| abstract |
In the case where a film having lower strength than a metal can is used as an exterior body of a secondary battery, a current collector provided in a region surrounded by the exterior body, an active material layer provided on a surface of the current collector, or the like might be damaged when force is externally applied to the secondary battery. A secondary battery resistant to external force is provided. A cushioning material is provided in a region sandwiched by an exterior body of the secondary battery. Specifically, the cushioning material is provided on the periphery of an electrode group including a positive electrode current collector, a positive electrode active material layer formed on at least one surface of the positive electrode current collector, a separator, a negative electrode current collector, and a negative electrode active material layer formed on at least one surface of the negative electrode current collector. |