Tham khảo tài liệu 'micro electronic and mechanical systems 2009 part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 26 Micro Electronic and Mechanical Systems PEMFC PAFC AFC MCFC SOFC Electrolyte Polymer H3PO4 KOH Molten carbonate Ceramic Charge carrier H H OH- CO32- O2- Temperature 80 C 200 C 60-220 C 650 C 600-1000 C Catalyst Platinum Platinum Platinum Nickel Perovskite Cell components Carbon Carbon Carbon Stainless Ceramic Fuel compatibility H2 CH3OH H2 H2 H2 CH4 H2 CH4 CO Table 1. Descriptions of major fuel cell types In the beginning of research DMFC has been widely investigated as a possible candidate for micro power generation due to the use of liquid fuel and its simple structure Lua et al. 2004 . However the fuel crossover phenomena is an inherent problem of DMFC which severely limits its power output. It is known that the power output of PEMFC is much greater than that of DMFC and there is no fuel crossover in PEMFC. Major obstacle in the successful development of PEMFC is the difficulties of the hydrogen storage with high density. Although possible to use hydrogen in either compressed gas or liquid form it gives significant hazards due to its explosive nature. Metal hydride suffers from high weight per unit hydrogen storage and low response for a sudden increase in hydrogen demand. Chemical storage in the form of liquid fuel such as methanol has significantly higher energy density compared to the suggested technologies. It can be reformed to generate hydrogen gas when needed. The fuel reformer is a device that extract hydrogen from a chemical fuel including methanol methane propane octane gasoline diesel kerosene and so on. The fuel choice is more flexible than the direct fuel cells. Although a fuel cell combined with the reformer is more attractive it is complex and bulky compared to the DMFC due to the fuel reformer. Therefore the miniaturization of the reformer has been a major research activity for the successful development of PEMFC system in recent years Pattekar Kothare 2004 . MEMS technology is a useful tool to reduce the size of reformer and fuel cell .
