Static Electric Equivalent Circuit of Commercial Lithium-Ion Battery Cells Using Genetic Algorithms

In this work, a static electrical equivalent circuit (EEC) is proposed based on the charge and discharge performance of lithium-ion battery cells (LiBs), which can be obtained either directly from datasheet, or by a simple constant current charge/discharge cycle. The battery cell behavior is described by a non-linear mathematical representation with only dependency on the current rate (C-rate) and the state of charge (SoC) of the battery cells. Its coefficients are optimized using a single objective genetic algorithm and the methodology is tested on five different chemistries and various shaped commercial LiB cells. The results have shown a good agreement between the simulated and the experimental values. A simple and reasonably accurate EEC is proposed in this work, which can be part of the performance evaluation criterion of electric drive of the vehicles as well as investigating a potential energy storage system.