A universal modeling and simulation approach for rechargeable lithium batteries is presented in this paper to introduce a practical method to conduct battery pack simulation from accurate cell models that can account for cell imbalance. We used a model based on an equivalent circuit technique commonly used in electrochemical impedance characterizations. Our approach uses parameters deduced directly from cell testing, which promise a convenient integration with live cell monitoring and control circuitry. Such integration accompanied with the generic nature of the model offers the universality in this modeling approach. We began with the explanation of a single cell model which is validated against experimental data to demonstrate its validity of high accuracy. A highly accurate single cell model is essential for the derivation of reliable statistical confidence interval to accurately account for the intrinsic imbalance of the cells in the pack. We then demonstrated that a high fidelity pack simulation can be achieved when such imbalance was accounted for.
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