Fuel cell size and weight reduction due to innovative metallic bipolar plates: technical process details and improvements

In the automotive field the application of electric propulsion systems based on fuel cells requires a constant and continuing research of several optimized solutions, especially in terms of weight and size reduction. These key-factors tend to influence significantly the performance of the vehicle where the system is installed on. The main objective of the paper is to obtain breakthroughs in design, manufacturing and assembling a fuel cell stack through the development of innovative metallic bipolar plates, that allows to set up high power density stacks, by lowering sensibly weight and size. The research activity carried out by the aforementioned authors is focused on the choice of suitable materials and the development of optimized tools, processes and techniques, in order to be able to move rapidly towards thinner bipolar plates, with new compact geometries that ensure the required stack output power. The basic idea of the paper consists in highlighting all the detailed operations that take part in the metallic bipolar plate stamping process, from the design to the real production. The current state of the art of metallic bipolar plate consists in 0.20mm thick formed metal sheet that meets the classic requirements settled for this kind of components (highlighted afterwards in the text) and that allows to achieve satisfactory performance of the stack, namely 0.4-0.6 kW/kg, with the large goal of obtaining specific power of about 2 kW/kg. In parallel with the development of metallic plate, the research is currently focused on integrating the gaskets directly on the plate itself, and evaluating different feasible way of connecting the two half plates, the latter being necessary to ensure a suitable system cooling.