Thermal Monitoring and Multi-state Estimation of Li-ion Batteries Using a Control-oriented Integrated Electrothermal Framework

We propose an integrated design for the combined estimation of state-modified cell core temperature, temperature-corrected state of charge (SOC), and state of energy (SOE) of lithium-ion batteries (LIBs). First, a control-oriented integrated electrothermal coupled model is constructed. The observability of the proposed MIMO system is rigorously investigated, and an adaptive PI observer is formulated for the combined estimation task. Based on the proposed model, the electrical parameters are identified using improved experimental techniques, while the thermal model parameters are estimated online. Finally, the practicability of the proposed technique is verified using a test bench. The experimental results show the RMSE<0.5% for SOC and SOE estimation, and the RMSE<0.25°C for core temperature estimation. Moreover, the comparative results demonstrate high robustness against incorrect initial values, high-current dynamic loadfiles, and critical operating temperatures, which highlights the underscores of the proposed framework in improving the safety of LIBs in practical applications.