Modeling and characterization of a lead-acid cell

A mathematical model of a lead-acid cell is developed to study the dynamic behavior of the cell during discharge, rest, and charge. Concentrated binary electrolyte theory and a volume-averaging technique are used to model the transport of electrolyte in the porous electrodes and separator. The model is used to predict profiles of acid concentration, overpotential, porosity, reaction rate, and electrode capacity as functions of time. The model is also used to evaluate the effects of design parameters such as electrode porosity, electrode thickness, separator thickness, and acid reservoir volume and operating temperature on the discharge and charge performance of a lead-acid cell.; A parameter estimation procedure is developed to allow single-electrode models of the positive and negative electrodes to be used along with experimental results to obtain values of the kinetic parameters, which are needed for the cell model. This parameter estimation approach provides a direct way of obtaining values of the kinetic parameters of porous electrodes such as the effective exchange current densities, {dollar}asb{lcub}max{rcub}isb{lcub}o,ref{rcub}{dollar}'s, which can not be obtained with conventional methods using planar electrodes. Finally, the model and the approach used in deriving the governing equations can be used to model other battery fuel cells systems where porous electrodes are utilized.