Battery manufacturing method

Abstract

To provide an outer case for power storage devices which includes an outside layer of satisfactory tape adhesiveness and of which the molding state is satisfactory.SOLUTION: A molding case of an outer material includes a heat-resistant resin layer 2 as an outside layer, a heat-fusible resin layer as an inside layer, and a metal foil layer disposed between both the layers. The heat-fusible layer contains a lubricant, a lubricant content in the heat-fusible layer is 200 ppm to 8,000 ppm and a lubricant amount on an outer surface of the heat-fusible resin layer is 0.10 μg / cm2 to 1.0 μg / cm2. A lubricant amount on an outer surface 2a of the heat-resistance resin layer 2 is less than 0.01 μg / cm2, and a wet tension on the outer surface 2a of the heat-resistant resin layer 2 is 30 mN / m or more.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an exterior body for an electricity storage device such as a battery or capacitor used in portable devices such as a smartphone or tablet, or a battery or capacitor used for storing electricity in hybrid vehicles, electric vehicles, wind power generation, solar power generation, or nighttime electricity, and a method for manufacturing the same.

[0002] In this specification and claims, the term "wet tension" means the wetting index (surface tension) measured in accordance with JIS K6768-1999. [Background technology]

[0003] In recent years, as mobile electrical devices such as smartphones and tablet terminals have become thinner and lighter, laminates consisting of a heat-resistant resin layer / an adhesive layer / a metal foil layer / an adhesive layer / a thermoplastic resin layer (an inner sealant layer) have been used instead of conventional metal cans as the exterior packaging materials for the lithium-ion secondary batteries, lithium polymer secondary batteries, lithium-ion capacitors, electric double-layer capacitors, and other power storage devices installed in these devices. Furthermore, power sources for electric vehicles and the like, large-scale power sources for power storage applications, capacitors, and the like are increasingly being packaged with laminates (exterior packaging materials) having the above-described configurations. The laminates are molded into a three-dimensional shape, such as a roughly rectangular parallelepiped, by stretch molding or deep drawing. Molding into such a three-dimensional shape ensures that a storage space for the main body of the power storage device can be secured.

[0004] Improving the surface slipperiness of the inner sealant layer is required to form such a three-dimensional shape in a good condition without pinholes, fractures, etc. As a method for improving the surface slipperiness of the inner sealant layer to ensure good formability, a configuration in which an antiblocking agent (AB agent) is contained in the inner sealant layer is known (see Patent Document 1).

[0005] Furthermore, it has been proposed to further improve moldability and achieve deeper molding depth by forming a coating layer of a lubricant on the surface of the heat-resistant resin layer (see Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-266811 [Patent Document 2] Patent No. 6222183 Summary of the Invention [Problem to be solved by the invention]

[0007] Batteries packaged in an exterior material are often housed in a housing together with other electronic circuits, etc., and in this case, adhesive tape is attached to the outer surface of the battery exterior material to secure the battery so that it does not come into contact with the other electronic circuits, but there is a problem in that the presence of a lubricant on the outer surface of the exterior material prevents sufficient adhesion of the tape (the adhesive tape easily peels off). That is, from the perspective of improving formability, it is desirable for a lubricant to be present on the outer surface of the exterior material, but from the perspective of ensuring tape adhesion, it is necessary to avoid the presence of a lubricant on the outer surface of the exterior material.

[0008] The present invention has been made in view of this technical background, and aims 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. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides the following means. [1] A molded case for an exterior material comprising a heat-resistant resin layer as an outer layer, a heat-sealable resin layer as an inner layer, and a metal foil layer disposed between these layers, the heat-sealable resin layer contains a lubricant, and the content of the lubricant in the heat-sealable resin layer is 200 ppm to 8000 ppm; The amount of lubricant on the outer surface of the heat-sealable resin layer is 0.10 μg / cm 2 ~1.0μg / cm 2 and The amount of lubricant on the outer surface of the heat-resistant resin layer is 0.01 μg / cm 2 is less than The outer case for an electricity storage device is characterized in that the heat-resistant resin layer has an outer surface with a wet tension of 30 mN / m or more. [2] The outer case for an electricity storage device according to the preceding paragraph 1, wherein the molded case has a molding depth of 3 mm or more. [3] The outer case for an electricity storage device according to item 1 or 2, wherein the heat-sealable resin layer is made of a laminate of a plurality of heat-sealable resin films, and the heat-sealable resin films are formed of a propylene-based resin containing propylene as a main component. [4] A process of stacking an outer packaging material including a heat-resistant resin layer as an outer layer, a heat-sealable resin layer containing a lubricant as an inner layer, and a metal foil layer disposed between these layers in a roll shape in such a manner that the heat-sealable resin layer and the heat-resistant resin layer are in contact with each other to obtain a roll body; a step of unwinding the exterior material from the roll and molding the unwound exterior material to obtain an exterior case for an electricity storage device; and removing the lubricant from the surface of the outer layer of the outer case for the electricity storage device with an organic solvent. [Effects of the Invention]

[0010] In the invention of [1], the amount of lubricant on the outer surface of the heat-resistant resin layer is 0.01 μg / cm 2 Since the wetting tension of the outer surface is 30 mN / m or more, an outer case (molded case) having good tape adhesion can be obtained, in which the fixing tape adheres sufficiently to the surface of the outer layer. Also, the lubricant content in the heat-sealable resin layer is 200 ppm to 8000 ppm, and the amount of lubricant on the outer surface of the heat-sealable resin layer is 0.10 μg / cm 2 ~1.0μg / cm2 Therefore, an appropriate amount of lubricant is transferred to the surface of the outer layer, making it possible to provide a molded case (outer case) that has been well molded without pinholes or cracks. In the invention of [2], even if the molding depth is 3 mm or more, an outer case (molded case) with good tape adhesion can be obtained. In the invention [3], the movement of the lubricant in the heat-sealable resin layer can be easily controlled, so that a molded case (outer case) in a better molded state can be obtained. In the invention [4], the exterior material is stacked in a roll shape in such a manner that the heat-sealable resin layer and the heat-resistant resin layer (outer layer) are in contact with each other, whereby the lubricant is transferred to the surface of the outer layer, and then molding is carried out. After that, the lubricant is removed from the surface of the outer layer with an organic solvent, thereby improving the wettability of the surface, and thereby significantly improving the adhesiveness of the tape to the surface of the outer layer of the exterior case. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing one embodiment of an exterior packaging material for an electricity storage device (before molding). [Figure 2] FIG. 2 is a perspective view showing an example of an exterior body (exterior case) for an electricity storage device of the present invention obtained by molding the exterior material of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] The exterior case 10 for an electricity storage device according to the present invention is a molded case (see FIG. 2) of an exterior material 1 including a heat-resistant resin layer 2 as an outer layer, a heat-sealable resin layer 3 as an inner layer, and a metal foil layer 4 disposed between these two layers, wherein the heat-sealable resin layer 3 contains a lubricant, the content of the lubricant in the heat-sealable resin layer is 200 ppm to 8000 ppm, and the amount of lubricant on the outer surface 3a of the heat-sealable resin layer 3 is 0.10 μg / cm 2 ~1.0μg / cm 2 and the amount of lubricant on the outer surface 2a of the heat-resistant resin layer 2 is 0.01 μg / cm 2and the wet tension of the outer surface 2a of the heat-resistant resin layer 2 is 30 mN / m or more (see FIG. 2).

[0013] According to the present invention, the amount of lubricant on the outer surface 2a of the heat-resistant resin layer (outer layer) 2 is 0.01 μg / cm 2 Since the thickness of the outer surface 2a is less than 30 mN / m and the wet tension of the outer surface 2a is 30 mN / m or more, an outer case (molded case) having good tape adhesion can be obtained, in which a fixing tape adheres sufficiently to the surface of the outer layer 2. Furthermore, the lubricant content in the heat-fusible resin layer 3 is 200 ppm to 8000 ppm, and the amount of lubricant on the outer surface of the heat-fusible resin layer is 0.10 μg / cm 2 ~1.0μg / cm 2 Therefore, an appropriate amount of lubricant is transferred to the surface of the outer layer 2 during molding, making it possible to provide a molded case (outer case) that has been well molded without pinholes or cracks.

[0014] The content of the lubricant in the heat-fusible resin layer is preferably 500 ppm to 6000 ppm, and more preferably 800 ppm to 4000 ppm.

[0015] The amount of lubricant on the outer surface 2a of the heat-resistant resin layer 2 (after wiping with a cloth impregnated with an organic solvent) is 0.01 μg / cm 2 It must be less than 0.01μg / cm 2 Above this, the amount of lubricant on the outer surface 2a of the heat-resistant resin layer 2 is 0.008 μg / cm 2 Preferably, it is 0.006 μg / cm or less. 2 More preferably, it is:

[0016] The wet tension of the outer surface 2a of the heat-resistant resin layer 2 must be 30 mN / m or more. If it is less than 30 mN / m, tape adhesion will decrease. In particular, the wet tension of the outer surface of the heat-resistant resin layer 2 is preferably 35 mN / m or more, and more preferably in the range of 38 mN / m to 59 mN / m.

[0017] In the above embodiment, the packaging material 1 has a configuration in which a heat-resistant resin layer (outer layer) 2 is laminated integrally to one surface (upper surface) of a metal foil layer 4 via an outer adhesive layer (first adhesive layer) 5, and a heat-fusible resin layer (inner layer) 3 is laminated integrally to the other surface (lower surface) of the metal foil layer 4 via an inner adhesive layer (second adhesive layer) 6 (see Figure 1).

[0018] An example of a method for manufacturing the exterior case 10 for an electricity storage device is described below. An exterior material 1 (see FIG. 1) is prepared, which includes a heat-resistant resin layer 2 as an outer layer, a heat-sealable resin layer 3 containing a lubricant as an inner layer, and a metal foil layer 4 disposed between these layers. The amount of lubricant on the outer surface of the heat-resistant resin layer of this exterior material 1 (i.e., before wiping with an organic solvent-impregnated cloth) is 0.10 μg / cm. 2 ~1.0μg / cm 2 It is preferable to set it to 0.10g / cm 2 If it is less than 1.0 μg / cm, it is difficult to obtain sufficient moldability. 2 If the lubricant content exceeds 200 ppm, the lubricant on the outer surface of the heat-resistant resin layer cannot be sufficiently removed even by wiping with an organic solvent-impregnated cloth, resulting in a decrease in tape adhesion. The lubricant content in the heat-fusible resin layer 3 of the packaging material 1 (i.e., before wiping with an organic solvent-impregnated cloth) is preferably set to 200 ppm to 9000 ppm.

[0019] Next, the exterior packaging material is stacked in a roll shape so that 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 so that they are in contact with each other, the lubricant in the heat-fusible resin layer is transferred to the surface of the heat-resistant resin layer.

[0020] Next, the exterior material 1 is pulled out from the roll, and the pulled-out exterior material 1 is molded to obtain an exterior case 10 for an electricity storage device. Because the lubricant is present on the surface of the heat-resistant resin layer due to the transfer, molding is carried out in a good state (the molded body is free of molding defects such as pinholes and cracks). Examples of the molding method include deep drawing, stretch molding, and embossing.

[0021] Next, a step is performed in which the lubricant is removed from the surface of the heat-resistant resin layer (outer layer) 2 of the electricity storage device outer case 10 using an organic solvent. In the above embodiment, a wiping step is performed as the step of removing the lubricant using an organic solvent.

[0022] That is, the surface of the heat-resistant resin layer (outer layer) 2 of the outer case 10 for a power storage device is wiped with a cloth impregnated with an organic solvent (wiping step). By wiping the surface of the outer layer with a cloth impregnated with an organic solvent in this manner, the lubricant on the surface of the outer layer can be removed and the wettability of the surface can be improved, thereby significantly improving the tape adhesion on the surface 2a of the outer layer. By wiping with the cloth impregnated with an organic solvent, the lubricant on the surface of the outer layer is removed, and the amount of lubricant on the outer surface 2a of the outer layer 2 is reduced to 0.01 μg / cm. 2 In particular, the amount of lubricant on the outer surface 2a of the outer layer 2 is set to less than 0.008 μg / cm 2 It is preferable to keep it below 0.006 μg / cm 2 It is particularly preferable that the wet tension of the outer surface 2a of the outer layer 2 be 30 mN / m or more. In addition, by wiping the surface of the outer layer 2 with a cloth impregnated with an organic solvent, the wet tension of the outer surface 2a of the outer layer 2 can be made 30 mN / m or more. In particular, it is preferable that the wet tension of the outer surface 2a of the outer layer 2 be 35 mN / m or more, and it is particularly preferable that the wet tension be 38 mN / m or more.

[0023] The organic solvent is not particularly limited, but examples thereof include alcohols, butyl acetate, ethyl acetate, etc. The alcohol is not particularly limited, but examples thereof include methanol, ethanol, isopropyl alcohol, etc. Among these, it is preferable to use alcohols as the organic solvent. The fabric is not particularly limited as long as it is in the form of a cloth and can contain an organic solvent, and examples thereof include woven fabrics, nonwoven fabrics, knitted fabrics, etc.

[0024] In the present invention, the outer layer 2 is formed of a heat-resistant resin layer. The heat-resistant resin constituting the heat-resistant resin layer 2 is a heat-resistant resin that does not melt at the heat-sealing temperature when the packaging material 1 is heat-sealed. As the heat-resistant resin, a heat-resistant resin having a melting point 10°C or more higher than the melting point of the heat-fusible resin constituting the heat-fusible resin layer 3 is preferably used, and a heat-resistant resin having a melting point 20°C or more higher than the melting point of the heat-fusible resin is particularly preferably used.

[0025] The heat-resistant resin layer (outer layer) 2 is a member that mainly plays a role in ensuring good formability, that is, it mainly plays a role in preventing breakage due to necking of the aluminum foil during forming.

[0026] The heat-resistant resin layer (outer layer) 2 is not particularly limited, but examples thereof include stretched polyamide films such as stretched nylon films, stretched polyester films, etc. Among these, the heat-resistant resin layer 2 is preferably a biaxially stretched polyamide film such as biaxially stretched nylon film, a biaxially stretched polybutylene terephthalate (PBT) film, a biaxially stretched polyethylene terephthalate (PET) film, or a biaxially stretched polyethylene naphthalate (PEN) film, all of which have a hot water shrinkage rate of 0.1% to 12%. Furthermore, the heat-resistant resin layer 2 is preferably a biaxially stretched heat-resistant resin film stretched by simultaneous biaxial stretching. The nylon is not particularly limited, but examples thereof include nylon 6, nylon 6,6, and MXD nylon. The heat-resistant resin film layer 2 may be formed as a single layer (a single stretched film), or may be formed as a multilayer consisting of, for example, a stretched polyester film / stretched polyamide film (such as a multilayer consisting of a stretched PET film / stretched nylon film).

[0027] The thickness of the heat-resistant resin layer 2 is preferably 7 μm to 50 μm. By setting the thickness to be equal to or greater than the above-mentioned preferable lower limit, sufficient strength as an exterior packaging material can be ensured, and by setting the thickness to be equal to or less than the above-mentioned preferable upper limit, stress during stretch forming or draw forming can be reduced, thereby improving formability.

[0028] In the present invention, the metal foil layer 4 serves to impart gas barrier properties to the packaging material 1, preventing the intrusion 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, and Ti foil, with aluminum foil being commonly used. The thickness of the metal foil layer 4 is preferably 10 μm to 120 μm. A thickness of 10 μm or more can prevent the occurrence of pinholes during rolling in the production of the metal foil, while a thickness of 120 μm or less can reduce stress during forming, such as stretch forming and drawing, thereby improving formability. Of these, a thickness of 10 μm to 80 μm is particularly preferred for the metal foil layer 4.

[0029] 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, corrosion of the metal foil surface due to the contents (such as the electrolyte of a battery) can be sufficiently prevented. For example, the chemical conversion treatment is performed on the metal foil by the following treatment. That is, for example, the surface of the metal foil that has been subjected to a degreasing treatment is 1) phosphoric acid, Chromic acid, and at least one compound selected from the group consisting of metal salts of fluoride and non-metal salts of fluoride. 2) phosphoric acid, at least one resin selected from the group consisting of acrylic resins, chitosan derivative resins, and phenolic resins; and 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; and at least one compound selected from the group consisting of metal salts of fluoride and non-metal salts of fluoride. The chemical conversion treatment is carried out by applying an aqueous solution of any one of the above 1) to 3) and then drying it.

[0030] The chemical conversion coating has a chromium deposition amount (per side) of 0.1 mg / m 2 ~50mg / m 2 is preferred, and 2 mg / m 2 ~20mg / m 2 is preferred.

[0031] The heat-sealable resin layer (inner layer) 3 provides excellent chemical resistance to highly corrosive electrolytes used in lithium ion secondary batteries and the like, and also plays a role in imparting heat sealability to the exterior packaging material.

[0032] The resin constituting the heat-sealable resin layer 3 is not particularly limited, but examples thereof include polyethylene, polypropylene, ionomer, ethylene ethyl acrylate (EEA), ethylene methyl acrylate (EAA), ethylene methyl methacrylate resin (EMMA), ethylene-vinyl acetate copolymer resin (EVA), maleic anhydride-modified polypropylene, and maleic anhydride-modified polyethylene.

[0033] The thickness of the heat-sealable resin layer 3 is preferably set to 10 μm to 100 μm. By setting the thickness to 10 μm or more, sufficient heat seal strength can be ensured, and by setting the thickness to 100 μm or less, it contributes to thinning and weight reduction. In particular, the thickness of the heat-sealable resin layer 3 is more preferably set to 10 μm to 80 μm. The heat-sealable resin layer 3 is preferably formed of a heat-sealable resin unstretched film layer, and the heat-sealable resin layer 3 may be a single layer or multiple layers.

[0034] In the present invention, the lubricant is not particularly limited, but examples thereof include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, aromatic bisamides, etc. These lubricants are easily mobile in polyolefins, particularly polypropylene, and are suitable for exuding and transferring the lubricant.

[0035] The saturated fatty acid amides are not particularly limited, but examples thereof include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, etc. The unsaturated fatty acid amides are not particularly limited, but examples thereof include oleic acid amide, erucic acid amide, etc.

[0036] The substituted amides are not particularly limited, but examples thereof include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, etc. Furthermore, the methylol amides are not particularly limited, but examples thereof include methylol stearic acid amide, etc.

[0037] The saturated fatty acid bisamide is not particularly limited, but examples thereof include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene 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.

[0038] The unsaturated fatty acid bisamide is not particularly limited, but examples thereof include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl sebacic acid amide, and N,N'-dioleyl adipic acid amide.

[0039] The fatty acid ester amide is not particularly limited, but examples thereof include stearamidoethyl stearate, etc. The aromatic bisamide is not particularly limited, but examples thereof include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, N,N'-cystearyl isophthalic acid amide, etc. [Example]

[0040] Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.

[0041] Example 1 A chemical conversion coating was formed by applying a chemical conversion treatment solution consisting of phosphoric acid, polyacrylic acid (acrylic resin), a chromium (III) salt compound, water, and alcohol to both sides of a 40 μm thick aluminum foil 4 and then drying at 180° C. The chromium deposition amount of this chemical conversion coating was 10 mg / m per side. 2 It was.

[0042] Next, a biaxially oriented 6 nylon film 2 having a thickness of 25 μm was dry laminated (attached) to one surface of the chemically treated aluminum foil 4 via a two-component curing urethane adhesive (thickness: 2 μm) 5 .

[0043] Next, a first unstretched film having a thickness of 4.5 μm containing an ethylene-propylene random copolymer, 1000 ppm of behenic acid amide, and 3000 ppm of silica particles (antiblocking agent), a second unstretched film having a thickness of 21 μm containing an ethylene-propylene block copolymer and 1000 ppm of erucic acid amide, and a first unstretched film having a thickness of 4.5 μm containing an ethylene-propylene random copolymer, 1000 ppm of behenic acid amide, and 3000 ppm of silica particles (antiblocking agent) were prepared. The three layers were co-extruded using a T-die so as to laminate them in this order, to obtain a sealant film (inner layer) 3, and then the first unstretched film surface of the sealant film 3 was superimposed on the other surface of the dry-laminated aluminum foil 4 via an olefin-based adhesive (thickness: 2 μm) 6, and dry-laminated by being sandwiched and pressed between a rubber nip roll and a laminating roll heated to 100°C, and then aged (heated) at 40°C for 10 days to obtain an exterior material 1 for an electricity storage device having the configuration shown in Figure 1.

[0044] The obtained exterior material was cut into a sheet measuring 200 mm long x 200 mm wide. This sheet was then used in a press molding machine to produce a molded article measuring 150 mm long x 150 mm wide x 5 mm deep (press speed: 20 spm, wrinkle suppression pressure: 1.60 MPa). The surface of the outer layer 2 of the obtained molded article was wiped with an ethanol-impregnated cloth (Bencotto (product name) manufactured by Asahi Kasei Corporation), to obtain an exterior case 10 for an electricity storage device as shown in FIG. 2.

[0045] <Example 2> An outer case 10 for a power storage device shown in FIG. 2 was obtained in the same manner as in Example 1, except that the sealant film 3 used was a sealant film obtained by co-extrusion using a T-die to laminate three layers in this order: a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 6000 ppm of behenamide, and 3000 ppm of silica particles (antiblocking agent); a second unstretched film having a thickness of 21 μm and containing an ethylene-propylene block copolymer and 6000 ppm of erucamide; and a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 6000 ppm of behenamide, and 3000 ppm of silica particles (antiblocking agent).

[0046] Example 3 An outer case 10 for a power storage device shown in FIG. 2 was obtained in the same manner as in Example 1, except that the sealant film 3 used was a sealant film obtained by co-extrusion using a T-die to laminate three layers in this order: a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 500 ppm of behenamide, and 3000 ppm of silica particles (antiblocking agent); a second unstretched film having a thickness of 21 μm and containing an ethylene-propylene block copolymer and 500 ppm of erucamide; and a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 500 ppm of behenamide, and 3000 ppm of silica particles (antiblocking agent).

[0047] Example 4 An outer case 10 for a power storage device shown in FIG. 2 was obtained in the same manner as in Example 1, except that the sealant film 3 used was a sealant film obtained by co-extrusion using a T-die so that three layers were laminated in this order: a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 7000 ppm of behenamide, and 3000 ppm of silica particles (antiblocking agent); a second unstretched film having a thickness of 21 μm and containing an ethylene-propylene block copolymer and 5000 ppm of erucamide; and a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 7000 ppm of behenamide, and 3000 ppm of silica particles (antiblocking agent).

[0048] <Example 5> An outer case 10 for a power storage device shown in FIG. 2 was obtained in the same manner as in Example 1, except that an ethyl acetate-impregnated nonwoven fabric was used instead of the ethanol-impregnated nonwoven fabric during the wiping operation.

[0049] <Comparative Example 1> An outer case for an electricity storage device was obtained in the same manner as in Example 1, except that the molded article was not subjected to wiping with an ethanol-impregnated cloth.

[0050] <Comparative Example 2> An outer case for a power storage device was obtained in the same manner as in Example 1, except that a solvent-unimpregnated dry cloth (Bencott (product name) manufactured by Asahi Kasei Corporation) was used instead of the ethanol-impregnated cloth during the wiping operation.

[0051] <Comparative Example 3> An outer case for an electricity storage device was obtained in the same manner as in Example 1, except that the sealant film 3 used was a sealant film obtained by co-extrusion using a T-die so that three layers were laminated in this order: a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 100 ppm of behenamide, and 3000 ppm of silica particles (antiblocking agent), a second unstretched film having a thickness of 21 μm and containing an ethylene-propylene block copolymer and 100 ppm of erucamide, and a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 100 ppm of behenamide, and 3000 ppm of silica particles (antiblocking agent).

[0052] <Comparative Example 4> An outer case for an electricity storage device was obtained in the same manner as in Example 1, except that the sealant film 3 used was a sealant film obtained by co-extrusion using a T-die so that three layers were laminated in this order: a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 10,000 ppm of behenic acid amide, and 3,000 ppm of silica particles (antiblocking agent); a second unstretched film having a thickness of 21 μm and containing an ethylene-propylene block copolymer and 10,000 ppm of erucic acid amide; and a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 10,000 ppm of behenic acid amide, and 3,000 ppm of silica particles (antiblocking agent).

[0053] <Comparative Example 5> As the sealant film 3, a sealant film obtained by co-extrusion using a T-die to laminate three layers in this order: a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 7000 ppm of behenic acid amide, and 3000 ppm of silica particles (antiblocking agent); a second unstretched film having a thickness of 21 μm and containing an ethylene-propylene block copolymer and 7000 ppm of erucic acid amide; and a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 7000 ppm of behenic acid amide, and 3000 ppm of silica particles (antiblocking agent) was used; and an outer case for an electricity storage device was obtained in the same manner as in Example 1, except that the aging temperature was set to 50°C.

[0054] <Comparative Example 6> An outer case for a storage battery device was obtained in the same manner as in Example 1, except that the sealant film 3 used was a sealant film obtained by co-extrusion using a T-die to laminate three layers in this order: a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 200 ppm of ethylene bisoleic acid amide, and 3000 ppm of silica particles (antiblocking agent); a second unstretched film having a thickness of 21 μm and containing an ethylene-propylene block copolymer and 200 ppm of ethylene bisoleic acid amide; and a first unstretched film having a thickness of 4.5 μm and containing an ethylene-propylene random copolymer, 200 ppm of ethylene bisoleic acid amide, and 3000 ppm of silica particles (antiblocking agent).

[0055] [Table 1]

[0056] For the outer cases for electricity storage devices obtained as described above, the amounts of lubricant present on the surfaces of the outer layer and the inner layer were evaluated, the wetting tension (wetting index) of the surfaces of the outer layer was measured, and the formability, appearance, and tape adhesion were evaluated.

[0057] <Method for evaluating the amount of lubricant present on the surface of the outer layer> Two rectangular test pieces measuring 100 mm long x 100 mm wide were cut out from each exterior case 10 for an electricity storage device, and then these two test pieces were overlapped with the outer layer facing inward, and the peripheral edges of the surfaces of the outer layers were heat-sealed together at a heat-sealing temperature of 250°C with a seal width of 5 mm to produce a bag. 1 mL of acetone was injected into the internal space of this bag using a syringe, and the bag was left in contact with the inner surface of the bag for 3 minutes, after which the acetone was removed from the bag. The amount of components contained in this removed liquid was measured and analyzed using a gas chromatograph to determine the amount of lubricant (μg / cm) present on the surface (outer surface) 2a of the outer layer 2 of the exterior case 10. 2 ) was sought.

[0058] <Method for evaluating the amount of lubricant present on the surface of the inner layer> Two rectangular test pieces measuring 100 mm long x 100 mm wide were cut out from each exterior case 10 for an electricity storage device, and then these two test pieces were overlapped with the inner layer facing inward, and the peripheral edges of the surfaces of the inner layers were heat-sealed at a heat-sealing temperature of 250°C with a seal width of 5 mm to produce a bag. 1 mL of acetone was injected into the internal space of this bag using a syringe, and the bag was left in contact with the inner surface of the bag for 3 minutes, after which the acetone was removed from the bag. The amount of components contained in this removed liquid was measured and analyzed using a gas chromatograph to determine the amount of lubricant (μg / cm) present on the surface (outer surface) 3a of the inner layer 3 of the exterior case 10. 2 ) was sought.

[0059] <Method for measuring wetting tension> The wettability index (surface tension) of the surface 2a of the outer layer of each outer case for an electricity storage device was measured in accordance with JIS K6768-1999.

[0060] <Formability evaluation method> Exterior material 1 was molded using a press molding machine to obtain a molded product measuring 150 mm in length, 150 mm in width, and 5 mm in depth. The molded product was then visually inspected, and those that had no cracks or pinholes were marked with an "O" and those that had cracks or pinholes were marked with an "X".

[0061] <Appearance evaluation method> The surface of the obtained outer case 10 was visually inspected, and those in which white powder had appeared on the surface of the inner layer were marked with "X", and those in which white powder had not appeared on the surface of the inner layer were marked with "O".

[0062] <Tape adhesion evaluation method> A rectangular test piece measuring 145 mm long x 145 mm wide was taken from the largest surface of each exterior case for an electric storage device. A 5 mm wide x 100 mm long adhesive tape was attached to the surface of the outer layer 2 of the test piece, and then a 2 kg roller was rolled back and forth over the adhesive tape five times while applying a load to the adhesive tape. The test piece was then left to stand for 1 hour in a room at 25°C. Next, in accordance with JIS K6854-3 (1999), the test piece was clamped and fixed with one chuck using a Shimadzu Strograph AGS-5kNX, and the adhesive tape was clamped and fixed with the other chuck, and the 180° peel strength was measured. Tape adhesion was evaluated from the peel strength based on the following criteria. (Judgment criteria) "◎": Peel strength is 6N / 5mm or more (passed) "○": Peel strength is 5N / 5mm or more and less than 6N / 5mm (passed) "X": Peel strength is less than 5N / 5mm.

[0063] As is clear from the table, the outer cases of Examples 1 to 5 of the present invention were well molded and had good tape adhesion. In contrast, Comparative Examples 1 to 6, which fall outside the range specified in the present invention, were evaluated as poor in at least one of "moldability," "appearance," and "tape adhesion." Note that Comparative Examples 3 and 6 were evaluated as having poor moldability, so tape adhesion was not evaluated. [Industrial Applicability]

[0064] Specific examples of the outer case (molded case) for an electricity storage device according to the present invention include: - Energy storage devices such as lithium secondary batteries (lithium ion batteries, lithium polymer batteries, etc.) Lithium-ion capacitor Electric double layer capacitor ·All-solid-state battery It is used as an exterior case for various types of electricity storage devices such as: [Explanation of symbols]

[0065] 1...Exterior material 2...Heat-resistant resin layer (outer layer) 2a...Outer surface of heat-resistant resin layer 3…Thermofusible resin layer (inner layer) 4…Metal foil layer 10...Outer case (molded case)

Claims

[Claim 1] A method for manufacturing a battery that is exterior-packaged with an exterior material and fixed by affixing adhesive tape to the outer surface of the exterior material, comprising: a process of obtaining an exterior case for an electricity storage device by using a roll body in which an exterior material including 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 disposed between the two layers is stacked in a roll shape in such a manner that the heat-fusible resin layer and the heat-resistant resin layer are in contact with each other, and pulling out the exterior material from the roll body and molding the pulled-out exterior material; removing the lubricant present on the surface of the outer layer of the outer case for the electricity storage device with an organic solvent, the heat-fusible resin layer has a lubricant content of 200 ppm to 8000 ppm; the amount of lubricant on the outer surface of the heat-fusible resin layer is 0.10 μg / cm 2 to 1.0 μg / cm 2 ; the heat-resistant resin layer is formed of a biaxially stretched film, the amount of lubricant on the outer surface of the heat-resistant resin layer after removal of the lubricant is 0.003 μg / cm 2 to 0.008 μg / cm 2 ; A method for manufacturing a battery, wherein the outer surface of the heat-resistant resin layer has a wet tension of 30 mN / m to 59 mN / m after removal of the lubricant.

Images