A lithium-ion battery is a rechargeable secondary battery and is used in various industries such as computers, mobile phones, medical devices and electric vehicles. The main focus of a lithium-ion battery is a high energy density, high power and a long life cycle. But the degradation of capacity in a battery electrode brings great restrictions on the development of high-performance electrode materials. Electrode particles contract and expand during charging and discharging of a battery and mechanical breakdown occurring in this process is a major cause of degradation of the capacity of a lithium-ion battery. Factors that cause mechanical degradation include separator degradation, current collector degradation and active particle degradation. Among them, lithium ions entering and exiting the electrode particles is the main cause of degradation of the active particles. The battery is repeatedly charged and discharged, lithium ions enter and exit each electrode. In this process, the electrode particles are repeatedly contracted and expanded. As a result, the electrode particles are mechanically destroyed. In addition, this study intends to investigate the effect of external pressure on the development of electrode particle stress. For the purpose, an electrochemical-mechanical coupled 3D simulation model is developed and applied the external pressure of 0, 30, 50, 100MPa. A battery is discharged and charged at various discharge rate(1C, 2C, 5C, 10C), so that stress development of electrode particle is examined.
In this study, it is hard to find any particular characteristics in the battery charging process, but it was verified that, depending on the battery discharge rate condition, an external pressure may have a non-generative effect on the development of electrode particle stress.