A Stanford research team is looking to a future populated with vastly more electric powered cars, and is hoping to tackle a current drawback in plug-in electric cars—range. However, instead of focusing on car batteries, the team has decided that the actual highways hold the answer, and are researching a new charge-as-you-drive system to overcome range limitations.
Stanford’s Global Climate and Energy Project (GCEP) is funding the research that hopes to solve the range anxiety surrounding all-electric cars. An example is the Nissan Leaf, which gets close to 100 miles per charge, and once depleted, takes many hours to recharge. The team hopes to implement a wireless charging system embedded in the road which would charge an electric car as it drives over source coils. Though the researchers have only recently filed a patent application for the wireless system and have yet to see their data in real driving conditions, the vision for the project extends quite far.
“Our vision is that you’ll be able to drive onto any highway and charge your car,” said associate professor of electrical engineering, Shanui Fan. “Large-scale deployment would involve revamping the entire highway system and could even have applications beyond transportation.”
If implemented on a large-scale, a driver could potentially drive for an unlimited amount of time; stopping only for maintenance and human recharging. Fan and his team are building their research off of MIT researchers’ work with a WiTricity spinoff company. The WiTricity work produced a stationary charging system that could transfer 3 kilowatts of power wirelessly over mid-range distances, like from a house to a car on the street.
Stanford’s modification of the MIT system hopes to produce 10 kilowatts of electrical power that can be transferred to a car 6.5 feet away. The Stanford system design will implant an array of current connected coils, bent at a 90-degree angle, within a highway. A car will have a receiving coil attached to the bottom and would resonate as the car travels down the highway, creating a magnetic field that transfers electricity and keeps the vehicle moving steadily down the road. According to computer simulations of the system, the wireless transfer idea has an efficiency of 97 percent.
As the research is still in its initial stages, the team has yet to test the ideas in a laboratory, or real driving conditions. Shanhui Fan points out that the wireless power won’t affect objects which are tuned at different frequencies; power transfer will only occur if resonators are in tune. Also, the MIT work has already demonstrated that the magnetic field will not affect people who stand between the two coils. However, the Stanford team wants to be absolutely certain no harm could happen to any car passengers.
“We need to determine very early on that no harm is done to people, animals, the electronics of the car or to credit cards in your wallet,” said executive director for Stanford’s Center for Automotive research, Sven Beiker. Though 97 percent energy transfer is reported, Beiker and others want to make sure that the remaining percent of energy does not end up as potentially harmful radiation.
The team believes the revolutionary power transfer vision could change the way we power everything; it could also be the bedrock for an accident reducing, greenhouse gas emission lowering, automated highway system.