supercapacitors instead of batteries in electric cars

Hi all,

Recently it was announced that a company called EEStor plans to replace batteries in electric cars with supercapacitors, which hold more charge, charge faster, and contain no hazardous toxins.

My questions are, has anyone done this aleady and what supercapacitors exist already that are useful for this?

Thanks.

Reply to
yubbers9
Loading thread data ...

snipped-for-privacy@yahoo.com wrote:

Haven't heard anything about that. Capacitors store much less energy than an equivalent-sized battery because it's stored as an electrostatic charge between two plates, while the battery uses a chemical change to store and release power. The capacitor's storage depends on the plate area, and the voltage it can safely handle depends on the thickness of the insulation betwen the plates. Most large capacitors have two strips of foil with a thin layer of insulation between them, rolled up and stuffed into a canister. An electrolytic capacitor has a larger capacity because the insulation may be an oxide layer on one foil, or a liquid in the can, or both, reducing the sandwich thickness and allowing more area to be jammed into a given container. A thicker insulation will allow a higher working voltage, but the extra space between the plates reduces the electrostatic effect and therefore the capacity. Like almost anything else, it involves a lot of compromises. Experiments were done years ago using huge cpacitors to try to store the electricity from lightning bolts. Didn't work; the amount of current was so huge and the voltage so high that the capacitors wouldn't take it. It would be neat if it worked; there's an awsome amount of electicity in one lightning bolt. Unless there's been a major breakthrough in capacitor technology, I doubt that a capacitor-powered car will go far at all. Maybe in and out of the driveway :-) So far it's been pretty hard to beat chemical cells. Too bad they're so heavy and expensive and full of nasty stuff.

Dan

Reply to
Dan_Thomas_nospam

Read about Maxwell Technologies boostcap modules..... they stack up their 2600 Farad 2.7V caps into 12, 24 and 48V modules.

Reply to
BobG

There has!

See:

formatting link

A 31 Farad capacitor charged to 3500V holds about 52kWh of energy. Eestor claim to have built such a capacitor from doped Barium Titanate, with plates separated by a few um. It weighs 336 Lbs.

The self-sicharge rate is 0.1% per month, and can be charged and discharged with very high currents without wearing out.

This is not an electrolytic capacitor, and is really could be a storage breakthrough to trigger change in several industries.

You could have one at home to store your solar/wind energy. Or the utilities could use them to supply peak demand.

Now you just need gas stations to offer 10MW charging points.

-- Anon

Reply to
anonymous

formatting link

I have not heard of anyone using these instead of batteries, but rather with batteries to keep surge currents from shortening battery life. A capacitor voltage goes down with the charge level, this could make motor control a lot different. With capacitors and batteries, that is not as much of a problem.

Reply to
SJC

Wow, those capacitors must have been huge indeed. Like the size of a grain silo.

Interesting idea. I'll have to read up on that. I guess the other problem is that lightning strikes are a bit unpredictable, and a 200ft steel tower on a hill with a huge "kick me" sign on it isn't very moveable.

-phaeton

Reply to
phaeton

Have you tried a FLUX capacitor? I have seen them take a direct hit from a lightning bolt. :) sorry in advance.... I couldnt resist.

More seriously though, hydrogen power is promising once they get the cost of it down. I am experimenting with a supplimental device but it's no where close to running exclusively on hydrogen.

Capacitors yes ,are two polarities contained therein but they dont have to just be two plates. 10 Plates, alternating + and - but connected together, would make a stackable system and so on, or in other applications two parallel foils rolled up and stuffed into a tube are used. Ya'll probably know all that but I just like the whole idea of alternate energy sources and had to chime in. good thread.

Reply to
ed

Actually, the ultracapacitors have pretty much replaced batteries for many applications that have long charge/discharge cycles. You will see them in a lot of things like battery backup for clock radios and computer motherboards. They can't dump a lot of current out fast at all, however, so if you need rapid discharge, batteries are still a big win. But the idea is a good one, and the things get better every day.

--scott

Reply to
Scott Dorsey

That sounds backwards.

There may be a difference between supercapacitor and ultracapacitor terminology.

Cars use ultracapacitors because they can be charged and discharged very fast.

Joe Fischer

Reply to
Joe Fischer

I'd be very curious to learn how large the capacitors were that were supposed to hold the lightening bolt's charge, but serious I suspect it they would need to be as large as a house at least area-wise, and so many would need to be place in parallel that they'd be as high as a house!

Reply to
yubbers9

Not with a modern switching motor controller.

Graham

Reply to
Eeyore

How will 'they' get it down ? It's already hugely subsidised.

Graham

Reply to
Eeyore

Lightning contains much power but very little energy. Do some research on that one.

The difference is, lightning is a huge surge of power but it doesn't last very long. You may have millions of watts but when you muliply that by the milliseconds it lasts you only get about $0.20 worth of energy.

Reply to
Solar Flare

Scott's referring to smaller ones. Horses for courses.

Graham

Reply to
Eeyore

-------------- There isn't an awesome amount of energy in a lightning bolt. Estimates range from 55 to 250KWH -(lower one is more likely ) -possibly enough could be collected to supply the clearance lights on a collector tower (Not exactly good from a cost benefits viewpoint) but even this is doubtful as it would take far more than a supercapacitor to do the job. At an isokeraunic level of about 40 thunderstorm days per year, you might get 60-100 strokes per 100 sq km (40 sq. miles) per year.

Reply to
Don Kelly

"EEStor's technology is, based on their patent filing, a ceramic capacitor that can store approximately 50 kwh of electricity, about enough to go 250 miles with current electric cars."

formatting link
As far as I can see this would be a much higher capacity ultracap than anything Maxwell has.

They have a patent on it and a venture capital firm has invested $3m, so who knows?

Reply to
SJC

that can store approximately

anything Maxwell has.

Their sums seem questionable.

formatting link
Graham

Reply to
Eeyore

This was addressed on sci.energy last week. It seems EEStor has inflated the BS by at least three magnitudes....

Reply to
Dan Bloomquist

They will buy cheap power from the Iranians and North Koreans and use a million surplus carbon electrodes from D cell batteries...... ;)

Reply to
Bob Urz

What what the thread subject line?

All I can see is "2700 FARAD Ultra Capacitor.", which talks about regular ultracapacitors (2.7V electrolytics), not 3500V ceramic supercapacitors.

The > Dan Bloomquist wrote:

formatting link
>

I believe EEStor is on to something here. The breakdown field and dielectric constant of the doped Barium Titanate support a *much* higher energy density than the puny Ultra Capacitors.

-- Anon

Reply to
anonymous

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.