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Page 1 of 2 Ultra capacitors & Super Capacitors store electricity by physically separating positive and negative charges—unlike batteries which do so chemically. The charge they hold is like the static electricity that can build up on a balloon, but is much greater thanks to the extremely high surface area of their interior materials.
• An advantage of the ultracapacitor is their super fast rate of charge and discharge... which is determined solely by their physical properties. A battery relies on a slower chemical reaction for energy. • A disadvantage of an ultracapacitor is that currently they store a smaller amount of energy than a battery does.. which makes them larger.
Ultracapacitors are very good at efficiently capturing electricity from regenerative braking, and can deliver power for acceleration just as quickly. With no moving parts, they also have a very long lifespan. An ultra capacitor, also known as a double-layer capacitor, polarizes an electrolytic solution to store energy electro statically. Though it is an electrochemical device, no chemical reactions are involved in its energy storage mechanism. This mechanism is highly reversible, and allows the ultra capacitor to be charged and discharged hundreds of thousands of times. Once the ultra capacitor is charged and energy stored, a load (the electric vehicle's motor) can use this energy. The amount of energy stored is very large compared to a standard capacitor because of the enormous surface area created by the porous carbon electrodes and the small charge separation created by the dielectric separator. Here is a very basic example of how an ultracapacitor works by using a circuit that uses a dc motor. TECHNICAL DESCRIPTION: An ultracapacitor can be viewed as two non reactive porous plates, or collectors, suspended within an electrolyte, with a voltage potential applied across the collectors. In an individual ultra-capacitor cell, the applied potential on the positive electrode attracts the negative ions in the electrolyte, while the potential on the negative electrode attracts the positive ions. A dielectric separator between the two electrodes prevents the charge from moving between the two electrodes. UltraCaps are currently used for wind energy, solar energy, and hydro energy storage.  Electrical energy storage devices, such as capacitors, store electrical charge on an electrode. Other devices, such as electrochemical cells or batteries, utilize the electrode to create, by chemical reaction, an electrical charge at the electrodes. In both of these, the ability to store or create electrical charge is a function of the surface area of the electrode. For example, in capacitors, greater electrode surface area increases the capacitance or energy storage capability of the device. A third type of storage device, the ultracapacitor, relies on the microscopic charge separation at an electrochemical interface to store energy. Since the capacitance of these devices is proportional to the active electrode area, increasing the electrode surface area will increase the capacitance, hence increasing the amount of energy that can be stored. This achievement of high surface area utilizes materials such as activated carbon or sintered metal powders. However, in both situations, there is an intrinsic limit to the porosity of these materials, that is, there is an upper limit to the amount of surface area that can be attained simply by making smaller and smaller particles. An alternative method must be developed to increase the active electrode surface area without increasing the size of the device. A much more highly efficient electrode for electrical energy storage devices could be realized if the surface area could be significantly increased.
*Patent - Author - Year -Title -Country -Assignee -Number -URL
Davis, James L.; Williams, Melanie; Pennisi, Robert W.; 1998 Electrical energy storage device having a porous organic electrode United States Motorola, Inc. (Schaumburg, IL) 5748438 http://www.freepatentsonline.com/5748438.html
Readers have left 10 comments.  No.1 Carbon Nanotubes as Electrodes?Hm I wonder if carbon nanotubes could be used, grown by microwave in a similar fashion to which researchers at Purdue University recently applied to silicon for heat transfer in silicon based computer components. Ultracapacitors grown in this fashion would have a very high electrode surface area, assuming that it can be done, wouldn't that be nice
http://www.tgdaily.com/content/view/34147/118/ No.2 Carbon nanotubes ultracapacitors in MIT
It already exists in fact. Check out Joel Schindall's work at the MIT. He uses chemical vapor deposition though to make the nanotubes grow. No.3 Boat Designer
I have a design for a boat that makes power and currently, the only way I have to store it is in a battery. Would it be possible to design the whole boat or parts of the boat as an ultra capacitor? What would be the advantages/disadvantages? No.4 Untitled
I love Joel Schindall and the work he has done. No.5 Associate Professor
About the boat, making the structure out of ultracapacitors my be an unsound idea. It's like taking a bath with lots radios plugged in. These devices have high voltages. No.6 Professional Engineer
The boat idea has merit and with variation could be extended to almost any vehicle. Keep in mind though that most polymers in a water immersion environment will need some form of protective coat because of porosity. The hull would need to be constructed of multiple layers of which an outer set would need to be designed for RF shielding/grounding and to control potential electrolytic degradation. An inner set could be the actual ultra capacitor and in fact I would suggest constructing that in isolated sections with a control module connecting them. This way you can manage power more effectively. If you have ever seen a electrolytic or ultra capacitor explode in a short circuit you will agree. This will also allow the storage voltages to be maintained at a manageable level. I think you will still need some form of rechargeable battery, at least for the near future, but imagine how a new generation of Polaroid Pola-pulse type battery might be integrated into the hull as well. There is no technical reason why you cannot integrate structural and functional components but it does require a thorough analysis of the operational, environmental and functional variables to come up with a workable design; either that or dumb luck, which I have seen before. No.7 artist/hobbist/designer
I am working on the charging system of my electric car!I want too use super capacitors as a means to help charge an auxiliary battery pak,to extend the driving miles per charge.I am using a d/c charging unit,d/c battery storage,d/c electric motor to power the vehicle.I want to incorporate a bank of S/Capacitors to charge the battery paks.A relay will switch to the auxiliary battery pak when the primary battery pak is 80% discharged.I am using a wind powered D/C generator I have built to charge the A/pak.Too increase the watts,volts,amps I want to charge a bank of supercapacitors that are being charged by the d/c generator,then discharge the S/Capacitor storage bank into the battery pak.I have done successful testing on a small scale,small d/c generator,small electric fan&motor,and a battery pak of (2)12v deep cycle lead-acid batteries.I would like too hear from you...thanks!!!
No.8 GIS Tech/Retired Navy
The Boat idea float!. As the eartlier comment was made about layering to provide RF shielding and grounding is correct. Thinh of double hull tankers. Not that the space between the hulls need be an air gap, the inner hull of S/caps would be protected from damage if you ran aground in the lake shallows or where storm tossed into the pier pillings. No.9 Solar Lights - LEDs - Developing World
Dear All - I make solar lights for the developing world - replacing kerosene lanterns. Views on if I can replace my three AA batteries with an ultracapacitor?
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