Toyota has unveiled the assembly line for its upcoming fuel cell vehicle (FCV)—the four-door Mirai sedan—which will go on sale in the US later in 2015. The assembly line, located at Toyota's Motomachi plant in Japan, will churn out an increasing number of the futuristic cars over the next few years. The Mirai is notable for being the first mass-produced car that is powered entirely by a fuel cell. Unlike most electric cars, such as the Tesla Model S, fuel cell vehicles are refueled rather than recharged—in the case of the Mirai, Toyota says it takes only five minutes to refuel the car, which then gives you around 300 miles of range.

Way back in 2010, Toyota signed a fairly large deal with Tesla to develop an electric version of the RAV4. Tesla provided both the battery pack and the electric powertrain. Then, in the middle of 2014, Toyota rather dramatically announced that it was giving up on battery-based electric vehicles, deciding instead to focus on hydrogen fuel cell technology.

For now, the Mirai (which literally means "future" in Japanese) is being produced in fairly small quantities—but responding to increased demand, Toyota will boost production to 2,000 cars next year, then 3,000 in 2017. According to Autoblog, Toyota is "prioritizing quality and precision" for the Mirai. The video below, released this week, shows workers at the Motomachi plant assembling the Mirai's fuel cell system and electric powertrain.

With an MSRP of $57,500—more than twice what a Toyota Prius will cost you—the Mirai is certainly not a cheap car... but it's also quite reasonable. The Mirai is powered by a hydrogen fuel cell, which takes hydrogen (stored in carbon fiber tanks), and combines it (with the help of a catalyst) with oxygen to create electricity and water. Obviously, this process is a bit cleaner than the combustion of fossil fuels.

Beyond its low emissions, though, the main advantage that the Mirai has over battery-based electric vehicles is that you can simply drive up to a hydrogen fueling station, pump gas for a few minutes, and then keep on driving. Toyota is currently quoting a range of 300 miles, but that could change. (In case you were wondering, the Mirai is no slouch, either: Toyota is currently quoting 153 hp and 247 lb-ft of torque.)

Fuel cell vehicles, then, could be the perfect bridge between internal combustion vehicles and clean, green electric vehicles. With an FCV, you get low emissions and the convenience of quick refueling. But as the saying goes, anything that seems too good to be true probably is—and fuel cells are no exception. While hydrogen is massively abundant (it's the most common element in the universe!), we're still looking for cheap, green ways of producing large quantities of it. There's also the issue that hydrogen has much lower energy density than gasoline or diesel, which in turn makes it difficult to store and transport (you have to compress it). And then there's the rather distinct lack of hydrogen refueling stations...

None of these problems are insurmountable, however. Toyota already operates a few hydrogen fuel stations in Japan, and the Japanese government says it intends to build around 100 more this year (the Mirai is being released in Japan first). In the US, California wants to have 100 hydrogen fueling stations by 2020, but right now there aren't many of them at all. It will certainly be a while until the complete hydrogen fuel cell chain reaches maturity, but there's no denying that FCVs could offer a compelling alternative to both combustion-engine and battery-powered electric cars.