BATTERY

A battery includes an explosion-proof valve and a battery casing. The explosion-proof valve is arranged in the battery casing. The explosion-proof valve is arranged on a first surface of the battery casing, the explosion-proof valve includes a fragile portion. The fragile portion protrudes toward a middle region of the first surface. The fragile portion includes a first end point and a second end point, and an area jointly enclosed by a connection line between the first end point and the second end point and the fragile portion between the first end point and the second end point is a. A minimum distance between the first end point and a circumferential edge of the first surface is b. A minimum distance between the second end point and the circumferential edge of the first surface is c.