The utility model discloses a single battery and a
battery pack. The single battery comprises a shell, a top cover
assembly, a
battery cell and a connecting piece, the shell is provided with a containing cavity with an opening in one end, the top cover
assembly is connected to the shell and seals the opening, the
battery cell is arranged in the containing cavity, and the end, facing the top cover
assembly, of the
battery cell is provided with a tab; the connecting piece comprises a connecting part, the connecting part is provided with a first section and a second section which are connected, the first section is connected with the top cover assembly, the tab is wound on the circumferential outer side of the second section, the second section is provided with an accommodating space, and one end, far away from the battery
cell, of the tab is arranged in the accommodating space. Therefore, by utilizing the
insertion matching of the accommodating space and the end part of the tab, the winding operation of the tab on the outer side of the connecting part is facilitated, the connection firmness of the tab and the connecting piece can be increased, the contact area of the tab and the electric connecting piece can be increased, and the
overcurrent capacity between the battery
cell and the electric connecting piece is improved.