A novel low-cost online state of charge estimation method for reconfigurable battery pack

High precision state of charge (SOC) estimation in battery packs is an integral and important part of battery management and maintenance in various applications ranging from smart grid battery energy storage systems to Electric and Hybrid Electric Vehicles (EV/HEV). In practice, measuring voltage of battery cells in a noisy environment will lead to erroneous SOC estimation, thus compromising the management and performance of the entire battery system, especially when sensors with large drifting rates are used to lower the costs of the battery management system. Therefore, in this study, based on our previous work on adaptive reconfigurable battery networks which can carry out online Open Circuit Voltage (OCV) measurements in microseconds by using a low cost voltage sensor, we propose a low cost online SOC estimation method by exploring the one-to-one mapping relationship between OCV and SOC. Experimental data collected from the real testbed indicate the correctness and robustness of the proposed method. Furthermore, the proposed method is applicable to different types of battery cells in terms of capacity and electrochemistry.