State‐of‐charge estimation with aging effect and correction for lithium‐ion battery

Abstract

This study proposes Lithium‐ion battery aging correction state‐of‐charge (SOC) estimation techniques. Although the battery is aging, the SOC error estimation system maintains the setting range using a low‐cost 8 bit micro‐controller. The proposed method can track and correct the open‐circuit voltage against capacity in the battery management system by comparing the capacity error with the coulomb counting and look‐up table methods. The experimental results verify that the SOC estimation error is still lower than 3.5% after 1000 cycles. The SOC estimation verification platform verifies the Sanyo UR18650 W lithium battery. After 300 accelerated aging cycle charge–discharge tests, the test results showed that the SOC prediction precision for an aged battery is as high as 2.67%.