I strongly suspect electric cars will win for many reasons in the end...
@The First Dave: “Enough pissing around with Battery Tech”
... And while your at it, stop trying to sail them ships to them Americas, they will never be cost effective or practical. They will fall off the edge of the world. So millions of people won't choose to deal with and go to the Americas. Nope it will never catch on. ;)
"there is a good reason why battery cars never took off a hundred years ago, despite being safer than internal combustion..."
Yes several reasons. Poor weak electric motors, poor low capacity batteries, poor and heavy car materials, poor national grid ... oh there wasn't even a national grid back then! (It took until 1926 for William Weir's committee to sort out the mess. Before that time different parts of the country had different supply voltages and even different types of plugs etc.. it was a total mess).
Meanwhile now and in the decades to come, its getting a lot better. For example,
(1) Electric motors are now vastly stronger (Try looking up some of the insanely strong small magnets around these days) – Myth Busters sometimes uses them (they call them the Magnetic Hockey Pucks Of Death, which isn't far from the truth if you are holding one that you suddenly move near another one thats free to suddenly fly at you. They are getting scary how powerful they are now).
(2) Batteries are starting to finally improve - not perfect but getting much better capacities and continuing to improve.
(3) Light weight car materials have vast potential to be improved upon. For example carbon is very likely to become the manufacturing material of the 21st century and not just carbon fiber, in time I mean also carbon nanotube based materials. Nanotube manufacturing capacity is going to become main stream and rapidly increasing even now, so give these materials another 15 years for the industry to grow more (and so they also become cheaper). Imagine a car even just a 1/5th of the weight of a present day car, that is also much stronger than steel. (5 times lighter is easy for carbon nanotubes). With a difference like that, the car will be able to go a lot further even with existing batteries and motors.
All these factors are improving all the time. The lighter the cars become and the better batteries and motors become, the more electric cars become ever more practical as their power to weight ratio continues to get ever better. At some point their power to weight ratio will make them very attractive to the mass market *average car owner*. (It probably won't produce the fastest cars ever see (any time soon), but then the best technology doesn't always win ;)
Also with electric everything in the car, there will be far less mechanical parts to go wrong, especially in the engines. That factor alone will make electric cars very appealing to many people who don't want to spend their weekend under the car bonnet, covered in grease and stuck in the rain outside their house. Plus fewer engine parts means it will also be cheaper to build the electric cars.
I would however just say that I'm not convinced about changing electrolytes is that safe though, especially when its changed by millions of non-technical people every day. If I splash a bit of petrol on my hand no problem. But some of the chemicals in electrolytes are far worse on humans than petrol (unless you also have a lit match ;) ... which doesn't happen that often ;) ... but anyway, there are multiple factors converging that all make the electric car ever more appealing to the mass market. So it doesn't matter if its another 10 years from now or another 20 years. Electric cars are becoming ever more appealing.