A Novel Method for Estimating State of Power of Lithium-Ion Batteries Considering Core Temperature

Abstract

Operation above acceptable limits in terms of current, voltage, and temperature can lead to lithium batteries overheating, increasing the risk of thermal runaway, which can also degrade battery materials more quickly, reducing overall lifespan. Estimating the state of power (SOP) of a battery is necessary for battery safety control and preventing operation above acceptable limits. However, the SOP is influenced by coupled multiple parameters including the state of charge, state of health, and core temperature, which make it challenging to estimate comprehensively. Based on the electro-thermal model, this study proposes a multi-parameter coupled method for comprehensively estimating the SOP considering the core temperature. This method provides a robust approach to accurately assessing the SOP across varying core temperatures, states of charge (SoC), and voltage levels. The combination of maximum likelihood estimation, adaptive genetic algorithms for parameter identification, and the unscented Kalman filter for state estimation was found to enhance the accuracy and robustness of battery models. The results show that the battery core temperature and terminal voltage are important and the main limitation on the SOP, respectively. This study lays a strong foundation for effective energy management and life extension of lithium batteries, particularly in high-temperature environments.

Keywords

• lithium-ion battery
• SOP estimation
• electro-thermal model
• core temperature
• parameter coupling
• high-temperature safety