Battery and method for manufacturing the same

摘要

After accommodating an electrode group in a battery case having a substantially square transverse cross section, making an opening head of the battery case into a cylindrical shape through compression molding, an annular groove is formed by pressing a groove-forming roller sideways against a side surface of the opening head while rotating the battery case with a pressing force being kept applied to the battery case in an axial direction from the opening portion side, or alternatively pressing the groove-forming roller against the opening head from the side surface thereof and concurrently displacing the groove-forming roller in a direction toward the opening portion of the battery case while rotating the battery case. After having an annular supporting portion that bulges inward of the battery case support an opening-sealing member, the opening-sealing member is fixed through caulking by bending the opening end portion of the battery case inward, whereby a battery is manufactured.