Aging of PEM electrolyzers: influence of fluctuating current supply

Proton Exchange Membrane (PEM) electrolyzers face significant durability challenges due to harsh operating conditions, such as elevated temperatures and high current densities. In addition, several other sources of degradation have been identified, including current ripple from power electronics, dynamic operating conditions, gas bubble accumulation, and frequent start/stop cycles. Recent aging studies on PEM electrolyzers have shown that triangular current ripple at 10 kHz (typically generated by DC-DC converters) constitutes a particularly critical operating condition. This ripple accelerates degradation phenomena such as increased high-frequency resistance, corrosion, and damage to components like the titanium mesh. Addressing these durability issues is essential to enhance the lifecycle performance and cost-effectiveness of PEM electrolyzers. The objective of this work is to investigate the impact of current ripple generated by power converters on the long-term aging of a commercial PEM electrolyzer. This investigation involves monitoring the polarization curve and tracking changes in the parameters of an equivalent PEM electrolyzer model over time. The results demonstrate a significant increase in stack voltage and a growing disparity among individual cell voltages, leading to reduced energy efficiency. Furthermore, parameter estimation before and after aging reveals a notable increase in ohmic resistance.