Patent ID: 7611797
Filing Date: 2009-11-03
Classification: H01M,Y02E,Y02P

Abstract:
1. A lithium secondary battery comprising: a can made of a conductive metal in which an electrode unit having a positive electrode plate and a negative electrode plate with a separator interposed therebetween is housed with an electrolytic solution, an outer bottom surface of the can serving as a first terminal electrically connected to one of the positive electrode plate or the negative electrode plate, and an upper opening of the can that is sealed by a cap assembly and has a second terminal electrically connected to the other one of the positive electrode plate or the negative electrode plate; a safety vent formed in the bottom surface of the can; a bottom plate welded to the outer bottom surface of the can and positioned to protect the safety vent; a safety device; and a lead unit that electrically connects the first and second terminals through the safety device, the lead unit comprising a lead plate having one end directly welded to the outer bottom surface of the can and another end directly connected to the safety device so that the can is electrically connected to the safety device, wherein the bottom plate includes a weld portion welded to the outer bottom surface of the can, and an accommodating portion accommodating the one end of the lead plate between the accommodating portion and the outer bottom surface of the can and directly contacting the one end of the lead plate, and wherein the accommodating portion extends from the weld portion in a bent manner such that the lead plate fits between the outer bottom surface and the accommodating portion.