Battery monomer, battery and electric device

The utility model provides a battery monomer, a battery and a power utilization device, and the battery monomer comprises an electrode assembly which comprises at least one positive pole piece and at least one negative pole piece; the shell is used for accommodating the electrode assembly, the shell comprises a first wall part, the first wall part is provided with a pressure relief part, and the pressure relief part is configured to be capable of releasing the pressure in the battery monomer; wherein the positive pole piece comprises a positive active material region, and the positive active material region and the inner surface of the first wall part are arranged at an interval along the second direction. In the technical scheme of the embodiment of the invention, the positive active material region is separated from the inner wall surface of the first wall part, so that the pulling force and the deformation of the first wall part due to expansion deformation of the electrode assembly can be reduced, the probability that the pressure relief part is damaged by pulling is further reduced, the probability of liquid leakage at the pressure relief part is reduced, and the reliability of the battery is improved. The reliability of the battery monomer is improved.