Nonaqueous electrolyte secondary battery

A nonaqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, a battery case, a positive electrode terminal, a negative electrode terminal, a safety valve and a nonaqueous electrolytic solution, wherein

• the battery case is a flat angular battery case,
• the positive electrode terminal, the negative electrode terminal, and the safety valve are provided on a same face of the battery case,
• the positive electrode includes a positive electrode active material layer;
• the positive electrode active material layer includes Li3PO4, Li2WO4, and, as a positive electrode active material, a lithium transition metal complex oxide including at least lithium, nickel, manganese, and cobalt;
• a mass ratio of Li3PO4 to the positive electrode active material is 1% by mass or more and 3% by mass or less;
• a mass ratio of Li2WO4 to the positive electrode active material is 0.5% by mass or more and 0.9% by mass or less;
• an average particle diameter of the Li3PO4 is 1 μm or more and 10 μm or less;
• an average particle diameter of the Li2WO4 is 0.01 μm or more and less than 0.1 μm;
• the lithium transition metal composite oxide is represented by a following Formula (I):
• LiaNixMnyCozO2 (I),
• wherein, in Formula (I), a satisfies 0.98≤a≤1.20;
• x, y, and z satisfy x+y+z=1;
• x satisfies 0.20≤x≤0.60;
• y satisfies 0<y≤0.50;
• and z satisfies 0<z≤0.50;
• the negative electrode includes a negative electrode active material layer;
• the negative electrode active material layer includes a negative electrode active material, a binder, and a thickener;
• the negative electrode active material of the negative electrode active material layer consists essentially of graphite;
• a content of the graphite in the negative electrode active material layer is 95% by mass or more and 99% by mass or less,
• the binder includes styrene butadiene rubber;
• a content of the styrene butadiene rubber in the negative electrode active material layer is 0.5% by mass or more and 3% by mass or less,
• the thickener includes carboxymethyl cellulose, and
• a coating film derived from decomposition of both Li3PO4 and Li2WO4 and including phosphorus atoms and tungsten atoms is formed on the positive electrode active material.