JP2020098707A - Exterior material for power storage device and power storage device - Google Patents

Abstract

To provide an exterior material for a power storage device, having an excellent formability as well as having an excellent tape adhesion performance.SOLUTION: An exterior material for a power storage device includes: a heat-resistant resin layer 2 as an outside layer; a thermal fusion resin layer 3 as an inside layer; and a metal foil layer 4 arranged between these two layers. The thermal fusion resin layer 3 contains a fatty acid amide type slip agent and a surface active agent. The exterior material for the power storage device is structured so that a slip layer 11 containing the fatty acid amide type slip agent and the surface active agent is formed on an outside face of the heat-resistant resin layer.SELECTED DRAWING: Figure 1

Description

INDUSTRIAL APPLICABILITY The present invention relates to a storage device such as a battery or a capacitor used for 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 addition, in this specification, the term "wetting tension" means the 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 laminate (exterior material) having the above configuration. By subjecting the laminate to extrusion molding and deep drawing molding, 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 to ensure good moldability, a structure in which the inner sealant layer contains an anti-blocking agent (AB agent) is known (see Patent Document 1). ..

Further, it has been proposed to form a coating layer of a lubricant 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 a packaging material is often housed in a housing together with other electronic circuits.At this time, the battery packaging material is placed on the outer surface of the battery packaging material 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 are in contact with each other, and the adhesive is cured by performing heat aging treatment. The fatty acid amide-based 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-based lubricant is oriented to the outermost surface side by the heat aging treatment, so that the surface Wettability decreases. As a result, there is a problem in 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 lowered.

The present invention has been made in view of such 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] A packaging 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 the both layers,
The heat-fusible resin layer contains a fatty acid amide lubricant and a surfactant,
An exterior material for an electricity storage device, wherein a slip layer containing a fatty acid amide lubricant and a surfactant is formed on the outer surface of the heat resistant resin layer.

[2] 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,
The heat-fusible resin layer contains a fatty acid amide lubricant and a surfactant,
A protective material layer is formed on the outer surface of the heat resistant resin layer, and a slip layer containing a fatty acid amide lubricant and a surfactant is formed on the outer surface of the protective resin layer.

[3] exterior material for a power storage device according the content of the fatty acid amide-based lubricant in the slip layer is in the aforementioned Item 1 or 2 is ^{0.10μg / cm 2 ~1.0μg / cm 2} .

[4] The heat-fusible resin layer is formed of a single layer, and the content of the surfactant in the heat-fusible resin layer is 500 ppm to 5000 ppm. Exterior material for power storage devices.

[5] In any one of the above items 1 to 3, wherein the heat-fusible resin layer is formed of a plurality of layers, and the content of the surfactant in the outermost outermost layer of the plurality of layers is 500 ppm to 5000 ppm. The exterior material for the electricity storage device described.

[6] The exterior material for an electricity storage device according to any one of items 1 to 5, wherein the surfactant is a nonionic surfactant.

[7] The exterior material for an electricity storage device according to any one of the above items 1 to 6, wherein the heat-fusible resin layer is formed of an unstretched heat-fusible resin film.

[8] The exterior material for an electricity storage device according to any one of items 1 to 7, wherein the heat-fusible resin layer is formed of a polyolefin resin containing the fatty acid amide lubricant and an antiblocking agent.

[9] A power storage device body,
The exterior material according to any one of items 1 to 8 above,
An electricity storage device, wherein the electricity storage device body is covered with the exterior material.

In the invention [1], since the slip layer (sliding layer) containing the fatty acid amide lubricant is formed on the outer surface, the moldability is excellent. In addition, heat aging treatment is performed during manufacturing, but the orientation (hydrophobic groups are aligned on the surface side) that occurs in the fatty acid amide lubricant in the slip layer when heat aging treatment is obstructed by the surfactant contained in the slip layer. Therefore, it is presumed that at least a part of the hydrophilic group of the lubricant can be exposed on the surface side and the wettability is improved even when the fatty acid amide lubricant is present (estimated but not certain). .. Since the wettability is improved in this way, the tape adhesion is good.

In the invention [2], since the slip layer containing the fatty acid amide lubricant is formed on the outer surface, the moldability is excellent. In addition, heat aging treatment is performed during manufacturing, but the orientation (hydrophobic groups are aligned on the surface side) that occurs in the fatty acid amide lubricant in the slip layer when heat aging treatment is obstructed by the surfactant contained in the slip layer. Therefore, it is presumed that at least a part of the hydrophilic group of the lubricant can be exposed on the surface side and the wettability is improved even when the fatty acid amide lubricant is present (estimated but not certain). .. Since the wettability is improved in this way, the tape adhesion is good.

In the invention [3], 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 inventions [4] and [5], the content of the surfactant in the slip layer is in a suitable range, and the orientation occurs in the fatty acid amide lubricant when heat-aged (the hydrophobic groups are aligned on the surface side). Is sufficiently inhibited and the wettability is further improved, so that the tape adhesion can be further improved.

In the invention [6], since the nonionic surfactant is used, the nonionic surfactant can reduce the influence on the electrolyte and the like.

In the invention [7], since the heat-fusible resin layer is formed of an unstretched film and has low crystallinity, the fatty acid amide lubricant and the surfactant are not included in the heat-fusible resin layer during the heat aging treatment. Easy to bleed out from. Therefore, when the exterior material is wound into a roll at the time of production and the heat aging treatment is performed in this wound state, the fatty acid amide lubricant and the surfactant are sufficiently transferred from the heat-fusible resin layer to form the slip layer. As a result, the moldability can be further improved, and the tape adhesion can be further improved.

In the invention [8], by containing the anti-blocking agent in the heat-fusible resin layer, fine irregularities are formed on the surface of the heat-fusible resin layer, and the slipperiness is improved. As a result, the amount of the fatty acid amide-based lubricant added to the heat-fusible resin layer can be reduced, so that the transfer amount of the lubricant in the slip layer can be reduced, and the hydrophobic group of the fatty acid amide-based lubricant in the slip layer can be reduced. Since the number of parts can be reduced, the tape adhesion can be further improved.

According to the invention [9], 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 electrical storage devices which concerns on this invention. It is sectional drawing which shows other embodiment of the exterior material for electric 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 portion, 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 an 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. The heat-fusible resin layer 3 contains a fatty acid amide lubricant and a surfactant, and a slip layer (sliding layer) containing the fatty acid amide lubricant and a surfactant on the outer surface of the heat resistant resin layer 2. 11 is formed. Since the slip layer 11 containing the fatty acid amide lubricant is formed on the outer surface of the exterior material 1 for an electricity storage device, the formability is excellent. Further, the heat aging treatment is carried out at the time of production, but the orientation (having the hydrophobic groups aligned on the surface side) occurring in the fatty acid amide-based lubricant of the slip layer when subjected to the heat aging treatment depends on the surfactant contained in the slip layer 11. Since it is inhibited, at least a part of the hydrophilic group of the lubricant can be exposed on the surface side, and it is presumed that the wettability is improved even if the fatty acid amide lubricant is present (estimated but not certain. ). Since the wettability is improved in this way, the tape adhesion is good.

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 heat-fusible resin layer 3 contains a fatty acid amide lubricant and a surfactant, the protective resin layer 12 is formed on the outer surface of the heat-resistant resin layer 2, and the outer surface of the protective resin layer 12 is formed. This is a configuration in which a slip layer 11 containing a fatty acid amide lubricant and a surfactant is formed. Since the slip layer 11 containing the fatty acid amide lubricant is formed on the outer surface of the exterior material 1 for an electricity storage device, the formability is excellent. Further, since the slip layer 11 also contains a surfactant in addition to the fatty acid amide lubricant, the slip layer 11 has good wettability and tape adhesion as in the above embodiment.

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 the heat-fusible resin layer (inner layer) is formed on the other surface (lower surface) of the metal foil layer 4 via the 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. Such a fatty acid amide lubricant is included 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 aging treatment at a predetermined temperature in the wound state. The fatty acid in the heat-fusible resin layer 3 is obtained by the aging treatment in the wound state. The amide lubricant and the surfactant are 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 the fatty acid amide lubricant and the surfactant (FIGS. 1 and 2). reference). 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. That is, when the heat-fusible resin layer 3 is formed as a single layer, the content of the fatty acid amide lubricant in the heat-fusible resin layer is preferably set in the range of 500 ppm to 7,000 ppm. When the heat-fusible resin layer 3 is formed of a plurality of layers, the content of the fatty acid amide-based lubricant in the outermost (outermost side in FIGS. 1 and 2) outermost layer of the plurality of layers. Is preferably set in the range of 500 ppm to 7000 ppm. When the heat fusible resin layer 3 is formed of a plurality of layers, the content of the fatty acid amide lubricant in the outermost layer of the heat fusible resin layer 3 affects the transfer amount of the fatty acid amide lubricant. Exert.

In the present invention, the content of the surfactant in the heat-fusible resin layer 3 is preferably set in the range of 500 ppm to 5000 ppm, more preferably 1000 ppm to 3000 ppm. When the heat-fusible resin layer 3 is formed as a single layer, the content of the surfactant in the heat-fusible resin layer is preferably 500 ppm to 5000 ppm. When the heat-fusible resin layer 3 is formed of a plurality of layers, the content of the surfactant in the outermost (outermost lower side in FIGS. 1 and 2) outermost layer of the plurality of layers is It is preferably set to 500 ppm to 5000 ppm. When the heat-fusible resin layer 3 is formed of a plurality of layers, the content of the surfactant in the outermost layer of the heat-fusible resin layer 3 affects the transfer amount of the surfactant. ..

Examples of the surfactant include nonionic surfactants (nonionic surfactants), anionic surfactants, cationic surfactants and amphoteric surfactants. Among these, nonionic surfactants are also included. It is preferable to use a system surfactant. This is because they are nonionic and do not interfere with the electrolyte or the like of the contents.

The nonionic surfactant is not particularly limited, and examples thereof include glycerin fatty acid ester or its ethylene oxide adduct, polyglycerin fatty acid ester (diglycerin laurate, diglycerin oleate, etc.), polyoxyalkylene alkyl. Ether, polyoxyalkylene dialkyl ether, polyoxyalkylene alkyl ester, polyoxyalkylene alkylaryl ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbit fatty acid ester, polyoxyethylene glycol fatty acid ester, polyoxyethylene castor Oils, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkylamines, higher fatty acid alkanolamides, alkyl glycosides, alkyl amine oxides, polyethylene glycol monostearate and the like can be mentioned.

As the surfactant, it is preferable to use one having an HLB value of 3 to 18, and it is particularly preferable to use one having an HLB value of 5 to 10.

In the present invention, the outer layer 2 is formed of a heat resistant resin layer. As the heat-resistant resin that constitutes the heat-resistant resin layer 2, a heat-resistant resin that does not melt at the heat-sealing temperature when the exterior material 1 is heat-sealed is used. As the heat-resistant resin, it is preferable to use a heat-resistant resin having a melting point higher by 10° C. or more than the melting point of the heat-fusible resin forming the heat-fusible resin layer 3. 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, a stretched polyester film, and the like. 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, but 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 and draw forming can be reduced and moldability can be improved. You can

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 resins, urethane resins, acrylic ester resins, methacrylic ester resins and polyethyleneimine resins. Can be formed by applying and drying by a spray coating method, a gravure roll coating method, a reverse roll coating method, a lip coating method, or the like. Alternatively, it may be formed by applying and curing a coating liquid containing a base material containing a urethane resin and a curing agent containing a polyisocyanate. The thickness of the protective resin layer 12 is preferably set to 2 μm to 5 μm. Examples of the resin that constitutes the protective resin layer 12 include polyester resins, polyolefin resins, fluororesins, and phenoxy resins, 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, fluorine-containing polyethylene wax, etc. 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 and the surfactant 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. It is preferably one. Alternatively, the fatty acid amide lubricant and the surfactant are contained by applying a coating solution containing the fatty acid amide lubricant and the surfactant on the surface of the heat resistant resin layer 2 or the surface of the protective resin layer 12. The slip layer 11 may be formed. 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 the penetration 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 due to the contents (such as the electrolytic solution of the battery). For example, the metal foil is subjected to 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,
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 chromium (III) salts;
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, 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 even to 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, and maleic anhydride modified polyethylene.

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. You can have it.

The heat-fusible resin layer 3 contains a fatty acid amide lubricant and a surfactant, but it may also contain an anti-blocking agent (inorganic particles, resin particles, etc.). By containing an anti-blocking agent, unevenness is formed on the surface of the heat-fusible resin layer, and slippage can be secured even if the amount of the fatty acid amide lubricant added is reduced. It is possible to suppress the transfer amount and to reduce the hydrophobic group portion of the fatty acid amide lubricant in the slip layer, so that the tape adhesion can be further improved.

The anti-blocking agent is not particularly limited, but examples thereof include inorganic particles and resin particles. The inorganic particles are not particularly limited, for example, inorganic oxide particles (silica particles, alumina particles, titanium oxide particles, etc.), inorganic carbonate particles (calcium carbonate particles, barium carbonate particles, etc.), inorganic Examples thereof include silicate particles (aluminum silicate particles, talc particles, kaolin particles, etc.). The resin particles are not particularly limited, and examples thereof include acrylic resin particles, polyolefin resin particles (polyethylene resin particles, polypropylene resin particles, etc.), polystyrene resin particles, and the like. The average particle size of the anti-blocking agent is preferably 0.5 μm to 4 μm in consideration of the uneven shape of the surface and prevention of falling.

The thickness of the outer adhesive layer 5 is preferably 1 μm to 5 μm. The outer adhesive is not particularly limited, and 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, etc.) 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 the present embodiment, as shown in FIGS. 3 and 4, the exterior case 15 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 body portion (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, and the electricity storage device body portion 31. The heat-sealable resin layer 3 of the present invention is placed on the top of the flat outer-sheath resin layer 3 with the heat-fusible resin layer 3 side 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 of the housing case 14 inside the housing recess 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 embodiment, the exterior member 15 has a configuration including the exterior case 14 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. 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 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 layer containing ethylene-propylene random copolymer, 1000 ppm erucic acid amide (lubricant), 2000 ppm silica particles (anti-blocking agent) and 2000 ppm diglycerin laurate (surfactant). A second unstretched film having a thickness of 28 μm, which comprises a first unstretched film, an ethylene-propylene block copolymer, 1000 ppm erucic acid amide (lubricant) and 2000 ppm diglycerin laurate (surfactant), ethylene. A third unstretched 6 μm thick containing propylene random copolymer, 1000 ppm erucic acid amide (lubricant), 2000 ppm silica particles (antiblocking agent) and 2000 ppm diglycerin laurate (surfactant). After obtaining a sealant film (inner layer) 3 having a thickness of 40 μm by coextrusion using a T die so that the films are laminated in this order in three layers, the first unstretched film surface of the sealant film 3 is obtained. Is laminated on the other surface of the aluminum foil 4 after the dry lamination through a two-component curing type maleic acid-modified polypropylene adhesive (thickness 3 μm), a rubber nip roll and a laminating roll heated to 100° C. It is dry-laminated by being sandwiched between and by press-bonding, and thereafter, 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. By aging (heating) at 10° C. for 10 days, the lubricant (erucic acid amide) and the surfactant (diglycerin laurate) are transferred from the sealant film (inner layer) to the surface of the nylon film 2 to form the slip layer 11. The formed exterior material 1 for an electricity storage device having the configuration shown in FIG. 1 was obtained. The slip layer 11 had a lubricant amount of 0.30 μg/cm ² .

<Example 2>
In the same manner as in Example 1 except that the content of the erucic acid amide (lubricant) in the first to third unstretched films was set to 3000 ppm, the lubricant and the surfactant from the sealant film (inner layer) to the nylon film 2 were obtained. An outer packaging material 1 for an electricity storage device having a structure shown in FIG. 1 which was transferred to the surface and formed with a slip layer 11 was obtained. The slip layer 11 had an amount of lubricant of 0.50 μg/cm ² .

<Example 3>
In the same manner as in Example 1 except that the content of erucic acid amide (lubricant) in the first to third unstretched films was set to 2000 ppm and the content of diglycerin laurate (surfactant) was set to 1000 ppm. Then, the lubricant and the surfactant were transferred from the sealant film (inner layer) to the surface of the nylon film 2 to form the slip layer 11, so that the exterior material 1 for an electricity storage device having the configuration shown in FIG. 1 was obtained. The slip layer 11 had a lubricant amount of 0.30 μg/cm ² .

<Example 4>
In the same manner as in Example 1 except that the erucamide amide (lubricant) content in the first to third unstretched films was set to 2000 ppm and the diglycerin laurate (surfactant) content was set to 300 ppm. Then, the lubricant and the surfactant were transferred from the sealant film (inner layer) to the surface of the nylon film 2 to form the slip layer 11, so that the exterior material 1 for an electricity storage device having the configuration shown in FIG. 1 was obtained. The amount of lubricant in the slip layer 11 was 0.20 μg/cm ² .

<Example 5>
In the same manner as in Example 1 except that the content of erucic acid amide (lubricant) in the first to third unstretched films was set to 2000 ppm and the content of diglycerin laurate (surfactant) was set to 4000 ppm. Then, the lubricant and the surfactant were transferred from the sealant film (inner layer) to the surface of the nylon film 2 to form the slip layer 11, so that the exterior material 1 for an electricity storage device having the configuration shown in FIG. 1 was obtained. The slip layer 11 had a lubricant amount of 0.40 μg/cm ² .

<Example 6>
In the same manner as in Example 1 except that the content of erucamide (lubricant) in the first to third unstretched films was set to 2000 ppm and the content of diglycerin laurate (surfactant) was set to 6000 ppm. Then, the lubricant and the surfactant were transferred from the sealant film (inner layer) to the surface of the nylon film 2 to form the slip layer 11, so that the exterior material 1 for an electricity storage device having the configuration shown in FIG. 1 was obtained. The slip layer 11 had an amount of lubricant of 0.50 μg/cm ² .

<Example 7>
In the same manner as in Example 1 except that the content of erucic acid amide (lubricant) in the first to third unstretched films was set to 5000 ppm and the content of diglycerin laurate (surfactant) was set to 2000 ppm. Then, the lubricant and the surfactant were transferred from the sealant film (inner layer) to the surface of the nylon film 2 to form the slip layer 11, so that the exterior material 1 for an electricity storage device having the configuration shown in FIG. 1 was obtained. The amount of lubricant in the slip layer 11 was 0.80 μg/cm ² .

<Example 8>
In the same manner as in Example 1 except that the erucamide amide (lubricant) content in the first to third unstretched films was set to 8000 ppm and the diglycerin laurate (surfactant) content was set to 2000 ppm. Then, the lubricant and the surfactant were transferred from the sealant film (inner layer) to the surface of the nylon film 2 to form the slip layer 11, so that the exterior material 1 for an electricity storage device having the configuration shown in FIG. 1 was obtained. The amount of lubricant in the slip layer 11 was 1.20 μg/cm ² .

<Comparative Example 1>
An exterior material for an electricity storage device was obtained in the same manner as in Example 1 except that the content of the erucic acid amide (lubricant) in the first to third unstretched films was set to 0 ppm (no lubricant was added). .. The amount of lubricant in the slip layer was 0 μg/cm ² .

<Comparative example 2>
The content of erucic acid amide (lubricant) in the first to third unstretched films was set to 4000 ppm, and the content of diglycerin laurate (surfactant) was set to 0 ppm (a structure in which no surfactant was added was set. Other than the above), an outer casing material for an electricity storage device was obtained in the same manner as in Example 1. The amount of lubricant in the slip layer was 0.50 μg/cm ² .

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 out 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 are overlapped so that the side with the slip layer is on the inside, and the peripheral portions of each other are joined together. Was heat-sealed at a heat-sealing temperature of 250° C. and a sealing width of 5 mm to prepare a bag. 1 mL of acetone was injected into the inner space of the bag using a syringe, and the bag was left for 3 minutes while the inner surface of the bag was in contact with acetone, and then the acetone in the bag was extracted. 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 with a press molding machine to a length of 150 mm × width of 150 mm × 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 with 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 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 sufficiently attached to the exterior material. Then, it was left to stand in a room at 25° C. for 1 hour. Next, according to JIS K6854-2 (1999), the test piece (exterior material) was sandwiched and fixed by one chuck using a Shimadzu Strograph AGS-5kNX, and an acrylic plate was fixed by the other chuck. (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 6 N/5 mm or more "O" (pass)... Peel strength is 5 N/5 mm or more and less than 6 N/5 mm "X"... Peel strength is less than 5 N/5 mm ..

As is apparent from the table, the exterior materials of Examples 1 to 8 of the present invention had good moldability and good tape adhesion.

On the other hand, in Comparative Examples 1 and 2 which deviate from the specified range of the present invention, at least one or more of “moldability”, “wettability” and “tape adhesion” was poorly evaluated.

Specific examples of the exterior material for an electricity storage device according to the present invention include:
-Used as an exterior 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 electricity storage device according to the present invention includes an all-solid-state battery in addition to the electricity 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 (9)

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,
The heat-fusible resin layer contains a fatty acid amide lubricant and a surfactant,
An exterior material for an electricity storage device, wherein a slip layer containing a fatty acid amide lubricant and a surfactant is formed on the outer surface of the heat resistant resin layer. 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,
The heat-fusible resin layer contains a fatty acid amide lubricant and a surfactant,
A protective material layer is formed on the outer surface of the heat resistant resin layer, and a slip layer containing a fatty acid amide lubricant and a surfactant is formed on the outer surface of the protective resin layer. Exterior material for a power storage device according to claim 1 or 2 content of the fatty acid amide lubricant is 0.10μg / cm ² ~1.0μg / cm ² in the slip layer. The electricity storage device according to claim 1, wherein the heat-fusible resin layer is formed as a single layer, and the content of the surfactant in the heat-fusible resin layer is 500 ppm to 5000 ppm. Exterior material for. The heat-fusible resin layer is formed of a plurality of layers, and the content rate of the surfactant in the outermost outermost layer of the plurality of layers is 500 ppm to 5000 ppm. Exterior material for power storage devices. The exterior material for an electricity storage device according to claim 1, wherein the surfactant is a nonionic surfactant. The exterior material for an electricity storage device according to claim 1, wherein the heat-fusible resin layer is formed of an unstretched heat-fusible resin film. The exterior material for an electricity storage device according to claim 1, wherein the heat-fusible resin layer is formed of a polyolefin resin containing the fatty acid amide lubricant and an antiblocking agent. An electricity storage device body,
An exterior material according to any one of claims 1 to 8, comprising:
An electricity storage device, wherein the electricity storage device body is covered with the exterior material.

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