| 摘要 |
PROBLEM TO BE SOLVED: To provide a square secondary battery which does not disturb gas exhaustion even while securing an insulation quality.SOLUTION: The square secondary battery comprises: a winding group in which a positive electrode and a negative electrode are wound flatly via a separator; a battery can which accommodates the winding group therein and includes an opening; and a battery lid which closes the battery can and in which a gas exhaust valve is disposed. A flexible insulation film is adhered to an outer circumference of the battery can, the insulation film covers the battery lid and includes a joint part where the insulation films are joined with each other, at a side of the battery lid and the joint part is disposed closer to an end portion of the battery lid than the gas exhaust valve.SELECTED DRAWING: Figure 5 |
