From: xxxxxx@shadowgard.com

> Another problem is that as batteries sapproach (or pass) the energy density of gasoline, they get dangerous. A
> battery fire with batteries that powerful is a *really* bad thing. So are shorts and the like.

Actually, they get plenty dangerous long before that; gasoline's effective energy density is increased (by a factor of 4-5) by the fact that it uses atmospheric oxygen (which isn't really an option for most battery designs, though there are some unrechargeable cells that do so), and if you store oxidizer along with gasoline the result is ridiculously dangerous. Fortunately, we don't really need to match the energy density of gasoline, because the battery is replacing the engine as well as the gas tank (the electric motors are more the equivalent of the transmission).