Battery cell, battery and electric device

The utility model provides a battery monomer, a battery and a power utilization device. The battery monomer comprises a shell and an end cover assembly, the shell is provided with an opening, the end cover assembly comprises an end cover, an insulating part and an inner pole, the end cover is arranged at the opening, and an annular bulge extending along the circumferential direction of the end cover is arranged on the surface, close to the shell, of the end cover; the end cover is provided with an annular protrusion, the annular protrusion retracts inwards relative to the edge of the end cover so that a flange edge can be formed between the outer side of the annular protrusion and the edge of the end cover, the flange edge is arranged on the shell wall of the shell, the annular protrusion extends into the shell, the insulating part is arranged in a groove defined by the annular protrusion, and the inner pole is arranged on the insulating part. According to the battery monomer, the annular bulge is arranged on