Patent ID: 6866961
Filing Date: 2005-03-15
Classification: H01M,Y02E,Y02P,Y02T,Y10T

Abstract:
1. A lithium secondary battery comprising: an internal electrode formed by winding a positive electrode and a negative electrode on an outer peripheral wall of a hollow cylindrical winding core; a cylindrical battery case containing the internal electrode body inside with both ends thereof being open; nonaqueous electrolyte solution contained in said case and contacting said positive electrode and said negative electrode; and electrode caps having battery caps, internal terminals, and external terminals, said battery caps sealing said internal electrode body at both open ends of the battery case, at least one of said battery caps having a pressure release hole in a position corresponding with a center axis of said winding core, wherein a pressure release valve is disposed on an internal peripheral wall of said pressure release hole or at the end of said pressure release hole, said pressure release valve comprising an elastic body, a metal foil and a spacer, said elastic body and said metal foil being brought into pressure contact with said spacer to seal said battery case, and wherein stress applied to said elastic body is not less than 980 kPa and not more than a force at which said elastic body maintains elasticity of not less than 95%.