Actually, lithium-ion is today's leader, which is why all the automakers are using it. Lithium-sulfur and lithium-air, two long-range contenders, are so far off that not much has been written about them yet. Here's a starting point on the challenges of Lithium-ion.
Chuck, thanks so much for the link. I want to cover this topic more from the materials standpoint, since there seems to be a lot of research going on, and I want to make sure I focus on what's most useful to our readers.
Many good comments by various folks! Here are my responses to a few:
Alexander: fuel cells are still ridiculously far from being a cost-effective automotive power source (using ANY fuel, but hydrogen is easiest to implement as far as fuel cells go). They are also still very low power density - so they need to be large if you want realistic horsepower. I think we will see some applications in fixed installations long before any automotive applications.
Jerry: I agree completely - while a "miracle" breakthrough battery would be nice...there are many things that can be done to reduce the energy needed to move the car and therefore make it easier to have a practical and cost-effective EV. see: http://www.edison2.com/blog/month/january-2012 These guys won the "automotive X-Prize" usign an ethanol burning engine...but now have an interesting prototype EV version. 114 mile range on 10.5 KWh's. However, I'll also point out that the low weight and drag of their design also gives awesome performance using fuel-burning engines too.
After researching all the related issues deeply, I find myself scratching my head about what problem the EV zealots think they are solving. First, modern engines are more efficient than most articles say - the Prius is ~38% efficient, and future versions will certainly acheive over 40%. That is higher efficiency than the average coal power plant, and in fact higher than the USA average grid efficiency (coal & natural gas to electricity conversion). The "elephant in the closet" is that EV's do not save energy vs. fuel burning cars (although they do shift from oil fuel to coal+natural gas).
A much more practical solution is to create a liquid synthetic fuel that will supercede gasoline, but leverage all the existing infastructure and vehicle technology. In the short-term, this could be synthesized from coal and natural gas (cut out the "middle man" of the power plants). Longer-term, solar-synthesized fuels or biofuels would create a renewable fuel that has all the conveniences of gasoline without the huge trade-offs of EV's.
In an age of globalization and rapid changes through scientific progress, two of our societies' (and economies') main concerns are to satisfy the needs and wishes of the individual and to save precious resources. Cloud computing caters to both of these.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.