In reply to Jones Beene's message of Mon, 22 Jan 2007 08:30:31 -0800: Hi, [snip] >http://www.technologyreview.com/Biztech/18086/ > >The first two comments, at the end of the article, are interesting >regarding the technology, but are not dispositive of whether or not this >company is "for real" with the Bettery. > >Also General Motors recently announced ties and commitments to lithium >ion battery maker A123 - which to some observers would seem to mean that >GM was not impressed with EEStor. > >Wrong. To put it bluntly, GM will be the last auto company on the planet >to find the cutting edge of anything new and promising - at least if >they cannot control the company at the Board level. They are a dying >giant on a downward spiral to oblivion, which is a sad thing to see, as >the trend is indicative of how the USA is becoming a second-rate auto >producer drop-by-drop. Chinese torture for the All-American ego. [snip] The EEStor patent is US7033406 which I believe contains a design flaw. They state that the base material (Barium Titanate) is coated with Aluminum Oxide and Calcium Magnesium Aluminosilicate, which coatings are intended to increase the breakdown voltage of the composite. They then go on to calculate the energy density based upon this increased breakdown voltage.
However IMO, what happens in reality is that a high voltage drop will occur across the high breakdown voltage component, and a lesser voltage drop across the Barium Titanate. IOW with such a composite construction, one can't simply apply the full voltage to the entire material for the purposes of calculating the energy density of the whole. The real energy density of any given material is actually a constant, and no "trick" of design is going to get around that. Since they specify that the breakdown voltage of Barium Titanate itself is only 60% of that of the other materials, and since voltage appears squared in the formula, the real energy density of the finished product is IMO going to be nearer 60%^2 = 36% of their claimed energy density, which would be about 3 times the energy density of lead-acid batteries. Regards, Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition provides the motivation, Cooperation provides the means.
