Study on the transfer phenomena of gas, liquid, heat, and electron in a cell for the development of high performance PEM fuel cell available in low temperature conditions

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This study has been conducted to clarify the mass, heat, electron transport phenomena in gas diffusion layers (GDLs) in fuel cell. Using an optical fuel cell, temperature distribution in cathode channel and current density distribution in anode channel was investigated. The experimental results showed that there is good correlation between the temperature distribution and the current density distribution, and uniformity of the contact pressure strongly influences the temperature and current density distributions. The observation result indicated that there is a condition when gas paths are established deep in the gas diffusion layer in flooded condition, suggesting a possibility to legalize good performance with utilizing this phenomenon.In PEFC at low temperature, the freezing of produced water induces the extreme deterioration of cell performance. To clarify the freezing phenomenon and influencing factors of freezing in PEFC, experimental attempts were conducted. The results showed t … More hat the water initially diffuses back into the membrane, followed by water production in the surface of the cathode. The initial step is dependent on the water content in the membrane, and it must be controlled to an optimal value before lowering the temperature. It was also shown that the freezing characteristics are different for GDL characteristics. When temperature is lower than -20 deg. C, the frozen layer appears to be formed in catalysis layer.The lattice Boltzmann method was applied and the two-phase flow in the separator-channels was simulated to understand the behavior of condensed water in PEMFC. The projection method was used for the large density difference between liquid and gas. Further, the wetting potential was introduced into the boundary conditions to consider the effect of wettability on the water behavior. It demonstrated the difference in the water removal motion for the different configurations and wettabilities of channels. The method can be a powerful tool for the simulation of two-phase flow in fuel cells. Less