Research on battery pack SOC consistency based on the electric-thermal-fluid coupling model

In this study, a temperature-effected second-order equivalent circuit model was established. The model illustrated that the circuit parameters of battery were affected by temperature and SOC. Meanwhile, a simulation model of battery thermal management system based on electric-thermal-fluid coupling was developed. The results indicated that the arrangement of cooling plates affected the temperature difference, causing SOC inconsistency in the battery pack. Reducing the difference in heat dissipation intensity of battery monomers in parallel circuits could effectively improve SOC consistency. With a higher inlet flow rate of coolant, the SOC consistency of battery pack was improved, thus prolonging the service life of battery pack. Furthermore, the non-uniform initial SOC had an obvious influence on the consistency and service life of battery pack, reflected in the significant fluctuation of the maximum SOC difference during the discharge process. Compared with the uniform group, the non-uniform initial SOC increased the average attenuation capacity of the battery pack. The results could contribute to the optimization of battery thermal management systems and the further study of battery pack consistency.