Massachusetts-based startup WiTricity believes it has the answer to electric vehicle (EV) charging. But first, WiTricity vice president of sales and business development David Schatz has a torso to show me.
It’s the first time WiTrcity has shown its torso, which is really a gel mold that resembles human flesh. Inside it are lights that represent medical devices like heart pumps that could require 10 to 20 watts of power, neurostimulators needing few hundred milliwatts to a few watts, and implanted drug delivery pumps requiring anywhere from milliwatts to several watts. Instead of implanting batteries or having wires running out of a person, WiTricity says it can charge the in-body devices wirelessly, with its technology. Schatz places the torso on the table, holds a magnetic resonator device under the table, and the objects in the gel torso light up. Pretty cool.
What does this have to do with green tech and energy efficiency? The same can be done to wirelessly charge electric vehicles (EVs), consumer electronics devices, TVs, computers, you name it.
WiTricity is an OEM manufacturer of wireless charging systems that use magnetic resonance (actually “highly resonant magnetic coupling”). Some other wireless charging technologies use magnetic induction, a technology that has been around since the days of Nikola Tesla.
Magnetic resonance is the same principle that applies when the sound waves from a soprano shatters a glass. Only in this case it creates energy from the magnetic field, which WiTricity says is no more of a danger than the magnetic field we live in, created by the Earth.
Schatz shows how magnetic resonance can wirelessly charge an electric vehicle, with no plugs or wires, using a model. A 3.8-cm-thick resonator is positioned on the floor—or in the floor—of a garage, and a thin capture device that can be about 2-cm-thick is mounted in the vehicle, to charge the EV battery with up to 3.3 kilowatts (3,300 watts) of power, via the magnetic resonance transmitted at 145 KHz. Schatz says a plug-in hybrid electric vehicle (PHEV) using WiTricity technology could charge in two to three hours and an all-electric Nissan Leaf or Mitsubishi i-MiEV could take six to eight hours, or about the at the same rates as current Level 2 220-volt chargers. The range of the signal is about 10 to 20 cm.
Why go wireless? “Making it easier for people to plug in is pretty important,” says Schatz. A Toyota representative at the recent Babson Energy & Environmental Conference said an alarming number of Prius hybrid plug-in owners never plug their vehicles in, relying instead on the hybrid gas engines. (He said 90 percent, but I have not been able to confirm that number.) Toyota appears so disenchanted with EV charging issues, it is also testing out hydrogen fuel-cell vehicles and plans to launch a hydrogen-powered electric vehicle in 2015.
Schatz says Toyota has begun testing vehicles in Japan with wireless charging, and he expects we’ll be able to buy cars with wireless charging by 2016. Audi and Mitsubishi, are also developing electric vehicles utilizing WiTricity technology. WiTricity is looking at three stages of wireless charging markets, starting with residential, then moving into commercial fleets and then public infrastructure like parking lots. The signal can go through concrete and asphalt, the company says.
Magnetic resonance can be transmitted through and around objects at a greater distance than magnetic induction, leaving more room for placement error. Though the efficiency of the signal fades as distance grows.
Schatz says there is a lot of interest in using the 6.78-MHz signal with thin resonators using printed circuits.
WiTricity says even its basic electronic device chargers are green. The company claims up to 95 percent efficiency in the power transfer when the devices are near—and its test kit charging pads are smart enough to stop powering a device when it no longer requires a charge, Schatz says. This also precludes the needs for disposable batteries—a big green no-no—and rechargeable standalone batteries that are often troublesome to use.
WiTricity also shows a wireless TV, wireless office equipment and other devices, even a LeBron James athletic shoe with its sensor charged by a WiTricity device. “Big CE companies will bring wireless power transfer into their products,” Schatz says
WiTricity is also looking at industrial markets for devices like wireless sensors, actuators and robotics.
The company is eager to make its systems available, and won’t rule out marketing its own devices.
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