Patent ID: 6946221

Claim:
A method for manufacturing a prismatic battery case, comprising: a first step for molding an intermediate cup body by impact molding a pellet, wherein said pellet has a shape that, in a plan view, corresponds to an outline of a cross sectional shape of the prismatic battery case; and a second step for molding a prismatic battery case with a cross section of a substantially rectangular shape by DI processing said intermediate cup body, the DI processing conducting drawing and ironing continuously in one action said intermediate cup body having a bottom face, said intermediate cup being molded by impact molding said pellet using a punch having a jagged surface along a front-end surface, said jagged surface being perpendicular to an axis line of the punch, the punch being adapted for forming a jagged surface throughout said bottom face of said intermediate cup so that the punch and pellet maintain a predetermined positional relationship during said first step.