FLATTENED SQUARE TYPE BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a flattened square type battery having a construction to solve deterioration of sealability when a flattened battery is formed as a square type. SOLUTION: An electric generation element is housed in an internal space provided by combination of a battery case 2 formed as a square semi-shell type in a planar shape and an opening side of a sealing case 3 which are faced each other. The opening is sealed by compressing a gasket 4 above a stepped portion 35 of the sealing case 3 through caulking by which an opening end side of the battery case 2 is folded via the gasket 4. A side circumferential face 32 which rises to the stepped portion 35 from a bottom face 31 of the sealing case 3 and the stepped portion 35 are formed to be thick in wall thickness, by which strength is increased, deterioration of sealability caused by buckling of a straight-line portion of the side circumferential face when sealing is prevented, and the flattened square type battery can be constituted.