A battery cell is provided. The battery cell includes a tab, an electrode terminal, an adapter for electrical connection between the electrode terminal and the tab. The adapter includes a first connecting portion for electrical connection with the electrode terminal; a second connecting portion for electrical connection with the tab; a third connecting portion for connecting the first connecting portion and the second connecting portion; and a bending portion, the third connecting portion is connected with the first connecting portion by the bending portion and the third connecting portion is connected with the second connecting portion by the bending portion; the third connecting portion includes a reinforcing portion, and the reinforcing portion is located at the connection of the third connecting portion and the bending portion; the minimum distance L from an edge of the reinforcing portion to a center line of the bending portion satisfies: R