Hyundai and Kia introduce new heat pump technology for EV efficiency
Hyundai Motor Co. and Kia Motors Corp. have revealed details of their heat pump system deployed in Hyundai and Kia’s global electric vehicle (EV) line-up to maximize their all-electric driving range in low temperatures.
The heat pump is designed to maximize the distance that both automakers’ EVs can travel on a single charge, scavenging waste heat to warm the cabin. It enables drivers to heat their car’s cabin in cold weather without significantly impacting electric driving range.
The technology was first introduced in 2014 on the first-generation Kia Soul EV. Including a compressor, evaporator, and condenser, the heat pump captured waste heat given off by the vehicle’s electrical components, recycling this energy to heat the cabin more efficiently.
How it works: EV cabin heating without the energy drain
The heat pump technology has been developed further for new EVs from Hyundai and Kia. It now harvests significantly more energy by recycling additional waste heat not only from power electrics (PE) modules (such as drive motors, on-board chargers, and inverters), but also from the battery pack and slow charger.
The system uses the heat generated by these components to vaporize refrigerant from liquid to gas form. High-pressure gas is discharged from the compressor and forced into a condenser to be converted back into a liquid. This process generates additional heat energy that is recovered by the heat pump and used to warm the cabin.
This captured energy improves the efficiency of the HVAC (heating, ventilation, and air conditioning) system, recycling it to more efficiently heat up the cabin and minimize battery power consumption. By reducing the load on the battery, the heat pump cuts energy consumption from the HVAC system, maximizing the available electric driving range of the car.
Battery pack heat management enhances EV driving range
Heat management was also used to realize other improvements in EV battery packs.
A water-cooling system for the battery packs, rather than conventional air cooling, has yielded further increases in range without increasing physical dimensions. This development means battery cells in these vehicles can be packaged much more tightly, with water-cooling channels taking up less space than air-cooling channels, increasing battery density by up to 35%.
This means the latest EVs from the automakers reportedly offer around twice as much driving range and battery capacity compared to the their first-generation EVs and are capable of travelling significantly further on a single charge. For example, the first-generation Soul EV offered owners an electric driving range of around 111 mi (180 km) from a single charge of its 30 kW·h lithium-ion polymer battery pack. The second-generation Soul EV, with a 64 kW·h battery occupying a similar amount of space, is capable of traveling up to 240 mi (386 km) on a single charge.
A study carried out by Korea’s Ministry of the Environment on the Hyundai Kona Electric and Kia Niro EV found that the heat pump significantly reduced battery consumption in cold conditions. When each car was driven in temperatures of 19°F (-7°C) with the HVAC system activated, they were able to maintain 90% of their driving range compared to journeys undertaken at an ambient 79°F (26°C).
For more information, visit www.kia.com.