Research on cooperative thermal management of air conditioning system and battery liquid cooling system for pure electric vehicle

A synergistic dual-evaporator thermal management model integrating joint battery and cabin cooling is proposed for the problem of battery thermal safety and cabin thermal comfort in pure electric vehicles. The synergistic dual-evaporator system can dynamically adjust the evaporator operating state and refrigerant flow rate by innovating the refrigerant flow path and applying an intelligent control strategy to optimize the energy efficiency of the system. Based on the whole-vehicle thermal management system framework, the study was conducted under four different driving conditions and different high-temperature climatic conditions. The results indicate that the thermal regulation of the dual-evaporator system can be accomplished through dual control of the electronic expansion valve and compressor. In a high-temperature environment of 41.5°C, the battery and cabin temperatures can drop to 25°C and stabilize within 2400 seconds and 440 seconds. Battery module temperature difference is controlled within 1°C. The PMV index converged to +0.5, the PPD index converged to 10%, and the system energy efficiency ratio was maintained at 3.2 to 4.6 under system test conditions. The system energy efficiency ratio is negatively correlated with the ambient temperature, and the more stable the vehicle driving conditions, the higher the system energy efficiency ratio.