Implementation of an Improved Coulomb-Counting Algorithm Based on a Piecewise SOC-OCV Relationship for SOC Estimation of Li-IonBattery

Abstract: Considering the expanding useofembedded devices equipped with rechargeable batteries, especially Li-ionbatteries that have higher power and energy density, the battery management systemis becomingincreasingly important. Infact, theestimationaccuracy of the amount of the remaining charges is critical as it affects the device operational autonomy.Therefore, the battery State-Of-Charge (SOC) is defined to indicate its estimated available charge. In this paper, a solution isproposed for Li-ion battery SOC estimation based on an enhanced Coulomb-counting algorithm to be implemented formultimedia applications.However,the Coulomb-counting algorithm suffers from cumulative errors due to the initial SOC andtheerrors ofmeasurements uncertainties,thereforeto overcome these limitations,we use the Open-CircuitVoltage (OCV),thushavinga piecewise linear SOC-OCV relationship andperformingperiodic re-calibration of the battery capacity. Thissolutionis implementedand validated on a hardware platform based onthePIC18F MCU family. The measured resultsarecorrelated withthetheoretical ones; they have shown a reliable estimation since accuracy is less than 2%.