The energy "storage" techniques are no simper than what we have now.
*Im not an automotive engineer here, so bear with me a little if i get some stuff wrong*
Currently, your car has an energy storage system (fuel tank), and an energy converion system (internal combustion engine) which of course converts chemical energy into mechanical energy. A small amount of this mechanical energy is also converted into electrical energy via the alternator which power the electrical system, and finally, a backup electrical power supply is provided in the battery. Now, an electric car would seem to need a pretty quivilent amount of hardware. First you would need a way to convert the electical power into chemical energy If you are using a conventional battery this is very simple since you just apply the voltage across the terminals and it charges. IF you are using another storage device this might take alot more work (like splitting water into hydrogen and oxygen both of which would have to be sequestered). However you do it you end up with stored chemical energy in the batteries of fuel containers. You still have to convert in to mechanical energy. You can use a DC motor with batteries, a fuel cell, or internal combustion engine for various chemicals, whatever you want, but the point is its gonna be equivilent in cost to what is used now.
Also, what you have to realise is that converting energy between different forms is very ineficient. In the origional chemical energy from the source is converted to mechanical energy, then to electical, then back to chemcial, then back to electrical, then back to mechanical. Most energy converion methods are at best 50% efficient, so you can see how large a percent of the energy you are losing in this situation. In the current design you only convert the energy ONE time, from chemical energy in the gasoline to mechanical energy. Yes, energy is used in the minning, transportation and refining of the fuel, but the same goes for the power sources used by power plants. The coal still has to be minned and transported to the power plant. Whatever you use (even nucealr) is gonna be far to espensive due to the enourmos losses in the chain.