| 摘要 |
PROBLEM TO BE SOLVED: To prevent the burst and the liquid leakage of a battery when performing excessive charge in a flat nonaqueous electrolyte secondary battery in which positive and negative electrode facing area is increased to improve a heavy-load property by improving the sealability of the battery. SOLUTION: In this flat nonaqueous electrolyte secondary battery, an electrode group including a positive electrode plate 3, a separator 8 and a negative electrode plate 4 and an nonaqueous electrolyte are contained in a positive electrode case 1 and a negative electrode case 5 which are fitted and sealed by caulking, the total of the positive and negative electrode facing area through a separator of the electrode group is made larger than an opening area of an insulating gasket 7 to improve the heavy-load property. The constitution of the sealing part is made so that the length of a part where the innermost circumferential end of the positive electrode case overlaps with the outermost periphery end of the negative electrode case is 0.05 mm or more and 0.45 mm or less in projection from above. COPYRIGHT: (C)2005,JPO&NCIPI |
