State-of-Charge approximation using Coulomb Counting for Lithium Ion Batteries – A Low-cost approach

This paper presents a hybrid method algorithm for accurate and cost-effective State-of-Charge (SOC) approximation in Lithium-Ion batteries. Our algorithm integrates coulomb counting with open-circuit voltage (OCV) correction, achieving precise SOC estimation at a lower cost compared to the fuel gauge IC technique. Since electric vehicles rely heavily on efficient Battery Management Systems (BMS), enhancing SOC estimation accuracy is crucial. Coulomb counting (ampere-hour counting) is widely used for SOC estimation, while OCV correction addresses voltage fluctuations due to temperature and aging, improving precision. Our algorithm corrects inaccuracies in ampere-hour calculations caused by battery leakage, current calibration errors, and minor current consumption from passive elements with the help of OCV. By combining Open Circuit Voltage (OCV) correction with coulomb counting, our approach yields more accurate State of Charge (SOC) estimations and offers an alternative to the traditional fuel gauge Integrated Circuit (IC) technique. This method achieves comparable accuracy with simpler and less complex hardware, making it an efficient solution for SOC estimation.