Patent ID: 8597823

Claim:
A battery comprising: a power generation element; and a case member having a housing space for housing the power generation element therein; wherein the case member includes: a first member forming an opening of the housing space; and a second member which closes the opening of the first member, wherein the first and second members are welded to each other at a welded portion formed in the first and second members, wherein at least one of the first and second members is formed with a metal receiving area in an inter-member path between the first and second members to extend from the welded portion to the housing space, the metal receiving area being configured to receive a part of molten metal generated during welding, wherein the first and second members are provided with a clearance portion in the inter-member path on the side from the metal receiving area to the housing space, the clearance portion being smaller than a clearance at the metal receiving area between the first and second members, and wherein the metal receiving area is formed along an entire circumference of the opening of the first member.