Hydrogen fuel cells have the potential to dramatically reduce emissions from the energy sector,
particularly when integrated into an automotive application. However, there are three main
hurdles to the commercialisation of this promising technology; one of which is reliability. Cur-
rent standards require an automotive fuel cell to last around 5000 h of operation (equivalent
to around 150,000 miles), which has proven difficult to achieve to date. This hurdle can be
overcome through in-depth reliability analysis including techniques such as Failure Mode and
Effect Analysis (FMEA), Fault Tree Analysis (FTA) and Petri-net simulation. This research
has found that the reliability field regarding hydrogen fuel cells is still in its infancy, and needs
development, if the current standards are to be achieved. In this research, a detailed reliability
study of a Polymer Electrolyte Membrane Fuel Cell (PEMFC) is undertaken. The results of
which are a qualitative and quantitative analysis of a PEMFC. The FMEA and FTA are the
most up to date assessments of failure in fuel cells developed using a comprehensive literature
review and expert opinion.
Advanced modelling of fuel cell degradation logic was developed using Petri-net modelling
techniques. 20 failure modules were identfied that represented the interactions of all failure
modes and operational parameters in a PEMFC. Petri-net simulation was used to overcome key
pitfalls observed in FTA to provide a verfied degradation model of a PEMFC in an automotive
application, undergoing a specific drive cycle, however any drive cycle can be input to this
model. Overall results show that the modeled fuel cell's lifetime would reach 34 hours before
falling below the industry standard degradation rate of more than 5%. The degradation model
has the capability to simulate fuel cell degradation under any drive cycle and with any operating
A fuel cell test rig was also developed that was used to verify the simulated degradation.
The rig is capable of testing single cells or stacks from 0-470W power. The results from the
verification experimentation agreed strongly with the degradation model, giving confidence in
the accuracy of the developed Petri-net degradation model.
This research contributes greatly to the field of reliability of PEMFCs through the most
up-to-date and comprehensive FMEA and FTA presented. Additionally, a degradation model
based upon Petri-nets is the first degradation model to encompass a 1D performance model to
predict fuel cell life time under specific drive cycles.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.