Digital Light Processing 3-Dimensional Printer to Manufacture Electrolyzer Bipolar Plate

Abstract

Bipolar plate is one of the largest and most important components in Polymer Electrolyte Membrane Electrolyzer and Fuel Cell that functions as a cell separator, electrical and heat conductor, reactant feed distributor, for the flow of gas-liquid mixture and supporting components for the Membrane Electrode Assembly. In general, injection, compression moulding or Computer Numerical Control-machines are commonly used to produce bipolar plate. These methods, however, cannot be used to produce complex 3-dimensional shapes, such as vertically inverted cone shape or creating a channel inside the plate. By using a 3-dimensional printing machine with laser-based stereolithography or digital light processing, complex design problems and problems in making channels in the plate can be solved easily. In this study, polymer-based bipolar plate was developed using 3-dimensional printing technology which was made conductive by introducing nickel and gold layers through spray coating and electrocoating processes. The nickel layer was optimized by controlling the applied voltage during electrocoating. Since low voltage formed very thin layer whereas high voltage caused "burning" of the sample, applied voltage of 5V was found to be the optimum condition. Employment of gold layer increases the conductivity from 300 S cm-1 to 400 S cm-1 which enabled the corrosion current density to drop to 0.470 uA cm-2, meeting the standard set by US Department of Energy. The porosity test also proved that the bipolar plate was impermeable to hydrogen gas. Therefore, this manufacturing method has great potential to be used for the production of sophisticated electrolyzer cell or fuel cell in the future.