| 摘要 |
PROBLEM TO BE SOLVED: To provide a rectangular nonaqueous electrolyte secondary battery restraining inflation during preservation at high temperatures and an increase in impedance while maintaining various characteristics such as cycle characteristic. SOLUTION: In a rectangular nonaqueous electrolyte secondary battery having a positive electrode 6, a negative electrode 4, a separator 5 and a nonaqueous electrolytic solution, the nonaqueous electrolytic solution contains lithium tetrafluoroborate with a concentration of 0.05 to 0.3 mol/L and a lithium hexafluorophosphate electrolyte with a concentration of 0.75 mol/L or more, with the total concentration of the electrolyte 1.3 mol/L or less. |
