Patent ID: 8349483

Claim:
A nonaqueous electrolyte secondary battery comprising: a positive electrode plate and a negative electrode plate that contain material able to reversibly absorb and desorb lithium ions; a separator that separates the positive electrode plate and negative electrode plate; and a nonaqueous electrolytic solution in which a solute constituted of lithium salt is dissolved in an organic solvent; the separator being constituted of a polyolefin microporous membrane constituted of three or more layers of stacked film containing polyethylene and polypropylene, the membrane having two surface layers, wherein one is on each of its sides, each of the surface layers having a polypropylene mixture proportion exceeding 50% by mass of the surface layer and containing inorganic particles content of not less than 5% by mass and less than 50% by mass of the surface layer, and the nonaqueous electrolytic solution containing not less than 0.1% by mass and not more than 3.0% by mass, relative to the mass of the nonaqueous solvent of the nonaqueous electrolytic solution, of a dinitrile compound expressed by structural formula (I) below: CN—(CH 2 ) n —CN (I) (where n≧1 and n is an integer).