Simulation and analysis of fiber orientation in injection molded bipolar plates for fuel cell

This research took bipolar plate of Proton Exchange Membrane Fuel Cell (or PEMFC) as the study case, and used Moldex3D mold flow analysis software to analyze the flow of fiber material. The bipolar plate was fabricated through injection molding process, and observed the fiber orientation with Scanning Electron Microscopy (or SEM). This research used PA6 (Polyamide, Nylon6) and +40% carbon fiber. Fiber (Length 200iim / Diameter l0iim). Taguchi methods was utilized to analyze the experiment. It adopted fillet (round corner) design on the channel, and the finished product had a size of l00mmXl00mmX3.6mm, and the channel was 1.2mm in its width and depth. Different injection process conditions were used: channel configuration direction (parallel and vertical to filling direction respectively), melt temperature, mold temperature, injection pressure, hold pressure, back pressure, injection rate and screw speed. Experimental factors were applied to mold test pieces and measured. The results of this research showed that the fiber would turn around and entangle together, and thus decreased the electrical resistance when the channel was vertical to the filling direction. The uniformity of resistance would be increased when the channel was parallel to the filling direction.