Lithium-ion battery state of charge estimation strategy for industrial applications

Abstract

The state of charge estimation of lithium-ion batteries is very important for the safe and reliable operation of the battery pack. In the industry, the ampere-hour integration plus open-circuit voltage strategy is usually used to estimate the state of charge. However, the use of open-circuit voltage is very demanding, requiring several hours. In this paper, a new estimation strategy is proposed, which can calibrate state of charge during battery operation to eliminate the accumulated error of ampere-hour integration. Specifically, when the current of the battery is constant current for a period, or the change is small while charging or discharging, the state of charge can be corrected according to its voltage. The detailed theoretical analysis is given in this paper and an experimental platform is built for testing.