I've heard people suggest that as a solution
But they don't seem to have considered how many batteries you need to power a car!

Think how heavy the 12V battery in your petrol- or diesel-powered car is. Now imagine having to change 50 of them every 500 miles.

There's also the fact that the batteries are usually built under the floor and round the outside of the car, so they're out of the way, and aren't going to be easily removable.

So, you have to:

a. Standardise battery shape/fitment/technology between EVERY make and model of car
b. Make the batteries easily accessible and replaceable from the exterior
c. Have a big crane at every garage to change them
d. Figure out what the garage is going to do to satisfy demand for batteries at peak times - when people are going to or coming back from work - and you don't have any batteries charged. Make the people wait their in their flat cars?

(and those are just the most obvious issues...)

It's the sort of idea that sounds impressive if you're a couple of students doing some blue sky thinking in a bar, but as someone who's been described as 'relentlessly practical' I think there'll be too many problems to implement it in the real world.
(Son of Sam-i-am We're all as mad as hatters here, Tue 23 Dec 2008, 12:14, Reply)