JP7635320B2 - Exterior materials for power storage devices - Google Patents

Description

The present invention relates to exterior materials for electricity storage devices, such as batteries and capacitors used in mobile devices such as smartphones and tablets, and batteries and capacitors used in hybrid vehicles, electric vehicles, wind power generation, solar power generation, and nighttime electricity storage, and to electricity storage devices exteriorized with the exterior materials.

In the claims and specification of this application, the term "center line average roughness (Ra)" refers to the center line average roughness (Ra) measured in accordance with JIS B0601-2001.

In addition, in the claims and specification of this application, the term "density" means the density measured in accordance with JIS K7112-1999 D method (density gradient tube method).

In addition, in the claims and specification of this application, the term "melt flow rate (MFR)" means the melt flow rate measured in accordance with JIS K7210-1-2014.

In addition, in this specification, the term "swell (percent)" refers to the room temperature die swell percentage (%) measured by the Capillary Rheometer A method as specified in JIS K7199-1999.

In recent years, as mobile electrical devices such as smartphones and tablet terminals have become thinner and lighter, a laminate consisting of a heat-resistant resin layer/adhesive layer/metal foil layer/adhesive layer/thermoplastic resin layer (inner sealant layer) is used as the exterior material of the lithium ion secondary battery, lithium polymer secondary battery, lithium ion capacitor, electric double layer capacitor, and other power storage devices mounted on these devices, instead of the conventional metal can. In addition, power sources for electric vehicles and the like, large power sources for power storage applications, capacitors, and the like are increasingly being exteriorized with a laminate (exterior material) of the above configuration. The laminate is molded into a three-dimensional shape such as a roughly rectangular parallelepiped shape by stretch molding or deep drawing. By molding into such a three-dimensional shape, it is possible to secure a storage space for accommodating the main body of the power storage device.

To form such a three-dimensional shape in a good condition without pinholes or breaks, it is necessary to improve the slipperiness of the surface of the inner sealant layer. As a laminate material for secondary battery containers that improves the slipperiness of the surface of the inner sealant layer to ensure good formability, a laminate material has been proposed in which an exterior resin film, a first adhesive layer, a chemically treated aluminum foil, a second adhesive layer, and a sealant film are laminated in that order, the sealant film being made of a random copolymer of propylene and an α-olefin with an α-olefin content of 2 to 10% by weight, and containing 1,000 to 5,000 ppm of a lubricant (see Patent Document 1).

JP 2003-288865 A

However, with the above-mentioned conventional technology, it is difficult to control the amount of surface lubricant precipitation depending on the heating and holding time and storage period during the production process of the exterior material (laminate material), and although the slipperiness during molding is good, the lubricant precipitates excessively on the surface, causing the lubricant to adhere and accumulate on the molding surface of the molding die when the exterior material is molded, resulting in the generation of white powder (white powder caused by the lubricant). When such white powder adheres and accumulates on the molding surface, it becomes difficult to perform good molding, so it becomes necessary to clean and remove the white powder every time it adheres and accumulates, but there is a problem that cleaning and removing this white powder reduces the productivity of the exterior material.

Of course, if the amount of lubricant added (lubricant content) is reduced, it is possible to suppress the adhesion and accumulation of white powder, but in this case, the amount of lubricant deposited on the surface is insufficient, resulting in a problem of poor moldability. Thus, in the past, it was difficult to achieve both excellent moldability and the suppression of the appearance of white powder on the surface of the exterior material.

The present invention has been made in view of this technical background, and aims to provide an exterior material for an electricity storage device, an exterior case for an electricity storage device, and an electricity storage device that ensure good slipperiness during molding, have excellent moldability, and are less likely to produce white powder on the surface.

To achieve the above objective, the present invention provides the following means:

[1] An exterior material for an electricity storage device, comprising a heat-resistant resin layer as an outer layer, a sealant layer as an inner layer, and a metal foil layer disposed between these layers,
The sealant layer is composed of one or more layers, and the innermost layer of the sealant layer contains a random copolymer containing propylene and other copolymer components excluding propylene as copolymer components, a surface-roughening material, and a lubricant;
The surface roughening material is made of particles containing a thermoplastic resin,
The outer casing material for an electricity storage device, wherein the center line average roughness Ra of the surface of the innermost layer is 0.05 μm to 1 μm.

[2] The exterior material for an electricity storage device according to the preceding paragraph 1, in which the thermoplastic resin constituting the surface-roughening material is a high-density polyethylene resin.

[3] The exterior material for an electricity storage device according to item 2, wherein the high-density polyethylene resin has a density of 0.935 g/cm ³ to 0.965 g/cm ³ and a melt flow rate at 190° C. of 0.01 g/10 min to 2 g/10 min.

[4] The exterior material for a storage battery device according to any one of paragraphs 1 to 3 above, in which the content of the surface roughening material in the innermost layer of the sealant layer is 1% by mass to 30% by mass, and the content of the lubricant in the innermost layer is greater than 0 ppm and not more than 1000 ppm.

[5] The exterior material for an electricity storage device according to any one of items 1 to 4 above, wherein the lubricant is one or more lubricants selected from the group consisting of fatty acid amides, waxes, silicones, and paraffins.

[6] The exterior material for an electricity storage device according to any one of items 1 to 5 above, wherein the sealant layer is made up of multiple layers.

[7] The sealant layer includes the innermost layer and a first intermediate layer laminated on a surface of the innermost layer facing the metal foil layer,
The first intermediate layer contains an elastomer-modified olefin-based resin,
The elastomer-modified olefin-based resin comprises an elastomer-modified homopolypropylene and/or an elastomer-modified random copolymer,
7. The exterior material for an electricity storage device according to item 6 above, wherein the elastomer-modified random copolymer is an elastomer-modified random copolymer containing, as copolymerization components, propylene and a copolymerization component other than propylene.

[8] The sealant layer includes the innermost layer, a first intermediate layer laminated on a surface of the innermost layer facing the metal foil layer, and a second intermediate layer laminated on a surface of the first intermediate layer facing the metal foil layer,
The first intermediate layer contains an elastomer-modified olefin-based resin,
The elastomer-modified olefin-based resin comprises an elastomer-modified homopolypropylene and/or an elastomer-modified random copolymer,
The elastomer-modified random copolymer is an elastomer-modified random copolymer containing propylene and other copolymer components other than propylene as copolymer components,
7. The exterior packaging material for an electricity storage device according to item 6 above, wherein the second intermediate layer contains a random copolymer containing propylene and a copolymer component other than propylene as a copolymer component.

[9] An exterior case for an electricity storage device, comprising a molded article of the exterior material for an electricity storage device described in any one of items 1 to 8 above.

[10] A main body of an electricity storage device;
An exterior member made of the exterior material for an electricity storage device according to any one of items 1 to 8 and/or the exterior case for an electricity storage device according to item 9,
The power storage device, wherein the power storage device main body is exteriorly covered with the exterior member.

In the invention of [1], the innermost layer of the sealant layer contains a random copolymer containing propylene and other copolymer components excluding propylene as copolymer components, a surface-roughening material, and a lubricant, and the surface-roughening material is made of particles containing a thermoplastic resin, and the center line average roughness Ra of the surface of the innermost layer is 0.05 μm to 1 μm, so that good slipperiness can be ensured during molding and excellent moldability is achieved. Furthermore, by using the surface-roughening material in combination with the lubricant (by using the surface-roughening material in combination, the amount of lubricant used can be reduced compared to conventional methods), the center line average roughness Ra of the surface of the innermost layer is set to 0.05 μm to 1 μm, so that white powder is unlikely to appear on the surface 7a of the innermost layer of the sealant layer of the exterior material. Since white powder is unlikely to appear in this way, the productivity of the exterior material can be improved, and sufficient sealing can be ensured in the heat-sealed portion after the sealant layers are heat-sealed to each other. In addition, by using the surface-roughening material in this way, the amount of lubricant used can be reduced compared to conventional methods, which means that, for example, when performing an aging process, there is no need to adjust the amount of lubricant bleed-out, making the aging process unnecessary or possible to complete the aging process in a short period of time, thereby further improving the productivity of the exterior material. In addition, since the surface-roughening material is made of particles containing a thermoplastic resin, clogging of the filter during processing of the resin for the innermost layer can be reduced, further improving productivity. Furthermore, since the surface-roughening material is made of particles containing a thermoplastic resin, it does not sink into the interior or fall off when pressure is applied from the outside, unlike silica particles.

In the invention of [2], the thermoplastic resin constituting the roughening material is a high-density polyethylene resin, and since the compatibility of the high-density polyethylene resin with the random copolymer is appropriately low, the surface can be effectively roughened, and the slipperiness can be further improved.

The invention [3] can further improve the slipperiness during molding, thereby further improving moldability.

In the invention of [4], by setting the content of the roughening material in the innermost layer to 1% by mass to 30% by mass, excellent moldability can be ensured even if the content of the lubricant in the innermost layer is 1000 ppm or less. In addition, since the content of the lubricant in the innermost layer is more than 0 ppm and less than 1000 ppm, it becomes even more difficult for white powder to appear on the surface of the innermost layer of the sealant layer of the exterior material. Furthermore, since the content of the lubricant in the innermost layer is more than 0 ppm and less than 1000 ppm, the amount of lubricant present on the surface of the innermost layer of the exterior material can be stabilized even during storage (for example, fluctuations in the amount of lubricant present on the surface of the innermost layer due to long-term storage can be suppressed), and stable and excellent moldability can be ensured.

In the invention of [5], one or more lubricants selected from the group consisting of fatty acid amides, wax, silicone, and paraffin are used as the lubricant, so that even better slip properties can be ensured during molding, and even better moldability can be ensured.

In the invention of [6], the sealant layer is composed of multiple layers, and by laminating one or more layers on the surface of the innermost layer facing the metal foil layer, it is possible to further improve the adhesive strength between the sealant layer and the metal foil layer, for example.

In the invention [7], the sealant layer includes an innermost layer and a first intermediate layer of the above-mentioned specific configuration laminated on the surface of the innermost layer facing the metal foil layer, so that whitening of the sealant layer during molding can be sufficiently suppressed and sufficient sealing performance can be ensured when heat-sealed.

In the invention of [8], the sealant layer includes an innermost layer, a first intermediate layer of the specific configuration laminated on the surface of the innermost layer facing the metal foil layer, and a second intermediate layer of the specific configuration laminated on the surface of the first intermediate layer facing the metal foil layer. In addition to being able to enjoy the effects of the invention of [7], the adhesive strength between the sealant layer and the metal foil layer can be further improved and sufficient insulation can be ensured.

The invention [9] provides an exterior case for an electricity storage device that is well molded and is less likely to produce white powder on the surface of the exterior case (the surface of the innermost layer of the sealant layer).

The invention [10] provides an electricity storage device that is packaged with an exterior material for electricity storage devices and/or an exterior case that is well molded and that is less likely to produce white powder on the surface (the surface of the innermost layer of the sealant layer).

1 is a cross-sectional view showing a first embodiment of an exterior material for an electricity storage device according to the present invention. FIG. 2 is a cross-sectional view showing a second embodiment of an exterior material for an electricity storage device according to the present invention. FIG. 4 is a cross-sectional view showing a third embodiment of an exterior material for an electricity storage device according to the present invention. 1 is a cross-sectional view showing one embodiment of an electricity storage device according to the present invention. 5 is a perspective view showing the exterior material (planar), the main body of the electricity storage device, and the exterior case (a molded body molded into a three-dimensional shape) constituting the electricity storage device of FIG. 4 in a separated state before being heat-sealed.

The exterior material 1 for an electric storage device according to the present invention includes a heat-resistant resin layer 2 as an outer layer, a sealant layer 3 as an inner layer, and a metal foil layer 4 disposed between these two layers, the sealant layer 3 being composed of one or more layers, the innermost layer 7 of the sealant layer 3 containing a random copolymer containing propylene and other copolymer components excluding propylene as copolymer components, a surface-roughening material, and a lubricant, the surface-roughening material being composed of particles containing a thermoplastic resin, and the center line average roughness Ra of the surface 7a of the innermost layer 7 being 0.05 μm to 1 μm.

Three embodiments of the exterior material 1 for an electricity storage device according to the present invention are shown in Figures 1 to 3. These three embodiments are merely representative embodiments, and the present invention is not limited to these configurations.

The exterior packaging material 1 for an electricity storage device shown in Figures 1 to 3 is configured such that a heat-resistant resin layer (outer layer) 2 is laminated and integrated onto one surface (upper surface) of a metal foil layer 4 via a second adhesive layer (outer adhesive layer) 5, and a sealant layer (inner layer) 3 is laminated and integrated onto the other surface (lower surface) of the metal foil layer 4 via a first adhesive layer (inner adhesive layer) 6.

In the exterior packaging material 1 for an electrical storage device shown in FIG. 1, the sealant layer (inner layer) 3 is composed of the innermost layer 7 and a first intermediate layer 8 laminated on the surface of the innermost layer 7 facing the metal foil layer 4. That is, the first intermediate layer 8 is laminated on the other surface (lower surface) of the metal foil layer 4 via a first adhesive layer (inner adhesive layer) 6, and the innermost layer 7 is laminated on the surface (lower surface) of the first intermediate layer 8. The innermost layer 7 is exposed on the inside surface of the exterior packaging material 1 (see FIG. 1).

In the electrical storage device exterior material 1 shown in FIG. 2, the sealant layer (inner layer) 3 is composed of the innermost layer 7, a first intermediate layer 8 laminated on the surface of the innermost layer 7 facing the metal foil layer 4, and a second intermediate layer 9 laminated on the surface of the first intermediate layer 8 facing the metal foil layer 4. That is, the second intermediate layer 9 is laminated on the other surface (lower surface) of the metal foil layer 4 via a first adhesive layer (inner adhesive layer) 6, the first intermediate layer 8 is laminated on the surface (lower surface) of the second intermediate layer 9, and the innermost layer 7 is laminated on the surface (lower surface) of the first intermediate layer 8. The innermost layer 7 is exposed to the inner surface of the exterior material 1 (see FIG. 2).

In the exterior packaging material 1 for an electrical storage device shown in FIG. 3, the sealant layer (inner layer) 3 is made of the innermost layer 7. That is, the sealant layer 3 made of the innermost layer 7 is laminated on the other surface (lower surface) of the metal foil layer 4 via a first adhesive layer (inner adhesive layer) 6. The innermost layer 7 is exposed on the inner surface of the exterior packaging material 1 (see FIG. 3).

In the present invention, the sealant layer (inner layer) 3 provides excellent chemical resistance against highly corrosive electrolytes used in lithium ion secondary batteries and the like, and also serves to impart heat sealability to the exterior material.

In the present invention, the innermost layer 7 of the sealant layer 3 is configured to contain a random copolymer containing propylene and other copolymer components excluding propylene as copolymer components, a surface roughening material, and a lubricant.

The random copolymer contains "propylene" and "other copolymer components other than propylene" as copolymerization components. Regarding the random copolymer, the "other copolymer components other than propylene" are not particularly limited, but examples thereof include olefin components such as ethylene, 1-butene, 1-hexene, 1-pentene, and 4-methyl-1-pentene, as well as butadiene.

The random copolymer (a random copolymer containing propylene and other copolymer components other than propylene as copolymerization components) preferably has a melt flow rate (MFR) at 230°C in the range of 1g/10 min to 10g/10 min. By using the random copolymer having an MFR in the range of 1g/10 min to 10g/10 min, the roughening material can be finely and uniformly dispersed, and the sealing property when sealing the main body of the electric storage device in the exterior material is improved to obtain sufficient heat seal strength, and the reduction in the thickness of the sealant layer after heat sealing can be suppressed, thereby further improving the insulation. When an ethylene-propylene random copolymer is used as the random copolymer, the ethylene content in the random copolymer is preferably 3% by mass to 7% by mass. In this case, high heat seal strength can be obtained even when heat sealing is performed at a relatively low heat seal temperature of about 200°C. In addition, the melting point of the random copolymer is preferably in the range of 140°C to 155°C.

The surface roughening material is not particularly limited, but examples thereof include thermoplastic resin-containing pellets and thermoplastic resin-containing powders. Among these, thermoplastic resin-containing powders are preferred in terms of dispersibility. The thermoplastic resin constituting the surface roughening material is not particularly limited, but examples thereof include high-density polyethylene resin, low-density polyethylene resin, ethylene-olefin (olefins other than ethylene) copolymer resin, ethylene-vinyl ester copolymer resin, polystyrene resin, and the like. Among these, it is preferable to use a surface roughening material containing high-density polyethylene resin, and in this case, the surface 7a of the innermost layer 7 of the sealant layer can be effectively roughened without impairing the heat sealability, and the slipperiness can be further improved.

In the matrix of the random copolymer constituting the innermost layer 7, the roughening material particles, which have low compatibility with the matrix, are dispersed, and the roughening material particles are partially exposed (protruding) on the surface 7a of the innermost layer 7, forming unevenness on the surface 7a (roughening the surface). For example, by mixing the random copolymer pellets or powder with thermoplastic resin pellets or thermoplastic resin powder as the roughening material, melt-kneading the mixture in an extruder or the like to finely disperse it, and then cooling and solidifying it, the surface 7a of the innermost layer 7 having unevenness formed thereon (roughening the surface) can be obtained.

The average particle size of the roughening agent in the dispersed state is preferably in the range of 0.05 μm to 10 μm, in which case the slipperiness can be further improved.

The density of the high density polyethylene resin (HDPE) constituting the surface-roughening material is preferably in the range of 0.935 g/cm ³ to 0.965 g/cm ^3. When the density is in this range, the slipperiness can be further improved, and the moldability can be further improved. In particular, the density of the high density polyethylene resin (HDPE) constituting the surface-roughening material is more preferably in the range of 0.945 g/cm ³ to 0.960 g/cm ³ .

The density of the high-density polyethylene resin can be adjusted by changing the content of the comonomer (copolymerization component). Examples of such comonomers include unsaturated olefins other than ethylene, such as 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene, but are not limited to these. As the comonomer, it is preferable to use at least one comonomer selected from the group consisting of 1-butene and 1-hexene.

It is preferable that the melt flow rate (MFR) at 190°C of the high-density polyethylene resin constituting the surface roughening material is in the range of 0.01g/10min to 2g/10min. By having an MFR of "0.01g/10min" or more, the surface roughening material can be finely and uniformly dispersed in the random copolymer, and by having an MFR of "2g/10min" or less, the surface roughness can be increased, further improving the slipperiness. In particular, it is preferable that the melt flow rate (MFR) at 190°C of the high-density polyethylene resin (HDPE) constituting the surface roughening material is in the range of 0.1g/10min to 1g/10min.

The melt flow rate (MFR) of the high-density polyethylene resin can be adjusted, for example, as follows. When the high-density polyethylene resin is produced using a Phillips catalyst, the MFR of the high-density polyethylene resin can be adjusted by changing the reactor temperature during polymerization, or by adding a small amount of hydrogen and then changing the reactor temperature. When the high-density polyethylene resin is produced using a Ziegler catalyst, the MFR of the high-density polyethylene resin can be adjusted by changing the amount of hydrogen supplied to the reactor during polymerization. When the Phillips catalyst is used, the high-density polyethylene resin can be produced by slurry polymerization using isobutane as a solvent, but the method is not particularly limited to these methods.

The melting point of the high-density polyethylene resin constituting the roughening material is preferably in the range of 130°C to 145°C. The high-density polyethylene resin is also preferably one that has a long-chain branch (having 10 or more carbon atoms). When a high-density polyethylene resin with a long-chain branch is used, roughening material particles are easily formed when the roughening material is melt-kneaded with the random copolymer, so that the surface 7a of the innermost layer can be more effectively roughened and the slipperiness can be further improved.

The swell of the high-density polyethylene resin constituting the roughening material is preferably in the range of 25% to 55%. In this case, the melt viscoelasticity of the resin constituting the roughening material is relatively high, making it easier to form particles of high-density polyethylene resin, and the surface 7a of the innermost layer can be more effectively roughened, further improving slipperiness. In particular, the swell of the high-density polyethylene resin constituting the roughening material is more preferably in the range of 35% to 45%.

The "swell" refers to the room temperature die swell percentage (%) measured by the Capillary Rheometer A method defined in JIS K7199-1999. Using a standard die (hole diameter: 2.095 mm, length: 8 mm) defined in JIS K7210-1-2014, a strand of resin (string-like resin) extruded from a capillary die at a temperature of 190°C under a load of 2.16 kg was collected with tweezers when the strand reached a length of 2 cm. After natural cooling and solidification, the diameter of the strand was measured with a micrometer at a point 1 cm from the tip. This measured value was taken as D1 (mm).
Swell (%) = {(D1 - D0)/D0)} x 100
D1: diameter of extruded resin
D0: Standard die hole diameter (2.095mm)
This is the value (%) calculated using the above formula.

The high load swell (swell when a load of 21.6 kg) of the high density polyethylene resin that constitutes the roughening material is preferably in the range of 55% to 90%. In this case, the melt viscoelasticity of the resin that constitutes the roughening material is relatively high, making it easier to form particles of high density polyethylene resin, and the surface 7a of the innermost layer can be more effectively roughened, further improving slipperiness.

The high load swell is measured in accordance with JIS K7199-1999 using a standard die (hole diameter: 2.095 mm, length: 8 mm) specified in JIS K7210-1-2014, at a temperature of 190° C. and a load of 21.6 kg. When a strand (string-like resin) of resin extruded from a capillary die reaches a length of 2 cm, the strand is collected with tweezers, and after natural cooling and solidification, the diameter of the strand 1 cm from the tip is measured with a micrometer. When this measured value is taken as D2 (mm),
High load swell (%) = {(D2 - D0)/D0)} x 100
D2: diameter of extruded resin
D0: Standard die hole diameter (2.095mm)
This is the value calculated using the above formula.

The "high load MFR (MFR at a load of 21.6 kg)/MFR (MFR at a load of 2.16 kg)" of the high-density polyethylene resin constituting the roughening material is preferably in the range of 25 to 40. In this case, compatibility between the random copolymer and the roughening material can be ensured to a certain extent, and whitening of the sealant layer 3 during molding can be further suppressed.

The difference between the melt density of the roughening material and the density of the roughening material is preferably in the range of 0.15 g/cm ³ to 0.25 g/cm ^3. In this case, the volumetric shrinkage rate of the roughening material increases as the mixed resin cools and solidifies from the molten state, so that the surface 7a of the innermost layer 7 can be efficiently roughened and the center line average roughness Ra of the surface 7a of the innermost layer 7 can be easily adjusted to 0.05 μm to 1 μm.

In the innermost layer 7 of the sealant layer, the difference between the density of the random copolymer (a random copolymer containing propylene and other copolymer components other than propylene as copolymer components) and the density of the roughening material is preferably in the range of 0.04 g/ ^cm3 to 0.07 g/ ^cm3.In this case, the difference in volume shrinkage rate between the random copolymer and the roughening material becomes large as the mixed resin in the molten state cools and solidifies, so that the unevenness of the surface 7a of the innermost layer becomes large, allowing the surface 7a of the innermost layer to be roughened more effectively and further improving the slipperiness.

In addition, it is preferable that the difference between the melt density of the random copolymer (a random copolymer containing propylene and other copolymer components other than propylene as copolymer components) and the melt density of the surface roughening material is 0.3 g/ ^cm3 or less.

The surface roughening material content in the innermost layer 7 of the sealant layer is preferably set to 1% to 30% by mass, and in this case, excellent moldability can be ensured even if the lubricant content in the innermost layer 7 is 1000 ppm or less. Furthermore, by having the lubricant content in the innermost layer 7 exceed 0 ppm and be 1000 ppm or less, it becomes even more difficult for white powder to appear on the surface 7a of the innermost layer 7 of the sealant layer of the exterior material. In particular, it is particularly preferable that the surface roughening material content in the innermost layer 7 of the sealant layer be set to 1% to 20% by mass. Furthermore, it is preferable that the lubricant content in the innermost layer 7 be set to be more than 0 ppm and be 900 ppm or less, and more preferably be set to be 10 ppm to 600 ppm.

The lubricant is not particularly limited, but it is preferable to use one or more lubricants selected from the group consisting of fatty acid amides, waxes, silicones, and paraffins. Among them, it is particularly preferable to use fatty acid amides as the lubricant. The fatty acid amides are not particularly limited, but examples thereof include erucic acid amide, behenic acid amide, etc.

In the present invention, an antiblocking agent may be contained in the innermost layer 7 as long as it does not impair the effects of the present invention (see Example 10).

In the present invention, the center line average roughness Ra of the surface 7a of the innermost layer 7 is set to 0.05 μm to 1 μm, and it is particularly preferable that the center line average roughness Ra of the surface 7a of the innermost layer 7 is set to 0.1 μm to 1 μm. In addition, it is preferable that the thickness of the innermost layer 7 is set to 2 μm to 40 μm.

When the sealant layer 3 has the first intermediate layer 8, it is preferable to use an elastomer-modified olefin-based resin as the resin constituting the first intermediate layer 8. The elastomer-modified olefin-based resin (polypropylene block copolymer) is preferably made of elastomer-modified homopolypropylene and/or elastomer-modified random copolymer. The elastomer-modified random copolymer is an elastomer-modified random copolymer containing "propylene" and "other copolymer components other than propylene" as copolymer components, and the "other copolymer components other than propylene" are not particularly limited, but examples thereof include olefin components such as ethylene, 1-butene, 1-hexene, 1-pentene, 4-methyl-1-pentene, and butadiene. The elastomer is not particularly limited, but it is preferable to use an olefin-based thermoplastic elastomer. The olefin-based thermoplastic elastomer is not particularly limited, but examples include EPR (ethylene propylene rubber), propylene-butene elastomer, propylene-butene-ethylene elastomer, EPDM (ethylene-propylene-diene rubber), etc., and among these, it is preferable to use EPR (ethylene propylene rubber).

Regarding the elastomer-modified olefin-based resin, the "elastomer-modified" form may be one in which an elastomer is graft-polymerized, or one in which an elastomer is added to an olefin-based resin (homopolypropylene and/or the random copolymer), or another modified form may be used.

When the sealant layer 3 has the first intermediate layer 8, it is preferable that the first intermediate layer 8 contains a lubricant. Examples of the lubricant include the same lubricant as those exemplified as the lubricant contained in the innermost layer 7. It is preferable that the thickness of the first intermediate layer 8 is set to 10 μm to 60 μm.

When the sealant layer 3 has the second intermediate layer 9, it is preferable to use a random copolymer containing "propylene" and "other copolymer components other than propylene" as the copolymerization components for the resin constituting the second intermediate layer 9. Regarding the random copolymer, the "other copolymer components other than propylene" are not particularly limited, but examples thereof include olefin components such as ethylene, 1-butene, 1-hexene, 1-pentene, and 4-methyl-1-pentene, as well as butadiene.

When the sealant layer 3 has the second intermediate layer 9, it is preferable that the second intermediate layer 9 contains a lubricant. Examples of the lubricant include the same lubricant as those exemplified as the lubricant contained in the innermost layer 7. It is also preferable that the thickness of the second intermediate layer 9 is set to 2 μm to 40 μm.

In the present invention, the heat-resistant resin constituting the heat-resistant resin layer (outer layer) 2 is a heat-resistant resin that does not melt at the heat-sealing temperature when the exterior material is heat-sealed. As the heat-resistant resin, it is preferable to use a heat-resistant resin having a melting point 10°C or more higher than the melting point of the sealant layer 3, and it is particularly preferable to use a heat-resistant resin having a melting point 20°C or more higher than the melting point of the sealant layer 3.

The heat-resistant resin layer (outer layer) 2 is not particularly limited, but examples thereof include polyamide films such as nylon films, polyester films, etc., and these stretched films are preferably used. Among them, it is particularly preferable to use biaxially stretched polyamide films such as biaxially stretched nylon films, biaxially stretched polybutylene terephthalate (PBT) films, biaxially stretched polyethylene terephthalate (PET) films, or biaxially stretched polyethylene naphthalate (PEN) films as the heat-resistant resin layer 2. The nylon film is not particularly limited, but examples thereof include nylon 6 film, nylon 6,6 film, and MXD nylon film. The heat-resistant resin layer 2 may be formed as a single layer, or may be formed as a multilayer of polyester film/polyamide film (e.g., a multilayer of PET film/nylon film). In the case of the multilayer, it is preferable to place the polyester film side on the outermost side.

The thickness of the outer layer 2 is preferably 2 μm to 50 μm. When a polyester film is used, the thickness is preferably 5 μm to 40 μm, and when a nylon film is used, the thickness is preferably 15 μm to 50 μm. By setting the thickness to above the above preferred lower limit, sufficient strength as an exterior material can be ensured, and by setting the thickness to below the above preferred upper limit, stress during molding such as stretch molding and drawing can be reduced, improving moldability.

In the present invention, the metal foil layer 4 plays a role in imparting gas barrier properties to the exterior material 1 to prevent the intrusion of oxygen and moisture. The metal foil layer 4 is not particularly limited, but examples thereof include aluminum foil, SUS foil (stainless steel foil), copper foil, nickel foil, etc., and among these, it is preferable to use aluminum foil. The thickness of the metal foil layer 4 is preferably 15 μm to 100 μm. By having a thickness of 15 μm or more, it is possible to prevent the occurrence of pinholes during rolling when manufacturing the metal foil, and by having a thickness of 100 μm or less, it is possible to reduce stress during molding such as stretch molding and drawing molding, thereby improving formability. Among these, it is more preferable that the thickness of the metal foil layer 4 is 15 μm to 45 μm. In addition, as the aluminum foil, A8079-O material and A8021-O material specified in JIS H4160:2006 are suitable.

It is preferable that at least the inner surface (the surface on the second adhesive layer 6 side) of the metal foil layer 4 is subjected to a chemical conversion treatment. By applying such a chemical conversion treatment, corrosion of the metal foil surface due to the contents (such as the electrolyte of a battery) can be sufficiently prevented. Examples of such chemical conversion treatments include chromate treatment.

The first adhesive layer (outer adhesive layer) 5 is not particularly limited, but examples thereof include a polyurethane polyolefin adhesive layer, a polyurethane adhesive layer, a polyester polyurethane adhesive layer, and a polyether polyurethane adhesive layer. The thickness of the first adhesive layer 5 is preferably set to 1 μm to 6 μm.

The second adhesive layer (inner adhesive layer) 6 is not particularly limited, and may be, for example, one of the adhesives exemplified above as the first adhesive layer 5. However, it is preferable to use a polyolefin adhesive that swells less with the electrolyte. Among them, it is particularly preferable to use an acid-modified polyolefin adhesive. Examples of the acid-modified polyolefin adhesive include maleic acid-modified polypropylene adhesive and fumaric acid-modified polypropylene adhesive. The thickness of the second adhesive layer 6 is preferably set to 1 μm to 5 μm.

In the present invention, by providing the above-mentioned configuration, the amount of lubricant present (adhered) to the surface 7a of the innermost layer 7 of the sealant layer 3 is preferably in the range of 0.1 μg/ ^cm2 to 0.6 μg/ ^cm2 . Of these, the amount of lubricant present on the surface 7a of the innermost layer 7 is more preferably in the range of 0.1 μg/ ^cm2 to 0.3 μg/ ^cm2 .

Furthermore, in the present invention, by virtue of the above-mentioned configuration, the amount of lubricant present (adhered) on the surface (outer surface) of the outer layer 2 is preferably in the range of 0.1 μg/cm ² to 0.6 μg/cm ^2. Of these, the amount of lubricant present on the surface of the outer layer 2 is more preferably in the range of 0.1 μg/cm ² to 0.3 μg/cm ² .

In addition, in the present invention, by having the above configuration, it is preferable that the dynamic friction coefficient of the surface 7a of the innermost layer 7 of the sealant layer 3 is 0.3 or less.

By molding (deep drawing, stretch molding, etc.) the exterior material 1 for an electricity storage device of the present invention, an exterior case 10 for an electricity storage device can be obtained (see FIG. 5). Note that the exterior material 1 of the present invention can also be used as is without being subjected to molding (see FIG. 5).

FIG. 4 shows an embodiment of an electric storage device 30 constructed using the exterior material 1 of the present invention. This electric storage device 30 is a lithium ion secondary battery. In this embodiment, as shown in FIGS. 4 and 5, an exterior member 15 is constructed by a case 10 obtained by molding the exterior material 1 and a planar exterior material 1 that was not used for molding. Thus, a substantially rectangular parallelepiped electric storage device main body (electrochemical element, etc.) 31 is accommodated in the accommodation recess of the exterior case 10 obtained by molding the exterior material 1 of the present invention, and the exterior material 1 of the present invention is placed on the electric storage device main body 31 with its inner layer 3 side facing inward (lower side) without being molded, and the peripheral portion of the inner layer 3 of the planar exterior material 1 and the inner layer 3 of the flange portion (sealing peripheral portion) 29 of the exterior case 10 are sealed and sealed by heat sealing to construct the electric storage device 30 of the present invention (see FIGS. 4 and 5). The inner surface of the storage recess of the exterior case 10 is an inner layer (sealant layer) 3, and the outer surface of the storage recess is an outer layer (heat-resistant resin layer) 2 (see Figure 5).

In FIG. 4, 39 is a heat seal portion where the peripheral portion of the exterior material 1 and the flange portion (sealing peripheral portion) 29 of the exterior case 10 are joined (fused). In the electricity storage device 30, the tip of the tab lead connected to the electricity storage device main body 31 is led out to the outside of the exterior member 15, but is not shown in the figure.

The electric storage device main body 31 is not particularly limited, but examples thereof include a battery main body, a capacitor main body, a condenser main body, etc.

The width of the heat-sealed portion 39 is preferably set to 0.5 mm or more. By setting the width at 0.5 mm or more, sealing can be performed reliably. In particular, the width of the heat-sealed portion 39 is preferably set to 3 mm to 15 mm.

In the above embodiment, the exterior member 15 is configured to include an exterior case 10 obtained by molding the exterior material 1 and a planar exterior material 1 (see Figures 4 and 5), but is not limited to this combination. For example, the exterior member 15 may be configured to include a pair of exterior materials 1, or a pair of exterior cases 10.

Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.

Example 1
A chemical conversion coating was formed by applying a chemical conversion treatment solution consisting of phosphoric acid, polyacrylic acid (acrylic resin), a chromium (III) salt compound, water, and alcohol to both sides of an aluminum foil 4 having a thickness of 40 μm, and then drying at 180° C. The chromium deposition amount of this chemical conversion coating was 10 mg/ ^m2 per side.

Next, a 25 μm-thick biaxially oriented 6 nylon film 2 was dry laminated (attached) to one side of the chemically treated aluminum foil 4 via a two-component curing urethane adhesive 5.

Next, a second intermediate layer film (second intermediate layer) 9 having a thickness of 6 μm containing an ethylene-propylene random copolymer and 500 ppm of erucic acid amide, a first intermediate layer film (first intermediate layer) 8 having a thickness of 28 μm containing an elastomer-modified olefin resin (block PP) and 500 ppm of erucic acid amide, and an innermost layer film (innermost layer) 7 having a thickness of 6 μm containing an ethylene-propylene random copolymer, 1.0 mass% high-density polyethylene resin powder (surface-roughening material), and 500 ppm of erucic acid amide are co-extruded using a T-die so that the three layers are laminated in this order. After obtaining a sealant film (second intermediate layer film 9/first intermediate layer film 8/innermost layer film 7) 3 having a thickness of 40 μm, the second intermediate layer film 9 side of the sealant film 3 was superimposed on the other side of the aluminum foil 4 after the dry lamination via a two-liquid curing type maleic acid modified polypropylene adhesive 6, and dry laminated by sandwiching and pressing between a rubber nip roll and a laminating roll heated to 100 ° C., and then aging (heating) at 40 ° C. for 10 days to obtain an exterior material for a storage battery device 1 having the configuration shown in FIG. 2. The center line average roughness Ra of the surface 7a of the innermost layer 7 of the sealant layer 3 of the obtained exterior material for a storage battery device 1 was 0.13 μm.

The two-component curing maleic acid-modified polypropylene adhesive used was an adhesive solution containing 100 parts by mass of maleic acid-modified polypropylene (melting point 80°C, acid value 10 mgKOH/g) as a main agent, 8 parts by mass of an isocyanurate of hexamethylene diisocyanate (NCO content: 20% by mass) as a curing agent, and a solvent. The adhesive solution was applied to the other side of the aluminum foil 4 so that the solid application amount was 2 g/ ^m2 , and the adhesive solution was heated and dried, and then superimposed on the second intermediate layer film 9 side of the sealant film 3.

The high-density polyethylene resin (roughened surface material) has an MFR of 0.2 g/10 min at 190° C., a density of 0.963 g/cm ³ , and a swell of 40%, and is produced by the slurry loop process using a Phillips catalyst.

Example 2
An exterior material for a power storage device 1 having the configuration shown in Figure 2 was obtained in the same manner as in Example 1, except that the content of the high-density polyethylene resin (surface-roughening material) in the innermost layer film (innermost layer) 7 was changed from 1.0 mass% to 5.0 mass%.

Example 3
An outer casing material 1 for an electricity storage device having the configuration shown in Figure 2 was obtained in the same manner as in Example 2, except that behenic acid amide was used instead of erucic acid amide as the lubricant contained in the second intermediate layer film 9, the first intermediate layer film 8 and the innermost layer film 7.

Example 4
An outer casing material for an electricity storage device 1 having the configuration shown in FIG. 2 was obtained in the same manner as in Example 2, except that the content of erucamide in the innermost layer film (innermost layer) 7 was changed from 500 ppm to 1000 ppm.

Example 5
An exterior material 1 for a power storage device having the configuration shown in Figure 2 was obtained in the same manner as in Example 1, except that the content of the high-density polyethylene resin (surface-roughening material) in the innermost layer film (innermost layer) 7 was changed from 1.0 mass% to 10.0 mass%.

Example 6
An exterior material 1 for a power storage device having the configuration shown in FIG. 2 was obtained in the same manner as in Example 1, except that the content of the high-density polyethylene resin (surface-roughening material) in the innermost layer film (innermost layer) 7 was changed from 1.0% by mass to 15.0% by mass.

Example 7
An exterior material 1 for a power storage device having the configuration shown in FIG. 2 was obtained in the same manner as in Example 1, except that the content of the high-density polyethylene resin (surface-roughening material) in the innermost layer film (innermost layer) 7 was changed from 1.0% by mass to 20.0% by mass.

Example 8
An exterior material 1 for a power storage device having the configuration shown in Figure 2 was obtained in the same manner as in Example 1, except that the content of the high-density polyethylene resin (surface-roughening material) in the innermost layer film (innermost layer) 7 was changed from 1.0 mass% to 30.0 mass%.

<Example 9>
An exterior material 1 for a power storage device having the configuration shown in FIG. 2 was obtained in the same manner as in Example 1, except that the content of the high-density polyethylene resin (surface-roughening material) in the innermost layer film (innermost layer) 7 was changed from 1.0% by mass to 35.0% by mass.

Example 10
An outer casing material for an electricity storage device 1 having the configuration shown in FIG. 2 was obtained in the same manner as in Example 3, except that 2500 ppm of acrylic beads were further contained as an antiblocking agent (AB agent) in the innermost layer film (innermost layer) 7.

Example 11
An outer casing material 1 for an electricity storage device having the configuration shown in Figure 2 was obtained in the same manner as in Example 4, except that the high-density polyethylene resin (roughened surface material) contained in the innermost layer film (innermost layer) ⁷ had an MFR of 0.2 g/10 min, a density of 0.945 g/cm3, a swell ratio of 35, and was produced by the slurry loop method using a Phillips catalyst.

Example 12
An outer casing material 1 for an electricity storage device having the configuration shown in Figure 2 was obtained in the same manner as in Example 5, except that the high-density polyethylene resin (roughened surface material) contained in the innermost layer film (innermost layer) ⁷ had an MFR of 0.2 g/10 min, a density of 0.955 g/cm3, a swell ratio of 45, and was produced by the slurry loop method using a Phillips catalyst.

Example 13
An outer casing material 1 for an electricity storage device having the configuration shown in Figure 2 was obtained in the same manner as in Example 6, except that the high-density polyethylene resin (roughening material) contained in the innermost layer film (innermost layer) ⁷ had an MFR of 2 g/10 min at 190°C, a density of 0.954 g/cm3, a swell ratio of 30, and was produced by the slurry loop method using a Ziegler catalyst.

<Example 14>
An outer casing material 1 for an electricity storage device having the configuration shown in Figure 2 was obtained in the same manner as in Example 7, except that the high-density polyethylene resin (roughening material) contained in the innermost layer film (innermost layer) ⁷ had an MFR of 3 g/10 min at 190°C, a density of 0.955 g/cm3, a swell ratio of 20, and was produced by the slurry loop method using a Ziegler catalyst.

Example 15
An outer casing material 1 for a storage battery device having the configuration shown in Figure 2 was obtained in the same manner as in Example ⁵ , except that, instead of the high-density polyethylene resin, a low-density polyethylene resin having an MFR of 2 g/10 min at 190°C, a density of 0.921 g/cm3, and a swell ratio of 20 was used as the roughening material contained in the innermost layer film (innermost layer) 7, and which was produced in a gas-phase fluidized bed using a Ziegler catalyst.

<Example 16>
An outer casing material 1 for an electricity storage device having the configuration shown in Figure 2 was obtained in the same manner as in Example ⁵ , except that, instead of the high-density polyethylene resin, a low-density polyethylene resin having an MFR of 3 g/10 min at 190°C, a density of 0.915 g/cm3, and a swell ratio of 35 was used as the roughening material contained in the innermost layer film (innermost layer) 7, and which was produced in a high-pressure autoclave using a peroxide catalyst.

<Example 17>
As the sealant film, a 32 μm-thick first intermediate layer film (first intermediate layer) 8 containing an elastomer-modified olefin resin (block PP) and 500 ppm of erucic acid amide, and an 8 μm-thick innermost layer film (innermost layer) 7 containing an ethylene-propylene random copolymer, 10.0 mass% high-density polyethylene resin (surface-roughening material), and 500 ppm of erucic acid amide were co-extruded using a T-die so as to be laminated in this order in two layers to obtain a 40 μm-thick sealant film (first intermediate layer film 8/innermost layer film 7) 3 obtained by laminating these two layers, and a two-component curing type maleic acid-modified polypropylene adhesive 6 was used. Except for this, an exterior material for an electricity storage device 1 having the configuration shown in FIG. 1 was obtained in the same manner as in Example 1.

<Example 18>
As the sealant film, a 40 μm-thick sealant film (sealant film consisting only of the innermost layer film 7) 3 was used, which was obtained by extruding a composition containing an ethylene-propylene random copolymer, 10.0 mass % of high-density polyethylene resin (surface-roughening material), and 500 ppm of erucic acid amide using a T-die, and this sealant film 3 was laminated on the other side of the dry-laminated aluminum foil 4 via a two-component curing type maleic acid-modified polypropylene adhesive 6. Except for this, an exterior material for a storage battery device 1 having the configuration shown in FIG. 3 was obtained in the same manner as in Example 1.

<Comparative Example 1>
An outer casing material for an electricity storage device was obtained in the same manner as in Example 3, except that the innermost layer film (innermost layer) 7 did not contain a surface-roughening material (high-density polyethylene resin).

<Reference Example 1>
An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that the erucamide content in the second intermediate layer film (second intermediate layer) 9 was changed from 500 ppm to 1000 ppm, the erucamide content in the first intermediate layer film (first intermediate layer) 8 was changed from 500 ppm to 1000 ppm, and the innermost layer film (innermost layer) 7 was a film containing an ethylene-propylene random copolymer, 1000 ppm of erucamide and 2500 ppm of silica particles (anti-blocking agent).

<Reference Example 2>
An outer casing material for an electricity storage device was obtained in the same manner as in Reference Example 1, except that the content of erucamide in the first intermediate layer film (first intermediate layer) 8 was changed from 1000 ppm to 2500 ppm.

<Reference Example 3>
An outer casing material for an electricity storage device was obtained in the same manner as in Reference Example 1, except that the content of erucamide in the first intermediate layer film (first intermediate layer) 8 was changed from 1000 ppm to 5000 ppm.

In addition, in Examples 1 to 18, Comparative Example 1, and Reference Examples 1 to 3, the elastomer-modified olefin-based resin consists of EPR-modified homopolypropylene and EPR-modified ethylene-propylene random copolymer. The EPR stands for ethylene-propylene rubber.

In the table, the following abbreviations represent the following resins.
"Random PP": Ethylene-propylene random copolymer "Block PP": Elastomer-modified olefin resin (polypropylene block copolymer)
"AB agent"...anti-blocking agent "Phillips"...Phillips catalyst "Ziegler"...Ziegler catalyst "Peroxide"...peroxide catalyst "Slurry"...slurry loop method.

The exterior materials for power storage devices obtained as described above were evaluated based on the following evaluation method. The results are shown in Tables 1 to 4. The dynamic friction coefficients of the innermost layer surface shown in Tables 1 to 4 are the dynamic friction coefficients measured for the surface 7a of the innermost layer of each exterior material in accordance with JIS K7125-1995.

<Method for measuring centerline average roughness Ra of the surface of the innermost layer of the exterior material>
In accordance with JIS B0601-2001, the center line average roughness Ra of the surface of the innermost layer of each electrical storage device exterior material was measured using "SURFTEST SV600" manufactured by Mitutoyo Corporation.

<Method for evaluating the amount of lubricant present on the surface of the innermost layer of the exterior material>
Two rectangular test pieces measuring 100 mm long x 100 mm wide were cut out from each of the exterior materials for power storage devices, and the two test pieces were then stacked together and the periphery of each sealant layer was heat-sealed at a heat-sealing temperature of 200°C to produce a bag. 1 mL of acetone was injected into the internal space of the bag using a syringe, and the surface 7a of the innermost layer 7 of the sealant layer was left in contact with the acetone for 3 minutes, after which the acetone was removed from the bag. The amount of lubricant contained in the extracted liquid was measured and analyzed using a gas chromatograph to determine the amount of lubricant (μg/cm ² ) present on the surface of the innermost layer of the exterior material. That is, the amount of lubricant per 1 cm ² of the surface of the innermost layer was determined.

<Method for evaluating the amount of lubricant present on the surface of the outer layer of the packaging material>
The amount of lubricant present on the surface of the outer layer of the packaging material (μg/cm2) was determined in the same manner as in the above "Method for evaluating the amount of lubricant present on the surface of the innermost layer", except that the bag was fabricated so that the outer layer was on the inside of the bag and the surface of the outer layer was brought into contact with acetone. In other words, the amount of lubricant ^per 1 ^cm2 of the surface of the outer layer was determined.

<Moldability evaluation method>
A single-stage deep drawing was performed on the exterior material under the following molding conditions using a straight mold with free molding depth, and the moldability was evaluated for each molding depth (9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm), and the maximum molding depth (mm) at which good molding without any pinholes at the corners could be performed was examined. The maximum molding depth was judged as "◎" when it was 6 mm or more, "○" when it was 4 mm or more and less than 6 mm, and "×" when it was less than 4 mm. The presence or absence of pinholes was examined by visually observing the presence or absence of transmitted light passing through the pinholes.
(Molding conditions)
Mold...Punch: 33.3 mm x 53.9 mm, Die: 80 mm x 120 mm, Corner R: 2 mm, Punch R: 1.3 mm, Die R: 1 mm
Wrinkle holding pressure...gauge pressure: 0.475 MPa, actual pressure (calculated value): 0.7 MPa
Material: SC (carbon steel), punch R only chrome plated.

<Method for assessing the presence or absence of face powder>
A rectangular test piece measuring 600 mm long x 100 mm wide was cut out from each electrical storage device exterior material, and the obtained test piece was placed on a test stand with the inner sealant layer 3 side (i.e., the surface 7a of the innermost layer) facing up, and a SUS weight (mass 1.3 kg, contact surface size 55 mm x 50 mm) with a black cloth wrapped around it and a black surface was placed on the upper surface of the test piece, and the weight was pulled in a horizontal direction parallel to the upper surface of the test piece at a pulling speed of 4 cm/sec, so that the weight was pulled over a length of 400 mm in contact with the upper surface of the test piece. The cloth (black) on the contact surface of the weight after the pulling movement was visually observed, and a case in which noticeable white powder was generated on the surface of the cloth (black) was marked with "x", a case in which only a small amount of white powder was generated was marked with "△", and a case in which there was little or no white powder was recognized was marked with "○". As the black cloth, "Static Electricity Removal Sheet S SD2525 3100" manufactured by TRUSCO Corporation was used.

<Method for evaluating the presence or absence of whitening during molding>
Using a deep drawing tool manufactured by Amada Co., Ltd., the exterior material was deep drawn into a rectangular parallelepiped shape with a depth of 5 mm under the following molding conditions, and the inner surface of the accommodation recess of the obtained molded body (sealant layer side 3) was visually observed, and the presence or absence and the degree of whitening were evaluated based on the following judgment criteria.
(Judgment criteria)
The molded bodies after molding were visually observed, and those with no or almost no whitening were marked with "◎", those with little whitening were marked with "◯", those with some whitening were marked with "△", and those with significant whitening were marked with "X".
(Molding conditions)
Mold...Punch: 33.3 mm x 53.9 mm, Die: 80 mm x 120 mm, Corner R: 2 mm, Punch R: 1.3 mm, Die R: 1 mm
Wrinkle holding pressure...gauge pressure: 0.475 MPa, actual pressure (calculated value): 0.7 MPa
Material: SC (carbon steel), punch R only chrome plated.

As is clear from the table, the exterior materials for electrical storage devices of Examples 1 to 18 of the present invention have excellent moldability, are less likely to produce white powder on the surface of the exterior material, and are also less likely to whiten during molding.

In contrast, Comparative Example 1, which did not contain a surface-roughening material, had poor moldability. Also, to obtain a good evaluation with a configuration that did not contain a surface-roughening material, it was necessary to increase the lubricant content in the sealant layer as in Reference Examples 1 to 3, and to include a large content of antiblocking agent (AB agent) in the innermost layer. If a large amount of antiblocking agent is included in the innermost layer in this way, the antiblocking agent is easily pushed inward when the exterior material is wound up, reducing the slipperiness, and the antiblocking agent is easily dropped off. Also, in Reference Example 3, which had the highest lubricant content in the sealant layer, white powder was clearly visible on the surface of the exterior material.

Specific examples of the electrical storage device packaging material produced using the sealant film according to the present invention and the electrical storage device packaging material according to the present invention include, for example,
Used as an exterior material for various types of electricity storage devices such as lithium secondary batteries (lithium ion batteries, lithium polymer batteries, etc.), lithium ion capacitors, electric double layer capacitors, all-solid-state batteries, etc. Examples of the electricity storage device according to the present invention include the various electricity storage devices exemplified above.

1... Exterior material for electricity storage device 2... Heat-resistant resin layer (outer layer)
3...Sealant layer (inner layer)
4...Metal foil layer 5...Second adhesive layer (outer adhesive layer)
6...First adhesive layer (inner adhesive layer)
7... Innermost layer 7a... Surface of the innermost layer of the sealant layer 8... First intermediate layer 9... Second intermediate layer 10... Outer case for electricity storage device (molded body)
15... Exterior member 30... Electricity storage device 31... Electricity storage device main body

Claims (8)

An exterior material for an electricity storage device, comprising a heat-resistant resin layer as an outer layer, a sealant layer as an inner layer, and a metal foil layer disposed between these layers,
The sealant layer is composed of one or more layers, and the innermost layer of the sealant layer contains a random copolymer containing propylene and other copolymer components excluding propylene as copolymer components, a surface-roughening material, and a lubricant;
The surface roughening material is made of particles containing a thermoplastic resin,
The center line average roughness Ra of the surface of the innermost layer is 0.05 μm to 1 μm,
An exterior material for an electricity storage device, characterized in that the difference between the melt density of the random copolymer containing propylene and other copolymer components other than propylene as copolymer components and the melt density of the surface roughening material is 0.3 g/ ^cm3 or less. The exterior material for a power storage device according to claim 1, wherein the thermoplastic resin constituting the surface-roughening material is a polyethylene resin. The exterior material for a storage battery device according to claim 1 or 2, wherein the content of the surface roughening material in the innermost layer of the sealant layer is 1% by mass to 30% by mass, and the content of the lubricant in the innermost layer is greater than 0 ppm and not more than 1000 ppm. The packaging material for an electricity storage device according to any one of claims 1 to 3 , wherein the sealant layer is made up of a plurality of layers. the sealant layer includes the innermost layer and a first intermediate layer laminated on a surface of the innermost layer facing the metal foil layer,
The first intermediate layer contains an elastomer-modified olefin-based resin,
The elastomer-modified olefin-based resin comprises an elastomer-modified homopolypropylene and/or an elastomer-modified random copolymer,
5 . The exterior material for an electricity storage device according to claim 4 , wherein the elastomer-modified random copolymer is an elastomer-modified product of a random copolymer containing, as copolymerization components, propylene and a copolymerization component other than propylene. the sealant layer includes the innermost layer, a first intermediate layer laminated on a surface of the innermost layer facing the metal foil layer, and a second intermediate layer laminated on a surface of the first intermediate layer facing the metal foil layer,
The first intermediate layer contains an elastomer-modified olefin-based resin,
The elastomer-modified olefin-based resin comprises an elastomer-modified homopolypropylene and/or an elastomer-modified random copolymer,
The elastomer-modified random copolymer is an elastomer-modified random copolymer containing propylene and other copolymer components other than propylene as copolymer components,
The packaging material for an electricity storage device according to claim 4 , wherein the second intermediate layer contains a random copolymer containing, as a copolymerization component, propylene and a copolymerization component other than propylene. An exterior case for an electricity storage device, comprising a molded article of the exterior material for an electricity storage device according to any one of claims 1 to 6 . A power storage device main body;
An exterior member comprising the exterior material for an electricity storage device according to any one of claims 1 to 6 and/or the exterior case for an electricity storage device according to claim 7 ,
The power storage device, wherein the power storage device main body is exteriorly covered with the exterior member.

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