Small fuel cells processing

The significant issues concerning the miniaturization of fuel eells will be developed, showing notably which kinds of fuel cells ean fit to the requirements of portable electronies and which kinds of fuels may be appropriate for the supply of small fuel cells. Major microfabrication techniques will be briefly introduced, in order to make more understandable the review on microfabrieated fuel cells. Finally the eomplete fabrieation process of a mi-... 

Chang H, Kim JR, Cho JH, Kim HK, Choi KH. Materials and processes for small fuel cells. Solid State Ionics 2002 148 601-6. 

Natural Gas. Small fuel cell systems that are stationary and have ready access to a natural gas pipeline will predominantly take advantage of the natural gas availability (just as in the case of a larger stationary fuel cell). The principal constituent of natural gas is generally methane, CH4. The cost per unit energy for natural gas is the most attractive, and compactness is presumably not a major issue. Since its storage characteristics are not attractive and its processing system is no more favorable than that of LPG, these are likely to be the only circumstances under which natural gas would be utilized in small fuel cells. 

Aviation Fuel or Diesel Fuel Aviation and diesel fuels are preferred for military applications since they are the most available and safest (very low vapor pressure). Their availability is also a key factor in certain under-developed regions. On the other hand, these are the most difficult to process (leaving out heavier fuels, like heating oil). This is attributable to the difficulty of breaking down their larger molecules and to their relatively high sulfur content. Therefore, such fuels would generally be avoided for small fuel cell systems. 

The complexity of the overall fuel processing system for carbonaceous fuels indicates the challenge associated with adapting conventional fuels for use in small fuel cell systems. Considerable effort is required in designing and optimizing the system to achieve the requisite miniaturization and low cost in these applications. 

GM has a multi-year collaborative research agreement with ChevronTexaco to advance fuel cell technology and gasoline processing for fuel cell vehicles. This will accelerate GM s gasoline-fed fuel cell vehicle to retail customers. GM also has an agreement with Suzuki Motor Corporation to collaborate on fuel cell vehicle development, focusing on small cars. 

Portable fuel-cell systems are systems that produce electricity for devices with a performance ranging from several watts to 10 kilowatts. The heat produced in the process is a by-product that is normally not used. The system has, therefore, to be cooled down by fans or cooling surfaces, etc. A wide range of applications is possible for fuel cells from small electronic devices like camcorders, mobile phones, laptops, etc. to electric tools, back-up systems, or power generation on boats or caravans. 

Because of the modular nature of fuel cells, they are attractive for use in small portable units, ranging in size from 5 W or smaller to 100 W power levels. Examples of uses include the Ballard fuel cell, demonstrating 20 hour operation of a portable power unit (32), and an IFC military backpack. There has also been technology transfer from fuel cell system components. The best example is a joint IFC and Praxair, Inc., venture to develop a unit that converts natural gas to 99.999% pure hydrogen based on using fuel cell reformer technology and pressure swing adsorption process. 

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