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Definition: fuel cell


A pollution-free electricity generation technology for electric vehicles (EVs). Road testing began at the end of the 20th century, and hydrogen-powered fuel-cell buses have been running since the mid-2000s. Toyota has been selling its Mirai fuel-cell automobile since 2014, and Japan, China and South Korea have all set long-range targets for fuel-cell vehicles (FCEVs). See electric vehicle types.

An FCEV refuels like a car at a gas station, except that the gas is hydrogen. A fuel cell takes in hydrogen-rich fuel and air (oxygen) and turns them into electricity. The waste product is water, and although not recommended for drinking, one test by Toyota showed fewer organic impurities than a glass of milk.

The Energy Alternative?
Fuel cells compete with lithium-ion batteries as the source of electricity for the vehicle's motors, but there are challenges. While hydrogen can be derived from natural gas, propane, methane or water, it depends on which sources ultimately make the most sense. In addition, hydrogen is difficult to distribute and stockpile, and installing hydrogen pumps in every gas station is a gigantic undertaking. See lithium ion.

Heat and Power the Home
Fuel cells are also expected to provide a pollution-free source of energy for electricity and heat in the home. This combined usage is a major incentive for fuel cell research and development.




A Ballard Fuel Cell
Ballard Power in British Columbia is one of the largest makers of fuel cells. Separated by a polymer exchange membrane (PEM), the anode and cathode are coated with a platinum catalyst that causes the hydrogen fuel to separate into free electrons and positive hydrogen ions (protons). The free electrons are the electricity, while the ions migrate through the PEM to the cathode and combine with oxygen and returning electrons to form water and heat. (Image courtesy of Ballard Power Systems.)