At its introduction last summer in Barcelona, Spain, the 2019 Audi A8 quattro became the poster child of automotive high tech: matrix LEDs that shine from the headliner with the wave of a hand, advanced autonomous driver assistance sensors, active electromechanical suspension. And on the floor under one of the models, a gray metal pad.
Onlookers watched as the pad rose slightly, nearly touching a coil under the front axle. Forget the cables and cut the cords: This was how the prototype of the A8 L e-tron hybrid would send energy to its block of 104 battery cells.
Give thanks to Tesla — Nikola, the inventor, not the car company — who more than a century ago used electromagnetic energy to transfer power over an “air gap” between two coils. Wireless, or inductive, charging is the next frontier for hybrid and electric vehicles that one day will charge in much the way your new toothbrush or cellphone does. And farther down the road is the tantalizing possibility that cars in motion will be charged “dynamically,” on the street, by the street.
But induction charging is at least three years away from mass-market automotive application, said Jesse Schneider, who heads a wireless task force for the Society of Automotive Engineers. And, like most technological advances in this industry, a wireless power transfer standard — now in late-stage discussions by the SAE — will need to be approved as safe and secure by the federal government.
It will also require consensus among the world’s vehicle makers. In an industry where competition and proprietary technology are the norm, establishing a one-size-fits-all system is a tricky proposition. But Brian McKay, the North America director of powertrain technology and innovation for the automotive components supplier Continental, said most automakers had already accepted “a pretty well-defined standard to ensure interoperability.”
Schneider said he believed that wireless charging would help break down barriers for electronic vehicles by making it as simple as pulling into your usual parking spot and walking away. “There are 14 automakers and suppliers on my team, and we have a huge effort underway to come up with one standard methodology,” he said.
The limited real-world systems that employ wireless charging require precisely parking a receptor-equipped vehicle over a charging platform. Audi claims a charging efficiency of more than 90 percent, meaning that less than 10 percent of the power sent to the charger is lost in the process of topping off the battery. Fully charged, the car — which is not due in the United States until next year — is expected to be able to travel about 30 miles on electricity alone, Audi said.
Porsche is also planning to offer wireless charging on its all-electric Mission E sedan and crossover. BMW has announced a wireless charging option for its 530e hybrid. Similar options are expected for the electric Nissan Leaf and the Toyota Prius hybrid.
Automakers generally have shied away from revealing details of their plans for wireless charging. Mark Dahncke, a spokesman at Audi of America, said he had not yet seen the specifications of the United States-bound A8 e-tron. And a spokesman for Nissan had no comment on “future product plans.”
Even though “pure electric” cars account for a small fraction of sales in the United States, Schneider and other researchers are confident that consumers will eventually embrace wireless power transfer. They expect costs to decrease and point to government standards like California’s Zero Emission Vehicle program.
“It’s not the price of gasoline that’s driving the EV market,” Schneider said. “Now it’s more about government regulations and the environment.”
McKay of Continental said he was convinced that engines powered by gasoline would coexist with electrics for at least the next decade. But at the same time, he sees wireless charging technology becoming more cost-effective — and necessary to meet the emission requirements emerging around the world.
“Even though each vehicle is getting cleaner, there are just more of them,” he said. “We need to go to a more sustainable approach, which is more electrification in the future.”
In fact, a test focused on static power transfer carried out by Toshiba showed that replacing a diesel bus with a wirelessly charged electric bus — which benefits from centralized generation and renewable energy sources — could reduce carbon dioxide emissions by up to 60 percent.
Even as the automotive industry hurtles toward meeting more immediate challenges, a team of electrical engineering students at Stanford University has taken a decidedly more futuristic approach.
Under the direction of professor Shanhui Fan, they are among those who have envisioned dynamic charging of a vehicle — sending power to a moving car using transmitting devices either along the roadway or embedded in it.
So far, the Stanford researchers have been able to send consistent power to a moving light bulb.
The team’s vision is very much blue-sky, Fan allowed; he wouldn’t even guess a date for commercial real-world dynamic charging.
“We are in our labs pushing for higher power levels,” said Fan, who drives a Prius. “Maybe we can get a prototype going in a few years.”
His team is not the only one tackling the problem of charging on the move. The chipmaker Qualcomm has its Halo DEVC (dynamic electric vehicle charging) project, which involves a 100-meter test track erected in Versailles, near Paris. Induction chargers inlaid in the roadway allow a vehicle — in this case, an electric Renault Kangoo van — to power up as it passes over. The track’s cost was subsidized by the European Commission.
Schneider of the SAE said he was skeptical of on-the-fly charging. A proof of concept is one thing, but standardization is necessary.
“And why do you need it?” he asked. “Why do you need to tear up highways? Just because it sounds cool?” He added, “Before jumping to science fiction, well, a lot of things are possible.”
For him, one of the more relevant possibilities on the SAE’s task force agenda is not driving.
“A car sits for between 90 to 95 percent of its life,” Schneider said. “If you can take advantage of the time it doesn’t move with a wireless-equipped parking space at home, where the customer doesn’t have to plug in but just park, then it changes the whole dynamic of the electric vehicle.”