Investigations into intermediate temperature polymer electrolyte fuel cell gas diffusion layers: when science meets art

摘要

Polymer Electrolyte Fuel Cells (PEFCs) are a key technology to secure the future of the automotive sector. PEFCs are advantageous due to their low operating temperature (60-80 (^o)C), quick start up times and responsiveness to load change. However, the requirement for expensive platinum, difficulty of water management and heat dissipation means that further improvements are required. One way of reducing the impact of these challenges is to increase the cell operating temperature to above 100 (^o)C. In particular by operating the cell at 120 (^o)C, labelled as the Intermediate Temperature (IT)-PEFC, it becomes theoretically possible to simplify water and thermal management. In order to realise these benefits, further research is required into components of the Membrane Electrode Assemblies (MEAs).ududIn this work, fundamental properties of the GDL have been investigated such as the influence of porosity on electronic conductivity, the influence of the microporous layer, the influence of hydrophobicity and the influence of GDL thickness. This has been done using a mixed methods approach consisting of simulation and experimental work. MEAs were simulated and hand-painted to test the GDL material properties. From this, recommendations for an ideal GDL for intermediate temperature conditions are suggested, for example, using a GDL with; a porosity of 40%, a permeability greater than 10(^-)(^1)(^0) m(^2), an MPL, hydrophobic treatment and as thin as possible. The possibility of using metallic GDLs was also investigated using simulation and experimental work. It was found that metallic GDLs do show better mass transport properties however further work is required to overcome the higher contact resistance.