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

Abstract

This exterior material for a power storage device is formed from a laminate comprising, in order from the outside, at least a base material layer, a barrier layer, and a heat-fusible resin layer, the base material layer including a polyamide resin layer, and the polyamide resin layer having a number average molecular weight (Mn) of 14,500-16,000, and a dispersity (Mw / Mn) of 3.6 or less.

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] As described above, when an exterior material for an electricity storage device is used in an electricity storage device, the exterior material for an electricity storage device is cold-formed to form recesses for accommodating electricity storage device elements, and therefore the exterior material for an electricity storage device is required to have excellent formability.

[0008] One way to improve the formability of packaging materials for electricity storage devices is to use polyamide for the substrate layer, which has the advantage of being more formable than polyester and other materials.

[0009] In recent years, packaging materials for power storage devices used in, for example, on-board lithium-ion batteries have been required to have even better formability in order to increase the capacity of the batteries.

[0010] As a result of investigations, the inventors of the present disclosure have discovered a new problem in that conventional packaging materials for electricity storage devices that use polyamide as a base layer cannot adequately meet such high demands.

[0011] Under these circumstances, a primary object of the present disclosure is to provide an electrical storage device packaging material that is composed of a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-sealable resin layer, and that has excellent formability. Another object of the present disclosure is to provide a method for manufacturing the electrical storage device packaging material and an electrical storage device that uses the electrical storage device packaging material.

[0012] The inventors of the present disclosure have conducted extensive research to solve the above-mentioned problems, and as a result, have found that in a packaging material for an electricity storage device composed of a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-sealable resin layer, by using a polyamide resin layer as the base material layer and adjusting the number average molecular weight and dispersity of the polyamide resin layer to fall within predetermined ranges, the packaging material for an electricity storage device can exhibit excellent formability.

[0013] The present disclosure has been completed based on such novel findings and through further investigation. That is, the present disclosure provides the following aspects of the invention: An exterior packaging material for an electricity storage device, comprising a laminate including, in order from the outside, at least a substrate layer, a barrier layer, and a heat-sealable resin layer, the substrate layer including a polyamide resin layer, the polyamide resin layer having a number average molecular weight (Mn) of 14,500 or more and 16,000 or less, and a polydispersity (Mw / Mn) of 3.6 or less.

[0014] According to the present disclosure, it is possible to provide an electrical storage device packaging material that is composed of a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-sealable resin layer, and that can exhibit excellent formability. Furthermore, the electrical storage device packaging material of the present disclosure also has excellent molding stability, and therefore can exhibit the effect of low rates of pinhole and crack occurrence in the barrier layer (NG rate) when molding a large number of electrical storage device packaging materials. Furthermore, according to the present disclosure, it is also possible to provide a manufacturing method for the electrical storage device packaging material and an electrical storage device using the electrical storage device packaging material.

[0015] 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.

[0016] The electrical storage device packaging material of the present disclosure is composed of a laminate including, from the outside in, at least a substrate layer, a barrier layer, and a heat-sealable resin layer, the substrate layer including a polyamide resin layer, the polyamide resin layer having a number average molecular weight (Mn) of 14,500 or more and 16,000 or less, and a polydispersity (Mw / Mn) of 3.6 or less. The electrical storage device packaging material of the present disclosure having such a configuration can exhibit excellent formability. Furthermore, since the electrical storage device packaging material of the present disclosure also has excellent molding stability, it can also exhibit the effect of a low rate of pinholes and cracks occurring in the barrier layer (NG rate) when molding a large number of electrical storage device packaging materials.

[0017] The exterior packaging material for an electricity storage device of the present disclosure will be described in detail below. Note that in this 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 more and 15 mm or less. In the numerical ranges described in stages in this 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 this disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

[0018] 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.

[0019] 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.

[0020] 1. Laminated Structure of the Electricity Storage Device Exterior Material As shown in FIG. 1 , for example, the electricity storage device exterior material 10 of the present disclosure is composed of a laminate including a base material layer 1, a barrier layer 3, and a heat-sealable resin layer 4 in this order. In the electricity storage device exterior material 10, the base material layer 1 is the outermost layer, and the heat-sealable resin layer 4 is the innermost layer. When assembling an electricity storage device using the 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 peripheries are heat-sealed to form a space, in which the electricity storage device element is housed. In the laminate constituting the electricity storage device exterior material 10 of the present disclosure, with the barrier layer 3 as the reference, the heat-sealable resin layer 4 side is on the inner side relative to the barrier layer 3, and the base material layer 1 side is on the outer side relative to the barrier layer 3.

[0021] 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 outer side of the base material layer 1 (the side opposite to the heat-sealable resin layer 4 side), if necessary.

[0022] 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 210 μm or less, preferably about 190 μm or less, about 180 μm or less, about 155 μm or less, and about 120 μm or less. 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, and about 60 μm or more. Further, preferred ranges of the laminate constituting the exterior packaging material 10 for electricity storage devices include, for example, about 35 to 210 μm, about 35 to 190 μm, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 45 to 210 μm, about 45 to 190 μm, about 45 to 180 μm, about 45 to 155 μm, about 45 to 120 μm, about 60 to 210 μm, about 60 to 190 μm, about 60 to 180 μm, about 60 to 155 μm, and about 60 to 120 μm. In particular, when making the electricity storage device lightweight and thin, about 60 to 155 μm is preferred, and when improving formability, about 155 to 190 μm is preferred.

[0023] In the electrical storage device packaging material 10, the ratio of the total thickness of the base material layer 1, the adhesive layer 2 (which is provided as needed), the barrier layer 3, the adhesive layer 5 (which is provided as needed), the heat-sealable resin layer 4, and the surface coating layer 6 (which is provided as needed) 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, the adhesive layer 2, the barrier layer 3, the adhesive layer 5, and the heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the 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.

[0024] 2. Layers forming the packaging material for an electricity storage device [Substrate layer 1] In the present disclosure, the substrate layer 1 is a layer provided for the purpose of exhibiting the function as a substrate of the packaging material for an electricity storage device, etc. The substrate layer 1 is located on the outer layer side of the packaging material for an electricity storage device.

[0025] In the present disclosure, the substrate layer 1 is characterized by including a polyamide resin layer having a number average molecular weight (Mn) of 14,500 or more and 16,000 or less and a polydispersity (Mw / Mn) of 3.6 or less. A polyamide resin layer having such a number average molecular weight and polydispersity can be evaluated as having excellent moldability among polyamide resins. As described below, in order to adjust the number average molecular weight and polydispersity of the polyamide resin layer, it is important to adjust the number average molecular weight and polydispersity of the polyamide film before forming the polyamide resin layer, as well as the thermal history (heating time, heating temperature, etc.) applied to the polyamide resin layer in the manufacturing process of the exterior material for an electricity storage device of the present disclosure, to prevent the molecular weight of the polyamide from falling outside the above range or the polydispersity of the polyamide from increasing. Even if a polyamide film having a number average molecular weight (Mn) of 14,500 or more and 16,000 or less and a dispersity (Mw / Mn) of 3.6 or less is used for the polyamide resin layer, the number average molecular weight and dispersity of the polyamide resin layer may change during the manufacturing process of the exterior material for an electricity storage device, and the resulting polyamide resin layer may not satisfy the above ranges.

[0026] (Measurement of number average molecular weight and dispersity) <Pretreatment> The substrate layer of the electrical storage device packaging material is peeled off to obtain a polyethylene terephthalate film layer / adhesive layer / polyamide film layer. An incision is made in the polyethylene terephthalate film, and a 5% weight concentration aqueous hydrochloric acid solution is dripped into the incision to dissolve the adhesive layer. After confirming dissolution of the adhesive layer, the polyethylene terephthalate layer is peeled off to obtain a polyamide film. The polyamide film is dissolved by immersing it in a 0.01 mol / L HFIP (hexafluoroisopropanol) solution containing trifluoroacetic acid Na salt. Next, the obtained solution is pressure filtered through a membrane filter with a filter pore size of 0.45 μm. By the above pretreatment, a measurement sample was prepared by dissolving it in a solvent (HFIP solution containing 0.01 mol / L sodium trifluoroacetate), and a differential molecular weight distribution curve was obtained using high-temperature gel permeation chromatography (HLC-8420GPC, manufactured by Tosoh Technosystems Corporation), and the number average molecular weight (Mn) and dispersity (Mw / Mn) were measured and calculated.

[0027] <Measurement Conditions> The measurement conditions for gel permeation chromatography are as follows: sample injection volume 300 μL, guard column HFIP-G8B, two HFIP-806M columns, column temperature 40°C, mobile phase HFIP solution containing 0.01 mol / L trifluoroacetic acid sodium salt, flow rate 0.8 mL / min, detector differential refractive index detector, molecular weight calibration in polymethyl methacrylate equivalent.

[0028] From the viewpoint of more suitably exerting the effects of the present invention, the number average molecular weight (Mn) of the polyamide resin layer is preferably about 14,500 or more, more preferably about 15,000 or more, and preferably about 16,000 or less, and preferred ranges include about 14,500 to 16,000 and about 15,000 to 16,000.

[0029] Furthermore, from the viewpoint of more suitably exerting the effects of the present invention, the polyamide resin layer preferably has a polydispersity (Mw / Mn) of 3.8 or less, more preferably 3.7 or less, and even more preferably 3.6 or less. Preferred ranges include about 1 to 3.8, about 1 to 3.7, and about 1 to 3.6.

[0030] In order to adjust the number average molecular weight and dispersity of the polyamide resin layer within the above ranges, it is important to adjust the number average molecular weight and dispersity of the polyamide film before forming the polyamide resin layer, as well as the thermal history (heating time, heating temperature, etc.) applied to the polyamide resin layer in the manufacturing process of the electrical storage device packaging material of the present disclosure, to prevent the molecular weight of the polyamide from falling outside the above ranges or the dispersity of the polyamide from increasing. Even if a polyamide film having a number average molecular weight (Mn) of 14,500 or more and a dispersity (Mw / Mn) of 3.6 or less is used for the polyamide resin layer, the number average molecular weight and dispersity of the polyamide resin layer may change in the manufacturing process of the electrical storage device packaging material, resulting in a product that does not satisfy the above ranges. Examples of adjustment of the thermal history in the manufacturing process of the electrical storage device packaging material of the present disclosure include adjustment of the heating temperature and heating time applied to the polyamide resin layer in the step of forming a substrate layer including a polyamide resin layer, the step of laminating the substrate layer and the barrier layer, the step of further laminating the laminate of the substrate layer and the barrier layer with a heat-sealable resin layer, the step of aging the electrical storage device packaging material, etc. For example, in the step of laminating the substrate layer and the barrier layer, it is preferable to suppress the temperature during lamination and suppress the thermal history applied to the polyamide resin layer, and in the step of aging the electrical storage device packaging material, it is preferable to suppress the amount of heat applied during aging.

[0031] In the present disclosure, the polyamide resin layer refers to a resin layer containing polyamide as a main component. Here, the term "main component" means that the polyamide content of the resin components contained in the polyamide resin layer 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.

[0032] Specific examples of polyamides constituting the polyamide resin layer include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid, 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. These polyamides may be used alone or in combination of two or more.

[0033] In the present disclosure, for the purpose of preventing the number average molecular weight and dispersity from falling outside the above ranges due to the thermal history applied to the polyamide resin layer, it is preferable that the polyamide resin layer contains nylon 6 and polyamide MXD6, and it is even more preferable that the polyamide resin layer contains nylon 6 and polyamide MXD6 as main components (the total content of nylon 6 and polyamide MXD6 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).

[0034] Furthermore, from the viewpoint of more suitably exhibiting the effects of the present invention, the polyamide resin layer has an amide-derived 3200 cm -1 From 3400 cm -1 "Peak intensity in the range of 680 cm due to aromatic rings" -1 From 700cm-1 The ratio of the "peak intensity of 680 cm due to aromatic rings" -1 From 700cm -1 "Peak intensity of amide-derived 3200 cm -1 From 3400 cm -1 The "peak intensity in the range of" is preferably 0.26 or more, more preferably 0.27 or more, and is preferably 0.70 or less, more preferably 0.60 or less, and even more preferably 0.55 or less, with preferred ranges including 0.26 to 0.70, 0.26 to 0.60, 0.26 to 0.55, 0.27 to 0.70, 0.27 to 0.60, and 0.27 to 0.55. For example, when the polyamide resin layer contains nylon 6 and polyamide MXD6, this ratio serves as a measure of the abundance ratio of nylon 6 and polyamide MXD6. The IR spectrum obtained by infrared spectroscopy of the polyamide resin layer is measured by the following method.

[0035] (Measurement by Infrared Spectroscopy) An IR spectrum of the polyamide resin layer is obtained by infrared spectroscopy under the following measurement conditions. From the obtained IR spectrum, an "amide-derived 3200 cm -1 From 3400 cm -1 "Peak intensity in the range of 680 cm due to aromatic rings" -1 From 700cm -1 The ratio of the peak intensity of the peaks is calculated.

[0036] <Measurement Conditions> The polyamide resin layer is cut into a 100 mm x 100 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-IR under an environment of a temperature of 25°C and a relative humidity of 50%. From the obtained absorption spectrum, it is found that the 3200 cm -1 From 3400 cm -1 and the peak intensity P in the range of 680 cm -1 From 700cm -1 The peak intensity Q of the peak is measured, and the intensity ratio X of the peak intensity Q to the peak intensity P is calculated as Q / P. Method: Macro ATR method Wavenumber resolution: 8 cm -1Number of integrations: 32 times Detector: DTGS detector ATR prism: Ge Incident angle: 45°

[0037] In the present disclosure, the base layer 1 may be composed of only a polyamide resin layer, or may further include a resin layer different from the polyamide resin layer. The polyamide resin layer included in the base layer 1 may be a single layer or two or more layers.

[0038] The resin forming the resin layer different from the polyamide resin layer is not particularly limited as long as it has the function as a substrate, that is, at least insulating properties.

[0039] Examples of resins that form a resin layer different from the polyamide resin layer include polyester, 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 be a copolymer of these resins or a modified version of the copolymer. Furthermore, it may also be a mixture of these resins. Among these, polyester is preferred.

[0040] The resin layer different from the polyamide resin layer preferably contains these resins as the main component, and more preferably contains polyester as the main component. Here, "main component" means that the content of the resin component contained in the resin layer different from the polyamide resin layer 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 resin layer different from the polyamide resin layer contains polyester as the main component" means that the content of polyester among the resin components contained in the resin layer different from the polyamide resin layer 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.

[0041] 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.

[0042] 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.

[0043] The polyamide resin layer is preferably made of a stretched polyamide film, more preferably a biaxially stretched polyamide film. When the base layer 1 contains a polyester resin layer as a resin layer different from the polyamide resin layer, the polyester resin layer is preferably made of a stretched polyester film, more preferably a biaxially stretched polyester film.

[0044] 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 polyamide film, and a laminate of two or more polyamide films, and preferably a laminate of a stretched polyamide film and a stretched polyester film, or a laminate of two or more stretched polyamide films. For example, when the base layer 1 is a laminate of two resin films, a laminate of a polyamide film and a polyamide film, or a laminate of a polyester film and a polyamide film, is preferred, and a laminate of a polyethylene terephthalate film and a polyamide film is more preferred. Furthermore, because polyester is less likely to discolor when an electrolytic solution adheres to its surface, for example, when the base layer 1 is a laminate of two or more resin films, it is preferred that the polyester film be located on the side of the base layer 1 opposite the barrier layer 3. In the laminate of polyester film and polyamide film, preferred ranges of the thickness of the polyester 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 about 18 to 28 μm. , about 18 to 23 μm, and preferred ranges for the thickness of the polyamide 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.

[0045] 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.

[0046] Furthermore, additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents 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.

[0047] 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.

[0048] 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

[0049] 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.

[0050] The substrate layer 1 can be formed, for example, from a resin film. When the substrate layer 1 is formed from 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 from 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 biaxially stretched films include sequential biaxial stretching, inflation, and simultaneous biaxial stretching. Examples of methods for applying the resin include roll coating, gravure coating, and extrusion coating.

[0051] The thickness of the substrate layer 1 is not particularly limited as long as it functions as a substrate, but examples thereof include about 3 μm or more, preferably about 10 μm or more. Furthermore, examples of the thickness of the substrate layer 1 include about 50 μm or less, preferably about 35 μm or less, about 11 μm or less, and about 8 μm or less. Preferred thickness ranges for the substrate layer 1 include about 3 to 50 μm, about 3 to 35 μm, about 3 to 11 μm, about 3 to 8 μm, about 10 to 50 μm, about 10 to 35 μm, and about 10 to 11 μm. In particular, when making an electricity storage device lighter and thinner, about 3 to 35 μm, about 3 to 11 μm, or about 3 to 8 μm is 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 each resin film constituting each layer is not particularly limited, but may be, for example, about 2 μm or more, preferably about 10 μm or more, or about 18 μm or more, and may be, for example, about 33 μm or less, preferably about 28 μm or less, about 23 μm or less, about 18 μm or less, about 11 μm or less, or about 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.

[0052] [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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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 %.

[0061] 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.

[0062] [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.

[0063] 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.

[0064] Specific examples of the colorant contained in the colored layer include the same as those exemplified in the section [Adhesive layer 2].

[0065] [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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] Specific examples of austenitic stainless steels that form the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

[0071] 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 50 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 50 μm, approximately 10 to 40 μm, approximately 10 to 35 μm, approximately 20 to 85 μm, approximately 20 to 50 μm, approximately 20 to 40 μm, approximately 20 to 35 μm, approximately 25 to 85 μm, approximately 25 to 50 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075]

[0076]

[0077]

[0078]

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] The composition of the corrosion-resistant film can be analyzed by, for example, time-of-flight secondary ion mass spectrometry.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] [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.

[0088] The resin constituting the heat-sealable resin layer 4 is not particularly limited as long as it is heat-sealable, 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-sealable 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-sealable resin layer 4 is analyzed by infrared spectroscopy, a peak derived from maleic anhydride is preferably detected. For example, when 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 -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.

[0089] The heat-sealable resin layer 4 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.

[0090] Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. Among these, polypropylene is preferred. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. These polyolefin resins may be used alone or in combination of two or more.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] Furthermore, the thermally adhesive resin layer 4 may contain a lubricant or the like, if 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.

[0098] 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.

[0099] 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.

[0100] When a lubricant is present on the surface of the heat-sealable resin layer 4, the amount of the lubricant is not particularly limited. However, from the viewpoint of improving the formability of the exterior material for an electrical storage device, the amount of the lubricant is preferably about 1 mg / m 2 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

[0101] 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 lubricant 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.

[0102] 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.

[0103] 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.

[0104] [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.

[0105] The adhesive layer 5 is formed of a resin that can bond 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] The adhesive layer 5 may contain a modifier having a carbodiimide group.

[0123] 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.

[0124] 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.

[0125] [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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] The surface coating layer 6 may contain additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents, 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.

[0130] 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.

[0131] Specific examples of additives include talc, silica, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, high-melting-point nylon, acrylate resin, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, 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. The additives may also be subjected to various surface treatments, such as insulation treatment and high-dispersibility treatment.

[0132] 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.

[0133] 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.

[0134] 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

[0135] 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.

[0136] 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.

[0137] 3. Manufacturing Method of the Exterior Material for an Electrical Storage Device The manufacturing method of the exterior material for an electrical storage device is not particularly limited, as long as a laminate in which the layers included in the exterior material for an electrical storage device of the present disclosure are laminated can be obtained, and an example of such a method includes a step of laminating at least the base material layer 1, the barrier layer 3, and the heat-sealable resin layer 4 in this order.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] The packaging material for an electricity storage device according to the present disclosure is used in a package for hermetically housing an electricity storage device element such as a positive electrode, a negative electrode, an electrolyte, etc. 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 packaging material for an electricity storage device according to the present disclosure.

[0144] 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 portions of the overlapped electrical storage device exterior materials. Alternatively, as shown in the example of Fig. 5, one electrical storage device exterior material may be folded over and overlapped, and the peripheral portions may be heat-sealed to form a package. When folding and overlapping, as shown in the example of Fig. 5, the sides other than the folded side may be heat-sealed to form a package with a three-sided seal, or the material may be folded over to form a flange and sealed on all four sides. Alternatively, the electrical storage device exterior material may be wrapped around an electrical storage device element, the heat-sealable resin layers may be sealed together to form a heat-sealed portion, and a lid or the like may be positioned to close the openings at both ends, and the lid may be heat-sealed to the electrical storage device exterior material wrapped around the electrical storage device element to seal it. The lid may be formed, for example, from a resin molded product, a metal molded product, an electrical storage device exterior material, or the like. 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.

[0145] 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.

[0146] 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.

[0147] Examples 1-2 and Comparative Examples 1-3 Production of Exterior Materials for Electricity Storage Devices As the substrate layer, a laminate was prepared in which a polyethylene terephthalate film (thickness 12 μm) and a polyamide film A-B (thickness 15 μm) shown in Table 1 were bonded together with an adhesive (a two-component curing urethane adhesive (a polyester polyol and an aromatic isocyanate compound)) (thickness of the adhesive after curing was 3 μm). Details of the polyamide films A-B will be described later. As the barrier layer, an aluminum alloy foil (JIS H4160:1994 A8021H-O, thickness 40 μm) was prepared. Next, the polyamide film side of the substrate layer and the barrier layer were bonded together by a dry lamination method using the two-component curing urethane adhesive (a polyester polyol and an alicyclic isocyanate compound), to produce a laminate in which the substrate layer / adhesive layer / barrier layer were laminated in that order.

[0148] Next, maleic anhydride-modified polypropylene as an adhesive layer and random polypropylene as a heat-sealable resin layer were melt-extruded onto the barrier layer of each of the laminates obtained above, thereby laminating an adhesive layer (thickness 40 μm) / heat-sealable resin layer (thickness 40 μm) on the barrier layer, thereby obtaining an exterior packaging material for an electricity storage device in which base material layer (PET / adhesive layer / ONy) / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0149] (Manufacturing conditions A to C) The manufacturing conditions A to C of the electrical storage device packaging material listed in Table 1 each have a different thermal history in the manufacturing process of the electrical storage device packaging material, and the thermal history is as follows. Manufacturing condition A: manufactured under thermal conditions at or below the low-temperature peak temperature (60 to 90°C) of the DSC curve of the polyamide film obtained with a differential scanning calorimeter and lower than condition C. Manufacturing condition B: manufactured under thermal conditions higher than the low-temperature peak temperature of the DSC curve of the polyamide film obtained with a differential scanning calorimeter. Manufacturing condition C: manufactured under thermal conditions at or below the low-temperature peak temperature of the DSC curve of the polyamide film obtained with a differential scanning calorimeter and higher than condition A. <Measurement of low-temperature peak temperature> The low-temperature peak temperature was measured using a differential scanning calorimeter (DSC, Shimadzu Corporation's DSC-60A Plus differential scanning calorimeter). Specifically, the polyamide film was heated from 0°C to 250°C at a heating rate of 10°C / min by differential scanning calorimetry (DSC) according to the procedure of JIS K7121:2012 (Method for measuring transition temperatures of plastics (JIS K7121:1987 Supplement 1)), and the low-temperature peak temperature (°C) was measured. The flow rate of nitrogen gas was 50 ml / min. The low-temperature peak temperature (°C) was determined according to the above procedure.

[0150] (Polyamide film) (Composition) Polyamide film A: number average molecular weight Mn = 15,500 Polyamide film B: number average molecular weight Mn = 16,000

[0151] (Measurement of Number Average Molecular Weight and Dispersity) For each of the polyamide films A and B contained in the electrical storage device packaging material, high-temperature gel permeation chromatography (HLC-8420GPC manufactured by Tosoh Technosystems Corporation) was performed under the following pretreatment and measurement conditions. The concentration fraction of each molecular weight was sequentially integrated with each molecular weight (logarithmic value) on the horizontal axis to obtain an integrated molecular weight distribution curve. A differential molecular weight distribution curve was obtained by calculating the differential value of the curve at each molecular weight, and the number average molecular weight (Mn) and dispersity (Mw / Mn) were measured and calculated. The results are shown in Table 1. <Pretreatment> The substrate layer of the electrical storage device packaging material was peeled off to obtain a polyethylene terephthalate film layer / adhesive layer / polyamide film layer. An incision was made in the polyethylene terephthalate film, and a 5% by weight aqueous hydrochloric acid solution was dripped into the incision to dissolve the adhesive layer. After confirming that the adhesive layer had dissolved, the polyethylene terephthalate layer was peeled off to obtain a polyamide film. Polyamide films A and B were each dissolved by immersing them in a 0.01 mol / L hexafluoroisopropanol (HFIP) solution containing sodium trifluoroacetate. The resulting solution was then pressure-filtered through a 0.45 μm membrane filter. The measurement sample was dissolved in a solvent (0.01 mol / L HFIP solution containing sodium trifluoroacetate) using the pretreatment described above. A differential molecular weight distribution curve was obtained using high-temperature gel permeation chromatography (HLC-8420GPC, manufactured by Tosoh Technosystems Corporation), and the number-average molecular weight (Mn) and polydispersity (Mw / Mn) were measured and calculated.

[0152] <Measurement Conditions> The measurement conditions for gel permeation chromatography are as follows: sample injection volume 300 μL, guard column HFIP-G8B, two HFIP-806M columns, column temperature 40°C, mobile phase HFIP solution containing 0.01 mol / L trifluoroacetic acid sodium salt, flow rate 0.8 mL / min, detector differential refractive index detector, molecular weight calibration in polymethyl methacrylate equivalent.

[0153] (Measurement by infrared spectroscopy) An IR spectrum of the polyamide film A-B was obtained by infrared spectroscopy under the following measurement conditions. From the obtained IR spectrum, an "amide-derived 3200 cm -1 From 3400 cm -1 "Peak intensity in the range of 680 cm due to aromatic rings" -1 From 700cm -1 The ratio of the peak intensity of the peaks was calculated. The results are shown in Table 1.

[0154] <Measurement Conditions> Polyamide films A and B were each cut into a 100 mm x 100 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 a Nicolet iS10 FT-IR manufactured by Thermo Fisher Scientific Co., Ltd. From the obtained absorption spectrum, it was found that the 3200 cm -1 From 3400 cm -1 and the peak intensity P in the range of 680 cm -1 From 700cm -1 The peak intensity Q of each peak was measured, and the intensity ratio X of the peak intensity Q to the peak intensity P was calculated as X = Q / P. Method: Macro ATR method Wavenumber resolution: 8 cm -1 Number of integrations: 32 times Detector: DTGS detector ATR prism: Ge Incident angle: 45°

[0155] (Evaluation of formability) Each electrical storage device exterior material was cut into a rectangle with a length (MD direction) of 90 mm and a width (TD direction) of 150 mm to prepare a test sample. The MD of the electrical storage device exterior material corresponded to the rolling direction (RD) of the aluminum alloy foil, and the TD of the electrical storage device exterior material corresponded to the TD of the aluminum alloy foil. This sample was placed in a 25°C environment in a rectangular molding die (female die, the surface of which had a maximum height roughness (nominal value of Rz) of 3.2 μm as specified in Table 2 of the surface roughness standard for comparison in JIS B 0659-1:2002, Annex 1 (Reference), corner R2.0 mm, ridge R1.0 mm) with a bore of 31.6 mm (MD) x 54.5 mm (TD) and a corresponding molding die (male die, the surface of the ridgeline had a maximum height roughness (nominal value of Rz) of 1.6 μm as specified in Table 2 of the surface roughness standard for comparison in JIS B 0659-1:2002, Annex 1 (Reference), corner R2.0 mm, ridgeline R1.0 mm). The maximum height roughness (nominal Rz value) of the comparative surface roughness standard specimen, as specified in Table 2, is 3.2 μm. Using a corner R of 2.0 mm and a ridge R of 1.0 mm, a pressing pressure (surface pressure) of 0.25 MPa was applied to ten samples, with the forming depth varied in 0.5 mm increments from a forming depth of 0.5 mm. The test samples were placed on a female mold with the heat-fusible resin layer facing the male mold. The clearance between the male and female molds was 0.3 mm. After cold forming, the samples were irradiated with a penlight in a darkroom to check for pinholes or cracks in the aluminum alloy foil. The deepest forming depth at which no pinholes or cracks occurred in the aluminum alloy foil in any of the 10 samples was defined as A mm, and the number of samples at which pinholes or the like occurred in the aluminum alloy foil at the shallowest forming depth was defined as B. The value calculated by the following formula was rounded to two decimal places to determine the limit forming depth of the exterior material for an electricity storage device: Limit forming depth = A mm + (0.5 mm / 10 samples) × (10 samples - B samples).

[0156] Furthermore, for each electrical storage device packaging material, the rate at which pinholes and cracks occurred in the aluminum alloy foil (NG rate) was measured when the packaging material was molded at molding depths of 6.5 mm, 7.0 mm, and 7.5 mm. The NG rate was calculated by molding 10 samples at each molding depth and expressing the rate of samples in which pinholes and cracks occurred in the aluminum alloy foil. The results are shown in Table 1.

[0157]

[0158] As described above, the present disclosure provides the following aspects of the invention. Item 1. A packaging material for an electricity storage device, comprising a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-sealable resin layer, the base material layer including a polyamide resin layer, the polyamide resin layer having a number average molecular weight (Mn) of 14,500 or more and 16,000 or less and a dispersity (Mw / Mn) of 3.6 or less. Item 2. The packaging material for an electricity storage device according to Item 1, wherein the polyamide resin layer has a number average molecular weight (Mn) of 15,000 or more and 16,000 or less. Item 3. The polyamide resin layer is characterized in that it exhibits an "amide-derived 3200 cm" peak in a spectrum obtained by infrared spectroscopy. -1 From 3400 cm -1 "Peak intensity in the range of 680 cm due to aromatic rings" -1 From 700cm -1Item 4. The packaging material for an electricity storage device according to any one of Items 1 to 3, wherein the ratio of "peak intensity at 1 / 2" to "peak intensity at 1 / 2" is 0.26 or more. Item 4. The packaging material for an electricity storage device according to any one of Items 1 to 3, wherein the polyamide resin layer contains nylon 6 and polyamide MXD6. Item 5. The packaging material for an electricity storage device according to any one of Items 1 to 4, further comprising an adhesive layer between the barrier layer and the heat-sealable resin layer. Item 6. The packaging material for an electricity storage device according to any one of Items 1 to 5, further comprising an adhesive layer between the base material layer and the barrier layer. Item 7. A method for producing a packaging material for an electricity storage device, comprising a step of obtaining a laminate comprising at least a base material layer, a barrier layer, and a heat-sealable resin layer stacked in this order from the outside, wherein the base material layer contains a polyamide resin layer, and the polyamide resin layer has a number average molecular weight (Mn) of 14,500 or more and 16,000 or less, and a polydispersity (Mw / Mn) of 3.6 or less. Item 8. Item 7. An electricity storage device, comprising an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte, housed in a package formed from the exterior packaging material for an electricity storage device according to any one of Items 1 to 6.

[0159] REFERENCE SIGNS LIST 1 base material 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

Claims

1. An exterior material for an electricity storage device, comprising a laminate including, in order from the outside, at least a substrate layer, a barrier layer, and a heat-sealable resin layer, the substrate layer including a polyamide resin layer, the polyamide resin layer having a number average molecular weight (Mn) of 14,500 or more and 16,000 or less, and a polydispersity (Mw / Mn) of 3.6 or less.

2. The packaging material for an electricity storage device according to claim 1, wherein the polyamide resin layer has a number average molecular weight (Mn) of 15,000 or more and 16,000 or less.

3. The polyamide resin layer has a peak at 3200 cm derived from an amide in a spectrum obtained by infrared spectroscopy. -1 From 3400 cm -1 "Peak intensity in the range of 680 cm due to aromatic rings" -1 From 700cm -1 The packaging material for an electricity storage device according to claim 1 or 2, wherein a ratio of the peak intensity of the peak at which the electrical storage device is heated to 1000 W / m is 0.26 or more.

4. The packaging material for an electricity storage device according to claim 1 or 2, wherein the polyamide resin layer contains nylon 6 and polyamide MXD6.

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

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

7. A method for producing an exterior material for an electrical storage device, comprising a step of obtaining a laminate in which, from the outside, a base layer, a barrier layer, and a heat-sealable resin layer are laminated in this order, the base layer including a polyamide resin layer, and the polyamide resin layer has a number average molecular weight (Mn) of 14,500 or more and 16,000 or less, and a polydispersity (Mw / Mn) of 3.6 or less.

8. 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 package formed from the exterior packaging material for an electricity storage device according to claim 1 or 2.

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