Simulation Study On M1254S2 Button-Type Lithium-Ion Batteries

The preparation technology of lithium-ion batteries with high stability,high energy density and long life is an important guarantee for the safe,stable,and sustainable operation of mobile smart devices.The above-mentioned performance requirements for batteries are increasing especially with the advent of the 5G era and the continuous advancement of highly integrated chip manufacturing technology.In this paper,a P2D-based electrochemical model was established.By using the COMSOL multi-physics field simulation software to investigate the relationship between the heat generation behavior during the battery cycle and its influence on the electrochemical performance.A Li Co O₂ battery with a capacity of 67.1 m Ah and battery type M1254S2 was used as the modeling object.The main research results are as follows.（1）The charge-discharge rate can cause different degrees of electrode polarization,resulting in temperature changes that affect the diffusion coefficient and reaction rate coefficient of each component.The charge/discharge conditions of 0.2C/0.5C/1C were simulated respectively,and the results show that the cell runs for a long cycle at 0.2C and the temperature is maintained at a stable level of about 298 K.The rate of capacity fade caused by them in 20 cycles is 0.73%,1.18%and 1.69%respectively.A one-dimensional electrochemical-three-dimensional thermal coupling model was developed to predict that the cell heat distribution is mainly concentrated in the central region.The heat transfer coefficients of the battery were simulated by varying the steel shell materials in the cycle under 1C operating conditions to 1 W（m² K）^-1,10W（m² K）^-1 and 20 W（m² K）^-1 respectively,and the results showed that the peak temperatures of the cell were 317.68 K,301.55 K and 299.95 K in order.The results show that materials with higher heat transfer coefficients can guarantee the stability of the cell temperature during running.（2）The mechanism of the influence of the initial concentration of electrolyte on the electrochemical performance of the cell during the long cycle of the cell was revealed,and the capacity decay rate was better at a concentration of 1000 mol m^-3 than that of 1200 and 1600 mol m^-3.The thickness of SEI film also increased with the increase of fading rate.