| 摘要 |
PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery superior in overcharge resistance while ensuring battery characteristics; and a battery pack including the nonaqueous electrolyte secondary batteries (as unit cells).SOLUTION: According to the present invention, a nonaqueous electrolyte secondary battery is provided, which comprises: a flat wound electrode body 10 including elongated positive and negative electrode sheets, and an elongated separator sheet serving to electrically isolate the negative electrode sheet. A binding pressure "a"(kg/cm) acts on the wound electrode body in a direction orthogonal to a flat face 10F of the wound electrode body; the binding pressure "a"(kg/cm) in a range given by: 2≤a≤62. In addition, the thermal shrinkage "b"(%) of the separator sheet in a lengthwise direction at 150°C is in a range given by: 0.5≤b≤30. Further, the product (a×b) of the binding pressure "a"(kg/cm) and the thermal shrinkage "b"(%) is in a range given by: 4≤(a×b)≤800. |
