The ever-advancing transformation of the fossil fuel-based energy system towards a sustainable circular economy based on renewable sources is causing an ever-increasing demand for hydrogen as an energy source. The desired hydrogen economy is leading to an increasing number of research projects in the field of hydrogen production, storage and utilization, which means that also the topic of hydrogen production from water electrolysis is constantly gaining importance. In particular, the PEM electrolysis discussed in this thesis offers the potential to assume the leading role in sector coupling between the electrical and gas grid as well as the possibility for the hydrogen supply of fuel cell drives or hydrogen engines in the mobility sector.
In collaboration with AVL, the monitoring of hydrogen production by use of the PEM electrolysis has been investigated throughout this thesis. It is focused on the research of the existing degradation mechanisms that may occur during the operation to develop a new diagnostic tool for degradation monitoring that can be used to provide information about the PEM electrolyser. Given to the enormous complexity of such a monitoring system, an initial knowledge base for the further development of the diagnostic tool is being produced in this thesis. For this purpose, the thesis is divided into two sections, the technical and the development part.

In the beginning, the technical section is dedicated to the general technological basics of electrolysis, followed by the specialization in the PEM electrolysis technology and ending with their occurring degradation mechanisms. The subsequent development part initially presents a physical modeling approach that captures the transport mechanisms during the operation of an electrolyser. This is followed by the determination of the most important influencing factors on degradation monitoring by identifying the so-called “stressors” and categorizing them into the four main categories: Thermal, Hydration, Mechanical and Potential. These operational stressors represent the events that trigger the stress situations during the operation and are required for the creation of the so-called “Failure-Fingerprint trees” for the main components of the PEM electrolyser.
In the end, these flowcharts provide an overview of the cause-effect relationship for the individual degradation mechanisms at the component level of a PEM electrolyser and are necessary for tracking and preventing the occurring degradation processes. Additionally, the diagrams also record those events that are usually overlooked during the stress tracking and lead to actual deterioration. The results of these visualizations represent the first starting point for the additional development of the desired diagnostic tool for degradation monitoring.