US Patent 9478784 Nonaqueous electrolyte secondary battery

A nonaqueous electrolyte secondary battery includes an electrode body, a non-aqueous electrolyte and a porous heat resistance layer. The electrode body is provided with a positive electrode and a negative electrode that face each other through a separator. The porous heat resistance layer is disposed at least in one of a space between the positive electrode and the separator and a space between the negative electrode and the separator and contains an inorganic filler. A porosity of the separator is not less than 70% by volume and not more than 80% by volume. A ratio of a porosity of the porous heat resistance layer with respect to the porosity of the separator is not less than 0.3 and not more than 0.6.