Identification and analysis of key factors affecting performance of PEM fuel cell
Lia Maisarah Umar
Date of Issue2007
School of Mechanical and Aerospace Engineering
Analysis of PEM Fuel Cell performance was conducted by implementing two in-situ non destructive electrochemical assessment methods namely Current Measurement Method and Electrochemical Impedance Spectroscopy. In addition, two novel approaches were introduced to these two basic methods to identify key factors affecting the performance of PEM Fuel Cell. In the first approach, segmented fuel cell was used to assess Parallel, 1-S, and 3-S flow field topologies. The result revealed that topology design affects the cell performance and its distribution over the cell area significantly. Observation of the segment responses on the application of different cell potential (at the range of OCV–0.5 Volt) showed that in the absence of flooding, different parts of the cell undergo similar mechanisms but of different extent. The second approach, Thin Film-Agglomerate Model, was used to differentiate the mechanisms occurring within oxygen and air cells. Both cells experienced performance limitation originating from Faradaic reaction, oxygen diffusion at agglomerate region, and diffusion at thin film region. The appearance of further diffusion limitation in the backing layer exhibited only by the air cell explained the difference between the performance of oxygen and air cell. The last part of this project was devoted to investigate the effect of water management-related factors which is one of the key issues in the performance degradation of the PEMFC. The results showed that reactants humidification (especially at the anode-fuel side) increases the cell performance due to higher water content for higher ionic conductivity of Nafion. Application of back pressure in general leads to higher utilization of the catalyst surface active area and more water condensation for improved proton conductivity.
DRNTU::Engineering::Electrical and electronic engineering::Electric power::Production, transmission and distribution