Multi-Physics Pinhole Size Tolerance Analysis on the Leakage Characteristics and Performance of Proton Exchange Membrane Fuel Cells

This study delves into exploring how pinhole size affects both the electrochemical efficiency and hydrogen leakage within proton exchange membrane fuel cells (PEMFCs). The researchers devised a comprehensive multiphysics field model for the PEMFC and employed the finite element method to simulate various pinhole diameters, evaluating their impact. Our findings highlight that the influence of pinholes on fuel cell performance heavily relies on the inlet pressure. When maintaining a constant inlet pressure, pinholes smaller than 0.37 mm diameter exhibit minimal impact on fuel cell performance, maintaining hydrogen utilization rate above 90%. Conversely, the pressure disparity across the membrane notably amplifies hydrogen leakage rates, leading to reduced current density due to the oxidation of escaping hydrogen. Consequently, this decline affects hydrogen and oxygen concentrations downstream of the pinhole. Specifically, sustaining a 90% hydrogen utilization rate necessitates a pinhole diameter of 0.027 mm at an inlet pressure differential of 500 Pa. Establishing the acceptable pinhole size crucially informs the operational strategy for PEM fuel cells.