Patent ID: 8747490

Claim:
An assembling method for a battery outer case comprising the steps of: molding a metal container main body including a body portion of a polygonal cylindrical configuration and a plate portion which closes an end of the body portion, said body portion having notched holes, each notched hole including a pair of side edge portions that extend linearly and in parallel from the open end portion of the body portion toward end corners of the notched hole near the plate portion, an end edge portion connected between corresponding ends of the side edge portions, and reinforcement portions, so as to form said notched holes having peripheral reinforcement portions, the reinforcement portions are more rigid than remaining portions of said body portion of said metal container main body and are formed beforehand in said body portion for exposing terminals connected to a flat battery pack; receiving said flat battery pack in said metal container main body while fitting said terminals into said notched holes; covering said metal container main body with a metal lid; and superposing an open end portion of said body portion of said metal container main body divided by the notched holes and an end portion of said metal lid with each other thereby to join them to each other by pressing a seam roll against said respective end portions from a side thereof.