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 includes a first straight line segment, a second straight line segment and a circular arc segment. Two ends of the circular arc segment are respectively connected to the first straight line segment and the second straight line segment. Lengths of the first straight line segment and the second straight line segment are respectively a and b, and an arc length of the circular arc segment is c, a radius of curvature of the circular arc segment is r, and 0.8≤a/b≤1.2 and 0.5≤c/r≤2.7 are satisfied.