film, preferred ranges of the thickness of the polyester resin film are 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 10 to 11 μm, about 18 to 33 μm, and 18 to 28 μm. and about 18 to 23 μm. Preferred ranges of the thickness of the polyamide resin film 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 10 to 11 μm, about 18 to 33 μm, about 18 to 28 μm, and about 18 to 23 μm.

[0060] When the base layer 1 is a laminate of two or more resin film layers, the two or more resin film layers may be laminated via an adhesive. Examples of preferred adhesives include those similar to those exemplified for adhesive layer 2 described below. The method for laminating two or more resin film layers is not particularly limited, and known methods can be used, such as dry lamination, sandwich lamination, extrusion lamination, and thermal lamination, with dry lamination being preferred. When laminating using the dry lamination method, it is preferable to use a polyurethane adhesive as the adhesive. In this case, the thickness of the adhesive may be, for example, about 2 to 5 μm. Alternatively, an anchor coat layer may be formed on the resin film before lamination. Examples of the anchor coat layer include those similar to those exemplified for adhesive layer 2 described below. In this case, the thickness of the anchor coat layer may be, for example, about 0.01 to 1.0 μm.

[0061] Furthermore, additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, antistatic agents, and colorants 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.

[0062] In the present disclosure, from the viewpoint of improving the formability of the exterior material for an electrical storage device, it is preferable that a lubricant be present on at least one of the surface and the interior of the base material layer 1. The lubricant is not particularly limited, but preferably an amide-based lubricant is used. Specific examples of amide-based lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, 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 amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. Specific examples of methylolamides include methylol stearic acid amide. 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 adipamide, 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 adipamide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamidoethyl 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.

[0063] 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 Above, 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 or less, preferably 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

[0064] 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.

[0065] The thickness of the substrate layer 1 is not particularly limited as long as it functions as a substrate, but may be, for example, about 3 μm or more, preferably about 10 μm or more, and may be, for example, about 100 μm or less, about 90 μm or less, about 70 μm or less, or about 50 μm or less, preferably about 35 μm or less, 11 μm or less, or 8 μm or less. In addition, preferred ranges of the thickness of the base layer 1 include about 3 to 100 μm, about 3 to 90 μm, about 3 to 70 μm, about 3 to 50 μm, about 3 to 35 μm, about 3 to 11 μm, about 3 to 8 μm, about 10 to 100 μm, about 10 to 90 μm, about 10 to 70 μm, about 10 to 50 μm, about 10 to 35 μm, and about 10 to 11 μm. In particular, when making the power storage device lighter and thinner, about 3 to 35 μm, about 3 to 11 μm, and about 3 to 8 μm are preferred, and when improving 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 the resin films constituting each layer is not particularly limited, but can be, for example, about 2 μm or more, preferably about 10 μm or more, or about 18 μm or more. The thickness of the resin film constituting each layer is, 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, or 8 μm or less. Preferred ranges for the thickness of the 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 10 to 11 μm, about 18 to 33 μm, about 18 to 28 μm, and about 18 to 23 μm.

[0066] The base material layer 1 contains a colorant, which allows the electrical storage device packaging material to be colored. 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.

[0067] 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 finely powdered mica and fish scale foil.

[0068] Among colorants, carbon black is preferred for making the exterior material for an electricity storage device black, and mica is preferred from the viewpoint of dissipating heat generated from the electricity storage device.

[0069] 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 with a laser diffraction / scattering particle size distribution analyzer.

[0070] The content of the colorant in the base layer 1 is not particularly limited as long as the packaging 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 %.

[0071] [Adhesive Layer 2] In the packaging material for an electricity storage device according to the present disclosure, the adhesive layer 2 is a layer that is provided between the base layer 1 and the barrier layer 3 as needed for the purpose of increasing the adhesion between them.

[0072] The adhesive layer 2 is formed from an adhesive capable of bonding the base material layer 1 and the barrier layer 3. There are no limitations on the adhesive used to form the adhesive layer 2, and it may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot pressure type, etc. It may also 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. The adhesive layer 2 may be a single layer or multiple layers.

[0073] Specific examples of adhesive components contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters; polyethers; polyurethanes; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolymer polyamides; polyolefin-based resins such as 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 with two or more. Among these adhesive components, polyurethane adhesives are preferred. Furthermore, the adhesive strength of these adhesive component resins can be increased by using an appropriate curing agent in combination. The curing agent is selected appropriately from polyisocyanates, multifunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, and the like, depending on the functional groups possessed by the adhesive components.

[0074] Examples of polyurethane adhesives include polyurethane adhesives containing a first part containing a polyol compound and a second part containing an isocyanate compound. Two-component curing polyurethane adhesives are preferred, with a polyol such as polyester polyol, polyether polyol, or acrylic polyol as the first part and an aromatic or aliphatic polyisocyanate as the second part. Examples of polyurethane adhesives include polyurethane adhesives containing a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance, and an isocyanate compound. Examples of polyurethane adhesives include polyurethane adhesives containing a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance, and a polyol compound. Examples of polyurethane adhesives include polyurethane adhesives obtained by reacting a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance with moisture, such as in the air, and then curing the polyurethane compound. Polyester polyols having hydroxyl groups on the side chains in addition to terminal hydroxyl groups in the repeating unit are preferably used as the polyol compound. Examples of the second part 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). Also included are polyfunctional isocyanate-modified compounds of one or more of these diisocyanates. Multimers (e.g., trimers) can also be used as polyisocyanate compounds. Examples of such multimers include adducts, biurets, and nurates. Forming the adhesive layer 2 using a polyurethane adhesive provides the electrical storage device exterior material with excellent electrolyte resistance, preventing peeling of the base layer 1 even when the electrolyte adheres to the side surface.

[0075] Furthermore, the adhesive layer 2 may contain other components as long as they do not impair adhesion, and may contain colorants, thermoplastic elastomers, tackifiers, fillers, etc. By including a colorant in the adhesive layer 2, the electrical storage device packaging material can be colored. Known colorants such as pigments and dyes can be used as colorants. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

[0076] 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 finely powdered mica and fish scale foil.

[0077] 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.

[0078] 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 with a laser diffraction / scattering particle size distribution analyzer.

[0079] The content of the colorant in the adhesive layer 2 is not particularly limited as long as it colors the packaging material for an electricity storage device, and may be, for example, about 5 to 60 mass %, and preferably 10 to 40 mass %.

[0080] 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. Preferred 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.

[0081] [Colored Layer] The colored layer is a layer (not shown) that is provided between the base material layer 1 and the barrier layer 3 as needed. 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. Alternatively, a colored layer may be provided on the outside of the base material layer 1. By providing a colored layer, the packaging material for an electricity storage device can be colored.

[0082] The colored layer can be formed, for example, by applying ink containing a colorant to the surface of the base layer 1 or the surface of the barrier layer 3. 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.

[0083] Specific examples of the colorant contained in the colored layer include the same as those exemplified in the section [Adhesive layer 2].

[0084] [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.

[0085] Examples of the barrier layer 3 include metal foils, vapor-deposited films, and resin layers having barrier properties. Vapor-deposited films include metal vapor-deposited films, inorganic oxide vapor-deposited films, and carbon-containing inorganic oxide vapor-deposited films. Resin layers include fluorine-containing resins such as polyvinylidene chloride, polymers mainly composed of chlorotrifluoroethylene (CTFE), polymers mainly composed of tetrafluoroethylene (TFE), polymers having fluoroalkyl groups, and polymers mainly composed of fluoroalkyl units, as well as ethylene-vinyl alcohol copolymers. Examples of the barrier layer 3 also include resin films comprising at least one of these vapor-deposited films and resin layers. The barrier layer 3 may include multiple layers. The barrier layer 3 preferably includes a layer composed of a metal material. Specific examples of metal materials constituting the barrier layer 3 include aluminum alloys, stainless steel, titanium steel, and steel plates. When used as a metal foil, the barrier layer 3 preferably includes at least one of aluminum alloy foil and stainless steel foil.

[0086] In the barrier layer 3, the layer made of the aforementioned metal material may contain recycled metal material. Examples of recycled metal material include recycled aluminum alloy, stainless steel, titanium steel, and steel plate. These recycled materials can be obtained by known methods. Recycled aluminum alloy material can be obtained, for example, by the manufacturing method described in International Publication No. 2022 / 092231. The barrier layer 3 may be made of recycled material alone, or may be made of a mixture of recycled and virgin material. Note that recycled metal material refers to metal material that has been made reusable by collecting, isolating, and refining various products used in the market or waste from manufacturing processes. Furthermore, virgin metal material refers to new metal material refined from natural metal resources (raw materials) and is not recycled material.

[0087] From the viewpoint of improving the formability of the electrical storage device packaging material, 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 formability, an iron-containing aluminum alloy foil is preferred. In the iron-containing aluminum alloy foil (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass. By having an iron content of 0.1% by mass or more, an electrical storage device packaging material with better formability can be obtained. By having an iron content of 9.0% by mass or less, an electrical storage device packaging material with better flexibility can be obtained. Examples of soft aluminum alloy foils include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Silicon, magnesium, copper, manganese, etc. may be added as needed. Softening can be achieved by annealing or other methods.

[0088] 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 that has excellent formability, the stainless steel foil is preferably made of austenitic stainless steel.

[0089] Specific examples of austenitic stainless steels that form the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

[0090] In the case of a metal foil, the thickness of the barrier layer 3 should be sufficient to at least function as a barrier layer that prevents moisture penetration, and may be, for example, approximately 9 to 200 μm. The thickness of the barrier layer 3 is preferably approximately 85 μm or less, more preferably approximately 60 μm or less, even more preferably approximately 40 μm or less, and particularly preferably approximately 35 μm or less. The thickness of the barrier layer 3 is preferably approximately 10 μm or more, even more preferably approximately 20 μm or more, and more preferably approximately 25 μm or more. Preferred thickness ranges for the barrier layer 3 include approximately 10 to 85 μm, approximately 10 to 60 μm, approximately 10 to 40 μm, approximately 10 to 35 μm, approximately 20 to 85 μm, approximately 20 to 60 μm, approximately 20 to 40 μm, approximately 20 to 35 μm, approximately 25 to 85 μm, approximately 25 to 60 μm, approximately 25 to 40 μm, and approximately 25 to 35 μm. When the barrier layer 3 is made of an aluminum alloy foil, the above-mentioned range is particularly preferable. From the viewpoint of imparting high formability and high rigidity to the packaging 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 also 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 approximately 35 to 200 μm, approximately 35 to 85 μm, approximately 35 to 75 μm, approximately 35 to 70 μm, approximately 45 to 200 μm, approximately 45 to 85 μm, approximately 45 to 75 μm, approximately 45 to 70 μm, approximately 50 to 200 μm, approximately 50 to 85 μm, approximately 50 to 75 μm, approximately 50 to 70 μm, approximately 55 to 200 μm, approximately 55 to 85 μm, approximately 55 to 75 μm, and approximately 55 to 70 μm. The high formability of the exterior packaging material 10 for an electricity storage device facilitates deep drawing, which can contribute to increasing the capacity of the electricity storage device. Furthermore, while increasing the capacity of an electricity storage device increases the weight of the electricity storage device, the increased rigidity of the exterior packaging 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 composed of a stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less. The thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. Preferred ranges for the thickness of the stainless steel foil include about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

[0091] Furthermore, when the barrier layer 3 is a metal foil, it is preferable that a corrosion-resistant coating be provided on at least the surface opposite the substrate layer to prevent dissolution and corrosion. The barrier layer 3 may be provided with a corrosion-resistant coating on both sides. Here, the corrosion-resistant coating refers to a thin film that is provided with corrosion resistance (e.g., acid resistance, alkali resistance, etc.) by performing, for example, a hydrothermal conversion treatment such as boehmite treatment, a chemical conversion treatment, an anodizing treatment, a plating treatment of nickel or chromium, or a corrosion prevention treatment by applying a coating agent on the surface of the barrier layer. Specifically, the corrosion-resistant coating refers to a coating that improves the acid resistance of the barrier layer (acid-resistant coating), a coating that improves the alkali resistance of the barrier layer (alkali-resistant coating), etc. The treatment for forming the corrosion-resistant coating may be one type or a combination of two or more types. Furthermore, not only one layer but also multiple layers can be formed. Furthermore, among these treatments, the hydrothermal conversion treatment and the anodizing treatment are treatments that dissolve the metal foil surface with 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 is provided with a corrosion-resistant coating, the barrier layer 3 includes the corrosion-resistant coating.

[0092] The corrosion-resistant coating prevents delamination between the barrier layer (e.g., aluminum alloy foil) and the substrate layer during molding of the electrical storage device packaging material, prevents dissolution and corrosion of the barrier layer surface due to hydrogen fluoride produced by a reaction between the electrolyte and water, 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 substrate layer and the barrier layer during heat sealing and molding.

[0093] Various corrosion-resistant coatings formed by chemical conversion treatments are known, including mainly corrosion-resistant coatings 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, phosphate chromate treatment, phosphate-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 acetylacetate, 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 paint-on chromate treatment, with paint-on chromate treatment being preferred. This paint-type chromate treatment involves first degreasing at least the inner surface of a barrier layer (e.g., an aluminum alloy foil) using a well-known method such as alkali immersion, electrolytic cleaning, acid pickling, electrolytic pickling, or acid activation, and then coating the degreased surface with a treatment solution containing, as its main component, a metal phosphate such as chromium (Cr) phosphate, titanium (Ti) phosphate, zirconium (Zr) phosphate, or zinc (Zn) phosphate, or a mixture of these metal salts, or a treatment solution containing, as its main component, a nonmetallic phosphate and a mixture of these nonmetallic salts, or a mixture of these with a synthetic resin, by a well-known coating method such as roll coating, gravure printing, or immersion, followed by drying. The treatment solution can be, for example, water, alcoholic solvents, hydrocarbon solvents, ketone solvents, ester solvents, or ether solvents, with water being 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). The aminated phenol polymer may contain one type of repeating unit represented by the following general formulas (1) to (4) alone, or two or more types of repeating units may be contained in any combination.The acrylic resin is preferably polyacrylic acid, an acrylic acid methacrylic acid ester copolymer, an acrylic acid maleic acid copolymer, an acrylic acid styrene copolymer, or a derivative thereof such as a sodium salt, an ammonium salt, or an amine salt. A derivative of polyacrylic acid, such as an ammonium salt, a sodium salt, or an amine salt of polyacrylic acid, is particularly preferred. In the present disclosure, polyacrylic acid refers to a polymer of acrylic acid. The acrylic resin is also preferably a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride, or an ammonium salt, a sodium salt, or an amine salt of a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride. Only one type of acrylic resin may be used, or two or more types may be mixed and used.

[0094]

[0095]

[0096]

[0097]

[0098] 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 are the same or different and represent a hydroxy group, an alkyl group, or a hydroxyalkyl group. 1 and R 2 Examples of the alkyl group represented by X and R include linear or branched alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl. 1 and R 2Examples of the hydroxyalkyl group represented by the formula (1) include a linear or branched alkyl group 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 hydroxyalkyl group represented by the formula (1) may be the same or different. In the 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 repeating units represented by the 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 comprising repeating units represented by the formula (1) or (3), and then polycondensing the polymer with formaldehyde and an amine (R 1 R 2 NH) to form a functional group (-CHNR 1 R 2 The aminated phenol polymers may be used singly or in combination of two or more.

[0099] Another example of a corrosion-resistant coating 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 a rare earth element oxide sol, an anionic polymer, and a cationic polymer is applied. The coating agent may further contain phosphoric acid or a phosphate salt, and a crosslinking agent for crosslinking the polymer. The rare earth element oxide sol contains rare earth element oxide fine particles (e.g., 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, with cerium oxide being preferred from the perspective of further improving adhesion. The rare earth element oxide contained in the corrosion-resistant coating can be used alone or in combination of two or more. Examples of liquid dispersion media 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, with water being preferred. Preferred examples of cationic polymers include polyethyleneimine, ionic polymer complexes consisting of polyethyleneimine and a polymer having a carboxylic acid, primary amine-grafted acrylic resins in which a primary amine is graft-polymerized onto an acrylic backbone, polyallylamine or its derivatives, and aminated phenols. Preferred anionic polymers include poly(meth)acrylic acid or its salts, or copolymers primarily composed of (meth)acrylic acid or its salts. The crosslinking agent is preferably at least one selected from the group consisting of a compound having a functional group selected from an isocyanate group, a glycidyl group, a carboxyl group, or an oxazoline group, and a silane coupling agent. The phosphoric acid or phosphoric acid salt is preferably a condensed phosphoric acid or a condensed phosphate salt.

[0100] An example of a corrosion-resistant coating is one formed by applying a solution in which fine particles of a metal oxide such as aluminum oxide, titanium oxide, cerium oxide, or tin oxide, or barium sulfate are dispersed in phosphoric acid to the surface of a barrier layer and then baking the coating at 150°C or higher.

[0101] The corrosion-resistant coating may have a laminated structure, if necessary, by further laminating at least one of a cationic polymer and an anionic polymer, such as those mentioned above.

[0102] The composition of the corrosion-resistant film can be analyzed by, for example, time-of-flight secondary ion mass spectrometry.

[0103] 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 a coating-type chromate treatment, the amount of the corrosion-resistant film formed on the surface of the barrier layer 3 is 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 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 in an amount, calculated as phosphorus, of about 1.0 to 200 mg, preferably about 5.0 to 150 mg, per 1000 ml of the aqueous solution.

[0104] The thickness of the corrosion-resistant coating 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 coating and the adhesive strength with the barrier layer and the thermally adhesive resin layer. The thickness of the corrosion-resistant coating can be measured by observation with a transmission electron microscope, or by 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 coating using time-of-flight secondary ion mass spectrometry can reveal, for example, the thickness of the corrosion-resistant coating consisting of secondary ions of Ce, P, and O (e.g., Ce2PO4 + , CePO4 - or at least one of ions of Cr, P, and O (e.g., CrPO2 + , CrPO4 - Peaks derived from at least one of the above are detected.

[0105] The chemical conversion treatment is carried out by applying a solution containing a compound used to form a corrosion-resistant coating to the surface of the barrier layer by bar coating, roll coating, gravure coating, immersion, or the like, and then heating the barrier layer to a temperature of about 70 to 200°C. Furthermore, before applying the chemical conversion treatment to the barrier layer, the barrier layer may be subjected to a degreasing treatment using an alkali immersion method, electrolytic cleaning, acid cleaning, electrolytic acid cleaning, or the like. By performing such a degreasing treatment, the chemical conversion treatment of the surface of the barrier layer can be carried out more efficiently. Furthermore, by using an acid degreasing agent prepared by dissolving a fluorine-containing compound 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, which is in a passive state. In such cases, only the degreasing treatment may be carried out.

[0106] [Heat-fusible resin layer 4] In the exterior packaging material for an electricity storage device of the present disclosure, the heat-fusible resin layer 4 corresponds to the innermost layer and is a layer (sealant layer) that exhibits the function of sealing the electricity storage device elements by heat-fusible resin layers being heat-fused together when the electricity storage device is assembled.

[0107] (Heat-sealable resin layer 4 of first embodiment) In a first embodiment of the present disclosure, the heat-sealable resin layer 4 of the electrical storage device packaging material has a logarithmic decrement ΔE of 0.075 or less at 150°C in rigid pendulum measurement. The electrical storage device packaging material of the first embodiment of the present disclosure can exhibit high sealing strength in an extremely high-temperature environment such as a 150°C environment, because the logarithmic decrement ΔE of the heat-sealable resin layer 4 in a 150°C environment is set to a very low value of 0.075 or less.

[0108] From the viewpoint of more suitably exerting the effects of the first aspect of the present disclosure, the logarithmic decrement ΔE of the heat-sealable resin layer 4 in an environment of 150° C. is preferably about 0.073 or less, more preferably 0.071 or less. If the logarithmic decrement ΔE is too low, the resin becomes hard, does not bend, and moldability deteriorates. Therefore, the logarithmic decrement ΔE is preferably about 0.020 or more, more preferably about 0.025 or more, even more preferably about 0.030 or more, 0.065 or more, or 0.069 or more, with preferred ranges being about 0.020 to 0.075, about 0.020 to 0.073, about 0.020 to 0.071, or 0.025 to 0.069. Examples of the logarithmic decrement ΔE of the heat-fusible resin layer 4 in a 150°C environment include about 0.075, about 0.025 to 0.073, about 0.025 to 0.071, about 0.030 to 0.075, about 0.030 to 0.073, about 0.030 to 0.071, about 0.065 to 0.075, about 0.065 to 0.073, about 0.065 to 0.071, about 0.069 to 0.075, about 0.069 to 0.073, and about 0.069 to 0.071. The logarithmic decrement ΔE of the heat-fusible resin layer 4 in a 150°C environment is a value measured by the method described in <Measurement of logarithmic decrement ΔE by rigid pendulum measurement> below.

[0109] <Measurement of logarithmic decrement ΔE by rigid pendulum measurement> A schematic diagram for explaining the method for measuring logarithmic decrement ΔE by rigid pendulum measurement is shown in Figure 6. A rigid pendulum-type physical property tester was used, with FRB-100 used for the frame of the pendulum 30, RBP-020 used for the cylindrical cylinder edge 30a of the edge portion, and CHB-100 used for the cooling block 31, and the initial amplitude was set to approximately 0.3 degrees. The pendulum adsorption time was set to 1.0 seconds, and the measurement interval was set to 10 seconds. The test sample was cut to MD 45 mm and TD 15 mm. In addition, a vibration displacement detector 32 was used.

[0110] The cylindrical cylinder edge RBP-020 used in this measurement has a small diameter of 2 mm, and is easily sunk from the surface to the interior of the heat-sealable resin layer during measurement, making it suitable for evaluating the overall characteristics of the heat-sealable resin layer in the thickness direction. Therefore, this measurement is suitable from the perspective of evaluating the correlation with the seal strength in the aforementioned high-temperature environment (150°C environment). For example, another cylinder edge is the cylindrical cylinder edge RBP-060, but this cylinder edge is cylindrical rather than columnar, and has a large diameter of 6 mm, making it difficult to sink into the interior, allowing for evaluation of the area near the surface.

[0111] The test sample was placed on a cooling block 31 with the measurement surface (thermal adhesive resin layer) facing upward, and the cylindrical cylinder edge 30a with a pendulum was placed on the measurement surface so that its axis was perpendicular to the MD direction of the test sample. To prevent the test sample from lifting or warping during measurement, tape was attached to a location on the cooling block 31 that would not affect the measurement results. The cylindrical cylinder edge 30a was brought into contact with the surface of the thermal adhesive resin layer. Next, the logarithmic decrement ΔE of the thermal adhesive resin layer was measured with N=1 using the cooling block 31 at a temperature rise rate of 3°C / min over a temperature range of 0°C to 180°C. The logarithmic decrement ΔE was measured when the surface temperature of the thermal adhesive resin layer of the test sample (exterior material for an electricity storage device) reached 150°C. In the first aspect of the present disclosure, the logarithmic decrement ΔE at 150°C in this measurement is used as an index for the heat-resistant seal strength at 150°C to be 25 N / 15 mm or more. The logarithmic decrement ΔE is calculated by the following formula: ΔE = [ln(A1 / A2) + ln(A2 / A3) + + ln(An / An+1)] / n, where A is amplitude and n is wave number.

[0112] For the heat-sealable resin layer 4 of the first embodiment, examples of a method for adjusting the logarithmic decrement ΔE at 150°C to 0.075 or less include a method for adjusting the composition of the heat-sealable resin layer 4, such as random polypropylene, homopolypropylene, or elastomer. In particular, the composition of the resin composition forming the heat-sealable resin layer 4 is a specific composition described later (the content of random polypropylene is preferably about 5% by mass or more, more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and also preferably about 35% by mass or less, more preferably about 30% by mass or less, and even more preferably about 20% by mass or less, with preferred ranges being about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, about 15 to 25% by mass, etc.; the content of homopolypropylene is preferably about 30% by mass or more, more preferably about 35% by mass or more, even more preferably about 40% by mass or more, and also preferably about 70% by mass or less, more preferably about 65% by mass or less, and even more preferably about 60% by mass or less, with preferred ranges being about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, about 15 to 25% by mass, etc.). The range is about 30 to 70 mass%, about 30 to 65 mass%, about 30 to 60 mass%, about 35 to 70 mass%, about 35 to 65 mass%, about 35 to 60 mass%, about 40 to 70 mass%, about 40 to 65 mass%, about 40 to 60 mass%, etc., and the elastomer content is preferably about 10 mass% or more, more preferably about 15 mass% or more, even more preferably about 20 mass% or more, and is preferably about 50 mass% or less, more preferably about The content is preferably about 45% by mass or less, more preferably about 40% by mass or less, and preferred ranges include about 10 to 50% by mass, about 10 to 45% by mass, about 10 to 40% by mass, about 15 to 50% by mass, about 15 to 45% by mass, about 15 to 40% by mass, about 20 to 50% by mass, about 20 to 45% by mass, and about 20 to 40% by mass), and by adjusting the content to satisfy this range, the logarithmic decrement ΔE of the heat-sealable resin layer 4 at 150°C tends to be 0.075 or less.

[0113] From the viewpoint of more suitably exerting the effects of the first aspect of the present disclosure, the logarithmic decrement ΔE of the heat-fusible resin layer 4 in an 80°C environment is preferably more than about 0.020, more preferably about 0.025 or more, even more preferably about 0.030 or more, and is preferably about 0.075 or less, more preferably about 0.073 or less, even more preferably about 0.071 or less. Preferred ranges include more than 0.020 and 0.075 or less, more than 0.020 and 0.073 or less, more than 0.020 and 0.071 or less, about 0.025 to 0.075, about 0.025 to 0.073, about 0.025 to 0.071, about 0.030 to 0.075, about 0.030 to 0.073, and about 0.030 to 0.071. The logarithmic attenuation factor ΔE of the heat-sealable resin layer 4 in an 80°C environment is a value measured in the same manner as the logarithmic attenuation factor ΔE of the heat-sealable resin layer 4 in an 80°C environment in the method described in the above <Measurement of logarithmic attenuation factor ΔE by rigid pendulum measurement>, except that "the logarithmic attenuation factor ΔE when the surface temperature of the heat-sealable resin layer of the test sample (exterior material for an electricity storage device) is used ...

[0114] In addition, from the viewpoint of more suitably exhibiting the effects of the first aspect of the present disclosure, the surface of the heat-sealable resin layer 4 is preferably provided with a 973 cm peak derived from an amorphous component in an absorption spectrum measured using an ATR measurement mode of FT-IR. -1 The peak intensity P1 near 998 cm originating from the crystalline component -1The intensity ratio X = P2 / P1 of the peak intensity P2 near is preferably about 0.750 or more, more preferably about 0.755 or more, and even more preferably about 0.760 or more. Furthermore, if the intensity ratio X is high and the crystallinity is too high, the material becomes difficult to elongate and its moldability deteriorates, so the intensity ratio X is preferably about 0.830 or less, more preferably about 0.825 or less, and even more preferably about 0.820 or less. Preferred ranges include about 0.750 to 0.830, about 0.750 to 0.825, about 0.750 to 0.820, about 0.755 to 0.830, about 0.755 to 0.825, about 0.755 to 0.820, about 0.760 to 0.830, about 0.760 to 0.825, and about 0.760 to 0.820. The intensity ratio X=P2 / P1 of the heat-fusible resin layer 4 is a value measured by the method described in <Evaluation of crystallinity by FT-IR> below.

[0115] <Evaluation of Crystallinity by FT-IR> The exterior material for an electricity storage device is cut into a 30 mm x 30 mm square to prepare a sample. The surface of the thermal adhesive resin layer of the obtained sample is subjected to infrared absorption spectrum measurement using the ATR measurement mode of FT / IR6100 under an environment of a temperature of 25°C and a relative humidity of 50%. From the obtained absorption spectrum, a 973 cm -1 The absorption peak intensity P1 near 998 cm originating from the crystalline component -1 The absorption peak intensity P2 near the absorption peak intensity P1 is measured, and the intensity ratio X of the absorption peak intensity P2 to the absorption peak intensity P1 is calculated as P2 / P1. Here, the infrared absorption spectrum uses absorbance values. Method: Macro ATR method Wavenumber resolution: 4 cm -1 Number of integrations: 32 times Detector: TGS detector ATR prism: Diamond Baseline: Wavenumber 927 cm -1 From 1067 cm -1 Absorption peak intensity P1: Wave number 973 cm -1 Absorption peak intensity P2: wave number 998 cm -1 The peak intensity in the vicinity minus the baseline value

[0116] For example, X-ray diffraction (XRD) has a detection depth of several tens of micrometers, and evaluates the crystallinity of not only the heat-sealable resin layer but also the adhesive layer. In contrast, the FT-IR ATR method has a detection depth of several micrometers, and reflects the crystallinity of only the heat-sealable resin layer. Therefore, the FT-IR ATR method can reflect the crystallinity of the heat-sealable resin layer, which is affected by the electrolyte.

[0117] For the heat-sealable resin layer 4 of the first embodiment, examples of a method for adjusting the intensity ratio X=P2 / P1 to be 0.760 or greater include a method of adjusting the composition, random polypropylene, homopolypropylene, elastomer, etc. of the heat-sealable resin layer 4. In particular, by adjusting the composition of the resin composition forming the heat-sealable resin layer 4 to satisfy the specific composition described below (a random polypropylene content of about 10 to 30% by mass (preferably about 15 to 25% by mass, etc.), a homopolypropylene content of about 30 to 70% by mass (preferably about 40 to 60% by mass, etc.), and an elastomer content of about 10 to 50% by mass (preferably about 20 to 40% by mass, etc.)), the intensity ratio X=P2 / P1 of the heat-sealable resin layer 4 is likely to be 0.760 or greater.

[0118] Furthermore, from the viewpoint of more suitably exerting the effects of the first aspect of the present disclosure, it is preferable that a sea-island structure be observed in a cross-sectional image of the heat-fusible resin layer 4 taken in a direction parallel to the TD and in the thickness direction, the cross-sectional image be obtained using a field emission scanning electron microscope, and that when the cross-sectional image is observed at a magnification of 20,000 times over an area of ​​4.50 μm × 6.37 μm, the number of island portions having a maximum diameter of 100 nm or more and less than 300 nm be 10 or less (more preferably 8 or less, and even more preferably 6 or less), and that no island portions having a maximum diameter of 300 nm or more be included. The cross-sectional image is measured by the method described in <Cross-Section Observation of Heat-Fusible Resin Layer> described later. The maximum diameter means the diameter in the major axis direction of the ellipse of the elliptical island portions observed with a scanning electron microscope.

[0119] Furthermore, from the viewpoint of more suitably exerting the effects of the first aspect of the present disclosure, it is preferable that crystalline lamellae be observed in the island portions when the island portions are observed in the cross-sectional image at a magnification of 50,000 times. In the first aspect of the present disclosure, the crystalline lamellae in the island portions are plate-like crystals formed by folding polymer chains, and are observed linearly within the island portions, with a thickness of, for example, about 10 to 20 nm and a length of, for example, about 50 to 200 nm (see FIGS. 9 and 15 ). The thickness of the crystalline lamellae observed in the island portions (see FIG. 15 ) is preferably 5 nm or more, more preferably 10 nm or more, and preferably 50 nm or less, more preferably 20 nm or less, with preferred ranges being about 5 to 50 nm, about 5 to 20 nm, about 10 to 50 nm, or about 10 to 20 nm. The length of the lamellae observed in the island portion (see FIG. 15) is preferably 10 nm or more, more preferably 20 nm or more, more preferably 50 nm or more, and is preferably 400 nm or less, more preferably 200 nm or less, and even more preferably 100 nm or less, with preferred ranges being about 10 to 400 nm, about 10 to 200 nm, about 10 to 100 nm, about 20 to 400 nm, about 20 to 200 nm, about 20 to 100 nm, about 50 to 400 nm, about 50 to 200 nm, and about 50 to 100 nm.

[0120] Furthermore, from the viewpoint of more suitably exerting the effects of the first aspect of the present disclosure, when a cross-sectional image of the island portion is observed at a magnification of 50,000 times, the island portion preferably does not have a layer having a thickness of 10 nm or more at the boundary between the island portion and the sea portion. In the first aspect of the present disclosure, the layer at the boundary between the island portion and the sea portion is a portion formed of a non-crystalline elastomer. Figure 9 shows an image (cross-sectional image obtained using a field emission scanning electron microscope) of an island portion having a layer having a thickness of 10 nm or more at the boundary between the island portion and the sea portion. The portion between the arrows in Figure 9 is a layer having a thickness of 10 nm or more at the boundary between the island portion and the sea portion, which is formed of a non-crystalline elastomer.

[0121] <Cross-sectional observation of the heat-sealable resin layer> The electrical storage device casing material is embedded in a thermosetting epoxy resin and cured. A cross-section is prepared using a commercially available rotary microtome, and the heat-sealable resin layer of the electrical storage device casing material, along with the embedded resin, is stained with ruthenium tetroxide for 3 hours. After cutting the cross-section 1 μm into pieces using the microtome, stained sections with thicknesses of 70 nm to 100 nm are obtained using a diamond knife. Cross-sectional images of the stained sections are obtained using a field emission scanning electron microscope. The measurement conditions are: acceleration voltage: 30 kV, emission current: 10 μA, detector: transmission detector, and no tilt (0°). The sea-island structure is observed at a magnification of 20,000x, and the lamellar structure is observed at a magnification of 50,000x. Specifically, for a cross-sectional image for observing the sea-island structure of the heat-fusible resin layer, a 4.50 μm × 6.37 μm range is randomly selected from a 13.5 μm × 19.1 μm range in the central portion of the heat-fusible resin layer at a magnification of 20,000 times to confirm the number of island portions contained in the 4.50 μm × 6.37 μm range. Further, the island portions observed at a magnification of 20,000 times are enlarged to a magnification of 50,000 times to observe whether or not the island portions have lamellae and whether or not the island portions have a layer with a thickness of 10 nm or more at the boundary between the island and sea portions.

[0122] The method for adjusting the heat-fusible resin layer 4 of the first embodiment so as to have the above-mentioned preferred sea-island structure includes a method for adjusting the composition of the heat-fusible resin layer 4, such as random polypropylene, homopolypropylene, elastomer, etc. In particular, the composition of the resin composition forming the heat-sealable resin layer 4 is the specific composition described below (the content of random polypropylene is preferably about 5% by mass or more, more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and also preferably about 35% by mass or less, more preferably about 30% by mass or less, and even more preferably about 20% by mass or less, and preferred ranges are about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, about 15 to 20% by mass, etc., and the content of homopolypropylene is preferably about 30% by mass or more, more preferably about 35% by mass or more, even more preferably about 40% by mass or more, and also preferably about 70% by mass or less, more preferably about 65% by mass or less, and even more preferably about 60% by mass or less, Preferred ranges include about 30 to 70% by mass, about 30 to 65% by mass, about 30 to 60% by mass, about 35 to 70% by mass, about 35 to 65% by mass, about 35 to 60% by mass, about 40 to 70% by mass, about 40 to 65% by mass, and about 40 to 60% by mass. The elastomer content is preferably about 10% by mass or more, more preferably about 15% by mass or more, even more preferably about 20% by mass or more, and is preferably about 50% by mass or less. , more preferably about 45% by mass or less, and even more preferably about 40% by mass or less, and preferred ranges include about 10 to 50% by mass, about 10 to 45% by mass, about 10 to 40% by mass, about 15 to 50% by mass, about 15 to 45% by mass, about 15 to 40% by mass, about 20 to 50% by mass, about 20 to 45% by mass, and about 20 to 40% by mass), thereby making it easier for the thermally adhesive resin layer 4 to have the preferred sea-island structure.

[0123] The resin constituting the heat-fusible resin layer 4 of the first embodiment is not particularly limited as long as it is heat-fusible and has a logarithmic decrement ΔE of 0.075 or less at 150°C in a rigid pendulum measurement. However, resins containing a polyolefin skeleton such as polyolefin and acid-modified polyolefin are preferred.

[0124] The presence of a polyolefin skeleton in the resin constituting the thermally adhesive resin layer 4 of the first embodiment can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, etc. Furthermore, when the resin constituting the thermally adhesive resin layer 4 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride is detected. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected at a wave number of 1760 cm. -1 Nearby and wave number 1780 cm -1 A peak derived from maleic anhydride is detected around . When the thermally adhesive resin layer 4 is a layer made of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected by infrared spectroscopy. However, if the degree of acid modification is low, the peak becomes small and may not be detected. In such cases, analysis can be performed by nuclear magnetic resonance spectroscopy.

[0125] The heat-sealable resin layer 4 of the first embodiment preferably contains a resin containing a polyolefin skeleton as a main component, more preferably a polyolefin as a main component, and even more preferably polypropylene as a main component. Here, "main component" refers to a resin component whose 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 contains polypropylene as a main component" means that the polypropylene 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.

[0126] 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. Polypropylene may be either a homopolymer or a copolymer. 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.

[0127] The polyolefin may also be a cyclic polyolefin. Cyclic polyolefins are copolymers of olefins and cyclic monomers, and examples of olefins constituting the cyclic polyolefins include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of cyclic monomers constituting the cyclic polyolefins 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.

[0128] The polyolefin may also be an acid-modified polyolefin. An acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of a polyolefin with an acid component. Examples of the acid-modified polyolefin include the above-mentioned polyolefins, copolymers of the above-mentioned polyolefins with polar molecules such as acrylic acid or methacrylic acid, and polymers such as crosslinked polyolefins. Examples of the acid component used for acid modification include carboxylic acids or anhydrides thereof, such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

[0129] 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 onto the cyclic polyolefin. The acid-modified cyclic polyolefin 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.

[0130] Preferred acid-modified polyolefins include polyolefins modified with carboxylic acid or its anhydride, polypropylenes modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

[0131] In the exterior packaging material for an electricity storage device according to the first aspect of the present disclosure, the logarithmic decrement ΔE at 150°C in a rigid pendulum measurement of the heat-sealable resin layer 4 is set to 0.075 or less, and from the viewpoint of enhancing heat resistance, the heat-sealable resin layer 4 is preferably formed from a resin composition containing random polypropylene, homopolypropylene, and an elastomer. The resin composition may contain block polypropylene, but from the viewpoint of more suitably exhibiting the effects of the first aspect of the present disclosure, it is preferable that the resin composition does not contain block polypropylene.

[0132] The thermally adhesive resin layer 4 of the first embodiment may be formed of one type of resin alone or 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.

[0133] From the viewpoint of more suitably exerting the effects of the first aspect of the present disclosure, the content of random polypropylene in the resin composition is preferably about 5% by mass or more, more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and is preferably about 35% by mass or less, more preferably about 30% by mass or less, even more preferably about 20% by mass or less. Preferred ranges include about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, and about 15 to 25% by mass.

[0134] Furthermore, from the viewpoint of more suitably exerting the effects of the first aspect of the present disclosure, the content of homopolypropylene in the resin composition is preferably about 30% by mass or more, more preferably about 35% by mass or more, even more preferably about 40% by mass or more, and is preferably about 70% by mass or less, more preferably about 65% by mass or less, even more preferably about 60% by mass or less. Preferred ranges include about 30 to 70% by mass, about 30 to 65% by mass, about 30 to 60% by mass, about 35 to 70% by mass, about 35 to 65% by mass, about 35 to 60% by mass, about 40 to 70% by mass, about 40 to 65% by mass, and about 40 to 60% by mass.

[0135] From the viewpoint of more suitably exerting the effects of the first aspect of the present disclosure, the content of the elastomer in the resin composition is preferably about 10% by mass or more, more preferably about 15% by mass or more, even more preferably about 20% by mass or more, and is preferably about 50% by mass or less, more preferably about 45% by mass or less, even more preferably about 40% by mass or less. Preferred ranges include about 10 to 50% by mass, about 10 to 45% by mass, about 10 to 40% by mass, about 15 to 50% by mass, about 15 to 45% by mass, about 15 to 40% by mass, about 20 to 50% by mass, about 20 to 45% by mass, and about 20 to 40% by mass.

[0136] From the viewpoint of more suitably exhibiting the effects of the first aspect of the present disclosure, the elastomer contained in the resin composition is preferably a binary copolymer or a tertiary copolymer. The elastomer is preferably a propylene-based elastomer. Examples of the propylene-based elastomer include binary copolymers and tertiary copolymers. Examples of binary copolymers include propylene-ethylene copolymer elastomers and propylene-butene copolymer elastomers, and examples of tertiary copolymers include propylene-ethylene-butene copolymer elastomers and ethylene-propylene-diene copolymer elastomers. Among the elastomers, a propylene-ethylene copolymer elastomer is preferred as the binary copolymer.

[0137] From the viewpoint of more suitably exerting the effects of the first aspect of the present disclosure, the specific composition of the resin composition may be, for example, a random polypropylene content of about 5% by mass or more (more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and also preferably about 35% by mass or less, more preferably about 30% by mass or less, and even more preferably about 20% by mass or less; preferred ranges include about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, and about 15 to 20% by mass), and a homopolypropylene content of about 30% by mass or more (more preferably about 35% by mass or more, even more preferably about 40% by mass or more, and also preferably about 70% by mass or less, more preferably about 65% by mass). % by mass or less, more preferably about 60% by mass or less, and preferred ranges include about 30 to 70% by mass, about 30 to 65% by mass, about 30 to 60% by mass, about 35 to 70% by mass, about 35 to 65% by mass, about 35 to 60% by mass, about 40 to 70% by mass, about 40 to 65% by mass, and about 40 to 60% by mass, and the elastomer content is about 10% by mass or more (more preferably about 15% by mass or more, and even more preferably The content is at least about 20% by mass, and is preferably not more than about 50% by mass, more preferably not more than about 45% by mass, and even more preferably not more than about 40% by mass, with preferred ranges being about 10 to 50% by mass, about 10 to 45% by mass, about 10 to 40% by mass, about 15 to 50% by mass, about 15 to 45% by mass, about 15 to 40% by mass, about 20 to 50% by mass, about 20 to 45% by mass, about 20 to 40% by mass, etc.) The resin composition is also preferably formed from a resin composition containing only random polypropylene, homopolypropylene, and elastomer as the resin (excluding additives such as lubricants described below).

[0138] (Heat-sealable resin layer 4 of second embodiment) In the heat-sealable resin layer 4 of the electrical storage device packaging material of the second embodiment of the present disclosure, a sea-island structure is observed in a cross-sectional image of the heat-sealable resin layer 4 taken using a field emission scanning electron microscope in a cross section parallel to the TD and in the thickness direction, and when the cross-sectional image is observed at a magnification of 20,000 times over an area of ​​4.50 μm × 6.37 μm, the number of island portions having a maximum diameter of 100 nm or more and less than 300 nm is 10 or less (more preferably 8 or less, even more preferably 6 or less), and no island portion having a maximum diameter of 300 nm or more is included. The cross-sectional image is measured by the method described in <Cross-sectional observation of heat-sealable resin layer> described later. The maximum diameter means the diameter in the major axis direction of the ellipse for elliptical island portions observed with a scanning electron microscope.

[0139] Furthermore, in the packaging material for an electricity storage device according to the second aspect of the present disclosure, when the island portions are observed at a magnification of 50,000 times in the cross-sectional image of the heat-fusible resin layer, crystalline lamellae are observed in the island portions. In the second aspect of the present disclosure, the crystalline lamellae in the island portions are plate-like crystals formed by folding polymer chains, and are observed linearly within the island portions, with thicknesses of 10 to 20 nm and lengths of 50 to 200 nm (see FIG. 15 ). The thickness of the crystalline lamellae observed in the island portions is preferably 5 nm or more, more preferably 10 nm or more, and is preferably 50 nm or less, more preferably 20 nm or less, with preferred ranges being about 5 to 50 nm, about 5 to 20 nm, about 10 to 50 nm, or about 10 to 20 nm. The length of the lamellae observed in the island portion is preferably 10 nm or more, more preferably 20 nm or more, more preferably 50 nm or more, and is preferably 400 nm or less, more preferably 200 nm or less, and even more preferably 100 nm or less, and preferred ranges are about 10 to 400 nm, about 10 to 200 nm, about 10 to 100 nm, about 20 to 400 nm, about 20 to 200 nm, about 20 to 100 nm, about 50 to 400 nm, about 50 to 200 nm, and about 50 to 100 nm.

[0140] Furthermore, from the viewpoint of more suitably exerting the effects of the second aspect of the present disclosure, when a cross-sectional image of the island portion is observed at a magnification of 50,000 times, the island portion preferably does not have a layer having a thickness of 10 nm or more at the boundary between the island portion and the sea portion. In the second aspect of the present disclosure, the layer at the boundary between the island portion and the sea portion is a portion formed of a non-crystalline elastomer. Figure 9 shows an image of an island portion having a layer having a thickness of 10 nm or more at the boundary between the island portion and the sea portion (a cross-sectional image obtained using a field emission scanning electron microscope). The portion between the arrows in Figure 9 is a layer having a thickness of 10 nm or more at the boundary between the island portion and the sea portion, which is formed of a non-crystalline elastomer.

[0141] The method for adjusting the heat-fusible resin layer 4 of the second embodiment so as to have the sea-island structure includes a method for adjusting the composition of the heat-fusible resin layer 4, such as random polypropylene, homopolypropylene, elastomer, etc. In particular, the composition of the resin composition forming the heat-sealable resin layer 4 is the specific composition described below (the content of random polypropylene is preferably about 5% by mass or more, more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and also preferably about 35% by mass or less, more preferably about 30% by mass or less, and even more preferably about 20% by mass or less, and preferred ranges are about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, about 15 to 20% by mass, etc., and the content of homopolypropylene is preferably about 30% by mass or more, more preferably about 35% by mass or more, even more preferably about 40% by mass or more, and also preferably about 70% by mass or less, more preferably about 65% by mass or less, and even more preferably about 60% by mass or less, Preferred ranges include about 30 to 70% by mass, about 30 to 65% by mass, about 30 to 60% by mass, about 35 to 70% by mass, about 35 to 65% by mass, about 35 to 60% by mass, about 40 to 70% by mass, about 40 to 65% by mass, and about 40 to 60% by mass. The elastomer content is preferably about 10% by mass or more, more preferably about 15% by mass or more, even more preferably about 20% by mass or more, and is preferably about 50% by mass or less. , more preferably about 45% by mass or less, and even more preferably about 40% by mass or less, and preferred ranges include about 10 to 50% by mass, about 10 to 45% by mass, about 10 to 40% by mass, about 15 to 50% by mass, about 15 to 45% by mass, about 15 to 40% by mass, about 20 to 50% by mass, about 20 to 45% by mass, and about 20 to 40% by mass), thereby making it easier for the thermally adhesive resin layer 4 to have the preferred sea-island structure.

[0142] <Cross-sectional observation of the heat-sealable resin layer> The electrical storage device casing material is embedded in a thermosetting epoxy resin and cured. A cross-section is prepared using a commercially available rotary microtome, and the heat-sealable resin layer of the electrical storage device casing material, along with the embedded resin, is stained with ruthenium tetroxide for 3 hours. After cutting the cross-section 1 μm into pieces using the microtome, stained sections with thicknesses of 70 nm to 100 nm are obtained using a diamond knife. Cross-sectional images of the stained sections are obtained using a field emission scanning electron microscope. The measurement conditions are: acceleration voltage: 30 kV, emission current: 10 μA, detector: transmission detector, and no tilt (0°). The sea-island structure is observed at a magnification of 20,000x, and the lamellar structure is observed at a magnification of 50,000x. Specifically, for a cross-sectional image for observing the sea-island structure of the heat-fusible resin layer, a 4.50 μm × 6.37 μm range is randomly selected from a 13.5 μm × 19.1 μm range in the central portion of the heat-fusible resin layer at a magnification of 20,000 times to confirm the number of island portions contained in the 4.50 μm × 6.37 μm range. Further, the island portions observed at a magnification of 20,000 times are enlarged to a magnification of 50,000 times to observe whether or not the island portions have lamellae and whether or not the island portions have a layer with a thickness of 10 nm or more at the boundary between the island and sea portions.

[0143] Furthermore, the heat-fusible resin layer 4 of the packaging material for an electricity storage device of the second embodiment has a logarithmic decrement ΔE at 150°C in rigid pendulum measurement of preferably 0.075 or less, more preferably about 0.073 or less, and even more preferably about 0.071 or less. If the logarithmic decrement ΔE is too low, the material becomes hard, does not bend, and formability deteriorates; therefore, the logarithmic decrement ΔE is preferably about 0.020 or more, more preferably about 0.025 or more, and even more preferably about 0.030 or more. Preferred ranges include about 0.020 to 0.075, about 0.020 to 0.073, about 0.020 to 0.071, about 0.025 to 0.075, about 0.025 to 0.073, about 0.025 to 0.071, about 0.030 to 0.075, about 0.030 to 0.073, and about 0.030 to 0.071. In the electrical storage device packaging material according to the second aspect of the present disclosure, the logarithmic decrement ΔE of the heat-sealable resin layer 4 in an environment at 150° C. is set to a very low value of 0.075 or less, and therefore high sealing strength can be exhibited in an environment as very high as 150° C. The logarithmic decrement ΔE of the heat-sealable resin layer 4 in an environment at 150° C. is a value measured by the method described in <Measurement of logarithmic decrement ΔE by rigid pendulum measurement> below.

[0144] <Measurement of logarithmic decrement ΔE by rigid pendulum measurement> A schematic diagram for explaining the method for measuring logarithmic decrement ΔE by rigid pendulum measurement is shown in Figure 6. A rigid pendulum-type physical property tester was used, with FRB-100 used for the frame of the pendulum 30, RBP-020 used for the cylindrical cylinder edge 30a of the edge portion, and CHB-100 used for the cooling block 31, and the initial amplitude was set to approximately 0.3 degrees. The pendulum adsorption time was set to 1.0 seconds, and the measurement interval was set to 10 seconds. The test sample was cut to MD 45 mm and TD 15 mm. In addition, a vibration displacement detector 32 was used.

[0145] The cylindrical cylinder edge RBP-020 used in this measurement has a small diameter of 2 mm, and is easily sunk from the surface to the interior of the heat-sealable resin layer during measurement, making it suitable for evaluating the overall characteristics of the heat-sealable resin layer in the thickness direction. Therefore, this measurement is suitable from the perspective of evaluating the correlation with the seal strength in a high-temperature environment (150°C environment) described below. For example, another cylinder edge is the cylindrical cylinder edge RBP-060, but this cylinder edge is cylindrical rather than columnar, and has a large diameter of 6 mm, making it difficult to sink into the interior, allowing for evaluation of the area near the surface.

[0146] The test sample was placed on a cooling block 31 with the measurement surface (thermal adhesive resin layer) facing upward, and the cylindrical cylinder edge 30a with a pendulum was placed on the measurement surface so that its axis was perpendicular to the MD direction of the test sample. To prevent the test sample from lifting or warping during measurement, tape was attached to a location on the cooling block 31 that would not affect the measurement results. The cylindrical cylinder edge 30a was brought into contact with the surface of the thermal adhesive resin layer. Next, the logarithmic decrement ΔE of the thermal adhesive resin layer was measured with N=1 using the cooling block 31 at a temperature rise rate of 3°C / min over a temperature range of 0°C to 180°C. The logarithmic decrement ΔE was measured when the surface temperature of the thermal adhesive resin layer of the test sample (exterior material for an electricity storage device) reached 150°C. In the second aspect of the present disclosure, the logarithmic decrement ΔE at 150°C in this measurement is used as an index for indicating that the heat-resistant seal strength at 150°C is 25 N / 15 mm or more. The logarithmic decrement ΔE is calculated by the following formula: ΔE = [ln(A1 / A2) + ln(A2 / A3) + + ln(An / An+1)] / n, where A is amplitude and n is wave number.

[0147] For the heat-sealable resin layer 4 of the second embodiment, examples of a method for adjusting the logarithmic decrement ΔE at 150°C to 0.075 or less include a method for adjusting the composition of the heat-sealable resin layer 4, such as random polypropylene, homopolypropylene, or elastomer. In particular, the composition of the resin composition forming the heat-sealable resin layer 4 is a specific composition described later (the content of random polypropylene is preferably about 5% by mass or more, more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and also preferably about 35% by mass or less, more preferably about 30% by mass or less, and even more preferably about 20% by mass or less, with preferred ranges being about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, about 15 to 20% by mass, etc.; the content of homopolypropylene is preferably about 30% by mass or more, more preferably about 35% by mass or more, even more preferably about 40% by mass or more, and also preferably about 70% by mass or less, more preferably about 65% by mass or less, and even more preferably about 60% by mass or less, with preferred ranges being about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, and about 15 to 20% by mass). The range is about 30 to 70 mass%, about 30 to 65 mass%, about 30 to 60 mass%, about 35 to 70 mass%, about 35 to 65 mass%, about 35 to 60 mass%, about 40 to 70 mass%, about 40 to 65 mass%, about 40 to 60 mass%, etc., and the elastomer content is preferably about 10 mass% or more, more preferably about 15 mass% or more, even more preferably about 20 mass% or more, and is preferably about 50 mass% or less, more preferably about The content is preferably about 45% by mass or less, more preferably about 40% by mass or less, and preferred ranges include about 10 to 50% by mass, about 10 to 45% by mass, about 10 to 40% by mass, about 15 to 50% by mass, about 15 to 45% by mass, about 15 to 40% by mass, about 20 to 50% by mass, about 20 to 45% by mass, and about 20 to 40% by mass), and by adjusting the content to satisfy this range, the logarithmic decrement ΔE of the heat-sealable resin layer 4 at 150°C tends to be 0.075 or less.

[0148] From the viewpoint of more suitably exerting the effects of the second aspect of the present disclosure, the logarithmic decrement ΔE of the heat-fusible resin layer 4 in an 80°C environment is preferably more than about 0.020, more preferably about 0.025 or more, even more preferably 0.030 or more, and is preferably about 0.065 or less, more preferably about 0.060 or less, even more preferably about 0.055 or less. Preferred ranges include more than 0.020 and 0.065 or less, more than 0.020 and 0.060 or less, more than 0.020 and 0.055 or less, about 0.025 to 0.065, about 0.025 to 0.060, about 0.025 to 0.055, about 0.030 to 0.065, about 0.030 to 0.060, and about 0.030 to 0.055. The logarithmic attenuation factor ΔE of the heat-sealable resin layer 4 in an 80°C environment is a value measured in the same manner as the logarithmic attenuation factor ΔE of the heat-sealable resin layer 4 in an 80°C environment in the method described in the above <Measurement of logarithmic attenuation factor ΔE by rigid pendulum measurement>, except that "the logarithmic attenuation factor ΔE when the surface temperature of the heat-sealable resin layer of the test sample (exterior material for an electricity storage device) is used ...

[0149] The resin constituting the heat-fusible resin layer 4 of the second embodiment is not particularly limited as long as it is heat-fusible and has the above-mentioned sea-island structure, but resins containing a polyolefin skeleton, such as polyolefin and acid-modified polyolefin, are preferred. The presence of a polyolefin skeleton in the resin constituting the heat-fusible resin layer 4 can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like. Furthermore, when the resin constituting the heat-fusible resin layer 4 is analyzed by infrared spectroscopy, a peak derived from maleic anhydride is preferably detected. For example, when a maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected at a wavenumber of 1760 cm. -1 Nearby and wave number 1780 cm -1A peak derived from maleic anhydride is detected around . When the thermally adhesive resin layer 4 is a layer made of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected by infrared spectroscopy. However, if the degree of acid modification is low, the peak becomes small and may not be detected. In such cases, analysis can be performed by nuclear magnetic resonance spectroscopy.

[0150] The heat-sealable resin layer 4 of the second embodiment preferably contains a resin containing a polyolefin skeleton as a main component, more preferably a polyolefin as a main component, and even more preferably polypropylene as a main component. Here, "main component" refers to a resin component whose 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 contains polypropylene as a main component" means that the polypropylene 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.

[0151] 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. Polypropylene may be either a homopolymer or a copolymer. 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.

[0152] The polyolefin may also be a cyclic polyolefin. Cyclic polyolefins are copolymers of olefins and cyclic monomers, and examples of olefins constituting the cyclic polyolefins include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of cyclic monomers constituting the cyclic polyolefins 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.

[0153] The polyolefin may also be an acid-modified polyolefin. An acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of a polyolefin with an acid component. Examples of the acid-modified polyolefin include the above-mentioned polyolefins, copolymers of the above-mentioned polyolefins with polar molecules such as acrylic acid or methacrylic acid, and polymers such as crosslinked polyolefins. Examples of the acid component used for acid modification include carboxylic acids or anhydrides thereof, such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

[0154] 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 onto the cyclic polyolefin. The acid-modified cyclic polyolefin 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.

[0155] Preferred acid-modified polyolefins include polyolefins modified with carboxylic acid or its anhydride, polypropylenes modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

[0156] In the electrical storage device packaging material according to the second aspect of the present disclosure, the thermally adhesive resin layer 4 is preferably formed from a resin composition containing random polypropylene, homopolypropylene, and an elastomer, from the viewpoint of forming the above-described sea-island structure. The resin composition may contain block polypropylene, but from the viewpoint of more suitably exhibiting the effects of the second aspect of the present disclosure, it is preferable that the resin composition does not contain block polypropylene.

[0157] The thermally adhesive resin layer 4 of the second embodiment may be formed of one type of resin alone or 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.

[0158] From the viewpoint of more suitably exerting the effects of the second aspect of the present disclosure, the content of random polypropylene in the resin composition is preferably about 5% by mass or more, more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and is preferably about 35% by mass or less, more preferably about 30% by mass or less, even more preferably about 20% by mass or less. Preferred ranges include about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, and about 15 to 25% by mass.

[0159] Furthermore, from the viewpoint of more suitably exerting the effects of the second aspect of the present disclosure, the content of homopolypropylene in the resin composition is preferably about 30% by mass or more, more preferably about 35% by mass or more, even more preferably about 40% by mass or more, and is preferably about 70% by mass or less, more preferably about 65% by mass or less, even more preferably about 60% by mass or less. Preferred ranges include about 30 to 70% by mass, about 30 to 65% by mass, about 30 to 60% by mass, about 35 to 70% by mass, about 35 to 65% by mass, about 35 to 60% by mass, about 40 to 70% by mass, about 40 to 65% by mass, and about 40 to 60% by mass.

[0160] From the viewpoint of more suitably exerting the effects of the second aspect of the present disclosure, the content of the elastomer in the resin composition is preferably about 10% by mass or more, more preferably about 15% by mass or more, even more preferably about 20% by mass or more, and is preferably about 50% by mass or less, more preferably about 45% by mass or less, even more preferably about 40% by mass or less. Preferred ranges include about 10 to 50% by mass, about 10 to 45% by mass, about 10 to 40% by mass, about 15 to 50% by mass, about 15 to 45% by mass, about 15 to 40% by mass, about 20 to 50% by mass, about 20 to 45% by mass, and about 20 to 40% by mass.

[0161] In the second aspect of the present disclosure, the term "elastomer" refers to a soft polymer having elasticity like rubber. From the viewpoint of more suitably exhibiting the effects of the second aspect of the present disclosure, the elastomer is preferably a binary copolymer or a tertiary copolymer. The elastomer is also preferably a propylene-based elastomer. Examples of the propylene-based elastomer include binary copolymers and tertiary copolymers. Examples of binary copolymers include propylene-ethylene copolymer elastomers and propylene-butene copolymer elastomers, and examples of tertiary copolymers include propylene-ethylene-butene copolymer elastomers and ethylene-propylene-diene copolymer elastomers. Among the elastomers, a propylene-ethylene copolymer elastomer is preferred as a binary copolymer.

[0162] From the viewpoint of more suitably exerting the effects of the second aspect of the present disclosure, the specific composition of the resin composition may be, for example, a random polypropylene content of about 5% by mass or more (more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and also preferably about 35% by mass or less, more preferably about 30% by mass or less, and even more preferably about 20% by mass or less; preferred ranges include about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, and about 15 to 25% by mass), and a homopolypropylene content of about 30% by mass or more (more preferably about 35% by mass or more, even more preferably about 40% by mass or more, and also preferably about 70% by mass or less, more preferably about 65% by mass). % by mass or less, more preferably about 60% by mass or less, and preferred ranges include about 30 to 70% by mass, about 30 to 65% by mass, about 30 to 60% by mass, about 35 to 70% by mass, about 35 to 65% by mass, about 35 to 60% by mass, about 40 to 70% by mass, about 40 to 65% by mass, and about 40 to 60% by mass, and the elastomer content is about 10% by mass or more (more preferably about 15% by mass or more, and even more preferably The content is at least about 20% by mass, and is preferably not more than about 50% by mass, more preferably not more than about 45% by mass, and even more preferably not more than about 40% by mass, with preferred ranges being about 10 to 50% by mass, about 10 to 45% by mass, about 10 to 40% by mass, about 15 to 50% by mass, about 15 to 45% by mass, about 15 to 40% by mass, about 20 to 50% by mass, about 20 to 45% by mass, about 20 to 40% by mass, etc.) The resin composition is also preferably formed from a resin composition containing only random polypropylene, homopolypropylene, and elastomer as the resin (excluding additives such as lubricants described below).

[0163] (Heat-sealable resin layer 4 of third aspect) In a third aspect of the present disclosure, the heat-sealable resin layer 4 of the electrical storage device packaging material has, in a DSC curve obtained by differential scanning calorimetry, a melting peak temperature of 160.0°C or higher, no shoulder peak in the temperature range of 100.0°C or higher and 150.0°C or lower, and a shoulder peak at a temperature above 150.0°C. The electrical storage device packaging material of the third aspect of the present disclosure can exhibit excellent heat resistance and insulating properties in high-temperature environments because the DSC curve of the heat-sealable resin layer 4 has these characteristics. The DSC curve is obtained by the method described below.

[0164] From the viewpoint of more suitably exerting the effects of the third aspect of the present disclosure, the melting peak temperature of the heat-fusible resin layer 4 is preferably about 160.0°C or higher, more preferably about 162.0°C or higher, and even more preferably about 164.0°C or higher. The upper limit is, for example, about 180.0°C or lower, and preferred ranges include about 160.0 to 180.0°C, about 162.0 to 180.0°C, and about 164.0 to 180.0°C.

[0165] Furthermore, from the viewpoint of more suitably exerting the effects of the third aspect of the present disclosure, the temperature at which a shoulder peak exists in the DSC curve (shoulder peak temperature) is preferably about 152.0°C or higher, more preferably about 154.0°C or higher, and the upper limit is, for example, about 165.0°C or lower. Preferred ranges include higher than 150.0°C and 165.0°C or lower, about 152.0 to 165.0°C, and about 154.0 to 165.0°C.

[0166] Regarding the heat-fusible resin layer 4 of the third embodiment, examples of a method for adjusting the DSC curve so that it has the above-mentioned characteristics (a melting peak temperature of 160.0°C or higher, no shoulder peak in the temperature range of 100.0°C or higher and 150.0°C or lower, and a shoulder peak at a temperature above 150.0°C) include a method for adjusting the composition of the heat-fusible resin layer 4, random polypropylene, homopolypropylene, elastomer, etc. In particular, the composition of the resin composition forming the heat-sealable resin layer 4 is preferably a specific composition described later (the content of random polypropylene is preferably about 5% by mass or more, more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and also preferably about 35% by mass or less, more preferably about 30% by mass or less, and even more preferably about 20% by mass or less, with preferred ranges being about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, about 15 to 20% by mass, etc.; the content of homopolypropylene is preferably about 30% by mass or more, more preferably about 35% by mass or more, even more preferably about 40% by mass or more, and also preferably about 70% by mass or less, more preferably about 65% by mass or less, and even more preferably about 60% by mass or less, Preferred ranges include about 30 to 70% by mass, about 30 to 65% by mass, about 30 to 60% by mass, about 35 to 70% by mass, about 35 to 65% by mass, about 35 to 60% by mass, about 40 to 70% by mass, about 40 to 65% by mass, and about 40 to 60% by mass. The elastomer content is preferably about 10% by mass or more, more preferably about 15% by mass or more, and even more preferably about 20% by mass or more, and is preferably about 50% by mass or less. It is more preferably about 45% by mass or less, and even more preferably about 40% by mass or less, and preferred ranges include about 10 to 50% by mass, about 10 to 45% by mass, about 10 to 40% by mass, about 15 to 50% by mass, about 15 to 45% by mass, about 15 to 40% by mass, about 20 to 50% by mass, about 20 to 45% by mass, and about 20 to 40% by mass), so that the DSC curve of the heat-fusible resin layer 4 is more likely to satisfy the above-mentioned characteristics.

[0167] <Evaluation of heat-sealable resin layer by differential scanning calorimetry (obtaining a DSC curve)> For the heat-sealable resin layer of the exterior material for an electricity storage device, a DSC curve of the resin forming the heat-sealable resin layer is obtained by differential scanning calorimetry (DSC) in accordance with the provisions of JIS K7121:2012 (Method for measuring transition temperature of plastics). 5-10 mg of the heat-sealable resin layer is placed in an aluminum pan, covered, and then a DSC curve is obtained using a differential scanning calorimeter (Shimadzu DSC-60). The measurement was carried out in a temperature range from -10 ° C to 200 ° C at a heating rate of 10 ° C / min and a cooling rate of -10 ° C / min. Once 200 ° C was reached, the temperature was held at 200 ° C for 10 minutes, and then further cooled to -10 ° C for 10 minutes. This eliminates the thermal history and allows the performance of the resin itself to be examined. A DSC curve is obtained from the second heating after one heating and cooling. From the obtained DSC curve, the melting peak temperature of the heat-fusible resin layer and the shoulder peak in the temperature range above 100.0 ° C were confirmed. The measurement was carried out in a nitrogen atmosphere with a nitrogen gas flow rate of 50 mL / min. The melting peak temperature and shoulder peak temperature are values ​​rounded to one decimal place. The shoulder peak is the portion of the DSC curve in the temperature range from the extrapolated melting onset temperature to the melting peak temperature, where the slope of the curve changes on the lower side than the melting peak temperature. It is also called a shoulder peak. The shoulder peak temperature is preferably determined as follows (i) and (ii) with reference to JIS K7121 (Method for measuring transition temperatures of plastics): (i) The shoulder peak temperature is the temperature at the apex of the shoulder peak. (ii) If the shoulder peak temperature is gentle and it is difficult to determine the apex, the shoulder peak temperature is the temperature at the intersection of a tangent drawn at the point where the gradient is maximum on the curve on the low-temperature side of the shoulder peak and a tangent drawn at the point where the gradient is minimum on the curve on the high-temperature side of the shoulder peak.

[0168] Furthermore, from the viewpoint of more suitably exerting the effects of the third aspect of the present disclosure, the logarithmic decrement ΔE of the heat-sealable resin layer 4 in a 150°C environment is preferably 0.075 or less, more preferably about 0.073 or less, and even more preferably about 0.071 or less. If the logarithmic decrement ΔE is too low, the layer becomes hard, does not bend, and moldability deteriorates. Therefore, the logarithmic decrement ΔE is preferably about 0.020 or more, more preferably about 0.025 or more, and even more preferably about 0.030 or more. Preferred ranges include about 0.020 to 0.075, about 0.020 to 0.073, about 0.020 to 0.071, about 0.025 to 0.075, about 0.025 to 0.073, about 0.025 to 0.071, about 0.030 to 0.075, about 0.030 to 0.073, and about 0.030 to 0.071. In the packaging material for an electricity storage device according to the third aspect of the present disclosure, the logarithmic decrement ΔE of the heat-sealable resin layer 4 in an environment of 150° C. is set to a very low value of 0.075 or less, and therefore the packaging material can exhibit high sealing strength in an environment of a very high temperature of 150° C. The logarithmic decrement ΔE of the heat-sealable resin layer 4 in an environment of 150° C. is a value measured by the method described in <Measurement of logarithmic decrement ΔE by rigid pendulum measurement> below.

[0169] <Measurement of logarithmic decrement ΔE by rigid pendulum measurement> A schematic diagram for explaining the method for measuring logarithmic decrement ΔE by rigid pendulum measurement is shown in Figure 6. A rigid pendulum-type physical property tester was used, with FRB-100 used for the frame of the pendulum 30, RBP-020 used for the cylindrical cylinder edge 30a of the edge portion, and CHB-100 used for the cooling block 31, and the initial amplitude was set to approximately 0.3 degrees. The pendulum adsorption time was set to 1.0 seconds, and the measurement interval was set to 10 seconds. The test sample was cut to MD 45 mm and TD 15 mm. In addition, a vibration displacement detector 32 was used.

[0170] The cylindrical cylinder edge RBP-020 used in this measurement has a small diameter of 2 mm, and is easily sunk from the surface to the interior of the heat-sealable resin layer during measurement, making it suitable for evaluating the overall characteristics of the heat-sealable resin layer in the thickness direction. Therefore, this measurement is suitable from the perspective of evaluating the correlation with the seal strength in a high-temperature environment (150°C environment) described below. For example, another cylinder edge is the cylindrical cylinder edge RBP-060, but this cylinder edge is cylindrical rather than columnar, and has a large diameter of 6 mm, making it difficult to sink into the interior, allowing for evaluation of the area near the surface.

[0171] The test sample was placed on a cooling block 31 with the measurement surface (thermal adhesive resin layer) facing upward, and the cylindrical cylinder edge 30a with a pendulum was placed on the measurement surface so that its axis was perpendicular to the MD direction of the test sample. To prevent the test sample from lifting or warping during measurement, tape was attached to a location on the cooling block 31 that would not affect the measurement results. The cylindrical cylinder edge 30a was brought into contact with the surface of the thermal adhesive resin layer. Next, the logarithmic decrement ΔE of the thermal adhesive resin layer was measured with N=1 using the cooling block 31 at a temperature rise rate of 3°C / min over a temperature range of 0°C to 180°C. The logarithmic decrement ΔE was measured when the surface temperature of the thermal adhesive resin layer of the test sample (exterior material for an electricity storage device) reached 150°C. In the third aspect of the present disclosure, the logarithmic decrement ΔE at 150°C in this measurement is used as an index for indicating that the heat-resistant seal strength at 150°C is 25 N / 15 mm or more. The logarithmic decrement ΔE is calculated using the following formula. In this calculation, the value is rounded to the third decimal place to calculate the value to the third decimal place. ΔE = [ln(A1 / A2) + ln(A2 / A3) + . . . + ln(An / An+1)] / n, where A is amplitude and n is wave number.

[0172] Regarding the heat-sealable resin layer 4 of the third embodiment, a method for adjusting the logarithmic decrement ΔE at 150°C to 0.075 or less includes adjusting the composition of the heat-sealable resin layer 4 (the content of random polypropylene is preferably about 5% by mass or more, more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and also preferably about 35% by mass or less, more preferably about 30% by mass or less, and even more preferably about 20% by mass or less, and preferred ranges are about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, about 15 to 20% by mass, and the content of homopolypropylene is preferably about 30% by mass or more, more preferably about 35% by mass or more, and even more preferably about 40% by mass or more, and also preferably about 70% by mass or less, more preferably about 65% by mass or less, and even more preferably about The elastomer content is preferably about 10% by mass or more, more preferably about 15% by mass or more, and even more preferably about 20% by mass or more, and is preferably about 50% by mass or less. , more preferably about 45% by mass or less, and even more preferably about 40% by mass or less, and preferred ranges include about 10 to 50% by mass, about 10 to 45% by mass, about 10 to 40% by mass, about 15 to 50% by mass, about 15 to 45% by mass, about 15 to 40% by mass, about 20 to 50% by mass, about 20 to 45% by mass, and about 20 to 40% by mass), the logarithmic decrement ΔE of the heat-fusible resin layer 4 at 150°C is likely to be 0.075 or less.

[0173] From the viewpoint of more suitably exerting the effects of the third aspect of the present disclosure, the logarithmic decrement ΔE of the heat-fusible resin layer 4 in an 80°C environment is preferably more than about 0.020, more preferably about 0.025 or more, even more preferably 0.030 or more, and is preferably about 0.065 or less, more preferably about 0.060 or less, even more preferably about 0.055 or less. Preferred ranges include more than 0.020 and 0.065 or less, more than 0.020 and 0.060 or less, more than 0.020 and 0.055 or less, about 0.025 to 0.065, about 0.025 to 0.060, about 0.025 to 0.055, about 0.030 to 0.065, about 0.030 to 0.060, and about 0.030 to 0.055. The logarithmic attenuation factor ΔE of the heat-sealable resin layer 4 in an 80°C environment is a value measured in the same manner as the logarithmic attenuation factor ΔE of the heat-sealable resin layer 4 in an 80°C environment in the method described in the above <Measurement of logarithmic attenuation factor ΔE by rigid pendulum measurement>, except that "the logarithmic attenuation factor ΔE when the surface temperature of the heat-sealable resin layer of the test sample (exterior material for an electricity storage device) is used ...

[0174] The resin constituting the heat-sealable resin layer 4 of the third embodiment is not particularly limited, as long as it is heat-sealable and has a melting peak temperature of 160.0°C or higher in a DSC curve, no shoulder peak in the temperature range of 100.0°C to 150.0°C, and a shoulder peak at temperatures above 150.0°C. However, resins containing a polyolefin skeleton, such as polyolefins and acid-modified polyolefins, are preferred. The presence of a polyolefin skeleton in the resin constituting the heat-sealable resin layer 4 can be determined by, for example, infrared spectroscopy or gas chromatography-mass spectrometry. Furthermore, when the resin constituting the heat-sealable resin layer 4 is analyzed by infrared spectroscopy, a peak derived from maleic anhydride is preferably detected. For example, when a maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected at a wavenumber of 1760 cm. -1 Nearby and wave number 1780 cm -1A peak derived from maleic anhydride is detected around . When the thermally adhesive resin layer 4 is a layer made of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected by infrared spectroscopy. However, if the degree of acid modification is low, the peak becomes small and may not be detected. In such cases, analysis can be performed by nuclear magnetic resonance spectroscopy.

[0175] The heat-sealable resin layer 4 of the third embodiment preferably contains a resin containing a polyolefin skeleton as a main component, more preferably a polyolefin as a main component, and even more preferably polypropylene as a main component. Here, "main component" refers to a resin component whose 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 contains polypropylene as a main component" means that the polypropylene 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.

[0176] 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. Polypropylene may be either a homopolymer or a copolymer. 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.

[0177] The polyolefin may also be a cyclic polyolefin. Cyclic polyolefins are copolymers of olefins and cyclic monomers, and examples of olefins constituting the cyclic polyolefins include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of cyclic monomers constituting the cyclic polyolefins 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.

[0178] The polyolefin may also be an acid-modified polyolefin. An acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of a polyolefin with an acid component. Examples of the acid-modified polyolefin include the above-mentioned polyolefins, copolymers of the above-mentioned polyolefins with polar molecules such as acrylic acid or methacrylic acid, and polymers such as crosslinked polyolefins. Examples of the acid component used for acid modification include carboxylic acids or anhydrides thereof, such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

[0179] 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 onto the cyclic polyolefin. The acid-modified cyclic polyolefin 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.

[0180] Preferred acid-modified polyolefins include polyolefins modified with carboxylic acid or its anhydride, polypropylenes modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

[0181] In the electrical storage device packaging material of the third aspect of the present disclosure, from the viewpoint of the DSC curve of the thermally adhesive resin layer 4 satisfying the above-mentioned conditions (i.e., a melting peak temperature of 160.0°C or higher, no shoulder peak in the temperature range of 100.0°C or higher and 150.0°C or lower, and a shoulder peak at a temperature above 150.0°C), the thermally adhesive resin layer 4 is preferably formed from a resin composition containing random polypropylene, homopolypropylene, and an elastomer. The resin composition may contain block polypropylene, but from the viewpoint of more suitably exhibiting the effects of the third aspect of the present disclosure, it is preferable that the resin composition does not contain block polypropylene.

[0182] The thermally adhesive resin layer 4 may be formed of one type of resin alone or 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.

[0183] From the viewpoint of more suitably exerting the effects of the third aspect of the present disclosure, the content of random polypropylene in the resin composition is preferably about 5% by mass or more, more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and is preferably about 35% by mass or less, more preferably about 30% by mass or less, even more preferably about 20% by mass or less. Preferred ranges include about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, and about 15 to 20% by mass.

[0184] Furthermore, from the viewpoint of more suitably exerting the effects of the third aspect of the present disclosure, the content of homopolypropylene in the resin composition is preferably about 30% by mass or more, more preferably about 35% by mass or more, even more preferably about 40% by mass or more, and is preferably about 70% by mass or less, more preferably about 65% by mass or less, even more preferably about 60% by mass or less. Preferred ranges include about 30 to 70% by mass, about 30 to 65% by mass, about 30 to 60% by mass, about 35 to 70% by mass, about 35 to 65% by mass, about 35 to 60% by mass, about 40 to 70% by mass, about 40 to 65% by mass, and about 40 to 60% by mass.

[0185] From the viewpoint of more suitably exerting the effects of the third aspect of the present disclosure, the content of the elastomer in the resin composition is preferably about 10% by mass or more, more preferably about 15% by mass or more, even more preferably about 20% by mass or more, and is preferably about 50% by mass or less, more preferably about 45% by mass or less, even more preferably about 40% by mass or less. Preferred ranges include about 10 to 50% by mass, about 10 to 45% by mass, about 10 to 40% by mass, about 15 to 50% by mass, about 15 to 45% by mass, about 15 to 40% by mass, about 20 to 50% by mass, about 20 to 45% by mass, and about 20 to 40% by mass.

[0186] In the third aspect of the present disclosure, the term "elastomer" refers to a soft polymer having elasticity like rubber. From the viewpoint of more suitably exhibiting the effects of the third aspect of the present disclosure, the elastomer is preferably a binary copolymer or a tertiary copolymer. The elastomer is also preferably a propylene-based elastomer. Examples of the propylene-based elastomer include binary copolymers and tertiary copolymers. Examples of binary copolymers include propylene-ethylene copolymer elastomers and propylene-butene copolymer elastomers, and examples of tertiary copolymers include propylene-ethylene-butene copolymer elastomers and ethylene-propylene-diene copolymer elastomers. Among the elastomers, a propylene-ethylene copolymer elastomer is preferred as the binary copolymer.

[0187] From the viewpoint of more suitably exerting the effects of the third aspect of the present disclosure, the specific composition of the resin composition may be, for example, a random polypropylene content of about 5% by mass or more (more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and also preferably about 35% by mass or less, more preferably about 30% by mass or less, and even more preferably about 20% by mass or less; preferred ranges include about 5 to 35% by mass, about 5 to 30% by mass, about 5 to 20% by mass, about 10 to 35% by mass, about 10 to 30% by mass, about 10 to 20% by mass, about 15 to 35% by mass, about 15 to 30% by mass, and about 15 to 20% by mass), and a homopolypropylene content of about 30% by mass or more (more preferably about 35% by mass or more, even more preferably about 40% by mass or more, and also preferably about 70% by mass or less, more preferably about 65% by mass). % by mass or less, more preferably about 60% by mass or less, and preferred ranges include about 30 to 70% by mass, about 30 to 65% by mass, about 30 to 60% by mass, about 35 to 70% by mass, about 35 to 65% by mass, about 35 to 60% by mass, about 40 to 70% by mass, about 40 to 65% by mass, and about 40 to 60% by mass, and the elastomer content is about 10% by mass or more (more preferably about 15% by mass or more, and even more preferably The content is at least about 20% by mass, and is preferably not more than about 50% by mass, more preferably not more than about 45% by mass, and even more preferably not more than about 40% by mass, with preferred ranges being about 10 to 50% by mass, about 10 to 45% by mass, about 10 to 40% by mass, about 15 to 50% by mass, about 15 to 45% by mass, about 15 to 40% by mass, about 20 to 50% by mass, about 20 to 45% by mass, about 20 to 40% by mass, etc.) The resin composition is also preferably formed from a resin composition containing only random polypropylene, homopolypropylene, and elastomer as the resin (excluding additives such as lubricants described below).

[0188] In the present disclosure, when the thermally adhesive resin layer 4 is laminated with the barrier layer 3, the adhesive layer 5, or the like to produce the exterior packaging material 10 for an electricity storage device of the present disclosure, a pre-formed resin film may be used as the thermally adhesive resin layer 4. Alternatively, the thermally adhesive resin that forms the thermally adhesive resin layer 4 may be formed into a film on the surface of the barrier layer 3, the adhesive layer 5, or the like by extrusion molding, coating, or the like, to form the thermally adhesive resin layer 4 from a resin film.

[0189] In the present disclosure, the thermally adhesive resin layer 4 may contain a lubricant or the like as necessary. When the thermally adhesive resin layer 4 contains a lubricant, the formability of the electrical storage device packaging material can be improved. The lubricant is not particularly limited, and known lubricants can be used.

[0190] The lubricant is not particularly limited, but preferably an amide-based lubricant is used. 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 a combination of two or more types is preferred.

[0191] In the present disclosure, from the viewpoint of improving the formability of the exterior material for an electrical storage device, it is preferable that a lubricant be present on at least one of the surface and the interior of the heat-sealable resin layer 4. The lubricant is not particularly limited, but preferably an amide-based lubricant is used. Specific examples of amide-based lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, 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 amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. Specific examples of methylolamides include methylol stearic acid amide. 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 adipamide, 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 adipamide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamidoethyl 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.

[0192] In the present disclosure, when a lubricant is present on the surface of the heat-sealable resin layer 4, the amount of the lubricant present is not particularly limited. However, from the viewpoint of improving the formability of the exterior material for an electricity storage device, the amount of the lubricant present is preferably about 1 mg / m 2 or more, more preferably about 3 mg / m 2 or more, more preferably about 5 mg / m 2 or more, more preferably about 10 mg / m 2 or more, 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

[0193] In the present disclosure, when a lubricant is present inside the heat-sealable resin layer 4, the amount thereof is not particularly limited, but from the viewpoint of improving the formability of the packaging 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 present is not particularly limited, but from the viewpoint of improving the formability of the exterior material for an electrical 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 present 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.

[0194] In the present disclosure, the lubricant present on the surface of the heat-sealable resin layer 4 may be a lubricant exuded from the resin constituting the heat-sealable resin layer 4, or a lubricant applied to the surface of the heat-sealable resin layer 4.

[0195] In the present disclosure, the thickness of the heat-sealable resin layer 4 is not particularly limited as long as it functions to heat-seal the heat-sealable resin layers to each other and seal the electricity storage device element, but may be, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. Note that, for example, when the thickness of the adhesive layer 5 described below is 10 μm or more, the thickness of the heat-sealable resin layer 4 is preferably about 85 μm or less, more preferably about 15 to 45 μm. For example, when the thickness of the adhesive layer 5 described below is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the heat-sealable resin layer 4 is preferably about 20 μm or more, more preferably about 35 to 85 μm.

[0196] [Adhesive Layer 5] In the packaging material for an electricity storage device according to the present disclosure, the adhesive layer 5 is a layer that is provided as needed between the barrier layer 3 (or the corrosion-resistant coating) and the heat-sealable resin layer 4 in order to firmly bond them together.

[0197] The adhesive layer 5 is formed of a resin capable of bonding the barrier layer 3 and the heat-sealable 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.

[0198] Furthermore, from the viewpoint of firmly bonding 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 polyolefins, acid-modified polyolefins, cyclic polyolefins, and acid-modified cyclic polyolefins exemplified for the heat-sealable resin layer 4 described above. On the other hand, from the viewpoint of firmly bonding the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 preferably contains an acid-modified polyolefin. Examples of acid-modified components include dicarboxylic acids such as maleic acid, itaconic acid, succinic acid, and adipic acid, as well as anhydrides thereof, acrylic acid, and methacrylic acid. However, from the viewpoint of ease of modification and versatility, maleic anhydride is most preferred. From the viewpoint of the heat resistance of the electrical storage device exterior material, the olefin component is preferably a polypropylene-based resin, and the adhesive layer 5 most preferably contains maleic anhydride-modified polypropylene.

[0199] 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 an acid-modified polyolefin as a main component, and even more preferably an acid-modified polypropylene as a main component. Here, "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, when the adhesive layer 5 contains acid-modified polypropylene as a main component, it means that the content of 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.

[0200] The presence of a polyolefin skeleton in the resin constituting the adhesive layer 5 can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like, and the analysis method is not particularly limited. Furthermore, the presence of an acid-modified polyolefin in the resin constituting the adhesive layer 5 can be determined by, for example, measuring a maleic anhydride-modified polyolefin by infrared spectroscopy, and finding a wave number of 1760 cm -1 Nearby and wave number 1780 cm -1 A peak derived from maleic anhydride is detected around this point. However, if the degree of acid modification is low, the peak may be small and not be detected. In this case, analysis can be performed using nuclear magnetic resonance spectroscopy.

[0201] Furthermore, from the viewpoint of ensuring durability such as heat resistance and resistance to contents of the electrical storage device packaging material, and of ensuring 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 described above.

[0202] 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. 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 is particularly preferred. The adhesive layer 5 preferably contains at least one selected from the group consisting of polyurethane, polyester, and epoxy resin, and more preferably contains polyurethane and epoxy resin. Examples of polyesters include ester resins formed by the reaction of epoxy groups with maleic anhydride groups, and amide ester resins formed by the reaction of oxazoline groups with maleic anhydride groups. If unreacted curing agents such as compounds having an isocyanate group, compounds having an oxazoline group, or epoxy resins remain in the adhesive layer 5, the presence of the unreacted materials can be confirmed by a method selected from the group consisting of infrared spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and the like.

[0203] Furthermore, from the viewpoint of further enhancing 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 C—O—C bond. Examples of curing agents having a heterocycle include curing agents having an oxazoline group and curing agents having an epoxy group. Examples of curing agents having a C═N bond include curing agents having an oxazoline group and curing agents having an isocyanate group. Examples of curing agents having a C—O—C bond include curing agents having an oxazoline group and curing agents having an epoxy group. Whether the adhesive layer 5 is a cured product of a resin composition containing such a curing agent 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.

[0204] 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 curing agents include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymers or nurates thereof, mixtures of these, and copolymers with other polymers. Other examples include adducts, biurets, and isocyanurates.

[0205] 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 %, of 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.

[0206] 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. Examples of commercially available products include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

[0207] 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.

[0208] Examples of compounds having epoxy groups include epoxy resins. The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure by the epoxy groups present in the molecule, and known epoxy resins can be used. The weight-average molecular weight of the epoxy resin is preferably about 50 to 2,000, more preferably about 100 to 1,000, 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.

[0209] 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.

[0210] The proportion 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 %, of 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.

[0211] 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 two-component curing polyurethane.

[0212] 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 %, of 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.

[0213] 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 the 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.

[0214] The adhesive layer 5 may contain a modifier having a carbodiimide group.

[0215] From the viewpoint of more suitably exerting the effects of the present disclosure, the adhesive layer 5 is preferably formed from a resin composition containing an acid-modified polypropylene and an elastomer, and further containing at least one of block polypropylene and homopolypropylene. The resin composition may further contain random polypropylene, polyethylene, etc. Note that, from the viewpoint of improving adhesion to the barrier layer 3 and heat resistance, the adhesive layer 5 is preferably an acid-modified homopolypropylene (i.e., acid-modified homopolypropylene).

[0216] From the viewpoint of more suitably exerting the effects of the present disclosure, the content of acid-modified polypropylene in the resin composition forming the adhesive layer 5 is preferably about 5% by mass or more, more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and is preferably about 90% by mass or less, more preferably about 80% by mass or less, even more preferably about 70% by mass or less. Preferred ranges include about 5 to 90% by mass, about 5 to 80% by mass, about 5 to 70% by mass, about 10 to 90% by mass, about 10 to 80% by mass, about 10 to 70% by mass, about 15 to 90% by mass, about 15 to 80% by mass, and about 15 to 70% by mass.

[0217] From the viewpoint of more suitably exerting the effects of the present disclosure, the elastomer content in the resin composition forming the adhesive layer 5 is preferably about 25% by mass or more, more preferably about 30% by mass or more, even more preferably about 35% by mass or more, and is preferably about 60% by mass or less, more preferably about 55% by mass or less, even more preferably about 50% by mass or less. Preferred ranges include about 25 to 60% by mass, about 25 to 55% by mass, about 25 to 50% by mass, about 30 to 60% by mass, about 30 to 55% by mass, about 30 to 50% by mass, about 35 to 60% by mass, about 35 to 55% by mass, and 35 to 50% by mass.

[0218] From the viewpoint of more suitably exerting the effects of the present disclosure, the elastomer contained in the resin composition forming the adhesive layer 5 is preferably a binary copolymer or a tertiary copolymer. The elastomer is preferably a propylene-based elastomer. Examples of the propylene-based elastomer include binary copolymers and tertiary copolymers. Examples of the binary copolymer include a propylene-ethylene copolymer elastomer and a propylene-butene copolymer elastomer, and examples of the tertiary copolymer include a propylene-ethylene-butene copolymer elastomer and an ethylene-propylene-diene copolymer elastomer. Among the elastomers, a propylene-ethylene copolymer elastomer is preferred as the binary copolymer, and a propylene-ethylene-butene copolymer elastomer is preferred as the tertiary copolymer.

[0219] From the viewpoint of more suitably exerting the effects of the present disclosure, the content of block polypropylene in the resin composition forming adhesive layer 5 is preferably about 30% by mass or more, more preferably about 35% by mass or more, even more preferably about 40% by mass or more, and is preferably about 95% by mass or less, more preferably about 90% by mass or less, and even more preferably about 85% by mass or less. Preferred ranges include about 30 to 95% by mass, about 30 to 90% by mass, about 30 to 85% by mass, about 35 to 95% by mass, about 35 to 90% by mass, about 35 to 85% by mass, about 40 to 95% by mass, about 40 to 90% by mass, and about 40 to 85% by mass.

[0220] Furthermore, from the viewpoint of more suitably exerting the effects of the present disclosure, the content of homopolypropylene in the resin composition forming the adhesive layer 5 is preferably about 20% by mass or more, more preferably about 25% by mass or more, even more preferably about 30% by mass or more, and is preferably about 80% by mass or less, more preferably about 75% by mass or less, even more preferably about 70% by mass or less. Preferred ranges include about 20 to 80% by mass, about 20 to 75% by mass, about 20 to 70% by mass, about 25 to 80% by mass, about 25 to 75% by mass, about 25 to 70% by mass, about 30 to 80% by mass, about 30 to 75% by mass, and about 30 to 70% by mass.

[0221] From the viewpoint of more suitably exerting the effects of the present disclosure, the content of random polypropylene in the resin composition forming the adhesive layer 5 is preferably about 0% by mass or more, more preferably about 1% by mass or more, even more preferably about 2% by mass or more, and is preferably about 30% by mass or less, more preferably about 25% by mass or less, and even more preferably about 20% by mass or less. Preferred ranges include about 0 to 30% by mass, about 0 to 25% by mass, about 0 to 20% by mass, about 1 to 30% by mass, about 1 to 25% by mass, about 1 to 20% by mass, about 2 to 30% by mass, about 2 to 25% by mass, and about 2 to 20% by mass.

[0222] From the viewpoint of more suitably exerting the effects of the present disclosure, the polyethylene content in the resin composition forming the adhesive layer 5 is, for example, about 0% by mass or more, preferably about 1% by mass or more, more preferably about 2% by mass or more, and even more preferably about 3% by mass or more, and is preferably about 30% by mass or less, more preferably about 25% by mass or less, and even more preferably about 20% by mass or less. Preferred ranges include about 0 to 30% by mass, about 0 to 25% by mass, about 0 to 20% by mass, about 1 to 30% by mass, about 1 to 25% by mass, about 1 to 20% by mass, about 2 to 30% by mass, about 2 to 25% by mass, about 2 to 20% by mass, about 3 to 30% by mass, about 3 to 25% by mass, and about 3 to 20% by mass.

[0223] From the viewpoint of more suitably exerting the effects of the present disclosure, the specific composition of the resin composition may be, for example, an acid-modified polypropylene content of about 5% by mass or more (more preferably about 10% by mass or more, even more preferably about 15% by mass or more, and also preferably about 90% by mass or less, more preferably about 80% by mass or less, even more preferably about 70% by mass or less; preferred ranges include about 5 to 90% by mass, about 5 to 80% by mass, about 5 to 70% by mass, about 10 to 90% by mass, about 10 to 80% by mass, about 10 to 70% by mass, about 15 to 90% by mass, about 15 to 80% by mass, about 15 to 70% by mass, etc.), and an elastomer content of about 25% by mass or more (more preferably about 30% by mass). or more, more preferably about 35% by mass or more, and preferably about 60% by mass or less, more preferably about 55% by mass or less, and even more preferably about 50% by mass or less. Preferred ranges include about 25 to 60% by mass, about 25 to 55% by mass, about 25 to 50% by mass, about 30 to 60% by mass, about 30 to 55% by mass, about 30 to 50% by mass, about 35 to 60% by mass, about 35 to 55% by mass, about 35 to 50% by mass, etc.), and the block polypropylene content is about 30% by mass or more (more preferably about 35% by mass or more, even more preferably about 40% by mass or more, and preferably about 95% by mass or less, more preferably about 90% by mass or less, and even more preferably about 85% by mass or less).Preferred ranges include about 30 to 95% by mass, about 30 to 90% by mass, about 30 to 85% by mass, about 35 to 95% by mass, about 35 to 90% by mass, about 35 to 85% by mass, about 40 to 95% by mass, about 40 to 90% by mass, and about 40 to 85% by mass, and the homopolypropylene content is about 20% by mass or more (more preferably about 25% by mass or more, even more preferably about 30% by mass or more, and also preferably about 80% by mass or less, more preferably about 75% by mass). The content of random polypropylene is about 0% by mass or more (more preferably about 1% by mass or more, and even more preferably about 2% by mass or less), and preferably about 70% by mass or less, and preferred ranges include about 20 to 80% by mass, about 20 to 75% by mass, about 20 to 70% by mass, about 25 to 80% by mass, about 25 to 75% by mass, about 25 to 70% by mass, about 30 to 80% by mass, about 30 to 75% by mass, and about 30 to 70% by mass). It is about 30% by mass or less, more preferably about 25% by mass or less, and even more preferably about 20% by mass or less. Preferred ranges include about 0 to 30% by mass, about 0 to 25% by mass, about 0 to 20% by mass, about 1 to 30% by mass, about 1 to 25% by mass, about 1 to 20% by mass, about 2 to 30% by mass, about 2 to 25% by mass, and about 2 to 20% by mass. The polyethylene content is, for example, about 0% by mass or more (preferably about 1% by mass or more, more preferably about 2% by mass or more, and even more preferably about 20% by mass or less). It is preferably about 3% by mass or more, and preferably about 30% by mass or less, more preferably about 25% by mass or less, and even more preferably about 20% by mass or less, with preferred ranges being about 0 to 30% by mass, about 0 to 25% by mass, about 0 to 20% by mass, about 1 to 30% by mass, about 1 to 25% by mass, about 1 to 20% by mass, about 2 to 30% by mass, about 2 to 25% by mass, about 2 to 20% by mass, about 3 to 30% by mass, about 3 to 25% by mass, about 3 to 20% by mass, etc. The resin composition is also preferably formed from a resin composition containing an acid-modified polypropylene and an elastomer as a resin (excluding additives such as a lubricant, which will be described later), and further containing only at least one of block polypropylene and homopolypropylene.

[0224] When the adhesive layer 5 is laminated with the barrier layer 3, the heat-sealable resin layer 4, or the like to produce the packaging material for an electricity storage device 10 of the present disclosure, a pre-formed resin film may be used as the adhesive layer 5. Alternatively, 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.

[0225] 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 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 adhesives such as those exemplified for 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. Furthermore, 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 heat-fusible resin layer 4 and the adhesive layer 5 can be formed, for example, by extrusion molding.

[0226] [Surface Coating Layer 6] The packaging material for an electricity storage device according to the present disclosure may, if necessary, have a surface coating layer 6 on the substrate layer 1 (the side of the substrate layer 1 opposite to the barrier layer 3) 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 packaging material for an electricity storage device when an electricity storage device is assembled using the packaging material for an electricity storage device.

[0227] 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 phenolic resin, or a modified version of these resins. It may also be a copolymer of these resins or a modified version of the copolymer. It may also 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.

[0228] When the resin forming the surface coating layer 6 is a curable resin, the resin may be either a one-component curable resin or a two-component curable resin, but is preferably a two-component curable resin. 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.

[0229] Examples of two-component curing polyurethanes include polyurethanes containing a first component containing a polyol compound and a second component containing an isocyanate compound. Preferred examples of two-component curing polyurethanes include those containing a polyol, such as polyester polyol, polyether polyol, or acrylic polyol, as the first component and an aromatic or aliphatic polyisocyanate as the second component. Examples of polyurethanes include polyurethanes containing an isocyanate compound and a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance. Examples of polyurethanes include polyurethanes containing a polyol compound and a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance. Examples of polyurethanes include polyurethanes obtained by reacting a polyol compound with an isocyanate compound in advance and then curing the polyurethane compound with moisture, such as in the air. Polyol compounds preferably include polyester polyols having hydroxyl groups on the side chains in addition to the terminal hydroxyl groups of the repeating units. Examples of second components 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). Also included are polyfunctional isocyanate-modified compounds of one or more of these diisocyanates. Furthermore, polymers (e.g., trimers) can also be used as polyisocyanate compounds. Examples of such polymers include adducts, biurets, and nurates. It should be noted that an aliphatic isocyanate compound refers to an isocyanate that has an aliphatic group but does not have an aromatic ring, an alicyclic isocyanate compound refers to an isocyanate that has an alicyclic hydrocarbon group, and an aromatic isocyanate compound refers to an isocyanate that has an aromatic ring.The surface coating layer 6 is formed from polyurethane, which provides the electrical storage device packaging material with excellent electrolyte resistance.

[0230] The surface coating layer 6 may contain additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, antistatic agents, and pigments, as necessary, in at least one of the surface and interior of the surface coating layer 6, depending on the functionality to be provided to the surface of the surface coating layer 6. Examples of additives include fine particles with an average particle size of approximately 0.5 nm to 5 μm. The average particle size of the additive is the median size measured with a laser diffraction / scattering particle size distribution analyzer.

[0231] The additive may be either inorganic or organic. The shape of the additive is not particularly limited, and examples thereof include spherical, fibrous, plate-like, amorphous, and scaly shapes.

[0232] 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, cross-linked acrylic, cross-linked styrene, cross-linked polyethylene, benzoguanamine, gold, aluminum, copper, and nickel. The additives may be used alone or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferred from the viewpoints of dispersion stability and cost. Furthermore, mica is preferred from the viewpoint of heat dissipation from the power storage device. The additives may also be subjected to various surface treatments, such as insulation treatment and high-dispersibility treatment.

[0233] The method for forming the surface coating layer 6 is not particularly limited, and examples thereof include a method of applying a resin to form 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.

[0234] In the present disclosure, from the viewpoint of improving the formability of the exterior material for an electrical storage device, it is preferable that a lubricant be present on at least one of the surface and the interior of the surface coating layer 6. The lubricant is not particularly limited, but preferably an amide-based lubricant is used. Specific examples of amide-based lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, 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 amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. Specific examples of methylolamides include methylol stearic acid amide. 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 adipamide, 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 adipamide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamidoethyl 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.

[0235] 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 Above, 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 or less, preferably 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

[0236] The lubricant present on the surface of the surface coating layer 6 may be a lubricant exuded from the resin that constitutes the surface coating layer 6, or a lubricant applied to the surface of the surface coating layer 6.

[0237] The surface coating layer 6 contains a colorant, which allows the electrical storage device exterior material to be colored. 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.

[0238] 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 finely powdered mica and fish scale foil.

[0239] Among colorants, carbon black is preferred for making the exterior material for an electricity storage device black, and mica is preferred from the viewpoint of dissipating heat generated from the electricity storage device.

[0240] 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 with a laser diffraction / scattering particle size distribution analyzer.

[0241] The content of the colorant in the surface coating layer 6 is not particularly limited as long as the packaging 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 %.

[0242] 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.

[0243] 3. Manufacturing Method of Sheathing Material for Electricity Storage Device The manufacturing method of the sheathing material for an electricity storage device is not particularly limited, as long as a laminate can be obtained in which the layers included in the sheathing material for an electricity storage device of the present disclosure are stacked. For the first aspect of the present disclosure, an example method includes a step of stacking at least the barrier layer 3 and the heat-sealable resin layer 4 in this order. As described above, in the sheathing material for an electricity storage device of the first aspect of the present disclosure, the heat-sealable resin layer 4 has a logarithmic decrement ΔE at 150°C in rigid pendulum measurement of 0.075 or less. For the second aspect of the present disclosure, an example method includes a step of stacking at least the barrier layer 3 and the heat-sealable resin layer 4 in this order.

[0023] As described above, in the electrical storage device packaging material of the second aspect of the present disclosure, a sea-island structure is observed in a cross-sectional image of the thermally adhesive resin layer 4 taken using a field emission scanning electron microscope, in a cross section of the thermally adhesive resin layer in a direction parallel to the TD and in the thickness direction, and when the cross-sectional image is observed at a magnification of 20,000 times over an area of ​​4.50 μm × 6.37 μm, the number of island portions having a maximum diameter of 100 nm or more and less than 300 nm is 10 or less, and no island portion having a maximum diameter of 300 nm or more is included, and when the cross-sectional image is observed at a magnification of 50,000 times over, lamellae are observed in the island portions.

[0024] Furthermore, with regard to the third aspect of the present disclosure, a method can be mentioned which includes a step of laminating at least a barrier layer 3 and a thermally adhesive resin layer 4 in this order. As described above, in the exterior packaging material for an electricity storage device according to the third aspect of the present disclosure, the heat-fusible resin layer 4 has a melting peak temperature of 160.0°C or higher in a DSC curve obtained by differential scanning calorimetry, no shoulder peak is present in the temperature range of 100.0°C or higher and 150.0°C or lower, and a shoulder peak is present at a temperature above 150.0°C.

[0244] An example of a manufacturing method for 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 to form 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 the base layer 1 is laminated thereon, and the adhesive layer 2 is cured.

[0245] Next, a heat-sealable resin layer 4 is laminated on the barrier layer 3 of the laminate A. When the heat-sealable resin layer 4 is laminated directly 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 thermal lamination or extrusion lamination. 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 by, for example, (1) extrusion lamination, (2) thermal lamination, (3) sandwich lamination, or (4) dry lamination. Examples of the (1) extrusion lamination method include a method of laminating the adhesive layer 5 and the heat-sealable resin layer 4 on the barrier layer 3 of the laminate A by extrusion (co-extrusion lamination, tandem lamination), etc. Examples of the (2) thermal lamination method include a method of separately forming a laminate in which an adhesive layer 5 and a heat-fusible resin layer 4 are laminated, and laminating this 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 this on the heat-fusible resin layer 4. Examples of the (3) sandwich lamination method include a method of pouring a molten adhesive layer 5 between the barrier layer 3 of the laminate A and the heat-fusible resin layer 4 that has been previously formed into a sheet, and bonding the laminate A and the heat-fusible resin layer 4 together via the adhesive layer 5. Examples of the (4) dry lamination method include a method of solution-coating an adhesive for forming the adhesive layer 5 on the barrier layer 3 of the laminate A, drying the adhesive, or baking the adhesive, and laminating the heat-fusible resin layer 4 that has been previously formed into a sheet on the adhesive layer 5.

[0246] 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 the surface coating layer 6 is formed 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.

[0247] As described above, a laminate is formed which includes the optional surface coating layer 6 / substrate layer 1 / optional adhesive layer 2 / barrier layer 3 / optional adhesive layer 5 / thermally adhesive resin layer 4 in this order, and in order to strengthen the adhesion of the optional adhesive layer 2 and adhesive layer 5, the laminate may be further subjected to a heat treatment.

[0248] In the 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 processability. For example, by subjecting the surface of the base layer 1 opposite to the barrier layer 3 to corona treatment, the printability of ink on the surface of the base layer 1 can be improved.

[0249] 4. Uses of the Electricity Storage Device Exterior Material The electricity storage device exterior material of the present disclosure is used in a package for hermetically housing electricity storage device elements 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 including at least a positive electrode, a negative electrode, and an electrolyte in a package formed from the electricity storage device exterior material of the present disclosure. In other words, an electricity storage device can be formed by wrapping an electricity storage device element in the electricity storage device exterior material of the present disclosure.

[0250] Specifically, an electricity storage device using the electricity storage device packaging material is provided by covering an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte with the electricity storage device packaging material of the present disclosure in a state in which metal terminals connected to each of the positive electrode and the negative electrode protrude outward, so that a flange portion (a region where the heat-sealable resin layers contact each other) can be formed around the periphery of the electricity storage device element, and then heat-sealing the heat-sealable resin layers of the flange portion to form a hermetic seal. Note that when an electricity storage device element is housed in a package formed from the electricity storage device packaging material of the present disclosure, the package is formed so that the heat-sealable resin portion of the electricity storage device packaging material of the present disclosure faces inside (the surface that contacts the electricity storage device element). A package may be formed by overlapping two electrical storage device exterior materials with the heat-sealable resin layers facing each other and heat-sealing the peripheral edges of the overlapped electrical storage device exterior materials, or by folding one electrical storage device exterior material over and overlapping the materials and heat-sealing the peripheral edges, as in the example shown in Fig. 5. When the materials are folded over and overlapped, the package may be formed by heat-sealing the sides other than the folded side to form a three-sided seal, as in the example shown in Fig. 5, or by folding over the material so as to form a flange and seal all four sides. When the innermost and outermost layers 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.

[0251] The electricity storage device element may be sealed with a lid in addition to the electricity storage device exterior material. That is, the electricity storage device exterior material and the lid constitute an exterior (an exterior for an electricity storage device) that seals the electricity storage device element. For example, the electricity storage device element may be housed inside a cylindrically configured electricity storage device exterior material, and the opening may be closed with the lid. In another example, the electricity storage device element connected to the lid may be housed inside a cylindrically configured electricity storage device exterior material that has an opening, and the opening may be closed with the lid. The lid and the electricity storage device exterior material are preferably joined by any means. From the viewpoint of reducing dead space between the electricity storage device element and the electricity storage device exterior material to improve the volumetric energy density of the electricity storage device, the electricity storage device exterior material is preferably wrapped around the electricity storage device element and the lid.

[0252] 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 this disclosure, when the lid body is referred to as a resin molded product, this does not include an embodiment in which the lid body is formed solely from a film specified by JIS K6900-1994 [Plastics - Terminology] JIS (Japanese Industrial Standards) [Packaging Terminology] standard. When the lid body is a metal molded product, the lid body also functions as a metal terminal, so the metal terminal can be omitted. The lid body may be formed from a resin material and a conductive material.

[0253] Furthermore, a recess for accommodating an electricity storage device element may be formed in the electricity storage device packaging material by deep drawing or bulging molding. As shown in the example in Fig. 5, a recess may be provided in one electricity storage device packaging material and no recess may be provided in the other electricity storage device packaging material, or a recess may also be provided in the other electricity storage device packaging material.

[0254] The exterior material for an electricity storage device of the present disclosure can be suitably used in an electricity storage device such as a battery (including a condenser, a capacitor, etc.). The exterior material for an electricity storage device of the present disclosure may be used in either a primary battery or a secondary battery, but is preferably used in a secondary battery. The type of secondary battery to which the exterior material for an electricity storage device of the present disclosure is applied is not particularly limited, and examples include lithium ion batteries, lithium ion polymer batteries, all-solid-state batteries, semi-solid batteries, quasi-solid batteries, polymer batteries, all-resin batteries, lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are suitable applications for the exterior material for an electricity storage device of the present disclosure.

[0255] The present disclosure will be described in detail below with reference to examples and comparative examples, but the present disclosure is not limited to the examples.

[0256] <Production of the first embodiment of the exterior material for an electricity storage device> Example 1A A laminate was prepared as a base layer, in which a biaxially oriented polyethylene terephthalate (PET) film (thickness 12 μm) and an oriented nylon (ONy) film (thickness 15 μm) were bonded together with an adhesive layer (formed with a two-component curing urethane adhesive, with a thickness of 3 μm after curing). Furthermore, an aluminum foil (JIS H4160:1994 A8021H-O (thickness 40 μm)) was prepared as a barrier layer. Both sides of the aluminum foil were subjected to a chemical conversion treatment. The chemical conversion treatment of the aluminum foil was carried out by applying a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid to a coating amount of chromium of 10 mg / m. 2 (dry mass) was applied to both sides of an aluminum foil by roll coating, and baked.

[0257] Next, a two-component curing urethane adhesive was used to bond the base material layer and the barrier layer together with an adhesive layer (thickness: 3 μm) by a dry lamination method, thereby producing a laminate in which the base material layer / adhesive layer / barrier layer were laminated in this order.

[0258] Next, on the barrier layer of each of the laminates obtained above, a resin composition forming an adhesive layer (40 μm thick) (a resin composition consisting of maleic anhydride-modified homopolypropylene, homopolypropylene, and a propylene-ethylene-butene copolymer elastomer (terpolymer)) and a resin composition forming a heat-sealable resin layer (40 μm thick) (a resin composition consisting of random polypropylene, homopolypropylene, and a propylene-ethylene copolymer elastomer (binary copolymer)) were co-extruded, thereby laminating the adhesive layer / heat-sealable resin layer on the barrier layer. Next, the obtained laminate was aged and heated to obtain an exterior packaging material for an electricity 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.

[0259] Example 2A An exterior material for an electricity storage device comprising a laminate in which a base layer / adhesive layer / barrier layer / adhesive layer / thermally fusible resin layer were laminated in this order was obtained in the same manner as in Example 1A, except that a resin composition comprising maleic anhydride-modified homopolypropylene, homopolypropylene, and a propylene-ethylene copolymer elastomer (binary copolymer) was used as the resin composition forming the adhesive layer (thickness 40 μm).

[0260] Example 3A An exterior material for a storage battery device consisting of a laminate in which a base layer / adhesive layer / barrier layer / adhesive layer / thermal adhesive resin layer were laminated in this order was obtained in the same manner as in Example 1A, except that a resin composition consisting of maleic anhydride-modified homopolypropylene, block polypropylene, and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin composition forming the adhesive layer (thickness 40 μm), and a resin composition consisting of block polypropylene and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin composition forming the heat-sealable resin layer (thickness 40 μm).

[0261] Example 4A An exterior material for an electricity storage device comprising a laminate in which a base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order was obtained in the same manner as in Example 1A, except that a resin composition comprising random polypropylene, homopolypropylene, and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin composition forming the heat-sealable resin layer (thickness 40 μm).

[0262] In Examples 1A to 4A, when the thickness of the barrier layer was increased from 40 μm to 60 μm and further to 80 μm, the seal strength in an environment of 25° C. and the seal strength in an environment of 150° C. increased, the electrolyte resistance was excellent, and whitening did not occur during molding. This result shows that the thickness of the barrier layer is not limited to 40 μm and may be increased, for example, to 80 μm.

[0263] Comparative Example 1A An exterior material for a storage battery device was obtained in the same manner as in Example 1A, except that maleic anhydride-modified homopolypropylene was used as the resin forming the adhesive layer (thickness 40 μm), and a resin composition composed of random polypropylene, polyethylene, and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin forming the heat-sealable resin layer (thickness 40 μm). The exterior material was a laminate in which the base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0264] Comparative Example 2A An exterior material for a storage battery device was obtained in the same manner as in Example 1A, except that maleic anhydride-modified homopolypropylene was used as the resin forming the adhesive layer (thickness 40 μm), and a resin composition composed of random polypropylene, block polypropylene, and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin composition forming the heat-sealable resin layer (thickness 40 μm). The exterior material was a laminate in which a base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0265] <Measurement of Logarithmic Decay Rate ΔE by Rigid Pendulum Measurement> A schematic diagram illustrating the method for measuring the logarithmic decay rate ΔE by rigid pendulum measurement is shown in Figure 6. A rigid pendulum-type physical property tester (model number: RPT-3000W, manufactured by A&D Co., Ltd.) was used, with FRB-100 used for the frame of the pendulum 30, RBP-020 used for the cylindrical cylinder edge 30a of the edge portion, and CHB-100 used for the cooling block 31, and the initial amplitude was approximately 0.3 degrees. The pendulum adsorption time was 1.0 seconds, and the measurement interval was 10 seconds. The exterior material for an electricity storage device was cut to 45 mm in MD and 15 mm in TD to prepare a test sample. Furthermore, a vibration displacement detector 32 was used.

[0266] The cylindrical cylinder edge RBP-020 used in this measurement has a small diameter of 2 mm, and is easily sunk from the surface to the interior of the heat-sealable resin layer during measurement, making it suitable for evaluating the properties of the heat-sealable resin layer as a whole. For this reason, this measurement is suitable from the perspective of evaluating the correlation with the seal strength in a high-temperature environment (150°C environment) described below.

[0267] The test sample was placed on a cooling block 31 with the measurement surface (thermal adhesive resin layer) facing upward, and the cylindrical cylinder edge 30a with a pendulum was placed on the measurement surface so that its axial direction was perpendicular to the MD direction of the test sample. To prevent the test sample from lifting or warping during measurement, tape was attached to a location on the cooling block 31 that would not affect the measurement results. The cylindrical cylinder edge 30a was brought into contact with the surface of the thermal adhesive resin layer. Next, the logarithmic decrement ΔE of the thermal adhesive resin layer was measured using the cooling block 31 at a temperature increase rate of 3°C / min over a temperature range from 0°C to 180°C (N=1). The logarithmic decrement ΔE was measured when the surface temperature of the thermal adhesive resin layer of the test sample (exterior material for an electricity storage device) reached 150°C. The results are shown in Table 1A. A logarithmic decay factor ΔE at 150°C of 0.075 or less was used in this measurement as an index for achieving a heat-resistant seal strength of 25 N / 15 mm or more at 150°C (described later). The logarithmic decay factor ΔE was calculated using the following formula. The value was rounded to the nearest tenth to calculate the third decimal place. ΔE = [ln(A1 / A2) + ln(A2 / A3) + . . . + ln(An / An+1)] / n, where A is amplitude and n is wave number.

[0268] In Examples 1A to 4A, the logarithmic decrement ΔE of the heat-sealable resin layer in an 80°C environment was all greater than 0.02. The logarithmic decrement ΔE of the heat-sealable resin layer in an 80°C environment was a value measured in the same manner as the logarithmic decrement ΔE of the heat-sealable resin layer in a 150°C environment in the method described in <Measurement of logarithmic decrement ΔE by rigid pendulum measurement> above, except that "the logarithmic decrement ΔE when the surface temperature of the heat-sealable resin layer of the test sample (exterior material for an electricity storage device) is used when the surface temperature is 80°C" is replaced with "the logarithmic decrement ΔE when the surface temperature of the heat-sealable resin layer of the test sample (exterior material for an electricity storage device) is used."

[0269] <Evaluation of Crystallinity by FT-IR> The exterior material for an electricity storage device was cut into a 30 mm × 30 mm square to prepare a sample. The surface of the thermal adhesive resin layer of the obtained sample was subjected to infrared absorption spectrum measurement under an environment of a temperature of 25°C and a relative humidity of 50% using an ATR measurement mode of FT / IR6100 manufactured by JASCO Corporation. From the obtained absorption spectrum, a 973 cm -1 The peak intensity P1 near 998 cm originating from the crystalline component -1 The absorption peak intensity P1 near 998 cm originating from the crystalline component -1 The absorption peak intensity P2 near the absorption peak intensity P1 was measured, and the intensity ratio X = P2 / P1 of the absorption peak intensity P2 to the absorption peak intensity P1 was calculated. Here, the infrared absorption spectrum was measured using absorbance values. At this time, the values ​​were calculated to the third decimal place by rounding off the fourth decimal place. The results are shown in Table 1A. Method: Macro ATR method Wavenumber resolution: 4 cm -1 Number of integrations: 32 times Detector: TGS detector ATR prism: Diamond Baseline: Wavenumber 927 cm -1 From 1067 cm -1 Absorption peak intensity P1: Wave number 973 cm -1 Absorption peak intensity P2: wave number 998 cm -1 The peak intensity in the vicinity minus the baseline value

[0270] For example, X-ray diffraction (XRD) has a detection depth of several tens of micrometers, and evaluates the crystallinity of not only the heat-sealable resin layer but also the adhesive layer. In contrast, the FT-IR ATR method has a detection depth of several micrometers, and reflects the crystallinity of only the heat-sealable resin layer. Therefore, the FT-IR ATR method can reflect the crystallinity of the heat-sealable resin layer, which is affected by the electrolyte.

[0271] <Cross-sectional observation of heat-sealable resin layer> An electrical storage device casing material was embedded in a thermosetting epoxy resin and cured. A cross-section was prepared using a commercially available rotary microtome (LEICA EM UC6), and the heat-sealable resin layer of the electrical storage device casing material, along with the embedded resin, was stained with ruthenium tetroxide for 3 hours. After cutting the cross-section 1 μm deep using the microtome, stained sections with thicknesses of 70 nm to 100 nm were obtained using a diamond knife. Cross-sectional images of the stained sections were obtained using a field emission scanning electron microscope (Hitachi High-Technologies Corporation S-4800). The measurement conditions were an acceleration voltage of 30 kV, an emission current of 10 μA, a transmission detector, and no tilt (0°). The sea-island structure was observed at a magnification of 20,000x, and the lamellar structure was observed at a magnification of 50,000x. For the cross-sectional image of the sea-island structure of the heat-fusible resin layer, a 4.50 μm × 6.37 μm area was randomly selected from a 13.5 μm × 19.1 μm area in the central portion of the heat-fusible resin layer at a magnification of 20,000 times to confirm the number of islands contained in the 4.50 μm × 6.37 μm area. Furthermore, the island areas observed at a magnification of 20,000 times were further enlarged to 50,000 times to observe whether or not the islands contained lamellae and whether or not the islands contained a layer with a thickness of 10 nm or more at the boundary between the island and sea portions. The results are shown in Table 1A.

[0272] <Measurement of Seal Strength at 25°C or 150°C> In accordance with the provisions of JIS K7127:1999, the seal strength of the electrical storage device exterior material was measured at each measurement temperature of a 25°C environment and a 150°C environment as follows. Test pieces were prepared by cutting the electrical storage device exterior material into strips with a width of 15 mm in the TD direction. Specifically, as shown in FIG. 7, each electrical storage device exterior material was first cut into 75 mm (TD direction) x 150 mm (MD direction) (FIG. 7a). Next, the electrical storage device exterior material was folded in half in the MD direction at the fold line P (middle in the MD direction) so that the heat-sealable resin layers faced each other (FIG. 7b). The heat-sealable resin layers were heat-sealed approximately 10 mm inside the MD direction from the fold line P under the conditions of a seal width of 7 mm, a temperature of 190°C, a surface pressure of 1.0 MPa, and a time of 3 seconds (FIG. 7c). In Figure 7c, the shaded area S indicates the heat-sealed portion. Next, the specimen 13 was cut in the MD direction (cut at the position of the two-dot chain line in Figure 7d) so that the width in the TD direction was 15 mm to obtain a test piece (Figure 7e). Next, the test piece 13 was left at each measurement temperature for 5 minutes, and the heat-sealable resin layer of the heat-sealed portion was peeled off at a rate of 300 mm / min using a tensile tester (Shimadzu Corporation, AG-I (product name)) at each measurement temperature environment (Figure 8). The maximum strength at the time of peeling was defined as the seal strength (N / 15 mm). The distance between the chucks was 50 mm. The results are shown in Table 1A. Note that in measuring the seal strength, the test piece 13 may peel off (fracture) at the heat-seal interface A shown in Figure 8, or may fracture at a location other than the heat-seal interface A (e.g., position B in Figure 8). If the test piece 13 fractured, the fracture strength was recorded as the seal strength in Table 1A. The evaluation criteria for the seal strength at 25°C and the seal strength at 150°C are shown below.

[0273] (Evaluation criteria for seal strength at 25°C) A: Seal strength of 140.0 N / 15 mm or more B: Seal strength of less than 140.0 N / 15 mm

[0274] (Evaluation criteria for seal strength (heat resistance) at 150°C) A: Seal strength of 25.0 N / 15 mm or more B: Seal strength of 10.0 N / 15 mm or more but less than 25.0 N / 15 mm C: Seal strength less than 10.0 N / 15 mm

[0275] <Evaluation of Electrolyte Resistance> A sample was prepared from an exterior packaging material for an electricity storage device cut to a size of 90 mm in TD × 200 mm in MD, as shown in the schematic diagram of Fig. 10. The sample was folded at a position 100 mm in MD, and in the folded state, both ends in the TD direction were heat-sealed under conditions of a width of 7 mm, a surface pressure of 1.0 MPa, a sealing temperature of 190°C, and a sealing time of 3.0 seconds, to prepare a bag-shaped package having an opening formed from the exterior packaging material for an electricity storage device. Next, the bag-shaped package was stored for 1 day in a dry room with a dew point of -40 ° C., and the remaining open edge (opening) was filled with an electrolyte solution (a solution obtained by mixing ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1:1:1 in a volume ratio and mixing lithium hexafluorophosphate to a concentration of 1 mol / L). The opening was heat-sealed under conditions of a width of 7 mm, a surface pressure of 1.0 MPa, a sealing temperature of 190 ° C., and a sealing time of 3.0 seconds, and the electrolyte was sealed inside the package. The package was stored for 14 days in an 85 ° C. environment with the heat-sealed edge of the opened object facing up. After storage, the heat-sealed edge of the opened object was cut off to open it, the electrolyte was removed, and within 3 hours, the heat-sealable resin layers at the points where the electrolyte had been in contact were heat-sealed to each other perpendicular to the MD direction under conditions of a width of 7 mm, a surface pressure of 1.0 MPa, a sealing temperature of 190 ° C., and a sealing time of 3.0 seconds. A 15 mm wide sample was cut perpendicular to the TD direction to prepare a sample for measuring the seal strength when pulled in the MD direction. Within 1 hour of heat sealing, the impregnation seal strength (seal strength when the sample was impregnated with electrolyte) was measured after 14 days in an 85°C environment using the same equipment and conditions as for the seal strength in the 25°C environment described above. The measurement results of the impregnation seal strength, along with the observation results of the swelling state and peel mode of the seal strength measurement sample, are shown in Table 1A. The evaluation criteria for electrolyte resistance are as follows:

[0276] (Evaluation criteria for electrolyte resistance) A: Impregnation seal strength is 130.0 N / 15 mm or more and less than 300.0 N / 15 mm B: Impregnation seal strength is 20.0 N / 15 mm or more and less than 130.0 N / 15 mm C: Impregnation seal strength is less than 20.0 N / 15 mm

[0277] <Moldability Evaluation> Each electrical storage device exterior material was cut into a length (MD) x width (TD) of 55 mm to prepare a test sample. This test sample was molded using a rectangular molding die (female die) with a bore of 30.0 mm (MD) x 30.0 mm (TD) in an environment of 25°C. Cold molding (single-stage pull-in molding) was performed at a pressing pressure (surface pressure) of 0.18 MPa and a stroke speed of 20 mm / s to obtain a molding depth of 12.0 mm. The test sample was placed on the female die so that the heat-sealable resin layer was positioned on the male die side and molded. After molding, the heat-sealable resin layer of the test sample was visually observed to confirm the presence or absence of whitening. Whitening occurred mainly around the corners of the molded portion. The moldability evaluation criteria were as follows. The results are shown in Table 1A.

[0278] (Evaluation criteria for formability) A: No whitening B: Whitening around the corners of the molded part (whitened parts are within half the length of adjacent corners) C: Whitening throughout

[0279]

[0280] The values ​​of ΔE, strength ratio X, and seal strength in Table 1A are each calculated by rounding off the measured value that is one digit smaller than the value shown in Table 1A.

[0281] In Table 1A, rPP means random polypropylene, hPP means homopolypropylene, bPP means block polypropylene, PE means polyethylene, and AL means aluminum alloy foil.

[0282] The electrical storage device packaging materials of Examples 1A to 4A are composed of a laminate including at least a barrier layer and a heat-sealable resin layer in this order, and the heat-sealable resin layer has a logarithmic decrement ΔE of 0.075 or less at 150°C in rigid pendulum measurement. As shown in Table 1A, it can be seen that the electrical storage device packaging materials of Examples 1A to 4A have excellent heat resistance.

[0283] <Production of Second Aspect of Sheathing Material for Electricity Storage Device> Example 1B As the substrate layer, a laminate was prepared in which a biaxially oriented polyethylene terephthalate (PET) film (thickness 12 μm) and an oriented nylon (ONy) film (thickness 15 μm) were bonded together with an adhesive layer (formed with a two-component curing urethane adhesive, with a thickness of 3 μm after curing). Furthermore, as the barrier layer, aluminum foil (JIS H4160:1994 A8021H-O (thickness 40 μm)) was prepared. Both sides of the aluminum foil were subjected to a chemical conversion treatment. The chemical conversion treatment of the aluminum foil was carried out by applying a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid to a coating amount of chromium of 10 mg / m. 2 (dry mass) was applied to both sides of an aluminum foil by roll coating, and baked.

[0284] Next, a two-component curing urethane adhesive was used to bond the base material layer and the barrier layer together with an adhesive layer (thickness: 3 μm) by a dry lamination method, thereby producing a laminate in which the base material layer / adhesive layer / barrier layer were laminated in this order.

[0285] Next, on the barrier layer of each of the laminates obtained above, a resin composition forming an adhesive layer (40 μm thick) (a resin composition consisting of maleic anhydride-modified homopolypropylene, homopolypropylene, and a propylene-ethylene-butene copolymer elastomer (terpolymer)) and a resin composition forming a heat-sealable resin layer (40 μm thick) (a resin composition consisting of random polypropylene, homopolypropylene, and a propylene-ethylene copolymer elastomer (binary copolymer)) were co-extruded, thereby laminating the adhesive layer / heat-sealable resin layer on the barrier layer. Next, the obtained laminate was aged and heated to obtain an exterior packaging material for an electricity 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.

[0286] Example 2B An exterior material for an electricity storage device comprising a laminate in which a base layer / adhesive layer / barrier layer / adhesive layer / thermally fusible resin layer were laminated in this order was obtained in the same manner as in Example 1B, except that a resin composition comprising maleic anhydride-modified homopolypropylene, homopolypropylene, and a propylene-ethylene copolymer elastomer (binary copolymer) was used as the resin composition forming the adhesive layer (thickness 40 μm).

[0287] In Examples 1B and 2B, when the thickness of the barrier layer was increased from 40 μm to 60 μm and further to 80 μm, the seal strength in an environment of 25°C and that of 150°C increased, the water vapor barrier properties were excellent, and whitening did not occur during molding. These results show that the thickness of the barrier layer is not limited to 40 μm and may be increased, for example, to 80 μm.

[0288] Comparative Example 1B An exterior material for a storage battery device was obtained in the same manner as in Example 1B, except that maleic anhydride-modified homopolypropylene was used as the resin forming the adhesive layer (thickness 40 μm), and a resin composition composed of random polypropylene, polyethylene, and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin composition forming the heat-sealable resin layer (thickness 40 μm). The exterior material was a laminate in which the base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0289] Comparative Example 2B An exterior material for a storage battery device consisting of a laminate in which a base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order was obtained in the same manner as in Example 1B, except that a resin composition consisting of maleic anhydride-modified homopolypropylene, block polypropylene, and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin composition forming the adhesive layer (thickness 40 μm), and a resin composition consisting of block polypropylene and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin composition forming the heat-sealable resin layer (thickness 40 μm).

[0290] Comparative Example 3B An exterior packaging material for an electricity storage device was obtained, which consisted of a laminate in which a base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order, in the same manner as in Comparative Example 1B, except that a resin composition composed of random polypropylene, block polypropylene, and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin composition for forming the heat-sealable resin layer (thickness: 40 μm).

[0291] Comparative Example 4B An exterior packaging material for an electricity storage device was obtained, which consisted of a laminate in which a base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order, in the same manner as in Example 1B, except that a resin composition composed of random polypropylene, homopolypropylene, and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin composition for forming the heat-sealable resin layer (thickness 40 μm).

[0292] <Cross-sectional observation of heat-sealable resin layer> An electrical storage device casing material was embedded in a thermosetting epoxy resin and cured. A cross-section was prepared using a commercially available rotary microtome (LEICA EM UC6), and the heat-sealable resin layer of the electrical storage device casing material, along with the embedded resin, was stained with ruthenium tetroxide for 3 hours. After cutting the cross-section 1 μm deep using the microtome, stained sections with thicknesses of 70 nm to 100 nm were obtained using a diamond knife. Cross-sectional images of the stained sections were obtained using a field emission scanning electron microscope (Hitachi High-Technologies Corporation S-4800). The measurement conditions were an acceleration voltage of 30 kV, an emission current of 10 μA, a transmission detector, and no tilt (0°). The sea-island structure was observed at a magnification of 20,000x, and the lamellar structure was observed at a magnification of 50,000x. For the cross-sectional image of the sea-island structure of the heat-fusible resin layer, a 4.50 μm × 6.37 μm area was randomly selected from a 13.5 μm × 19.1 μm area in the central portion of the heat-fusible resin layer at a magnification of 20,000 times to confirm the number of islands contained in the 4.50 μm × 6.37 μm area. Furthermore, the island areas observed at a magnification of 20,000 times were further enlarged to 50,000 times to observe whether or not the islands contained lamellae and whether or not the islands contained a layer with a thickness of 10 nm or more at the boundary between the island and sea portions. The results are shown in Table 1B.

[0293] <Measurement of Logarithmic Decay Rate ΔE by Rigid Pendulum Measurement> A schematic diagram illustrating the method for measuring the logarithmic decay rate ΔE by rigid pendulum measurement is shown in Figure 6. A rigid pendulum-type physical property tester (model number: RPT-3000W, manufactured by A&D Co., Ltd.) was used, with FRB-100 used for the frame of the pendulum 30, RBP-020 used for the cylindrical cylinder edge 30a of the edge portion, and CHB-100 used for the cooling block 31, and the initial amplitude was approximately 0.3 degrees. The pendulum adsorption time was 1.0 seconds, and the measurement interval was 10 seconds. The test sample was cut to 45 mm in MD and 15 mm in TD. In addition, a vibration displacement detector 32 was used.

[0294] The cylindrical cylinder edge RBP-020 used in this measurement has a small diameter of 2 mm, and is easily sunk from the surface to the interior of the heat-sealable resin layer during measurement, making it suitable for evaluating the properties of the heat-sealable resin layer as a whole. For this reason, this measurement is suitable from the perspective of evaluating the correlation with the seal strength in a high-temperature environment (150°C environment) described below.

[0295] The test sample was placed on a cooling block 31 with the measurement surface (thermal adhesive resin layer) facing upward, and the cylindrical cylinder edge 30a with a pendulum was installed on the measurement surface so that its axial direction was perpendicular to the MD direction of the test sample. To prevent the test sample from lifting or warping during measurement, tape was attached to a location on the cooling block 31 that would not affect the measurement results. The cylindrical cylinder edge 30a was brought into contact with the surface of the thermal adhesive resin layer. Next, the logarithmic decrement ΔE of the thermal adhesive resin layer was measured using the cooling block 31 at a temperature increase rate of 3°C / min over a temperature range from 0°C to 180°C (N=1). The logarithmic decrement ΔE was measured when the surface temperature of the thermal adhesive resin layer of the test sample (exterior material for an electricity storage device) reached 150°C. The results are shown in Table 1B. A logarithmic decay factor ΔE at 150°C of 0.075 or less was used in this measurement as an index for achieving a heat-resistant seal strength of 25 N / 15 mm or more at 150°C (described later). The logarithmic decay factor ΔE was calculated using the following formula. The value was rounded to the nearest tenth to calculate the third decimal place. ΔE = [ln(A1 / A2) + ln(A2 / A3) + . . . + ln(An / An+1)] / n, where A is amplitude and n is wave number.

[0296] In Examples 1B to 2B, the logarithmic decrement ΔE of the heat-sealable resin layer in an 80°C environment was all greater than 0.02. The logarithmic decrement ΔE of the heat-sealable resin layer in an 80°C environment is a value measured in the same manner as the logarithmic decrement ΔE of the heat-sealable resin layer in a 150°C environment in the method described in <Measurement of logarithmic decrement ΔE by rigid pendulum measurement> above, except that "the logarithmic decrement ΔE when the surface temperature of the heat-sealable resin layer of the test sample (exterior material for an electricity storage device) is used when the surface temperature is 80°C" is replaced with "the logarithmic decrement ΔE when the surface temperature of the heat-sealable resin layer of the test sample (exterior material for an electricity storage device) is used when the surface temperature is 150°C."

[0297] <Evaluation of Water Vapor Barrier Property of Packaging Body Formed from Electricity Storage Device Exterior Material> The water vapor barrier property of packaging body formed from the electricity storage device exterior material was evaluated according to the following procedure. (Procedure) As shown in the schematic diagram of FIG. 11 , the electricity storage device exterior material was cut to 75 mm in TD x 150 mm in MD to serve as a sample. The sample was folded at a 75 mm MD location, and in the folded state, both ends in the TD direction were heat-sealed under conditions of a width of 7 mm, a surface pressure of 1.0 MPa, a sealing temperature of 190°C, and a sealing time of 3.0 seconds to form a bag-shaped package formed from the electricity storage device exterior material and having an opening. The sealed portions at both ends in the TD direction were designated as the left and right sealed portions. At this time, the thicknesses of the left and right sealed portions were measured with a thickness meter, and the thicknesses of the substrate layer, barrier layer, and adhesive layer were subtracted from the respective left and right thicknesses (only the thickness of the layer closer to the heat-sealable resin layer than the barrier layer) to determine the thickness of the sealed portion. Next, the left and right sealed portions at both ends were cut to 3.0 mm. The 3.0 mm seal after cutting is the water vapor permeation distance. Next, the bag-shaped package is stored for one day in a dry room with a dew point of -40°C, and 2.0 g of solution (a solution containing ethylene carbonate, diethyl carbonate, and dimethyl carbonate mixed in a volume ratio of 1:1:1) is poured into the remaining open edge (opening). The opening is heat-sealed under conditions of a width of 7 mm, a surface pressure of 1.0 MPa, a sealing temperature of 190°C, and a sealing time of 3.0 seconds to seal the solution inside the package. The sealed portion into which the solution was poured is defined as the upper portion. The film thickness of the upper sealed portion is measured with a film thickness meter, and the value obtained by subtracting the thicknesses of the base layer, barrier layer, and adhesive layer (only the thickness of the layer on the heat-sealable resin layer side of the barrier layer) is defined as the seal film thickness. The upper sealed portion created by sealing the opening is cut to 3.0 mm. The 3.0 mm seal after cutting is the water vapor permeation distance. The length of each sealed portion (left and right sides and the top portion where the solution is sealed) of the package containing the solution is measured with a metal ruler. 2is set according to the following formula: Water vapor permeation cross section = Cross section of both ends (Right seal film thickness × Right length + Left seal film thickness × Left length) + Upper cross section (Upper seal film thickness × Upper seal length) The moisture content (ppm) of the solution at the time of sealing is measured using coulometric titration according to the Karl Fischer method. The solution is left for 4 weeks in a thermo-humidistat chamber at a temperature of 65°C and a relative humidity of 90%, and the moisture content per 2.0 g of solution after the test is measured. The moisture content after 4 weeks of storage is also measured using coulometric titration according to the Karl Fischer method, in the same way as at the time of sealing (before storage). The moisture content (ppm) measured after 4 weeks of storage at a temperature of 65°C and a relative humidity of 90%, the moisture content (ppm) at the time of sealing (before putting into the thermo-humidistat chamber at a temperature of 65°C and a relative humidity of 90%), the amount of solution sealed (g), and the water vapor permeation cross section (m 2 ), and the time (days) at a temperature of 65°C and a relative humidity of 90% were used to calculate the water vapor permeability coefficient (g mm / m 2 ・day) is calculated. At this time, the value is rounded to one decimal place to calculate the value to one decimal place. Water vapor transmission coefficient = (water vapor transmission distance × (water content measured after leaving at a temperature of 65°C and a relative humidity of 90% for 4 weeks - water content at the time of encapsulation) × amount of encapsulated solution) / (water vapor transmission cross-sectional area × insertion time at a temperature of 65°C and a relative humidity of 90%)

[0298] For the evaluation of the water vapor barrier property at a temperature of 40°C and a relative humidity of 90%, the water vapor permeability coefficient (g mm / m) was measured in the same manner as in the evaluation of the water vapor barrier property at a temperature of 65°C and a relative humidity of 90% described above, except that the temperature and humidity chamber at a temperature of 65°C and a relative humidity of 90% was changed to a temperature and humidity chamber at a temperature of 40°C and a relative humidity of 90%. 2 The results of the calculation and evaluation are shown in Table 1B.

[0299] (Evaluation criteria for water vapor barrier property at a temperature of 65°C and a relative humidity of 90%) A: 4.5 g mm / m 2 Less than day B: 4.5 g mm / m 2 ・day or more 5.0 g・mm / m 2 Less than day C: 5.0 g mm / m 2 ・day or more

[0300] (Evaluation criteria for water vapor barrier property at a temperature of 40°C and a relative humidity of 90%) A: 0.60 g mm / m 2 Less than day B: 0.60 g mm / m 2 ・More than 0.68g・mm / m 2 Less than day C: 0.68 g mm / m 2 ・day or more

[0301] <Measurement of Seal Strength at 25°C or 150°C> In accordance with the provisions of JIS K7127:1999, the seal strength of the electrical storage device exterior material was measured at each measurement temperature of a 25°C environment and a 150°C environment as follows. Test pieces were prepared by cutting the electrical storage device exterior material into strips with a width of 15 mm in the TD direction. Specifically, as shown in FIG. 7, each electrical storage device exterior material was first cut into 75 mm (TD direction) x 150 mm (MD direction) (FIG. 7a). Next, the electrical storage device exterior material was folded in half in the MD direction at the fold line P (middle in the MD direction) so that the heat-sealable resin layers faced each other (FIG. 7b). The heat-sealable resin layers were heat-sealed approximately 10 mm inside the MD direction from the fold line P under the conditions of a seal width of 7 mm, a temperature of 190°C, a surface pressure of 1.0 MPa, and a time of 3 seconds (FIG. 7c). In Figure 7c, the shaded area S indicates the heat-sealed portion. Next, the specimen 13 was cut in the MD direction (cut at the position of the two-dot chain line in Figure 7d) so that the width in the TD direction was 15 mm, obtaining a test piece (Figure 7e). Next, the test piece 13 was left at each measurement temperature for 5 minutes, and the heat-sealable resin layer of the heat-sealed portion was peeled off at a rate of 300 mm / min using a tensile tester (Shimadzu Corporation, AG-I (product name)) at each measurement temperature environment (Figure 8). The maximum strength at the time of peeling was defined as the seal strength (N / 15 mm). The distance between the chucks was 50 mm. The results are shown in Table 1B. Note that in measuring the seal strength, the test piece 13 may peel off (fracture) at the heat-seal interface A shown in Figure 8, or may fracture at a location other than the heat-seal interface A (e.g., position B in Figure 8). If the test piece 13 fractured, the fracture strength was recorded as the seal strength in Table 1B. The evaluation criteria for the seal strength at 25°C and the seal strength at 150°C are shown below.

[0302] (Evaluation criteria for seal strength at 25°C) A: Seal strength of 140.0 N / 15 mm or more B: Seal strength of less than 140.0 N / 15 mm

[0303] (Evaluation criteria for seal strength (heat resistance) at 150°C) A: Seal strength of 25.0 N / 15 mm or more B: Seal strength of 10.0 N / 15 mm or more but less than 25 N / 15 mm C: Seal strength less than 10.0 N / 15 mm

[0304] <Moldability Evaluation> Each electrical storage device exterior material was cut into a length (MD) x width (TD) of 55 mm to prepare a test sample. This test sample was molded using a rectangular molding die (female die) with a bore of 30.0 mm (MD) x 30.0 mm (TD) in an environment of 25°C. Cold molding (single-stage pull-in molding) was performed at a pressing pressure (surface pressure) of 0.18 MPa and a stroke speed of 20 mm / s to obtain a molding depth of 12.0 mm. The test sample was placed on the female die so that the heat-sealable resin layer was located on the male die side and molded. After molding, the heat-sealable resin layer of the test sample was visually observed to confirm the presence or absence of whitening. Whitening occurred mainly at the corners of the molded portion. The moldability evaluation criteria were as follows. The results are shown in Table 1B.

[0305] (Evaluation criteria for formability) A: No whitening B: Whitening around the corners of the molded part (whitened parts are within half the length of adjacent corners) C: Whitening throughout

[0306]

[0307] The values ​​of ΔE and seal strength in Table 1B are values ​​calculated by rounding off the measured values ​​that are one digit smaller than the values ​​shown in Table 1B.

[0308] In Table 1B, rPP means random polypropylene, hPP means homopolypropylene, bPP means block polypropylene, and PE means polyethylene.

[0309] The electrical storage device packaging material of Example 1B-2B is composed of a laminate including at least a barrier layer and a heat-sealable resin layer in this order, and a sea-island structure is observed in a cross-sectional image of the heat-sealable resin layer in a direction parallel to the TD and thickness direction, obtained using a field emission scanning electron microscope. When the cross-sectional image is observed at a magnification of 20,000 times over an area of ​​4.50 μm × 6.37 μm, the number of island portions having a maximum diameter of 100 nm or more and less than 300 nm is 10 or less, and no island portion having a maximum diameter of 300 nm or more is included. When the cross-sectional image is observed at a magnification of 50,000 times over, lamellae are observed in the island portions. As shown in Table 1B, the electrical storage device packaging material of Example 1B-2B has excellent water vapor barrier properties.

[0310] <Production of the Third Aspect of the Exterior Material for an Electrical Storage Device> Example 1C As the substrate layer, a laminate was prepared in which a biaxially oriented polyethylene terephthalate (PET) film (thickness: 12 μm) and an oriented nylon (ONy) film (thickness: 15 μm) were bonded together with an adhesive layer (formed with a two-component curing urethane adhesive, with a thickness of 3 μm after curing). Furthermore, as the barrier layer, aluminum foil (JIS H4160:1994 A8021H-O (thickness: 40 μm)) was prepared. Both sides of the aluminum foil were subjected to a chemical conversion treatment. The chemical conversion treatment of the aluminum foil was carried out by applying a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid to a coating amount of chromium of 10 mg / m. 2 (dry mass) was applied to both sides of an aluminum foil by roll coating, and baked.

[0311] Next, a two-component curing urethane adhesive was used to bond the base material layer and the barrier layer together with an adhesive layer (thickness: 3 μm) by a dry lamination method, thereby producing a laminate in which the base material layer / adhesive layer / barrier layer were laminated in this order.

[0312] Next, a laminate of a resin composition (a resin composition consisting of maleic anhydride-modified homopolypropylene, homopolypropylene, and a propylene-ethylene-butene copolymer elastomer (a ternary copolymer)) forming an adhesive layer (40 μm thick) and a resin composition (a resin composition consisting of random polypropylene, homopolypropylene, and a propylene-ethylene copolymer elastomer (a binary copolymer)) forming a heat-sealable resin layer (40 μm thick) was produced by co-extrusion. With the adhesive layer side of a laminate consisting of an adhesive layer and a heat-sealable resin layer placed on the barrier layer of a laminate consisting of a base layer / adhesive layer / barrier layer, a packaging material for an electricity storage device was obtained, consisting of a laminate in which the base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0313] Example 2C An exterior material for a storage battery device comprising a laminate in which a base layer / adhesive layer / barrier layer / adhesive layer / thermally fusible resin layer were laminated in this order was obtained in the same manner as in Example 1C, except that a resin composition comprising maleic anhydride-modified homopolypropylene, homopolypropylene, and a propylene-ethylene copolymer elastomer (binary copolymer) was used as the resin composition forming the adhesive layer (thickness 40 μm).

[0314] Example 3C An exterior material for a storage battery device consisting of a laminate in which a base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order was obtained in the same manner as in Example 1C, except that a resin composition consisting of maleic anhydride-modified homopolypropylene, block polypropylene, and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin composition forming the adhesive layer (thickness 40 μm), and a resin composition consisting of block polypropylene and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin composition forming the heat-sealable resin layer (thickness 40 μm).

[0315] In Examples 1C to 3C, when the thickness of the barrier layer was increased from 40 μm to 60 μm and further to 80 μm, the seal strength in an environment of 25° C. and the seal strength in an environment of 150° C. increased, the insulating properties were excellent, and whitening did not occur during molding. This result shows that the thickness of the barrier layer is not limited to 40 μm and may be increased, for example, to 80 μm.

[0316] Comparative Example 1C An exterior material for a storage battery device was obtained in the same manner as in Example 1C, except that maleic anhydride-modified homopolypropylene was used as the resin forming the adhesive layer (thickness 40 μm), and a resin composition composed of random polypropylene, polyethylene, and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin forming the heat-sealable resin layer (thickness 40 μm). The exterior material was a laminate in which the base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0317] Comparative Example 2C An exterior packaging material for an electricity storage device was obtained, which consisted of a laminate in which a base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order, in the same manner as in Comparative Example 1C, except that a resin composition composed of random polypropylene, block polypropylene, and a propylene-ethylene-butene copolymer elastomer (ternary copolymer) was used as the resin for forming the heat-sealable resin layer (thickness: 40 μm).

[0318] <Evaluation of Heat-Fusible Resin Layer by Differential Scanning Calorimetry (Obtaining a DSC Curve)> For the heat-fusible resin layer of the exterior material for an electricity storage device, a DSC curve of the resin forming the heat-fusible resin layer was obtained by differential scanning calorimetry (DSC) in accordance with the provisions of JIS K7121:2012 (Method for measuring transition temperature of plastics). 5-10 mg of the heat-fusible resin layer was placed in an aluminum pan, covered, and then a DSC curve was obtained using a differential scanning calorimeter (Shimadzu DSC-60). The measurements were performed in a temperature range from -10°C to 200°C at a heating rate of 10°C / min and a cooling rate of -10°C / min. Once the temperature reached 200°C, the sample was held at 200°C for 10 minutes. After the temperature was further lowered, the sample was held at -10°C for 10 minutes. This eliminated the thermal history and allowed the resin to perform its intended function. A DSC curve was obtained from the second heating cycle after the first heating and cooling cycle. From the resulting DSC curve, the melting peak temperature of the heat-fusible resin layer and a shoulder peak in the temperature range above 100.0°C were confirmed. The measurements were performed in a nitrogen atmosphere with a nitrogen gas flow rate of 50 mL / min. The results are shown in Table 1C. The melting peak temperature and shoulder peak temperature are rounded to one decimal place. The shoulder peak is the portion of the DSC curve in the temperature range from the extrapolated melting onset temperature to the melting peak temperature, where the slope of the curve changes on the lower side than the melting peak temperature. This is also called a shoulder peak. The shoulder peak temperature is preferably determined as follows (i) and (ii) with reference to JIS K7121 (Method for Measuring Transition Temperature of Plastics). (i) The shoulder peak temperature is the temperature at the apex of the shoulder peak. (ii) When the shoulder peak temperature is gentle and the apex is difficult to determine, the shoulder peak temperature is the temperature at the intersection of a tangent drawn to the curve on the low-temperature side of the shoulder peak at the point where the gradient is maximum and a tangent drawn to the curve on the high-temperature side of the shoulder peak at the point where the gradient is minimum. For example, in Example 1C, the melting point peak exceeds 160.0°C and the shoulder peak also exceeds 150.0°C. On the other hand, in Comparative Example 1, the melting point peak is 160.0°C or less and the shoulder peak is 150.0°C or less, and in Comparative Example 2, the melting point peak is 160.0°C or more and the shoulder peak is 150.0°C or less. When there are two or more shoulder peak temperatures, as in Comparative Example 2, the shoulder peak temperature with the highest temperature was evaluated.

[0319] (Evaluation criteria for peak melting temperature) A: Peak melting temperature is 160.0°C or higher C: Peak melting temperature is less than 160.0°C

[0320] (Evaluation criteria for shoulder peak temperature) A: Shoulder peak temperature is greater than 150.0°C C: Shoulder peak temperature is 100.0°C or more and 150.0°C or less

[0321] <Measurement of logarithmic attenuation factor ΔE by rigid pendulum measurement> A schematic diagram illustrating the method for measuring the logarithmic attenuation factor ΔE by rigid pendulum measurement is shown in Figure 6. A rigid pendulum-type physical property tester (model number: RPT-3000W, manufactured by A&D Co., Ltd.) was used, with FRB-100 used for the frame of the pendulum 30, RBP-020 used for the cylindrical cylinder edge 30a of the edge portion, and CHB-100 used for the cooling block 31, and the initial amplitude was approximately 0.3 degrees. The pendulum adsorption time was 1.0 seconds, and the measurement interval was 10 seconds. The test sample was cut to MD 45 mm and TD 15 mm. Furthermore, a vibration displacement detector 32 was used.

[0322] The cylindrical cylinder edge RBP-020 used in this measurement has a small diameter of 2 mm, and is easily sunk from the surface to the interior of the heat-sealable resin layer during measurement, making it suitable for evaluating the properties of the heat-sealable resin layer as a whole. For this reason, this measurement is suitable from the perspective of evaluating the correlation with the seal strength in a high-temperature environment (150°C environment) described below.

[0323] The test sample was placed on a cooling block 31 with the measurement surface (thermal adhesive resin layer) facing upward, and the cylindrical cylinder edge 30a with a pendulum was placed on the measurement surface so that its axial direction was perpendicular to the MD direction of the test sample. To prevent the test sample from lifting or warping during measurement, tape was attached to a location on the cooling block 31 that would not affect the measurement results. The cylindrical cylinder edge 30a was brought into contact with the surface of the thermal adhesive resin layer. Next, the logarithmic decrement ΔE of the thermal adhesive resin layer was measured using the cooling block 31 at a temperature increase rate of 3°C / min over a temperature range from 0°C to 180°C (N=1). The logarithmic decrement ΔE was measured when the surface temperature of the thermal adhesive resin layer of the test sample (exterior material for an electric storage device) reached 150°C. The results are shown in Table 1C. A logarithmic decay factor ΔE at 150°C of 0.075 or less was used in this measurement as an index for achieving a heat-resistant seal strength of 25 N / 15 mm or more at 150°C (described later). The logarithmic decay factor ΔE was calculated using the following formula. The value was rounded to the nearest tenth to calculate the third decimal place. ΔE = [ln(A1 / A2) + ln(A2 / A3) + . . . + ln(An / An+1)] / n, where A is amplitude and n is wave number.

[0324] In Examples 1C to 3C, the logarithmic decrement ΔE of the heat-sealable resin layer in an 80°C environment was all greater than 0.02. The logarithmic decrement ΔE of the heat-sealable resin layer in an 80°C environment was a value measured in the same manner as the logarithmic decrement ΔE of the heat-sealable resin layer in a 150°C environment in the method described in <Measurement of logarithmic decrement ΔE by rigid pendulum measurement> above, except that "the logarithmic decrement ΔE when the surface temperature of the heat-sealable resin layer of the test sample (exterior material for an electricity storage device) is used when the surface temperature is 80°C" is used instead of "the logarithmic decrement ΔE when the surface temperature of the heat-sealable resin layer of the test sample (exterior material for an electricity storage device) is used when the surface temperature is 150°C."

[0325] <Measurement of Seal Strength at 25°C or 150°C> In accordance with the provisions of JIS K7127:1999, the seal strength of the electrical storage device exterior material was measured at each measurement temperature of a 25°C environment and a 150°C environment as follows. Test pieces were prepared by cutting the electrical storage device exterior material into strips with a width of 15 mm in the TD direction. Specifically, as shown in FIG. 7, each electrical storage device exterior material was first cut into 75 mm (TD direction) x 150 mm (MD direction) (FIG. 7a). Next, the electrical storage device exterior material was folded in half in the MD direction at the fold line P (middle in the MD direction) so that the heat-sealable resin layers faced each other (FIG. 7b). The heat-sealable resin layers were heat-sealed approximately 10 mm inside the MD direction from the fold line P under the conditions of a seal width of 7 mm, a temperature of 190°C, a surface pressure of 1.0 MPa, and a time of 3 seconds (FIG. 7c). In Figure 7c, the shaded area S indicates the heat-sealed portion. Next, the specimen 13 was cut in the MD direction (cut at the position of the two-dot chain line in Figure 7d) so that the width in the TD direction was 15 mm to obtain a test piece (Figure 7e). Next, the test piece 13 was left at each measurement temperature for 5 minutes, and the heat-sealable resin layer of the heat-sealed portion was peeled off at a rate of 300 mm / min using a tensile tester (Shimadzu Corporation, AG-I (product name)) at each measurement temperature environment (Figure 8). The maximum strength at the time of peeling was defined as the seal strength (N / 15 mm). The distance between the chucks was 50 mm. The results are shown in Table 1C. Note that in measuring the seal strength, the test piece 13 may peel off (fracture) at the heat-sealed interface A shown in Figure 8, or may fracture at a location other than the heat-sealed interface A (for example, position B in Figure 8). If the test piece 13 fractured, the fracture strength was recorded as the seal strength in Table 1C. The evaluation criteria for the seal strength at 25°C and the seal strength at 150°C are shown below.

[0326] (Evaluation criteria for seal strength at 25°C) A: Seal strength of 140.0 N / 15 mm or more B: Seal strength of less than 140.0 N / 15 mm

[0327] (Evaluation criteria for seal strength (heat resistance) at 150°C) A: Seal strength of 25.0 N / 15 mm or more B: Seal strength of 10.0 N / 15 mm or more but less than 25 N / 15 mm C: Seal strength less than 10.0 N / 15 mm

[0328] <Insulation Evaluation (Volume Resistivity) in a 150°C Environment> The electrical storage device exterior material was cut to a 10 cm x 10 cm size, and the film thickness was measured. The volume resistivity of the electrical storage device exterior material was measured using a Digital Ultra-High Resistance / Micro-Current Meter 5450 manufactured by ADC Corporation in accordance with the provisions of IEC 62631-3-1 to 3-2. The sample was placed in a Resistivity Chamber 12708 manufactured by ADC Corporation, set to 150°C, and after 3 minutes when the temperature had stabilized at 150°C, 500 V was applied. The volume resistivity was calculated from the current value and film thickness after 1 minute. The results are shown in Table 1C.

[0329] (Evaluation criteria for insulation properties) A: Volume resistivity in a 150°C environment is 1.0 × 10 14 B: The volume resistivity in a 150°C environment is 5.0 × 10 13 Ω・cm or more 1×10 14 C: The volume resistivity in a 150°C environment is less than 5.0 × 10 13 It is less than Ω·cm.

[0330] <Moldability Evaluation> Each electrical storage device exterior material was cut into a length (MD) x width (TD) of 55 mm to prepare a test sample. This test sample was molded using a rectangular molding die (female die) with a bore of 30.0 mm (MD) x 30.0 mm (TD) in an environment of 25°C. Cold molding (single-stage pull-in molding) was performed at a pressing pressure (surface pressure) of 0.18 MPa and a stroke speed of 20 mm / s to obtain a molding depth of 12.0 mm. The test sample was placed on the female die so that the heat-sealable resin layer was positioned on the male die side and molded. After molding, the heat-sealable resin layer of the test sample was visually observed to confirm the presence or absence of whitening. Whitening occurred mainly around the corners of the molded portion. The moldability evaluation criteria were as follows. The results are shown in Table 1C.

[0331] (Evaluation criteria for formability) A: No whitening B: Whitening around the corners of the molded part (whitened parts are within half the length of adjacent corners) C: Whitening throughout

[0332]

[0333] The values ​​of the melting peak temperature, shoulder peak temperature, ΔE, seal strength, and volume resistivity in Table 1C are each calculated by rounding off the measured value that is one digit smaller than the value shown in Table 1C.

[0334] In Table 1C, rPP means random polypropylene, hPP means homopolypropylene, bPP means block polypropylene, and PE means polyethylene. In addition, in the insulation evaluation section of Table 1C, for example, the index notation (E notation) "1.9E+14" in Example 1C is "1.9 × 10 14 The same index notation is used for Examples 2C and 3C and Comparative Examples 1C and 2C.

[0335] The electrical storage device packaging materials of Examples 1C-3C are composed of a laminate having at least a barrier layer and a heat-sealable resin layer in this order, and the heat-sealable resin layer has a melting peak temperature of 160.0°C or higher in a DSC curve obtained by differential scanning calorimetry, no shoulder peak in the temperature range of 100.0°C or higher and 150.0°C or lower, and a shoulder peak at a temperature above 150.0°C. As shown in Table 1C, it can be seen that the electrical storage device packaging materials of Examples 1C-3C have excellent heat resistance and insulating properties in high-temperature environments.

[0336] As described above, a first aspect of the present disclosure provides the following aspects of the invention. Item 1A. An exterior packaging material for an electricity storage device, which is composed of a laminate including at least a barrier layer and a heat-sealable resin layer in this order, wherein the heat-sealable resin layer has a logarithmic decrement ΔE of 0.075 or less at 150°C in a rigid pendulum measurement. Item 2A. In an absorption spectrum measured on the surface of the heat-sealable resin layer using an ATR measurement mode of FT-IR, a 973 cm peak attributable to an amorphous component is detected. -1 The absorption peak intensity P1 near 998 cm originating from the crystalline component -1Item 1A. The packaging material for an electricity storage device according to Item 1A, wherein the intensity ratio X = P2 / P1 of absorption peak intensities P2 near the peaks near the edge of the insulating film is 0.760 or more. Item 3A. The packaging material for an electricity storage device according to Item 1A or 2A, wherein the heat-sealable resin layer is formed from a resin composition containing random polypropylene, homopolypropylene, and an elastomer. Item 4A. The elastomer is a propylene-ethylene copolymer elastomer. Item 5A. The packaging material for an electricity storage device according to any one of Items 1A to 4A, wherein a sea-island structure is observed in a cross-sectional image of a cross section of the heat-sealable resin layer in a direction parallel to the TD and in the thickness direction, the cross-sectional image being obtained using a field emission scanning electron microscope, and when the cross-sectional image is observed at a magnification of 20,000 times over an area of ​​4.50 μm × 6.37 μm, the number of island portions having a maximum diameter of 100 nm or more and less than 300 nm is 10 or less, and the packaging material does not include any island portions having a maximum diameter of 300 nm or more. Item 6A. The packaging material for an electricity storage device according to Item 5A, wherein, when the cross-sectional image of the island portion is observed at a magnification of 50,000 times, lamellae crystals are observed in the island portion. Item 7A. The packaging material for an electricity storage device according to Item 5A or 6A, wherein, when the cross-sectional image of the island portion is observed at a magnification of 50,000 times, the island portion does not have a layer having a thickness of 10 nm or more at the boundary portion between the island portion and a sea portion. Item 8A. The packaging material for an electricity storage device according to any one of Items 1A to 7A, further comprising an adhesive layer between the barrier layer and the heat-sealable resin layer. Item 9A. The packaging material for an electricity storage device according to Item 8A, wherein the adhesive layer is formed from a resin composition containing acid-modified polypropylene and an elastomer, and further containing at least one of block polypropylene and homopolypropylene. Item 10A. The packaging material for an electricity storage device according to Item 9A, wherein the elastomer is a binary copolymer elastomer or a ternary copolymer elastomer. Item 11A. Item 12A. The packaging material for an electricity storage device according to any one of Items 1A to 11A, further comprising a substrate layer on the side of the barrier layer opposite to the heat-sealable resin layer.Item 13A. A method for producing a packaging material for an electricity storage device, comprising a step of obtaining a laminate having at least a base material layer, a barrier layer, and a heat-sealable resin layer laminated in this order, wherein the heat-sealable resin layer has a logarithmic decrement ΔE of 0.075 or less at 150°C in a rigid pendulum measurement. Item 14A. An electricity storage device, 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 packaging material for an electricity storage device according to any one of Items 1A to 12A.

[0337] As described above, a second aspect of the present disclosure provides the following aspects of the invention: Item 1B. An exterior packaging material for an electricity storage device, which is composed of a laminate including at least a barrier layer and a thermally adhesive resin layer in this order, wherein a sea-island structure is observed in a cross-sectional image of a cross section of the thermally adhesive resin layer in a direction parallel to the TD and in the thickness direction, obtained using a field emission scanning electron microscope, wherein when the cross-sectional image is observed at a magnification of 20,000 times over an area of ​​4.50 μm × 6.37 μm, the number of island portions having a maximum diameter of 100 nm or more and less than 300 nm is 10 or less and the number of island portions having a maximum diameter of 300 nm or more is 300 nm or less, and the island portion does not include any island portion having a maximum diameter of 300 nm or more, and when the cross-sectional image is observed at a magnification of 50,000 times over, lamellae are observed in the island portions. Item 2B. Item 1B. The packaging material for an electricity storage device according to Item 1B, wherein, when the island portion is observed in the cross-sectional image at a magnification of 50,000 times, the island portion does not have a layer with a thickness of 10 nm or more at the boundary portion between the island portion and a sea portion. Item 3B. The packaging material for an electricity storage device according to Item 1B or 2B, wherein the heat-sealable resin layer has a logarithmic decrement ΔE of 0.075 or less at 150°C in a rigid pendulum measurement. Item 4B. The packaging material for an electricity storage device according to any one of Items 1B to 3B, wherein the heat-sealable resin layer is formed from a resin composition containing random polypropylene, homopolypropylene, and an elastomer. Item 5B. The packaging material for an electricity storage device according to Item 4B, wherein the elastomer is a propylene-ethylene copolymer elastomer. Item 6B. The packaging material for an electricity storage device according to any one of Items 1B to 5B, further comprising an adhesive layer between the barrier layer and the heat-sealable resin layer. Item 7B. Item 6B. The electrical storage device packaging material according to Item 6B, wherein the adhesive layer is formed from a resin composition containing an acid-modified polypropylene and an elastomer, and further containing at least one of block polypropylene and homopolypropylene. Item 8B. The electrical storage device packaging material according to Item 7B, wherein the elastomer is a binary copolymer elastomer or a ternary copolymer elastomer. Item 9B. The electrical storage device packaging material according to any one of Items 1B to 8B, further comprising an adhesive layer between the base material layer and the barrier layer.Item 10B. The packaging material for an electricity storage device according to any one of Items 1B to 9B, further comprising a base material layer on the side of the barrier layer opposite the heat-sealable resin layer. Item 11B. A method for producing a packaging material for an electricity storage device, comprising a step of obtaining a laminate having at least a base material layer, a barrier layer, and a heat-sealable resin layer laminated in this order, wherein a sea-island structure is observed in a cross-sectional image of the heat-sealable resin layer in a direction parallel to the TD and in the thickness direction, obtained using a field emission scanning electron microscope, and when the cross-sectional image is observed at a magnification of 20,000 times over an area of ​​4.50 μm × 6.37 μm, the number of island portions having a maximum diameter of 100 nm or more and less than 300 nm is 10 or less, and the number of island portions having a maximum diameter of 300 nm or more is 300 nm or less, and when the cross-sectional image is observed at a magnification of 50,000 times over, lamellae are observed in the island portions. Item 12B. An electricity storage device, 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 packaging material for an electricity storage device according to any one of Items 1B to 10B.

[0338] As described above, a third aspect of the present disclosure provides the following aspects of the invention. Item 1C. An electrical storage device packaging material comprising a laminate including at least a barrier layer and a heat-sealable resin layer in this order, wherein the heat-sealable resin layer has a melting peak temperature of 160.0°C or higher, no shoulder peak in the temperature range of 100.0°C or higher and 150.0°C or lower, and a shoulder peak at a temperature above 150.0°C, in a DSC curve obtained by differential scanning calorimetry. Item 2C. The electrical storage device packaging material according to Item 1C, wherein the heat-sealable resin layer is formed from a resin composition containing random polypropylene, homopolypropylene, and an elastomer. Item 3C. The electrical storage device packaging material according to Item 2C, wherein the elastomer is a propylene-ethylene copolymer elastomer. Item 4C. The packaging material for an electricity storage device according to any one of Items 1C to 3C, wherein the heat-sealable resin layer has a logarithmic decrement ΔE of 0.075 or less at 150°C in a rigid pendulum measurement. Item 5C. The packaging material for an electricity storage device according to any one of Items 1C to 4C, further comprising an adhesive layer between the barrier layer and the heat-sealable resin layer. Item 6C. The packaging material for an electricity storage device according to Item 5C, wherein the adhesive layer is formed from a resin composition containing acid-modified polypropylene and an elastomer, and further containing at least one of block polypropylene and homopolypropylene. Item 7C. The packaging material for an electricity storage device according to Item 6C, wherein the elastomer is a binary copolymer elastomer or a ternary copolymer elastomer. Item 8C. The packaging material for an electricity storage device according to any one of Items 1C to 7C, further comprising an adhesive layer between the base layer and the barrier layer. Item 9C. Item 10C. A method for producing an electrical storage device packaging material according to any one of Items 1C to 8C, further comprising a base material layer on the opposite side of the barrier layer from the heat-sealable resin layer. Item 10C. A method for producing an electrical storage device packaging material, comprising a step of obtaining a laminate comprising at least a base material layer, a barrier layer, and a heat-sealable resin layer laminated in this order, wherein the heat-sealable resin layer has a melting peak temperature of 160.0°C or higher, no shoulder peak in the temperature range of 100.0°C to 150.0°C, and a shoulder peak at a temperature above 150.0°C, in a DSC curve obtained by differential scanning calorimetry.Item 11C: An electricity storage device, 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 packaging material for an electricity storage device according to any one of Items 1C to 9C.

[0339] REFERENCE SIGNS LIST 1 substrate layer 2 adhesive layer 3 barrier layer 4 heat-sealable resin layer 5 adhesive layer 6 surface coating layer 10 packaging material for electricity storage device 13 test piece

Claims

1. An exterior material for an electricity storage device, which is composed of a laminate having at least a barrier layer and a heat-sealable resin layer in this order, and the heat-sealable resin layer has a logarithmic decrement ΔE of 0.075 or less at 150°C in a rigid pendulum measurement.

2. In the absorption spectrum measured on the surface of the heat-sealing resin layer using the ATR measurement mode of FT-IR, a 973 cm -1 The absorption peak intensity P1 at 998 cm originating from the crystalline component -1 2. The exterior packaging material for an electricity storage device according to claim 1, wherein an intensity ratio X=P2 / P1 of an absorption peak intensity P2 near the absorption peak intensity P1 is 0.760 or more.

3. An exterior material for an electricity storage device, which is composed of a laminate having at least a barrier layer and a heat-sealable resin layer in this order, wherein a sea-island structure is observed in a cross-sectional image obtained using a field emission scanning electron microscope for a cross section of the heat-sealable resin layer in a direction parallel to the TD and in the thickness direction, wherein when the cross-sectional image is observed over an area of ​​4.50 μm × 6.37 μm at a magnification of 20,000 times, the number of islands having a maximum diameter of 100 nm or more and less than 300 nm is 10 or less, and the island does not include any island having a maximum diameter of 300 nm or more, and wherein when the cross-sectional image is observed over a range of 4.50 μm × 6.37 μm at a magnification of 50,000 times, lamellar crystals are observed in the islands.

4. The exterior material for an electricity storage device as described in claim 3, wherein when the island portion is observed in the cross-sectional image at a magnification of 50,000 times, the island portion does not have a layer having a thickness of 10 nm or more at the boundary portion between the island portion and a sea portion.

5. An exterior material for an electricity storage device, which is composed of a laminate having at least a barrier layer and a heat-sealable resin layer in this order, and in a DSC curve obtained by differential scanning calorimetry, the heat-sealable resin layer has a melting peak temperature of 160.0°C or higher, no shoulder peak in the temperature range of 100.0°C to 150.0°C, and a shoulder peak at a temperature above 150.0°C.

6. An exterior material for a storage battery device according to claim 1 or 5, wherein a sea-island structure is observed in a cross-sectional image obtained by using a field emission scanning electron microscope for a cross-section of the heat-sealable resin layer in a direction parallel to the TD and in the thickness direction, and when the cross-sectional image is observed over an area of ​​4.50 μm × 6.37 μm at a magnification of 20,000 times, the number of islands having a maximum diameter of 100 nm or more and less than 300 nm is 10 or less, and no island has a maximum diameter of 300 nm or more.

7. The exterior material for an electricity storage device according to claim 6, wherein, when the island portion is observed in the cross-sectional image at a magnification of 50,000 times, lamellar crystals are observed in the island portion.

8. The exterior material for an electricity storage device as described in claim 6, wherein when the island portion is observed in the cross-sectional image at a magnification of 50,000 times, the island portion does not have a layer having a thickness of 10 nm or more at the boundary portion between the island portion and a sea portion.

9. The exterior packaging material for an electricity storage device according to any one of claims 1 to 5, wherein the heat-sealable resin layer has a logarithmic decrement ΔE of 0.075 or less at 150°C in rigid pendulum measurement.

10. An exterior packaging material for an electricity storage device according to any one of claims 1 to 5, wherein the heat-sealable resin layer is formed from a resin composition containing random polypropylene, homopolypropylene and an elastomer.

11. The exterior packaging material for an electricity storage device according to claim 10, wherein the elastomer is a propylene-ethylene copolymer elastomer.

12. The packaging material for an electricity storage device according to any one of claims 1 to 5, further comprising an adhesive layer between the barrier layer and the heat-sealable resin layer.

13. The exterior packaging material for an electricity storage device according to claim 12, wherein the adhesive layer is formed from a resin composition containing an acid-modified polypropylene and an elastomer, and further containing at least one of a block polypropylene and a homopolypropylene.

14. The exterior packaging material for an electricity storage device according to claim 13, wherein the elastomer is a binary copolymer elastomer or a ternary copolymer elastomer.

15. The packaging material for an electricity storage device according to any one of claims 1 to 5, further comprising a substrate layer on the side of the barrier layer opposite to the thermally adhesive resin layer side.

16. The exterior packaging material for an electricity storage device according to claim 15, further comprising an adhesive layer between the base layer and the barrier layer.

17. A method for producing an exterior material for an electricity storage device, comprising a step of obtaining a laminate in which at least a barrier layer and a heat-sealable resin layer are laminated in this order, the heat-sealable resin layer having a logarithmic decrement ΔE of 0.075 or less at 150°C in a rigid pendulum measurement.

18. A method for producing an exterior material for an electricity storage device, comprising a step of obtaining a laminate having at least a barrier layer and a heat-sealable resin layer laminated in this order, wherein a sea-island structure is observed in a cross-sectional image obtained using a field emission scanning electron microscope for a cross-section of the heat-sealable resin layer in a direction parallel to the TD and in the thickness direction, wherein when the cross-sectional image is observed over an area of ​​4.50 μm × 6.37 μm at a magnification of 20,000 times, the number of islands having a maximum diameter of 100 nm or more and less than 300 nm is 10 or less, and no island has a maximum diameter of 300 nm or more, and when the cross-sectional image is observed over an area of ​​4.50 μm × 6.37 μm at a magnification of 20,000 times, lamellar crystals are observed in the islands.

19. A method for producing an exterior material for an electricity storage device, comprising a step of obtaining a laminate having at least a barrier layer and a heat-sealable resin layer laminated in this order, wherein the heat-sealable resin layer has a melting peak temperature of 160.0°C or higher, no shoulder peak in the temperature range of 100.0°C or higher and 150.0°C or lower, and a shoulder peak at a temperature above 150.0°C, in a DSC curve obtained by differential scanning calorimetry.

20. An electricity storage device, in which an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte is housed in a packaging body formed from the exterior material for an electricity storage device according to any one of claims 1 to 5.

21. The exterior packaging material for an electricity storage device according to claim 1, wherein the heat-sealable resin layer has a logarithmic decrement ΔE of 0.020 or more at 150° C. in a rigid pendulum measurement.

22. In the absorption spectrum measured on the surface of the heat-sealing resin layer using the ATR measurement mode of FT-IR, a 973 cm -1 The absorption peak intensity P1 at 998 cm originating from the crystalline component -1 3. The exterior packaging material for an electricity storage device according to claim 1 or 2, wherein an intensity ratio X=P2 / P1 of an absorption peak intensity P2 near the vicinity of the absorption peak intensity P1 is 0.830 or less.

23. An exterior material for an electricity storage device as described in claim 5, wherein the heat-fusible resin layer has a melting peak temperature of 160.0°C or higher and 180°C or lower, no shoulder peak in the temperature range of 100.0°C or higher and 150.0°C or lower, and a shoulder peak at a temperature range from above 150.0°C to the melting peak, in a DSC curve obtained by differential scanning calorimetry.

24. The exterior packaging material for an electricity storage device according to claim 1, wherein the heat-sealable resin layer has a logarithmic decrement ΔE of 0.060 or more and 0.073 or less at 150° C. in a rigid pendulum measurement.

25. An exterior material for an electricity storage device as described in claim 5, in which, in a DSC curve obtained by differential scanning calorimetry, the heat-fusible resin layer has a melting peak temperature of 162.0°C or higher, no shoulder peak in the temperature range of 120.0°C or higher and 155.0°C or lower, and a shoulder peak at a temperature above 155.0°C.

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