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Archive for March 9th, 2009

EEStor Super Capacitor

Posted by David Bradley on March 9th, 2009

A Texan company, EEStor, claims to have developed an entirely new type of capacitor for storing electrical energy. Their Electrical Energy Storage Units (EESU) can apparently store enough energy to power a small car for almost 500 km. The same technology might be used to “backup” electricity generated from periodic alternative energy sources such as windpower and wavepower.

EEStor’s CEO and president Richard Weir, named as co-inventor on the company’s main patents was interviewed last year by the Barium Titanate blog, but other than that there is scant information about EESUs.

Are they a scam like so many other claims for perpetual motion and free energy? If only, the company would tell us more, science could decide.

EEStor’s patents describe the sintering of tiny grains of coated barium titanate powder into a bulk ceramic, which is claimed to eliminate pore spaces and so take full advantage of barium titanate’s extremely high permittivity without void arcing that would otherwise discharge the capacitor. Sounds reasonable, so far.

However, there are many skeptics. Jim Miller, a capacitor expert who visited EEStor in 2007 to evaluate the technology reckons there will still be current leakage at the typically high operating voltages caused by microscopic fractures in the sintered ceramic caused by temperature fluctuations.

Andrew Burke, another expert who visited EEStor also says that the permittivity could not be maintained at the high level claimed at the high voltage required. The energy density could not be that high, he says.

EEStor will apparently not provide supporting data for their claims to contradict the experts. Such reluctance to share knowledge and evidence around such a potentially revolutionary device inevitably leads to more skepticism than support. The EEStor website is still labeled “under construction“, which does not inspire confidence. Wonderful as the idea of a supercapacitor to help us harness renewable energy may sound, one cannot help but feel that EEStor is probably just another Steorn in a teacup.

By the way this article is about storage units, but those of the electrical kind, seems a lot of visitors are arriving looking for boxes and shelving and such like.