Impact of Dual-Objective Control Strategy on Temperature Control in Direct-Cooling System and Energy Flow in Electric Vehicles

Thermal-management systems for electric vehicles have become a key research focus for enhancing cabin thermal comfort and battery performance. This study proposes a direct-cooling system architecture to address the different temperature-response characteristics of cabins and power batteries. A dual-objective temperature-control strategy is developed based on ambient temperature, vehicle operating status, and real-time load temperature information, enabling the dynamic adjustment of thermal-control priorities between the cabin and battery to ensure optimal system performance. A thermal-management system test bench is constructed in an environmental chamber, and a simulation model of the vehicle thermal-management system is developed. Performance comparisons are conducted between the three control strategies under various driving conditions and ambient temperatures. The results demonstrate that the dual-objective strategy exhibits superior temperature-control capability and energy efficiency across different environmental conditions, along with optimal battery state-of-charge (SOC) recovery performance. Under 35 ℃ high-temperature conditions, the cabin and battery reach target temperatures within 51 s and 547 s, respectively. Under -7 ℃ low-temperature conditions, they reach preset values within 127 s and 365 s, respectively, with significantly improved SOC recovery rates. Although the dual-objective strategy slightly increases energy consumption (approximately 1.2%-3.0% higher than the cabin-priority strategy), it substantially enhances the battery thermal-control efficiency and overall system performance, demonstrating high potential for practical applications.