Optimizing PEM fuel cells: Strategies to address local reverse polarity issue

The reversal of polarity in proton exchange membrane fuel cells (PEMFCs) can lead to severe degradation, ultimately compromising safety risks. For this reason, anti-reversal materials and optimizing operating strategies to prevent reversal are developed to prevent overall reversal in PEMFC. However, even with these methods, local reverse polarity (LRP) can still occur and is difficult to identify during PEMFC operation, despite the fact that overall reversal has not occurred. If localized reversal is not promptly identified and addressed with effective measures, it can trigger unpredictable severe damage. This study investigates the characteristics and underlying mechanisms of LRP in PEMFCs. To address the issue of LRP, an innovative anode-cathode temperature differentiation strategy is introduced. Unique temperature controls for electrode optimize reactions, reduce the risk of LRP, and enhance fuel cell performance. It released that cathode at 70 °C and anode at 50 °C eliminates polarity reversal within 180 s, compared to a uniform 50 °C. Moreover, an anode-cathode pressure difference method is proposed. By setting anode at 80 kPa and cathode at 60 kPa results in a 71.1% reduction in polarity reversal current density and a 65.2% decrease in affected area. Lastly, acknowledging water management's importance in preventing LRP, the study refines the gas feeding to better distribute water in PEMFCs. Using a bottom-inlet anode design, there's a 10% reduction in maximum polarity reversal current density and a 9.4% increase in voltage.