DMFC bipolar material and new processing for μDMFC microchannel

DMFC (Direct Methanol Fuel Cell) is attractive as green energy with the characteristics of high energy conversion rate, lower carbon and emission, eco-friendly alternative energy. In DMFC, bipolar plate is one key component because of its high performance requirements, the bipolar plate nearly always makes about 60% contribution to the cost of all fuel cell, seriously affected the commercialization progress of DMFC. Furthermore, the flow channel design and arrangement in bipolar plate has a great influence on water and heat management, distribution of reactants and smooth resultant discharge. So the DMFC bipolar plate material and flow channel processing technique obtains more concerns. After introducing the bipolar plate structure and its functions, it points out that the bipolar plate material nowadays mainly involves the graphite materials, metals and composite. Then the corresponding preparation method, advantages and disadvantages of these three kinds of bipolar plate materials are analyzed. With the rapid development of Micro and Nano-technology and the demand for electricity supply of MEMS (Micro Electro Mechanical systems, micro-energy sources have been the focus, resulting in the miniaturization DMFC (μ DMFC). As the micro-bipolar plates has to survive the severe rugged working environment, such as high temperature, deep-etching, multi-field and alternating pressure), which challenges the material selection, flow channel configuration, processing method and precision. Therefore, hard-to-deform material such as titanium alloy is the preferred material for micro-bipolar plate. However, the new processing method has to be initialized for hard-to-deform material. This paper introduces the traditional and advanced processing methods of μDMFC bipolar plate. The existing problems of the DMFC bipolar plate material selection and processing are analyzed. We initialized one new technique that combines the laser-assisted heating method and micro die-pressing. The laser functions as the heater to warm up the micro sheet metal to reduce its forming force and improve the formability of hard-to-deform materials, which increase the possibility of die-pressing micro-bipolar plate in one stroke. It also means the potential prospect of processing of micro-channel.

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