Performance analysis of coulomb counting approach for state of charge estimation

Document Type

Conference Proceeding

Publication Date


Publication Title

2019 IEEE Electrical Power and Energy Conference, EPEC 2019


battery fuel gauge, battery impedance, Battery management system, equivalent circuit model, state of charge, state of charge estimation


In this paper, we consider the problem of the state of charge estimation for rechargeable batteries. Coulomb counting is one of the traditional approaches to SOC estimation and it is considered one of the reliable approaches to SOC estimation as long as the battery capacity and initial SOC is known. However, the Coulomb counting method is susceptible to errors and the extent of these errors are not studied in the literature. In this paper, we formally derive and quantify the SOC estimation error due to the following four types of error sources: (i) current measurement error; (ii) error due to the approximation of current integration with respect to time; (iii) uncertainty in the knowledge of battery capacity; and the (iv) error (drift) in timing oscillator. We analyze the individual effect of these four types of errors on the estimated SOC. Further, We show numerical simulations to illustrate the effect of these errors on the estimated SOC.