An online temperature estimation for cylindrical lithium-ion batteries based on simplified distribution electrical-thermal model

Accurate modeling of electrical-thermal properties is essential for safe use and efficient and reliable thermal management of Lithium-ion batteries. However, online estimation of the internal temperatures of the battery is very difficult due to the limitations of sensor testing methods. To address this issue, this paper proposes a simplified distributed electrical-thermal model of the cylindrical lithium-ion battery to realize the online temperature estimation. First, the cylindrical battery is divided into microcells according to its actual internal Archimedean spiral winding structure and established the electrical-thermal model for each microcell. Then, these microcells are then connected in parallel to form a multilayer electrical-thermal model to better capture the core and surface temperature evolution of the battery. Extensive experiments are conducted and illustrated that this method can estimate the core and surface temperature of the battery accurately under different current rates and dynamic test conditions at wider temperature ranges (from 0 °C to 55 °C). And the estimation maximum root mean square error is 0.9384 K. Moreover, a comparison with other models shows that this model can not only realize online internal and external temperature estimation but also have high accuracy. • A simplified distributed electrical-thermal model • Dividing microcells based on Archimedes spiral • An online temperature estimation method with high accuracy • Model verification at a wide temperature range and dynamic conditions