Time-dependent range degradation in low-carbon electric vehicle thermal management systems: A quantitative assessment across China

CO2 thermal management systems have become increasingly critical in electric vehicle (EV) applications given the energy efficiency enhancement potential and compatibility with low-carbon technologies. Nevertheless, inherent challenges such as refrigerant leakage and trans-critical operational characteristics create uncertainties regarding the impact on driving range attenuation, limiting practical engineering guidance. To address this gap, a micro-leakage assessment model was established to quantify the effects of daily refrigerant micro-leakage on cabin climate control performance and system stability in typical Chinese cities. The research further analyzes EV range degradation patterns caused by cumulative leakage under diverse urban climate conditions. By incorporating meteorological parameters, spatial correlations between regional climate factors and performance decay rates were mapped, revealing climate-dependent maintenance requirements. Through systematic quantitative evaluation of range attenuation, this work proposes limiting component-level micro-leakage to below 1.5α as a critical threshold. These results provide technical foundations for standardizing CO2 thermal system maintenance protocols, supporting sustainable implementation in EV aftermarket services, and global e-mobility industry development.