Application relevant load cycles for PEMFC component development and hybrid system optimization

Polymer electrolyte membrane fuel cells (PEMFCs) are one of the key technologies for the decarbonization of transportation. In contrast to light-duty vehicles (LDV), durability requirements for heavy-duty (HD) transport applications are challenging. To overcome these difficulties, material improvements must be complemented by optimized operation strategies. Furthermore, specific testing protocols in application relevant conditions are required. Harmonized testing protocols already exist for automotive applications. However, for HD applications, such protocols are still pending, which represents a bottleneck for further development. A semi-empirical model is used in a novel systematic top-down methodology to generate application related power demand cycles in PEMFC of an HD hybrid vehicle is presented and demonstrated in detail for the case of PEMFC in HD transport. The resulting load profile, applicable at single cell and stack levels, is proposed as a starting point for a harmonization of open-source HD load cycling and testing protocols for PEMFC component development. Furthermore, the method is also used to evaluate the impact of the energy storage system (ESS) capacity and of the hybridization strategy parameters on the PEMFC stack power demand dynamic and efficiency; providing up to 2 % efficiency increase and a 50 % reduction in FC load changes.