Small fuel cells apphcations

H. Chang, paper presented at the Small Fuel Cells for Portable Apphcations, 2005. 

Pt is the most effective practical catalyst known for O2 reduction, which is an important electrode reaction in fuel cells [24]. To achieve efficient utilization of Pt in such appHcations, a large amount of work has been devoted to developing methods for fabricating very small, stable, 02-accessible clusters. Because the den-... 

Portable electronic devices need very low power for their operation, often milliwatts, or at most a few watts up to 10 W. Small low-power fuel cells designed as power supplies for portable devices have been named micro-fuel cells or mini-fuel cells, the latter term being preferred. The term of a miniaturization of fuel cells is also current. The power needed for most electric vehicles and other mobile apphcations is about some tenth of a kilowatt. 

Industrially, BASF Fuel Cells has a commercially prepared, readymade MEA (Celtec ) that shows great promise. The carbon corrosion, PA evaporation rates, and degradation losses are all minimal The demonstrated long-term sta-bUity is excellent, with the abUity to rim for at least 18 000 hours, nearly halfway the United States Department of Energy target of 40 000 hours, for stationary apphcations with only a very small voltage loss over this time period. 

For small power applications such as laptops, camcorders, and mobile phones, the requirements of the fuel cell systems are even more specific than for vehicle apphcations. Low temperatures are necessary and, therefore, PEM fuel eells are chosen. Possibilities for fuel cell systems are the eombination of PEM with hydrogen storage by hydrides or gas eartridges or the direet methanol fuel cell. Such type of fuel cell will be employed in portable phones and ean be adjusted for other portable applications. The requirements for portable applications are mostly focused on size and weight of the system (as well as on the temperature). Other fuel cells are, therefore, not suitable for this kind of applications. Portable devices need lower power than other fuel cell applieations and, thus, DMFC systems may be well suited for this kind of applications. With further technological improvements and better storage systems, PEM fuel cells and DMFC systems will continue to eompete in this market [74,75]. 

This chapter has described the apphcation of HTPBs in fuel and solar cells as well as in aerospace. The three categories of HTP constitute but a small portion of the total polymer production, namely commodity, engineering, specialty and ultra categories, 95.29,4.5,0.2 and 0.01 wt%, respectively. By adjusting the molecular parameters and incorporating suitable additives, the commercial polymers may be formulated for a variety of other applications. 

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