JP6870777B2 - Exterior materials for power storage devices, their manufacturing methods, and power storage devices - Google Patents

Description

The present disclosure relates to an exterior material for a power storage device, a method for manufacturing the same, and a power storage device.

Conventionally, various types of power storage devices have been developed, but in all power storage devices, an exterior material is an indispensable member for sealing a power storage device element such as an electrode or an electrolyte. Conventionally, a metal exterior material has been widely used as an exterior material for a power storage device.

On the other hand, in recent years, with the improvement of high performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., various shapes are required for power storage devices, and thinning and weight reduction are required. However, the metal exterior material for a power storage device, which has been widely used in the past, has a drawback that it is difficult to keep up with the diversification of shapes and there is a limit to weight reduction.

Therefore, in recent years, as an exterior material for a power storage device that can be easily processed into various shapes and can be made thinner and lighter, it is in the form of a film in which a base material layer / barrier layer / thermosetting resin layer is sequentially laminated. Laminates have been proposed (see, for example, Patent Document 1).

In such an exterior material for a power storage device, a recess is generally formed by cold molding, and a storage device element such as an electrode or an electrolytic solution is arranged in the space formed by the recess to form a thermosetting resin. By heat-sealing the layers, a power storage device in which the power storage device element is housed inside the exterior material for the power storage device can be obtained.

Japanese Unexamined Patent Publication No. 2008-287971

The exterior material for a power storage device composed of the film-like laminate described above is softer than the metal exterior material and is easily scratched on the surface. Therefore, it is desirable to improve the scratch resistance. As a method for improving the scratch resistance of the exterior material for a power storage device, it is conceivable to provide a hard surface coating layer containing inorganic particles such as silica particles on the outer side of the base material layer.

As a method for forming such a hard surface coating layer, a method of printing a resin composition containing silica particles and a resin by using a gravure printing method or the like can be considered. However, as a result of studies by the inventors of the present disclosure, it has been found that when a resin composition containing silica particles is printed to form a thin surface coating layer of 10 μm or less, printing unevenness is likely to occur. .. Specifically, when the surface state of the surface coating layer after printing was observed with a microscope, it was found that traces due to the shape of the printing plate were unevenly formed on the surface of the surface coating layer.

Under such circumstances, the present disclosure mainly provides an exterior material for a power storage device, which exhibits excellent scratch resistance due to a surface coating layer containing silica particles and has high uniformity of the surface state of the surface coating layer. Purpose. Due to the high uniformity of the surface state of the surface coating layer, uniform printing is possible on the surface of the exterior material for the power storage device, and the appearance is beautiful.

The inventors of the present disclosure have made diligent studies to solve the above problems. As a result, a surface coating layer having an average thickness of 10 μm or less is formed on the outside of the exterior material for the power storage device separately for the first surface coating layer and the second surface coating layer, and the first surface coating layer is made of silica. When the particles and the resin are blended and the inorganic particles different from the silica particles and the resin are blended in the second surface coating layer located below the first surface coating layer, the surface coating layer containing the silica particles is excellent. It has been found that the uniformity of the surface state of the surface coating layer is enhanced while exhibiting scratch resistance.

This disclosure has been completed by further studies based on these findings. That is, the present disclosure provides the inventions of the following aspects.
It is composed of a laminate having at least a surface coating layer, a base material layer, a barrier layer, an adhesive layer, and a thermosetting resin layer in this order from the outside.
The surface coating layer includes a first surface coating layer and a second surface coating layer in this order from the outside.
The first surface coating layer contains silica particles and a resin, and contains silica particles and a resin.
The second surface coating layer contains inorganic particles and a resin different from the silica particles, and contains resin.
An exterior material for a power storage device, wherein the surface coating layer has an average film thickness of 10 μm or less.

According to the present disclosure, it is possible to provide an exterior material for a power storage device, which exhibits excellent scratch resistance due to a surface coating layer containing silica particles and has high uniformity of the surface state of the surface coating layer. Further, according to the present disclosure, it is also possible to provide a method for manufacturing the exterior material for the power storage device and a power storage device using the exterior material for the power storage device.

It is a schematic diagram which shows an example of the cross-sectional structure of the exterior material for a power storage device of this disclosure. It is a schematic diagram which shows an example of the cross-sectional structure of the exterior material for a power storage device of this disclosure. It is a schematic diagram which shows an example of the cross-sectional structure of the exterior material for a power storage device of this disclosure. It is a micrograph of the surface of the surface coating layer of the exterior material for a power storage device obtained in Example 1 (the photograph on the left is a photograph taken at a magnification of 10 times, and the photograph on the right is a photograph taken at a magnification of 20 times. Is). It is a micrograph of the surface of the surface coating layer of the exterior material for a power storage device obtained in Example 2 (the photograph on the left is a photograph taken at a magnification of 10 times, and the photograph on the right is a photograph taken at a magnification of 20 times. Is). It is a micrograph of the surface of the surface coating layer of the exterior material for a power storage device obtained in Comparative Example 1 (the photograph on the left is a photograph taken at a magnification of 10 times, and the photograph on the right is a photograph taken at a magnification of 20 times. Is). It is a micrograph of the surface of the surface coating layer of the exterior material for a power storage device obtained in Comparative Example 2 (the photograph on the left is a photograph taken at a magnification of 10 times, and the photograph on the right is a photograph taken at a magnification of 20 times. Is). It is a figure which shows typically the appearance of observing the cross section in the thickness direction of the 1st surface coating layer and the 2nd surface coating layer of the exterior material for a power storage device of this disclosure with a scanning electron microscope.

The exterior material for a power storage device of the present disclosure is composed of a laminate including a surface coating layer, a base material layer, a barrier layer, and a heat-sealing resin layer in this order from the outside. A first surface coating layer and a second surface coating layer are provided in this order from the outside, the first surface coating layer contains silica particles and a resin, and the second surface coating layer is a silica particle. It contains different inorganic particles and a resin, and the average thickness of the surface coating layer is 10 μm or less. The exterior material for a power storage device of the present disclosure is characterized in that, by having the above-mentioned structure, the surface coating layer containing silica particles exhibits excellent scratch resistance, and the surface state of the surface coating layer is highly uniform. It will be demonstrated.

Hereinafter, the exterior material for the power storage device of the present disclosure will be described in detail. In this specification, the numerical range indicated by "~" means "greater than or equal to" and "less than or equal to". For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less.

1. 1. Laminated structure of exterior material for power storage device The exterior material 10 for power storage device of the present disclosure has at least a first surface coating layer 7, a second surface coating layer 6, and a base material layer 1, as shown in FIGS. 1 to 3, for example. , A barrier layer 3, and a laminate including a thermosetting resin layer 4. In the exterior material 10 for a power storage device of the present disclosure, the first surface coating layer 7 and the second surface coating layer 6 form a surface coating layer. In the exterior material 10 for a power storage device, the first surface coating layer 7 is the outermost layer, and the thermosetting resin layer 4 is the innermost layer. When assembling a power storage device using the power storage device exterior material 10 and the power storage device element, the peripheral portion is heat-sealed with the thermosetting resin layers 4 of the power storage device exterior material 10 facing each other. The power storage device element is housed in the space formed by.

As shown in FIGS. 2 to 3, for example, the exterior material 10 for a power storage device is used, if necessary, for the purpose of enhancing the adhesiveness between the base material layer 1 and the barrier layer 3 and the like. It may have an adhesive layer 2. Further, for example, as shown in FIG. 3, an adhesive layer 5 is provided between the barrier layer 3 and the thermosetting resin layer 4 as needed for the purpose of enhancing the adhesiveness between the layers. May be.

The thickness of the laminate constituting the exterior material 10 for the power storage device is not particularly limited, but is preferably about 180 μm or less, about 155 μm or less, and about 120 μm or less from the viewpoint of cost reduction, energy density improvement, and the like. Further, the thickness of the laminate constituting the exterior material 10 for the power storage device is preferably about 35 μm or more, about 45 μm or more, and about from the viewpoint of maintaining the function of the exterior material for the power storage device of protecting the power storage device element. 60 μm or more can be mentioned. The preferable range of the thickness of the laminate constituting the exterior material 10 for the power storage device is, for example, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 45 to 180 μm, about 45 to 155 μm, and about 45 to 45. Examples thereof include about 120 μm, about 60 to 180 μm, about 60 to 155 μm, and about 60 to 120 μm, and particularly about 60 to 155 μm is preferable. The thickness of the laminate constituting the exterior material 10 for the power storage device is the average film thickness of the first surface coating layer 7 and the second surface coating layer 6 combined, and the first surface coating layer 7 and the second surface coating layer. It is the sum with the total film thickness of the layers other than 6.

In the power storage device exterior material 10, the first surface coating layer 7, the second surface coating layer 6, the base material layer 1, and if necessary, with respect to the thickness (total thickness) of the laminate constituting the power storage device exterior material 10. The ratio of the total thickness of the adhesive layer 2, the barrier layer 3, the adhesive layer 5 provided as needed, and the thermosetting resin layer 4 is preferably 90% or more, more preferably 95% or more. It is more preferably 98% or more. As a specific example, the exterior material 10 for a power storage device of the present disclosure includes a first surface coating layer 7, a second surface coating layer 6, a base material layer 1, an adhesive layer 2, a barrier layer 3, an adhesive layer 5, and heat. When the fusible resin layer 4 is included, the ratio of the total thickness of each of these layers to the thickness (total thickness) of the laminate constituting the exterior material 10 for the power storage device is preferably 90% or more, more preferably 95. % Or more, more preferably 98% or more. Further, the exterior material 10 for a power storage device of the present disclosure comprises a first surface coating layer 7, a second surface coating layer 6, a base material layer 1, an adhesive layer 2, a barrier layer 3, and a thermosetting resin layer 4. Even in the case of including, the ratio of the total thickness of each of these layers to the thickness (total thickness) of the laminate constituting the exterior material 10 for the power storage device is preferably 90% or more, more preferably 95% or more. More preferably, it can be 98% or more.

2. Each layer forming an exterior material for a power storage device [first surface coating layer 7]
The exterior material 10 for a power storage device of the present disclosure has a first surface coating layer 7 on the outer surface for the purpose of enhancing scratch resistance and the like. The first surface coating layer 7 is a layer located on the outermost layer of the exterior material 10 for a power storage device when the power storage device is assembled using the exterior material 10 for the power storage device.

The first surface coating layer 7 contains silica particles 71 and a resin. That is, the first surface coating layer 7 is formed of a resin composition containing silica particles 71 and a resin. Further, the average film thickness of the first surface coating layer 7 and the second surface coating layer 6 described later is set to 10 μm or less.

The particle size of the silica particles 71 is, for example, about 0.5 nm to 5 μm, preferably about 0.5 to 3 μm, from the viewpoint of preferably achieving both excellent scratch resistance and excellent uniformity of the surface state of the surface coating layer. Can be mentioned.

The average particle size of the silica particles 71 is a median size measured by a laser diffraction / scattering type particle size distribution measuring device.

From the viewpoint of preferably achieving both excellent scratch resistance and excellent uniformity of the surface state of the surface coating layer, the content of the silica particles 71 contained in the first surface coating layer 7 is based on 100 parts by mass of the resin. It is preferably about 0.1 part by mass or more, more preferably about 0.5 part by mass or more, and further preferably about 1.0 part by mass or more. From the same viewpoint, the content of the silica particles 71 contained in the first surface coating layer 7 is preferably about 10.0 parts by mass or less, more preferably about 5.0 parts by mass or less, and further preferably about about. 3.0 parts by mass or less can be mentioned. The preferable range of the content of the silica particles 71 contained in the first surface coating layer 7 is about 0.1 to 10.0 parts by mass, about 0.1 to 5.0 parts by mass, and 0.1 to 3. About 0.0 parts by mass, about 0.5 to 10.0 parts by mass, about 0.5 to 5.0 parts by mass, about 0.5 to 3.0 parts by mass, about 1.0 to 10.0 parts by mass, Examples thereof include about 1.0 to 5.0 parts by mass and about 1.0 to 3.0 parts by mass.

The first surface coating layer 7 further contains organic particles 72 in addition to the silica particles 71, from the viewpoint of preferably achieving both excellent scratch resistance and excellent uniformity of the surface condition of the surface coating layer. Is preferable. Examples of the organic particles 72 include organic particles such as nylon, polyacrylate, polystyrene-based, styrene-acrylic copolymer, polyethylene, benzoguanamine, and crosslinked products thereof. The organic particles 72 contained in the first surface coating layer 7 may be of one type or two or more types.

The particle size of the organic particles 72 is preferably about 5.0 μm or less, more preferably about 3.0 μm or less, from the viewpoint of preferably achieving both excellent scratch resistance and excellent uniformity of the surface state of the surface coating layer. , More preferably about 2.0 μm or less. From the same viewpoint, the particle size of the organic particles 72 is preferably about 0.3 μm or more, more preferably about 0.5 μm or more, still more preferably about 1.0 μm or more. The preferred range of the particle size of the organic particles 72 is about 0.3 to 5.0 μm, about 0.3 to 3.0 μm, about 0.3 to 2.0 μm, about 0.5 to 5.0 μm, and the like. Examples thereof include about 0.5 to 3.0 μm, about 0.5 to 2.0 μm, about 1.0 to 5.0 μm, about 1.0 to 3.0 μm, and about 1.0 to 2.0 μm. The description of the particle size means that among the organic particles 72 contained in the first surface coating layer 7, organic particles having these particle sizes are predominantly contained. Of the organic particles 72 contained in the first surface coating layer 7, the proportion of the organic particles having these particle sizes is preferably 50% or more, more preferably 80% or more, still more preferably 90% or more, and 100%. It may be.

The particle size of the organic particles 72 is a value measured for a cross-sectional image of the scratch-resistant layer 7 in the thickness direction observed using a scanning electron microscope. The particle size of the organic particles 72 is the maximum linear distance connecting the leftmost end in the direction perpendicular to the thickness direction of the particles and the rightmost end in the direction perpendicular to the thickness direction with respect to the particle size observed by the scanning electron microscope. Means the diameter that becomes. The particle size of the organic particles 72 is not the average particle size.

The shape of the organic particles 72 is not particularly limited, and examples thereof include a spherical shape, a fibrous shape, a plate shape, an amorphous shape, and a scaly shape, and a spherical shape is preferable.

When the first surface coating layer 7 contains organic particles 72, the content of the organic particles 72 is 100 mass by mass of the resin, from the viewpoint of preferably achieving both excellent scratch resistance and excellent uniformity of the surface condition of the surface coating layer. With respect to the portion, preferably about 0.01 part by mass or more, more preferably about 0.1 part by mass or more, still more preferably about 0.5 part by mass or more. From the same viewpoint, the content is preferably about 10.0 parts by mass or less, more preferably about 5.0 parts by mass or less, and further preferably about 3.0 parts by mass or less. The preferable range of the content is about 0.01 to 10.0 parts by mass, about 0.01 to 5.0 parts by mass, about 0.01 to 3.0 parts by mass, and 0.1 to 10. About 0 parts by mass, about 0.1 to 5.0 parts by mass, about 0.1 to 3.0 parts by mass, about 0.5 to 10.0 parts by mass, about 0.5 to 5.0 parts by mass, 0 .5 to 3.0 parts by mass.

The average film thickness of the first surface coating layer 7 is not particularly limited as long as the combined average film thickness of the first surface coating layer 7 and the second surface coating layer 6 described later is 10 μm or less, but it has excellent scratch resistance. From the viewpoint of preferably achieving excellent uniformity of the surface state of the surface coating layer, it is preferably about 2.5 μm or less, more preferably about 2.0 μm or less, still more preferably about 1.5 μm or less. From the same viewpoint, the average film thickness of the first surface coating layer 7 is preferably about 0.3 μm or more, more preferably about 0.5 μm or more. The preferred range of the average film thickness of the first surface coating layer 7 is about 0.3 to 2.5 μm, about 0.3 to 2.0 μm, about 0.3 to 1.5 μm, and 0.5 to 2.5 μm. The degree is about 0.5 to 2.0 μm, and about 0.5 to 1.5 μm. The method for measuring the average film thickness of the first surface coating layer 7 is as follows.

<Average film thickness>
The average film thickness of the first surface coating layer 7 and the second surface coating layer 6 of the laminate constituting the exterior material for the power storage device is measured and calculated as follows, respectively. A cross-sectional image of the cross-section in the thickness direction of the laminate constituting the exterior material for the power storage device is acquired using a scanning electron microscope (SEM). Next, with respect to the cross-sectional image, the cross-sectional areas of the first surface coating layer 7 and the second surface coating layer 6 are measured by image analysis, respectively. At this time, the horizontal length of the measurement area of the cross-sectional area (the length in the direction perpendicular to the thickness direction of the laminated body) is 25.4 μm. Next, the average film thickness (μm) of the first surface coating layer 7 and the second surface coating layer 6 is calculated by dividing the obtained area by the horizontal length (25.4 μm). To do. When measuring and calculating the total average film thickness of the first surface coating layer 7 and the second surface coating layer 6, the cross-sectional area of the first surface coating layer 7 and the second surface coating layer 6 in the same measurement area. Is measured at the same time, and the obtained area is divided by the horizontal length (25.4 μm) of the measurement area to obtain an average thickness (μm) of the first surface coating layer 7 and the second surface coating layer 6 combined. ) Is calculated.

The first surface coating layer 7 preferably contains particles having a particle size larger than the average film thickness of the first surface coating layer 7. That is, the first surface coating layer 7 contains silica particles having a particle size larger than the average film thickness of the first surface coating layer 7 as at least a part of the silica particles, and the first surface coating layer 7 having a particle size larger than the average film thickness of the first surface coating layer 7. It is preferable that at least one of organic particles having a large particle size is contained. Further, it is preferable that the second surface coating layer 6 described later contains particles having a particle size larger than the average film thickness of the second surface coating layer 6. That is, in the second surface coating layer 6, the inorganic particles having a particle size larger than the average thickness of the second surface coating layer 6 as at least a part of the inorganic particles and the average thickness of the second surface coating layer 6 are larger than the average thickness of the second surface coating layer 6. It is preferable that at least one of organic particles having a large particle size is contained. For each of the first surface coating layer 7 and the second surface coating layer 6, particles having a particle size larger than the average film thickness of each layer are hereinafter referred to as "large particles". It is more preferable that both the first surface coating layer 7 and the second surface coating layer 6 contain large particles, respectively. The large particles are preferably any of silica particles 71, inorganic particles 61, and organic particles 62 and 72, and preferably organic particles 62 and 72. That is, when at least one layer of the first surface coating layer 7 and the second surface coating layer 6 contains organic particles 62 and 72, the at least one layer of the first surface coating layer 7 and the second surface coating layer 6 Preferably contains organic particles 62 and 72 having a particle size larger than the average thickness of the layer. It is preferable that, for example, about 30 or more large particles of each layer (first surface coating layer 7 and second surface coating layer 6) are contained in a range of 1 mm in width of each layer. The number of large particles in the range of 1 mm in width of each layer is preferably about 50 or more, more preferably about 70 or more. The number of large particles in the range of 1 mm in width of each layer is preferably about 500 or less, more preferably about 400 or less, still more preferably about 200 or less. The preferred range of the number of large particles in the range of 1 mm in width of each layer is about 30 to 500, about 30 to 400, about 30 to 200, about 50 to 500, about 50 to 400, and about 50 to 200. There are about 70 to 500 pieces, about 70 to 400 pieces, and about 70 to 200 pieces. The number of large particles can be obtained by observing a cross-sectional image (width 1 mm) of each layer in the thickness direction with a scanning electron microscope.

The particle size of the large particles is preferably about 1.0 to 5.0 μm.

When the hardness of the large particles and the resin having a cross section in the thickness direction of the first surface coating layer 7 was measured by the nanoindentation method in an environment of 23 ° C., the hardness of the large particles was the hardness of the resin. It is preferably larger than the hardness. In the present disclosure, the method for measuring hardness by the nanoindentation method is as follows.

<Hardness measured by nanoindentation method in 23 ° C environment>
Hardness is measured using a nanoindenter (for example, "TI950 TriboIndenter" manufactured by HYSITRON) as an apparatus. As the indenter of the nanoindenter, a Berkovich indenter (for example, TI-0039) is used. First, in an environment with a relative humidity of 50% and 23 ° C., the indenter is applied to the surface to be measured (the surface on which the first surface coating layer or the second surface coating layer is exposed, and the thickness direction of each layer). Apply the indenter to the surface parallel to the thickness direction from the direction perpendicular to the thickness direction, push the indenter from the surface to a load of 50 μN over 10 seconds, hold it in that state for 5 seconds, and then unload it over 10 seconds. The average value of N = 5 measured by shifting the measurement points is defined as the hardness. The surface on which the indenter is pushed is exposed in the cross section of the first surface coating layer or the second surface coating layer to be measured, which is obtained by cutting in the thickness direction so as to pass through the central portion of the exterior material for the power storage device. It is a part. Further, in the measurement of the hardness of the resin of the first surface coating layer or the second surface coating layer, the portion where the indenter is pushed is a portion (resin portion) in which particles do not exist on the surface, respectively. In the measurement of the hardness of the particles of the first surface coating layer or the second surface coating layer, it is a portion where the particles are present on the surface. Cutting is performed using a commercially available rotary microtome.

The hardness of the large particles measured by the nanoindentation method is preferably about 400 MPa or more, more preferably about 430 MPa or more. The hardness is preferably about 600 MPa or less. Preferred ranges of the hardness include about 400 to 600 MPa and about 430 to 600 MPa. The large particles having these hardnesses are preferably large organic particles.

In the first surface coating layer 7, the difference between the hardness of the large particles and the hardness of the resin is preferably about 100 MPa or more, more preferably about 130 MPa or more. The hardness is preferably about 300 MPa or less. Further, preferable ranges of the hardness include about 100 to 300 MPa and about 130 to 300 MPa. The large particles having these hardnesses are preferably large organic particles.

The resin contained in the first surface coating layer 7 is preferably a curable resin. That is, the first surface coating layer 7 is preferably composed of a cured product of a resin composition containing a curable resin and silica particles 71.

The curable resin may be either a one-component curable type or a two-component curable type, but is preferably a two-component curable type. Examples of the two-component curable resin include two-component curable polyurethane, two-component curable polyester, and two-component curable epoxy resin. Of these, two-component curable polyurethane is preferable.

Examples of the two-component curable polyurethane include a polyurethane containing a main agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferred are two-component curable polyurethanes containing a polyol such as a polyester polyol, a polyether polyol, and an acrylic polyol as a main component and an aromatic or aliphatic polyisocyanate as a curing agent. Further, as the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group in the side chain in addition to the hydroxyl group at the end of the repeating unit. Examples of the curing agent include aliphatic, alicyclic, aromatic, and aromatic aliphatic isocyanate compounds. Examples of the isocyanate-based compound include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), and diphenylmethane diisocyanate. (MDI), naphthalenediocyanate (NDI) and the like. Moreover, a polyfunctional isocyanate modified product from one kind or two or more kinds of these diisocyanates and the like can be mentioned. Further, a multimer (for example, a trimer) can be used as the polyisocyanate compound. Examples of such a multimer include an adduct body, a biuret body, a nurate body and the like. The aliphatic isocyanate-based compound refers to an isocyanate having an aliphatic group and no aromatic ring, and the alicyclic isocyanate-based compound refers to an isocyanate having an alicyclic hydrocarbon group, which is an aromatic isocyanate-based compound. Refers to an isocyanate having an aromatic ring.

It is preferable that the first surface coating layer 7 and the second surface coating layer 6 contain different resins. More specifically, the resins contained in the first surface coating layer 7 and the second surface coating layer 6 may be different, and the hardness measured by the nanoindentation method may be different for these layers. Preferably, the hardness of the resin of the first surface coating layer 7 is larger than the hardness of the resin of the second surface coating layer 6.

The hardness of the resin of the first surface coating layer 7 as measured by the nanoindentation method is preferably about 150 MPa or more, more preferably about 170 MPa or more. The hardness is preferably about 400 MPa or less, more preferably about 300 MPa or less. Preferred ranges of the hardness include about 150 to 400 MPa, about 150 to 300 MPa, about 170 to 400 MPa, and about 170 to 300 MPa.

The difference between the hardness of the resin of the first surface coating layer 7 and the hardness of the resin of the second surface coating layer 6 is preferably about 100 MPa or more, more preferably about 150 MPa or more. The difference in hardness is preferably about 300 MPa or less, more preferably 250 MPa or less. Preferred ranges of the difference in hardness include about 100 to 300 MPa, about 100 to 250 MPa, about 150 to 300 MPa, and about 150 to 250 MPa. As described above, the hardness of the resin of the scratch resistant layer 7 is preferably larger than the hardness of the resin of the base material protective layer 6.

In the resin composition forming the first surface coating layer 7, when the resin is a polyurethane containing a main agent containing a polyol compound and a curing agent containing an isocyanate compound, for example, the ratio of the main agent and the curing agent is adjusted. By doing so, the hardness of the resin measured by the nanoindentation method can be adjusted.

On at least one of the surface and the inside of the first surface coating layer 7, depending on the functionality to be provided on the first surface coating layer 7 and the surface thereof, if necessary, a lubricant, a colorant, and an antiblocking agent described later will be applied. Additives (additives) such as agents, flame retardants, antioxidants, tackifiers, and antistatic agents may be further contained.

When the first surface coating layer 7 contains a colorant, known colorants such as pigments and dyes can be used as the colorant. Further, only one type of colorant may be used, or two or more types may be mixed and used. Specific examples of the colorant contained in the first surface coating layer 7 include the same colorants as those exemplified in the column of [Adhesive layer 2]. Further, the preferable content of the colorant contained in the first surface coating layer 7 is the same as the content described in the column of [Adhesive layer 2].

The method for forming the first surface coating layer 7 is not particularly limited, and examples thereof include a method of applying a resin composition for forming the first surface coating layer 7. When an additive is blended in the first surface coating layer 7, a resin mixed with the additive may be applied.

In the present disclosure, from the viewpoint of improving the moldability of the exterior material for the power storage device, it is preferable that the lubricant is present on the surface of the first surface coating layer 7. The lubricant is not particularly limited, but an amide-based lubricant is preferable. Specific examples of the amide-based lubricant include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, bechenic acid amide, hydroxystearic acid amide and the like. Specific examples of the unsaturated fatty acid amide include oleic acid amide and erucic acid amide. Specific examples of the substituted amide include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucate amide and the like. Further, specific examples of methylolamide include methylolstearic acid amide. Specific examples of the saturated fatty acid bisamide include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbechenic acid amide, and hexamethylene bisstearic. Examples thereof include acid amides, hexamethylene bisbechenic acid amides, hexamethylene hydroxystearic acid amides, N, N'-distearyl adipate amides, and N, N'-distearyl sebacic acid amides. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N, N'-diorail adipate amide, and N, N'-diorail sebacic acid amide. And so on. Specific examples of the fatty acid ester amide include stearoamide ethyl stearate and the like. Specific examples of the aromatic bisamide include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N, N'-distearyl isophthalic acid amide. One type of lubricant may be used alone, or two or more types may be used in combination.

If a lubricant is present on the surface of the first surface coating layer 7, as its abundance is not particularly limited, preferably about 3 mg / m ² or more, more preferably 4~15mg / m ² approximately, more preferably 5 ~ 14 mg / m ² is mentioned.

The lubricant existing on the surface of the first surface coating layer 7 may be one in which the lubricant contained in the first surface coating layer 7 is exuded, or one in which the lubricant is applied to the surface of the first surface coating layer 7. It may be.

[Second surface coating layer 6]
The exterior material 10 for a power storage device of the present disclosure is the outer material 10 for a power storage device including the first surface coating layer 7 containing silica particles 71, for the purpose of improving the uniformity of the surface state of the surface coating layer. A second surface coating layer 6 is provided between the surface coating layer 7 and the base material layer 1. The second surface coating layer 6 is preferably in contact with the first surface coating layer and the base material layer 1.

Further, as described above, the exterior material 10 for the power storage device of the present disclosure has an average film thickness of 10 μm or less in which the first surface coating layer 7 and the second surface coating layer 6 are combined.

The second surface coating layer 6 contains inorganic particles 61 different from the silica particles 71 and a resin. That is, the second surface coating layer 6 is formed of a resin composition containing inorganic particles 61 different from the silica particles 71 and a resin.

Examples of the inorganic particles 61 different from the silica particles 71 include talc, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, and oxidation. Neodium, 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, gold, aluminum , Copper, nickel and other particles. From the viewpoint of preferably achieving both excellent scratch resistance and excellent uniformity of the surface state of the surface coating layer, the inorganic particles 61 contained in the second surface coating layer 6 are inorganic particles having a larger specific gravity than the silica particles 71. Is preferable, and barium sulfate is particularly preferable. The inorganic particles 61 contained in the second surface coating layer 6 may be of one type or two or more types.

In the second surface coating layer 6, the shape of the inorganic particles 61 is not particularly limited, and examples thereof include a spherical shape, a fibrous shape, a plate shape, an amorphous shape, and a scaly shape, and a spherical shape is preferable.

In the second surface coating layer 6, the average particle size of the inorganic particles 61 is preferably 0.5 nm to 5 μm, for example, from the viewpoint of preferably achieving both excellent scratch resistance and excellent uniformity of the surface state of the surface coating layer. Is about 0.5 to 3 μm.

The average particle size of the inorganic particles 61 is a median size measured by a laser diffraction / scattering type particle size distribution measuring device.

From the viewpoint of preferably achieving both excellent scratch resistance and excellent uniformity of the surface condition of the surface coating layer, the content of the inorganic particles 61 contained in the second surface coating layer 6 is the content of the second surface coating layer 6 With respect to 100 parts by mass of the resin, preferably about 0.1 part by mass or more, more preferably about 0.5 part by mass or more, still more preferably about 1.0 part by mass or more. From the same viewpoint, the content is preferably about 10.0 parts by mass or less, more preferably about 5.0 parts by mass or less, and further preferably about 3.0 parts by mass or less. The preferable range of the content is about 0.1 to 10.0 parts by mass, about 0.1 to 5.0 parts by mass, and 0.1 to 3.0 parts by mass with respect to 100 parts by mass of the resin. About parts, about 0.5 to 10.0 parts by mass, about 0.5 to 5.0 parts by mass, about 0.5 to 3.0 parts by mass, about 1.0 to 10.0 parts by mass, 1.0 About 5.0 parts by mass and about 1.0 to 3.0 parts by mass can be mentioned.

From the viewpoint of preferably achieving both excellent scratch resistance and excellent uniformity of the surface condition of the surface coating layer, the second surface coating layer 6 further contains organic particles 62 in addition to the inorganic particles 61. Is preferable. As the organic particles 62, the same ones as those exemplified in the item of [1st surface coating layer 7] are exemplified. The organic particles 62 contained in the second surface coating layer 6 may be of one type or two or more types.

In the second surface coating layer 6, the particle size of the organic particles 62 is preferably about 5.0 μm or less, from the viewpoint of preferably achieving both excellent scratch resistance and excellent uniformity of the surface state of the surface coating layer. It is preferably about 3.0 μm or less, more preferably about 2.0 μm or less. From the same viewpoint, the particle size of the organic particles 62 is preferably about 0.3 μm or more, more preferably about 0.5 μm or more. The preferred range of the particle size of the organic particles 62 is about 0.3 to 5.0 μm, about 0.3 to 3.0 μm, about 0.3 to 2.0 μm, about 0.5 to 5.0 μm, and the like. Examples thereof include about 0.5 to 3.0 μm and about 0.5 to 2.0 μm. The description of the particle size means that among the organic particles 62 contained in the second surface coating layer 6, organic particles having these particle sizes are predominantly contained. Of the organic particles 62 contained in the second surface coating layer 6, the proportion of the organic particles having these particle sizes is preferably 50% or more, more preferably 80% or more, still more preferably 90% or more, and 100%. It may be.

The particle size of the organic particles 62 is a value measured for a cross-sectional image in the thickness direction of the second surface coating layer 6 observed using a scanning electron microscope. The particle size of the organic particles 62 is the maximum linear distance connecting the leftmost end in the direction perpendicular to the thickness direction of the particles and the rightmost end in the direction perpendicular to the thickness direction with respect to the particle size observed by the scanning electron microscope. Means the diameter that becomes. The particle size of the organic particles 62 is not the average particle size.

The shape of the organic particles 62 is not particularly limited, and examples thereof include a spherical shape, a fibrous shape, a plate shape, an amorphous shape, and a scaly shape, and a spherical shape is preferable.

When the second surface coating layer 6 contains the organic particles 62, the content of the organic particles 62 is 100 mass by mass of the resin, from the viewpoint of preferably achieving both excellent scratch resistance and excellent uniformity of the surface condition of the surface coating layer. With respect to the portion, preferably about 0.01 part by mass or more, more preferably about 0.1 part by mass or more, still more preferably about 0.5 part by mass or more. From the same viewpoint, the content is preferably about 10.0 parts by mass or less, more preferably about 5.0 parts by mass or less, and further preferably about 3.0 parts by mass or less. The preferable range of the content is about 0.01 to 10.0 parts by mass, about 0.01 to 5.0 parts by mass, about 0.01 to 3.0 parts by mass, and 0.1 to 10. About 0 parts by mass, about 0.1 to 5.0 parts by mass, about 0.1 to 3.0 parts by mass, about 0.5 to 10.0 parts by mass, about 0.5 to 5.0 parts by mass, 0 .5 to 3.0 parts by mass.

The average film thickness of the second surface coating layer 6 is not particularly limited as long as the average film thickness of the first surface coating layer 7 and the second surface coating layer 6 is 10 μm or less, but it has excellent scratch resistance and surface coating. From the viewpoint of preferably achieving excellent uniformity of the surface state of the layer, it is preferably about 2.0 μm or less, more preferably about 1.5 μm or less. From the same viewpoint, the average film thickness of the second surface coating layer 6 is preferably about 0.1 μm or more, more preferably about 0.3 μm or more. The preferred range of the average film thickness of the second surface coating layer 6 is about 0.1 to 2.0 μm, about 0.1 to 1.5 μm, about 0.3 to 2.0 μm, and 0.3 to 1.5 μm. The degree can be mentioned. The method for measuring the average film thickness of the second surface coating layer 6 is as described above.

As described above, it is preferable that at least one of the first surface coating layer 7 and the second surface coating layer 6 contains particles having a particle size larger than the average thickness of the layers, and the first surface. It is more preferable that both the coating layer 7 and the second surface coating layer 6 contain the large particles. The large particles are preferably any of the silica particles 71, the inorganic particles 61, and the organic particles 62 and 72, and are preferably the organic particles 62 and 72. That is, when at least one layer of the first surface coating layer 7 and the second surface coating layer 6 contains organic particles 62 and 72, the at least one layer of the first surface coating layer 7 and the second surface coating layer 6 Preferably contains organic particles 62 and 72 having a particle size larger than the average thickness of the layer.

As described above, the particle size of the large particles is preferably about 1.0 to 5.0 μm.

When the hardness of the large particles and the resin having a cross section in the thickness direction of the second surface coating layer 6 was measured by the nanoindentation method in an environment of 23 ° C., the hardness of the large particles was determined by the second surface. It is preferably larger than the hardness of the resin of the coating layer 6. In the present disclosure, the method for measuring hardness by the nanoindentation method is as described above.

The hardness of the large particles of the second surface coating layer 6 measured by the nanoindentation method is preferably about 400 MPa or more, more preferably about 430 MPa or more. The hardness is preferably about 600 MPa or less. Preferred ranges of the hardness include about 400 to 600 MPa and about 430 to 600 MPa. The large particles having these hardnesses are preferably large organic particles.

The resin contained in the second surface coating layer 6 is preferably a curable resin. That is, it is more preferable that the first surface coating layer 7 is composed of a cured product of a resin composition containing a curable resin.

In the second surface coating layer 6, the curable resin may be either a one-component curing type or a two-component curing type, but is preferably a two-component curing type. Examples of the two-component curable resin include two-component curable polyurethane, two-component curable polyester, and two-component curable epoxy resin. Of these, two-component curable polyurethane is preferable.

Examples of the two-component curable polyurethane include the same ones exemplified in the above item [1st surface coating layer 7].

The hardness of the resin of the second surface coating layer 6 measured by the nanoindentation method is preferably about 150 MPa or less, more preferably about 100 MPa or less, still more preferably about 50 MPa or less. The hardness is preferably about 5 MPa or more, more preferably about 10 MPa or more. Preferred ranges of the hardness include about 5 to 150 MPa, about 5 to 100 MPa, about 5 to 50 MPa, about 10 to 150 MPa, about 10 to 100 MPa, and about 10 to 50 MPa.

In the resin composition forming the second surface coating layer 6, when the resin is a polyurethane containing a main agent containing a polyol compound and a curing agent containing an isocyanate compound, for example, the ratio of the main agent and the curing agent is adjusted. By doing so, the hardness of the resin measured by the nanoindentation method can be adjusted.

Inside the second surface coating layer 6, a colorant, an antiblocking agent, a flame retardant, an antioxidant, and an adhesive, which will be described later, are required according to the functionality to be provided in the second surface coating layer 6. Additives such as an imparting agent and an antistatic agent may be further contained.

When the second surface coating layer 6 contains a colorant, known colorants such as pigments and dyes can be used as the colorant. Further, only one type of colorant may be used, or two or more types may be mixed and used. Specific examples of the colorant contained in the second surface coating layer 6 include the same colorants as those exemplified in the column of [Adhesive layer 2]. Further, the preferable content of the colorant contained in the second surface coating layer 6 is also the same as the content described in the column of [Adhesive layer 2].

The method for forming the second surface coating layer 6 is not particularly limited, and examples thereof include a method of applying a resin composition for forming the second surface coating layer 6. When an additive is blended in the second surface coating layer 6, a resin mixed with the additive may be applied.

[Base material layer 1]
In the present disclosure, the base material layer 1 is a layer provided for the purpose of exerting a function as a base material of an exterior material for a power storage device. The base material layer 1 is located between the second surface coating layer 6 and the barrier layer 3 of the exterior material 10 for a power storage device.

The material forming the base material layer 1 is not particularly limited as long as it has a function as a base material, that is, at least an insulating property. The base material layer 1 can be formed by using, for example, a resin, and the resin may contain an additive described later.

When the base material layer 1 is made of a resin, the base material layer 1 may be, for example, a resin film formed of a resin, or may be formed by applying a resin. The resin film may be an unstretched film or a stretched film. Examples of the stretched film include a uniaxially stretched film and a biaxially stretched film, and a biaxially stretched film is preferable. Examples of the stretching method for forming the biaxially stretched film include a sequential biaxial stretching method, an inflation method, and a simultaneous biaxial stretching method. Examples of the method for applying the resin include a roll coating method, a gravure coating method, and an extrusion coating method.

Examples of the resin forming the base material layer 1 include resins such as polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicon resin, and phenol resin, and modified products of these resins. Further, the resin forming the base material layer 1 may be a copolymer of these resins or a modified product of the copolymer. Further, it may be a mixture of these resins.

Among these, preferable examples of the resin forming the base material layer 1 include polyester and polyamide.

Specific examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester. Further, examples of the copolymerized polyester include a copolymerized polyester containing ethylene terephthalate as a repeating unit as a main component. Specifically, copolymer polyester (hereinafter abbreviated after polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / terephthalate /), which polymerizes with ethylene isophthalate using ethylene terephthalate as the main body of the repeating unit. (Sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), polyethylene (terephthalate / decandicarboxylate) and the like. These polyesters may be used alone or in combination of two or more.

Specific examples of the polyamide include an aliphatic polyamide such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and a copolymer of nylon 6 and nylon 66; terephthalic acid and / or isophthalic acid. Hexamethylenediamine-isophthalic acid-terephthalic acid copolymerized polyamide such as nylon 6I, nylon 6T, nylon 6IT, nylon 6I6T (I stands for isophthalic acid, T stands for terephthalic acid), polyamide MXD6 (polymethaki) containing the derived structural units. Polyamide containing aromatics such as silylene adipamide); Alicyclic polyamide such as polyamide PACM6 (polybis (4-aminocyclohexyl) methaneadipamide); Further, lactam component and isocyanate component such as 4,4'-diphenylmethane-diisocyanate Examples thereof include copolymerized polyamides, polyesteramide copolymers and polyether esteramide copolymers which are copolymers of copolymerized polyamides and polyesters and polyalkylene ether glycols; and polyamides such as these copolymers. These polyamides may be used alone or in combination of two or more.

The base material layer 1 preferably contains at least one of a polyester film, a polyamide film, and a polyolefin film, and preferably contains at least one of a stretched polyester film, a stretched polypropylene film, and a stretched polyolefin film. It is more preferable to contain at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, a stretched nylon film, and a stretched polypropylene film, preferably a biaxially stretched polyethylene terephthalate film, a biaxially stretched polybutylene terephthalate film, and a biaxially stretched nylon film. , It is more preferable to contain at least one of the biaxially stretched polypropylene films.

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 laminated body in which a resin film is laminated with an adhesive or the like, or the resin is co-extruded to form two or more layers. It may be a laminated body of the resin film. Further, the laminated body of the resin film obtained by coextruding the resin into two or more layers may be used as the base material layer 1 without being stretched, or may be uniaxially stretched or biaxially stretched as the base material layer 1.

Specific examples of the laminate of two or more layers of resin film in the base material layer 1 include a laminate of a polyester film and a nylon film, a laminate of two or more layers of nylon film, and a laminate of two or more layers of polyester film. And the like, preferably, a laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more layers of stretched nylon film, and a laminate of two or more layers of stretched polyester film are preferable. For example, when the base material layer 1 is a laminate of two layers of resin film, a laminate of polyester resin film and polyester resin film, a laminate of polyamide resin film and polyamide resin film, or a laminate of polyester resin film and polyamide resin film. A laminate is preferable, and a laminate of a polyethylene terephthalate film and a polyethylene terephthalate film, a laminate of a nylon film and a nylon film, or a laminate of a polyethylene terephthalate film and a nylon film is more preferable. Further, since the polyester resin is difficult to discolor when the electrolytic solution adheres to the surface, for example, when the base material layer 1 is a laminate of two or more resin films, the polyester resin film is the base material layer 1. It is preferably located in the outermost layer.

When the base material layer 1 is a laminate of two or more layers of resin films, the two or more layers of resin films may be laminated via an adhesive. Preferred adhesives include those similar to the adhesives exemplified in the adhesive layer 2 described later. The method of laminating two or more layers of resin films is not particularly limited, and known methods can be adopted. Examples thereof include a dry laminating method, a sandwich laminating method, an extrusion laminating method, and a thermal laminating method, and a dry laminating method is preferable. The laminating method can be mentioned. When laminating by the dry laminating method, it is preferable to use a polyurethane adhesive as the adhesive. At this time, the thickness of the adhesive is, for example, about 2 to 5 μm. Further, an anchor coat layer may be formed on the resin film and laminated. Examples of the anchor coat layer include the same adhesives as those exemplified in the adhesive layer 2 described later. At this time, the thickness of the anchor coat layer is, for example, about 0.01 to 1.0 μm.

Further, additives such as a flame retardant, an antiblocking agent, an antioxidant, a light stabilizer, a tackifier, and an antistatic agent may be present on at least one of the surface and the inside of the base material layer 1. Only one type of additive may be used, or two or more types may be mixed and used.

The thickness of the base material layer 1 is not particularly limited as long as it functions as a base material, and examples thereof include about 3 to 50 μm, preferably about 10 to 35 μm. When the base material layer 1 is a laminate of two or more resin films, the thickness of the resin films constituting each layer is preferably about 2 to 25 μm, respectively.

[Adhesive layer 2]
In the exterior material for a power storage device of the present disclosure, the adhesive layer 2 is a layer provided between the base material layer 1 and the barrier layer 3 as necessary for the purpose of enhancing the adhesiveness between the base material layer 1 and the barrier layer 3.

The adhesive layer 2 is formed by an adhesive capable of adhering the base material layer 1 and the barrier layer 3. The adhesive used for forming the adhesive layer 2 is not limited, but may be any of a chemical reaction type, a solvent volatile type, a heat melting type, a hot pressure type and the like. Further, it may be a two-component curable adhesive (two-component adhesive), a one-component curable adhesive (one-component adhesive), or a resin that does not involve a curing reaction. Further, the adhesive layer 2 may be a single layer or a multilayer.

Specific examples of the adhesive component contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester; polyether; polyurethane; epoxy resin; Phenolic resin; Polyethylene such as nylon 6, nylon 66, nylon 12, copolymerized polyamide; Polyethylene resin such as polyolefin, cyclic polyolefin, acid-modified polyolefin, acid-modified cyclic polyolefin; Polyvinyl acetate; Cellulose; (Meta) acrylic resin; Polyethylene; polycarbonate; amino resin such as urea resin and melamine resin; rubber such as chloroprene rubber, nitrile rubber and styrene-butadiene rubber; silicone resin and the like. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, a polyurethane adhesive is preferable. In addition, the resins used as these adhesive components can be used in combination with an appropriate curing agent to increase the adhesive strength. An appropriate curing agent is selected from polyisocyanate, polyfunctional epoxy resin, oxazoline group-containing polymer, polyamine resin, acid anhydride and the like, depending on the functional group of the adhesive component.

Examples of the polyurethane adhesive include a polyurethane adhesive containing a main agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferred are two-component curable polyurethane adhesives containing a polyol such as a polyester polyol, a polyether polyol, and an acrylic polyol as a main component and an aromatic or aliphatic polyisocyanate as a curing agent. Further, as the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group in the side chain in addition to the hydroxyl group at the end of the repeating unit. Since the adhesive layer 2 is formed of a polyurethane adhesive, excellent electrolytic solution resistance is imparted to the exterior material for the power storage device, and even if the electrolytic solution adheres to the side surface, the base material layer 1 is suppressed from peeling off. ..

Further, the adhesive layer 2 may contain a colorant, a thermoplastic elastomer, a tackifier, a filler and the like, as long as the adhesiveness is not impaired, the addition of other components is permitted. Since the adhesive layer 2 contains a colorant, the exterior material for the power storage device can be colored. As the colorant, known ones such as pigments and dyes can be used. Further, only one type of colorant may be used, or two or more types may be mixed and used.

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, anthracinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindrenine-based, and benzimidazolone-based pigments, which are inorganic. Examples of the pigment include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments, and other examples include fine powder of mica (mica) and fish scale foil.

Among the colorants, carbon black is preferable in order to make the appearance of the exterior material for a power storage device black, for example.

The average particle size of the pigment is not particularly limited, and examples thereof include about 0.05 to 5 μm, preferably about 0.08 to 2 μm. The average particle size of the pigment is the median diameter measured by a laser diffraction / scattering type particle size distribution measuring device.

The content of the pigment in the adhesive layer 2 is not particularly limited as long as the exterior material for the power storage device is colored, and examples thereof include about 5 to 60% by mass, preferably 10 to 40% by mass.

The thickness of the adhesive layer 2 is not particularly limited as long as the base material layer 1 and the barrier layer 3 can be adhered to each other, but is, for example, about 1 μm or more and about 2 μm or more. The thickness of the adhesive layer 2 is, for example, about 10 μm or less and about 5 μm or less. The preferable range of the thickness of the adhesive layer 2 is about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

[Colored layer]
The colored layer is a layer provided between the base material layer 1 and the barrier layer 3 as needed (not shown). When the adhesive layer 2 is provided, a colored layer may be provided between the base material layer 1 and the adhesive layer 2 and between the adhesive layer 2 and the barrier layer 3. Further, a colored layer may be provided on the outside of the base material layer 1. By providing the coloring layer, the exterior material for the power storage device can be colored.

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

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

[Barrier layer 3]
In the exterior material for a power storage device, the barrier layer 3 is at least a layer that suppresses the infiltration of water.

Examples of the barrier layer 3 include a metal foil having a barrier property, a thin-film deposition film, a resin layer, and the like. Examples of the vapor deposition film include a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, and the like, and examples of the resin layer include polymers and tetras mainly composed of polyvinylidene chloride and chlorotrifluoroethylene (CTFE). Examples thereof include polymers containing fluoroethylene (TFE) as a main component, polymers having a fluoroalkyl group, fluorine-containing resins such as polymers containing fluoroalkyl units as a main component, and ethylene vinyl alcohol copolymers. Further, examples of the barrier layer 3 include a resin film provided with at least one of these vapor-deposited films and a resin layer. A plurality of barrier layers 3 may be provided. The barrier layer 3 preferably includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 3 include an aluminum alloy, stainless steel, titanium steel, and a steel plate. When used as a metal foil, the metal material includes at least one of an aluminum alloy foil and a stainless steel foil. Is preferable.

From the viewpoint of improving the moldability of the exterior material for the power storage device, the aluminum alloy foil is more preferably a soft aluminum alloy foil composed of, for example, an annealed aluminum alloy, and from the viewpoint of further improving the moldability. Therefore, it is preferable that the aluminum alloy foil contains iron. 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. When the iron content is 0.1% by mass or more, an exterior material for a power storage device having more excellent moldability can be obtained. When the iron content is 9.0% by mass or less, a more flexible exterior material for a power storage device can be obtained. Examples of the soft aluminum alloy foil include an aluminum alloy having a composition defined by JIS H4160: 1994 A8021H-O, JIS H4160: 1994 A8079H-O, JIS H4000: 2014 A8021P-O, or JIS H4000: 2014 A8079P-O. Foil is mentioned. Further, if necessary, silicon, magnesium, copper, manganese and the like may be added. Further, softening can be performed by annealing or the like.

Examples of the stainless steel foil include austenite-based, ferrite-based, austenite-ferritic-based, martensitic-based, and precipitation-hardened stainless steel foils. Further, from the viewpoint of providing an exterior material for a power storage device having excellent moldability, the stainless steel foil is preferably made of austenitic stainless steel.

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

In the case of a metal foil, the thickness of the barrier layer 3 may be at least a function as a barrier layer for suppressing the infiltration of water, and is, for example, about 9 to 200 μm. The thickness of the barrier layer 3 is preferably about 85 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, and particularly preferably about 35 μm or less. The thickness of the barrier layer 3 is preferably about 10 μm or more, more preferably about 20 μm or more, and more preferably about 25 μm or more. The preferable range of the thickness is about 10 to 85 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, and about 25 to 25. Examples thereof include about 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 3 is made of an aluminum alloy foil, the above range is particularly preferable. Further, in particular, when the barrier layer 3 is made of stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, still more preferably about. 30 μm or less, 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. The preferred thickness range of the stainless steel foil is 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, and about 15 to 50 μm. Examples thereof include about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

When the barrier layer 3 is a metal foil, it is preferable that a corrosion-resistant film is provided on at least the surface opposite to the base material layer in order to prevent dissolution and corrosion. The barrier layer 3 may be provided with a corrosion-resistant film on both sides. Here, the corrosion-resistant film is, for example, a hot water transformation treatment such as boehmite treatment, a chemical conversion treatment, an anodization treatment, a plating treatment such as nickel or chromium, and a corrosion prevention treatment for applying a coating agent on the surface of the barrier layer. A thin film that makes the barrier layer corrosion resistant. As the treatment for forming the corrosion-resistant film, one type may be performed, or two or more types may be combined. Moreover, not only one layer but also multiple layers can be used. Further, among these treatments, the hydrothermal modification treatment and the anodizing treatment are treatments in which the surface of the metal foil is dissolved by a treatment agent to form a metal compound having excellent corrosion resistance. In addition, these processes may be included in the definition of chemical conversion process. When the barrier layer 3 has a corrosion-resistant film, the barrier layer 3 includes the corrosion-resistant film.

The corrosion-resistant film is formed by preventing delamination between the barrier layer (for example, aluminum alloy foil) and the base material layer during molding of the exterior material for a power storage device, and by hydrogen fluoride generated by the reaction between the electrolyte and water. , Melting and corrosion of the surface of the barrier layer, especially when the barrier layer is an aluminum alloy foil, it prevents the aluminum oxide existing on the surface of the barrier layer from melting and corroding, and the adhesiveness (wetness) of the surface of the barrier layer. The effect of preventing the corrosion between the base material layer and the barrier layer at the time of heat sealing and the prevention of the corrosion between the base material layer and the barrier layer at the time of molding is shown.

Various corrosion-resistant films formed by chemical conversion treatment are known, and mainly, at least one of phosphate, chromate, fluoride, triazinethiol compound, and rare earth oxide. Examples include a corrosion-resistant film containing. Examples of the chemical conversion treatment using a phosphate or a chromate include a chromic acid chromate treatment, a phosphoric acid chromate treatment, a phosphoric acid-chromate treatment, a chromate treatment, and the like, and chromium used in these treatments. Examples of the compound include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium dichromate, acetylacetate chromate, chromium chloride, and chromium potassium sulfate. In addition, examples of the phosphorus compound used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid and the like. Further, examples of the chromate treatment include etching chromate treatment, electrolytic chromate treatment, and coating type chromate treatment, and coating type chromate treatment is preferable. In this coating type chromate treatment, at least the inner layer side surface of the barrier layer (for example, aluminum alloy foil) is first known as an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid activation method and the like. After degreasing by the treatment method, metal phosphates such as Cr phosphate (chromium) salt, Ti (titanium) phosphate, Zr (zyroxide) salt, Zn (zinc) phosphate, etc. A treatment liquid containing a salt and a mixture of these non-metal salts as a main component, or a treatment liquid containing a mixture of a phosphate non-metal salt and these non-metal salts as a main component, or a synthetic resin and the like. This is a treatment in which a treatment liquid composed of a mixture is coated by a well-known coating method such as a roll coating method, a gravure printing method, or a dipping method, and dried. As the treatment liquid, for example, various solvents such as water, alcohol-based solvent, hydrocarbon-based solvent, ketone-based solvent, ester-based solvent, and ether-based solvent can be used, and water is preferable. Examples of the resin component used at this time include polymers such as phenolic resin and acrylic resin, and aminoated phenol polymers having repeating units represented by the following general formulas (1) to (4). Examples thereof include the chromate treatment used. In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more. May be good. The acrylic resin shall be a polyacrylic acid, an acrylic acid methacrylate copolymer, an acrylic acid maleic acid copolymer, an acrylic acid styrene copolymer, or a derivative of these sodium salts, ammonium salts, amine salts, etc. Is preferable. In particular, derivatives of polyacrylic acid such as ammonium salt, sodium salt, and amine salt of polyacrylic acid are preferable. In the present disclosure, polyacrylic acid means a polymer of acrylic acid. Further, the acrylic resin is preferably a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride, and an ammonium salt, a sodium salt, or a copolymer of an acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride. Alternatively, it is preferably an amine salt. Only one type of acrylic resin may be used, or two or more types may be mixed and used.

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. Further, R ¹ and R ² represent a hydroxy group, an alkyl group, or a hydroxyalkyl group, respectively, which are the same or different. In the general formulas (1) to (4) ^{, examples of the alkyl group represented by X, R 1} and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group and an isobutyl group. Examples thereof include a linear or branched alkyl group having 1 to 4 carbon atoms such as a tert-butyl group. Examples of the hydroxyalkyl groups represented by X, R ¹ and R ² include a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group and 3-. A linear or branched chain having 1 to 4 carbon atoms in which one hydroxy group such as a hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, or a 4-hydroxybutyl group is substituted. Alkyl groups can be mentioned. In the general formulas (1) to (4), the ^{alkyl group and the hydroxyalkyl group represented by X, R 1} and R ² may be the same or different, respectively. In the general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxy group or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having the repeating unit represented by the general formulas (1) to (4) is, for example, preferably about 5 to 1,000,000, and preferably about 1,000 to 20,000. More preferred. The amination phenol polymer, for example, polycondenses a phenol compound or a naphthol compound with formaldehyde to produce a polymer composed of repeating units represented by the above general formula (1) or general formula (3), and then formsaldehyde. It is produced by introducing a functional group (-CH ₂ NR ¹ R ² ) into the polymer obtained above using amine (R ¹ R ^{2 NH).} The aminated phenol polymer is used alone or in admixture of two or more.

As another example of the corrosion resistant film, it is 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 thin film to be corroded is mentioned. The coating agent may further contain phosphoric acid or phosphate, a cross-linking agent for cross-linking the polymer. In the rare earth element oxide sol, fine particles of the rare earth element oxide (for example, particles having an average particle size of 100 nm or less) are dispersed in a liquid dispersion medium. Examples of the rare earth element oxide include cerium oxide, yttrium oxide, neodymium oxide, lanthanum oxide and the like, and cerium oxide is preferable from the viewpoint of further improving adhesion. The rare earth element oxide contained in the corrosion-resistant film may be used alone or in combination of two or more. As the liquid dispersion medium of the rare earth element oxide sol, for example, various solvents such as water, alcohol-based solvent, hydrocarbon-based solvent, ketone-based solvent, ester-based solvent, and ether-based solvent can be used, and water is preferable. Examples of the cationic polymer include polyethyleneimine, an ionic polymer complex composed of polyethyleneimine and a polymer having a carboxylic acid, a primary amine graft acrylic resin obtained by graft-polymerizing a primary amine on an acrylic main skeleton, polyallylamine or a derivative thereof. , Amination phenol and the like are preferable. The anionic polymer is preferably a poly (meth) acrylic acid or a salt thereof, or a copolymer containing (meth) acrylic acid or a salt thereof as a main component. Further, it is preferable that the cross-linking agent is at least one selected from the group consisting of a compound having a functional group of any of an isocyanate group, a glycidyl group, a carboxyl group and an oxazoline group and a silane coupling agent. Further, it is preferable that the phosphoric acid or phosphate is condensed phosphoric acid or condensed phosphate.

As an example of the corrosion-resistant film, a film in which fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide and barium sulfate are dispersed in phosphoric acid is applied to the surface of the barrier layer, and 150 Examples thereof include those formed by performing a baking treatment at a temperature of ° C. or higher.

The corrosion-resistant film may have a laminated structure in which at least one of a cationic polymer and an anionic polymer is further laminated, if necessary. Examples of the cationic polymer and the anionic polymer include those described above.

The composition of the corrosion-resistant film can be analyzed by using, for example, a time-of-flight secondary ion mass spectrometry method.

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, but for example, in the case of performing a coating type chromate treatment, a chromic acid compound per ^{1 m 2 of the surface of the barrier layer 3} Is, for example, about 0.5 to 50 mg, preferably about 1.0 to 40 mg in terms of chromium, and the phosphorus compound is, for example, about 0.5 to 50 mg, preferably about 1.0 to 40 mg in terms of phosphorus, and an amination phenol polymer. Is preferably contained in a proportion of, for example, about 1.0 to 200 mg, preferably about 5.0 to 150 mg.

The thickness of the corrosion-resistant film is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably 1 nm to 100 nm, from the viewpoint of the cohesive force of the film and the adhesion to the barrier layer and the thermosetting resin layer. The degree, more preferably about 1 nm to 50 nm. The thickness of the corrosion-resistant film can be measured by observation with a transmission electron microscope or a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron beam energy loss spectroscopy. The time-of-flight secondary ion mass spectrometry analysis of the composition of the corrosion resistant coating using, for example, secondary ion consisting Ce and P and O ^{_{(e.g., Ce 2 PO 4 +, CePO}} 4 - at least 1, such as species) or, for example, secondary ion of Cr and P and O (e.g., CrPO ₂ ^+, CrPO ₄ ^- peak derived from at least one), such as is detected.

In the chemical conversion treatment, a solution containing a compound used for forming a corrosion-resistant film is applied to the surface of the barrier layer by a bar coating method, a roll coating method, a gravure coating method, a dipping method, or the like, and then the temperature of the barrier layer is applied. It is carried out by heating so that the temperature is about 70 to 200 ° C. Further, before the chemical conversion treatment is applied to the barrier layer, the barrier layer may be subjected to a degreasing treatment by an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method or the like in advance. By performing the degreasing treatment in this way, it becomes possible to more efficiently perform the chemical conversion treatment on the surface of the barrier layer. Further, by using an acid degreasing agent in which a fluorine-containing compound is dissolved in an inorganic acid for the degreasing treatment, it is possible to form not only the degreasing effect of the metal foil but also the immobile metal fluoride. In such cases, only degreasing treatment may be performed.

[Thermosetting resin layer 4]
In the exterior material for a power storage device of the present disclosure, the thermosetting resin layer 4 corresponds to the innermost layer, and has a function of heat-sealing the heat-sealing resin layers with each other when assembling the power storage device to seal the power storage device element. It is a layer (sealant layer) that exerts.

The resin constituting the heat-fusing resin layer 4 is not particularly limited as long as it can be heat-fused, but a resin containing a polyolefin skeleton such as polyolefin or acid-modified polyolefin is preferable. The fact that the resin constituting the heat-sealing resin layer 4 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like. Further, when the resin constituting the thermosetting resin layer 4 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride is detected. For example, when measuring the infrared spectroscopy at a maleic anhydride-modified polyolefin, a peak derived from maleic acid is detected in the vicinity of the wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1. When the thermosetting resin layer 4 is a layer composed of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected when measured by infrared spectroscopy. However, if the degree of acid denaturation is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Specific examples of the polyolefin include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; homopolypropylene and block copolymers of polypropylene (for example, with propylene). Polypropylene such as (block copolymer of ethylene), random copolymer of polypropylene (eg, random copolymer of propylene and ethylene); propylene-α-olefin copolymer; terpolymer of ethylene-butene-propylene and the like. Among these, polypropylene is preferable. When it is a copolymer, the polyolefin resin may be a block copolymer or a random copolymer. One type of these polyolefin resins may be used alone, or two or more types may be used in combination.

Further, the polyolefin may be a cyclic polyolefin. The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin which is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Be done. Examples of the cyclic monomer which is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; cyclic diene such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these, cyclic alkene is preferable, and norbornene is more preferable.

The acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of polyolefin with an acid component. As the acid-modified polyolefin, the above-mentioned polyolefin, a copolymer obtained by copolymerizing the above-mentioned polyolefin with a polar molecule such as acrylic acid or methacrylic acid, or a polymer such as a crosslinked polyolefin can also be used. Examples of the acid component used for acid modification include carboxylic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride, or anhydrides thereof.

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 instead of the acid component, or by block-polymerizing or graft-polymerizing the acid component with the cyclic polyolefin. is there. The same applies to the cyclic polyolefin that is acid-modified. The acid component used for acid denaturation is the same as the acid component used for denaturation of the polyolefin.

Preferred acid-modified polyolefins include polyolefins modified with carboxylic acid or its anhydride, polypropylene modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefin, and maleic anhydride-modified polypropylene.

The thermosetting resin layer 4 may be formed of one type of resin alone, or may be formed of a blended polymer in which two or more types of resins are combined. Further, the thermosetting resin layer 4 may be formed of only one layer, but may be formed of two or more layers with the same or different resins.

Further, the thermosetting resin layer 4 may contain a lubricant or the like, if necessary. When the heat-sealing resin layer 4 contains a lubricant, the moldability of the exterior material for a power storage device can be improved. The lubricant is not particularly limited, and a known lubricant can be used. The lubricant may be used alone or in combination of two or more.

The lubricant is not particularly limited, but an amide-based lubricant is preferable. Specific examples of the lubricant include those exemplified in the first surface coating layer 7. One type of lubricant may be used alone, or two or more types may be used in combination.

When the lubricant is present on the surface of the thermosetting resin layer 4, the amount of the lubricant is not particularly limited, but from the viewpoint of improving the moldability of the exterior material for the power storage device, it is preferably about ^{10 to 50 mg / m 2.} , More preferably about 15 to 40 mg / m ^2.

The lubricant existing on the surface of the thermosetting resin layer 4 may be one in which the lubricant contained in the resin constituting the thermosetting resin layer 4 is exuded, or the lubricant of the thermosetting resin layer 4 may be exuded. The surface may be coated with a lubricant.

The thickness of the thermosetting resin layer 4 is not particularly limited as long as the thermosetting resin layers have a function of heat-sealing to seal the power storage device element, but is preferably about 100 μm or less, preferably about 100 μm or less. It is about 85 μm or less, more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 5 described later is 10 μm or more, the thickness of the thermosetting 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 later is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the thermosetting resin layer 4 is preferably about 20 μm or more, more preferably 35 to 85 μm. The degree can be mentioned.

[Adhesive layer 5]
In the exterior material for a power storage device of the present disclosure, the adhesive layer 5 is provided between the barrier layer 3 (or the acid-resistant film) and the thermosetting resin layer 4 as necessary in order to firmly bond them. It is a layer.

The adhesive layer 5 is formed of a resin capable of adhering the barrier layer 3 and the thermosetting resin layer 4 to each other. As the resin used for forming the adhesive layer 5, for example, the same resin as the adhesive exemplified in the adhesive layer 2 can be used. Further, from the viewpoint of firmly adhering the adhesive layer 5 and the heat-sealing resin layer 4, it is preferable that the resin used for forming the adhesive layer 5 contains a polyolefin skeleton, and the above-mentioned heat-sealing property Examples thereof include the polyolefin exemplified in the resin layer 4 and the acid-modified polyolefin. On the other hand, from the viewpoint of firmly adhering the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 preferably contains an acid-modified polyolefin. Examples of the acid-modifying component include dicarboxylic acids such as maleic acid, itaconic acid, succinic acid, and adipic acid, and anhydrides thereof, acrylic acid, and methacrylic acid. Maleic acid is most preferred. From the viewpoint of heat resistance of the exterior material for the power storage device, the olefin component is preferably polypropylene-based resin, and the adhesive layer 5 most preferably contains maleic anhydride-modified polypropylene.

The fact that the resin constituting the adhesive layer 5 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like, and the analysis method is not particularly limited. Further, the resin constituting the adhesive layer 5 comprises an acid-modified polyolefin, for example, when measuring the infrared spectroscopy at maleic anhydride-modified polyolefin, anhydride in the vicinity of a wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1 A peak derived from maleic anhydride is detected. However, if the degree of acid denaturation is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Further, from the viewpoint of ensuring durability such as heat resistance and content resistance of the exterior material for a power storage device and ensuring moldability while reducing the thickness, the adhesive layer 5 is a resin composition containing an acid-modified polyolefin and a curing agent. It is more preferably a cured product. As the acid-modified polyolefin, the above-mentioned ones are preferably exemplified.

The adhesive layer 5 is 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. It is particularly preferable that the resin composition is a cured product 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. Further, 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. As the polyester, for example, an ester resin produced by the reaction of an epoxy group and a maleic anhydride group, and an amide ester resin produced by a reaction of an oxazoline group and a maleic anhydride group are preferable. When an unreacted substance of a curing agent such as a compound having an isocyanate group, a compound having an oxazoline group, or an epoxy resin remains in the adhesive layer 5, the presence of the unreacted substance is determined by, for example, infrared spectroscopy. It can be confirmed by a method selected from Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and the like.

Further, from the viewpoint of further enhancing the adhesion between the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 is selected from at least a group consisting of an oxygen atom, a heterocycle, a C = N bond, and a C—O—C bond. It is preferably a cured product of a resin composition containing a curing agent having one type. Examples of the curing agent having a heterocycle include a curing agent having an oxazoline group and a curing agent having an epoxy group. Examples of the curing agent having a C = N bond include a curing agent having an oxazoline group and a curing agent having an isocyanate group. Examples of the curing agent having a C—O—C bond include a curing agent having an oxazoline group and a curing agent having an epoxy group. The fact that the adhesive layer 5 is a cured product of a resin composition containing these curing agents is, for example, gas chromatograph mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF). -SIMS), X-ray photoelectron spectroscopy (XPS) and other methods can be used for confirmation.

The compound having an isocyanate group is not particularly limited, but a polyfunctional isocyanate compound is preferable from the viewpoint of effectively enhancing the adhesion between the barrier layer 3 and the adhesive layer 5. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of the polyfunctional isocyanate-based curing agent include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and a large amount of these. Can be mentioned. Examples of the multimer include a dimer uretdione, a trimer nurate, a biuret, and an adduct added to a polyhydric alcohol (for example, trimethylolpropane). In addition, MDI also includes a multimer (polymeric MDI) produced as an oligomer.

The content of the compound having an isocyanate group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. More preferably in the range. As a result, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

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.

The proportion of the compound having an oxazoline group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. It is more preferable to be in. As a result, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

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

Specific examples of the epoxy resin include glycidyl ether derivative of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, bisphenol F type glycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether and the like. Can be mentioned. One type of epoxy resin may be used alone, or two or more types may be used in combination.

The proportion of the epoxy resin in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Is more preferable. As a result, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

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

The proportion of polyurethane in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. More preferred. As a result, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced in an atmosphere in which a component that induces corrosion of the barrier layer such as an electrolytic solution is present.

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

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

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

3. 3. Method for Manufacturing Exterior Material for Power Storage Device The method for manufacturing the exterior material for power storage device is not particularly limited as long as a laminated body in which each layer of the exterior material for power storage device of the present disclosure is laminated can be obtained, and the method is not particularly limited. At least, a method comprising a step of obtaining a laminate in which the first surface coating layer 7, the second surface coating layer 6, the base material layer 1, the barrier layer 3, and the heat-sealing resin layer 4 are laminated. Can be mentioned. Specifically, in the method for producing an exterior material for a power storage device of the present disclosure, at least in order from the outside, a surface coating layer, a base material layer, a barrier layer, and a heat-sealing resin layer are laminated. The surface coating layer includes a first surface coating layer and a second surface coating layer from the outside, and the first surface coating layer includes silica particles and a resin. The second surface coating layer contains inorganic particles different from the silica particles and a resin, and the average thickness of the surface coating layer is 10 μm or less.

An example of the method for manufacturing the exterior material for the power storage device of the present disclosure is as follows. First, a laminate in which the base material layer 1, the adhesive layer 2, and the barrier layer 3 are laminated in this order (hereinafter, may be referred to as “laminate A”) is formed. Specifically, the laminated body A is formed by applying an adhesive used for forming the adhesive layer 2 on the base material layer 1 or, if necessary, on the barrier layer 3 whose surface has been chemically converted, by a gravure coating method. It can be carried out by a dry laminating method in which the barrier layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured after being applied and dried by a coating method such as a roll coating method.

Next, the thermosetting resin layer 4 is laminated on the barrier layer 3 of the laminated body A. When the thermosetting resin layer 4 is directly laminated on the barrier layer 3, the thermosetting resin layer 4 is laminated on the barrier layer 3 of the laminated body A by a method such as a thermal laminating method or an extrusion laminating method. do it. When the adhesive layer 5 is provided between the barrier layer 3 and the heat-sealing resin layer 4, for example, (1) the adhesive layer 5 and the heat-sealing resin layer are placed on the barrier layer 3 of the laminated body A. A method of laminating 4 by extruding (co-extrusion laminating method, tandem laminating method), (2) Separately, a laminated body in which the adhesive layer 5 and the heat-sealing resin layer 4 are laminated is formed, and the laminated body A is formed. A laminated body in which the adhesive layer 5 is laminated on the barrier layer 3 of the laminated body A is formed by a method of laminating on the barrier layer 3 of the above, and this is formed by a heat-sealing resin layer 4 and a thermal laminating method. Method of Laminating, (3) While pouring the melted adhesive layer 5 between the barrier layer 3 of the laminated body A and the heat-sealing resin layer 4 formed into a sheet in advance, the adhesive layer 5 is passed through. A method of laminating the laminate A and the heat-sealing resin layer 4 (sandwich lamination method), (4) a solution coating of an adhesive for forming the adhesive layer 5 on the barrier layer 3 of the laminate A is performed. Examples thereof include a method of laminating by a method of drying, a method of baking, and the like, and a method of laminating a heat-sealing resin layer 4 having a sheet-like film formed in advance on the adhesive layer 5.

Next, the second surface coating layer 6 and the first surface coating layer 7 are sequentially laminated on the surface of the base material layer 1 opposite to the barrier layer 3. For the second surface coating layer 6 and the first surface coating layer 7, for example, the above resin composition forming the second surface coating layer 6 and the first surface coating layer 7 is applied to the surface of the base material layer 1, respectively. It can be formed by curing. The order of the step of laminating the barrier layer 3 on the surface of the base material layer 1 and the step of laminating the second surface coating layer 6 and the first surface coating layer 7 on the surface of the base material layer 1 is not particularly limited. .. For example, after forming the second surface coating layer 6 and the first surface coating layer 7 on the surface of the base material layer 1, the barrier layer 3 is formed on the surface of the base material layer 1 opposite to the second surface coating layer 6 side. It may be formed.

As described above, in order from the outside, the first surface coating layer 7 / the second surface coating layer 6 / the base material layer 1 / the adhesive layer 2 provided as needed / the barrier layer 3 / provided as needed. A laminated body including the adhesive layer 5 / thermosetting resin layer 4 is formed, but in order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 provided as needed, further heat treatment is performed. May be served. Further, as described above, a colored layer may be provided between the base material layer 1 and the barrier layer 3.

4. Applications of exterior materials for power storage devices The exterior materials for power storage devices of the present disclosure are used for packaging for sealing and accommodating power storage device elements such as positive electrodes, negative electrodes, and electrolytes. That is, a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte can be housed in a package formed of the exterior material for a power storage device of the present disclosure to form a power storage device.

Specifically, a power storage device element having at least a positive electrode, a negative electrode, and an electrolyte is provided in a state in which metal terminals connected to each of the positive electrode and the negative electrode are projected outward in the exterior material for the power storage device of the present disclosure. , The peripheral edge of the power storage device element is covered so that a flange portion (a region where the heat-sealing resin layers come into contact with each other) can be formed, and the heat-sealing resin layers of the flange portion are heat-sealed and sealed. Provides a power storage device using an exterior material for the power storage device. When the power storage device element is housed in the package formed of the exterior material for the power storage device of the present disclosure, the thermosetting resin portion of the exterior material for the power storage device of the present disclosure is inside (the surface in contact with the power storage device element). ) To form a package.

The exterior material for a power storage device of the present disclosure can be suitably used for a power storage device such as a battery (including a capacitor, a capacitor, etc.). Further, the exterior material for the power storage device of the present disclosure may be used for either a primary battery or a secondary battery, but is preferably a secondary battery. The type of the secondary battery to which the exterior material for the power storage device of the present disclosure is applied is not particularly limited, and for example, a lithium ion battery, a lithium ion polymer battery, an all-solid-state battery, a lead storage battery, a nickel / hydrogen storage battery, and a nickel / hydrogen storage battery. Examples thereof include cadmium storage batteries, nickel / iron storage batteries, nickel / zinc storage batteries, silver oxide / zinc storage batteries, metal air batteries, polyvalent cation batteries, capacitors, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries can be mentioned as suitable application targets of the exterior materials for power storage devices of the present disclosure.

The present disclosure will be described in detail below with reference to Examples and Comparative Examples. However, the present disclosure is not limited to the examples.

<Manufacturing of exterior materials for power storage devices>
Example 1
A stretched nylon (ONy) film (thickness 15 μm) was prepared as a base material layer. Further, as a barrier layer, an aluminum foil (JIS H4160: 1994 A8021HO (thickness 35 μm)) was prepared. Next, the barrier layer and the base material layer are laminated by a dry laminating method using a two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound), and then an aging treatment is performed to carry out a base material. A layer / adhesive layer / barrier layer laminate was prepared. Both sides of the aluminum foil are subjected to chemical conversion treatment. The chemical conversion treatment of the aluminum foil is performed by applying a treatment liquid consisting of a phenol resin, a chromium fluoride compound, and phosphoric acid to both sides of the aluminum foil by a roll coating method so that the ^{amount of chromium applied is 10 mg / m 2 (dry mass).} This was done by coating and baking.

Next, on the barrier layer of each of the above-mentioned laminates, maleic anhydride-modified polypropylene as an adhesive layer (thickness 20 μm) and random polypropylene as a thermosetting resin layer (thickness 20 μm) Was co-extruded to laminate an adhesive layer / thermosetting resin layer on the barrier layer.

Next, on the surface of the base material layer of the obtained laminate, barium sulfate (average particle size of about 1 μm), resin (polyurethane formed from a mixture of one type of polyol compound and an aliphatic isocyanate compound), and polystyrene A second surface coating layer (average thickness 0.77 μm) was formed by applying a resin composition containing organic particles (particle size of about 2 μm) by a gravure printing method. Further, on the surface of the second surface coating layer, silica (average particle size of about 1.5 μm), resin (polyurethane formed from a mixture of two kinds of polyol compounds and an aliphatic isocyanate compound), and polystyrene organic particles (polyurethane formed from a mixture of two kinds of polyol compounds and an aliphatic isocyanate compound) and polystyrene organic particles ( A first surface coating layer (average thickness 0.77 μm) is formed by applying a resin composition containing (with a particle size of about 2 μm) by a gravure printing method, and the first surface coating layer is formed in order from the outside. (Average thickness 0.99 μm) / Second surface coating layer (Average thickness 0.77 μm) / Base material layer (15 μm) / Adhesive layer (3 μm) / Barrier layer (35 μm) / Adhesive layer (20 μm) / Heat A laminated body in which a fusing resin layer (20 μm) was laminated was obtained.

Example 2
The first surface coating layer is in order from the outside in the same manner as in Example 1 except that the average thickness of the second surface coating layer is 0.53 μm and the average thickness of the first surface coating layer is 1.34 μm. (Average thickness 1.34 μm) / Second surface coating layer (Average thickness 0.53 μm) / Base material layer (15 μm) / Adhesive layer (3 μm) / Barrier layer (35 μm) / Adhesive layer (20 μm) / Heat A laminated body in which a fusing resin layer (20 μm) was laminated was obtained.

Comparative Example 1
By applying the resin composition forming the first surface coating layer twice by the gravure printing method without separating the composition of the first surface coating layer and the second surface coating layer, the average thickness of the surface coating layer can be adjusted. The surface coating layer (average thickness 2.53 μm) / base material layer (15 μm) / adhesive layer (3 μm) / barrier layer (in order from the outside) in the same manner as in Example 1 except that the thickness was 2.53 μm. A laminated body in which 35 μm) / adhesive layer (20 μm) / heat-sealing resin layer (20 μm) was laminated was obtained.

Comparative Example 2
By applying the resin composition forming the second surface coating layer twice by the gravure printing method without separating the composition of the first surface coating layer and the second surface coating layer, the average thickness of the surface coating layer can be obtained. The surface coating layer (average thickness 1.54 μm) / base material layer (15 μm) / adhesive layer (3 μm) / barrier layer (in order from the outside) in the same manner as in Example 1 except that the thickness was 1.54 μm. A laminated body in which 35 μm) / adhesive layer (20 μm) / heat-sealing resin layer (20 μm) was laminated was obtained.

<Average film thickness>
The average film thicknesses of the first surface coating layer and the second surface coating layer of the laminate constituting the exterior material for the power storage device were measured and calculated as follows, respectively. A cross-sectional image of the cross-section in the thickness direction of the laminate constituting the exterior material for the power storage device was acquired using a scanning electron microscope (SEM) under the conditions shown below. Next, with respect to the cross-sectional image, the cross-sectional areas of the first surface coating layer and the second surface coating layer were measured by image analysis, respectively. At this time, the horizontal length of the measurement area of the cross-sectional area (the length in the direction perpendicular to the thickness direction of the laminated body) was set to 25.4 μmm. Next, the average film thickness (μm) of the first surface coating layer and the second surface coating layer was calculated by dividing the obtained area by the lateral length (25.4 μm). When measuring and calculating the average film thickness of the surface coating layer (that is, the average film thickness of the first surface coating layer and the second surface coating layer combined), the first surface coating layer and the second surface in the same measurement area The area of the cross section of the coating layer is measured at the same time, and the obtained area is divided by the horizontal length (25.4 μm) of the measurement area to obtain the average film thickness (μm) of the average film thickness of the surface coating layer. Calculated.
(conditions)
Equipment: Hitachi High-Technologies S-4800
Acceleration voltage: 30kV
Emission current: 10 μA
Detector: Transmission electron detector Tilt: None Observation magnification: 5000 times Cross-section processing method:
The sample was cut into strips and embedded in resin. After the resin was cured, a rough cross section was prepared and surfaced. Then, it was stained with ruthenic acid for 2 to 3 hours, and an ultrathin section (thickness: about 100 nm) was prepared by a microtome. A diamond knife was used as the knife.

When particles having a particle diameter larger than the average thickness of the first surface coating layer in the cross-sectional image of the exterior material for the power storage device (measurement area length 25.4 μm) were observed, the first surface coating layer of Example 1 was observed. One particle having a diameter of 1.11 μm was observed, and one particle having a diameter of 1.47 μm was observed in the first surface coating layer of Example 2. Further, in the first surface coating layer of Comparative Example 1, particles having a particle size larger than the average thickness of the first surface coating layer were not observed, but particles having a diameter of 1.97 μm and 1.51 μm were observed as relatively large particles. Particles of 1.86 μm and the like were observed.

Further, with respect to the first surface coating layer of the exterior material for the power storage device of Example 1, a cross-sectional image was acquired using a scanning electron microscope (SEM) under the conditions shown below, and the particle size was approximately equal to or greater than the average film thickness. When the number of particles thought to be counted was counted, about 60 particles were present within a width of about 500 to 600 μm.
(SEM conditions)
Equipment: Hitachi High-Technologies S-4800
Acceleration voltage: 5kV
Emission current: 20 μA
Detector: Secondary electron detector Tilt: None Observation magnification: 5000 times Number of observations: 23 sheets Cross-section processing method: A sample was cut into strips and attached to a plastic plate with an adhesive. After the adhesive had dried, a cross section was prepared with a microtome. A diamond knife was used as the knife. In addition, the observation was performed about 5 times to damage the sample (damage caused by an electron beam), and then an image was acquired.

<Hardness measured by nanoindentation method in 23 ° C environment>
The hardness was measured using a nanoindenter (“TI950 TriboIndenter” manufactured by HYSITRON) as an apparatus. First, a Berkovich indenter (TI-0039) was used as an indenter of the nanoindenter. In an environment with a relative humidity of 50% and 23 ° C., the indenter is used on the surface to be measured (the surface on which the first surface coating layer or the second surface coating layer is exposed, and the thickness direction of each layer). The indenter was applied to the parallel surface) from the direction perpendicular to the thickness direction, and the indenter was pushed into the surface coating layer from the surface to a load of 50 μN over 10 seconds, held in that state for 5 seconds, and then unloaded over 10 seconds. The average value of N = 5 measured by shifting the measurement points was taken as the hardness. The results are shown in Table 1. The surface on which the indenter is pushed is cut in the thickness direction so as to pass through the center of the exterior material for the power storage device. This is a portion where the cross section of the first surface coating layer or the second surface coating layer to be measured is exposed. Further, in the measurement of the hardness of the first surface coating layer or the second surface coating layer, The place where the indenter is pushed is the part (resin part) where the particles are not present on the surface. In the measurement of the hardness of the particles of the first surface coating layer or the second surface coating layer, the particles are present on the surface. The cutting was performed using a commercially available rotary microtome.

The resin contained in the first surface coating layer is common to Examples 1 and 2 and Comparative Example 1, and the resin of the first surface coating layer of the exterior material for the power storage device of Examples 1 and 2 and Comparative Example 1 is used. The hardness was 218 MPa in each case.

The resin contained in the second surface coating layer is common to Examples 1 and 2 and Comparative Example 2, and the resin of the second surface coating layer of the exterior material for the power storage device of Examples 1 and 2 and Comparative Example 2 is used. The hardness was 23 MPa in each case.

Examples 1 and 2 and Comparative Examples 1 and 2 have common organic particles contained in the first surface coating layer or the second surface coating layer, and are used for the power storage devices of Examples 1 and 2 and Comparative Examples 1 and 2. The hardness of the organic particles of the exterior material was 496 MPa.

<Scratch resistance evaluation>
As the wear resistance evaluation device, a Gakushin type friction fastness tester AB-301 (manufactured by Tester Sangyo) was used. Place the exterior material for the power storage device on the table of the friction tester, and put a dry paper waste cloth (Kimwipe of Nippon Paper Crecia) on the tip of the arm (area 20 mm x 20 mm, R45 mm friction element: Masatsushi) at the top of the friction tester. I installed each. Next, the surface of the scratch-resistant layer of the exterior material for the power storage device was rubbed back and forth 200 times with a waste cloth. At this time, the condition of the reciprocating friction was a load of about 500 gf and one reciprocating / sec. The waste cloth was impregnated with 10 drops of ethanol, and 10 drops of ethanol were added to the waste cloth every 50 round trips. After the reciprocating friction was completed, the exterior material for the power storage device was removed from the wear resistance evaluation device, the state of the rubbed portion was visually confirmed, and the evaluation was performed using a monovalent evaluation standard. The results are shown in Table 1.
(Evaluation criteria)
A: No scratches were confirmed.
B: Scratches were confirmed, but the number of scratches was 10 or less.
C: More than 10 scratches were confirmed.

<Evaluation of the surface condition of the surface coating layer>
The surface of the surface coating layer was observed with a laser microscope (trade name VK-9710 manufactured by KEYENCE) from the outside of the exterior materials for each power storage device obtained in Examples and Comparative Examples. FIG. 4 shows a micrograph of the surface of the surface coating layer of the exterior material for the power storage device obtained in Example 1 (the photograph on the left is a photograph taken at a magnification of 10 times, and the photograph on the right is a photograph taken at a magnification of 20 times. It is a photograph taken in). FIG. 5 shows a micrograph of the surface of the surface coating layer of the exterior material for a power storage device obtained in Example 2 (the photograph on the left is a photograph taken at a magnification of 10 times, and the photograph on the right is a photograph taken at a magnification of 20 times. It is a photograph taken in). FIG. 6 shows a micrograph of the surface of the surface coating layer of the exterior material for a power storage device obtained in Comparative Example 1 (the photograph on the left is a photograph taken at a magnification of 10 times, and the photograph on the right is a photograph taken at a magnification of 20 times. It is a photograph taken in). FIG. 7 shows a micrograph of the surface of the surface coating layer of the exterior material for the power storage device obtained in Comparative Example 2 (the photograph on the left is a photograph taken at a magnification of 10 times, and the photograph on the right is a photograph taken at a magnification of 20 times. It is a photograph taken in). In addition, the surface condition of the surface coating layer was evaluated according to the following criteria, and the results are shown in Table 1.
(Evaluation criteria)
A: Traces of the gravure printing plate (white areas) are clearly and regularly arranged, and the surface condition of the surface coating layer is very uniform. B: Traces of the gravure printing plate (white areas) ), But the surface condition of the surface coating layer is low. C: No trace of gravure printing plate can be seen.

The exterior materials for power storage devices of Examples 1 and 2 are composed of a laminate having at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealing resin layer in this order from the outside. The surface coating layer includes a first surface coating layer and a second surface coating layer in this order from the outside, the first surface coating layer contains silica particles and a resin, and the second surface coating layer is silica. It contains inorganic particles and resin different from the particles, and the average thickness of the surface coating layer is 10 μm or less. It can be seen that the exterior materials for power storage devices of Examples 1 and 2 are excellent in scratch resistance and have high uniformity of the surface state of the surface coating layer.

As described above, the present disclosure provides the inventions of the following aspects.
Item 1. It is composed of a laminate having at least a surface coating layer, a base material layer, a barrier layer, and a thermosetting resin layer in this order from the outside.
The surface coating layer includes a first surface coating layer and a second surface coating layer in this order from the outside.
The first surface coating layer contains silica particles and a resin, and contains
The second surface coating layer contains inorganic particles different from the silica particles and a resin.
An exterior material for a power storage device, wherein the surface coating layer has an average film thickness of 10 μm or less.
Item 2. Item 2. The exterior material for a power storage device according to Item 1, wherein the first surface coating layer contains particles having a particle size larger than the average film thickness of the first surface coating layer.
Item 3. Item 2. The exterior material for a power storage device according to Item 1 or 2, wherein the second surface coating layer contains particles having a particle size larger than the average film thickness of the second surface coating layer.
Item 4. Regarding the cross section of the first surface coating layer and the second surface coating layer in the thickness direction, the particle size of the large particles observed with a scanning electron microscope is 1.0 μm or more and 5.0 μm or less, Item 2 or The exterior material for a power storage device according to 3.
Item 5. When the hardness of the large particles and the resin having a cross section in the thickness direction of the first surface coating layer was measured by the nanoindentation method in an environment of 23 ° C., the hardness of the large particles was the resin. Item 2. The exterior material for a power storage device according to any one of Items 2 to 4, which is larger than the hardness.
Item 6. Item 2. The exterior material for a power storage device according to any one of Items 2 to 5, wherein the difference between the hardness of the large particles and the hardness of the resin is 100 MPa or more.
Item 7. Item 2. The item 1 to item 2 to 6, wherein in an environment of 23 ° C., the hardness of the large particles having a cross section in the thickness direction of the first surface coating layer measured by a nanoindentation method is 400 MPa or more. Exterior material for power storage devices.
Item 8. Item 2. The exterior material for a power storage device according to any one of Items 2 to 7, wherein the large particles are organic particles.
Item 9. Item 2. The exterior material for a power storage device according to any one of Items 1 to 8, wherein the first surface coating layer and the second surface coating layer contain different resins.
Item 10. When the hardness of the first surface coating layer and the second surface coating layer in the thickness direction was measured by the nanoindentation method in an environment of 23 ° C., the hardness of the resin of the first surface coating layer was measured. Item 2. The exterior material for a power storage device according to any one of Items 1 to 9, wherein the hardness is larger than the hardness of the resin of the second surface coating layer.
Item 11. Item 10. The exterior material for a power storage device according to Item 10, wherein the difference between the hardness of the resin of the first surface coating layer and the hardness of the resin of the second surface coating layer is 100 MPa or more.
Item 12. Item 2. The storage storage according to any one of Items 1 to 11, wherein in a 23 ° C. environment, the hardness of the resin measured by the nanoindentation method with respect to the cross section in the thickness direction of the first surface coating layer is 150 MPa or more. Exterior material for devices.
Item 13. Item 2. The storage storage according to any one of Items 1 to 12, wherein in a 23 ° C. environment, the hardness of the resin measured by the nanoindentation method with respect to the cross section in the thickness direction of the second surface coating layer is 150 MPa or less. Exterior material for devices.
Item 14. Item 2. The exterior material for a power storage device according to any one of Items 1 to 13, wherein the average film thickness of the first surface coating layer is 2.5 μm or less.
Item 15. Item 2. The exterior material for a power storage device according to any one of Items 1 to 14, wherein the average film thickness of the second surface coating layer is 2.0 μm or less.
Item 16. Item 2. The exterior material for a power storage device according to any one of Items 1 to 15, wherein the inorganic particles contained in the second surface coating layer are inorganic particles having a larger specific gravity than the silica particles.
Item 17. Item 2. The exterior material for a power storage device according to any one of Items 1 to 16, wherein the inorganic particles contained in the second surface coating layer are barium sulfate.
Item 18. At least, it includes a step of obtaining a laminate in which a surface coating layer, a base material layer, a barrier layer, and a thermosetting resin layer are laminated in this order from the outside.
The surface coating layer includes a first surface coating layer and a second surface coating layer from the outside.
The first surface coating layer contains silica particles and a resin, and contains
The second surface coating layer contains inorganic particles different from the silica particles and a resin.
A method for manufacturing an exterior material for a power storage device, wherein the average film thickness of the surface coating layer is 10 μm or less.
Item 19. A power storage device in which a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the exterior material for the power storage device according to any one of Items 1 to 17.

1 Base material layer 2 Adhesive layer 3 Barrier layer 4 Heat-sealing resin layer 5 Adhesive layer 6 Second surface coating layer 7 First surface coating layer 10 Exterior material for power storage device 61 Inorganic particles 62,72 Organic particles 71 Silica particles

Claims (17)

It is composed of a laminate having at least a surface coating layer, a base material layer, a barrier layer, and a thermosetting resin layer in this order from the outside.
The surface coating layer includes a first surface coating layer and a second surface coating layer in this order from the outside.
The first surface coating layer contains silica particles and a resin, and contains
The second surface coating layer contains inorganic particles different from the silica particles and a resin.
The average thickness of the surface coating layer state, and are less 10 [mu] m,
Wherein the first surface coating layer, the that contains large particles having a particle diameter than the average film thickness of the first surface coating layer, the outer package for a power storage device. Wherein the second surface coating layer, the second and than the average thickness of the surface coating layer contains large particles having a particle size, exterior material for a power storage device according to claim 1. The thickness direction of the cross section of the first surface coating layer and the second surface coating layer, the particle size of the large particles observed with a scanning electron microscope, is 1.0μm or more 5.0μm or less, according to claim 1 Alternatively , the exterior material for a power storage device according to 2. When the hardness of the large particles and the resin having a cross section in the thickness direction of the first surface coating layer was measured by the nanoindentation method in an environment of 23 ° C., the hardness of the large particles was the resin. The exterior material for a power storage device according to any one of claims 1 to 3 , which is larger than the hardness. The exterior material for a power storage device according to any one of claims 1 to 4 , wherein the difference between the hardness of the large particles and the hardness of the resin is 100 MPa or more. According to any one of claims 1 to 5 , the hardness of the large particles having a cross section in the thickness direction of the first surface coating layer in an environment of 23 ° C. is 400 MPa or more as measured by the nanoindentation method. The exterior material for the power storage device described. The exterior material for a power storage device according to any one of claims 1 to 6 , wherein the large particles are organic particles. The exterior material for a power storage device according to any one of claims 1 to 7 , wherein the first surface coating layer and the second surface coating layer contain different resins. The exterior material for a power storage device according to claim 8 , wherein the difference between the hardness of the resin of the first surface coating layer and the hardness of the resin of the second surface coating layer is 100 MPa or more. The method according to any one of claims 1 to 9 , wherein the hardness of the resin measured by the nanoindentation method is 150 MPa or more with respect to the cross section of the first surface coating layer in the thickness direction in an environment of 23 ° C. Exterior material for power storage devices. The invention according to any one of claims 1 to 10 , wherein in a 23 ° C. environment, the hardness of the resin measured by the nanoindentation method with respect to the cross section in the thickness direction of the second surface coating layer is 150 MPa or less. Exterior material for power storage devices. The exterior material for a power storage device according to any one of claims 1 to 11 , wherein the average film thickness of the first surface coating layer is 2.5 μm or less. The exterior material for a power storage device according to any one of claims 1 to 12 , wherein the average film thickness of the second surface coating layer is 2.0 μm or less. The exterior material for a power storage device according to any one of claims 1 to 13 , wherein the inorganic particles contained in the second surface coating layer are inorganic particles having a larger specific gravity than the silica particles. The exterior material for a power storage device according to any one of claims 1 to 14 , wherein the inorganic particles contained in the second surface coating layer are barium sulfate. At least, it includes a step of obtaining a laminate in which a surface coating layer, a base material layer, a barrier layer, and a thermosetting resin layer are laminated in this order from the outside.
The surface coating layer includes a first surface coating layer and a second surface coating layer from the outside.
The first surface coating layer contains silica particles and a resin, and contains
The second surface coating layer contains inorganic particles different from the silica particles and a resin.
The average thickness of the surface coating layer state, and are less 10 [mu] m,
Wherein the first surface coating layer, the than the average thickness of the first surface coating layer that contains large particles having a particle size, production method of the outer package for a power storage device. A power storage device in which a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the exterior material for the power storage device according to any one of claims 1 to 15.

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