Analyzing the impact of discharge rate on the cycle life of cylindrical lithium-ion batteries during fast charging

Abstract

In studies of lithium-ion battery performance and safety, dendrite formation has been considered a significant issue. Lithium dendrites can cause dangerous states, leading to internal shorts, thermal runaway, or explosions during the battery cycling process. Although researchers have focused on the charging rate in relation to this phenomenon, this study highlights the effect of discharge rate differences during fast charging on the morphology of lithium dendrites and cell cycle life. Remarkably, the study reveals that setting the discharge rate above 0.5C during high-rate charging serves as a mitigating factor against dendrite growth. Conversely, when the discharge rate falls below 0.5C, an increase in cell localized pressure and temperature is observed, promoting the growth of dendrites in a needle-like morphology. This phenomenon not only results from temperature differences linked to discharge rates but also arises due to spatial heterogeneity in the pressure experienced by the electrodes, influenced by the structural characteristics of cylindrical cells. We comprehensively analyze the effects of discharge rates on cell temperature and pressure distribution and propose a range of discharge rates that moderate dendrite growth. This novel perspective contributes to the overall stability of lithium-ion batteries, presenting a potential breakthrough in the ongoing efforts to address dendrite-related challenges.