Degradation modelling and reliability analysis of PEM electrolyzer

Reliability is critical to enable the safe production of hydrogen as fuel. Efficient hydrogen production depends on the reliability of electrolytic cells termed an electrolyzer. The polymer electrolyte membrane (PEM) electrolyzer is one of the most promising hydrogen production technologies. However, hydrogen solubility, diffusivity, and partial pressure differences between the flow channels could affect the reliability and safety of the PEM. The operating conditions could also introduce safety issues inside the PEM electrolyzer due to membrane degradation or thinning. A degraded membrane will initiate the hydrogen produced at the cathode, tends to cross over to the anode and may cause an internal explosion should the mixture of hydrogen-oxygen get minimum ignition energy. Therefore, investigating hydrogen gas cross-over is - imperative to ensure the reliability and safety of the PEM electrolyzers. This paper presents a novel reliability model of PEM electrolyzers, considering readily observable variables relevant to the issue. The Bayesian structural equation defines the causal relationships to variables representing failure scenarios: membrane drying and hot spot formation. The study identifies that the current density and the quantity of water at PEM's anode are two critical variables responsible for the reliability of the PEM electrolyzers. Monitoring and managing these variables will help ensuring PEM's operational safety and reliability.