| 摘要 |
PURPOSE:To prevent the generation of minute cracks at a laser welded part by performing a lusterless electric nickel plating with a specific plating thickness and hardness there of at the welded part. CONSTITUTION:A battery case 1 and a cover 3, which are made of steel and on which lusterless electric nickel plating are performed, are used. In this nickel plating, a lust agent of an organic group or the like, which is conventionally used, is not added, but a pH buffer agent such as a lusterless plating solution consisting of boric acid and a nickel salt solution of higher concentration is used. Then, electrolytic precipitating conditions are controlled to perform the lusterless electric nickel plating so that hardness of plating layer is Hv=280 or less in Vickers hardness and its thickness is 2mum to 10mum. |
