| 摘要 |
PROBLEM TO BE SOLVED: To perform the welding from over a lid, and perform the positioning with the simple working of part by forming an inner peripheral edge of an opening part of a case main body with a hole side taper, which is opened out, and forming the periphery of a lid with an axis side taper. SOLUTION: An axis side taper 22, which is formed in the periphery of a lid 2, is fitted in a hole side taper 22, which is formed so as to be opened out in the inner peripheral edge of an opening part of a case main body 1. In this fitting condition, the main body 1 and the lid 2 are welded to each other from over the lid 2 for airtight connection. With this structure, other welding to the lid such as a welding of a closure 4 to an electrolyte filling port 3 is performed from the same direction so as to improve the workability, and the working is facilitated by a stage difference provided in the opening part of the main body 1, and the cost is lowered. Sufficient thickness of the lid 2 can be secured independently of the working cost of the main body 1 side. This structure is especially effective for square battery, in which it is hard to air-tightly connect the main body 1 and the lid 2 to each other, or lithium secondary battery, in which sealing property of the case is important. |
