Why Do Cold Temperatures Affect Batteries?
Lithium-ion batteries operate on chemical reactions and the movement of lithium ions in an electrolyte. As the temperature drops, chemical reactions slow down and the electrolyte becomes more viscous. This increases the internal resistance of the battery, temporarily reducing its usable capacity and restricting regenerative braking.
The second major factor in winter range reduction is heating. Unlike an ICE car, which uses waste heat from the engine, an EV has to generate cabin heat using energy from the traction battery.
How Much Does a Heat Pump Help?
Traditional resistive heating (PTC) has a heating coefficient (COP) of 1, meaning that it generates 1 kW of heat from 1 kW of electricity. Modern heat pumps can operate with a COP of 2 to 3 – by compressing refrigerant, they extract heat from the outside air and from the powertrain components.
Thanks to a heat pump, you can save 50% to 70% of the energy needed for cabin heating. In terms of real-world winter range, this translates to saving approximately 10% to 15% of the total battery capacity. A heat pump is most beneficial for frequent short trips and urban driving.
Tips for Operating an EV in Winter
Precondition on the Charger: Use the car's mobile app to heat the cabin and battery while the car is plugged in. The heating energy will come from the grid, not the battery.
Use Heated Seats and Steering Wheel: These elements warm your body directly and consume only about 100-200 W, whereas forced-air heating consumes 2 to 5 kW. If you are driving alone, turn down the cabin heater and use the seat heater instead.
Plan Charging at the End of a Trip: The battery is warm after driving, so it will immediately accept maximum charging power. A cold battery charges significantly slower (so-called coldgating).