Voltage current curve of a PEM fuel cell:
Research Center "Juelich",, DE
Keywords: PEM Fuel cell
First we consider 1D problem of the cathode catalyst layer (CCL) performance. The general solution is presented and simple analytical formulas for CCL polarization voltage are obtained. Based on these formulas we build a simple fitting equation for voltage current curve of a cell. All terms in this equation have clear physical meaning; coefficients are expressed in terms of basic transport and kinetic parameters.
Then we describe quasi-3D numerical model of PEM fuel cell, equipped with long channels for feed gases supply. The model is based on 2D mass and charge conservation equations in a cell cross-section, coupled by equations for along-the-channel concentration of feed gas. Typical example of "fuel cell map" (distribution of parameters in a cell cross section) is presented.
Finally, analytical and numerical models are used to analyze real experimental voltage current curve. This procedure gives kinetic and transport parameters of the cell and allows to isolate the contribution of 2D effects to voltage loss. A perspective to characterize membrane-electrode assemblies and flow fields, using voltage current curve is discussed.
NSTI Nanotech 2003 Conference Technical Program Abstract