In this study, cell performance tests and measurements of the pressure drop in the anode flow channels of a micro methanol fuel cell (£gDMFC) were conducted. The effect of different operating parameters on £gDMFC performance was experimentally investigated for serpentine flow-field configuration. Experiments were conducted through a serious experiments with different operating conditions of temperature (40¡B60¡B70¡B80oC)¡Bmethanol concentration (0.5¡B1¡B1.5¡B2 M)¡Bchannel width (0.5¡B0.6¡B0.7¡B0.8¡B1¡B1.5¡B2 mm) and flow rate (10-20 sccm). Experimental results are presented in the form of polarization VI curves and PI curves under above operating conditions. The experimental results show that the pressure drop decrease with increasing current density. It has also shown that the pressure drop always increased with the methanol solution flow rates. The relationship between pressure drop and CO2 bubbles production rate would change with the current density increase. Finally, an optimal channel size of 700 £gm for the present £gDMFC could be obtained.

The main objective of this research is to analyze the performance of micro direct methanol fuel cell (£gDMFC) and observe the bubble behavior of carbon dioxide in the anode flow channel. The flow plate adopted in this study was manufactured through deep UV lithography manufacturing and micro-electroforming manufacturing process. The geometrical configuration of the flow field is in the serpentine form. Transparent acrylic (PMMA: Polymethylmethacrylate) was used to make the terminal plate placed on both sides of the cell in order to facilitate the observation of the bubble behavior of carbon dioxide in the anode flow channel. In this experiment, Micro Particle Image Velocimetry (£gPIV) is used in order to investigate the generation / removal process of carbon dioxide from the anode of micro direct methanol fuel cell (£gDMFC) through a visualized observation method. The behavior of carbon dioxide bubbles in liquidized methanol solution and micro flowfield is also explored. Major parameters of the experiment operation that consist of flow rate of anode and cathode, density of methanol and operational temperature are used to explore their influences on the fuel cell¡¦s polarization curve and power density. The results are presented by V-I curve and P-I curve. The relation between carbon dioxide bubble movement and behavior according to the anode pressure drop are also discussed.

Direct methanol fuel cell (DMFC) were characterized with low operation temperature, high energy density, rapid activation, easy to obtain, easy to carry, safety, stability and low pollution. Therefore, DMFCs were thought as the next generation of power suppliers to replace lithium battery in the future. In order to meet the miniaturization demand of portable electronic devices, this research tried to fabricate a £gDMFC, simplify component, and lower cost by using MEMS technique. This research used TMAH etching, PEACE, and KOH etching, CNT growth technique to fabricate the hill-like diffusion layer (HDL) electrode which combined the channel structure and through-hole silicon (THS) electrode. Another emphasis of this research was to improve the bubble cover problem for £gDMFCs. The bubble cover problem resulted from the CO2 bubble generated in methanol oxidation reaction difficultly removed and resulted in adverse effect for reaction. This research tried to use the surfactants which used in electroforming to improve the bubble cover problem by improvement surface tension of fuel. Experiments show that using the HDL electrode in anode and the THS electrode in cathode would get the maximum power density (0.186 mW/cm2). The powder density of the design £gDMFC is 10 and 2.5 times larger than the one with pure carbon paper electrodes and the HDL electrodes. Surfactant MA was suitable as a wetting of methanol. Bubble size could reduce 1/2 to 1/3 and bubble cover area could reduce 20% by adding MA. Add MA in the fuel cell could help the bubbles remove to avoid the bubble cover problem. Though MA addition would have the adverse effect for methanol reaction, could get the stabile voltage and extend the discharge time.