Chapter Seven - Fuel Cell Modeling

Abstract

This chapter provides an introduction to fuel cell modeling. Requirements include power and energy requirements, environmental operating conditions, size and volume limitations, and safety specifications. To provide answers quickly, the designer must select a model that balances robustness, accuracy, and computational effort. Physical phenomena occurring within a polymer electrolyte membrane (PEM) fuel cell can in general be represented by the solution of conservation equations for mass, momentum, energy, species, and current transport. Equations that deal specifically with phenomena in a fuel cell are Darcy's equation for fluid flow in conduits and porous media, Pick's Law for diffusion, Stefan–Maxwell equation for multispecies diffusion, Fourier's Law for heat conduction, Faraday's Law for relationship between electrical current and consumption of reactants in an electrochemical reaction, Butler–Volmer equation for relationship between electrical current and potential, and Ohm's Law of electrical current conduction. The set of equations is applied to a computational domain using finite difference, finite volume, or finite element methods. Several examples are used to illustrate the procedure and capability of PEM fuel cell models: Bernardi–Verbrugge model, You–Liu model, two-dimensional above-the-channel model, two-dimensional along-the-channel model, and three-dimensional models. Several CFD software distributors, such as FemLab, FLUENT, and CFD Research (now ESI Group), have developed fuel cell modules that can be used in conjunction with the original CFD codes.