Minimising the effect of degradation of fuel cell stacks on an integrated propulsion architecture for an electrified aircraft

Abstract

Proton Exchange Membrane Fuel Cells (PEMFC) are receiving interest as an electrical source of energy for aircraft propulsion electrification. However, their implementation challenges such as durability, reliability, and the dynamic behaviour of Fuel Cells (FCs) in an integrated hybrid propulsion system have not been fully explored. Currently, most commercial PEMFC stacks have maximum power close to 150kW. To achieve higher power required for aviation, these stacks can be connected in series and parallel to achieve high voltage required for propulsion. Poor design procedure of cells and stacks can cause variation between the stacks resulting in failure and fast degradation of the connected stacks. In this paper the impact of voltage and current drop of one stack, which could be caused by changes in the fuel cell’s individual axillary parts, degradation of the cells within the stack, or faults in the connections and distribution is explored. Upon exploring different configurations, it is found that the arrangements of FC stacks connections could help in reducing the impact of voltage and current variations due to degradation in each stacks. The imbalance stack performance and its effects on the whole energy storage system performance is not fully explored before. It is important to conduct quantitative analysis on these issues before the PEMFC system can be implemented.