The fuel tank is as safe as safety goes.
First, is a rubber bladder built to withstand severe impacts: only approved manufacturers with ample experience can provide it.
Second, it has more conditions than a spanish girlfriend. Located no more than 40 cm from the axis, nor closer than 30 cm to the driver, it has self sealing breakaway valves in all the entrances and integral hatches. It is enclosed in a crushable structure able to withstand the loads given in article 18. No lines can pass through the cockpit, you cannot mantain more than 2 liters of gas outside it. It is filled with foam (normally, you can avoid its use, but then you suffer from "splashing" and foaming), so even if broken (something I believe it's impossible: the rubber bladder is GOOD) it leaks very slowly.
I think that batteries are ideally suited to replace ballast. I would be amazed if people making the cars don't think about it.
I have no idea why batteries can be used as heat sinks: aren't they a heat source?
Welcome, Professor. I don't like that nick so much as other members... the bitter memories are still fresh within some of us after two decades.
xpensive, what you say is true: the main trouble with energy in this world, our main limitation to a better, less expensive life, it's not energy.
It's the lack of any portable, clean, significant means to store energy. Batteries, ultracapacitors, dams, flying wheels, you mention them, are too cumbersome, too low on energy density.
If you can invent a high density energy storage you would do more for humankind than all the high efficiency
engine designers (with the probable exception of
Charles Parsons).
