SECONDARY BATTERY AND BATTERY ASSEMBLY

摘要

PROBLEM TO BE SOLVED: To provide a technique of preventing performance degradation of a secondary battery.SOLUTION: The secondary battery is housed in a case 4a and includes: an electrode body 2 flatly wound; and an insulation film 3 disposed between a side face 2d having a maximum area of the electrode body and an inner face of the case 4a. The thickness of the electrode body 2 at the center in the direction of the winding axis is larger than thicknesses at both ends of the electrode body.