NONAQUEOUS SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a nonaqueous secondary battery having a superior load characteristic and high charge and discharge efficiencies.SOLUTION: A nonaqueous secondary battery comprises: a positive electrode having a positive electrode active material layer on each or one of opposing surfaces of a collector; a negative electrode having a negative electrode active material layer on each or one of opposing surfaces of a collector; and a nonaqueous electrolyte containing a lithium salt and an organic solvent. The nonaqueous electrolyte contains LiBFas the lithium salt at a concentration of 0.3 mol/dmor more, and acetonitrile as the organic solvent. In the organic solvent, the content of the acetonitrile is 20 vol.% or more. The ratio of the area of the whole negative electrode active material layer to the area of a part of the positive electrode active material layer opposed to the negative electrode active material layer is between 1.0 and 1.1.