| 摘要 |
PURPOSE: To provide a welding method of a sealed vessel of a square battery by which welding failure based on relative displacement of a cover plate to a square case caused by welding can be reduced. CONSTITUTION: A cover plate 2 is fitted in an opening of a square case 1, and in a condition where the outer peripheral edge of the cover plate 2 is butted against the opening edge of the square case 1, these both edges 3 are welded together by a laser, and a sealed vessel is formed. In first constitution, after three or more places in the whole circumference to be welded are welded for temporary fastening, the whole circumference is regularly welded, and since at least one of a temporary fastening place 4 is set in a side part different from the other temporary fastening place 4, the cover plate 2 inclines by physical influence such as melting of a prescribed part of the cover plate 2 at regularly welding time, and parallelism is deteriorated, and the occurrence of welding failure particularly caused thereby can be prevented. |
