Series-parallel grouping modeling simulation and experimental analysis of zinc-nickel single flow batteries

Abstract

This study investigates a battery system with a zinc-nickel single flow battery (ZNB) stack by a series-parallel-connected system based on a two-order Thévenin equivalent circuit model for single-cell stack and parameter identification of the experimental model. Two single-cell stacks are simulated with three kinds of series-parallel battery pack equivalent circuit models, and compared with the experimental data. The results show that the simplified equivalent circuit model can accurately characterize the voltage of discharge for the series-parallel battery pack. The relative errors of the series/parallel battery pack are 0.8% and 0.71%. Furthermore, the simulation and experimental test data of the large-scale series-parallel system are compared, thereby indicating that the simplified equivalent circuit model of the series/parallel battery based on the two-order Thévenin model can provide a high-precision prediction for the external characteristics of a large-scale ZNB energy storage system.