A stator assembly includes a stator core including teeth, which are formed along an inner circumferential surface of the stator core, extend from one surface of the stator core to an opposite surface of the stator core, and have through holes formed through one surfaces of the teeth, respectively, a plurality of hairpins, each hairpin coupled to and connected with a slot formed between the teeth facing each other and forming form a coil winding, and a heat radiating device including a first heat radiating member provided at one side of the one surface of the stator core to discharge heat of the hairpin to an outside, such that the hairpin is cooled.