Abstract: | Cell performance tests and measurements of the pressure drops in the anode flow channels of a custom‐made microdirect methanol fuel cell (μDMFC) are conducted and studied for different methanol concentrations (0.5–2 M), flow rates (10–20 sccm) and operating temperatures (40–80 °C). The anode flowfields consist of three channel/four pass flow channels with widths of 500–2000 μm and a total length of 300–400 mm. Moreover, flow characteristics of the CO2 gas bubbles and methanol solution in the anode flow channels are identified and analysed for CO2 fraction through visualisation. Finally, an optimal channel size for the present μDMFC is obtained. |