Experimental study of a passive thermal management system using vapor chamber for proton exchange membrane fuel cell stack

To mitigate the parasitic power consumption caused by conventional air and water cooling, this study proposes a novel passive cooling scheme that integrates vapor chambers into proton exchange membrane fuel cell stack for thermal management. A 1.32 mm thick vapor chamber is designed and fabricated, and its heat transfer performance is verified through tests conducted at different powers using a heating pad. After confirming that vapor chambers can meet the heat dissipation requirements, the output characteristics of the stack coupled with vapor chambers, are experimentally evaluated during both fast start-up and steady-state operation. Results demonstrate that the vapor chamber efficiently operates at a heat flux density of only 0.052 W/cm2 at evaporation section, while maintaining a maximum in-plane temperature difference of 2.6 °C at 48 W. During fast start-up loading of the stack from 0 A to 40 A, the vapor chamber exhibits rapid thermal response and excellent temperature uniformity, preventing stack performance degradation due to improper operating temperatures. Compared to a general air-cooled stack, the stack coupled with vapor chambers exhibits a significant 21.7% improvement in stack voltage. These results systematically demonstrate the feasibility of vapor chambers for the thermal management of air-cooled proton exchange membrane fuel cell stacks.