Current technology of fuel cell systems

A great deal of research is taking place on fuel cells, which use hydrogen and oxygen as their fuel. One of the reasons for this interest is that fuel cells offer the best criteria for meeting the requirements of zero emission vehicles, and thus are expected to be the prime users of hydrogen in the near future. There are presently six different types of fuel cell technologies available-phosphoric acid fuel cells; proton exchange membrane fuel cells; alkaline fuel cells; molten carbonate fuel cells; solid oxide fuel cells; and direct methanol-air fuel cells. This paper looks at each of these six types and gives a brief overview of the technologies and their present state of development. The suitability of the various types toward use in the transportation sector is also studied. Because the selection of a fuel storage method is highly dependent on basic requirements of operational characteristics, the status of the fuel cell technologies is discussed with respect to their basic operating principle, acceptable contamination level, economics and suitability toward transportation. To be used in the transportation sector, fuel cells must meet the demands of rapid startup, fast pickup, high power density, greater fuel efficiency, easy and safe handling, high lifetime and low cost. Unfortunately, none of the six types can satisfy all of these demands at this time, but each has its own advantages and benefits. This paper categorizes each type as to their strengths and weaknesses in meeting these needs