Slashdot Mirror
GM Partners With Boston Startup WiTricity To Develop Wireless Charging Technology (electrek.co)
Earlier this week, General Motors announced a partnership with Boston-area startup WiTricity to develop wireless charging pads for electric vehicles. Their goal is to develop a wireless "charging pad" that can be installed beneath a layer of concrete or other garage flooring material so that cars would simply need to be parked over the pad to automatically start charging. Electrek reports: "The electric vehicle has been recognized as central to the future of mobility, and GM has been a leader, making EVs accessible to the broader market. The convenience of wireless charging will help accelerate adoption even further," said Alex Gruzen, CEO of WiTricity, about the alliance. "Wireless charging for EVs, based on industry standards, is inevitable as we move toward a future of self-driving and autonomous vehicles, and this project brings us one step closer to realizing our vision of a world powered wirelessly." GM agreed to allow WiTricity to conduct tests on a Chevrolet Volt hybrid vehicle, "to show how well it would work integrated into a real car," according to Gruzen. Witricity claims that their system can achieve over 90% efficiency, which would make it at least as efficient as a plug-in charger. "Wireless charging is a technology that our customers have told us they are interested in," GM's executive chief engineer of electrified vehicles, Pamela Fletcher, said. "By testing the WiTricity prototype system, we can ensure that wireless charging systems will comply with proposed industry standards, which benefits the entire industry and consumers." The company has high hopes for their product. Gruzen envisions a future in which EV owners can send autonomous cars to charging stations remotely, a future that would only be possible with wireless charging stations.
It's not exactly just the gap that creates inefficient coupling but the ratio of the area of the field to the gap. Therefore on a car where the field is coupled across nearly the whole width the gap can be somewhat large compared to a phone and still not be too bad.
There are other gotchas though such as what if stray pieces of conductive material get in the way? If the vehicle is going to actually charge at a reasonable rate then some stray piece of metal can be a real problem in terms of picking up energy and heating. You could carefully monitor the power on both sides but it's hard to say if the difference is going to heat something. Another is broadcasting all kinds of errant emissions. When you broadcast that much power even little screwups like not parking in the exact right spot or minor damage to the bottom of the car could create tons of unwanted noise at all kinds of frequencies.
While it sounds cool to wirelessly charge, in reality it's likely to be far more practical and inexpensive to just use a plug.