Development and validation of a quasi-2D electrolysis stack model with a focus on dynamic thermal behavior

Maintaining a constant stack temperature and minimizing temperature gradients within the stack during oper ation is critical to the efficiency and durability of proton exchange membrane (PEM) electrolyzers. At the same time, the significant amount of heat released during operation provides opportunities to reuse this heat, potentially improving economic efficiency and contributing to the decarbonization of the heating sector. The design of stack temperature and heat recovery control systems requires accurate and effective models that describe the dynamic thermal behavior of the stack during load changes without being overly computationally intensive. Therefore, this paper presents a dynamic quasi-2D model of a PEM electrolysis stack that rapidly calculates these dynamic processes in a generally applicable manner. The model also incorporates phenomena such as gas and liquid crossover and pressure drop. We validated the performance of the model with experi mental data from a PEM electrolysis test bench and demonstrated its accuracy in describing the electrochemical and dynamic thermal behavior. The stack voltage was simulated with a mean absolute deviation (MAD) of 0.0895 V and the anode outlet temperature with an MAD of 0.127 K, while the simulated time constants of the thermal step responses showed an MAD of 4.06 %.