An energy storage system that comprises a multi-stage short-circuit protection system, a battery cabinet, a direct-current combiner box and a power conversion device, the multi-storage short-circuit protection system comprising N stages of fuse units, wherein N is a positive integer greater than two, and wherein each of a plurality of battery packs in the battery cabinet of the energy storage system is configured to transmit electric energy through a branch in which a first-stage fuse unit corresponding to the battery pack is arranged, the plurality of battery packs is connected to a direct-current side positive-negative copper busbar of the power conversion device of the energy storage system by sharing at least one branch in which a second-stage fuse unit is arranged, the direct-current side positive-negative copper busbar of the power conversion device is connected to a main circuit of the power conversion device at a direct-current side of the power conversion device through a branch in which a third-stage fuse unit is arranged, and in a case that a short circuit fault occurs at a position on the direct-current side of the power conversion device of the energy storage system, a fuse unit at a stage preceding the position and a fuse unit at a stage following the position are broken; characterized in that, the direct-current combiner box of the energy storage system comprises p combiner units, and each of the p combiner units comprises one output positive-negative copper busbar and q input copper positive-negative busbars, wherein p and q are positive integers, each of the q input positive-negative copper busbar is configured to transmit electric energy between n battery packs and the output positive-negative copper busbar, wherein n is a positive integer; and the output positive-negative copper busbar is connected to the direct-current side positive-negative copper busbar of the power conversion device of the energy storage system through the branch in which the second-stage fuse unit is arranged; wherein N is equal to 4, and for each of the p combiner units, each of the q input positive-negative copper busbars in the combiner unit is connected to the output positive-negative copper busbar in the combiner unit through a branch in which a fourth-stage fuse unit is arranged, a rated current of the first-stage fuse unit is less than a rated current of the fourth-stage fuse unit, the rated current of the fourth-stage fuse unit is less than a rated current of the second-stage fuse unit, and the rated current of the second-stage fuse unit is less than a rated current of the third-stage fuse unit. each of a plurality of battery packs in the battery cabinet of the energy storage system is configured to transmit electric energy through a branch in which a first-stage fuse unit corresponding to the battery pack is arranged, the plurality of battery packs is connected to a direct-current side positive-negative copper busbar of the power conversion device of the energy storage system by sharing at least one branch in which a second-stage fuse unit is arranged, the direct-current side positive-negative copper busbar of the power conversion device is connected to a main circuit of the power conversion device at a direct-current side of the power conversion device through a branch in which a third-stage fuse unit is arranged, and in a case that a short circuit fault occurs at a position on the direct-current side of the power conversion device of the energy storage system, a fuse unit at a stage preceding the position and a fuse unit at a stage following the position are broken; characterized in that, the direct-current combiner box of the energy storage system comprises p combiner units, and each of the p combiner units comprises one output positive-negative copper busbar and q input copper positive-negative busbars, wherein p and q are positive integers, each of the q input positive-negative copper busbar is configured to transmit electric energy between n battery packs and the output positive-negative copper busbar, wherein n is a positive integer; and the output positive-negative copper busbar is connected to the direct-current side positive-negative copper busbar of the power conversion device of the energy storage system through the branch in which the second-stage fuse unit is arranged; wherein N is equal to 4, and for each of the p combiner units, each of the q input positive-negative copper busbars in the combiner unit is connected to the output positive-negative copper busbar in the combiner unit through a branch in which a fourth-stage fuse unit is arranged, a rated current of the first-stage fuse unit is less than a rated current of the fourth-stage fuse unit, the rated current of the fourth-stage fuse unit is less than a rated current of the second-stage fuse unit, and the rated current of the second-stage fuse unit is less than a rated current of the third-stage fuse unit.