Patent ID: 8999564
Filing Date: 2015-04-07
Classification: H01M,Y02E

Abstract:
1. A secondary battery comprising: an electrode assembly comprising a first plate, a second plate, and a separator disposed between the first and second plates; a battery case accommodating the electrode assembly and an electrolyte, the battery case having an opening at one side; a cap assembly sealing the opening of the battery case, the cap assembly including an upper cap that is electrically coupled to the electrode assembly, the battery case including a crimping part having an outermost tip bent towards the cap assembly; and a gasket disposed between an outermost edge of the cap assembly and an internal surface of the battery case, the crimping part being disposed on the gasket, a ratio of a second thickness of the gasket to a first thickness of the gasket being greater than 1.8 and less than 4.8, the first thickness being a length between the internal surface of the battery case and the outermost edge of the cap assembly, the second thickness being a length between the internal surface of the battery case and the outermost tip of the crimping part, an entire surface of the edge portion of the upper cap, which faces the opening and is covered by the gasket, directly contacting the gasket.