Secondary battery

摘要

A secondary battery can prevent microscopic short circuit due to shedding of active material from an electrode and secure electric connection between the electrode and an electrode terminal. According to an example of means for preventing shedding of active material from a positive electrode 1 constituting a wound type electrode unit 7, a negative electrode side of a separator 3 is bent toward a center of the electrode unit 7. The negative electrode 2 having a flex substrate is provided with an electrode end portion 4′ with almost no active material. At least a part of the electrode end portion 4′ is exposed from the bent separator 3, and the exposed electrode end portion 4′ is electrically connected to a battery terminal or a battery case 8 directly or via a negative electrode collector plate 6.