BATTERY PACK

Provided is a battery pack. The 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 discharge path is configured to supply power to a power tool and consists of the cell assembly positive terminal, the positive lead-out piece, the battery pack positive terminal, the cell assembly negative terminal, the negative lead-out piece, and the battery pack negative terminal. The protective element is disposed on the discharge path. In response to the discharge current of the discharge path being greater than or equal to a preset current, the protective element turns off to disconnect the discharge path. 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. The preceding technical solutions can reduce the heat generation of the battery pack, thus improving the safety and reliability of the battery pack and extending the service life of the battery pack.