Gov't Researchers Develop Wireless Car Chargers That Are Faster Than Plug-ins (computerworld.com)

An anonymous reader quotes a report from Computerworld: The U.S. Department of Energy has demonstrated a 20,000 watt (20KW) wireless car-charging system that offers three times the efficiency of today's plug-in systems for electric vehicles (EVs). The research is the first step in creating a 50KW wireless charging system that may someday allow roadways to charge vehicles while they are being driven. The DOE's Oak Ridge National Laboratory (ORNL) in Tennessee demonstrated the new system in partnership with Toyota, Cisco Systems, Evatran and the Clemson University International Center for Automotive Research. ORNL said the 20KW charging system for passenger cars is the world's highest power wireless system. It was developed in less than three years using a "unique architecture that included an ORNL-built inverter, isolation transformer, vehicle-side electronics and coupling technologies."

Comments

270% efficiency

[ShanghaiBill]

A Tesla charger has an efficiency of over 90%. If this charger has an efficiency three times that, then it should be above 270%. Maybe it can feed the extra 170% back into the grid.

Re:270% efficiency

[Anonymous Coward]

TFA states 90% efficiency at 3x the rate, bad summary is bad

Re:270% efficiency

[ebrandsberg]

If it charges at 3x the rate, that implies it's ability to pull power is at least 3x what the wired charger is pulling, and it would have to pull that from... a wired connection. This implies the main problem is that the car interface is simply designed to run at a lower power level than this wireless design, and this could be corrected by bumping up the wired interface charge capacity. This is just a case of leapfrogging specs, nothing more.

Re:270% efficiency

[tal_mud]

A Tesla charger has an efficiency of over 90%. If this charger has an efficiency three times that, then it should be above 270%. Maybe it can feed the extra 170% back into the grid.

The article poster mis-quoted the article. The article actually states: "achieved 90 percent efficiency at three times the rate". So it is the same efficiency as the tesla, but it charges three times as fast.

Re:270% efficiency

[michelcolman]

A Tesla Supercharger charges an empty 90 kWh battery to 80% in 40 minutes. That would be 108 kW, right? And the new wireless demonstration is 20 kW, the first step into creating an unbelievable 50 kW charging system? Yawn...

O, but of course it's wireless, so it will save you a massive amount of time! Sure, it will take an hour and 26 minutes to charge that same battery to the same 80% BUT when you have to connect to a supercharger it can take up to 60 seconds to plug in and unplug! Wireless is obviously better then.

Re:270% efficiency

[AmiMoJo]

Tesla chargers are 120kW, and the more common CHAdeMO used by the Nissan Leaf is 50kW in it's currently deployed form. So if they can get up to 50kW they will have matched currently available wired technology, except that 50kW is not really enough and will be replaced by 100kW+ chargers in the next few years.

Rapid charging needs to average about 30 minutes per charge to be useful. So that means charging at 1.5C, i.e. 2x the capacity of the battery plus some extra for losses. 30 minutes is the average, if you arrive with 1% charge it will take 45 minutes but most people arrive with at least 20-30%.

The minimum battery capacity for a mainstream vehicle seems to be about 60kWh, which will give you a solid 200 miles range under realistic conditions with some margin for safety. So the charger needs to be at least about 100kW to hit the 1.5C + losses target. That's why Tesla supply 120kW.

This misses the point of wireless charging though. No need to plug in, just install it in car parking spaces and let the car charge for an hour or two while you go round the shops. 20kW is actually already quite adequate for this. I regularly charge at 7kW when shopping.

Interference potential

[bromoseltzer]

Can't find any clue as to what frequency is being used for the charger. The prospect of 50 kW of power in your garage or wherever is worrying, despite being "well shielded". Even if it's a lower frequency (in the kHz range), there will be harmonics all over the spectrum, putting radio amateurs and anyone else using sensitive radio gear in a bind.

Re:Wireless charging is probably dangerous

[ShanghaiBill]

There's an abundance of research showing that strong electric and magnetic fields can be hazardous.

No there isn't.

It's also been shown that too much exposure [to MRI] causes cancer.

Total BS.

Re:Wireless charging is probably dangerous

[cheater512]

Who said a MRI is dangerous? Thousands of people have them every day with no increase in cancer risk.

If you bring a large chunk of metal in to the room then sure it's dangerous but that's more to do with the metal flying physically towards a magnet rather than cancer.

10% loss!!

[thesupraman]

Yes yes, terrible summary.

The 'fun' part is the 10% coupling waste (versus I would imagine much less than 1% for plugin charging).
Remember, we are not talking about the battery charge efficiency here, their 10% is just for the transfer of power to the car..

So, thats 'only' 2kw continuous loss. Thank god everyone is converting their houses to LED lighting, which still wont
offset the losses here.

Go Progress!

Re:Wireless charging is probably dangerous

[Plus1Entropy]

There's an abundance of research showing that strong electric and magnetic fields can be hazardous.

Sure, like the electric field formed between clouds and the Earth, but only if you happen to be around when the field discharges.

Re:I have to call BS

[aXis100]

You do realise that inside many DC-DC converters, and indeed inside all of the power transformers between the power station and your house, there are magnetically coupled coils that effectively transfer the energy "wirelessly".

The difference in this case is using an air cored coil at a greater distance. It's definitely harder to make them efficient but they have clearly shown great potential here, with 90% efficiency versus DC-DC converters at 95% and regular transformers at 98%.

Re: Wireless charging is probably dangerous

[scrote-ma-hote]

Not MRIs. When I did a paediatric anaesthesia fellowship we would routinely sit in the room for the scan. Think cardiac MRIs requiring breath holds. The techs sit outside the room cause they need to use computers to run the scanner and also it's really (unpleasantly Even with quality ear protection) noisy. Plus something about pressure in the room that I never understood.

Beware totalitarinism

[mi]

This is awesome news, but there is a threat here:

may someday allow roadways to charge vehicles while they are being driven

I'm fairly certain, that future technology will not allow anonymous charging. It could, but it will not — for the same gratuitous reasons you can't use and recharge a toll-paying transponder anonymously (the way you could use a phone-calling card, for example), but must associate it with both yourself and your car. (Well, New Hampshire, sort of, makes it possible to avoid providing your name, but the cars must still be listed in advance.)

And it is increasingly impossible to drive in certain places without such a transponder, which is, of course, routinely used for surveillance.

As happened with electronic toll-paying, the on-the-road charging too will go from optional to mandatory. Manufacturers will reduce the battery-sizes in many models to save weight and space — and how much of a charge do you need to get from the powered highway to your home (over unpowered streets), right? Effective tracking of your car will become possible. Worse, it may also become possible to remotely disable your car by revoking your access to these chargers.

Today's concerns over license-plate readers may then appear naively quaint...