Fabricating High-Aspect Ratio Microchannels on Metallic Sheets Using Hydroforming

Abstract

High-aspect ratio microchannels on bipolar plates have the advantage of improving fuel cell performance. This study formed high-aspect ratio microchannels by increasing the forming pressure, and predicted excellent aspect ratio of micro-flow channels by optimization analysis during the hydroforming process. This study used an experimental high-pressure hydroforming apparatus that provides various pressures to form microchannels on 304 stainless steel sheets with 0.1 mm thickness. Simultaneously, finite element analysis software was used to analyze the hydroforming process. First, the precision of the finite element model was verified by comparing simulations with experiments. Subsequently, the optimization software was connected to the finite element software to determine the optimal aspect ratio of microchannels by changing the dimension of micro-flow channels and pressures. Furthermore, the results of the simulations, hydroforming experiments, and related literature were discussed. The result indicated that the high-pressure hydroforming technique was feasibility, which formed high aspect ratio microchannels with 200 MPa, and the optimization predicted aspect ratio could reach 0.478 when changing geometries of channels and pressures. This research proposed a design process through hydroforming experiments, finite element analysis, and optimization analysis when predicting and designing the dimensions of micro-flow channels on metallic bipolar plates.