JP2020091990A - Exterior material for power storage device and power storage device - Google Patents

Abstract

To provide an exterior material for a power storage device, good in tape adhesion and excellent in formability.SOLUTION: An exterior material for a power storage device includes a heat-resistant resin layer 2 as an outer layer, a heat-fusible resin layer 3 as an inner layer, and a metal foil layer 4 arranged between both layers. In the exterior material for a power storage device, a slip layer 11 including a fatty acid amide based lubricant is formed on the outer surface of the heat-resistant resin layer 2, and a surfactant is contained in at least a surface region on a slip layer side in the heat-resistant resin layer 2.SELECTED DRAWING: Figure 1

Description

INDUSTRIAL APPLICABILITY The present invention relates to a storage device such as a battery or a capacitor used in a mobile device such as a smartphone or a tablet, a hybrid vehicle, an electric vehicle, wind power generation, solar power generation, a battery or a capacitor used for storing electricity at night. The present invention relates to a packaging material and a power storage device packaged with the packaging material.

In the present specification, the term "wetting tension" means a wetting index (surface tension) measured according to JIS K6768-1999.

In recent years, as mobile electric devices such as smartphones and tablet terminals have become thinner and lighter, the storage devices such as lithium-ion secondary batteries, lithium-polymer secondary batteries, lithium-ion capacitors, and electric double-layer capacitors have been installed in these devices. Instead of the conventional metal can, as the exterior material, a laminate including a heat resistant resin layer/adhesive layer/metal foil layer/adhesive layer/thermoplastic resin layer (inner sealant layer) is used. In addition, power sources for electric vehicles, large-scale power sources for power storage, capacitors, and the like are increasingly being packaged with the above-described laminated body (exterior material). By subjecting the laminate to extrusion molding and deep drawing, a three-dimensional shape such as a substantially rectangular parallelepiped shape is formed. By molding into such a three-dimensional shape, it is possible to secure a housing space for housing the power storage device main body.

In order to form such a three-dimensional shape in a good state without pinholes or breakage, it is required to improve the slipperiness of the surface of the inner sealant layer. As a material for improving the slipperiness of the surface of the inner sealant layer and ensuring good moldability, a structure in which an antiblocking agent (AB agent) is contained in the inner sealant layer is known (see Patent Document 1). ..

Further, it has been proposed to form a lubricant coating layer on the surface of the heat-resistant resin layer to further improve the moldability and perform molding with a deep molding depth (see Patent Document 2).

JP, 2001-266811, A Japanese Patent No. 6222183

By the way, a battery packaged with an exterior material is often housed in a housing together with other electronic circuits, but at this time, the battery exterior material is placed on the outer surface so that the battery does not come into contact with other electronic circuits. Adhesive tape is attached and fixed, but there was a problem that the adhesiveness of the tape could not be sufficiently obtained (the adhesive tape is easily peeled off) due to the presence of a lubricant on the outer surface of the exterior material. . Fatty acid amide lubricants are widely used because they easily move in the inner sealant layer. After preparing the exterior material, the exterior material is wound into a roll so that the heat-resistant resin layer and the inner sealant layer come into contact with each other, and the adhesive is cured by performing heat aging treatment. The fatty acid amide lubricant of the inner sealant layer is easily transferred to the surface of the heat resistant resin layer by the treatment, but at this time, the hydrophobic part of the fatty acid amide lubricant is oriented to the outermost surface side by the heat aging treatment. This reduces the wettability of the surface. As a result, there is a problem that the adhesiveness and printability of the tape are deteriorated (printing is blurred). That is, by using the fatty acid amide lubricant, the transfer becomes sufficient and the moldability can be improved, but the tape adhesion is deteriorated.

The present invention has been made in view of the above technical background, and an object of the present invention is to provide an exterior material for an electricity storage device, which has good tape adhesion and excellent moldability.

In order to achieve the above object, the present invention provides the following means.

[1] An exterior material for an electricity storage device, which includes a heat-resistant resin layer as an outer layer, a heat-fusible resin layer as an inner layer, and a metal foil layer arranged between these layers,
A slip layer containing a fatty acid amide-based lubricant is formed on the outer surface of the heat-resistant resin layer, and a surface material at least on the slip layer side of the heat-resistant resin layer contains a surfactant. ..

[2] The exterior material for an electricity storage device according to the above item 1, wherein the surfactant content in the surfactant-containing region of the heat resistant resin layer is 500 ppm to 30,000 ppm.

[3] An exterior material for an electricity storage device, which includes a heat-resistant resin layer as an outer layer, a heat-fusible resin layer as an inner layer, and a metal foil layer arranged between these layers,
A protective resin layer is formed on the outer surface of the heat-resistant resin layer, a slip layer containing a fatty acid amide lubricant is formed on the outer surface of the protective resin layer, and a surfactant is present in at least the slip layer side surface region of the protective resin layer. An outer casing material for an electricity storage device, which comprises:

[4] The exterior material for an electricity storage device according to the above item 3, wherein the surfactant content in the surfactant-containing region of the protective resin layer is 500 ppm to 30,000 ppm.

[5] exterior material for a power storage device according to any one of the preceding 1-4 the content of the fatty acid amide lubricant is 0.10μg / cm ² ~1.0μg / cm ² in the slip layer.

[6] The exterior material for an electricity storage device according to any one of the above items 1 to 5, wherein the heat-fusible resin layer is formed of a polyolefin resin containing a fatty acid amide lubricant and an anti-blocking agent.

[7] A power storage device body,
The exterior material according to any one of the above items 1 to 6,
An electricity storage device, wherein the electricity storage device body is covered with the exterior material.

In the invention [1], since the slip layer containing the fatty acid amide lubricant is formed on the outer surface, the moldability is excellent. Further, since the surfactant-containing layer (heat resistant resin layer) is present in contact with the slip layer, the wettability is good and the tape adhesion is good. This is because at least part of the hydrophilic groups of the lubricant is likely to be on the surface side because the orientation (the hydrophobic groups are aligned on the surface side) occurring in the fatty acid amide lubricant when heated by heat aging is inhibited by the surfactant. It is presumed that it can be exposed and the wettability is improved even in the presence of the fatty acid amide lubricant (estimation is not certain).

In the invention [2], since the surfactant content is 500 ppm to 30,000 ppm, the wettability of the surface can be further improved, the tape adhesion can be further improved, and the transparency and mechanical properties of the heat resistant resin layer can be improved. There is no loss.

In the invention [3], since the slip layer containing the fatty acid amide lubricant is formed on the outer surface, the moldability is excellent. Further, since the surfactant-containing layer (protective resin layer) is present in contact with the slip layer, the wettability is good and the tape adhesion is good. This is because at least part of the hydrophilic groups of the lubricant is likely to be on the surface side because the orientation (the hydrophobic groups are aligned on the surface side) occurring in the fatty acid amide lubricant when heated by heat aging is inhibited by the surfactant. It is presumed that it can be exposed and the wettability is improved even in the presence of the fatty acid amide lubricant (estimation is not certain).

In the invention [4], since the surfactant content is 500 ppm to 30,000 ppm, the wettability of the surface can be further improved, the tape adhesion can be further improved, and the transparency of the heat resistant resin layer is not impaired. ..

In the invention [5], when it is 0.10 μg/cm ² or more, the moldability can be further improved, and when it is 1.0 μg/cm ² or less, the tape adhesion and the transparency are deteriorated due to the generation of white powder. Can be suppressed.

In the invention [6], since the heat-fusible resin layer is formed of a polyolefin resin containing a fatty acid amide lubricant and an anti-blocking agent, the exterior material is rolled and stored in continuous production. However, since the slip layer and the heat-fusible resin layer are stored in close contact with each other at this time, transfer transfer from the heat-fusible resin layer to the slip layer of the fatty acid amide lubricant is performed, It becomes easy to adjust the amount of lubricant in the slip layer.

According to the invention [7], it is possible to provide an electricity storage device in which the exterior material has good tape adhesion.

It is sectional drawing which shows one Embodiment of the exterior material for electric storage devices which concerns on this invention. It is sectional drawing which shows other embodiment of the exterior material for electrical storage devices which concerns on this invention. It is sectional drawing which shows one Embodiment of the electrical storage device which concerns on this invention. FIG. 4 is a perspective view showing an exterior material (planar), an electricity storage device main body, and an exterior case (molded body formed in a three-dimensional shape) that constitute the electricity storage device of FIG. 3 in a separated state before heat sealing.

FIG. 1 shows one embodiment of the exterior material 1 for an electricity storage device according to the present invention. This electricity storage device exterior material 1 is configured to include a heat-resistant resin layer 2 as an outer layer, a heat-fusible resin layer 3 as an inner layer, and a metal foil layer 4 arranged between these layers. In addition, the slip layer 11 containing a fatty acid amide lubricant is formed on the outer surface of the heat resistant resin layer 2, and a surfactant is contained in at least the surface area of the heat resistant resin layer on the slip layer side. Since the slip layer 11 containing a fatty acid amide lubricant is formed on the outer surface of the exterior material 1 for an electricity storage device, it is excellent in moldability. Further, since the surfactant-containing layer (heat-resistant resin layer) is present in contact with the slip layer 11, the wettability is good and the tape adhesion is good. The reason for this is that the orientation that occurs in the fatty acid amide lubricant when it is heated by heat aging (the hydrophobic groups are aligned on the surface side) is inhibited by the surfactant, so at least part of the hydrophilic groups of the lubricant is probably on the surface side. It is presumed that the wettability will be improved even if the fatty acid amide lubricant is present (presumed but not certain).

Another embodiment of the exterior material 1 for an electricity storage device according to the present invention is shown in FIG. This electricity storage device exterior material 1 is configured to include a heat-resistant resin layer 2 as an outer layer, a heat-fusible resin layer 3 as an inner layer, and a metal foil layer 4 arranged between these layers. The protective resin layer 12 is formed on the outer surface of the heat resistant resin layer 2, the slip layer 11 containing a fatty acid amide lubricant is formed on the outer surface of the protective resin layer 12, and at least the slip layer of the protective resin layer 12 is formed. The surface area on the side contains a surfactant. Since the slip layer 11 containing a fatty acid amide lubricant is formed on the outer surface of the exterior material 1 for an electricity storage device, it is excellent in moldability. Further, since the surfactant-containing layer (protective resin layer 12) is in contact with the slip layer 11, the wettability is good and the tape adhesion is good.

In the above embodiment shown in FIGS. 1 and 2, the exterior material 1 has a heat-resistant resin layer on one surface (upper surface) of the metal foil layer 4 with an outer adhesive layer (first adhesive layer) 5 interposed therebetween. The (outer layer) 2 is laminated and integrated, and a heat-fusible resin layer (inner layer) is formed on the other surface (lower surface) of the metal foil layer 4 via an inner adhesive layer (second adhesive layer) 6. ) 3 are laminated and integrated.

The fatty acid amide lubricant is not particularly limited, and examples thereof include saturated fatty acid amide and unsaturated fatty acid amide. Examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. The unsaturated fatty acid amide is not particularly limited, and examples thereof include oleic acid amide and erucic acid amide. It is preferable to incorporate such a fatty acid amide lubricant in the heat-fusible resin layer 3. After producing the exterior material, the exterior is formed into a roll so that the heat-resistant resin layer 2 and the heat-fusible resin layer 3 come into contact with each other or the protective resin layer 12 and the heat-fusible resin layer 3 come into contact with each other. The adhesive is cured by winding the material and performing an aging treatment at a predetermined temperature in the wound state. The fatty acid amide-based lubricant of the heat-fusible resin layer 3 is formed by the aging treatment as described above. It is transferred to the surface of the heat resistant resin layer 2 or the surface of the protective resin layer 12 to form the slip layer 11 containing a fatty acid amide lubricant (see FIGS. 1 and 2). The content of the fatty acid amide lubricant in the heat-fusible resin layer 3 is preferably set in the range of 500 ppm to 7000 ppm.

In the present invention, the amount of the surfactant added is preferably set in the range of 500 ppm to 30,000 ppm, more preferably set in the range of 1000 ppm to 20,000 ppm. That is, when a surfactant is contained in the outer layer 2, the content ratio of the surfactant in the surfactant-containing region of the outer layer (heat resistant resin layer) is preferably 500 ppm to 30,000 ppm. When the protective resin layer 12 contains a surfactant, the content of the surfactant in the surfactant-containing region of the protective resin layer 12 is preferably 500 ppm to 30,000 ppm. When the protective resin layer 12 is composed of a single layer, the expression “surfactant-containing region” means the entire protective resin layer (region), and the protective resin layer is composed of two layers. When the surfactant is added only to the slip layer side layer, it means the slip layer side layer (region) in the protective resin layer (two-layer lamination).

As the surfactant, it is preferable to use a surfactant having a hydrophilic group. For example, as the anionic surfactant, it is preferable to use a surfactant having a sulfo group, a sulfuric acid ester group, a phosphoric acid ester group or a phosphonic acid group. As the cationic surfactant, it is preferable to use a surfactant having a quaternary ammonium salt, a pyridinium group or a polyethylene polyamine group. As the nonionic surfactant, it is preferable to use a surfactant having an amino alcohol group, a glycerin group, a sorbitol group, a polyhydric alcohol group or a polyethylene glycol group. As the amphoteric surfactant, it is preferable to use a surfactant having an amino acid group, a betaine group, a sulfobetaine group or an aminosulfate group.

In the present invention, the outer layer 2 is formed of a heat resistant resin layer. As the heat-resistant resin forming the heat-resistant resin layer 2, a heat-resistant resin that does not melt at the heat-sealing temperature when heat-sealing the exterior material 1 is used. As the heat-resistant resin, it is preferable to use a heat-resistant resin having a melting point higher than the melting point of the heat-fusible resin forming the heat-fusible resin layer 3 by 10° C. or more, and 20 times higher than the melting point of the heat-fusible resin. It is particularly preferable to use a heat resistant resin having a melting point higher than 0°C.

The heat-resistant resin layer (outer layer) 2 is a member mainly responsible for ensuring good moldability, that is, mainly for preventing breakage due to necking of the aluminum foil during molding.

The heat-resistant resin layer (outer layer) 2 is not particularly limited, but examples thereof include a stretched polyamide film such as a stretched nylon film and a stretched polyester film. Among them, as the heat-resistant resin layer 2, biaxially stretched polyamide film such as biaxially stretched nylon film, biaxially stretched polybutylene terephthalate (PBT) film, biaxially stretched polyethylene terephthalate (PET) film, biaxially stretched polyethylene It is preferable to use a phthalate (PEN) film or a biaxially oriented polypropylene film. As the heat resistant resin layer 2, it is preferable to use a heat resistant resin biaxially stretched film stretched by a simultaneous biaxial stretching method. The nylon is not particularly limited, and examples thereof include 6 nylon, 6,6 nylon, MXD nylon, 610 nylon (PA610), 11 nylon (PA11), and 12 nylon (PA12). The heat-resistant resin film layer 2 may be formed of a single layer (single stretched film), or may be a multi-layer (stretched PET film/stretched nylon film) made of, for example, stretched polyester film/stretched polyamide film. It may be formed of a multilayer including a film).

The heat resistant resin layer 2 preferably has a thickness of 10 μm to 50 μm. Sufficient strength as an exterior material can be ensured by setting the above preferable lower limit value or more, and by setting the above preferable upper limit value or less, stress at the time of overhang molding or draw forming can be reduced and moldability can be improved. You can

When the protective resin layer 12 is provided, the protective resin layer 12, which is the outermost layer, contains a surfactant. The protective resin layer 12 is, for example, an aqueous emulsion (aqueous emulsion) of one or more resins selected from the group consisting of epoxy resin, urethane resin, acrylic ester resin, methacrylic ester resin and polyethyleneimine resin. It can be formed by applying a coating solution in which a surfactant is added to the coating solution by a spray coating method, a gravure roll coating method, a reverse roll coating method, a lip coating method, or the like and drying the coating solution. Alternatively, it may be formed by applying a coating liquid containing a base resin containing a urethane resin, a curing agent containing a polyisocyanate, and a surfactant, and drying the coating liquid. The thickness of the protective resin layer 12 is preferably set to 2 μm to 5 μm. Examples of the resin forming the protective resin layer 12 include polyester resins, polyolefin resins, fluororesins, phenoxy resins, and the like, in addition to the above resins.

Fine particles having an average particle diameter of 1 μm to 10 μm may be added to the protective resin layer 12. Examples of the fine particles include inorganic fine particles such as silica, kaolin, and barium sulfate, and organic fine particles such as silicone resin beads, acrylic resin beads, and fluororesin beads. In addition, silicone resin, polyethylene wax, and fluorine-containing polyethylene wax may be added. Further, a lubricant may be added.

As described above, the slip layer 11 is formed by transferring the fatty acid amide lubricant of the heat-fusible resin layer 3 onto the surface of the heat resistant resin layer 2 or the surface of the protective resin layer 12. Is preferred. Alternatively, the slip layer 11 containing the fatty acid amide-based lubricant may be formed by directly coating the surface of the heat resistant resin layer 2 or the surface of the protective resin layer 12. The amount of fatty acid amide-based lubricant in the slip layer 11 is preferably a ^{0.10μg / cm 2 ~1.0μg / cm 2} .

In the present invention, the metal foil layer 4 plays a role of imparting a gas barrier property to the exterior material 1 to prevent invasion of oxygen and moisture. The metal foil layer 4 is not particularly limited, but examples thereof include aluminum foil, SUS foil, Cu foil, Ni foil, Ti foil, and the like, and aluminum foil is generally used. The metal foil layer 4 preferably has a thickness of 5 μm to 50 μm. When it is 5 μm or more, pinholes can be prevented from being generated during rolling when manufacturing a metal foil, and when it is 50 μm or less, stress at the time of forming such as overhang forming and draw forming can be reduced to improve formability. be able to.

It is preferable that at least the inner surface (the surface on the side of the heat-fusible resin layer 3) of the metal foil layer 4 is subjected to a chemical conversion treatment. By performing such a chemical conversion treatment, it is possible to sufficiently prevent the corrosion of the surface of the metal foil by the contents (such as the electrolytic solution of the battery). For example, the metal foil is subjected to a chemical conversion treatment by the following treatment. That is, for example, on the surface of the metal foil subjected to degreasing treatment,
1) phosphoric acid,
Chromic acid,
An aqueous solution of a mixture containing at least one compound selected from the group consisting of metal salts of fluorides and non-metal salts of fluorides 2) phosphoric acid;
At least one resin selected from the group consisting of acrylic resins, chitosan derivative resins and phenolic resins;
An aqueous solution of a mixture containing at least one compound selected from the group consisting of chromic acid and chromium (III) salts, 3) phosphoric acid, and
At least one resin selected from the group consisting of acrylic resins, chitosan derivative resins and phenolic resins;
At least one compound selected from the group consisting of chromic acid and a chromium (III) salt;
Aqueous solution of mixture containing at least one compound selected from the group consisting of metal salts of fluoride and non-metal salt of fluoride, and applied with an aqueous solution of any one of the above 1) to 3) and then dried. By doing so, chemical conversion treatment is performed.

The conversion coating, chromium coating weight preferably is 0.1mg / m ² ~50mg / m ² as a (per one surface), in particular 2mg / m ² ~20mg / m 2 preferred.

The heat-fusible resin layer (inner layer) 3 has excellent chemical resistance against a highly corrosive electrolytic solution used in a lithium ion secondary battery or the like, and has a heat-sealing property as an exterior material. Is responsible for giving.

The resin constituting the heat-fusible resin layer 3 is not particularly limited, but examples thereof include polyethylene, polypropylene, ionomer, ethylene ethyl acrylate (EEA), ethylene methyl acrylate (EMA), ethylene methacryl Examples thereof include acid methyl resin (EMMA), ethylene-vinyl acetate copolymer resin (EVA), maleic anhydride modified polypropylene, maleic anhydride modified polyethylene and the like.

The thickness of the heat-fusible resin layer 3 is preferably set to 10 μm to 100 μm. When the thickness is 10 μm or more, sufficient heat sealing strength can be secured, and when the thickness is 100 μm or less, it contributes to thinning and weight reduction. Above all, the thickness of the heat-fusible resin layer 3 is more preferably set to 10 μm to 80 μm. The heat-fusible resin layer 3 is preferably formed of a heat-fusible resin unstretched film layer, and the heat-fusible resin layer 3 may be a single layer or a multi-layer. It may be.

The thickness of the outer adhesive layer 5 is preferably 1 μm to 5 μm. The outer adhesive is not particularly limited, but examples thereof include a two-component curing type urethane adhesive.

The thickness of the inner adhesive layer 6 is preferably 1 μm to 5 μm. The inner adhesive is not particularly limited, and examples thereof include an olefin adhesive, an epoxy adhesive, an acrylic adhesive, and a thermosetting adhesive.

An outer case (battery case or the like) 14 can be obtained by molding (deep-drawing, bulging, etc.) the outer casing 1 for an electricity storage device of the present invention (see FIGS. 3 and 4). The exterior material 1 of the present invention can be used as it is without being subjected to molding (see FIGS. 3 and 4).

FIG. 3 shows an embodiment of an electricity storage device 30 configured by using the electricity storage device exterior material 1 of FIG. 1. The electricity storage device 30 is a lithium-ion secondary battery. In this embodiment, as shown in FIGS. 3 and 4, the exterior case 14 obtained by molding the exterior material 1 and the planar exterior material 1 constitute an exterior member 15. Then, a substantially rectangular parallelepiped electricity storage device main body (electrochemical element or the like) 31 is accommodated in the accommodation recess of the exterior case 14 obtained by molding the exterior material 1 of the present invention. The heat-fusible resin layer of the planar outer packaging material 1 is arranged on the top of the flat outer packaging material 1 with the heat-fusible resin layer 3 side thereof facing inward (lower side) without being molded. 3 and the heat-fusible resin layer 3 of the flange portion (sealing peripheral portion) 29 of the outer case 14 are sealed and joined by heat sealing, whereby the electricity storage device of the present invention 30 is configured (see FIGS. 3 and 4). The surface inside the housing recess of the outer case 14 is a heat-fusible resin layer 3, and the outer surface of the housing recess is a base material layer (outer layer) 2 (see FIG. 4).

In FIG. 3, reference numeral 39 denotes a heat seal portion in which the peripheral edge portion of the exterior material 1 and the flange portion (sealing peripheral edge portion) 29 of the exterior case 14 are joined (welded). In the electricity storage device 30, the tip ends of the tab leads connected to the electricity storage device body 31 are led out of the exterior member 15, but are not shown.

The electricity storage device body 31 is not particularly limited, but examples thereof include a battery body, a capacitor body, a capacitor body, and the like.

In the above-described embodiment, the exterior member 15 has a configuration including the exterior case 10 obtained by molding the exterior material 1 and the planar exterior material 1 (see FIGS. 3 and 4). The combination is not particularly limited to such a combination, and for example, the exterior member 15 may be configured by a pair of planar exterior materials 1 or may be configured by a pair of exterior cases 14. May be.

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

<Example 1>
A polyethylene glycol nonionic surfactant having an average molecular weight of 3000 was added to the 6 nylon pellets so that the concentration was 15000 ppm, and then a biaxially stretched nylon film (outer layer) 2 having a thickness of 25 μm was prepared by a tubular method.

A chemical conversion treatment liquid consisting of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water and alcohol is applied to both surfaces of the 40 μm thick aluminum foil 4 and then dried at 180° C. , A chemical conversion film was formed. The amount of chromium deposited on this chemical conversion film was 10 mg/m ² per side.

Next, the biaxially stretched nylon film (outer layer) 2 was dry-laminated on one surface of the chemical conversion treated aluminum foil 4 via a two-component curing type urethane adhesive (thickness 2 μm) 5 ( Pasted together).

Next, a 6 μm-thick first unstretched film containing an ethylene-propylene random copolymer and 1000 ppm erucic acid amide, a thickness containing an ethylene-propylene block copolymer and 1000 ppm erucic acid amide. The second die-unstretched film having a thickness of 28 μm, the ethylene-propylene random copolymer, and the third unstretched film having a thickness of 6 μm and containing 1000 ppm of erucic acid amide were laminated in this order in three layers to form a T-die. After obtaining a sealant film (inner layer) 3 having a thickness of 40 μm by coextrusion using the sealant film 3, the first unstretched film surface of the sealant film 3 is treated with a two-component curing type maleic acid-modified polypropylene adhesive (thickness). 3 μm) on the other surface of the aluminum foil 4 after the dry lamination, and sandwiched between a rubber nip roll and a laminating roll heated to 100° C. and pressure-bonded for dry lamination. After that, the exterior material is wound into a roll in a mode in which the biaxially stretched nylon film 2 and the third non-stretched film are in contact with each other, and in this wound state, the sealant film is aged (heated) at 40° C. for 10 days. A lubricant (erucic acid amide) was transferred from the (inner layer) to the surface of the nylon film 2 to form the slip layer 11, thereby obtaining the exterior material 1 for an electricity storage device having the configuration shown in FIG. 1. The amount of lubricant in the slip layer 11 was 0.20 μg/cm ² .

<Example 2>
A biaxially stretched nylon film (outer layer) with a thickness of 25 μm prepared by adding a polyethylene glycol-based nonionic surfactant having an average molecular weight of 3000 to an aqueous emulsion of urethane resin to a concentration of 10000 ppm with respect to the amount of urethane resin 2 The protective resin layer 12 was formed by applying it on one surface and drying it (formation amount: 0.1 g/m ² ).

A chemical conversion treatment liquid consisting of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water and alcohol is applied to both surfaces of the 40 μm thick aluminum foil 4 and then dried at 180° C. , A chemical conversion film was formed. The amount of chromium deposited on this chemical conversion film was 10 mg/m ² per side.

Next, the other surface of the biaxially stretched nylon film (outer layer) 2 is attached to one surface of the chemical conversion treated aluminum foil 4 via a two-component curing type urethane adhesive (thickness 2 μm) 5. Dry laminated (pasted).

Next, a 6 μm-thick first unstretched film containing an ethylene-propylene random copolymer and 1000 ppm erucic acid amide, a thickness containing an ethylene-propylene block copolymer and 1000 ppm erucic acid amide. The second die-unstretched film having a thickness of 28 μm, the ethylene-propylene random copolymer, and the third unstretched film having a thickness of 6 μm and containing 1000 ppm of erucic acid amide were laminated in this order in three layers to form a T-die. After obtaining a sealant film (inner layer) 3 having a thickness of 40 μm by coextrusion using the sealant film 3, the first unstretched film surface of the sealant film 3 is treated with a two-component curing type maleic acid-modified polypropylene adhesive (thickness). 3 μm) on the other surface of the aluminum foil 4 after the dry lamination, and sandwiched between a rubber nip roll and a laminating roll heated to 100° C. and pressure-bonded for dry lamination. After that, the exterior material is wound into a roll in a mode in which the biaxially stretched nylon film 2 and the third non-stretched film are in contact with each other, and in this wound state, the sealant film is aged (heated) at 40° C. for 10 days. A lubricant (erucic acid amide) was transferred from the (inner layer) to the surface of the protective resin layer 12 to form the slip layer 11, and thus the exterior material 1 for an electricity storage device having the configuration shown in FIG. 2 was obtained. The amount of lubricant in the slip layer 11 was 0.50 μg/cm ² .

<Example 3>
For the electricity storage device having the configuration shown in FIG. 2, in which the slip layer 11 is formed on the surface of the protective resin layer 12 in the same manner as in Example 2 except that the protective resin layer 12 is formed as follows. Exterior material 1 was obtained. The slip layer 11 formed by transfer had a lubricant amount of 0.40 μg/cm ² . That is, on one surface of a biaxially stretched nylon film (outer layer) 2 having a thickness of 25 μm, a main agent containing a urethane resin, a curing agent containing an aromatic diisocyanate and an aliphatic diisocyanate, and silica particles having an average particle size of 2 μm A coating solution obtained by mixing 10,000 ppm of a polyethylene glycol-based nonionic surfactant having an average molecular weight of 3000 was applied using a gravure roll and then dried to form a protective resin layer 12 having a dry thickness of 3 μm.

<Example 4>
The electricity storage having the configuration shown in FIG. 2 in which the slip layer 11 is formed on the surface of the protective resin layer 12 in the same manner as in Example 2 except that the lubricant content in the sealant film (inner layer) 3 is changed to 2500 ppm. A device exterior material 1 was obtained. The slip layer 11 formed by transfer had a lubricant amount of 0.80 μg/cm ² .

<Example 5>
The electricity storage having the structure shown in FIG. 2 in which the slip layer 11 is formed on the surface of the protective resin layer 12 in the same manner as in Example 2 except that the lubricant content in the sealant film (inner layer) 3 is changed to 4000 ppm. A device exterior material 1 was obtained. The amount of lubricant in the slip layer 11 formed by transfer was 1.20 μg/cm ² .

<Example 6>
From the sealant film (inner layer) to the lubricant (erucic acid amide), in the same manner as in Example 1 except that the content of the polyethylene glycol nonionic surfactant in the biaxially stretched nylon film (outer layer) 2 was set to 30,000 ppm. Was transferred to the surface of the nylon film 2 to form the slip layer 11 to obtain the exterior material 1 for an electricity storage device having the configuration shown in FIG. The amount of lubricant in the slip layer 11 was 0.50 μg/cm ² .

<Example 7>
From the sealant film (inner layer) to the lubricant (erucic acid amide), in the same manner as in Example 1 except that the content of the polyethylene glycol-based nonionic surfactant in the biaxially stretched nylon film (outer layer) 2 was set to 40,000 ppm. Was transferred to the surface of the nylon film 2 to form the slip layer 11 to obtain the exterior material 1 for an electricity storage device having the configuration shown in FIG. The amount of lubricant in the slip layer 11 was 0.50 μg/cm ² .

<Example 8>
The slip layer 11 is formed on the surface of the protective resin layer 12 in the same manner as in Example 2 except that the content of the polyethylene glycol-based nonionic surfactant in the protective resin layer 12 is set to 1000 ppm. The exterior material 1 for an electricity storage device having the configuration shown was obtained. The slip layer 11 formed by transfer had a lubricant amount of 0.50 μg/cm ² .

<Example 9>
The slip layer 11 is formed on the surface of the protective resin layer 12 in the same manner as in Example 2 except that the content of the polyethylene glycol-based nonionic surfactant in the protective resin layer 12 is set to 200 ppm. The exterior material 1 for an electricity storage device having the configuration shown was obtained. The slip layer 11 formed by transfer had a lubricant amount of 0.50 μg/cm ² .

<Example 10>
The slip layer 11 is formed on the surface of the protective resin layer 12 in the same manner as in Example 2 except that sodium alkylbenzene sulfonate (anionic surfactant) is used instead of the polyethylene glycol-based nonionic surfactant. Then, the exterior material 1 for an electricity storage device having the configuration shown in FIG. 2 was obtained. The slip layer 11 formed by transfer had a lubricant amount of 0.50 μg/cm ² .

<Example 11>
The slip layer 11 was formed on the surface of the protective resin layer 12 in the same manner as in Example 2 except that distearyldimethylammonium chloride (cationic surfactant) was used in place of the polyethylene glycol-based nonionic surfactant. Thus, the exterior material 1 for an electricity storage device having the configuration shown in FIG. 2 was obtained. The slip layer 11 formed by transfer had a lubricant amount of 0.50 μg/cm ² .

<Comparative Example 1>
The obtained exterior material is cut into a rectangular shape without winding the exterior material in a roll shape, and then the biaxially stretched nylon film and the third non-stretched film are placed between them so as not to come into contact with each other. An outer casing material for an electricity storage device was obtained in the same manner as in Example 1 except that aging was carried out in this state at 40° C. for 10 days. The slip layer 11 was not formed on the surface of the nylon film (outer layer) 2.

<Comparative example 2>
The obtained exterior material is cut into a rectangular shape without winding the exterior material in a roll shape, and then paper is sandwiched between them so that the protective resin layer and the third non-stretched film do not come into contact with each other. Then, an outer casing material for an electricity storage device was obtained in the same manner as in Example 2 except that aging was performed at 40° C. for 10 days in this state. The slip layer 11 was not formed on the surface of the protective resin layer 12.

<Comparative example 3>
The obtained exterior material is cut into a rectangular shape without winding the exterior material in a roll shape, and then paper is sandwiched between them so that the protective resin layer and the third non-stretched film do not come into contact with each other. Then, an outer casing material for an electricity storage device was obtained in the same manner as in Example 3 except that aging was performed at 40° C. for 10 days in this state. The slip layer 11 was not formed on the surface of the protective resin layer 12.

<Comparative example 4>
An outer casing material for an electricity storage device, in which the slip layer 11 is formed on the surface of the protective resin layer 12 is performed in the same manner as in Example 2 except that the protective resin layer does not contain a polyethylene glycol nonionic surfactant. Obtained.

<Comparative Example 5>
An outer casing material for an electricity storage device was obtained in the same manner as in Example 2 except that the lubricant content in the sealant film (inner layer) 3 was changed to 0 ppm (no lubricant was added). The slip layer 11 was not formed on the surface of the protective resin layer 12.

With respect to the exterior material for an electricity storage device obtained as described above, the amount of lubricant in the slip layer was evaluated, while the formability, wettability and tape adhesion of the exterior material were evaluated.

<Evaluation method of the amount of lubricant in the slip layer>
After cutting two rectangular test pieces of 100 mm in length×100 mm in width from each outer packaging material for electric storage devices, these two test pieces were stacked so that the outer layer (the side with the slip layer) was on the inner side. The peripheral portions of each other were heat-sealed at a heat-sealing temperature of 250° C. with a sealing width of 5 mm to produce a bag. Acetone (1 mL) was injected into the inner space of the bag using a syringe, and left for 3 minutes while the inner surface of the bag was in contact with acetone, and then the acetone in the bag was removed. The amount of the lubricant contained in the slip layer 11 (μg/cm ² ) was determined by measuring and analyzing the amount of the components contained in the extracted liquid using a gas chromatograph.

<Moldability evaluation method>
The exterior material 1 was molded by a press molding machine to a length of 150 mm × a width of 150 mm × a depth of 5 mm to obtain a molded product, and the molded product was visually inspected to find no cracks or pinholes. Those that were cracked or pinholes were marked as "X".

<Wettability evaluation method>
The wetting index (surface tension) of the surface of the outer layer of the outer case for each electricity storage device was determined using a wettability reagent according to JIS K6768-1999, and evaluated based on the following criteria.
(Criteria)
"A"... Wetting tension is 35 mN/m or more "O"... Wetting tension is 30 mN/m or more and less than 35 mN/m "X"... Wetting tension is less than 30 mN/m.

<Tape adhesion evaluation method>
A rectangular test piece having a length of 150 mm and a width of 200 mm was sampled from the exterior material for the electricity storage device. After sticking a double-sided adhesive tape having a width of 5 mm and a length of 100 mm on the surface (outer surface) of the slip layer 11 in the test piece, the exterior material and the adhesive tape were integrally cut into a size of a width of 5 mm and a length of 150 mm. This was attached to an acrylic plate having a thickness of 1.5 mm. Next, while the acrylic plate was placed horizontally on the horizontal table with the exterior material side facing up, while applying a load to the exterior material with a roller weighing 2 kg, the roller was reciprocated 5 times on the exterior material to adhere. The tape was applied sufficiently. Then, it was left to stand in a room at 25° C. for 1 hour. Next, in accordance with JIS K6854-2 (1999), the test piece (exterior material) was sandwiched and fixed with one chuck using a Shimadzu Strograph AGS-5kNX, and the other chuck was used to hold an acrylic plate. The adhesive tape (including the adhesive tape) was sandwiched and fixed, and the 180° peel strength between the exterior material and the adhesive tape was measured. The tape adhesion was evaluated from the peel strength based on the following criteria.
(Criteria)
"A" (pass)... Peel strength is 6N/5mm or more "O" (pass)... Peel strength is 5N/5mm or more, less than 6N/5mm "X"... Peel strength is less than 5N/5mm ..

As is apparent from the table, the exterior materials of Examples 1 to 11 of the present invention had good moldability and good tape adhesion.

On the other hand, in Comparative Examples 1 to 5, which deviate from the specified range of the present invention, at least one or more of “moldability”, “wettability”, and “tape adhesion” was poor.

The exterior material for an electricity storage device according to the present invention is, for example, as a specific example,
-Used as an outer packaging material for various power storage devices such as lithium secondary batteries (lithium ion batteries, lithium polymer batteries, etc.), lithium ion capacitors, electric double layer capacitors, etc. Further, the power storage device according to the present invention includes all-solid-state batteries in addition to the power storage device exemplified above.

1... Exterior material for electricity storage device 2... Heat-resistant resin layer (outer layer)
3... Heat-fusible resin layer (inner layer)
4... Metal foil layer 11... Slip layer 12... Protective resin layer 30... Electric storage device 31... Electric storage device main body

Claims (7)

A heat-resistant resin layer as an outer layer, a heat-fusible resin layer as an inner layer, and a metal foil layer arranged between these two layers, which is an exterior material for an electricity storage device,
A slip layer containing a fatty acid amide-based lubricant is formed on the outer surface of the heat-resistant resin layer, and a surface material at least on the slip layer side of the heat-resistant resin layer contains a surfactant. .. The exterior material for an electricity storage device according to claim 1, wherein the content rate of the surfactant in the surfactant-containing region of the heat resistant resin layer is 500 ppm to 30,000 ppm. A heat-resistant resin layer as an outer layer, a heat-fusible resin layer as an inner layer, and a metal foil layer arranged between these two layers, which is an exterior material for an electricity storage device,
A protective resin layer is formed on the outer surface of the heat-resistant resin layer, a slip layer containing a fatty acid amide lubricant is formed on the outer surface of the protective resin layer, and a surfactant is present in at least the slip layer side surface region of the protective resin layer. An outer casing material for an electricity storage device, which comprises: The outer packaging material for an electricity storage device according to claim 3, wherein the surfactant content in the surfactant-containing region of the protective resin layer is 500 ppm to 30,000 ppm. Exterior material for a power storage device according to any one of claims 1 to 4 the content of the fatty acid amide lubricant is 0.10μg / cm ² ~1.0μg / cm ² in the slip layer. The exterior material for an electricity storage device according to any one of claims 1 to 5, wherein the heat-fusible resin layer is formed of a polyolefin resin containing a fatty acid amide lubricant and an antiblocking agent. An electricity storage device body,
An exterior material according to any one of claims 1 to 6, comprising:
An electricity storage device, wherein the electricity storage device body is covered with the exterior material.

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