Hands-Free: Wireless Charging System Advances Electric Vehicle Convenience

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Source: ORNL, https://www.ornl.gov/sites/default/files/2021-05/2021-P03094_0.jpg
Source: ORNL, https://www.ornl.gov/sites/default/files/2021-05/2021-P03094_0.jpg

June 2, 2021 | Originally published by Oak Ridge National Laboratory on May 18, 2021

Consumer buy-in is key to the future of a decarbonized transportation sector in which electric vehicles largely replace today’s conventionally fueled cars and trucks. Oak Ridge National Laboratory scientists have for several years now steadily advanced a wireless charging technology that can make powering an EV just as easy, or easier, than filling up a car with gas. The researchers are now nearing the completion of a new system to charge EVs while they’re in motion.

Electrifying transportation is at the top of the list for solutions to decarbonize the American economy. The transportation sector is the largest source of greenhouse gases in the nation, with cars and light trucks alone accounting for 60% of emissions. The Department of Energy has supported a range of research to make EV ownership more convenient and less costly for consumers, including the goal of a 15-minute or less charge time.

With custom magnetic coils, silicon carbide-based power electronics, and novel controls and shielding technology to handle stray emissions, ORNL scientists have proven that their system can wirelessly charge both a light-duty passenger car across a six-inch airgap and a medium-duty delivery truck across an 11-inch airgap at the 20-kilowatt level at greater than 92% power transfer efficiency — on par with a wired system. Power can even flow in both directions, enabling vehicles to serve as energy storage.

The researchers have successfully demonstrated a 120-kW wireless charging system with 97% efficiency, and are planning to install higher voltage systems, up to 270-kW, on passenger vehicles to meet or exceed the 15-minute charging goal.

The research is supported by the DOE Office of Energy Efficiency and Renewable Energy’s Vehicle Technologies Office. The systems are built and evaluated at the National Transportation Research Center at ORNL, the only DOE-designated user facility focused on performing early-stage research and development in transportation technologies. The medium-duty vehicle wireless charging demonstration was held at the new Grid Research Integration and Deployment Center, or GRID-C, at ORNL, which combines multiple electrification research across the vehicle, buildings, and grid space.

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