A battery pack is provided. The battery pack includes: a generator device having a battery element disposed on a flexible covering material folded to cover the battery element, wherein three sides of the flexible covering material around the battery element are sealed; a rigid covering material for covering the generator device, having an opening and being bonded to the flexible covering material of the generator device; and a cover fitted into the opening of the rigid covering material, wherein the rigid covering material has a three-layer structure having an outer packaging layer, a metal layer, and a heat-bonding layer which are stacked on one another, and the heat-bonding layer is one selected from an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid copolymer, an ethyl acrylate copolymer, a methyl acrylate copolymer, a methacrylic acid copolymer, a methyl methacrylate copolymer, polyacrylonitrile, an ethylene vinyl alcohol resin, a polyamide resin, a polyester resin, acid-modified polypropylene, or an ionomer.
1. A battery pack comprising:
a battery element;
a generator device having said battery element disposed on a flexible covering material, said flexible covering material being folded to cover said battery element, wherein three sides of said flexible covering material around said battery element are sealed;
a rigid covering material for covering said generator device, said rigid covering material having an opening and being bonded to said flexible covering material of said generator device; and
a cover fitted into the opening of said rigid covering material,
wherein said rigid covering material has a four-layer structure having an outer packaging layer, a metal layer, an inner packaging layer, and a heat-bonding layer which are stacked on one another,
wherein said inner packaging layer is bonded to said cover, and
wherein said heat-bonding layer is at least one material selected from the group consisting of an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid copolymer, an ethyl acrylate copolymer, a methyl acrylate copolymer, a methacrylic acid copolymer, a methyl methacrylate copolymer, polyacrylonitrile, an ethylene vinyl alcohol resin, a polyamide resin, a polyester resin, acid-modified polypropylene, and an ionomer.
2. The battery pack according to claim 1 ,
wherein said flexible covering material has a three-layer structure having an outer packaging layer, a metal layer, and an inner packaging layer which are stacked on one another, and
wherein said outer packaging layer in said flexible covering material is bonded to said heat-bonding layer in said rigid covering material.
3. The battery pack according to claim 1 , wherein said outer packaging layer in said rigid covering material includes a material selected from the group consisting of a polyolefin resin, a polyamide resin, a polyimide resin, and polyester.
4. The battery pack according to claim 1 , wherein said inner packaging layer in said rigid covering material is a cast polyolefin resin or an ionomer.
5. The battery pack according to claim 1 ,
wherein said metal layer in said rigid covering material is formed of a hard metal, and
wherein said hard metal is hard aluminum, stainless steel, titanium, copper, or iron plated with tin, zinc, or nickel.
6. The battery pack according to claim 5 , wherein said hard metal has a thickness ranging from 50 to 100 μm.
7. The battery pack according to claim 5 , wherein said hard aluminum is 3003H18, 3004H18, or 1N30H18.
8. The battery pack according to claim 5 , wherein said stainless steel is austenite.
9. The battery pack according to claim 1 , wherein the ends of said rigid covering material are joined on one plane or one side of said generator device so that said ends do not overlap, and a label is put on said rigid covering material so that the label covers the joint of the ends of said rigid covering material.
10. The battery pack according to claim 1 , wherein the heat-bonding layer has a melting point lower than that of the inner packaging layer.
11. The battery pack according to claim 1 , wherein the inner packaging layer has a thickness ranging from 25 to 35 μm.