LITHIUM ION DYNAMIC BATTERY PACK MODEL AND SIMULATION FOR AUTOMOTIVE APPLICATIONS

In this paper, we introduce a lumped parameter, distributed battery pack dynamic model which allows simulation of the electrical dynamics of all the cells in an arbitrarily configured series/parallel pack typical of those used in automotive applications. The dynamic pack simulator is based on the development of an analytical solution for the dynamic response of a single cell and an analytical development of such elemental solutions into a distributed dynamic pack model which can resolve the dynamics of each cell within the pack. This formulation leads to a computationally efficient simulation tool appropriate for application on large battery packs. This simulation tool is then used to perform Monte Carlo simulations on typical automotive current profiles for packs made of cells with a statistical distribution of parameters. A mild distribution of cell mismatch leads to cell unbalance development and statistical metrics for the growth unbalance, presented and related to both current severity and cell parameter distribution. The tool is ideally suited for studies in Battery Management System (BMS) algorithm development, as well as model-based fault propagation and diagnostics.