WV & ORNL Achieve 270-kW Wireless Charging Breakthrough for EVsWV & ORNL Achieve 270-kW Wireless Charging Breakthrough for EVs

Wireless power transfer technology is a great option to charge electric vehicles (EVs), eliminating the need for cumbersome cables and providing a seamless charging experience. This cutting-edge technology harnesses electromagnetic fields to transmit power wirelessly from a charging pad to the vehicle's battery. As the EV market expands, innovations in wireless charging are becoming increasingly crucial for enhancing convenience, efficiency, and adoption rates. One such groundbreaking advancement comes from Oak Ridge National Laboratory (ORNL), setting new benchmarks in the field.

ORNL researchers have successfully demonstrated a 270-kilowatt (kW) wireless power transfer to a light-duty electric vehicle using a Porsche Taycan. The milestone marks a significant leap forward from ORNL’s previous 100-kW wireless charging demonstration and underscores the potential for fast, efficient wireless charging solutions for EVs.

A collaborative effort

The demonstration was a collaborative effort between ORNL and Volkswagen Group of America, leveraging ORNL's unique polyphase wireless charging technology. This innovative technology utilizes lightweight polyphase electromagnetic coupling coils critical in addressing the space, weight, and volume limitations inherent to light-duty passenger vehicles like the Porsche Taycan.

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“The receiver coil designed for the Porsche Taycan research vehicle can achieve 8 to 10 times higher power density compared to existing systems,” stated 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.”

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

How does the polyphase system technology work?

The polyphase system developed by ORNL operates similarly to the wireless charging mechanisms used for small consumer devices. According to ORNL, the polyphase system technology utilizes lightweight electromagnetic coupling coils with a diameter of just over 19 inches; the system is designed to achieve high power density within a compact form factor, making it ideal for light-duty vehicles like the Porsche Taycan.

The core of this technology lies in its ability to generate rotating magnetic fields through polyphase coil windings, which efficiently transfer extremely high power levels. This innovative approach reduces issues such as voltage ripples and field cancellations, significantly enhancing power transfer efficiency to over 95%. The system maintains this efficiency even with a 4.75-inch gap between the ground-based transmitter coil and the vehicle's receiver coil. ORNL also states that the new system can achieve a 50% increase in state of charge within 10 minutes with more than 95% efficiency. Also, the power transfer was conducted over a 4.75-inch gap between the ground and the coil mounted to the vehicle's underside. To learn more about this technology watch this short video.

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Safety and reliability

Ensuring safety and reliability, the technology incorporates advanced safety mechanisms to prevent overheating, short-circuiting, and exceeding voltage and current limits, providing reliable and safe operation. The polyphase system's breakthrough in delivering 270 kW wirelessly marks a significant leap from existing wireless charging capabilities, typically limited to 20 kW, and sets a new standard for fast, efficient, and compact wireless charging solutions in the electric vehicle industry.

Future applications

Looking ahead, ORNL researchers aim for even higher charge rates, particularly for heavy-duty freight and transport trucks. According to ORNL, achieving these higher charge rates will be pivotal in promoting the broader adoption of EVs by enhancing the range and simplifying the charging process—an essential development for daily commuters and light-duty passenger vehicles.

Onar said ORNL and Volkswagen plan to continue working together in the near term to further improve upon the 270-kW charging prototype by developing it into a more cost-effective and manufacturable system. “We’re also working with Volkswagen on developing a polyphase system for residential charging applications and collaborating on the development of a lightweight enclosure design that will improve mechanical, electrical, thermal, and magnetic performance,” Onar concluded, “Our goal is to mature the technology so that it’s ready for deployment in production vehicles.”

Supporting DOE’s vision

This latest achievement is a critical component of the Department of Energy’s (DOE) extreme fast-charging goal, which aims to develop systems capable of delivering 250 to 300 kW to electric vehicles, reducing charging times to 15 minutes or less. The research and demonstrations conducted by ORNL, supported by DOE’s Vehicle Technologies Office and the Office of Energy Efficiency and Renewable Energy, represent significant steps towards realizing this vision. With continued innovation and collaborative efforts, the future of EV charging promises to be faster, more efficient, and increasingly user-friendly, paving the way for a more sustainable and electrified transportation sector.