Oak Ridge researchers achieve wireless charging with 96% efficiency

A team of researchers at Oak Ridge National Laboratory (ORNL) has used a patented multiphase electromagnetic coupling coil to wirelessly charge an electric car with an output of 100 kW and an efficiency of 96 per cent.

ORNL claims to have achieved “the world’s highest power density for a wireless charging system for this class of vehicle,” and achieved the result on a Hyundai Kona EV. The setup of the wireless charging system placed the charging mat about five inches away from the vehicle, over which the 100 kW charge was transferred via electromagnetic fields.

This is not the first time the research team succeeded in higher capacity wireless charging efforts, having managed a 120 kW charge using conventional coil technology in benchtop lab testing, however, this milestone is particularly meaningful as it shows that the ORNL’s polyphase electromagnetic coupling coil is functional. According to the research lab, “The polyphase electromagnetic coupling coil’s lightweight and small design allows for the highest power density within the smallest coils possible. Rotating magnetic fields generated by the coil phase windings boost the power.”

“We’ve achieved the highest power density in the world for a wireless charging system for this class of vehicle,” said ORNL’s Omer Onar. “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. This is a breakthrough achievement and opens the door to fast and efficient wireless charging for passenger electric vehicles.”

The ORNL also works in the area of battery research, for example, announcing a battery coating research project last year, followed by a lithium sourcing initiative. Closer to its current research focus, the ORNL also announced a bi-directional charging project in 2020.

ornl.gov