Parametrization and Core Temperature Estimation of Lithium-Ion Batteries for Thermal Management

The analysis of battery core temperature is critical for the battery management system (BMS) to protect the li-ion batteries from thermal runaway reactions which can lead the batteries to potential damage, but directly it is difficult to measure. This experimental study proposed a method to estimate the core temperature based on the two-state lumped thermal model using a Kalman filter. As an improvement, the effect of changes in entropy and overpotential on heat generation are analyzed. The constant current charge/discharge experiments are carried out using lithium-ion batteries to determine the parameters of the thermal model and to estimate the core temperature. For estimated results validation and model construction, temperatures are measured with thermocouples built inside and outside of the battery cells. The accuracy of the core and surface estimated results are validated with a mean absolute error of around 0.1 Celsius and 1.6 Celsius respectively.