Battery cell, battery, and electric device

A battery, comprising a plurality of battery cells, each battery cell of the plurality of battery cells comprising:

• a housing comprising a wall portion, the wall portion having an outer surface and being provided with an accommodating recess recessed with respect to the outer surface;
• a pressure relief mechanism provided at the wall portion, the pressure relief mechanism being capable of being actuated to release gas within the housing in a case where an internal pressure or temperature of the battery cell reaches a threshold value;
• a protective member having a melting point greater than or equal to 300° C., the protective member covering at least part of the pressure relief mechanism in a thickness direction of the wall portion, at least a part of the protective member being accommodated in the accommodating recess;
• and
• a connection layer through which the protective member is connected to the wall portion,
• wherein a stepped surface is provided on a side wall of the accommodating recess, and the connection layer is located between the stepped surface and the protective member to connect the protective member to the wall portion,
• the connection layer is provided at an outer peripheral region of a surface of the protective member facing the pressure relief mechanism, an avoidance space is formed between the protective member and the pressure relief mechanism, a communication flow path is provided between the protective member and the wall portion, one end of the communication flow path communicates with an outside, and the other end of the communication flow path communicates with the avoidance space, the communication flow path comprises a single groove, facing the pressure relief mechanism, provided in a surface of the protective member,
• in the thickness direction, the connecting layer is not overlapped with the groove to reduce risk of filling the connecting layer into the groove.