Optimization, Design, and Manufacturing of New Steel-FRP Automotive Fuel Cell Medium Pressure Plate Using Compression Molding

In this work, a new plastic-intensive medium-pressure plate (MPP), which is part of a fuel-cell system, has been developed together with a steel plate meeting all mechanical and chemical requirements. This newly developed MPP had to achieve the objective of saving weight and package space. The use of compression molding as a manufacturing technique facilitated the use of glass mat thermoplastics (GMT) which has higher E-modules and strength compared to most of the injection molded materials. A steel plate was placed as an insert to help achieve the stiffness requirements. For the development, the existing MPP was benchmarked for its structural capabilities and its underlying functional features. Four different FRP materials were investigated in terms of their chemical and mechanical properties. PP-GMT material, which has both high mechanical performance and resistance against chemicals in the fuel cell fluid, had been chosen. Using the properties of the chosen PP-GMT material, topology optimization was carried out based on the quasi-static load case and manufacturing constraints, which gave a load-conforming rib structure. The obtained rib structure was utilized to develop the final MPP with adherence to the functional requirements of MPP. The developed plastic-intensive MPP exhibits a 3-in-1 component feature with a 55% reduction in package space and an 8% weight reduction. The MPP was virtually analyzed for its mechanical strength and compared with the existing benchmark values. Finally, a press tool was conceptualized and manufactured to fabricate the new plastic-intensive MPP, which was tested in a rig and validated in the FE model.