Temperature uniformity improvement of a proton exchange membrane fuel cell stack with ultra-thin vapor chambers

Achieving uniform temperature distribution can provide a significant contribution to proton exchange membrane fuel cell performance and durability. Using heat pipes for temperature uniformity can get a simple system and reduce parasitic power. However, current researches on the effect of heat pipes on the temperature distribution are based on the most common cylindrical tube configuration and heat pipes are not integrated into the actual fuel cell during the experiment. They mostly use a heater to simulate the heat generation of the fuel cell. In this study, 6 ultra-thin vapor chambers with a thickness of only 1.5 mm are designed and used for a 5-cell fuel cell stack to reduce the temperature difference in the plane of each layer. Ultra-thin vapor chamber is a type of heat pipes with the advantages of light weight, geometric flexibility and extremely high thermal conductivity. It can provide an effective measure to make the temperature more uniform. The stack is tested under different placement states and cooling conditions. Test results prove that using ultra-thin vapor chamber can obtain a very uniform temperature distribution. Especially under the forced convection condition, the minimum temperature difference on the cathode gas diffusion layer surface can be reduced to 0.3 K. Note that it is better to avoid placing ultra-thin vapor chambers in the unfavorable placement for heat transfer to improve uniformity. The method of thermal management using ultra-thin vapor chambers offers opportunities for uniform distribution of temperature across a fuel cell and compactness.