| 摘要 |
PROBLEM TO BE SOLVED: To provide a lithium secondary battery wherein the burst of a laminate film can be prevented in the overcharging. SOLUTION: This battery comprises a power generating element 1 comprising a positive electrode and a negative electrode storing and releasing a lithium ion, a lithium ion conductive electrolyte layer, a positive electrode lead 9 electrically connected to the positive electrode, and a negative electrode lead 10 electrically connected to the negative electrode, and a film 11 which covers the power generating element 1 in such manner that the edge parts of the positive electrode lead 9 and the negative electrode lead 10 are extended outside, and of which an opening part is sealed by the thermal fusion. At least one area 13 having a function of a safety valve, exists on the fusion part of the film 11, and the peel strength of the area 13 having the function as the safety valve, is corresponding to 30-70% of the peel strength of the fusion parts 14 of the positive electrode lead 9 and the negative electrode lead 10. |
