Battery cell, battery, and electric device

A battery cell, comprising:

• a housing comprising a first wall portion, wherein the first wall portion is provided with a lead-out hole running through the first wall portion;
• an electrode terminal comprising a body portion and a flange portion, wherein the body portion is at least partially inserted into the lead-out hole;
• and along a thickness direction of the first wall portion, the flange portion is connected to one end of the body portion, the flange portion is located on one side of the first wall portion, and the flange portion has a first end surface facing away from the body portion;
• the electrode terminal is provided with a groove, and the groove has a first groove side surface connected to the first end surface;
• and
• a first connector welded to the electrode terminal to form a weld mark portion, wherein a portion of the first groove side surface located in the flange portion does not contact the weld mark portion,
• wherein the groove has a second groove side surface, and along the thickness direction, the second groove side surface is located on a side of the first groove side surface facing away from the first end surface;
• and
• the first connector comprises a first connecting portion, the first connecting portion is at least partially accommodated in the groove, the first connecting portion has a first outer circumferential surface, and the first outer circumferential surface is welded to the second groove side surface to form the weld mark portion.