Patent ID: 6893773

Claim:
A flat prismatic battery comprising: a metal battery case formed as a polygonal half-shell body by rising a battery-case side-peripheral surface from a periphery of a polygonal bottom surface having corners rounded with a predetermined radius; and a metal seal case formed as a polygonal half-shell body by rising a seal-case side-peripheral surface having a shape and a dimension separated from an inner surface of said battery-case side-peripheral surface by a uniform interval from a periphery of a polygonal bottom surface having corners rounded with a predetermined radius, the side-peripheral surface being provided with a step at a position corresponding to a raised height of said battery-case side-peripheral surface, wherein a plurality of recesses protruding toward the inside of said seal case are provided at a predetermined interval on individual peripheral edges of the bottom surface of said seal case, an inner space formed by placing openings of said battery case and said seal case opposing to each other with a gasket interposed therebetween stores a power generation element, and said gasket is pressed and deformed between an open end of said battery case and the step of said seal case for sealing.