Optimization of cooling strategies for an electric vehicle in high-temperature environment

Most electric vehicles (EVs) utilize an active battery thermal management system (ABTMS) to improve the thermal safety of the lithium-ion battery and extend battery life. However, an ABTMS with an inappropriate control strategy cannot slow battery degradation and may even increase the energy consumption. This paper develops a comprehensive EV model with an air-cooling battery pack and proposes a rule-based multiparameter control strategy. On this basis, the effects of critical control parameters (target temperature, temperature fluctuation range, air flowrate, and refrigeration power) on EVs are studied and evaluated regarding the state of health (SoH) and Delta SoH of the battery and the ABTMS energy consumption. The following results were obtained after 2000 days of mixed driving cycles in a high-temperature environment. (1) When the target temperature is reduced by 6 K, the battery degradation rate decreases by 8.9%; however, the driving range decreases by 5.7%. (2) With an appropriate air flowrate, the battery degradation rate decreases by 2.4 - 4.4%, and the driving range increases by 2.1 - 5.5%. (3) The air flowrate more significantly affects the ABTMS than the refrigeration power. These findings help to better guide the parameter settings of this strategy to further slow battery degradation and extend the driving range.