An optimal thermal management system heating control strategy for electric vehicles under low-temperature fast charging conditions

Abstract

• An improving fast charging protocol is proposed to avoid lithium plating. • A multi-stage heating control strategy based on the battery temperature is developed. • Dual crucial objectives, heating energy consumption and charging time are balanced. • An optimal heating control strategy for low-temperature fast charging is proposed. • The optimal control strategy can reduce heating energy consumption by 11.61%. Electric vehicle thermal management system (EVTMS) and its corresponding control strategy are essential to ensure the battery performance at low temperatures. Due to the complexity of the low-temperature fast charging process, it is necessary to comprehensively consider the battery heating and charging performance when developing the heating strategy. However, most studies only focus on the charging time. In this context, an EVTMS is investigated in this paper, and the simulation models are established. In addition, the battery heating and charging performance under low-temperature fast charging conditions are analyzed by experiment and simulation. An improved fast charging protocol for reducing the battery-lifetime degradation is proposed. Moreover, an EVTMS multi-stage heating control strategy is developed to realize the cooperative control with the improved charging strategy. Taking dual crucial yet conflicting factors, heating energy consumption and charging time, as the optimization objectives, the proposed EVTMS control strategy is optimized using genetic algorithm. And an optimal heating control strategy is obtained. The results show that compared with the strategy only considering the charging time, the optimal strategy can reduce the heating energy consumption by 11.61% and increase the charging efficiency by 1.2%, only with the increase of the charging time by 2.98 min.