Oak Ridge National Lab Demonstrates 20-kW Wireless Charging

Wireless charging for EVs has been in the works for a while now, and a demonstration done last week at the Oak Ridge National Laboratory (ORNL) shows just how close it is to being ready for the market.

During the demonstration, a 20-kilowatt wireless charging system achieved 90-percent efficiency while charging at three times the rate of a standard plug-in charger. said ORNL.

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As the tech becomes better, it’s believed this could help spur adaption of EVs.

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The ORNL partnered with Toyota, Cisco Systems, Evatran, and the Clemson University International Center for Automotive Research.

“We have made tremendous progress from the lab proof-of-concept experiments a few years ago,” said Madhu Chinthavali, ORNL Power Electronics Team chief. “We have set a path forward that started with solid engineering, design, scale-up and integration into several Toyota vehicles. We now have a technology that is moving closer to being ready for the market.”

The wireless charging system includes an inverter and isolation transformer, and it took less than three years to develop. The demonstration vehicle was an electric-motor powered Toyota RAV4 with an additional 10-kilowatt hour battery.

Next up is a 50-kilowatt charging target. That would put the wireless chargers on par with current commercial plug-in chargers. Not only could faster charging times increase consumer acceptance/demand for EVs, but it will be a key component of electric-powered autonomous vehicles, and it’s needed for larger vehicles like trucks and buses.

Personal safety has also been taken into account by the researchers.

“The high-frequency magnetic fields employed in power transfer across a large air gap are focused and shielded,” Chinthavali said. “This means that magnetic fringe fields decrease rapidly to levels well below limits set by international standards, including inside the vehicle, to ensure personal safety.”

In addition to motionless charging, ORNL is also working on dynamic charging, which would allow a vehicle to charge wirelessly while in motion. Minimizing on-board complexity is also a goal.

Funding came from the Energy Efficiency and Renewable Energy’s Vehicle Technologies Office, as part the Department of Energy’s EV Everywhere Grand Challenge, which is attempting to make EVs on par with current gasoline-powered vehicles in terms of affordability and cost of ownership, with a target date of 2022.

“Wireless power transfer is a paradigm shift in electric vehicle charging that offers the consumer an autonomous, safe, efficient and convenient option to plug-in charging,” said David Smith, Vehicle Systems Program Manager. “The technology demonstrated today is a stepping stone toward electrified roadways where vehicles could charge on the go.”

In addition to several RAV4s, Toyota also provided a Prius plug-in hybrid and a Scion (it’s unclear what model, and all current Scions are gas-powered).