State of power estimation of lithium-ion batteries based on electrochemical-thermal coupling model and constant power condition

Currently, lithium-ion batteries are widely used in industries such as new energy vehicles and energy storage as a clean new energy source. Battery power is a key indicator for measuring whether the battery system meets the requirements for new energy vehicle acceleration and climbing, as well as ensuring the normal operation of electrical equipment. In this work, a state of power (SOP) estimation method was proposed based on a simplified electrochemical-thermal coupling model and constant power condition. Firstly, based on the existing electrochemical model, a three-dimensional thermal description was added for prismatic batteries to construct an electrochemical-thermal coupling model. Secondly, by employing a model-driven approach and using a growth search algorithm, external characteristics estimation of the battery under constant power conditions was achieved. Finally, using voltage and current as constraints, a power-current dual-cycle growth search algorithm was proposed to complete SOP estimation based on constant power condition. Through simulations and experiments, it can be observed that this estimation algorithm can achieve SOP estimation across the entire State of Charge (SOC) range for different forecast time.