BATTERY PACK

A battery pack includes a cell assembly. The cell assembly includes a cell assembly positive terminal, a cell assembly negative terminal, a positive lead-out piece, a negative lead-out piece, a discharge path, and a protective element. The positive lead-out piece connects the cell assembly positive terminal to a battery pack positive terminal. The negative lead-out piece connects the cell assembly negative terminal to a battery pack negative terminal. The protective element is disposed on the discharge path. When the discharge current of the discharge path is greater than or equal to a preset current, the protective element turns off. The length of one of the positive lead-out piece or the negative lead-out piece close to the protective element is greater than the length of the other one of the positive lead-out piece or the negative lead-out piece away from the protective element.