EEStor Ultracapacitors for Electric Cars.

[JamesThomas]

"New Energy Storage Unit?a high-power-density ceramic ultracapacitor?for the small and medium electric vehicle market.

The EEStor ESU is projected to offer up to 10x the energy density (volumetric and gravimetric) of lead-acid batteries at the same cost. In addition, the ESU is projected to store up to 1.5 to 2.5 times the energy of Li-Ion batteries at 12 to 25% of the cost.

As a solid state energy storage device, the ESU is projected to have virtually unlimited life  of deep-cycle usage in addition to being rechargeable in just minutes."

Cut and pasted this from: http://www.greencarcongress.com/2006/04/feel_good_cars_.html

The last news I can find on this is from January this year. Anyone have more resent news?

j

[Sataur]

Thats good news for the electric car industry. The only problem with this that I foresee is the possibility (and damage) of a catastrophic failure of the capacitor. One of those caps would hold a heck of a lot of energy to be able to store 2 times as much energy as a Li-Ion cell of comparable size, and while lithium ion cells can explode if the lithium comes in contact with moisture, that would be nothing compared to what would happen if someone accidentally crossed the two terminals of the capacitor with something or themselves. Batteries can store a lot of energy but discharge it much much slower than capacitors can.

Very cool though!

[IronHead]

A little info on Ultracaps

http://www.prestostore.com/catalog.php/tecategroup.com/pd359660

[Sataur]

The ultracaps for automobiles are quite a bit different than the ones sold right now. They have many more layers and don't use porous material like aerogel as the current ones do (ceramic is used instead, which may also be porous). Similar concepts though.

[hartiberlin]

Somebody posted this info.
And I think he is right,
if a 31 Farad 3500 Volts DC charged capacitor is
discharged due to a shortout it is going to be like
a bomb ! Probably too dangerous in a car environment !

So here is the quote..

Ceramic capacitors are not known for their high energy storage capacity. Barium titanate has been used to make ceramic capacitors for quite sometimes, and has nowhere near the energy capacity as claimed by EEStor company.

The claimed 52kwh capacity of the the EEstor device having 31 farads is due to the 3,500 V maximum voltage rating. However, automotive power inverters and power transformers are typically designed to handle battery voltages from 250-500 volts. Since Energy Stored = 1/2 Capacitance x VoltageSquared, reducing the 3,500V down to a more reasonable 500V will reduce the storage capacity of the EEstor from 52kwh down to 1kwh.

Otherwise, working with 3,500V in a personal vehicle is very lethal, especially in the event of an accident. High-voltage capacitors can explode violently upon aging of the dielectric material or other stresses that can lower the dielectric property of the material. In a chain reaction, the entire energy of this supercapacitor can be released as fast as a bomb explosion. If you wanna build a thick, thick bomb-proof casing to contain this 52kwh worth (~140lbs of TNT-equivalent) of energy that can be released in a flash, you will need a lot of carbon fiber layers that will be very heavy and costly. You might have better luck making a Compressed Hydrogen tank out of carbon-fiber reenforcement. H2 by itself without O2 cannot combust. Structural weakness in the carbon fiber tank may allow the H2 to leak out at a fast rate, but it will not explode.

Good luck, EEStor. Y'all will need every bit of it!