Lithium‐Ion Battery Electrochemical‐Thermal Model Using Various Materials as Cathode Material: A Simulation Study

Abstract In this paper, the electrochemical‐thermal characteristics are studied by using 2D (two‐dimensional) axisymmetric multi‐physics model coupled with a 1D (one‐dimension) model to study thermal safety of the 18650 lithium‐ion battery with various cathode materials. LiCoO 2 (LCO), LiFePO 4 (LFP), LiMn 2 O 4 (LMO), LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA) and LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NMC) materials have been modeled about their temperature change in different charge/discharge rates. Also, battery with identical cathode material under various charging and discharging ratio is studied about the temperature safety. The simulation results showed that the temperature roughly increases by 5 degrees with the ratio of each increment of 2C for an identical material. Under the 10C ratio, the highest temperature of LiFePO 4 and LiNi 0.8 Co 0.15 Al 0.05 O 2 is 63.6 o C and 63.8 o C respectively, which means they have the best thermal stability and thermal safety. Among the five positive electrode materials, the thermal stability of LiFePO 4 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , LiMn 2 O 4 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 and LiCoO 2 decreased successively. The influence of different materials and charge/discharge ratio on the thermal behavior of the battery was analyzed and discussed. The simulation results are similar to the prediction results, but it can get the visualized results in principle with the advantage of shorter time, which is instructive to vast researchers.