Lithium secondary battery

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 battery case comprises:
• a first battery can for housing said electrode group;
• and a second battery can for housing 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.