Battery State of Charge Estimation Error Comparison Across Different OCV-SOC Curve Approximating Methods

Abstract

Accurate estimation of Rechargeable Batteries Parameters, such as State Of Charge (SOC), contributes to their safety and reliable operation in a wide variety of applications (e.g. automotive, stationary energy storage, medical equipment, among others). Due to variations in environmental and load conditions, battery cells and their instrumentation devices can experience deviations from their standard operation values, leading to an imprecise measurement of State Of Charge (SOC) indicator variables. Then, SOC estimation models are required. These estimations developed through analytical models consider intrinsic battery chemistry variables and operation cycle conditions are taken from charge and discharge testing; where hysteresis phenomena, measurement, and theoretical adjustment errors can be identified over Open Circuit Voltage (OCV)-SOC curves. This study compares the model adjustment errors of several estimation methods, taken from literature to approximate the OCV-SOC curves of a rechargeable battery pack.