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Written by Daniel
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Wednesday, 05 September 2007 09:49 |
Supercapacitor "battery" could lead to instant charging, long charge life
ARS Technica
By John Timmer | Published: September 04, 2007 - 09:41PM CT
The batteries we rely on for everything from our cars to our cell phones use a chemical reaction to store and release an electrical charge. The chemicals involved force a large number of tradeoffs in terms of practical considerations, such as weight, toxicity, heat, and the slow charging process. News is filtering out that a small startup company in Texas has made a breakthrough in charge storage that relies on a completely different technology: capacitors. Details are scarce, but a company that has licensed the technology suggests that it's ready for large-scale production.
For those of you who don't remember high school physics, a capacitor stores charge by arranging two metal plates in parallel. Placing a negative charge in one of the plates will repel electrons from its opposite; this charge difference will be maintained as long as the two plates remain electrically isolated and can be harnessed to produce a useful electric current. A key advantage of capacitors is that they can store charge just as quickly as it's supplied—the long charge times needed by chemical batteries are simply unnecessary. With no chemical reactions involved, capacitors should also have an indefinite life span.
These features may lead you to wonder why everything isn't running on capacitors. The primary limit to the amount of electrical charge that can be stored in a capacitor is the amount of insulation between the plates, which prevents a current from jumping directly between them. Existing insulators simply aren't good enough to support a charge density comparable to chemical batteries. In short, capacitors with a sufficient charge capacity take up far too much space.... More
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