Battery pack and method for welding cells

摘要

In a battery pack in which multiple battery cells are arranged in one or multiple rows in an electrically insulating case and an electrode of each battery cell is coupled to an electrode of another battery cell through a connecting metallic plate, the connecting metallic plate (3) made of copper is disposed on a positive electrode (6) of each battery cell (2) and on a negative electrode (7) of another battery cell to form a lap joint, and a weld (5) is formed in each of one predetermined position on the connecting metallic plate (3) above the positive electrode (6) and another predetermined position on the connecting metallic plate (3) above the negative electrode (7) by applying arc spot welding. The depth h of weld penetration in the weld (5) is greater than the thickness T1 of the connecting metallic plate (3) and smaller than the thickness T1 plus the thickness T2 of the positive electrode (6) or the negative electrode (7), that is, T1 < h ‰ (T1 + T2 x 4/5).