Thermal performance enhancement of air-cooled proton exchange membrane fuel cells by vapor chambers

In this study, five vapor chambers as heat spreaders are integrated into a 10-cell air-cooled proton exchange membrane fuel cell stack to improve the thermal management of the stack. The evaporation sections of the vapor chambers are embedded in the stack, while the condensation sections are exposed to the environment to release the heat generated in the stack. A series of experiments are performed, and the relevant thermal performance parameters are compared under different operating conditions. The experimental results show that the vapor chambers can enhance the heat transfer and homogenize the temperature within the stack. The maximum temperature difference between the cells at 0.64 A/cm(2) is only 5.3 degrees C, and the temperature gradient within the active area is less than 1.5 degrees C. The results also indicate that the cooling conditions of the condensation sections of the vapor chambers and the air flow rate in the cathode channels have important effects on the thermal performance of the stack. Under proper cooling conditions, the vapor chambers can remove almost half of the heat in the stack. The results of this study demonstrate the feasibility of applying vapor chambers to the thermal management of small-sized air-cooled proton exchange membrane fuel cells.