An Analytical Model of Lithium-ion Battery Voltage Dynamics

The development of an analytical mathematical model of the lithium-ion battery voltage dynamics is considered. The proposed model differs from the well-known Shepherd model by taking into account the electrode polarization processes at various degrees of battery discharge, as well as taking into account the potential differences of electrode double layers, which helps improve its accuracy and adequacy. That is, the model takes into consideration the initial charge of the double layers and the membrane initial polarization, which differ from their equilibrium values. The proposed model is obtained by numerically and analytically converting the equations describing the dynamics of processes in lithium-ion batteries obtained by the method of mathematically prototyping energy processes proposed earlier by the authors. This method is essentially a unified approach to constructing correct (i.e., not contradicting the laws of physics) models representing the dynamics of physical and chemical processes of various natures. However, the lithium–ion battery model proposed in this article is valid only for certain assumptions, namely, at room ambient temperature and for a constant current discharge mode from any initial electrolyte polarization state. The proposed model can be used as a basis for developing digital twins of lithium-ion batteries designed to diagnose and predict the condition of lithium-ion batteries operating under normal climatic conditions in a constant current discharge mode.