A practical PEM fuel cell model for simulating vehicle power sources

The interest in fuel cell technology as an alternative to internal combustion engines is growing rapidly with the increased concern with environmental issues such as reducing vehicle emissions. Fuel cells offer a power source which produces electrical energy from fuel and oxidant which produce little or no emissions. Fuel cell power sources are being considered for both terrestrial and marine applications. The research and commercialization of such systems require system modelling to determine performance levels and fuel and oxidant requirements. A practical model will have to be flexible in its calculations depending on the information available. A model predicting the performance of a proton exchange membrane (PEM) fuel cell has been developed for a Ballard Mark V 5 kW 35-cell stack. The parametric model combining both empirical and mechanistic qualities was developed to calculate the cell voltage output in terms of complex relationships between current, stack temperature, and inlet partial pressure of hydrogen and oxygen. The model utilizes an iterative computer solution to obtain a practical flexible model which could calculate any variable in terms of the others. This paper illustrates the use of a practical model to determine the fuel and oxidant requirements to achieve various levels of power required for different vehicle power supplies. Applications to automobiles, buses, locomotives, ships, submarines, and unmanned underwater vehicles with power supplies of 3-3000 kW were investigated