A battery pack for optimizing the structure of the battery pack includes a case, a battery module and a blocking member. The case includes an accommodating cavity and a drain hole in communication with the accommodating cavity. The battery module is contained inside the accommodating cavity. The blocking member is mounted to the case, wherein the blocking member is disposed on one side of the battery module in a width direction. At least a part of the blocking member is arranged between the battery module and the drain hole to block a binder for fixing the battery module from entering the drain hole. The reservoir cavity is provided, such that the liquid flow into a reservoir portion to prevent dangers such as short-circuit occurring in the battery module when liquid is accumulated inside the case.