1. School of Mechanical Engineering, Beijing Institute of Technology, Beijing, China
2. College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, China
3. Collaborative Innovation Center of Electric Vehicles in Beijing, Beijing, China
4. Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, IL, USA
5. School of Electrical and Mechanical Engineering, Beijing Information Science and Technology University, Beijing, China