An Electric Circuit Model for a Lithium-Ion Battery Cell based on Automotive Drive Cycles Measurements

The on-board energy storage system plays a key role in electric vehicles since it directly affects performance and especially autonomy. Highly restrained technology, the lithium-ion battery offers satisfactory characteristics in order to make electric vehicles competitive with conventional ones. In this article, the effort was focused on modeling and estimating parameters of the lithium-ion battery cell when used in an electric vehicle. First, a state of the art on different modeling methods has been presented. For this work the equivalent electrical circuit modeling has been chosen due to its accuracy, its simplicity, and its low speed of calculation. Secondly the second-order Thevenin model is introduced with the adopted method for identification using two different algorithms: Trust-Region-Reflective and Levenberg-Marquardt. And to take into account the dynamic behavior of the battery cell in an electric vehicle, the identification of the parameters of the model based on measurements data during driving cycles is presented. And finally, the model is validated by comparing simulation results to measurements using Mean Square Error (MSE) criteria.