Thermal and solid electrolyte interphase characterization of lithium-ion battery

Thermal behavior and solid electrolyte interphase (SEI) are crucial topics for the development and operation of the lithium-ion battery. To investigate the thermal behavior and SEI formation in a lithium-ion battery (C-LiMn_0.5Ni_0.3Co_0.2O₂), a numerical method combining the pseudo-two-dimensional electrochemical model, heat transfer model, and capacity fading model is developed. For the battery operated at a low C-rate, the ohmic heat and the reversible heat dominate the heat generation at a low state of charge (SOC) and high SOC, respectively. Alternatively, the ohmic heat is the dominant factor causing heat generation at a high C-rate. The reversible heat reaches a maximum at the SOC of 65% due to the entropic coefficient of the cathode active materials. The SEI thickness increases around 70 nm with increasing the C rate cycling. The heat generation is the bottleneck for the resistance of Li⁺ ion conductivity at the SCI. The heat generation of the cathode is larger than that of the anode, which is caused by the low solid phase conductivity of the cathode. This analysis has provided useful insights into the thermal management of lithium-ion battery in the course of charging and discharging which is conducive to the development and safe operation of the battery.