"It is mentioned the device cannot explode when being charge or impacted and is thus safe for vehicles" It's easy to compute that fully charged EEStor contains 1.5 MJ/kg of energy. Assuming that polyethylene terephthalate is the bulk of material by mass (specific heat 1.0 kJ/(kgÂK)), accidental discharge of any single unit (in a car crash, for example) would release enough energy to heat it to 1500 C. Melting point of PETE is only 260 C. At that point, battery components will start burning, bringing temperature even higher, and likely setting a chain reaction. And EEStor is extremely fragile, with enormous potential differences across tiny gaps (3500 V across the 10 micron gap). The likelihood of such catastrophic outcome in even a moderate car collision is high.

That's precisely how they manage to achieve these energy capacity numbers. Energy density scales as the square of maximum voltage.

This $542 estimate is based on the estimated price of internet access of $56 for 20 hours. Which, in turn, is based on the following report http://www.unctad.org/en/docs/iteipc20065_en.pdf (table 7) This table is highly suspect. For one, it quotes $23.51 as an "average price" of 20 hours of internet access per month in "high income" countries like United States and such. Come on! Even in 2003, there were plenty of internet providers in United States that would sell you unlimited dial-up internet for less than 20 dollars; add 5 dollars for a telephone line with unlimited local phone calls. In Moscow (Russia), 25 dollars will buy you unlimited internet access for a month with a 320 kbps bandwidth.