Wireless charging the next big EV thing
BY MIKE COSTELLO | 5th May 2011
Laura Marlino, a research engineer at the world-renowned Oak Ridge National Laboratory in Tennessee, said at last month’s Automotive Power Electronics conference in Paris that the introduction of wireless charging was “not a matter of if but when”.
Wireless charging involves the transmission of power between two coils, one located in the car and the other in the charging device, which can be fixed into the ground or as part of a portable mat that can be deployed when needed. The driver just moves the car over the energy source to begin charging.
Marlino told the audience that this kind of convenience makes wireless charging the way of the future: “Think of a mother of three children coming back from her shopping with her arms full. It would not be surprising if she forgets to plug in her car,” she said.
Marlino, who is deputy director of Oak Ridge’s Power Electronics and Electric Machinery Research Centre, told those gathered at the conference that technology designed with car-makers and suppliers had been able to pass 5kW of charge across 254mm of air with more than 90 per cent efficiency.
This technology is not limited to the lab, however, with a company that runs shuttle buses at Boston’s Logan airport planning to embed inductive chargers into the spaces where the buses pick up passengers, so they can charge while they wait.
Wireless induction charging is on the agenda for the next-generation of electric vehicles, with Renault’s director of advanced electronics and technologies Patrick Bastard telling automotive analysts Wards that “(Wireless) induction would be a performance increase that we could offer. It could be a good, easy way of charging your car.”Renault’s global ally Nissan has been working on the technology for several years, with the company claiming to have conducted experiments on this method of recharging across Japan.
Last week, Toyota announced a forthcoming collaboration with WiTricity Corporation, an American company that specialises in wireless technology using resonance.
According to Toyota, resonance charging is more efficient than the traditional electromagnetic wireless induction seen in electronic devices such as mobile phones and even electric toothbrushes, which also require contact between the two energy sources.
Electronics supplier Delphi is currently developing its wireless EV charging device, also co-developed with WiTricity, which it installed into a Think EV test car in April this year.
A company release stated that these charging sources “can be buried in pavement, are unaffected by environmental factors such as snow, ice or rain, can accommodate a wide range of vehicle shapes and sizes and their differing ground clearances”.
At April’s Hannover technology show, BMW and Siemens also announced that they had teamed up for a project dubbed “Contactless Charging of Battery-Electric Vehicles” project, which will undergo prototype-stage testing in Berlin at the end of this year.
BMW-owned Rolls-Royce has also embraced wireless induction, displaying an EV Phantom 102EX with the technology at this year’s Geneva motor show.
The company said the wireless system charged with 90 per cent efficiency, did not have to be perfectly aligned with the transfer pad for it to work and that it was designed to shield bystanders from the electromagnetic energy.
Meanwhile, North American company eCoupled have fitted a Tesla Roadster with a wireless system that allows the car to be recharged in special car bays. The recharge costs can then be paid for via an iPhone app.
