State of charge estimation at battery level from multiple cells management

Abstract

Accurate State Of Charge estimations are one of the critical functionalities of Battery Management Systems, whether it is for single-cell batteries or multiple-cells batteries. However, battery-SOCs are usually generalized without any consideration about cell disparities. In this presentation, we propose to define a more relevant battery-SOC by analyzing the already existing studies about SOC estimation for single cell (cell-SOC) and by developing a battery-SOC which takes cell disparities into account. A focus is also done to explore how to link uncertainties of cells estimations and accuracy of the final battery-SOC in order to give reliable information to the user about the charge amount stored in the battery. The algorithm is then implemented for numeric analysis and comparisons.