Study of hysteresis voltage state dependence in lithium-ion battery and a novel asymmetric hysteresis modeling

The relationship between open-circuit voltage (OCV) and state of charge (SOC) of lithium-ion battery, as an important battery parameter, is widely used in battery state estimation and safety management. However, the hysteresis phenomenon, which makes it difficult to obtain the OCV-SOC curve. Firstly, the hysteresis behavior in ternary lithium battery is studied in detail for temperature, current rate, SOC and charge/discharge path. Based on the experimental data, the dependence of the hysteresis behavior is summarized and analyzed. Finally, an asymmetric hysteresis operator is proposed and a hysteresis model is established to accurately characterize the OCV-SOC relationship of the battery. The model was validated by experimental data with a maximum error of 0.0170 V and an absolute average error of 0.0063 V. The results show that the model can accurately characterize the battery hysteresis effect and has positive effects for battery condition estimation and safety management.