Patent ID: 11949097

Abstract:
In a nonaqueous electrolyte secondary battery a separator includes a porous substrate, a first filler layer, and a second filler layer. The first filler layer comprises phosphate particles having a BET specific surface area of 5 to 100 m2/g and polyvinylidene fluoride and is formed on a first surface that faces the positive electrode side of the substrate and contacts the positive electrode. The second filler comprises inorganic particles which have a melting point higher than that of the phosphate particles and is formed on at least one of a second surface that faces the negative electrode side of the substrate and the area between the substrate and the first filler layer. The content of the polyvinylidene fluoride in the first filler layer is 10 to 50 mass % and is higher in a region on the positive electrode side than in a region on the substrate side.