Japanese boffins demo EV on-the-move charging
Except it’s low-powered and inefficient
Electric vehicles have two problems: to make them “zero emission”, they need to be recharged from “clean” sources; and range remains a challenge. A Japanese proposal would, if it worked, address the second – but probably exacerbate the first.
A team from the Toyohashi University of Technology has demonstrated an electric field coupling system that they say would let cars be recharged on-the-go through their tyres.
This isn’t easy: the electricity has to be coupled across several inches, which amplifies the losses that take place in trying to get electricity transferred across a wireless channel. The Toyohashi demonstration showed that it was feasible to transfer between 50 and 60 watts through a four-inch concrete block, coupling to the tyres’ steel belts and powering a light bulb.
Efficiency is, however, treated optimistically by researchers in this field. Last year, similar research was hailed as a success since only 20 percent of the total energy was lost in the circuit.
Of course, if the vehicle isn't charged from a clean source, then 20 percent loss means you don't only move the emissions to wherever the power station is; each vehicle's emissions are that much worse than if you recharged with a cable.
Toyohashi University of Tech says the power transfer in its EVER (Electric Vehicle on Electrified Roadway) would have to be scaled up 100 times – transferring more like 5 kW than 50 W – to be useful. ®
They're thinking about this all wrong.
What you need is an insulated rod sticking out of the floorpan with a metal brush contact on each side. Then cut a slot into the middle of each lane of the motorway and lay metal tracks along either side of it. Wire these tracks in pairs to a high current DC supply. Lane changing can be facilitated by randomly placing slot crossovers - ideally just after a long, fast corner or humpback bridge. As an added bonus, traffic police can adjust the maximum speed on the road by using a handheld variable resistor wired into the DC supply.
The article derides the 80% efficiency as being too low to be practical.. the reality is that this is actually pretty good for a wireless system.Even with a wired system, you would be doing well to get 90% efficiency out of it. Less if you count the losses through the battery and charger (assuming the wireless system power is used dynamically rather than stored)
That said, yes its still more practical to recharge at stations.. the cost of implementing this on just motorways would be astronomical (anyone seen the price of copper cable these days?)
Re: Trains and Trams
Real live Skalektrix!!