Experimental wireless EV charger is just as fast as a superfast wired plug, scientists say

A new type of wireless charging system can power electric vehicle (EV) batteries up to 10 times faster than the fastest available wireless chargers, and it's just as efficient as charging your car with a superfast cable.

Scientists at the Oak Ridge National Laboratory in Tennessee used a "polyphase electromagnetic coupling coil" with rotating magnetic fields to wirelessly charge a Hyundai Kona EV, which has an estimated range of about 261 miles, at 100 kilowatts with 96% efficiency, according to a statement released March 12. 

For reference, the fastest EV charging cables provide between 50 kW and 350 kW in power, while the ones that plug into a home wall socket have a power output of 1 kW, according to the Department of Transportation.

They used their prototype charging device, which has a diameter of 14 inches (36 centimeters), to transfer power to the EV across a 5-inch (13 cm) air gap.

The goal of research like this is to integrate wireless charging devices into the road — in parking spots, for example. That way, drivers no longer need to plug their cars into dedicated charging infrastructure with bulky cables.

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"We've achieved the highest power density in the world for a wireless charging system for this class of vehicle," Omer Onar, a researcher at ORNL who was involved in the work, said in the statement. "Our technology reaches power densities 8-10 times higher than conventional coil technology and can increase battery charge state by 50% in under 20 minutes."