| 摘要 |
PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery with excellent safety capable of preventing a battery case from expanding or exploding by deriving generated gas from an electrode group even if the electrode group expands due to gas generation. SOLUTION: This nonaqueous electrolyte secondary battery including the columnar electrode group in which a strip negative electrode, a separator and a strip positive electrode are sequentially laminated, a nonaqueous electrolytic solution impregnated into the separator, and the columnar battery case housing the electrode group and the nonaqueous electrolyte has a spacer for forming a grooved uneven part between the electrode group and the battery case in the parallel direction with the axis of the electrode group. Letting L<SB>1</SB>denote the length of the spacer, and L<SB>2</SB>denote the height of the electrode group, the ratio L<SB>1</SB>/L<SB>2</SB>is 0.33-0.99. COPYRIGHT: (C)2004,JPO |
