| 摘要 |
<P>PROBLEM TO BE SOLVED: To ensure the pressure tightness of a battery case by allowing to process the R section with a curvature radius as small as possible so that wall thickness reduction does not arise even when a ring-like groove is processed on the low-profile battery case. Ž<P>SOLUTION: A ring-like groove 12 is molded by fixing a case body 10 on a jig, pressing the case body 10 in the axial direction with a depressing mold 13 that is fitted to an opening 11 of the case body 10, and then pressing a groove processing roll 14 from the outer peripheral side of the case while rotating the case body 10. Thereafter, the case body 10 is placed into a dice 15 having a surface holding the shape of the ring-like groove 12 on the case body 10 and surfaces 18, 19 that form a flat portion 16 and R section 17 continuous with the flat portion 16 at the upper side of the ring-like groove 12, and a punch 23 is pressed into the dice 15 from the opening 11 of the case body 10. The flat portion 16 and R section 17 are molded along the shape of the dice 15 in such a manner. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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