Development of radial flow channel for improved water and gas management of cathode flow field in polymer electrolyte membrane fuel cell

This thesis presents an innovative radial flow field design for PEMFC cathode flow plates. This new design, which is in the form of a radial field, replaces the standard rectangular flow channels in exchange for a set of flow control rings. The control rings allow for better flow distribution and use of the active area. The radial flow field was constructed with aluminum and plated with gold for superior surface and conductive properties. These materials were selected based on the results obtained from the performance of the standard flow channels of serpentine and parallel constructed of hydrophilic gold and hydrophobic graphite materials. The new flow field design provides a competitive performance compared to the current standard serpentine and parallel flow fields in a dry-air-flow environment. The polarization curves for a dry cathode reactant flow, however, shows excessive membrane drying with the radial design. Humidifying the air flow improves the membrane hydration while the fuel cell with the innovative radial flow field produces a higher limiting current density compared to other channel designs, even the serpentine flow field. The water removal and mass transport capacity of the radial flow field was proven to be better than parallel and serpentine. This performance increase was achieved while maintaining the pressure drop nearly half of the pressure drop measured in the serpentine flow fields. The initial results for this design show promising performance and further optimization and simplification of the design should improve the performance and allow for simpler manufacturing processes.Applied Science, Faculty ofEngineering, School of (Okanagan)Graduat