Dimensioning Lithium-ion Battery Packs and Fuel Cells for Hybrid Power Systems

Energy storage using hydrogen is a key aspect of the energy transition. By means of fuel cells, the stored chemical energy can be converted again to electrical energy. Fuel cells have the advantage that the energy density is significantly higher, when compared to battery energy storage. Furthermore, the hydrogen storage container can be sized independently from the fuel cell itself, which simplifies the system design. However, a typical problem with fuel cells is the slow dynamic behaviour. For systems with fast transients, typically an auxiliary power source will be required, which in turn complicates system design. This paper presents a methodology to dimension the auxiliary power source based on a given load profile. The algorithm is then applied to three industrial case studies, thereby highlighting large differences between the applications.