FLAT SQUARE BATTERY

摘要

A power generation element is stored in an inner space formed by combining a battery case ( 2 ) and a seal case ( 3 ) formed as a half-shell body with a rectangular plane shape such that the individual openings are placed opposing to each other with a gasket ( 4 ) interposed therebetween, and the gasket ( 4 ) is pressed between the open end of the battery case ( 2 ) and a step ( 35 ) of the seal case ( 3 ) for sealing during caulking. Because recesses ( 36 ) are formed on the individual peripheral edges of a bottom surface ( 31 ) of the seal case ( 3 ), the strength of straight parts of a seal-case side-peripheral surface ( 32 ) of the seal case ( 3 ) increases against a seal pressure during caulking, and a decrease of seal capability caused by the straight parts bulging toward the outside during sealing is prevented.