Research On The SOC Parameter Estimation Of Li-Ion Battery

Lithium-ion batteries as a new form of energy, with a small, self-discharge rate,good rate discharge performance, environmental protection and other advantages toget the community’s recognition and attention, is widely used in digital products,electric vehicles, military, aerospace, energy storage and other fields. Stable andreliable BMS can improve the lithium ion battery cycle life, safety, reliability and costsavings. And accurately estimate battery SOC value is the most basic BMS mostimportant aspect.In this thesis, a company in Tianjin solar street light controller for the study,discussed the characteristics of lithium batteries commonly used in the equivalentcircuit model. Through a large discharge-standing experiments, established asecond-order RC lithium manganese battery model. Based on the analysis of thealgorithm used in the SOC, and items according to the characteristics of thelithium-ion battery system SOC estimation accuracy requirements, the use of the STEKF algorithm to estimate the SOC of the battery, as compared with other algorithms,ST EKF algorithm estimation error small, high accuracy to meet the accuracyrequirements of the project. The paper also built-based DSP chip SOC verificationsystem, and give the software design process of each module. Finally, the actualhardware system test indicates that the system is running well.