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

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%.