External packaging material for battery device, nonaqueous electrolyte secondary battery using the same, and battery pack

Abstract

An external packaging material for covering a battery device is provided. The packaging material includes a laminated film having a laminated structure having two or more resin film layers stacked. In the external packaging material, the laminated structure has no metallic foil, and at least one layer in the resin film layers contains a moisture absorbing material.

The invention is claimed as follows: 
     
         1 . An external packaging material for covering a battery device, the packaging material comprising:
 a laminated film having a laminated structure having two or more resin film layers stacked,   wherein the laminated structure has no metallic foil, and   wherein at least one layer in the resin film layers contains a moisture absorbing material.   
     
     
         2 . The external packaging material according to  claim 1 , wherein the moisture absorbing material is contained in an inner layer other than an outermost layer in the resin film layers. 
     
     
         3 . The external packaging material according to  claim 1 , wherein the laminated structure further has a bonding agent layer or layers between the resin film layers, in which the bonding agent layer or at least one layer in the bonding agent layers contains the moisture absorbing material. 
     
     
         4 . An external packaging material for covering a battery device, the packaging material comprising:
 a laminated film having a laminated structure having two or more resin film layers stacked with a bonding agent layer or layers disposed in between, wherein the laminated structure has no metallic foil, and   wherein the bonding agent layer or at least one layer in the bonding agent layers contains a moisture absorbing material.   
     
     
         5 . The external packaging material according to  claim 4 , wherein the laminated structure has a plurality of bonding agent layers, in which the moisture absorbing material is contained in the inner layer or layers in the bonding agent layers. 
     
     
         6 . The external packaging material according to  claim 1 , wherein the moisture absorbing material is comprised of at least one inorganic compound selected from the group consisting of an oxide, a chloride, a sulfate, and a nitrate of sodium, potassium, magnesium, or calcium, at least one polyacrylate represented by —CH 2 —CH(COOM)-) n ,
 where M represents sodium, potassium, magnesium, or calcium, and n represents a natural number of 100 to 5,000, or a mixture thereof. 
 
     
     
         7 . The external packaging material according to  claim 6 , wherein the moisture absorbing material is added in an amount of 0.1% to 45%, based on the mass of the resin film layer or bonding agent layer containing the moisture absorbing material. 
     
     
         8 . The external packaging material according to  claim 1 , wherein an outermost layer in the resin film layers is formed of a film mainly composed of at least one resin selected from the group consisting of oriented nylon, oriented polyethylene terephthalate, oriented polyethylene naphthalate, oriented polybutylene terephthalate, oriented polybutylene naphthalate, oriented polypropylene, oriented polyethylene, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinylidene chloride-coated cellophane, polyamide, polyester, polyimide, polyphenylene ether, polysulfone, a fluororesin, polyvinyl alcohol, amorphous cycloolefin, a polyvinylidene chloride-coated resin, a polyvinyl alcohol-coated resin, a thin film ceramic-deposited or thin film ceramic-coated resin, and a resin obtained by adding a thermosetting resin to a layer silicate. 
     
     
         9 . The external packaging material according to  claim 1 , wherein
 an inner layer other than an outermost layer in the resin film layers is formed of a film or hot-melt layer mainly composed of at least one resin selected from the group consisting of casted polyethylene, casted polypropylene, a casted ethylene-vinyl acetate copolymer, a casted ethylene-acetic acid-vinyl alcohol copolymer, a casted ethylene-acrylic acid copolymer, a casted ethylene-ethyl acrylate copolymer, a casted ethylene-methyl acrylate copolymer, a casted ethylene-methacrylic acid copolymer, a casted ethylene-methyl methacrylate copolymer, a casted ionomer, casted polyacrylonitrile, casted polyethylene terephthalate, a fluororesin, polyvinylidene chloride, polyvinyl alcohol, amorphous cycloolefin, a polyvinylidene chloride-coated resin, a polyvinyl alcohol resin-coated resin, a thin film ceramic-deposited or thin film ceramic-coated resin, modified polypropylene, modified polyethylene, polystyrene, a carboxylic resin, and an ionomer.   
     
     
         10 . The external packaging material according to  claim 1 , wherein
 the film constituting at least one layer in the resin film layers has on a top or bottom surface thereof or both, at least one film selected from the group consisting of an aluminum deposited film, a carbon deposited film, a silicon oxide deposited film, an aluminum oxide deposited film, a polyvinylidene chloride coating film, and a layer silicate film.   
     
     
         11 . A nonaqueous electrolyte secondary battery comprising:
 a battery device composed of a positive electrode and a negative electrode which are stacked with a separator disposed in between and spirally wound; and   an external packaging material for covering the battery device, in which the external packaging material is sealed around the battery device so that electrode terminals of the positive electrode and the negative electrode are electrically introduced from the battery device,   wherein the external packaging material is composed of a laminated film having a laminated structure having two or more resin film layers stacked,   wherein the laminated structure has no metallic foil, and   wherein at least one layer in the resin film layers contains a moisture absorbing material.   
     
     
         12 . A nonaqueous electrolyte secondary battery comprising:
 a battery device composed of a positive electrode and a negative electrode which are stacked with a separator disposed in between and spirally wound; and   an external packaging material for covering the battery device, in which the external packaging material is sealed around the battery device so that electrode terminals of the positive electrode and the negative electrode are electrically introduced from the battery device,   wherein the external packaging material is composed of a laminated film having a laminated structure having two or more resin film layers stacked with a bonding agent layer in between,   wherein the laminated structure has no metallic foil, and   wherein the bonding agent layer or at least one layer in the bonding agent layers contains a moisture absorbing material.   
     
     
         13 . The nonaqueous electrolyte secondary battery according to  claim 11  wherein
 the whole of the interface at a sealed portion of the external packaging material and the electrode terminal has disposed thereon a resin film mainly composed of at least one member selected from the group consisting of maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, polyethylene containing a titanate coupling agent, polypropylene containing a titanate coupling agent, an ionomer, an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, an ethylene-vinyl acetate copolymer, casted polyethylene, casted polypropylene, a casted ethylene-vinyl acetate copolymer, a casted ethylene-acetic acid-vinyl alcohol copolymer, a casted ethylene-methyl acrylate copolymer, a casted ethylene-methyl methacrylate copolymer, casted polyacrylonitrile, and casted polyethylene terephthalate. 
 
     
     
         14 . The nonaqueous electrolyte secondary battery according to  claim 11 ,
 wherein the interface at a sealed portion of the external packaging material and the electrode terminal has no sealant film,   wherein an innermost layer in the resin film layers is formed of a film or hot-melt layer mainly composed of at least one resin selected from the group consisting of casted maleic anhydride-modified polyethylene, casted maleic anhydride-modified polypropylene, casted polyethylene containing a titanate coupling agent, casted polypropylene containing a titanate coupling agent, a casted ionomer, a casted ethylene-acrylic acid copolymer, and a casted ethylene-methacrylic acid copolymer, and   wherein the innermost layer is directly heat-bonded to the electrode terminal.   
     
     
         15 . The nonaqueous electrolyte secondary battery according to  claim 11  wherein the sealed portion of the external packaging material and the electrode terminal has no sealant film, and wherein the electrode terminal has a primer-processed surface. 
     
     
         16 . The nonaqueous electrolyte secondary battery according to  claim 11 , wherein the external packaging material has a space for containing the battery device. 
     
     
         17 . The nonaqueous electrolyte secondary battery according to  claim 16 ,
 wherein part of the sealed portion of the external packaging material formed around the battery device forms an electrode lead-out portion for sealing the external packaging material so that the electrode terminals are electrically introduced from the battery device, and   wherein the electrode lead-out portion has a sealed width ranging from 0.5 mm to 3.5 mm.   
     
     
         18 . The nonaqueous electrolyte secondary battery according to  claim 17 ,
 wherein the battery device has a rectangular plate shape, in which the electrode terminal extends from one side of the battery device and is sealed at the electrode lead-out portion of the external packaging material,   wherein the sealed portion of the external packaging material constitutes a rectangular frame form around the battery device, in which the electrode lead-out portion constitutes one side of the sealed portion,   wherein in the sealed portion constituting the rectangular frame form, the sealed portions constituting two sides substantially perpendicular to the electrode lead-out portion have a width equal to or smaller than the thickness of the battery device, and   wherein each of the side sealed portions forms a sidewall by bending once at an angle of 80° to 100° to the surface of the electrode lead-out portion.   
     
     
         19 . The nonaqueous electrolyte secondary battery according to  claim 11 , wherein at least one layer in the resin film layers constituting the external packaging material includes means for detecting leakage of the nonaqueous electrolytic solution.