Battery cell, battery, and electrical device

A battery, comprising a housing and a battery cell disposed in the housing, wherein,

• the battery cell comprises a first electrode plate;
• the first electrode plate comprises a first current collector and a first active material layer;
• the first current collector comprises a first surface;
• the first active material layer comprises a first part and a second part;
• a length direction of the first current collector is a first direction, the first part and the second part are disposed spaced apart from each other on the first surface along the first direction;
• a first groove is formed between the first part and the second part to expose the first surface;
• along the first direction, a first thinned region is disposed at a position adjacent to the first groove in the first part;
• a second thinned region is disposed at a position adjacent to the first groove in the second part;
• a thickness direction of the first current collector is a second direction;
• along the second direction, a thickness of the second thinned region is greater than a thickness of the first thinned region;
• the battery cell further comprises a first adhesive layer;
• the first adhesive layer is bonded to the first thinned region and extends from the first thinned region to the second thinned region;
• a part of the first adhesive layer covers the first groove;
• and
• along the first direction, a length L1 by which the first adhesive layer is bonded to the first thinned region is less than a length L2 by which the first adhesive layer is bonded to the second thinned region.