| 摘要 |
PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery whose safety at overcharge is improved. SOLUTION: The nonaqueous electrolyte secondary battery comprises an electrode group 6 wound into a flat shape in which separators 14, 15 are interposed between a positive electrode 7 containing a positive electrode active substance layer and a negative electrode 8 containing a negative electrode active substance layer, and the separators 14, 15 are present at the innermost circumference of the winding. Each separator 14, 15 has a film density of 6 to 12 g/m<SP>2</SP>, and a thermal shrinkage percentage on the exposure to 105°C for 30 minutes is 4% or less in crosswise and longitudinal directions. COPYRIGHT: (C)2005,JPO&NCIPI |
