Patent ID: 6805991
Filing Date: 2004-10-19
Classification: H01M,Y02E,Y02P

Abstract:
A nonaqueous electrolyte secondary battery comprising a safety valve arranged on one end of a cylindrical outer packaging can holding an electrode element therein, the safety valve comprising a projecting portion projecting toward the electrode element and connected to a lead of the electrode element at the center of the safety valve, wherein:a plurality of linear thin portions are formed almost along at least two circumferences centering on the projecting portion; a small circle having a small diameter and a circle having a large diameter circle exist; a plurality of linear thin portions along the large diameter circle and a plurality of linear thin portions along the small diameter circle are formed almost equal portion to each other centering on the projection portion; and a thin portion extending in a radial direction is formed across end portions of the linear thin portions adjacent to each other.