Comprehensive performance analysis of electric vehicle advanced cabin moisture-thermal coupling management control strategies based on transcritical CO₂ cycle

The development of an advanced cabin moisture-thermal coupling management system, along with its operation dynamic control strategy, is essential for ensuring passenger comfort, driving safety, and the driving range of electric vehicles. Based on the transcritical CO₂ cycle, an independent thermal management (ITM) system and two (the single-stage throttling (SST) and double-stage throttling (DST)) moisture-thermal coupling management systems are proposed. First, an anti-fog evaluation standard is established, and regions with different controls are defined across the winter operating conditions. Subsequently, the thermodynamic characteristics are analyzed, the SST moisture-thermal coupling management cycle features an optimal discharge pressure that minimizes both power consumption and cabin humidity. In contrast, the cabin humidity in the DST cycle is regulated by intermediate pressure, which has both upper and lower limits. The optimal discharge pressure increases, while the minimum intermediate pressure decreases with ambient temperature. Furthermore, a performance comparison of two moisture-thermal coupling management cycles is conducted. From a moisture management perspective, the SST cycle's moisture extraction rate and specific moisture extraction rate are significantly improved by 7 and 12.5 times, respectively. However, the DST cycle's COP is superior. Given that passenger comfort and driving safety take precedence over energy efficiency, the SST cycle is deemed the more suitable choice. Lastly, the dynamic response characteristics of the SST cycle are investigated using the WLTC. Moreover, the impact of the SST cycle on the driving range is analyzed. The winter driving range of the SST cycle is slightly lower compared to the ITM cycle, but it increases by approximately 5.17 % compared to the traditional PTC thermal management system. This study provides valuable insights into the dynamic characteristics of efficient cabin energy management systems in electric vehicles and introduces a novel approach for multi-objective coupling control during winter driving.