The objective of this study is to use multidimensional/multiscale/multiphase polymer electrolyte membrane fuel cell (PEMFC) model [1-10] to enhance understanding of water transport inside gas diffusion layer (GDL) and microporous layer (MPL) during fuel cell operations. The outcomes of this work will improve the development of a fuel cell stack and electrochemical cells with increasing in performance at high current densities. Experimental investigation of oxygen transport has been limited by an inability to resolve water saturation-dependent properties. This work also shows the successful in development of a multiscale calculation technique that incorporates detailed structure of each scale dimension in every component of a fuel cell and simultaneously performed a prediction. The effect of operating conditions and GDL/MPL properties on the transports including liquid water inside PEMFC will be the primary focus of this work.

Figure 1 shows an example of simulation works to predict the effect of MPL thermal properties on liquid water transport and performance of PEMFC. In this figure, three specific thermal conductivities were simulated. Figure 1 shows liquid distributions at cathode side of PEMFC using SGL 25BC GDLs. The amount of water condensation increases from low thermal conductivity to high thermal conductivity and the condensed water starts from the areas under the rib instead of the areas under the channels. This is because the areas under the rib has lower temperature than the areas under the channel. This figure also presents the local liquid saturation profiles inside GDL/MPL. The higher liquid saturation profiles are presented in MPL (Locations 5 and 6) than in GDL (Locations 1 to 4). In the particular operating condition, the performance increases when the thermal conductivity is higher. This simulation shows a possibility of model based engineering to optimize MPL thermal property and operating conditions.

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