Charging Optimization of Lithium-Ion Batteries Based on Charge Transfer Limitation and Mass Transport Limitation

Fast charging of lithium-ion batteries is essential to alleviate range anxiety and accelerate the commercialization of electric vehicles. However, high charging currents seriously deteriorate battery life due to the danger of metallic lithium deposition on the anode and the accompanying degradation reactions. In this work, a reduced-order electrochemical-thermal coupled model with typical side reactions is applied to capture the dependent variables related to the behavior of lithium plating. To completely suppress lithium plating, two novel charging algorithms are designed based on the constraints of the minimum lithium plating overpotential in the anode and the maximum surface concentration at the anode/separator interface, respectively. The definitions of the sensitive parameters in the two algorithms are weighed, and the current rates of 0 to 100% state of charge at different temperatures are optimized. Then, the fast charging strategies under the specific temperatures are optimized according to the sequence of preventing the minimum lithium plating overpotential, saturated surface concentration and cut-off voltage from exceeding the preset values. Finally, the proposed charging strategies and the conventional charging protocols are performed in cyclic aging tests at different temperatures, which verified that the proposed charging strategies can significantly shorten the charging time and delay battery aging.

Automated summary

Fast charging of lithium-ion batteries is crucial for electric vehicle commercialization and addressing range anxiety. However, high charging currents can lead to lithium deposition on the anode and degradation reactions, decreasing battery life. This study develops a simplified electrochemical-thermal model to capture the behavior of lithium plating and proposes two charging algorithms to suppress plating. The algorithms consider constraints on plating overpotential and surface concentration. The proposed strategies are experimentally validated to significantly reduce charging time and delay battery aging.