Influencia de la orientación en el campo gravitatorio y placas bipolares en la fenomenología oscilatoria bajo condiciones de deshidratación en el cátodo en PEFC

Kurzfassung

Oscillatory fluctuations of a single proton exchange membrane fuel cell appear upon operation with a dry cathode air supply and a fully humidified anode stream. Periodic transitions between a low and a high current operation point of the oscillating state were observed [1] where the oscillation amplitude is the principal parameter which characterizes the change of membrane water content. The oscillations are caused by periodic flow type changes from one to two phase flow in the anodic channels of the flow field. It has been observed that cell orientation with respect to earth’s gravity field influences the liquid water distribution in the anodic flow channels and thus it is also affecting the oscillatory behavior of the cell performance. Comparing cell performance oscillations with a five channel serpentine flow field to a cell with one channel serpentine it is found that the oscillating performance behavior is also influenced by the gas velocity within an anodic flow channel