Patent ID: 8088510

Claim:
A lithium secondary battery comprising an electrode group, a non-aqueous electrolyte and a battery case for housing said electrode group and said non-aqueous electrolyte, said electrode group comprising: a positive electrode comprising a strip-shaped positive electrode current collector and a positive electrode material mixture layer carried on said positive electrode current collector; a negative electrode comprising a strip-shaped negative electrode current collector and a negative electrode material mixture layer carried on said negative electrode current collector; a separator; and a porous heat resistant layer, said positive electrode and said negative electrode being spirally wound with said separator and said porous heat resistant layer interposed therebetween, wherein said lithium secondary battery has a cylindrical shape or a prismatic shape, said battery case comprises: a first battery can for housing said electrode group; and a second battery can for housing said first battery can, said first battery can covers an entire side surface of said electrode group, said second battery can covers an entire side surface of said first battery can, an insulating layer is disposed between said first battery can and said second battery can, and one of said positive electrode and said negative electrode is electrically connected to said first battery can, and the other electrode is electrically connected to said second battery can.