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Fuel Cells
For many years, the elegant simplicity of the proton exchange membrane fuel cell was a laboratory curiosity. This curiosity gradually has progressed to commercialization in the form of low temperature cells capable of converting hydrogen and oxygen to water and electrical energy, but limited to operating temperatures around 100°C (212°F). Now, thanks to a new membrane made from the high performance polymer polybenzimidazole (PBI), Celanese Ventures, a subsidiary of Celanese, is manufacturing Celtec®-P Membrane-Electrode-Assemblies (MEAs) on a pilot scale. General Characteristics of Celtec® MEAs include:
- Operation temperature up to 200° C (392°F)
- No humidification of reaction gases necessary
- High CO tolerance
- Excellent long-term stability
- Mechanically flexible and robust
- High MEA consistency
The savings generated by high temperature operation mean fuel cell systems with Celtec® MEAs are more cost-effective, efficient and reliable.
A single MEA does not produce enough electricity to be useful, so MEAs are assembled in a stack, separated by conductive bipolar plates and held together between end plates by compression bolts. Many of Ticona’s engineering resins are excellent candidates for use in the construction of the stack and in the peripheral systems that bring in fuel and air and remove water and electricity. Injection molding the bipolar plates and end plates could potentially reduce overall costs and weight, while enhancing design flexibility.
Consider the following Ticona engineering polymers for fuel cell stack components:
- Bipolar plates - Vectra® liquid crystal polymer (LCP) and Fortron® polyphenylene sulfide (PPS) are good choices because of their temperature capability, chemical resistance and, most important, the ability to be loaded with enough graphite to deliver the necessary high conductivity.
- End plates - Mechanically strong reinforced Fortron PPS is able to take the compressive loads needed to hold the stack together so there is no leakage.
- Peripheral system - Outside the cell the peripheral system feeds fuel (methanol, hydrogen, propane or natural gas), oxygen or air and cooling water to the stack, takes away the water produced in the reaction, and delivers power to the world.
Depending on the specific function, Ticona’s engineering resins can bring value and enhanced performance to various components of the peripheral systems:
- Methanol/water - Hostaform/Celcon POM; Fortron PPS
- Gas/hydrogen - Vectra LCP; Fortron PPS; Hostaform/Celcon POM
- Air - Hostaform/Celcon POM; Fortron PPS; Celanex PBT
- Cooling - Hostaform/Celcon POM; Fortron PPS
- Power distribution - Celanex PBT; Vectra LCP; Fortron PPS
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