Fabrication process analysis and experimental verification for aluminum bipolar plates in fuel cells by vacuum die-casting

► We fabricated aluminum bipolar plate using vacuum die casting. ► Optimal die design was selected by simulation. ► The higher the injection speed of the high-speed region, the more effective the formability. ► In case of bipolar plate, vacuum die casting is beneficial in terms of formability compared to conventional die casting. ► Vickers hardness of fabricated bipolar is about 75Hv. There are various methods for the fabrication of bipolar plates, but these are still limited to machining and stamping processes. High-pressure die casting (HPDC) is an ideal process for the manufacture of bipolar plates This study aims to investigate the formability of bipolar plates for polymer electrolyte membrane fuel cells (PEMFCs) fabricated by vacuum HPDC of an Al–Mg alloy (ALDC6). The cavity of the mold consisted of a thin-walled plate (200mm×200mm×0.8mm) with a layer of serpentine channel (50mm×50mm). The location and direction of the channel in the final mold design was determined by computational simulation (MAGMA soft). In addition, simulation results for different conditions of plunger stroke control were compared to those from actual die-casting experiments. Under a vacuum pressure of 35kPa and for injection speeds of 0.3 and 2.5ms−1 in the low and high speed regions, respectively, the samples had few casting defects. In addition, the hardness was higher and porosity in microstructure was less than those of the samples made under other injection speed conditions. In case of thin-walled plates, vacuum die casting is beneficial in terms of formability compared to conventional die casting.