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The Super Supercapacitor [video]

focusforwardfilms.com

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Re: The Super Supercapacitor [video]

#41

Post by Retric »

jws wrote: post #17
hwillis wrote: post #11

Earlier quoted context omitted.

There also exist hybrid supercapacitors, which use a chemical reaction but act like capacitors. The best use of high-power capacitors is not as a replacement, its as a supplement. Current technology is not quite sufficient, but ideally it would mean that anything under a 20 minute drive could run off just the capacitor, which could(with sufficient infrastructure) charge in under a minute. It's not quite filling up on…

I believe turbines have efficiency problems as you scale them down. Ah yes, graph here… http://www.dg.history.vt.edu/images/image5_2.gif which is from http://www.dg.history.vt.edu/ch5/turbines.html And then notice that the smallest turbine on the plot is about two orders of magnitude larger than you need in a small car.

The graph relates to intended use not just physical limitations. Backup generators are generally more concerned with cost and matinace issues than efficecy. So they tend to be simpler and have much lower tolerances. That said, the automotive market is huge so if they ever became popular for say plug in hybrids something in the 30-40% range is vary possible even at 100hp.

Re: The Super Supercapacitor [video]

#42

Post by ableal »

lutusp wrote: post #23
meaty wrote: post #19

Earlier quoted context omitted.

They aren't magic. They have a relatively high self-discharge (or leakage depending on how you measure it) compared to say Li-ion/NiMh cells which means basically they piss capacity away slowly. Don't expect your wonderful supercap car to actually be charged if you leave it sitting there for a few hours.

> They have a relatively high self-discharge (or leakage depending on how you measure it) compared to say Li-ion/NiMh cells which means basically they piss capacity away slowly. Your claim is premature -- they haven't chosen an insulator yet. The graphene sheets are the conducting surfaces, not the insulating layer. Your claims are about the properties of the insulating layer between graphene sheets, which hasn't bee…

Nanoscale is fun. A measly voltage of 1 Volt across a gap of 100 nm means there's an electric field of 10 MV/m. It's kind of hard to keep electrically charged particles, such as electrons, from moving under that kind of stimulus.

If memory serves, in air the disruptive voltage is 30kV/cm (or 3 MV/m) - above that one gets those sparkly electric arcs that melt metal, intentionally or not. (Other than that, air is an insulator.)

Re: The Super Supercapacitor [video]

#43

Post by deadairspace »

mpweiher wrote: post #2

Very cool tech, and the manufacturing process looks doable as well. :-) Except for us poor mac-heads, how is iTunes going to make me some Graphene?? I was a bit disappointed that there weren't any numbers in the film, so I looked them up: http://www.extremetech.com/extreme/122763-graphene-supercapa... Energy density (storage capacity) does seem to be in range of Lithium Ion batteries, better than some, but still arou…

>Energy-wise, we’re talking about 1.36 milliwatt-hours per cm3, about twice the density of activated carbon, and comparable to a high-power lithium-ion battery.

That's not really comparable to any "high-power lithium-ion battery" at all - Wikipedia quotes 250–730 Wh per litre for Li-ion (so 250-730 mWh/cm^3), and a quick calculation with a laptop battery I have on hand agrees - 84 Wh stated in 27x4x2cm = 388 mWh/cm^3.

Re: The Super Supercapacitor [video]

#44

Post by HarryHirsch »

fnordfnordfnord wrote: post #38
rootedbox wrote: post #32

Earlier quoted context omitted.

Turbines are not fuel efficient for vehicles that are stationary as they idle at 20k rpm. Also the exhaust is highly polluting.

Well, maybe not if you try to directly couple them to the tires. You might have better luck if you try powering a generator to charge batteries. What do you mean by "highly polluting"? Highly polluting compared to what?

They run extremely lean, consequently they produce nitrogen oxides like you wouldn't believe.

Re: The Super Supercapacitor [video]

#45

Post by icoder »

Very cool and batteries 2.0 would definitely change the world. But this vid is a bit one sided. To charge something in an instance means a lot of electricity has to run through the wire in a very short time.

Also, being able to quickly discharge might just be as much of a problem as it is a blessing. Imagine all stored power inside a electric cars capacitor system to discharge all at once..

Re: The Super Supercapacitor [video]

#46

Post by ChuckMcM »

At some point this will be pretty killer tech. One of my favorite applications is to put large capacitors into the foundation of a house with solar panels. Back when Maxell was showing of 4.2F car battery sized capacitors we did the math and figured that a house with a 1500 sq ft base foot print could support enough charge to carry it overnight, assuming that you were in a moderate climate (California worked, Minnesota didn't). Once you can go 'off grid' without battery maintenance worries it will become a lot more common I suspect.

Re: The Super Supercapacitor [video]

#47

Post by fnordfnordfnord »

HarryHirsch wrote: post #44
fnordfnordfnord wrote: post #38

Earlier quoted context omitted.

Well, maybe not if you try to directly couple them to the tires. You might have better luck if you try powering a generator to charge batteries. What do you mean by "highly polluting"? Highly polluting compared to what?

They run extremely lean, consequently they produce nitrogen oxides like you wouldn't believe.

If you'd quote a source I might believe.

Re: The Super Supercapacitor [video]

#48

Post by learc83 »

icoder wrote: post #45

Very cool and batteries 2.0 would definitely change the world. But this vid is a bit one sided. To charge something in an instance means a lot of electricity has to run through the wire in a very short time. Also, being able to quickly discharge might just be as much of a problem as it is a blessing. Imagine all stored power inside a electric cars capacitor system to discharge all at once..

>Imagine all stored power inside a electric cars capacitor system to discharge all at once..

True, but right now we drive cars sitting on top gallons of gasoline that's much more energy dense than supercapacitors.

Re: The Super Supercapacitor [video]

#50

Post by Someone »

fnordfnordfnord wrote: post #47
HarryHirsch wrote: post #44

Earlier quoted context omitted.

They run extremely lean, consequently they produce nitrogen oxides like you wouldn't believe.

If you'd quote a source I might believe.

Probably not 100% convincing, but http://en.wikipedia.org/wiki/Chrysler_Turbine_Car:

"Nevertheless, the turbine generated nitrogen oxides and the challenge of limiting them proved an ongoing problem throughout development."

If the amount produced were low, I doubt it "proved an ongoing problem"

Also: https://wpweb2.tepper.cmu.edu/rlang/RenewElec/CEIC_White_Pap...:

"Gas turbines operate best at full-power steady state conditions where they are at their highest fuel and emissions efficiencies. Deviations away from this tuned set point result in significant inefficiencies (particularly with NOx emissions)"

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