Investigation into the performance and acoustical characteristics of proton exchange membrane fuel cells

Over the last three decades, much research has been conducted into developing fuel cells (FCs) owing to their high efficiency and environmental friendly operation. Among different types of FCs, proton exchange membrane fuel cells (PEMFCs) are popular for stationary and mobile applications. They have a high-energy density, low operating temperatures, quick start-up times and zero emissions. However, their low reliability and unacceptable high costs limit their wider adoption in the above-mentioned applications. Lack of understanding and complexity of FC operations, mechanical failure, and the lack of root cause analysis and prevention techniques are obstacles that stand in the way of improving such low durability and reliability. The aim of this PhD work is first to derive a realistic model that represents the complex operations of a single PEMFC and experimentally verify the effectiveness of the developed model. Second, to gain a clear understanding of PEMFCs’ failure modes and effects analysis. Third, to assess the detectability of commonly used monitoring techniques and explore the acoustical characteristics of PEMFCs under normal and faulty conditions. Power parameters are directly affecting the operating conditions of PEMFC and hence are expected to carry useful information about their conditions. Unfortunately, those measurements are intrusive and they do not detect faults at the early stages of onset. However, PEMFCs are dynamic chemical systems that involve phase transitions and thus are acoustically active. Chemical changes during interactions are usually accompanied by a transfer of energy and part of energy may be converted to an acoustic emission (AE). Although, AE techniques are widely adopted for monitoring chemical and electrochemical systems, no rigorous work has undertaken to characterise the acoustical behaviour of PEMFCs. Therefore, the nature and source of AE in PEMFCs are identified and effect of load variations on them are experimentally investigated as part of this study. It is anticipated the work presented in this thesis will open the door for more studies to build non-intrusive robust diagnostic systems, which will contribute to enhance the reliability of PEMFCs.