Managing Heat to Improve EV Efficiency
Effectively managing heat is one of the keys to making electric cars more efficient. Because electric motors have so few moving parts, they don’t generate nearly the same amount of residual heat as gasoline engines – heat that ICE cars use to warm their cabins and run other systems. Batteries also have an ideal operating temperature where they deliver the best performance and range – so ensuring they don’t get too hot, or too cold, is also important. In order to do these things, the heating and cooling systems in EVs have to work a lot harder than they do in gasoline cars – and they directly draw power from the battery.
An EV’s overall efficiency, and thus its range, is largely dependent on the efficiency of its heating and cooling systems. At a recent event in Korea, Hyundai and Kia showcased three technologies to effectively control temperature, save energy, and improve efficiency: nano cooling films, radiant heating systems, and metal-coated heated glass.
Nano Cooling Film Reduces Interior Temperatures
Nano-material technologies, which Hyundai and Kia have been experimenting with since 2023, can significantly lower an electric vehicle’s interior temperature, putting less strain on its air conditioning system, thereby improving its efficiency and increasing its range.
Acting like traditional tinting films, Nano cooling films block infrared radiation from outside the vehicle. Unlike traditional tints, they also allow heat to escape from inside the vehicle. Three layers of material include two layers that reflect solar energy and one layer that emits mid-infrared light.
During testing of models from both companies, nano cooling film was applied to glass surfaces. The nearly-invisible clear coating demonstrated a maximum temperature reduction of 12.5 degrees Celsius, or 54 Fahrenheit, inside the vehicle, dropping average temperature from 48.5 Celsius/119 Fahrenheit to 36 Celsius/96.8 Fahrenheit with no other changes.
Nano cooling films can even be layered with traditional tints in order to have a further cooling effect. Indeed, when fitted to around 70 vehicles in super-hot Pakistan, where tinting is legally prohibited, the films generated positive responses from drivers and passengers across the board.
Underfloor Radiant Heating Warms Up Interiors Quickly
While nano cooling films minimize the effect of hot weather on EV efficiency, underfloor radiant heating can help EVs perform much more efficiently and go much further in the winter. Similar to the systems used in some homes and commercial buildings, radiant heating systems use heating elements in the floor of the car, emitting radiant heat towards driver and passenger legs, helping the cabin warm up quickly in cold weather. Hyundai and Kia claim that the lower body feels warm within three minutes, greatly enhancing comfort.
A high-temperature film-type heating element can reach temperatures of up to 110 degrees Celsius, or 230 degrees Fahrenheit. The element is wrapped in a fabric material that emits infra-red rays, and can adjust the heat to a comfortable level. A burn prevention system is able to automatically detect contact, immediately lowering the temperature and reducing burn risk. On a vehicle like the Kia EV9, radiant heating panels can be installed on the steering column base, driver’s door and center console, and passenger door and glove box base.
Working alongside a vehicle’s existing heater, the radiant heating system is said to conserve up to 17 percent of the energy required to reach a desired cabin temperature, as well as reducing the amount of time it takes to warm the cabin. As such, these systems could significantly extend the range of EVs in the winter, by reducing the electricity used for the climate control system.
Metal-Coated Heated Glass Defrosts Quickly and Efficiently
Another glass treatment, metal-coated heated glass, evolves the heated windshields offered in some luxury vehicles to the next level – enabling electric cars to quickly remove frost and moisture from the glass during winter. Visibility is improved, and the metal coating is much safer than traditional embedded tungsten-wire heating elements. There are also no visible wires, meaning that metal-coated glass provides clear, undistorted view out.
Using the 48-volt electrical system in vehicles like the Hyundai Ioniq 5 and Ioniq 6, a metal-coated heated windshield can completely defrost the glass surface within just five minutes at temperatures below -18 degrees Celsius, or 0 Fahrenheit – about four times faster than a conventional heating system, and also using less energy in the process. Even better, on hot days, the metal coating also passively blocks 60 percent of solar energy, acting similar to nano-coating by reducing cooling requirements in the summer.
Conclusion: The Future of Heat Management Tech
As the push to make electric cars more efficient continues, the need to control both hot and cold temperature extremes will increase. Plus, drivers and passengers will continue to demand higher standards of comfort in their vehicles, no matter where they are or what they drive.
Technologies like nano cooling films, radiant heating, and metal-coated glass not only improve interior comfort, but they save energy, helping EVs manage energy better. In the coming years, Hyundai and Kia say that we should expect all three technologies on production vehicles we can purchase from dealer showrooms.
