2)if one of 30000 components fail, the whole thing shorts
That is a very serious concern.
Especially in catastrophic accidents.
Say, a bullet, shrapnel, bomb or fire.
A momentary short, at 3,500 V, channeled through a fault in one of 31,351 (or one / a few of the 31 million, as I like to think of them (each of the 31,351 "components" is built of 10 units that each have 100 layers)) would almost certainly result in a puff of smoke as stuff melted / vaporized. But that would leave an open circuit, very similar to classic fuses. Possibly only melting / vaporizing the aluminum electrodes into, at worst, a fine mist?
As all of these capacitors are in parallel to the 3,500 V, the EESU would loose the use of the damaged / open circuited units. Quite possibly, that will be a natural state of affairs, within the EESU, especially when first charged. Some inevitable few flawed cells will go poof, but the vast majority will work as advertised?
A big concern is collateral damage. Further debris / shrapnel causing a cascading / chain reaction. That would be a very baaad thing!
3)heat build up in charge/discharge would melt it.
EDIT: I completely missed it / forgot it!
@3,500V, the amount of current is comparatively small.
Any heat generated is proportional to I**2.
Still, 52.2 KWH = 3500 V * 15 A * 1 hour
So, to compress that down to 5 minutes: 180 A, at the + / - terminals.
Spreadout over 31,351 (or 31 million) capacitors.
Very good point.
What's the effective Internal Resistance of an EESU?
Does the self discharge of 0.02% per 30 days suggest that it is super extraordinarily low? Basically just the resistance of the copper conductors and "solder" that interconnects the "components"?
Or that the leakage currents, as reported in the 05812758.0 patent, measured for 10 52.2 KWH EESUs averaged 4.3 µA?
(Those are two sides of the same coin?)
So, the answer might be that the EESU isn't 99.9%, but 99.999999 something % ?
At some incredibly low resistance levels, simply leaving air gaps between the "components", as depicted in that patent, is sufficient for the "small" amount of heat?
Last edited Mon, 02 Mar 2009, 8:16am by nekote
Go DW Go - *economical* mass production
