Theoretical and Experimental Study of a Fuel Cell Stack Based on Perfluoro-sulfonic Acid Membranes Facing High Temperature Application Environments

Elevating the operating temperature of fuel cell stacks based on perfluoro-sulfonic acid (PFSA) membranes is crucial for simplifying their cooling system and enhancing power density. In this study, we used a semiempirical model to correct the conductivity of the PFSA membrane at high temperatures and analyzed the impact of elevating the operating temperature and inlet pressure on the output performance, voltage consistency, internal water content, and dynamic response of a 10 kW rated power fuel cell stack. The results show that increasing the operating temperature leads to a significant decrease in the output performance of the stack, resulting in poor voltage consistency, large voltage fluctuations, and overshooting during the dynamic response. To mitigate the impact of higher temperatures on the saturated vapor pressure, increasing the inlet pressure of the stack can effectively improve the output and dynamic performance. Similarly, the net water drag coefficient (αNWD) can be used to characterize and monitor the water transport process within the fuel cell. Its value is positively correlated to the operating temperature and inlet pressure. Increasing humidity on the cathode side promotes water back-diffusion, thereby improving the high-temperature operation of the stack.