车用锂离子动力电池电化学模型修正方法

Aim to improve the accuracy of P2D model under the condition of high discharge rate, a modified method based on the average electrode model is proposed. The effects of sensitivity parameters-solid phase diffusion coefficient and particle size on the average electrode model are analyzed. Based on the Ratio of Potentio-charge capacity to Galvano-charge capacity(RPG), the coupling relationship between current and solid phase diffusion coefficient is established. The particle size distribution characteristics of electrode particles of li-ion power battery are obtained by charging and discharging tests and concluded as the weight coefficients according to the maximum particle size, medium particle size and minimum particle size. Then, a three-particle electrochemical model with variable solid phase diffusion coefficient is given. Meanwhile, the multi-power discharge test for single battery and the NEDC cycle test platform for battery pack are carried out. Compared with the traditional P2D electrochemical model, the accuracy of the proposed variable parameter model is increased by 80%, the error of average output voltage is no more than 0.02 V, and the maximum deviation is about 0.05 V. The experiment verifies the validity and accuracy of the variable parameter model, which provides theoretical support for the state estimation and control of the Li-ion power battery management system.