Development of in-plane models for the analysis of dead-ended and anode bleeding operation modes and the cell degradation with carbon corrosion

Official URL: http://risc01.sabanciuniv.edu/record=b2297180 (Table of contents)

Low durability and high cost are main drawbacks against commercialization of the proton exchange membrane fuel cell (PEMFC). The anode-bleeding (AB) operation mode offers a very high hydrogen utilization and cost reduction by eliminating additional components for the recovery of hydrogen in the flow-through mode and avoids the carbon corrosion reaction (CCR), which causes degradation of the catalyst layer and occurs typically when the bleeding rate is set to zero in the dead-ended (DEA) mode. Three-dimensional (3D) models are necessary for the analysis of PEMFCs. However, computational cost of 3D models is extremely high because of the strong nonlinearity due to complex interactions in the cell. In this dissertation, a pseudo-three-dimensional (P3D) two-phase and non-isothermal model is developed to reduce the computational cost and predict the cell performance with high accuracy. Results demonstrate that the P3D model results compare very well with ones from 3D model and experimental data from the literature. The P3D model is used to investigate the effects of geometric and operation parameters on the cell performance under DEA and AB operation modes. Moreover, the bleeding rate is optimized to sustain a stable transient cell voltage without the CCR in the cathode catalyst layer (CCL) while hydrogen utilization is kept at more than 99%. Furthermore, effects of the anode flow field design on the cell performance under the AB operation mode are investigated. Lastly, the P3D model is used to study effects of cell degradation on transport properties of the CCL