The battery and the center pin

When crushed to external forces, it is possible to short-circuit the more reliably the electrodes, to provide improved battery safety. The positive electrode and the negative electrode are layered with a separator, the center of the produced wound body by winding spirally, center pin (30) is inserted. The center pin (30), which has a cut (31) provided in the longitudinal direction and has a first notch (32) crossing perpendicularly to the cuts (31). When squeezed by an external force, cut (31) and the corners of the intersection of the first notch (32) (33) protrude, to generate a reliable short circuit. Further, at a position facing the slit (31) in the circumferential direction, preferably it has a second notch (34) in a direction perpendicular to the slit (31). Center pin (30) an elliptical or oval cross-sectional shape, it is also preferable that the diameter of an ellipse or oval cut (31) is provided in the most significant position.