Exchanging batteries is about the only viable option I can see for "fuelling" electric cars. Battery technologies have been invested in recently, since the boom in mobile devices. The electric cars we have today are only as viable as they are thanks to investment in the Li-Po batteries and their derivatives we have in our phones, tablets, etc. I can't see a revolution coming any time soon, although we will no doubt see steady improvement. We need much better than that.
The problem you then have is that we need a standard battery that fits all cars. Currently electric car batteries are a very irregular shape to maximise their volume by utilising every bit of space under the car to which they belong, so very vehicle specific.
The next problem is funding the batteries. Somebody has to own them, and the distribution and charging network, and replace them when they die... I can see roadside battery replacements as being a very expensive fuel.
Only when everyone has one! To start with they will be cheap. Think discount of diesel over petrol at outset.
I'm not convinced about that philosophy. Very few cars remain in motion continuously and thus if the range was adequate and the availability of charging stations were ample then you would have no problem. Even better would be energy transfer in the road while you were driving. We are a long way off the latter, but the range of the tesla and it's battery is a game changer. Couple that with the ever expanding network of chargers and you have a feasible option.
The leaf needs another 60 miles of range to be a real option for the future. Maybe the next version will be better, but as a town runabout it is fantastic. I drove up to Sheffield a few weekends ago and I knew I would have to charge up twice. The journey took 4.5 hours including the charging. The first charge session coincided with lunch. So it was time I would have spent stationery regardless of the vehicle i was using. The second charge was a toilet stop after which I did have to wait another 20 mins. But because the charging points were free the entire round trip cost me about £2.50 in electricity. Compare that with a car (between £60-100 in petrol) or the train (quoted at £100 ish) so each minute I waited saved me between £2.50 and £4.
I think that we are around the corner from milk floats becoming a viable option as an only car. Remember, when motor cars were invented there was the same resistance and fears about range, longevity, etc....
"What do you mean you can't just let it roam in the paddock and refuel!!??"