Embodiments of this application provide a stator element, a stator assembly, a motor, and an electromechanical device, the stator element including at least two stacked stator housing sheets, each of the stator housing sheets being a frame enclosed by a sheet periphery, at least two protrusions being disposed around the periphery of each of the stator housing sheets, the protrusion being directed from an inside of the stator housing sheet to an outside of the stator housing sheet, a groove being formed between adjacent protrusions, and protrusions of the adjacent stator housing sheets being alternately arranged in a direction in which the at least two stator housing sheets are stacked. Therefore, heat of a stator disposed inside the stator element can be dissipated with a strong heat dissipation capability at relatively low costs.