Experimental investigation on PEM fuel cell flooding mitigation under heavy loading condition

Water flooding is a crucial factor affecting the lifetime of a proton exchange membrane (PEM) fuel cell. In this paper, A laboratory-scale (25 cm2) single PEM fuel cell was tested to investigate the characteristics of fuel cell under a load shedding process with various air flow rates. The performance was assessed using output power and electrochemical impedance spectroscopy, while the cathode flooding was identifled using voltage and cathode pressure drop. The results show that reducing the load within a speciflc range can lower the impedance and lessen floods. The results also demonstrate that there is an optimal inlet flow rate interval considering its effect on system efflciency, durability, and water flooding. In addition, a stepped load shedding pattern was proposed to solve the flooding problem of a fuel cell while taking the power demand into account. The effect of load shedding cycle and air inlet flow rate on flooding was evaluated by comparing the flooding severity coefflcient and output power. The results prove that a longer current reduction cycle is more favorable in alleviating flooding problems. The optimal mode for the fuel cell in this paper was determined according to the flooding situation and power variation. Finally, the approach to obtaining the optimal load shedding pattern for other PEM fuel cells system was summarized. The flooding mitigation approach proposed in this paper can be utilized as a guide for developing strategies to extend the life of PEM fuel cells.

Automated summary

In this study, the performance characteristics of a proton exchange membrane fuel cell under load shedding with different air flow rates were investigated. Voltage and cathode pressure drop were used to identify cathode flooding. The results show that reducing the load can lower impedance and lessen floods within a certain range. A stepped load shedding pattern was proposed to solve the flooding problem, and a longer current reduction cycle was found to be more effective in alleviating flooding. The approach to obtaining the optimal load shedding pattern for other PEM fuel cells was also summarized.