State of Charge and Equivalent Internal Resistance Estimation for a Multi-cell Application based on Cell-Difference-Model

This paper suggests a stale of charge and equivalent internal resistance estimating algorithm for a multi-cell application in the presence of inconsistencies between cell to cell. The proposed method is devised through the nonlinear-model-based robust state observer and the cell-difference-model-based online parameter identification technique. This method has the following contributions: 1) the average stale of charge is robustly estimated even if there exist inconsistencies between cell to cell, and 2) based on the cell-difference-model and online parameter identification technique, the state of charge and equivalent internal resistance of all cells are identified. Performing the simulation and the experimentation, it is shown that the proposed method provides an accurate state of charge and equivalent internal resistance estimation performance for the multi-cell despite the cell-to-cell state variation.