Monitoring of ageing campaigns of PEM fuel cell stacks using a model-based method

Nowadays, Proton Exchange Membrane Fuel Cells (PEMFC) are considered as a promising solution for transportation applications, especially for the aeronautical field in the context of development of a “More Electrical Aircraft”. Due to various operating conditions, the State of Health (SoH) of a Proton Exchange Membrane Fuel Cell (PEMFC) could be degraded implying a possible decrease of its performance and durability. Hence, there must be a development of tools dedicated to the PEMFC diagnosis and ageing monitoring. In this context, this paper introduces a model-based method contributing to the monitoring of the SoH of a PEMFC in aircraft applications. The proposed methodology consists of the tracking of the temporal evolution a chosen Quasi-Static (QS) model parameters, these parameters being associated with the various physicochemical phenomena involved in a Fuel Cell (FC): activation, diffusion and ohmic. Parameters of the model are identified from a measurement regularly carried out throughout the fuel cell life: the polarization curve (V–I curve). The present model uses also high-frequency resistance measured via Electrochemical Impedance Spectroscopies (EIS) performed at various current values of the polarization curve. This methodology is evaluated here in the framework of three ageing campaigns carried out with three 1 kW PEM stacks operating at low temperature (50 – 80 °C). In this paper, a particular attention is paid to calculations and results relating to the first ageing campaign. A comparison of the results related to the three campaigns is achieved as a part of this work. In addition to the good reproduction of experimental data and the separation of losses in the static domain, the QS model presented in this paper makes it possible to monitor the FC SoH via the follow-up of losses and their related parameters.