The motor is the key component of the flywheel energy storage system to realize the conversion of electric energy and kinetic energy. In order to improve the efficiency of the flywheel energy storage system

the motor rotor is usually operated in a vacuum environment. However

the heat generated by the rotor can only be transmitted outward through thermal radiation in a vacuum environment and the radiation heat transfer intensity is very low. This makes the heat generated by the rotor difficult to disperse

resulting in a continuous increase in the rotor temperature and even causes the demagnetization of the magnetic steel to damage the motor. Therefore

this paper proposes a low-temperature evaporative cooling scheme on the stator side of the flywheel motor and a high-radiation coating scheme on the rotor side. The effects of low temperature on the stator side and high radiation coating on the rotor side on the temperature rise of the rotor are mainly investigated. The enhancement effect of the proposed scheme on the radiation heat transfer of the motor rotor is verified by experiments. The experimental results show that only the rotor temperature is reduced by 1 °C after the stator side temperature is reduced by 15 °C. The improvement effect on the radiation heat transfer intensity is not significant. After coating the high radiation coating

the stator side temperature is reduced by 15 °C

the rotor temperature is reduced by nearly 3 °C and the cooling effect is significantly improved. The combination of low-temperature evaporative cooling on the stator side and high-radiation coating on the rotor side can further enhance the radiation heat transfer and obtain better cooling effect.