BATTERY CELL, BATTERY AND ELECTRICAL DEVICE

A battery cell includes a shell and a pressure relief component, the shell includes a first wall portion, the pressure relief component is disposed on the first wall portion, the pressure relief component includes a first groove and a second groove, the first groove and at least one second groove jointly define at least one predetermined pressure relief region, the pressure relief component is configured to be capable of rupturing along at least a part of the first groove when the battery cell undergoes pressure relief, and the second groove is configured to guide at least a part of the predetermined pressure relief region to be flipped to open the at least a part of the predetermined pressure relief region. A volume of the first groove is V, and a sum of areas of all the predetermined pressure relief regions is A, with 0.05 mm≤V/A≤0.5 mm.