The Analysis of Mathematical Models of Charge-Discharge Characteristics in Lithium-Ion Batteries

This article is devoted to the analysis of mathematical models of the charge-discharge characteristics of lithium-ion batteries. A review of existing equivalent circuits and mathematical models of lithium-ion batteries is presented. The discharge characteristics of a real NCR-18650b battery were obtained during discharge with current value (0.2C, 1C, and 2C). The results of a study of the thermal regime of the battery are presented, which show the battery overheating above the permissible value. The structure and mathematical model of the Battery library block in Matlab Simulink are described. The simulation of the NCR18650b battery discharge process in the Matlab package was performed at the same discharge currents. The results showed that the discharge characteristics presented in the technical documentation for the NCR-18650b lithium-ion battery differ from the characteristics obtained as a result of a physical experiment on a real sample and the characteristics described in the standard mathematical model of the battery in Matlab. A comparative analysis of the relative error in the simulation of discharge processes in three intervals of the discharge characteristic is presented. Recommendations on improving the accuracy of modeling are given.