In reply to Michel Jullian's message of Sat, 27 Jan 2007 14:11:55 +0100: Hi, [snip] >Unless the coatings diminish the material's permeability to some atmospheric >gases lowering it's breakdown voltage? > >Michel
I would think that insulation from the atmosphere would be more cheaply and easily obtained with a plastic sealant. BTW there is no real reason to operate at such high voltages. By making the dielectric material in the capacitor thinner, the capacitance per unit area is increased, and also the total number of plates in a given volume can be increased. Both of these together compensate for the drop in voltage, so in fact any desired operating voltage can be accommodated. It turns out that the maximum *energy density* of the device (J/m^3) is purely a function of the material used as dielectric in the capacitor, and is proportional to the product of the absolute dielectric constant of the material and the square of breakdown voltage strength of the material (V/m)^2. > >----- Original Message ----- >From: "Robin van Spaandonk" <[EMAIL PROTECTED]> >To: <vortex-l@eskimo.com> >Sent: Tuesday, January 23, 2007 10:50 PM >Subject: Re: [Vo]: More on the Bettery > > [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 Regards, Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition provides the motivation, Cooperation provides the means.
