Nobody knows much about this "ultracapacitor" technology - and one must always be skeptical of technological utopias - but it sure sounds promising:
Imagine the day when cellphones charge up in seconds, laptop batteries never degrade, and electric cars have the same power, driving range and purchase price as their gas-powered cousins.
It's a consumer's dream and an engineer's fantasy: Safe, affordable and eco-friendly batteries that can store immense amounts of energy, allow for lightning-fast charging, and handle virtually unlimited discharging with little affect on quality.
Such a battery -- a superbattery -- doesn't exist today, but a tiny company out of Austin, Texas, is getting remarkably close, and the possibilities have caught the attention of the U.S. army, the former vice-chairman of Dell Computer, and one of the most respected venture capital firms in North America.
Not much is known about awkwardly named EEStor Inc., and the company prefers to keep it that way. It has no website. Hits on Google are remarkably low. And as far as requests from the media are concerned, the company makes its position crystal clear: Go away.
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Just one comment: the news article gives specs for a "17 kWh battery" charge time (4-6 minutes).
A typical passenger car has a ~ 200 horsepower engine. Which is about 150kW.
So such a battery could run the engine at full power for about 6 minutes.
That makes it sound rather less impressive.
Of course at cruising the engine is not running at full power, and a true electric engine is more efficient than a combustion engine. But this is enough to be suspicious.
Also this necessarily implies a recharge power of ~ 150kW, or a current of over 1000 Amps if plugged into a US main electric supply at 110V.
That is another thing to be suspicous about.
Of course the nice thing about high power capacitors is their propensity to explode spectacularly...
They may still have a good capacitor that will find lots of uses, but it is very unlikely to be a main energy supply unit for power intensive applications.
Thanks for your excellent clarifications. I don't imagine I could get very far in 6 minutes, or feel very safe sitting behind a battery that tended to explode.
Gosh, a battery that tends to explode. How dangerous and completely unlike the utterly explosion-proof and noncombustible material that power automobiles today.
And although passenger cars have engines capable of generating 100-200 kW for rapid acceleration, typical driving actually requires something more like 15-30 kW (depending on the loaded weight of the particular car and the drivetrain efficiency, and to some extent on drag). So more like 1.5-3 hours (150-300 km) for the nominal 50-kwH battery capacity.
Where the hype falls down is definitely on discussions of charging rate. You would need an electrical-grid substation for fast charging, and some rather thick, well-insulated cables.
I became interested in UltraCapacitors a few months back. They are really amazing things. I don't know about their propensity to explode, but they do come with warnings that they can put out thousands of amps if shorted. Assuming the safety issues aren't a show stopper, they could be ideal for hybrid vehicles, and power load management.
Fopr say an automotive application, they are much cheaper lighter
and more efficient than a battery, and should not wear out and need replacement. Of course if you want to turn the hybrid into an electric car/hybrid, they don't store enough power -and I think a charge leaks off in maybe a day (if I remember correctly). But for regenerative braking, the battery systems are only about 60% efficient, the UC should be over 99% (of course engine losses are likely much greater).
In any case its a pretty intriguing technology.
bigTom has it nailed. Ultracapacitors are not useful as a replacement for batteries (power density is still far too low), but they are nearly perfect for regenerative braking in hybrid cars and buses, and would do quite a bit for improving mileage in city driving.
Reading the Nature article, I was most surprised by the limitations of fuel cells. While their power density can be excellent, the power output/weight is poor..
Correlating the info from www.teslamotors.com and the Toronto Stock Exchange regulatory filings from Zenn Cars who have a contract with Eestor that they have to report on, plus various other info from the internet you get a big picture that looks like this:-
The Tesla Roadster electric car can do 200+ miles on one charge from its 50 KW Hour Lithium Ion battery pack - and 0-60 mph in around 4 seconds.
The Tesla Roadster causes about 50% of the CO2 emissions of the Toyota Prius (one of the best hybrid cars on the road), though the Prius does 0-60 in over 10 seconds. Compared with a comparable sports car the Roadster causes around 15-25% of the CO2 emissions. All measured on a "well to wheels" basis. That is true even if the power station charging the Roadster is burning coal, and we ought to be able to do much better than this today with electricity generation.
The 50KW Hour Eestor unit is expected to cost around $3,000 (USD) at first and $2,100 (USD) when in real volume production. That is very cheap compared to Lithium Ion batteries. It has a specified discharge rate of 0.02% PER MONTH so it will be 40 years before you notice 10% of the energy has gone missing!!
So the way to charge an electric car fast using the Eestor unit is to have two - one in the car and one in the home. You charge the home unit slowly using cheap overnight electricity, then you can fast charge the car in 3-5 minutes from the home unit at any time. The charging is done at 3000 volts using a cable with nice thick insulation, but it will not be any heavier than petrol pump cables. The home unit will pay for itself as you can use it to make sure you pay overnight rates only for ALL your household electricity usage.
It should be possible to resolve the safety concerns. If Tesla Motors can get US safety approval for an electric car with their 50 KW Hour Lithium Ion battery then Eestor ought to be able to make their unit safe too, using similar techniques or maybe others which are better. In any case safety concerns will always be minimal compared with the numbers killed outright in collisions, or maybe those killed in past and future oil wars if we do not all mend our ways.
There is one slight problem, in my view. Electric cars make much less noise than petrol cars so pedestrians will not be able to hear them coming so easily (particularly a problem if one is trying to do 0-60 in 4 seconds). Maybe they need a "vroom vroom" sound coming out of external loudspeakers to warn pedestrians? There has got to be a better solution than this though!!