Temperature Estimation of Multiple Places for Lithium-Ion Batteries Based on Improved Electrochemical Thermal Modeling

Knowledge of temperature state of lithium-ion battery is essential to ensure its safe operation and mitigate the mileage anxiety of electric vehicle. For accurately acquiring the temperature state of lithium-ion batteries, this study develops a state of temperature (SOT) estimation framework, which accounts for multiple places temperature estimation and is concerned with wide variation range and whole battery lifespan. To this end, a simplified electrode-averaged model with temperature compensation is firstly established based on a pseudo-2-dimension (P2D) model to characterize the electrical characteristics, and a two-state lumped thermal model is leveraged to describe the heat transfer characteristics inside the battery. On this basis, an improved electrochemical-thermal model (IETM) is established. After that, the square root cubature Kalman filter (SRCKF) is integrated to achieve accurate temperature estimation of the pole ear and surface in the battery. The effectiveness and feasibility of the proposed multiple places temperature estimation method are verified under various conditions. The experimental results substantiate that the proposed method can accurately estimate the pole ear temperature and surface temperature with the maximum error of less than 1.10°C.