Warm hydroforming of an aluminium bipolar plate for proton exchange membrane fuel cells

This work aims at finding valid solutions (in terms of manufacturing process, material and typology) for the production of the Bipolar Plate (BP) used in Proton Exchange Membrane Fuel Cells. In particular, the authors investigate the manufacturing of the BP, using an Aluminium alloy (AA5754), by Warm HydroForming (WHF). Different BP geometries (characterised by different channels layouts) were designed and investigated using the Finite Element (FE) approach. At first, the geometrical features of the BP channels (depth and width, distance between adjacent channels) were defined using a two-dimensional geometry derived from the 3D shape of the BP and adopting a Design of Experiment technique. Subsequently, main parameters of the WHF process (temperature, pressure) were defined using three-dimensional simulations: all BP geometries were investigated at different working temperatures. The analysis of FE simulations was focused on the following response parameters: the Die Cavity Filling (DCF%) and the maximum Sheet THinning (STH). The optimal BP geometry among the proposed ones was finally evaluated.