Thursday, September 17, 2009

Ultra Capacitors

In electronics, capacitors hold power for later use. In that sense they are like batteries. However they hold far less power than a battery. Thousands of times less, which makes them poor substitutes for current battery technologies. However, ultra capacitors, developed back in the 1960s improved on his disparity by orders of magnitude. These high-capacity capacitors hold only 25 times less power than standard batteries. Still too poor for battery-type applications, given their higher cost to manufacture, but moving in the right direction. And if Joel Schindall gets the funding he needs, a new version of this decades old technology will finally have a chance at reaching commercial viability.

Schindall, a researcher at MIT, has developed an ultra capacitor design that includes carbon nanotubes, microscopic threads of carbon grown off of a sheet of aluminum. These nanotubes increase the surface area available for holding power inside the capacitor, increasing its total capacity by 25 times, bringing the ultra capacitor right in line with standard battery capacity.

Why is that exciting? For one capacitors can be charged completely in a matter of minutes, as opposed to the hours standard batteries require. In the time it would take to fill a tank of gas you could completely recharge an ultra capacitor-powered car. Plus capacitors can release power in quicker bursts than batteries, allowing for improved performance in power hungry applications. And ultra capacitors can be recharged thousands of times, allowing them to last the life of your car, as opposed to the seven or eight years you'll get from a standard battery. And I believe, although I can't confirm this, that they weigh considerably less than batteries, and less weight means less power necessary to power the same car.

One last positive? Batteries generally require noxious and dangerous chemicals. Ultra-capacitors use aluminum and carbon. Environmentally speaking they're a far safer alternative.

At current funding levels, Schindall has said ten years was the cost-crossover for ultra-capacitors, when the price would likely drop in line with standard batteries. However, if companies began investing in the technology in earnest this arch could be significantly shortened. Given all the benefits, I sincerely hope one of the major automakers takes up the mantle.

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