JP2020064739A - External case for power storage device and manufacturing method thereof - Google Patents

Abstract

To provide an external case for a power storage device, which has an outer layer having good tape adhesion and is in a good molded state.SOLUTION: An external case 10 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 arranged between these two layers, and the heat-fusible resin layer 3 contains a lubricant, the content of the lubricant in the heat-fusible resin layer 3 is 200 ppm to 7,000 ppm, and the amount of the lubricant on the outer surface of the heat-resistant resin layer 2 is less than 0.1 μg/cm, and the wetting tension of the outer surface of the heat resistant resin layer 2 is 33 mN/m or more.SELECTED DRAWING: Figure 2

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 an exterior body and a manufacturing method thereof.

  In addition, in this specification and a claim, the term "wetting tension" means the wetting index (surface tension) measured based on JISK6768-1999.

  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 composed of 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, 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 breaks, 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 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. . That is, it is desired that the lubricant is present on the outer surface of the exterior material from the viewpoint of improving moldability, while it is necessary to avoid the presence of the lubricant on the outer surface of the exterior material from the viewpoint of ensuring tape adhesion. was there.

  The present invention has been made in view of the above technical background, and an object of the present invention is to provide an outer case for an electricity storage device that has an outer layer with good tape adhesion and is in a good molded state, and a method for manufacturing the same. To do.

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

[1] A molding case for an exterior material, comprising 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 lubricant, the content of the lubricant in the heat-fusible resin layer is 200ppm ~ 7000ppm,
The amount of lubricant on the outer surface of the heat resistant resin layer is less than 0.1 μg / cm ² ,
An outer case for an electricity storage device, wherein the outer surface of the heat resistant resin layer has a wetting tension of 33 mN / m or more.

  [2] The exterior case for an electricity storage device according to item 1, wherein the molding depth of the molding case is 3 mm or more.

  [3] The heat-fusible resin layer comprises a laminate of a plurality of heat-fusible resin films, and the heat-fusible resin film is formed of a propylene-based resin containing propylene as a main component. The outer case for an electricity storage device according to 1 or 2.

[4] A heat-resistant resin layer as an outer layer, a heat-fusible resin layer containing a lubricant as an inner layer, and a metal foil layer arranged between these two layers are used as an exterior material. A step of obtaining a roll body by stacking in a roll shape in a mode in which the fusible resin layer and the heat resistant resin layer are in contact with each other;
A step of drawing out the exterior material from the roll body and performing molding of the extracted exterior material to obtain an exterior case for an electricity storage device;
A method of manufacturing an outer case for an electricity storage device, comprising: a step of performing corona treatment or flame treatment on a surface of an outer layer of the outer case for the electricity storage device.

In the invention [1], the amount of lubricant on the outer surface of the heat-resistant resin layer is less than 0.1 μg / cm ² , and the wetting tension on the outer surface is 33 mN / m or more. It is possible to obtain an outer case (molding case) having good tape adhesion, which is sufficiently adhered. Moreover, since the lubricant content in the heat-fusible resin layer is 200 ppm to 7000 ppm, an appropriate amount of lubricant is transferred to the surface of the outer layer, and good molding without pinholes or cracks was performed. A molded case (exterior case) can be provided.

  In the invention [2], an outer case (molding case) having good tape adhesion can be obtained even when deep molding having a molding depth of 3 mm or more is performed.

  In the invention [3], since it is easy to control the movement of the lubricant in the heat-fusible resin layer, a molded case (exterior case) having a better molded state can be obtained.

  In the invention of [4], by performing corona treatment or flame treatment on the surface of the outer layer, the lubricant on the surface of the outer layer can be removed and the wettability of the surface can be improved. The tape adhesion to the surface of the outer layer can be significantly improved.

It is sectional drawing which shows one Embodiment of the exterior material for electric storage devices (before shaping | molding). It is a perspective view which shows an example of the exterior body (exterior case) for electric storage devices of this invention obtained by shape | molding the exterior material of FIG.

The outer case 10 for an electricity storage device according to the present invention 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 these layers. The heat fusible resin layer 3 contains a lubricant, the content of the lubricant in the heat fusible resin layer is 200 ppm to 7000 ppm, and the heat resistance is The lubricant amount on the outer surface of the resin layer 2 is less than 0.1 μg / cm ² , and the wetting tension on the outer surface of the heat resistant resin layer 2 is 33 mN / m or more.

According to the present invention, the amount of lubricant on the outer surface 2a of the heat resistant resin layer (outer layer) 2 is less than 0.1 μg / cm ² , and the wetting tension of the outer surface 2a is 33 mN / m or more. An outer case (molding case) having good tape adhesion, in which the fixing tape is sufficiently adhered to the surface of 2, can be obtained. Further, since the content of the lubricant in the heat-fusible resin layer 3 is 200 ppm to 7000 ppm, an appropriate amount of the lubricant is transferred to the surface of the outer layer 2 during molding, and pinholes and cracks are not generated. A molded case (exterior case) that has been molded can be provided.

  The lubricant content in the heat-fusible resin layer is preferably 500 ppm to 6000 ppm, more preferably 800 ppm to 4000 ppm.

The amount of lubricant (after corona treatment or flame treatment) on the outer surface 2a of the heat resistant resin layer 2 needs to be less than 0.1 μg / cm ² . If it is 0.1 μg / cm ² or more, the tape adhesion is lowered. Above all, the amount of lubricant on the outer surface of the heat resistant resin layer 2 is preferably 0.08 μg / cm ² or less, and more preferably 0.06 μg / cm ² or less.

  The wetting tension of the outer surface of the heat resistant resin layer 2 needs to be 33 mN / m or more. If it is less than 33 mN / m, the tape adhesiveness will decrease. Among them, the wetting tension of the outer surface of the heat resistant resin layer 2 is preferably 45 mN / m or more, more preferably 45 mN / m to 59 mN / m, and more preferably 50 mN / m to 59 mN / m. Is particularly preferable.

  In the above-mentioned embodiment, the heat-resistant resin layer (outer layer) 2 is laminated and integrated on one surface (upper surface) of the metal foil layer 4 via the outer adhesive layer (first adhesive layer) 5 in the exterior material 1. And the heat-fusible resin layer (inner layer) 3 was laminated and integrated on the other surface (lower surface) of the metal foil layer 4 with the inner adhesive layer (second adhesive layer) 6 interposed therebetween. The configuration (see FIG. 1).

An example of a method for manufacturing the outer case 10 for an electricity storage device according to the present invention will be described below. An exterior material 1 including a heat-resistant resin layer 2 as an outer layer, a heat-fusible resin layer 3 containing a lubricant as an inner layer, and a metal foil layer 4 disposed between these layers is prepared. . The lubricant amount on the outer surface of the heat-resistant resin layer of the outer package 1 (i.e. corona pretreatment or flame pretreatment) is preferably set to ^{0.1μg / cm 2 ~1.0μg / cm 2} . If it is less than 0.1 μg / cm ^2, it is difficult to obtain sufficient moldability, and if it exceeds 1.0 μg / cm ² , the lubricant on the outer surface of the heat resistant resin layer cannot be sufficiently removed even if corona treatment or flame treatment is performed. Without tape adhesion. In addition, the lubricant content in the heat-fusible resin layer 3 of the exterior material 1 (that is, before corona treatment or flame treatment) is preferably set to 100 ppm to 6000 ppm.

  Next, the outer packaging material is stacked in a roll shape in a mode in which the heat-fusible resin layer 3 and the heat resistant resin layer 2 are in contact with each other to obtain a roll body. Since the heat-fusible resin layer and the heat-resistant resin layer are stacked in a roll shape in a state of contacting each other, the lubricant of the heat-fusible resin layer is transferred to the surface of the heat-resistant resin layer.

  Next, the exterior material is pulled out from the roll body, and the drawn exterior material 1 is molded to obtain the electricity storage device exterior case 10. Since the lubricant is also present on the surface of the heat-resistant resin layer by the transfer, the molding is performed in a good state (the molding has no molding defects such as pinholes and cracks). Examples of the molding method include deep drawing molding, overhang molding, and embossing molding.

Next, the surface of the heat resistant resin layer (outer layer) 2 of the outer case 10 for the electricity storage device is subjected to corona treatment or flame treatment (treatment process). By subjecting the surface of the outer layer to corona treatment or flame treatment in this way, the lubricant on the surface of the outer layer can be removed and the wettability of the surface can be improved. It is possible to remarkably improve the tape adhesiveness. By performing the corona treatment or flame treatment, the lubricant on the surface of the outer layer is removed so that the amount of lubricant on the outer surface of the outer layer 2 is less than 0.1 μg / cm ² . Above all, the amount of lubricant on the outer surface of the outer layer 2 is preferably 0.08 μg / cm ² or less, and particularly preferably 0.06 μg / cm ² or less. Further, the wetting tension of the outer surface 2a of the outer layer 2 can be set to 33 mN / m or more by subjecting the surface of the outer layer 2 to corona treatment or flame treatment.

  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 constituting 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, a biaxially stretched polyamide film such as a biaxially stretched nylon film, a biaxially stretched polybutylene terephthalate (PBT) film, a biaxially stretched polyethylene terephthalate (PET) film or a biaxially stretched polyethylene film is used. It is preferable to use a phthalate (PEN) film having a hot water shrinkage of 0.1% to 12%. 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 and the like. The heat-resistant resin film layer 2 may be formed of a single layer (single stretched film), or may be, for example, a multi-layer (stretched PET film / stretched nylon film) made of 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 7 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

  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 thickness of the metal foil layer 4 is preferably 10 μm to 120 μm. When it is 10 μm or more, pinholes can be prevented from being generated during rolling when manufacturing a metal foil, and when it is 120 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. Above all, the thickness of the metal foil layer 4 is particularly preferably 10 μm to 80 μm.

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 degreased metal foil,
1) phosphoric acid,
With chromic acid,
An aqueous solution of a mixture containing at least one compound selected from the group consisting of fluoride metal salts and fluoride non-metal salts 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 a chromium (III) salt, 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 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; 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 (EAA), 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 seal 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.

  In the present invention, the lubricant is not particularly limited, for example, saturated fatty acid amide, unsaturated fatty acid amide, substituted amide, methylolamide, saturated fatty acid bisamide, unsaturated fatty acid bisamide, fatty acid ester amide, aromatic Examples include bisamides.

  The saturated fatty acid amide is not particularly limited, and examples thereof 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.

  The substituted amide is not particularly limited, and examples thereof include N-oleylpalmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid. Examples include amides. The methylolamide is not particularly limited, and examples thereof include methylol stearic acid amide.

  The saturated fatty acid bisamide is not particularly limited, and examples thereof include methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, and ethylene. Examples include bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N, N'-distearyl adipic acid amide, and N, N'-distearyl sebacic acid amide. To be

  The unsaturated fatty acid bisamide is not particularly limited, and examples thereof include ethylene bis oleic acid amide, ethylene bis erucic acid amide, hexamethylene bis oleic acid amide, N, N′-dioleyl sebacic acid amide, N , N′-dioleyl adipamide and the like.

  The fatty acid ester amide is not particularly limited, and examples thereof include stearoamide ethyl stearate. The aromatic bisamide is not particularly limited, and examples thereof include m-xylylenebisstearic acid amide, m-xylylenebishydroxystearic acid amide, and N, N′-cystearylisophthalic acid amide. Can be mentioned.

  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 aluminum foil 4 having a thickness of 40 μm, and then dried at 180 ° C. , A chemical conversion film was formed. The amount of chromium deposited on this chemical conversion coating was 10 mg / m ² per side.

  Then, a biaxially stretched 6-nylon film 2 having a thickness of 25 μm was dry-laminated (bonded) on one surface of the chemical conversion-treated aluminum foil 4 via a two-component curing type urethane adhesive 5.

  Next, a 4.5 μm-thick first unstretched film containing an ethylene-propylene random copolymer, 1000 ppm of behenamide and 3000 ppm of silica particles (anti-blocking agent), an ethylene-propylene block copolymer. And a second unstretched film having a thickness of 21 μm containing 1000 ppm of erucic acid amide, an ethylene-propylene random copolymer, 1000 ppm of behenic acid amide and 3000 ppm of silica particles (anti-blocking agent). After obtaining a sealant film (inner layer) 3 by coextruding a first unstretched film having a thickness of 4.5 μm using a T-die so that three layers are laminated in this order, 1 Before the non-stretched film surface with olefin adhesive (thickness 2μm) Dry lamination is performed by superposing it on the other surface of the aluminum foil 4 after dry lamination, sandwiching it between a rubber nip roll and a laminating roll heated to 100 ° C. and press-bonding, and then at 40 ° C. for 10 days. By aging (heating), the exterior material 1 for an electricity storage device having the configuration shown in FIG. 1 was obtained.

  The obtained exterior material was cut to obtain a sheet having a size of 200 mm length × 200 mm width. A molded product having a length of 150 mm, a width of 150 mm, and a depth of 5 mm was formed on this sheet using a press molding machine (press speed: 20 spm, wrinkle suppressing pressure: 1.60 MPa). The surface of the outer layer 2 of the obtained molded product was subjected to corona treatment (voltage 12 kV, treatment time 0.1 s) to obtain the electricity storage device exterior case 10 shown in FIG. 2.

<Example 2>
As the sealant film 3, a 4.5 μm-thick first unstretched film containing an ethylene-propylene random copolymer, 2000 ppm behenamide and 3000 ppm silica particles (anti-blocking agent), an ethylene-propylene block copolymer. 21 μm thick second unstretched film containing polymer and 2000 ppm erucic acid amide, ethylene-propylene random copolymer, 2000 ppm behenic acid amide and 3000 ppm silica particles (anti-blocking agent) The same procedure as in Example 1 was repeated except that a sealant film obtained by coextrusion using a T die was used so that the first unstretched film having a thickness of 4.5 μm was laminated in this order in three layers. The outer case 10 for an electricity storage device shown in 2 was obtained.

<Example 3>
As the sealant film 3, an ethylene-propylene random copolymer, a first unstretched film having a thickness of 4.5 μm, containing 5000 ppm behenamide and 3000 ppm silica particles (anti-blocking agent), an ethylene-propylene block copolymer. 21 μm thick second unstretched film containing polymer and 5000 ppm erucic acid amide, ethylene-propylene random copolymer, 5000 ppm behenic acid amide and 3000 ppm silica particles (antiblocking agent) Using a sealant film obtained by coextruding a first unstretched film having a thickness of 4.5 μm using a T-die so that three layers are laminated in this order, flame treatment (frame treatment) is used instead of corona treatment. As shown in FIG. 2, the same as Example 1 except that the steps were performed. To give the outer case 10 for the photovoltaic device.

<Example 4>
After molding, before carrying out corona treatment, the outer case surface for an electricity storage device 10 shown in FIG. 2 was obtained in the same manner as in Example 1 except that the surface of the outer layer was wiped off using an ethanol-impregnated nonwoven fabric. .

<Comparative Example 1>
As the sealant film 3, a 4.5 μm thick first unstretched film containing an ethylene-propylene random copolymer, 1000 ppm behenamide and 3000 ppm silica particles (anti-blocking agent), an ethylene-propylene block copolymer. 21 μm thick second unstretched film containing polymer and 1000 ppm erucic acid amide, ethylene-propylene random copolymer, 1000 ppm behenic acid amide and 3000 ppm silica particles (antiblocking agent) With the use of a sealant film obtained by coextrusion using a T die so that the first unstretched film having a thickness of 4.5 μm is laminated in this order in three layers, and no corona treatment is performed, In the same manner as in Example 1, an outer case for an electricity storage device It was obtained.

<Comparative example 2>
As the sealant film 3, a 4.5 μm-thick first unstretched film containing an ethylene-propylene random copolymer, 400 ppm behenamide and 3000 ppm silica particles (anti-blocking agent), an ethylene-propylene block copolymer. 21 μm thick second unstretched film containing polymer and 400 ppm erucic acid amide, ethylene-propylene random copolymer, 400 ppm behenic acid amide and 3000 ppm silica particles (antiblocking agent) With the use of a sealant film obtained by coextrusion using a T die so that the first unstretched film having a thickness of 4.5 μm is laminated in this order in three layers, and no corona treatment is performed, An outer case for an electricity storage device was obtained in the same manner as in Example 1. .

<Comparative example 3>
As the sealant film 3, a 4.5 μm-thick first unstretched film containing an ethylene-propylene random copolymer, 100 ppm behenamide and 3000 ppm silica particles (anti-blocking agent), an ethylene-propylene block copolymer. 21 μm thick second unstretched film containing polymer and 100 ppm erucic acid amide, ethylene-propylene random copolymer, 100 ppm behenic acid amide and 3000 ppm silica particles (anti-blocking agent) With the use of a sealant film obtained by coextrusion using a T die so that the first unstretched film having a thickness of 4.5 μm is laminated in this order in three layers, and no corona treatment is performed, An outer case for an electricity storage device was obtained in the same manner as in Example 1. .

<Comparative example 4>
As the sealant film 3, a 4.5 μm-thick first unstretched film containing an ethylene-propylene random copolymer, 9000 ppm of behenamide and 3000 ppm of silica particles (anti-blocking agent), an ethylene-propylene block copolymer. 21 μm thick second unstretched film containing polymer and 9000 ppm erucic acid amide, ethylene-propylene random copolymer, 9000 ppm behenic acid amide and 3000 ppm silica particles (anti-blocking agent) With the use of a sealant film obtained by coextrusion using a T die so that the first unstretched film having a thickness of 4.5 μm is laminated in this order in three layers, and no corona treatment is performed, In the same manner as in Example 1, an outer case for an electricity storage device It was obtained.

  With respect to the exterior case for an electricity storage device obtained as described above, the amount of lubricant present on the surface of the outer layer was evaluated, the wetting tension (wetting index) of the surface of the outer layer was measured, and the moldability, appearance and tape were measured. The adhesion was evaluated.

<Evaluation method of the amount of lubricant present on the surface of the outer layer>
After cutting out two rectangular test pieces of 100 mm in length × 100 mm in width from the outer case 10 for each electricity storage device, these two test pieces were overlapped so that the outer layers were on the inside, and The peripheral portions were heat-sealed at a heat-sealing temperature of 250 ° C. with a sealing width of 5 mm to produce 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 component contained in the extracted liquid was measured and analyzed using a gas chromatograph to determine the amount of lubricant (μg / cm ² ) present on the surface 2a of the outer layer 2 of the outer case 10.

<Wet tension measurement method>
Based on JIS K6768-1999, the wetting index (surface tension) of the surface of the outer layer of the outer case for each electricity storage device was measured.

<Moldability evaluation method>
The exterior material 1 was molded with 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".

<Appearance evaluation method>
The surface of the obtained outer case 10 was visually inspected, and white powder was generated on the surface of the inner layer was "x", and white powder was not generated on the surface of the inner layer was "o". .

<Tape adhesion evaluation method>
A rectangular test piece having a length of 145 mm and a width of 145 mm was sampled from the maximum surface of each outer case for an electricity storage device. After sticking an adhesive tape having a width of 5 mm and a length of 100 mm on the surface of the outer layer 2 in the test piece, the roller was reciprocated 5 times on the adhesive tape while applying a load to the adhesive tape with a roller having a weight of 2 kg. Then, it was left to stand in a room at 25 ° C. for 1 hour. Next, in accordance with JIS K6854-3 (1999), using a Shimadzu Strograph AGS-5kNX, one chuck clamps and fixes the test piece, and the other chuck clamps and fixes an adhesive tape. Then, the 180 ° peel strength 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 clear from the table, the outer cases of Examples 1 to 3 of the present invention were molded well and had good tape adhesion. On the other hand, in Comparative Examples 1 to 4 which deviate from the stipulated range of the present invention, at least one or more of “moldability”, “appearance” and “tape adhesion” was poor. In Comparative Example 3, the tape adhesion was not evaluated because the evaluation result was a poor moldability.

The external case (molding case) for an electricity storage device according to the present invention is, for example, as a specific example,
-Used as an outer case for various power storage devices such as lithium secondary batteries (lithium ion batteries, lithium polymer batteries, etc.), lithium ion capacitors, electric double layer capacitors, all solid state batteries, etc.

1 ... Exterior material 2 ... Heat resistant resin layer (outer layer)
2a ... Outer surface of heat-resistant resin layer 3 ... Heat-fusible resin layer (inner layer)
4 ... Metal foil layer 10 ... Exterior case (molding case)

Claims (4)

A heat-resistant resin layer as an outer layer, a heat-fusible resin layer as an inner layer, and a molding case of an exterior material including a metal foil layer arranged between these layers,
The heat-fusible resin layer contains a lubricant, the content of the lubricant in the heat-fusible resin layer is 200ppm ~ 7000ppm,
The amount of lubricant on the outer surface of the heat resistant resin layer is less than 0.1 μg / cm ² ,
An outer case for an electricity storage device, wherein the outer surface of the heat resistant resin layer has a wetting tension of 33 mN / m or more.   The outer case for an electricity storage device according to claim 1, wherein the molding depth of the molding case is 3 mm or more.   The heat-fusible resin layer comprises a laminate of a plurality of heat-fusible resin films, and the heat-fusible resin film is formed of a propylene-based resin containing propylene as a main component. The outer case for an electricity storage device according to 2. A heat-resistant resin layer as an outer layer, a heat-fusible resin layer containing a lubricant as an inner layer, and an exterior material including a metal foil layer arranged between these layers, the heat-fusible resin A step of obtaining a roll body by stacking in a roll shape in a mode in which the resin layer and the heat resistant resin layer are in contact with each other,
A step of drawing out the exterior material from the roll body and performing molding of the extracted exterior material to obtain an exterior case for an electricity storage device;
A method of manufacturing an outer case for an electricity storage device, comprising: a step of performing corona treatment or flame treatment on a surface of an outer layer of the outer case for the electricity storage device.

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