METHOD FOR WELDING PLURAL ELECTRODE TAB AND ELECTRODE LEAD OF SECONDARY BATTERY AND SECONDARY BATTERY USING THE SAME METHOD FOR INSPECTING POOR WELDING OF SECONDARY BATTERY

摘要

The present invention relates to a welding method of multiple electrode tabs and an electrode lead of a secondary battery having an electrode assembly. The welding method comprises: (a) a step of overlapping the electrode tabs extended from a plurality of electrode plates for forming the electrode assembly upwards and downwards; (b) a step of locating the electrode lead on the upper or lower side of the electrode tabs to be overlapped with a part of the overlapped electrode tabs; and (c) a step of forming a welding surface by welding the portion wherein the electrode tabs and the electrode lead are overlapped by using a welding device. In the (c) step, the length of the welding surface is 0.4-0.7 mm inclusive. Accordingly, a welding failure due to the weak welding between the electrode tabs and the electrode lead and a short circuit of the electrode tabs by the strong welding can be prevented.