Patent ID: 8530072

Claim:
A lithium secondary battery comprising an electrode group, a non-aqueous electrolyte and a battery can 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 positive electrode material mixture layers carried on both sides of said positive electrode current collector; a negative electrode comprising a strip-shaped negative electrode current collector and negative electrode material mixture layers carried on both sides of 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 positive electrode current collector or said negative electrode current collector is exposed over an entire outermost surface of said electrode group, the exposed current collector faces an inner surface of said battery can with said separator but without said porous heat resistant layer interposed therebetween, and has opposite polarity to that of said battery can, and said porous heat resistant layer contacts an entire surface of the positive electrode material mixture layer or an entire surface of the negative electrode material mixture layer.