Research On Electromagnetic Forming Of PEMFC Bipolar Plate

Bipolar plates are important parts of Polymer Electrolyte Membrane Cells (PEMFC) which is the current research focus of clear energy. Here we propose one processing approach of low cost, high efficiency -- flexible-die forming by magnetic pulse to shape metal bipolar plates. The forming characteristics of plate channels and the influence of processing parameters are investigated by combining Finite Element Method with experimental research based on flexible-die forming by magnetic pulse. Characteristics of flexible-die forming by magnetic pulse are addressed by comparing magnetic pulse forming to the traditional flexible-die forming and the rigid-die forming by punching machine.According to the theoretical model of forming system, Finite Element Analysis (FEA) is established using software ANSYS. The thickness distribution and stress cloud contour are illustrated through analysis of FEA model. The maximum thickness reduction happens at the fillet radius region, the stress-strain behavior of plates'flow-field belongs to the plain stress-strain type. The main deformation is bulging while the composite deformation of combining bulging and bending occurs at the fillet radius region. As the max load,load velocity and fillet radius increase, the channel height increases. The hardness of rubber has little effect to the formability under the experiment conditions.The thickness distribution principle and deforming characteristics are verified by magnetic pulse forming with flexible-die experiments. As discharge energy,discharge frequency increase, the channels height increases consequently.The forming results and dimension uniformity of three approaches are compared through experiments and principles below are acquired: firstly, magnetic pulse load can enhance the liability of plates and overweight that of traditional punching method; then, between-plates and in-plates dimension uniformities by magnetic pulse are both more satisfying than those by punching. In conclusion, flexible-die forming by magnetic pulse is an efficient approach to form bipolar plates.