- Heat management innovation maximises EV driving range in low temperatures
- Can heat cabin without significant impact on driving range
- Industry leading heat pump technology introduced with first generation Kia Soul EV in 2014
Hyundai Motor and Kia Motors have announced details of an innovative heat pump system used in both brands’ global electric vehicle (EV) range to maximise all electric driving range in low temperatures.
The heat pump maximises the distance EVs can travel on a single charge, scavenging waste heat to warm the cabin. It enables occupants to heat the cabin in cold weather without significantly impacting electric driving range, unlike other EVs.
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The technology was first introduced in 2014 on the first generation Kia Soul EV.
Comprising 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.
The technology meant the EV’s 180km (112 miles) electric range was protected in cold weather driving conditions.
The heat pump system has now been developed further for new EVs.
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By GlobalDataThe new system scavenges waste heat from an increased number of sources to improve cold weather EV range.
The automakers claim the innovations give their EVs offer more consistent range in temperatures where rivals start to see a significant decline in the distance attainable from a single charge.
Equipped with this technology, the Kona Electric proved this in a recent test in Norway, the most advanced EV market in the world, Hyundai said.
The Norwegian Automotive Federation (NAF) recently compared 20 EVs in cold and warm weather conditions to identify models with the most consistent driving range and charging performance. The test monitored the performance deviation of each vehicle in cold conditions compared to quoted manufacturer figures.
The Kona EV took first place, travelling 405km (252 miles) in the cold compared to 449km quoted under WLTP combined cycle testing conditions (23°C/73°F).
In severe cold weather, the Kona Electric achieved 91% of its WLTP combined cycle range, deviating just 9% from its claimed driving range.
This heat pump technology arrived six years ago in the first-generation Kia Soul EV. Subsequent development sees it now harvest significantly more energy by recycling additional waste heat not just 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 heat generated by these components to vaporise 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 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 minimise battery power consumption.
By reducing the load on the battery, the heat pump cuts energy consumption by the HVAC system, maximising the available electric driving range of the car.
The automaker plant to continue to develop the technology to yield even greater improvements in energy capture and efficiency.
The system has been gradually refined since its 2014 introduction through extreme cold weather testing in Northern Sweden where temperatures can get as low as -35C (-31F) in the winter.
By testing in extreme cold temperatures, research engineers have identified additional ways to recycle as much waste heat as possible to increase efficiency. Testing in these conditions ensures the heat pump is capable of operating in the coldest environments.
Other claimed innovations in current Hyundai group EVs include heat management also used to realise major improvements in the battery packs.
A water cooling system, rather than conventional air cooling, has yielded further increases in range without increasing physical dimensions.
This development means battery cells 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 has led to twice as much driving range and battery capacity compared to first generation EVs and the cars now can travel significantly further on a single charge.
The first generation Soul EV had range of around 180km (112 miles) on a single charge of its 30kWh lithium-ion polymer battery pack.
The second generation car, with a 64kWh battery occupying a similar amount of space, is capable of traveling up to 386km (240 miles).
A study carried out by Korea’s environment ministry 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 -7C (19F) with the HVAC system activated, they were able to maintain 90% of their driving range compared to journeys undertaken at 26C (79F), setting a new benchmark for other EVs.
By contrast, many EVs offered by rival automakers saw their total electric driving range drop by between 18% and 43% under the same test conditions.
Under its Strategy 2025 plan, Hyundai Motor aims to sell 670,000 battery EVs and FCEVs (fuel cell electric vehicles) annually and become a top three EV manufacturer by 2025.
Affiliate Kia’s mid- to long-term strategy, dubbed Plan S, will see the brand’s range grow to 11 EVs over the same timeframe.
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