| 摘要 |
PROBLEM TO BE SOLVED: To fit a lid to a designated position of an opening when sealing it, and to prevent a sealing defect, by a method in which a metal sheet constituting the lid of a battery forms a recessed step to fit at least a part of its thickness, and the lid fitted in the recessed step is welded to a battery can to seal it. SOLUTION: A recessed step 5 having a thinly formed space matching the size of a lid 3 is formed on the inner surface of the upper end of an opening 2 at the upper end of a battery can 1, and the lid 3 is fitted in the recessed step 5 from the upper part to hold it. Accordingly, the lid 3 is held at a fixed position of the upper part of the battery can 1, and a contact surface can be always made constant even if the lid 3 is mounted onto the battery can 1 by an automated assembling device or the like. As a result, when welding it with a laser 4, welding spots are on the same plane, focuses to the welding spots can be accurately held and they can be reliably welded. Thereby, the lid 3 can be prevented from being deformed by heat at the time of welding and causing a sealing defect of the welded spot. |
