Researchers at Oak Ridge National Laboratory (ORNL), part of the US Department of Energy, have successfully demonstrated a 270-kilowatt (kW) wireless power transfer to a light-duty electric vehicle (EV).
The milestone was achieved using a Porsche Taycan and was conducted in collaboration with Volkswagen Group of America. This demonstration marks a significant breakthrough in the field of fast wireless charging for electric vehicles (EVs).
The 270-kW wireless charging system, developed by ORNL, uses lightweight polyphase electromagnetic coupling coils to achieve high power density in a compact form. The system’s innovative design enables the transfer of substantial power using rotating magnetic fields, which are generated by coil phase windings. It was shown that the Taycan could receive 50% charge wirelessly in 10 minutes.
This breakthrough builds on ORNL’s previous success with a 100-kW wireless charging demonstration and showcases the potential for even faster wireless charging solutions.
Lee Slezak, technology manager for grid and charging infrastructures at the Department of Energy’s (DOE) Vehicle Technologies Office, praised the achievement, stating that these recent advancements will accelerate the adoption of electric vehicles in the US.
The Porsche Taycan, a light-duty passenger vehicle, presents challenges for conventional wireless charging systems due to space, weight, and volume limitations. Current industry wireless charging standards for light-duty vehicles typically max out at 20 kW, while systems under development aim for up to 11 kW of power with approximately 92% efficiency. ORNL’s system, however, significantly surpasses these limits by delivering 270 kW with more than 95% efficiency.
The wireless charging system’s lightweight polyphase coils, which measure just over 19 inches in diameter, were seamlessly integrated into the undercarriage of the vehicle.
The system also includes safety features to prevent overheating, short-circuiting, and voltage surges. In the event of a power interruption, the system can initiate automatic shutdown procedures to ensure safe power transfer.
The 270-kW power transfer was conducted over a gap of 4.75 inches between the ground and the coil mounted to the vehicle. This setup achieved a 50% increase in the Porsche’s state of charge within just 10 minutes. Omer Onar, ORNL’s lead researcher on the project, noted that the system’s power density is 8 to 10 times higher than existing systems, making it the most lightweight and efficient charging solution of its kind.
The 270-kW demonstration concludes a DOE-funded project that began in 2021. Volkswagen Group of America contributed its expertise in vehicle integration, helping to develop the highest-power density wireless charging system for EVs. The system’s rotating electromagnetic fields reduce voltage fluctuations and eliminate electric current ripples, further improving efficiency.
Volkswagen’s chief engineering officer, Lyndon Lie, emphasized the importance of wireless charging in making EVs more convenient for consumers. By reducing charging times and simplifying the process, these technologies could accelerate the transition to zero-emission vehicles and a more sustainable transportation sector.
ORNL and Volkswagen plan to continue collaborating on refining the 270-kW prototype into a more cost-effective and manufacturable system. Additionally, the teams are exploring polyphase systems for residential charging and developing a lightweight enclosure design to enhance mechanical and thermal performance.
This achievement is part of ORNL’s ongoing efforts to push the boundaries of wireless charging technology. In 2016, ORNL successfully transferred 20 kW to a sports utility vehicle, followed by a 120-kW transfer in 2018 using conventional coils. The current demonstrations are the first to test ORNL’s polyphase system on electric vehicles.
Future work at ORNL aims to increase wireless charge rates for a wider range of vehicles, including heavy-duty trucks, to further expand EV adoption.
Researchers are also investigating wireless charging technologies for vehicles in motion, bringing the possibility of recharging on the go one step closer to reality.
