Real‐Time Flooding Diagnosis for Dead‐Ended PEMFCs Under Dynamic Loads Using Current Density Distribution

Water flooding severely degrades the performance and lifespan of proton‐exchange membrane fuel cells (PEMFCs), impeding their large‐scale application. A water flooding diagnostic approach is proposed based on the uniformity of current density distribution. This is achieved by employing a dead‐ended PEMFC equipped with a 36‐subarea current density detection plate for high‐accuracy positioning. Experimental results demonstrate a positive correlation between the standard deviation (SD) of current density distribution and cell water content, following the linear equation y  = 0.093 x  + 59.22 ( R ²  = 0.955). Comparative tests show that constant voltage mode stabilizes water content at 78% ± 2% and SD at 380 ± 5 mA/cm ² to suppress flooding, whereas constant current mode leads to excessive water accumulation (92.2%) and a sharp SD surge to 619.0 mA/cm ² , causing voltage collapse. Temperature tests (30–60 °C) confirm that elevated temperatures increase the visible water content inside the cell due to the condensation of water vapor, thereby enhancing current density inhomogeneity. This study establishes SD as a quantitative indicator for flooding severity, enabling precise localization of local flooding and providing critical guidance for PEMFC water management optimization.