锂离子电池电化学-热-力耦合数值模拟及分析

Numerical Simulation and Analysis of Electrochemical-Thermal-Mechanical Coupling for Lithium Ion Battery

建立了锂离子电池电化学-热-力耦合模型,并使用COMSOL Multiphysics软件进行了数值求解。研究了电化学-热-力耦合模型与电化学-力耦合模型的差异,对比了温度场以及电极粒子内部浓度场的变化,同时分析了隔膜孔隙度变化时外载对电池电压及容量的影响。研究发现:引入温度场后电池容量和电压平台会有所升高,模型温度会变低,粒子内部浓度相比电化学-力耦合更加均匀;当加入外载后,会导致电池电压和容量的降低,且同等外载对低放电速率下电池性能的影响更明显。此外还发现了电池在外载作用下会引起隔膜孔隙度变化进而影响电池放电性能。

The electrochemical-thermal-mechanical coupling model of lithium ion battery is established,and the numerical simulation is carried out using COMSOL Multiphysics.The difference between the electrochemical-thermal-mechanical coupling model and the electrochemical-mechanical coupling model is studied,the temperature and the change of the concentration of the electrode particles are compared,and the influence of the external load on the battery voltage and capacity when the porosity of the separator changes is analyzed.It was found that after the introduction of the temperature field,the battery capacity and voltage platform will increase,the model temperature will become lower,and the internal concentration of particles will be more uniform than electrochemical-mechanical coupling.Adding an external load will result in a decrease in battery voltage and capacity,and the same external load has a more obvious impact on battery performance at low discharge rates.In addition,it has been found that the battery will cause the porosity of the separator to change under the action of external load,which will affect the discharge performance of the battery.