Toyota showed this fuel-cell powered sedan concept, called the FCV-R, in 2011. A similar car is expected to go into production by 2015. Fuel cell vehicles are emerging as a rival technology to battery-electric cars. Photo credit: Toyota

To hear fans of Tesla Motors (NASDAQ:TSLA) tell it, our battery-operated automotive future is inevitable. But ask experts in the auto business, and they'll tell you that battery-electric systems like the one in Tesla's Model S are just one of several technologies that could eventually replace gasoline engines in our cars of the future.

For instance, Toyota (NYSE:TM) -- the world's hybrid-car leader -- has made a big bet on fuel cells, which enable electric cars to run on hydrogen rather than batteries. Toyota is far from alone -- automakers from Ford (NYSE:F) and General Motors (NYSE:GM) to Honda (NYSE:HMC) and Hyundai(OTC:HYMTF) are putting big bucks behind fuel-cell development as well.

As Motley Fool contributor John Rosevear explains in this video, the future of the automobile is still an open question -- but hydrogen fuel cells could end up having some major advantages over batteries, and that is driving some very big investments.