A Dynamic Simulation Framework for the Analysis of Battery Electric Vehicle Thermal Management Systems

Abstract

As vehicle electrification is expanding in response to more stringent emissions standards and shifting consumer preferences, extending the driving range remains critical to broadening the adoption of battery electric vehicles (BEV). This challenge can be addressed in part through more efficient operation of the thermal management system in BEVs, which has a significant influence on range and performance, especially under extreme weather conditions. This study develops a simulation framework for the analysis of a BEV thermal management systems under long-range test procedures defined by the Multi-Cycle Test (MCT). A baseline thermal management system configuration is defined to reflect those typically found in long-range BEVs, so as to provide insight into the design and performance of current systems. Parametric studies are conducted across a range of ambient conditions from 0 °C to 40 °C and drive cycles including urban/city (UDDS), highway (HFEDS), and constant speed cycles. Operating temperature setpoints for the cabin, battery, electronics, and other components are met using the standard system configuration, albeit with significant deleterious impacts on vehicle range and cycle control. At low ambient temperatures, a maximum 30% decrease in driving range is predicted. Across the parametric values investigated, the choice of cabin setpoint temperature affects the driving range on the order of ~10% across heating and cooling cases. The transient drive cycle response for representative cooling cases is presented and reveals oscillations in system behavior about the chosen setpoints; these oscillations are a direct result of the secondary loop liquid cooling architecture. As a result of the present study, perspectives on alternative system configurations that offer battery thermal management and cabin comfort as well as the integration of waste heat recovery are outlined as future work.