Energy Flow Study of Pure Electric Vehicles under Different Temperature Conditions

Aiming at the problem of significant range degradation of pure electric vehicles in low-temperature environments, this study reveals the influence law of temperature on the distribution mechanism of energy consumption and the range by means of vehicle energy flow tests at $23^{\circ} \mathrm{C},-7^{\circ} \mathrm{C}$ and $-20^{\circ} \mathrm{C}$. The experiments show that at $20^{\circ} \mathrm{C}$, the heat pump fails and relies on the PTC to supply heat, which triggers the air pump to operate at high load. At -7 degrees Celsius, the heat pump is the first to start heating. Low temperatures simultaneously lead to an increase in low-pressure accessory energy consumption and a decrease in the proportion of high-pressure drive energy. As a result, the range of CLTC-P under operating conditions decreased from 710.58 km at 23° Cto 280.21 km at $-20^{\circ} \mathrm{C}($ a $60.57 \%$ decrease), and the power consumption increased dramatically from 15.44 kWh to 37.33 kWh per 100 km. The research results provide a theoretical basis for optimizing the low-temperature adaptability and energy distribution strategy of heat pumps.