Fabrication by vacuum die casting and simulation of aluminum bipolar plates with micro-channels on both sides for proton exchange membrane (PEM) fuel cells

Among manufacturing methods for bipolar plates, vacuum die casting is an ideal process because arbitrarily complicated shapes and mass production is possible with a high production rate. We report on the fabrication of bipolar plates with micro-channel arrays on both sides by vacuum die casting for use in proton exchange membrane (PEM) fuel cells. The formability, mechanical properties, and microstructures of samples fabricated under various experimental conditions—molten metal temperature, injection velocity, and vacuum assistance—are investigated, and the experimental and simulation results are compared. The die cavity, which is equal to the bipolar plate area, is 200 mm long, 200 mm wide, and 0.8 mm thick. The active area of the channel is 110 mm × 150 mm, and the total plate thickness is 1.1 mm (the width and depth of the channel are 1 and 0.3 mm, respectively). The cast material used in this study is Silafont-36 alloy (Al–Si–Mg–Mn). Good quality samples with very few casting defects are obtained under the following conditions: molten metal temperature of 700 °C; injection velocities for slow and fast shots of 0.3 and 2.5 m s−1, respectively; and vacuum pressure of 30 kPa.