Energy Storage Science and Technology ›› 2022, Vol. 11 ›› Issue (12): 3965-3977.doi: 10.19799/j.cnki.2095-4239.2022.0411

• Energy Storage Test: Methods and Evaluation • Previous Articles     Next Articles

Three-dimensional electrochemical-thermal coupling model of a lithium-ion battery module

Xueqing WEI1(), Haipeng DENG1, Yu ZHOU1, Bingchuan WANG2()   

  1. 1.School of Mechanical and Electrical Engineering, Central South University
    2.School of Automation, Central South University, Changsha 410083, Hunan, China
  • Received:2022-07-21 Revised:2022-08-07 Online:2022-12-05 Published:2022-12-29
  • Contact: Bingchuan WANG E-mail:1134425622@qq.com;bingcwang@csu.edu.cn

Abstract:

Lithium-ion batteries have been widely used in new energy fields, including electric vehicles, among others. Therefore, to facilitate the designing of thermal management schemes for reducing the uneven temperature variation in battery modules and improving battery durability, this study develops a three-dimensional electrochemical-thermal model that can show the heat spatiotemporal production rate and the temperature distribution of battery cells. Besides, the model can predict the electrical characteristics of different parts of electrode pairs and the temperature distribution of battery cells. Specifically, the single-cell thermal model is extended to a thermal model of a battery module comprising three single cells connected in parallel to investigate temperature aggregation phenomenon reduction in the battery modules. The experimental results verify the validity of the proposed electrochemical-thermal model. Specifically, single-cell and three-cell parallel battery strings are placed in an insulation box with a constant temperature of 25 ℃ and discharged at a constant current rate to provide quantitative data on the electrical and thermal behavior. The current model prediction agrees well with the experimental data. The average absolute errors of the cell terminal voltage and temperature are less than 0.016 V and 0.36 ℃, respectively, under the constant discharge current conditions of 0.5 C, 1 C, 2 C, and 3 C. however, the average temperature error of each surface of the three-cell parallel batteries does not exceed 0.4 ℃ under constant discharge current conditions of 0.5 C, 0.75 C, 1 C, 1.25 C, and 1.5 C. Further analyses show that the current density in the cathode material is related to the discharge depth and electrochemical reaction area. In the early and middle stages of discharge, the electrochemical reaction area is mainly at the tab, where the current density is the highest. Conversely, the electrochemical reaction area is mainly at the bottom of the cathode material, where the current density at the bottom is greater than that at the tab in the later stages of discharge. The temperature of a three-cell parallel battery module is not a simple superposition of the temperatures of single cells. Additionally, the temperature of the middle cell is higher than that of the two cells at the sides. In the battery module, when boundary conditions are consistent, the temperature of the two side batteries becomes distributed symmetrically. Furthermore, a temperature aggregation effect caused by air non-circulation among the cells exists. Therefore, the temperature of intermediate cells can be reduced by reducing the gap between monoliths or adding materials with high thermal conductivity to them as heat transfer media.

Key words: electrochemical-thermal model, battery module, lithium-ion battery, thermal properties, experiment

CLC Number: