Battery pack and power device with same

The utility model discloses a battery pack and its power plant, the battery pack includes shell, battery cell subassembly and first foaming piece, the shell includes bottom plate and is connected to the boundary beam on the bottom plate, boundary beam and bottom plate cooperate to form in the shell in the accommodation cavity of upward opening, the accommodation cavity is filled with immersion liquid, the immersion liquid is filled with the battery cell subassembly, the immersion liquid is filled with the battery cell subassembly, and the first foaming piece is filled with the battery cell subassembly. The height of the immersion liquid is smaller than that of the containing cavity, the battery cell assembly and the first foaming part are arranged in the containing cavity, and the first foaming part is located on the upper surface of the immersion liquid. According to the battery pack disclosed by the embodiment of the utility model, the height of the immersion liquid is set to be smaller than that of the acc