Publication

Electrochemical Application For
Advanced Energy System Labortary.

Journal

Study on oil cooling method for the powertrain of electric vehicles
Author
Youngkyo Kim
Co-author
Tae Young Beom, Tae Wook Ha, Sung Wook Lee, In Guk Hwang, Dong Kyu Kim
Journal
International Journal of Heat and Mass Transfer
Vol
246
Page
127073
Year
2025

This study presents a thermal-fluid analysis of an electric vehicle (EV) powertrain to evaluate the effectiveness and limitation of oil cooling. A validated numerical model was developed to investigate oil flow behavior, churning effects, and temperature distribution. Results show uneven oil distribution in the motor chamber. Only 22.6 % of the cooling oil reached the drive-end winding, while 46 % reached the non-drive end. As a result, the drive end experienced a 4.2 % higher temperature than the non-drive end. The stator temperature was 4.9 % higher than the windings, and the rotor exhibited the highest temperature due to inefficient heat dissipation. Additionally, oil recirculation from the reducer (0.02 L/s) reduced cooling efficiency, particularly under high-load conditions. These findings provide critical insights into the thermal challenges of EV powertrains and serve as a foundation for optimizing oil flow, developing hybrid cooling strategies, and improving thermal management in next-generation EVs.