Experimental Study on Cooling Uniformity and Hotspot Suppression Characteristics of Air‐Cooled PEMFC With Fan Configuration

Air‐cooled polymer electrolyte membrane fuel cells (PEMFCs) offer structural simplicity and advantages in compact system design; however, nonuniform thermal management induced by fan‐based cooling can lead to hotspot formation, resulting in increased membrane resistance, performance degradation, and reduced durability. In particular, variations in airflow characteristics caused by different fan configurations directly influence stack temperature distribution and voltage stability, indicating the necessity for systematic experimental and quantitative investigation. Accordingly, this study derives a critical operating temperature based on the temperature–voltage characteristics of an air‐cooled PEMFC stack and applies a scheduled PI control strategy targeting experimentally identified hotspot locations using multipoint temperature sensors to enhance thermal stability. Three cooling configurations including single large fan, dual small fans, and quad small fans were experimentally evaluated in terms of stack voltage performance, fan energy consumption, and temperature distribution. Quantitative assessment was conducted using the Cooling Uniformity Index (CUI) and Hotspot Severity Index (HSI). The results demonstrate that the single large fan provides the most stable voltage performance and superior hotspot suppression under high‐load conditions, whereas the quad small fans configuration exhibits the highest cooling efficiency in terms of average temperature reduction and fan power consumption. In contrast, the dual small fans configuration does not present any significant advantage in either thermal stability or energy efficiency.