SECONDARY BATTERY

A thermal expansion coefficient of the battery case is lower than those of the insulating film (10) and the separator. Portions of the insulating film (10), which are held in contact with the electrode body (80) and the battery case, are adhered to the separator, which is positioned on the outermost surface of the electrode body (80), and the battery case, respectively. A first 90 degree peeling strength of an adhesion portion between the insulating film (10) and the battery case is higher than a second 90 degree peeling strength of an adhesion portion between the insulating film (10) and the separator. The first 90 degree peeling strength is 15 mN/cm or higher, and the second 90 degree peeling strength is 5 mN/cm or higher.