The US Department of Energy’s Oak Ridge National Laboratory (ORNL) has licensed its high-power wireless charging technology for electric vehicles to HEVO. The system provides the world’s highest power levels in the smallest package and could one day enable electric vehicles to be charged as they are driven at highway speeds.

ORNL has licensed its high-powered wireless vehicle charging technology to HEVO, including the lab’s unique, compact polyphase electromagnetic coils that provide the highest surface power density available. Credit: Carlos Jones/ORNL, US Dept. of Energy.

The license covers ORNL’s unique polyphase electromagnetic coil that delivers the highest surface power density available, 1.5 megawatts (1,500 kilowatts) per square meter—eight to 10 times higher than currently available technology. This surface power density supports higher power levels in a thinner, lighter coil, resolving the issue of adding range-sapping weight to electric vehicles.

The license also includes ORNL’s Oak Ridge Converter, which eliminates one of the power conversion stages needed for wireless power transfer, resulting in more compact and less costly stationary infrastructure.

The ORNL technology enables very fast hands-free charging and even in-motion charging so vehicles could be reenergized as they’re driven at interstate speeds over specially equipped roadways.

Under the license, HEVO will work with ORNL to further develop the technology, including making it ready for commercial manufacturing.

In a recent announcement supporting deployment to the marketplace, Secretary of Energy Jennifer Granholm unveiled a DOE Technology Commercialization Fund award in which HEVO and ORNL will co-develop and demonstrate a 300-kW wireless charging system based on the ORNL converter and associated power electronics.

Together, we are developing the fastest and most universal wireless charging platform in the world. From only one device mounted on the vehicle, a driver will now have the advantage of wirelessly charging at all levels up to 300-kilowatts, powering their home through a vehicle-to-grid interface, and even charging while driving at highway speeds with grid-to-battery efficiency of 90-96.5%. All of this functionality is built into a vehicle-side package the size of a medium pizza box and the ready-made capability to charge electric vehicles without a human behind the steering wheel.

—Jeremy McCool, HEVO founder and CEO

DOE has set a goal to develop hands-free, automated wireless electric vehicle charging that is at least as fast as conventional refueling as it seeks to decarbonize the nation’s transportation sector. High-power charging also encourages buy-in by consumers concerned about driving range and the availability of charging infrastructure. In wireless charging, EV batteries are energized when vehicles are parked over a charging pad or driven over specially outfitted roadways while power is transferred across an air gap between magnetic coils embedded in the ground and installed on the car.

Most of today’s commercially available light-duty EVs have battery packs rated anywhere from 30 kWh to 60 kWh, and most of the higher end, longer range electric vehicles come with 100 kWh battery packs. Reaching a 15-20 minute charge time for a 100-kWh battery pack requires a 300-kW charging system. Targeting an even faster 5-10-minute charge time means power must be scaled up to half a megawatt or more. Heavy-duty vehicles like electric semitrucks would require battery packs with several hundred kWh energy storage capacity, which would require megawatt-level charging, ORNL researchers noted.

Opening up new parts of the transportation sector to electrification is a key benefit of this technology. It’s not just about charging your vehicle really fast. It’s also about being able to convert to electricity long-haul trucks, which burn a significant portion of the vehicle fuel used in this country.Burak Ozpineci, section head for Vehicle and Mobility Systems Research at ORNL

The dynamic charging system being developed at ORNL likewise supports electrification of heavy-duty trucks.

Right now, those big trucks would require massive battery packs that add significant weight and cost to the vehicle. But with dynamic wireless charging on interstates, for instance, you can reduce the onboard battery capacity needed while alleviating range anxiety.

—Veda Galigekere, who leads ORNL’s Electric Drives Research Group

The Oak Ridge Converter will be part of the TCF project and is included in the HEVO licensing agreement. It directly converts 60-hertz AC power from the grid to high-frequency AC without taking an intermediary conversion to DC power. The converter design reduces the weight, volume and size of stationary, grid-side infrastructure by as much as 50%.

ORNL also actively works on shielding technologies to ensure system safety and reduce interference with other vehicle components.

The ORNL research and development team also includes Erdem Asa, Gui-Jia Su and Mostak Mohammad. The work was supported by the DOE Office of Energy Efficiency and Renewable Energy’s Vehicle Technologies Office and the ORNL Laboratory-Directed Research and Development program. Researchers used capabilities of the Grid Research Integration and Deployment Center and the DOE-designated National Transportation Research Center user facility at ORNL.