I think the Tesla uses lithium ion batteries that cost much more, hold more power, and are much trickier to manage in terms of charge and discharge without exploding!
--Lithium battery technology has already surmounted the heat and fire issue in several different ways, among them Lithium Ferrite Phosphate.
The only tricks to managing a Li-Ion battery is that the batteries must be "balanced" before charging as a complete unit.
This is an installation issue and not a regular daily situation.
The only other trait that is noticeable is that a Li-Ion battery MUST NOT be discharged below a certain voltage if you want to maintain good battery life.
This is easily dealt with by smart circuitry that sets a specific cutoff voltage.
Lithium will continue to follow typical market trends until the market for automotive applications makes them cheaper.
So as I said, if this is the worst case scenario, the electric car is poised pretty well and can only get better.
