Assembling method for battery outer case for receiving a flat battery pack joined by seam-rolling

1. 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.

2. The assembly method for a battery outer case as claimed in claim 1 , wherein the reinforcement portion comprises a reinforcement bead is formed at a location adjacent to each of said notched holes in said metal container main body so as to provide high rigidity.

3. The assembly method for a battery outer case as claimed in claim 1 , wherein the reinforcement portion comprises a turned back portion formed around each of said notched holes so as to provide high rigidity.

4. The assembly method for a battery outer case as claimed in claim 1 , wherein said notched holes are in the form of U shapes conforming to the configurations of the terminal insulation resin covers that cover the terminal.

5. The assembly method for a battery outer case as claimed in claim 1 , wherein said notched holes are in the form of U shapes conforming to the configurations of the terminal.

6. The assembly method for a battery outer case as claimed in claim 3 , wherein said turned back portion forms an upright rib constructed in such a manner that the rib is turned back in a direction to protrude outside of the container to form a U-shaped configuration.

7. The assembly method for a battery outer case as claimed in claim 6 , wherein said metal container main body and said metal lid have at least their inner surfaces coated with insulating layers respectively, so that the inner surface side of the container is exposed to the surface of said upright ribs.