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.

wrote:
> 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.

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

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

On Wed, 11 Oct 2006 11:54:58 -0700, Dan_Thomas_nospam wrote:

>
> wrote:
>> 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.
>
> 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,

There has!

See:
http://patft.uspto.gov/netacgi/nph-P...&RS=PN/7033406

> 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.

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

"BobG" > wrote in message ups.com...
> Read about Maxwell Technologies boostcap modules..... they stack up
> their 2600 Farad 2.7V caps into 12, 24 and 48V modules.
>
http://maxwell.com/

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.

wrote:

> 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.

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

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. <long story deleted>

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.







"SJC" > wrote in message
news:dxdXg.2273$i84.1315@trnddc01...
>
> "BobG" > wrote in message
> ups.com...
>> Read about Maxwell Technologies boostcap modules..... they stack up
>> their 2600 Farad 2.7V caps into 12, 24 and 48V modules.
>>
> http://maxwell.com/
>
> 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.

In article <dxdXg.2273$i84.1315@trnddc01>, SJC > wrote:
>
>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.

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

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 11 Oct 2006 19:45:20 -0400, (Scott Dorsey) wrote:

>SJC > wrote:
>>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.
>
>Actually, the ultracapacitors have pretty much replaced batteries for
>many applications that have long charge/discharge cycles.

That sounds backwards.

>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

There may be a difference between supercapacitor
and ultracapacitor terminology.

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

Joe Fischer

wrote:

> 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.

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!