A battery pack includes a case and a battery module. The case includes an accommodating cavity and a drain hole in communication with the accommodating cavity. The battery module is mounted inside the accommodating cavity. A reservoir cavity is provided below the battery module to store a liquid, and in communication with the drain hole. A reservoir cavity is provided, such that the liquid can flow into a reservoir portion to prevent dangers such as short-circuit occurring in the battery module inside the case, and optimize the structure and performance of the battery pack when liquid is accumulated inside the case.