There was a study done a while back that proved the Toyota Prius actually puts out more emmisions over its lifetime when you consider the manufacturing of the batteries.
I would imagine though, that over time if electric cars would become the norm, the battery production would become more efficient as companies refined their manufacturing process, so that eventually electric cars would become (1) better for environment, and (2) cheaper for consumers to use, because they no longer have to pay for gas, just added electric costs (which will be cheaper than gas because you don't have to maintain gas stations, gas transport networks, ect, you just need powerlines).
Actually the lithium used in the hybrids batteries is far more uncommon than oil will ever be. If the wet dream of the greenies was to come true the world would run out of Li in a very few years. Talk about a non renewable fuel...you're looking at it. And its name is lithium.