Research on the Thermal Management System of Extended-Range Electric Vehicles Based on Exhaust Heat Recovery Using Thermal Battery

Abstract

To improve the engine cold start performance and the pure-electric mileage attenuation problem of extended-range electric vehicle (EREV) in low-temperature environments, this paper proposes an improved integrated thermal management system for EREV based on exhaust heat recovery and thermal battery technology. The system recovers exhaust heat through a heat exchanger to warm up the engine or store it in the thermal battery and then uses the stored heat to warm up the cabin and battery during pure-electric driving. The simulation model of the thermal management system has been established and experimentally calibrated. Engine warm-up simulations were carried out in different low-temperature environments (-10℃～10℃), and the results show that compared with the original system, the warm-up time can be shortened by 12.9%～15.2% by using exhaust waste heat alone, and 15.3%～16.6% by using exhaust waste heat and thermal battery together. In addition, at temperatures of -10℃ to 0℃, using Positive Temperature Coefficient (PTC) heater and thermal battery for heating during high State of Charge (SOC) in the pure-electric start-up phase not only saves 21.09% to 37.66% of PTC energy consumption but also results in faster cabin warming rates. Under low SOC conditions at 0℃ ambient temperature, the improved thermal management system can save 13.13% of PTC energy consumption. This paper verifies the feasibility and superiority of applying the engine exhaust waste heat recovery system using thermal battery technology to the EREV thermal management system.

Keywords: Thermal Battery, EREV, thermal management system, Exhaust Heat Recovery