A collaboration between the Department of Energy’s (DOE) Oak Ridge National Laboratory (ORNL) and Volkswagen Group of America resulted in the first 270-kilowatt (kW) wireless power transfer to a light-duty electric vehicle (EV), according to an ORNL press release. 

The breakthrough surpasses a recent ORNL demonstration of a 100-kW wireless charging, the release says. 

“In the past three months, the ORNL vehicle power electronics and electric drives research teams have set impressive world records for wireless charging,” said Lee Slezak, DOE’s Vehicle Technologies Office technology manager for grid and charging infrastructures, in the release. “These achievements will further speed up the adoption of electric vehicles in the U.S.”

Current industry standards cover up to 20-kW power levels, the release says. Wireless charging systems for light-duty vehicles are currently under development for up to 11-kW power with 92% efficiency, it says. Its release doesn’t say where the wireless charging systems are under development. 

ORNL first achieved 20 kW in wireless charging during a demonstration on a sports utility vehicle in 2016, the release says. It first achieved 120 kW using coil technology in 2018. 

“This achievement gets us one step further to the reality of a future where an electric vehicle can pull into a charging station and recharge in the same time it would take to walk into a store and grab a snack,” said ORNL’s Burak Ozpineci, corporate fellow and distinguished researcher who leads vehicle and mobility systems research. “The driver doesn’t have to do anything but park. We’re even exploring ways that this technology could be used to charge a vehicle in motion on the roadway.”

DOE has a goal to develop a system that delivers 250-300 kW to EVs with a reduced charging time of 15 minutes or less, the release says. 

The recent 270-kW demonstration was conducted on a Porsche Taycan, which is difficult to equip with conventional large, heavy wireless power transfer systems, the release says. It says the vehicle has weight, space, and volume limitations. 

“The ORNL-invented system that transferred power to the Porsche uses lightweight polyphase electromagnetic coupling coils with a diameter just over 19 inches that allow for higher power density in the smallest coil possible,” the release says. “This process is similar to the wireless charging of small consumer devices, but the unique geometry and design of the polyphase coils enable the transfer of extremely high power levels using rotating magnetic fields generated by the coil phase windings to boost the power.”

ORNL says the charging system was integrated into the undercarriage of the vehicle. 

“The receiver coil designed for the Porsche Taycan research vehicle can achieve 8 to 10 times higher power density compared to existing systems,” said ORNL’s Omer Onar, leader of the Vehicle Power Electronics group and lead researcher on the Porsche demonstration. “Per kilowatt weight, this is also the most lightweight charging system in the world.”

Power density indicates how much power the system can handle relative to its size, the release states. 

“The goal is to achieve higher densities from smaller, more compact systems to improve overall efficiency and performance,” the release says. “ORNL’s system can achieve a 50% increase in state of charge within 10 minutes with more than 95% efficiency.”

The power transfer was conducted over a 4.75-inch gap between the ground and the coil mounted to the underside of the vehicle, the release said. 

ORNL also uses a protection system in its technology to prevent exceeding voltage and current levels, overheating, and short-circuiting, the release says. The system will shut down procedures if it determines there is a power interruption or any other unexpected conditions that could interfere with a safe power transfer. 

“It’s exciting to see the significant progress Volkswagen and Oak Ridge National Lab are making together in many critical technologies. Innovation projects being researched in East Tennessee will transform the automotive industry,” said Lyndon Lie, Volkswagen Group of America’s chief engineering officer, in the release. “Wireless charging like that demonstrated with Oak Ridge could make charging EVs significantly easier for consumers, with quick charging times encouraging zero emissions adoption and leading to a more sustainable transportation sector.”

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ORNL researchers collaborated with Volkswagen Group of America to demonstrate the wireless 270-kW power transfer to a Porsche Taycan. Photo courtesy of Carlos Jones/ORNL, U.S. Dept. of Energy