September 10, 2007
Ultracapacitor For Electric Cars From EEStor?
A Texas company might have an ultracapacitor design that will make electric cars a reality.
An Austin-based startup called EEStor promised ''technologies for replacement of electrochemical batteries,'' meaning a motorist could plug in a car for five minutes and drive 500 miles roundtrip between Dallas and Houston without gasoline.
Observers hesitate to dismiss this secretive company because they've managed to attract big name venture capital investors.
The deal with ZENN Motor and a $3 million investment by the venture capital group Kleiner Perkins Caufield & Byers, which made big-payoff early bets on companies like Google Inc. and Amazon.com Inc., hint that EEStor may be on the edge of a breakthrough technology, a ''game changer'' as Clifford put it.
A game changer advance in batteries would revolutionize transportation and make the coming of "Peak Oil" a small problem. The cost of electric power for electrically powered travel is cheap. A low cost technology that makes electric cars feasible will enable nuclear, solar, and wind power to push our vehicles down the road for two or three pennies per mile.
Do you even think about these before they get posted? Give me a break. A puny 30hp car uses about 22kW continuously, which is about what the electrical capacity *of an entire house* is. Therefore, by using ALL of the electricity fed into an average house, 5 minutes of charges provides about 5 minutes of drive time. That's assuming perfect efficiency.
Do they propose charging at a power station, perhaps? Or is the 500 miles downhill?
EEstor and their ultracapacitors have received a lot of internet attention.
the charging situation has also been discussed. To get 5 minute charging time then you have to
go for an industrial charging station at gas station equivalent locations.
Putting 225 megajoules into a car in five minutes (300 seconds) requires a power supply of 750 kilowatts.
In a U.S. household, the highest voltage available is usually the 240V service for ovens, clothes dryers, and the like. This service is usually limited to about 60 amps...but fast-charging an electric car as we've described would require 3,125 amps. Ready to plug your car into 52 outlets at once? 480V service--as high as you'll probably ever see in a garage--wouldn't make enough of a difference.
The overhead wires in your neighborhood might be carrying "7200/12470Y" power--three-phase AC with each phase carrying 7,200 volts referenced against a common neutral. The effective voltage is that 12,470 kilovolt figure.
Toyota won a 24 hour race using a hybrid with supercapacitors
Problem solved by building the M.C. Escher Freeway across America. That way, you always coast downhill. Don't even need gas.
The claim is a 500 mi charge in 5 minutes.
500 mi = 800 km
5 min = 300 sec
I have researched electric cars using NREL’s data, and based on their electric car research and the amount of gasoline used by the Honda Insight, an 850kg sub-compact sized car, I believe that you might get 100km for 50MJ (J= Joule = 1 watt * 1 second) of electricity in the battery.
So 800 km would require 400 MJ of electricity = 400 MWs.
400 MWs / 300 s = 1.3 MW
Watts = volts * amperes
Clearly we would need currents of kilo-amperes at kilo-volts to meet the claim. I doubt if this can be done by untrained people without special equipment.
400 MWs = ~110 Kwh
At $0.10/Kwh The charge would cost ~$11.00, but an Insight would need about $25 of gasoline to make the trip. Of course, the above estimates assume no losses in the charging process. YMMV.
Also remember that the Insight is a very small car -- highly optimized for efficient travel, essentially a 2 person carrier. A more regular sized vehicle might need twice as much electricity.
I most certainly hope this will be wrong in the future:
"An Austin-based startup called EEStor promised ''technologies for replacement of electrochemical batteries,'' meaning a motorist could plug in a car for five minutes and drive 500 miles roundtrip between Dallas and Houston without gasoline."
There's no need to recharge in 5 minutes at home. People usually come home and park their car for the night. So they have hours every day to recharge what little electricity they used that day.
I assumed they were referring to electric refilling stations.
But what is more noteworthy is the smart money behind this company. Those are big name VCs with lots of talent they can call on to evaluate potential investments.
For something with the enormous claimed potential of EEStor's capacitors the investment of $3M looks rather small. Venture capital investments of 10's and 100's of $US Millions would seem more realistic for something like this - the market is going to be huge. If it can convince with working prototypes using quality scam-resistant independent testing I'd think they'd have no trouble attracting big investors. I'm not convinced, much as I'd like to be. If their need to keep their technology secret means that potential investors are kept in the dark it says to me it's either relatively simple and easy to imitate (patent law not up to the task?) or it's not nearly as good as they claim. In the absence of good information I'm inclined to conclude the latter.
Grid reach and capacity is an issue that's going to need addressing even without enormous new demand - renewables need that or ... much improved storage or better still both. I'd love to have a roof covered in solar cells charging my car as well as house batteries (with weeks of reserve), a solar awning over my parking space at work... None of that looks like impossible but real market incentives to get them into mass production could have to wait till peak oil sends prices high enough to see really big capital investments in new technologies - not a few million but billions and tens of billions.
Brian: I noticed a couple of comments at AutoblogGreen about an ultracapacitor issue that I was not aware of:
"I am concerned about safety. At this energy density, and with that amount of dielectric stress, what happens if the capacitor is cracked? Even a single microcrack will at 3.5 kV produce an arc (a hundred megavolts per metre will break down any gas, even sulfur hexafluoride at 300 bar) whereupon the battery turns into a plasma, all the energy comes out in a microsecond and you have the equivalent of 100 lb of TNT explosion - end of battery, car, occupants and technology. This is supposed to be the salvation of EVs not some terrorist weapon."
"I have seen small ceramic capacitor blow up and send little bits of material flying. The eestore device claim is a huge amount of energy. One stick of dynamite is about 1.2 million joules...do the calculation."
I'm not convinced that pure super-cap EV's are going to be practical, even with major improvements. Nevertheless, there is a lot of potential for super-caps in EV's due to the underused potential of regenerative braking in today's hybrid's because of the limitations of chemical batteries in the efficient quick-charge/discharge area. There are a lot of other apps for super-caps as well that have little to do with transportation. The technology certainly warrants some investment.
Think of it as the Darwin Awards for renewable energy car enthusiasts! They install a 1 MW recharge station in their home for 5 minute charges. If they don't kill themselves during the recharge, they're sure to kill themselves when they're rear-ended and the capacitor explodes.
Maybe Osama Bin Laden could convince the airlines to run their jets off supercapacitors?
On the more humble side, I inquired about the Zenn car by calling one of the authorized dealers near me, Fairfax Motors.
My first was a non-productive phone call: the salesman was silent but managed to utter a, "Ummm..." Hmph. My next attempt was an email. I got two responses. The first was a reply with no text. A few days later (after I posted a comment on CNET) a salesman emailed a reply back saying he couldn't discuss it via email and asked if I wanted to be one of the first to buy the car. (I replied that I had a hearing loss and that only email discussions would do.)
During the above, I also contacted Zenn Cars. I have yet to receive a reply.