Capacitor powered car to give 500 miles on 5 min charge

[Newz2000]

OK, there is obviously some problems with this, and I know that when ever we talk about alternative fuel/power vehicles we get > 60 posts, but this is just too ripe.

Found it on slashdot, the article mentioned says:

In the wake of rising gasoline costs there have been plenty of alternatives seen on the horizon. Including Hybrids, Biofuels, fuel cells and battery powered all electric cars. CNN has recently posted a story about a company (EEStor) that plans on offering UltraCapacitor storage products. The claim being that you charge the ultracapacitor in 5 minutes, with approximately $9 of electricity and then drive 500 miles.

(take a moment to do the math before you read on)

An enterprising individual found the patent and posted this info:

The patent applied
and received is US Patent: 7,033,406

Feel free to yank the patent off the USPTO web site.

Issue Date: April 25, 2006
(Hopefuly they are not 24 days late.)

Unit described in the patent:

Weight = 336 pounds
Capacitance = 31 Farads
Peak Voltage on the capacitors = 3500 V
Energy stored = 52 KwH
Size of Unit = 1 cubic foot (its in there read the fine print)

The patent also describes an energy distribution system that includes "fuel stations" that use the same capacitor storage, and charges capacitors at the fuel station during graveyard shift. (double conversion losses, but that can be argued, and there are MUCH better ways to do this)

The "ultra fast charging" as per the marketing/media blurbs are commented on in the patent, "if sufficient cooling for the charging and wire interconnect is avaialble...." so the guy writing the patent was aware of the issues with the resistive losses in the system.

The capacitince structures are a ceramic technology, using special dielectrics. A lot of content there on the chemistry and fabrication technology.

A couple funny comments about this went something like:
"with that much current I don't think I'd want to stand anywhere near the charging station while in a rain storm."
"Why not just have enough power in the car to get to/from the main high way and then have a cable the cars hook onto like the buses in some countries?" someone else replied, "maybe something like this?"

I think we've got a ways to go before we'll see capacitor powered cars.

[JPKNHTP]

-JPKNHTP

[jwax]

Now there's a kickass battery, oops, capacitor charger-
3500 volts @ about 200 amps, if I figured right.

[Chris Smith]

I can just see it now,.....Instead of a laptop fire, it will be a fire under someone’s butt, and real big?

That or the car melts in two?

[Newz2000]

Now there's a kickass battery, oops, capacitor charger-
3500 volts @ about 200 amps, if I figured right.

Yeah, but look at the size/weight... Am I visualizing this right? Just a bit bigger than a car battery, but 336 lbs! My whole family (all three of us) combined weigh that much.

[ku7485]

Well, at least it's lighter than the battery in the electric Roadster a couple of threads ago. If I recall correctly, I think the battery in there was 1,000 lbs.

[dyarker]

"... then drive 500 miles." and "Energy stored = 52 KwH"

500mi / 50mph = 10Hr
52KWHr / 10Hr = 5.2KW = 5200W
5200W / 746WperHp = 6.97Hp

500mi / 25mph = 20Hr
52KWHr / 20Hr = 2.6KW = 2600W
2600W / 746WperHp = 3.48Hp

Roughly equivilent to putting the engine from a small riding lawn mower in a car.

It doesn't take much horsepower to maintain speed on flat ground, but either the 500mi part is wild exageration or it's a real dog when the light turns green.

IMO of course,

[jwax]

It's the mechanical equivalent of saying my D cell and a 3909 chip can give you "over 31 million" flashes of an LED. Of course it takes it a year to do that.
His mileage estimates are unfounded.
His chemistry is unfounded.
It's a theoretical model.
If the old patent law were still in effect, he'd have to bring in a working prototype. That, IMHO, ain't happening soon.

[Newz2000]

"... then drive 500 miles." and "Energy stored = 52 KwH"

500mi / 50mph = 10Hr
52KWHr / 10Hr = 5.2KW = 5200W
5200W / 746WperHp = 6.97Hp

Roughly equivilent to putting the engine from a small riding lawn mower in a car.

What they probably do is hook an alternator up to the car motor and it generates enough electricity to replenish some of the lost energy from the batteries. I'm honestly surprised they state only 500 miles. Seems like using a technique like this they could go almost indefinately.

[dyarker]

"What they probably do is hook an alternator up to the car motor and it generates enough electricity to replenish some of the lost energy from the batteries." You're kidding, right?? They could get some energy back with dynamic breaking, but still ....

[Newz2000]

Yes, I was kidding.

[MrAl]

Hi there,

Lets take a quite practical look at this...

You have a 31F cap charged to 3500v, and you use it to run
your car motor until it reaches half that, 1750v, at which time
you go to recharge it.

To recharge a 31F cap from 1750v to 3500v in five minutes requires
a current of
i=1750*31/300 amps
or
i=181 amps

BUT, remember whatever power supply is going to supply this
181 amps must be also capable of putting out 3500v too, so
this requires a power supply power rating of
633500 watts.
Granted, this power only has to be delivered for 300 seconds,
but that's still 633500 watts required.

Now lets say the input to this is your home 220v line. The current
required now is
I=633500/220 amps
or
I=2880 amps.

Should we calculate the required wire size now? ha ha.

Now lets say somehow this works. What happens when oodles of
people plug in their charger at the same time, or even for a minute
of overlapping time?

Maybe this is one of those things that should wait until we calculate
our power usage in units of "Lightning bolts per second" ha ha.

[Robert Reed]

Lots of good replys here, but above and beyond anything else, I dont want to be sitting in a rolling package of 3500 volts. Even in in a moderate crash, the crash itself might not cause much harm, but the 3500 volts could very concievably kill you !

[Bob Scott]

Capacitor design varies. You start out with 2 conducting areas of metal separated by a fraction of a distace, then get more capacity by bringing them closer together. Increase capacity even more by replacing the separating air with a dielectric plastic. Get even more by changing the dielectric to an electrolyte. Now it is starting to resemble battery technology.

I think the this "supercap" has crossed the line between battery and capacitor.

Regards, Bob

Designer, patented inventor, blah blah blah

[haklesup]

A super cap may blurr the lines between it and a battery when it comes to capacity, size and energy density. The way they work is still clearly different. A battery uses a chemical reaction (reversable in the case of a rechargable) while a cap simply passivly stores charge on the surface area of its plates.

All else equivelent (size and charge capacity) a capacitor would have the advantage of accepting a charge at a greater rate and potentially discharging faster as well. The linearity of the discharge curve would also vary. Batteries would tend to maintain output voltage longer during discharge while the cap would follow a typical capacitor discharge curve (exponential).

Now if someone invented a battery with so much surface area on its electrodes that one could store an overcharge there, then you might have a true hybrid. Or perhaps a capacitor that could consume part of its plate to recharge without a load or source attached. The advantage to either would be higher peak discharge rates than a battery alone. Or such a combination might serve to flatten the discharge curve to get the best of both worlds (constant voltage and high current discharge)

I keep picturing the way the flux capacitor made the Delorian disappear in a flash of blue sparks in "Back to the future". That's what would happen if the capacitor pack became shorted in an accident.