A power assembly, comprising: a transmission comprising a transmission housing and a transmission input shaft rotatably connected to the transmission housing, the transmission housing having a through hole; a motor comprising: a motor housing having an open end and a closed end opposite to the open end, and the open end being connected to the transmission housing; a rotor rotatably arranged in the motor housing; a motor output shaft having an end connected to the rotor and another end passing through the through hole to be connected to the transmission input shaft; and a stator fixed in the motor housing and arranged on a peripheral outer side of the rotor; and a heat conductive element arranged between an end of the stator and the transmission housing, wherein the heat conductive element comprises a heat conductive washer, one end of the heat conductive washer is in contact with the transmission housing, and the other end of the heat conductive washer opposite to the one end of the heat conductive washer is in contact with the end of the stator, wherein the heat conductive washer is annular, the transmission housing has a cooling ring face matched with the heat conductive washer in shape, and the heat conductive washer is fitted with the cooling ring face, characterized in that the heat conductivity of the heat conductive washer is higher than a thermal conductivity of air, and the heat conductive washer is made of an insulating material, wherein an accommodating chamber is formed in an outer surface of the transmission housing, the through hole is formed in a bottom wall of the accommodating chamber, the open end of the motor housing is connected to a peripheral wall of the accommodating chamber, and the cooling ring face is arranged on the bottom wall of the accommodating chamber. a transmission comprising a transmission housing and a transmission input shaft rotatably connected to the transmission housing, the transmission housing having a through hole; a motor comprising: a motor housing having an open end and a closed end opposite to the open end, and the open end being connected to the transmission housing; a rotor rotatably arranged in the motor housing; a motor output shaft having an end connected to the rotor and another end passing through the through hole to be connected to the transmission input shaft; and a stator fixed in the motor housing and arranged on a peripheral outer side of the rotor; and a motor housing having an open end and a closed end opposite to the open end, and the open end being connected to the transmission housing; a rotor rotatably arranged in the motor housing; a motor output shaft having an end connected to the rotor and another end passing through the through hole to be connected to the transmission input shaft; and a stator fixed in the motor housing and arranged on a peripheral outer side of the rotor; and a heat conductive element arranged between an end of the stator and the transmission housing, wherein the heat conductive element comprises a heat conductive washer, one end of the heat conductive washer is in contact with the transmission housing, and the other end of the heat conductive washer opposite to the one end of the heat conductive washer is in contact with the end of the stator, wherein the heat conductive washer is annular, the transmission housing has a cooling ring face matched with the heat conductive washer in shape, and the heat conductive washer is fitted with the cooling ring face, characterized in that the heat conductivity of the heat conductive washer is higher than a thermal conductivity of air, and the heat conductive washer is made of an insulating material, wherein an accommodating chamber is formed in an outer surface of the transmission housing, the through hole is formed in a bottom wall of the accommodating chamber, the open end of the motor housing is connected to a peripheral wall of the accommodating chamber, and the cooling ring face is arranged on the bottom wall of the accommodating chamber.