Influence of cathode air supply mode on the performance of an open cathode air-cooled proton exchange membrane fuel cell stack

Open-cathode air-cooled proton exchange membrane fuel cells (PEMFCs) simplify conventional cell stacks' cooling and air supply systems, effectively reducing additional energy consumption and improving portability and reliability. As an air fan provides the cathode reaction gas, different air supply conditions significantly influence the output performance of the air-cooled PEMFC stack. This study used a cathode air supply with exhaust and blow modes to investigate the stack performance under different operating conditions. Compared with the exhaust air supply mode, the stack output voltage in the blow-flow mode increased by 5.5 %, and both voltage and temperature uniformities were improved, with 43.0 % and 23.9 % reductions in standard deviation, respectively, when the current density was 300 mA/cm². In addition, the effect of ambient temperature on stack performance was investigated. Comparing the stack's performance at 15℃ and 30℃ ambient temperatures, the higher ambient temperature increased the stack's voltage, but led to worsening non-uniform temperature distribution. In the air-cooled PEMFC stack, the influence of the heat generated by the fan on the air-cooled stack temperature could not be ignored. The air supply in the blow-flow mode transfers heat to the stack. At a lower ambient temperature, the temperature increase in the stack was more evident under the exhaust air supply mode.