Imagine that after a long day on the road, you drive your new electric car into your garage, the battery almost drained. But you don’t worry about running a cord to the charging station and plugging into your vehicle—the garage takes care of recharging for you, without you doing a thing. When you leave for work the next morning, there is no charging cord to stow—and therefore no danger you’ll back out of the garage without having remembered to detach it (average bill a few grand for damage to the power unit and your car). You just hit the road again fully charged.
That’s the vision Eric Giler, CEO of Watertown, MA-based WiTricity, will be demonstrating this morning (Boston time) at the First German Electric Vehicle Congress in Bonn, Germany. WiTricity is a 19-month-old MIT spinout that has sparked the imaginations of people around the world with demonstrations of firing up laptop computers and charging cell phones through wireless delivery of power. (For company funding, employee count, patent filings, and other stats see fact box on the last page of this article.) But tomorrow morning, Giler will be presenting his vision of what could become a second major market for WiTricity, after consumer electronics: charging electric vehicles.
“You spend $100,000 on a car, and you have a cord to plug it in,” says Giler a bit disdainfully, speaking of the main electric vehicle on the road today, the Tesla Roadster, which starts at $101,500. “[But] imagine if you can just drive in your garage and your car charges—that’s what we’re doing now.”
Giler will be on stage today demonstrating two configurations for how the electric vehicle charging station of the future might look. One is where you drive into a garage and your car is charged from underneath, via something like a mat on the floor. The other is a wall mounted or upright charging station, where you tool up to the unit and power is transferred between it and the car’s bumper.
Whichever one wins out, and maybe both will, WiTricity calls electric vehicles (EVs) a “zero-billion-dollar market”—meaning sales are essentially nothing right now, but as prices come down and competitors like the planned Chevy Volt and other mass market vehicles hit the road, the market will be huge. And, the company figures, since all EVs will have to charge up in some manner, there should also be a big opportunity awaiting WiTricity’s elegant, easy-to-use solution.
Some quick background here. WiTricity is the fruit of a discovery a few years back by MIT assistant professor of physics Marin Soljačić, who, after being awakened by a cell phone beeping in the night because no one had charged it, realized he might avoid that problem forever if he could find a way to tap wirelessly into the wired electric power already flowing throughout his house and have it charge the cell phone for him.
His answer depends on what’s called highly resonant magnetic coupling. Basically, a specially designed coil (WiTricity’s transmission unit) is connected to a small electronics module that converts the normal 60-cycle alternating current that you’d find in your home or office to a higher frequency and voltage—inducing an oscillating magnetic field around the coil. If a different coil designed to resonate to the same frequency is near enough to the source, power is transferred between the two coils (think opera singer shattering a glass). There’s a lot more to it, of course, which you can read all about here. Soljačić won a MacArthur genius award for the invention last fall.
Chances are you have already heard of this story, as Soljačić and WiTricity have been written up from the New York Times to Scientific American to Sueddeutsche Zeitung. Giler says the technology works from distances of a few centimeters to a few meters and at power levels from a few milliwatts to several kilowatts—and that it is completely safe for people and animals, producing magnetic fields under the limits set by the FCC and in other guidelines. “Safe, efficient power transmission over distance,” is a company mantra.
But let’s steer the conversation away from basic physics back to the electric car, which is the really new thing for WiTricity—and which Giler says hasn’t been publicized before. He revealed
