Numerical Simulation of Primary Zn/MnO2 Batteries Under Continuous and Intermittent Discharge

Abstract

In this work, a multiphase continuum model is developed to simulate discharge behavior of primary Zn/MnO2 alkaline batteries. Both macroscopic and microscopic phenomena are integrated to describe the species diffusion in cell length and particle length scales. The predicted battery performance is validated against experiments under different rates of continuous and intermittent discharge. The model is applied to better understand evolution of internal gradients and local conditions, polarization sources and sensitivity to design parameters. Although accurate point prediction is challenging for small (less than 2%) design changes due to the complexities in reaction chemistries and limitations imposed by model assumptions, predictive modeling has shown to be useful for larger design and experimental changes. For example, the amounts of ZnO precipitation in the separator are predicted through simulation under different discharge protocols to evaluate the risk of internal shorting, and are in good agreement with experimental testing.