Patent ID: 7419743

Claim:
A cylindrical lithium secondary battery comprising: a battery can having a bottom, a side wall, and an open top; an electrode assembly; a non-aqueous electrolyte; and a sealing plate covering the open top of said battery can that accommodates said electrode assembly and said electrolyte, wherein said electrode assembly comprises a strip-like positive electrode and a strip-like negative electrode that are wound together with a porous heat-resistant layer and a separator interposed between the positive and negative electrodes, said positive electrode comprising a positive electrode core member and a positive electrode active material layer carried on each side of the positive electrode core member, said negative electrode comprising a negative electrode core member and a negative electrode active material layer carried on each side of the negative electrode core member, and a thickness A of said porous heat-resistant layer is 2 to 10 μm and a thickness B of the side wall of said battery can is 80 to 300 μm, and A and B satisfy the relation 0.01≦A/B≦0.05.