Less Winter Cruising Range Loss for Electric Vehicles

Electric Vehicles present challenges for thermal management throughout the year. It should place as light a load on the drivetrain battery as possible, especially in wintertime. Mahle has developed a compact system based on a heatpump that can increase the winter cruising range by up to 20 percent.

Due to the lack of steadily available waste heat from the engine, most electric vehicles today rely on direct resistive heating by electric heaters to heat cabin and traction battery in wintertime. This extra load on the drive train battery in cold temperatures can reduce the cruising range of a fully charged electric vehicle by up to half. In summer as well, the cruising range is shortened by the additional energy required for cooling the drive train battery and the interior of the vehicle. For these reasons, Mahle has  developed a compact system based on a heatpump (Integrated Thermal System, ITS)

In field tests with a compact electric car, the supplier has demonstrated that its ITS reduces the loss of cruising range substantially, especially at cold ambient temperatures. The original vehicle used, equipped with conventional electric heating, started with a cruising range of 100 km. When the vehicle was equipped with the ITS, the cruising range increased to 116 km.

The ITS combines various thermal components into one system that functions in several modes. Central to its architecture is a semi-hermetic refrigerant circuit, comprising a chiller, a coolant-cooled condenser (i-condenser), a thermal expansion valve, and an electric drive compressor. The icondenser and the chiller have the same function as the condenser and evaporator in a conventional refrigerant circuit. In this case, however, instead of exchanging heat with air, the refrigerant exchanges heat with the coolant, thus generating hot and cold coolant flows. The system uses R1234yf as a refrigerant and the conventional vehicle coolant as the medium for heat transport between the cooling circuit and the various heat sources and sinks in the vehicle.