Toyota (NYSE:TM) this week released the first photos of its latest concept car, called the Toyota FCV Concept. The Toyota FCV Concept, which will be shown later this month at the Tokyo Motor Show, is an electric car.

It's a "concept car", meaning that it's just for show, but you'll be able to buy something very similar in a couple of years. Toyota says that it will begin selling a car like the FCV-R in 2015 or thereabouts.

But the FCV Concept isn't an ordinary electric car. It doesn't have a battery pack. Instead, it has a system that makes its own electricity, right on board — from hydrogen.

Electric cars, without the batteries

That system is called a fuel cell, and Toyota is just one of several automakers that have made heavy bets on fuel cells — and hydrogen — as a way to power the automobiles of the future.

Fuel cells convert the energy in hydrogen to electricity by oxidizing it. That means the hydrogen atoms are combined with oxygen atoms. The result is electricity — along with water, or water vapor. That water vapor is the only "exhaust" emitted by a fuel-cell car.

Fuel-cell cars have all of the advantages of electric cars. Electric cars are clean and quiet, and Tesla Motors (NASDAQ:TSLA) and its hot Model S sedan have shown that they can be stylish and fun to drive, too.

But electric cars like Tesla's are powered by batteries, special lithium-ion batteries encased in a big battery pack. Those batteries have proven to be a big challenge for engineers and car designers.

Right now, those special batteries are heavy, bulky, and expensive. That means that an electric car that has the range of a conventional gasoline-powered one is also going to be heavy and expensive. Tesla's Model S is sleek and fast, but "heavy and expensive" also describes it pretty well.

Just a few years ago, many analysts believed that electric-car batteries would be getting a lot lighter and cheaper by now. But battery technology hasn't advanced as quickly as electric-car fans have hoped.

That has led automakers to look for alternatives, and fuel cells might be the best of the bunch.

Where will fuel-cell cars get "gas"?

Of course, a fuel-cell car can't be recharged. It requires a tank of hydrogen in order to make electricity. That means you'll still have to refuel your fuel-cell car, at a "gas" station that sells hydrogen.

There aren't very many of those, at least not yet. But researchers are betting that they'll quickly become common if fuel cells show promise. Hydrogen can be made from natural gas, which is both cheap and abundant. It can also be made from water, using a process like a fuel cell in reverse.

Toyota is far from the only automaker investing in fuel cells. Ford (NYSE:F), General Motors (NYSE:GM), and Hyundai (OTC:HYMT.F) all say that they have fuel-cell vehicles coming to market in the next several years. And Honda (NYSE:HMC) already has one, though it's expensive and sells in tiny numbers.

Right now, nobody knows whether fuel-cell cars will catch on with consumers. But it's clear that we'll have the chance to kick the tires on a few before long.