A battery pack, a vehicle, and an energy storage device are provided. The battery pack includes a cell array and a support member, where the cell array includes a plurality of cells, the cell has a first dimension, and the first dimension is a maximum spacing between two imaginary parallel planes sandwiching the cell; and at least one of the cells 600 mm≤first dimension≤2500 mm the at least one cell includes a casing and a core located inside the casing, a supporting region is formed on the casing, and the cell is connected to the support member through the supporting region and is supported by the support member. The support member is connected to the supporting region to support the cell.