NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery having superior stability in high-temperature circumstances during overcharge. SOLUTION: A plate group having a positive electrode 2 and a negative electrode 3 rolled together with a separator 4 is sealed in a case 5 together with a nonaqueous electrolyte to which an overcharge resistant additive such as 1-(2-biphenyloxy)-2-phenoxyethane is added. The separator 4 between plates has an air permeation resistivity of 700-1500 sec/100 ml and a porosity of 20-70% after held in the atmosphere for 15 minutes at 120 deg.C in the state of giving a tensile load of 25 kg/cm<2> to MD.