FACT BOOK
FCX 2002.12.2


Electricity made from hydrogen and oxygenthe only emission is water
The FCX's fuel cell stack is a PEFC (polymer electrolyte fuel cell) electrical generation device that employs an electrochemical reaction between hydrogen and oxygen to directly convert chemical energy into electrical energy. This can be viewed as the reverse of the principle of electrolysis, in which an electrical current is used to separate water into hydrogen and oxygen. We have created a clean-running system that is capable of continuous electrical generation when supplied with hydrogen and oxygen, simultaneously generating electricity and water, with no CO2 or other harmful emissions whatsoever.
· When hydrogen is delivered to the hydrogen pole it is ionized by a catalytic reaction with the platinum electrode, emitting electrons. This produces a DC electrical current.
· After emitting the electrons, the hydrogen ions pass through an ion exchange membrane, where they bond with oxygen ions from oxygen delivered to the oxygen pole and the previously emitted electrons arriving via an external circuit.
· This reaction creates a DC electrical current, generating electricity. Water is generated at the oxygen pole as a byproduct.
· Because the ion exchange membrane must always be kept moist, both the hydrogen and the oxygen supplies need to be humidified. To accomplish this, the water vapor generated in the fuel cell stack is recycled, providing the water necessary for humidification.
· The ion exchange membrane is composed of an extremely thin polymer layer (PEM, or proton exchange membrane, which exchanges positive ions). This membrane is sandwiched between two electrodes (the hydrogen pole and the oxygen pole), which in turn are sandwiched between separators on each side to compose one cell.
· These cells are stacked, and when the electricity generated by each cell is combined, a large voltage is produced.
· The FCX employs a compact, lightweight fuel cell stack manufactured by Ballard Power Systems, which outputs 78kW of power. Honda is also conducting research on its own fuel cell stack.
Fuel cell stack
A 350-atmosphere high-pressure hydrogen tank provides
ample storage capacity resulting in a vehicle range of 355km*
Because the hydrogen used as fuel has a low energy density per volume, as much hydrogen as possible must be available to ensure a practical vehicle range. At the same time packaging considerations dictate that as little storage space as possible must be taken up by the fuel tanks.

The FCX utilizes a high-pressure hydrogen tank with a three-layer construction composed of an aluminum liner, carbon fiber, and glass fiber, for superior strength and corrosion resistance, to achieve a filling capacity of up to 350 atmospheres. Two of these tanks are employed to secure a 156.6L fueling capacity. This large capacity plus improved fuel consumption results in a vehicle range of 355km*. Fueling time at a high-pressure fueling station is only three minutes, for a level of convenience comparable to that of a gasoline-powered vehicle.
* Honda in-house measurements when driven in LA-4 mode.



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