Parametric Study of a Single Cell PEM Fuel Cell

Fuel cell systems continue to be one of the most attractive devices for clean power generation, especially when hydrogen is used as the fuel. Their high efficiency and low emissions have made it a candidate for powering the next generation of electric vehicles. Their modular design and scalability makes them prime candidates for a variety of applications. The main impediments to commercialize it are the lack of infrastructure and the production costs. An important issue to reduce the cost of PEMFC system is the design optimization. However, the optimization requires a solid understanding of the underlying physical principles in the fundamental processes that take place in PEMFC. Modeling and Simulation have become increasingly important tools to aid our understandings of these complex physical principles involved in PEMFC by providing a detailed information that is difficult to obtain in experiments, such as local species concentrations, current density profiles.In this way a 3D single cell model of a proton exchange membrane fuel cell (PEMFC) was developed using a computational fluid dynamics (CFD) package (Fluent 6.2.16). This model allows one to evaluate a PEM fuel cell under different operating conditions. These include: gas inlet pressure, gas concentration, humidity and temperature. Simulations were analyzed and validated against literature and experimental data, using the polarization curves. The parametric study revealed that proton exchange membrane fuel cell performance depends on the channel configuration and other thermodynamic parameters. Moderate changes in flow rate, humidity and temperature increases the concentration of hydrogen and oxygen at the electrodes, obtaining high density currents and maintaining the membrane hydrated. Particularly the fuel cell should be operated at 100 % of humidity, 80 - 100°C of temperature and 20 - 25 cc/min of flow rate but this last parameter will depend of dimensions and type of fuel cell. The single cell model provides a clear understanding on how changes in the operating conditions affect the cell performance.