If electric vehicles or their analogous plug-in-electric hybrid vehicles (PHEV) are to become widespread in the face of a lack of cheap oil, some source of battery technology will be necessary to carry the charge to run them. I wrote an article a couple of years ago "Electric Vehicles and World Lithium Supply", October 13, 2006) in which I concluded there was insufficient lithium to fabricate an equivalent of 500 million cars, as was then estimated to be on the roads worldwide, by PHEV's. This was based on the assumption that the world stock of lithium was around 5 million tonnes and that it would take 9 million tonnes to make 500 million PHEV's. For all-electric cars, the situation is worse since they each take four times the amount of lithium that a PHEV would. I did also refer to other kinds of battery technology which use materials that are known to be more abundant.
However, the amount of lithium in the world has now been called into question, and one analyst thinks there is much more of it available , mostly based in Chile's Atacama desert, amounting to an economically recoverable total of 28.4 million tonnes. Clearly that would be plenty: enough for 1.58 billion PHEV cars or almost 400 million fully electric vehicles, so the physical amount of lithium is not a problem. There are also sources of lithium in the Andes and in Tibet, along with hectorite (a lithium containing clay) and oil-field brines that contain lithium, albeit more expensive to extract than the mountain-sources, and the material should be recycleable, so for example a direct comparison with the oil the technology is intended to replace is not strictly justified.
The issue is not without contention, however, since another author  concludes there are 6.2 million tonnes in reserves of lithium and its reserve base is 13.4 million tonnes.
In my opinion, if all sources of lithium are worked-out there is probably enough of it to go round to make 600 million cars, as there are now. It should be noted that there is an increasing demand for the metal to go into laptop computers and mobile phones, and it is anyone's guess what that total demand might amount to.
However, the latter devices are made out of oil too, and with current roaring prices which I do not expect to fall, along with a near and eventual shortage of oil, I see another limiting factor - raw materials to make plastics from and the lack of money in people's pockets rather than of lithium.
60 million new cars are put on the roads each year and if they were made as PHEV's which might take 18 kg of lithium each, we would need an annual production of 1.08 million tonnes of it. This is around 54 times the present output of lithium (20,000 tonnes), and so that production capacity (mining and processing) would need to be installed (a considerable task). If it could be done, we would be "there" within 10 years. However, will there be enough energy to do the job, and what will these cars actually cost.
Given that I see financial distress for many in the West the car may well be seen as a luxury and by default, we will set-aside our travelling lifestyles in the difficult oil dearth years ahead of us. We don't have 10 years in which to begin reducing oil consumption: we need to do that now. If only we had begun 10 years ago we would have saved massive amounts of oil, and be facing-off a future gap in the supply/demand conundrum, with time in hand. We didn't though, but permitted the market-forces to prevail. The present number of cars replaced by fully-electric vehicles will take 40 years to produce, and again against the backdrop of an energy crunch.
Another potential strife is that some kinds of lithium battery contain a phosphate component and I have discussed recently that there are likely to be problems with mining a finite source of rock phosphate which is mainly used for agriculture. As a rough estimate, assuming one phosphate anion per lithium cation in a lithium-iron-phosphate battery (the strongest contender for EV's) 600 million cars would need around 148 million tonnes of phosphate or about 15 million tonnes a year assuming we could equal the world annual total of 60 million new cars annually. That is to be compared with the total phosphate mined for food production of about 140 million tonnes, and so we would need to sacrifice a good 10% of that, while a hungry population rises.
It isn't going to happen, and to conclude once more, car use will be curbed by a combination of factors, with all that implies for civilization.
 "Peak Lithium." By Bill Moore. http://www.evworld.com/article.cfm?archive=1&storyid=1180&first=3171&end=3170
 "The Trouble with Lithium." ByWilliam Tahil. http://www.evworld.com/library/lithium_shortage.pdf