Parameter sensitivity analysis of an electrochemical-thermal model for energy-storage lithium-ion batteries

Abstract

The lithium-ion batteries used for energy storage have the characteristics of large volume, high capacity, and long cycle life. Understanding the influence of physical parameters on electric potential and temperature is of critical importance for the design and operation of battery management systems. Here we developed an electrochemical-thermal coupled model that is composed of lithium-ion battery Pseudo-2D (P2D) model and heat transfer equations. A sensitivity analysis is carried out to illuminate the influence of various electrochemical parameters on battery capacity, terminal voltage, temperature curve and other technical indicators for a LiFePO₄ battery with the capacity of 117Ah. The sensitivity matrices of the parameters under different C-rates and depth of discharge regions are organized, and a new five segments sensitivity analysis method is proposed in this study, which is helpful to reduce the sensitivity variance caused by the change of capacity during the discharging process. The parameters which have the greatest impact on battery capacity, voltage, and temperature are sorted out and illustrated. Furthermore, the influence rules of electrochemical parameters on the capacity and temperature-related technical indicators have also been summarized.