An Approximate Analytical Model for

The characteristics of a Zinc/Air (Zn/Air) primary cell are discussed. In addition, current technologies and the corresponding electrical performance are introduced. The basic principles of operation of a Zn/Air primary cell are discussed, focusing on the anode, cathode, and electrolyte. Basic kinetic and transport expressions are developed for the two main components of the cell: the anode and cathode compartments, based on which an overall formula for the cell polarization is developed. Input parameters are selected and approximated where possible to observe the model’s ability to predict potential versus current density. Time-dependent anode performance is accomplished through the use of the shrinking core reaction model for the discharge of the zinc particles. The time-dependent dimensionless radius of the zinc particle (ξ) is then used in conjunction with the developed transport and kinetic expressions for the prediction of the overall cell performance as a function of time. Plots of cell voltage prediction versus time and percent capacity versus time are presented. The simulations indicate an adequate approximate analytic model valid for a variety of drain rates corresponding to current hearing instrument devices in the market.