화학공학소재연구정보센터
Journal of the Electrochemical Society, Vol.164, No.13, A3426-A3439, 2017
A Strain-Diffusion Coupled Electrochemical Model for Lithium-Ion Battery
The effect of diffusion-induced stress on battery response, degradation and cyclic life is well established. Analysis of this reciprocal effect, however, where the strain alters diffusivity, is limited to first principle calculations. The change in lattice parameters due to intercalation/deintercalation significantly affects the required activation energy by the lithium-ion to hop between neighboring vacant sites. This in turn modifies the lithium-ion diffusion kinetics, and affects the ion transport inside the electrode, hence affecting the stress buildup. In present work this intricate two-way coupling is analyzed in the context of battery response and degradation characteristics. Here, we present stress evolution analysis within electrode particle using a strain coupled diffusion kinetics electrochemical-thermal model. The model addresses stress evolution for two scenarios: no-strain (NS) and strain-hindered (SH) coupling. The results show that diffusion-induced stresses are greatly influenced by the strain-diffusion coupling and significantly affect the battery response. In addition, the effect of strain-diffusion coupling on cyclic capacity loss is also studied. Material with strong SH coupling has shown significant reduction in cyclic capacity loss. Insights of this study will help develop better understanding of stress generation inside electrodes, and to engineer electrode material properties to achieve improved battery performance and long cyclic life. (c) 2017 The Electrochemical Society. All rights reserved.