Numerical Investigation of different Forming Approaches for the Manufacturing of Titanium Bipolar Plates for the Aviation Industry

The challenges of climate change have led to an increased commitment from both industry and government to environmentally friendly technologies. In the aviation industry, goals of CO2 and NOx reduction were implemented in the Flightpath 2050. One way to reach this goal is by using alternative propulsion systems, such as fuel cells. The ecologic feasibility of the hydrogen fuel cell depends heavily on its performance which in turn is largely determined by the power to weight ratio as well as the volumetric flows of reactants conveyed within the cell. In this context, a key component for the performance is the bipolar plate (BPP), as its channel geometry defines the volumetric flows of reactants. To reduce the mass of the bipolar plate, lightweight materials such as titanium are used. This on the other hand leads to challenges in the forming of BPP regarding its quality and safety due to its material properties. In this paper, three different manufacturing methods are investigated numerically regarding their feasibility for the use in bipolar plate manufacturing for the aviation industry. To evaluate the suitability of the regarded manufacturing processes, the results are compared in terms of shape accuracy, material thinning as well as stress states. The three-dimensional simulations showed that hydroforming leads to the highest material thinning compared to rubber pad forming and embossing. The shape accuracy was the highest for rubber pad forming, while the stress states varied just marginal.