MANUFACTURING METHOD OF RECTANGULAR BATTERY CAN

A method of manufacturing a rectangular battery includes: ironing the blank thereby forming an interim cup including an interim bottom whose area is larger than a bottom plate of the rectangular battery can, an inclined wall tilting upwardly formed continuously from each longitudinal end of the interim bottom, a short side wall formed continuously from the inclined wall, and a long side wall formed continuously from a curved corner formed on each lateral end of the interim bottom; deforming the interim cup such that each boundary between the interim bottom and the inclined wall is displaced toward a longitudinal end of the bottom plate of the rectangular battery can, and a width of the interim bottom is adjusted to a width of the bottom plate of the rectangular battery can; and ironing the short side and long side walls to reduce thicknesses of the short side and long side walls.