Hydrogen Fuel Cell Technology

Hydrogen fuel cells are, in essence, a kind of battery. The hydrogen has potential electricity in it and when run through a fuel cell to be combined with oxygen, that electrical potential is released.

Compared to Battery Electric Vehicles

Unlike a battery electric vehicle (BEV), however, a hydrogen fuel cell vehicle (HFCV) is recharged by refilling hydrogen tanks rather than recharging a battery with more electricity.

Outside of this, both battery electric and hydrogen fuel cell vehicles otherwise operate exactly the same: they use electric motors to propel the car.

HFCVs given off only water from their tailpipe (H2O) and have no other emissions from the vehicle, much like battery electrics.

The main advantage of a hydrogen vehicle is its longer range and faster recharge (refuel) time as compared to EVs.

The chief disadvantage of an HFCV is in its cost, since fuel cells currently require expensive rare metal catalysts - but this is quickly changing.

How Fuel Cells Work

Most hydrogen fuel cells use what's called a proton exchange membrane. In this system, layers of various materials are stacked and the hydrogen gas (H2) is sent through it. Positively-charged H2 atoms are separated from negatives by a catalyst (usually platinum, but new materials have been discovered).

The positively charged hydrogen passes through a polymer electrolyte membrane (PEM) to a cathode. Negatively charged ions are sent through an external circuit to the cathode, creating an electrical current. At the cathode, the two meet again, drawn together by their attraction to oxygen, and flow out of the cell, combining to form water.

Several of these cells are combined to create a fuel cell "pack" much in the same way batteries are combined to create a battery pack of the desired voltage output.

Hydrogen Fuel Cell Vehicles

Currently, seventeen automotive manufacturers are experimenting with fuel cells with on-road models of their vehicles. Honda has the FCX Clarity hatchback while Toyota, Hyundai, GM, Ford, and others all have their own versions also doing road tests.

Hydrogen fueling infrastructure is being built all over the globe, most notably in northern Europe and in Japan.

Most carmakers plan to have their HFCVs on the market by 2015.