Experimental study on the dynamic response of voltage and temperature of an open-cathode air-cooled proton exchange membrane fuel cell

Air-cooled proton exchange membrane fuel cells (PEMFCs) are energy-converting devices suitable for various scenarios. In the present study, the dynamic response of voltage and temperature of an air-cooled PEMFC stack with 75 thermocouples is experimentally studied under different loading and fan-controlling strategies. It is found the larger the ramp increment or step amplitude, the greater the voltage overshoot/undershoot (reaching 5.09 V), the longer the response time (reaching 11.23 s), and the higher the voltage non-uniformity (reaching 20.20 %). Under the same current, the stack generally performs better in the unloading process than in the loading process. Too low (or too high) fan pulse width modulation (PWM) will lead to insufficient (or excessive) cooling capacity, resulting in stack overheating (or water flooding). For the stack studied, a relatively low PWM of 40 % at low current is more suitable, while under a medium or high current a PWM of 60 % leads to better cell performance.