New capacitor research could increase capacities by seven times
Researchers at North Carolina State University have developed a new type of capacitor which allows up to seven times the electrical storage potential as standard capacitors available today. The breakthrough apparently is a polymer called PVDF which can act as a high-performance dielectric, which is an insulating material between two metal surfaces. Electricians are used to using a dielectric grease on electrical connections, so this may be a familiar concept to some of our readers.
This is good news for the electric and hybrid car industry, as capacitors are a possible alternative to batteries. Unlike batteries, which use a chemical reaction to release their stored energy, capacitors use no chemicals and are capable of storing and releasing a given amount of energy quickly. The problem is that capacitors generally store less energy than batteries. This potential, but untested breakthrough could alleviate some of that deficiency, allowing the capacitor to store more energy while still enabling that energy to be charged and discharged rapidly. EEStor is a name that has been thrown around on our blogs, as they claim to have a capacitor based system which rivals expensive batteries in power output, and possibly at less cost. We'll keep our ears and eyes open for more capacitor news, and we'll be sure to pass it along.
[Source: Science Daily, thanks to Matt for the tip]
Reader Comments (Page 1 of 1)
TheTom 3:33PM (7/04/2007)
Would be good for regenerative brakes (able to take in all the power from regen and give it back in a quick burst for the next acceleration). If they can develop the technology to be on par (weight per kilo-watt) with lion or lipo bateries that would be an amazing breakthrough.
Hope it actually works.
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Chris M 5:38PM (7/04/2007)
Multiplying current ultracap energy density by 7, and it would exceed (barely) the energy density of standard lead acid batteries, and would still be well behind LiIon or even NiMH. Still, the "Ultracap X 7" could be useful for power buffering in electric cars, with rapid charging/discharging and almost unlimited charge cycle lifespan.
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Tony Belding 8:12PM (7/04/2007)
It seems like there have been two general approaches to improving energy density of capacitors. One is to improve the dielectric material, which is the EEstor approach, and the other is to increase the surface area of the plates, which is the MIT approach. There is no immediately obvious reason why these two methods can't be combined.
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Michael 9:39AM (7/06/2007)
Combining the EEstor and MIT approaches would certainly seem like a way to get the EV mainstream.
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Ronald C Wagner 5:27AM (7/15/2007)
With a small generator a car could supply power to the capacitor storage if needed. That would extend the range. I believe GMs Volt car will have a generator.
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hassa saad 6:05AM (10/24/2007)
This is going to help human kind very well and improve the performance
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Dennis Zogbi 9:14AM (12/28/2007)
PVDF capacitors have been around for years. Not many know this, but they were used extensively for defense applications going back at least to 1989 and 1990 when they were cited in a public report by CSI Technologies at the CARTS Symposium.
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kingw67 1:51PM (7/30/2009)
KVDF was introduced to the capacitor industry in the 1970s. The material had a dielectric constant of close to 10. It was available in thicknesses of .25 mils (10 microns) to .75 mils (30 microns). Capacitor designers talked in mils. Plastic dielectrics were usually stressed at 5000 vpm or higher. Other material usually ende up in the stress field. When this happened k times stress is constant between then the poles. Any interleave material has a lower dielectric constant and thus has a higher stress. This higher stress causes strange behavior. A finished capacitor charged the first time charges very slowly and becomes very hot. When discharged voltage returns across the terminals. This is generally called dielectri absorption, Actually som materials ionize and cause an inballance of charge across the capacitor.