Comparison of the effect of linear and two-step fast charging protocols on degradation of lithium ion batteries

This work compares the effect of linear and two-step fast charging protocols on degradation of the Li-ion battery due to the solid electrolyte interphase (SEI) increase with the charging-discharging cycles based on an electrochemical and capacity fade coupled cell model. Since there is still a lack of knowledge regarding how the State of Charge (SOC) dependent charging profile affects battery degradation, different slopes of the linear charging profile and different combinations of the charging current level for the two-step charging protocol are chosen as sample protocols representing the profiles varying with the SOC. The simulation results indicate that the two-step increasing charging protocol can achieve the lowest capacity fade ratio over 3000 cycles; the linear decreasing charging protocol can achieve the lowest charging voltage increase. The capacity fade due to the SEI layer increase in the negative electrode results in a shift of the stoichiometry coefficient cycling range and therefore a lower cell equilibrium potential and power performance. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study compares the effects of linear and two-step fast charging protocols on the degradation of Li-ion batteries. The results show that the two-step increasing charging protocol achieves the lowest capacity fade ratio, while the linear decreasing charging protocol achieves the lowest increase in charging voltage.