In consideration of the high-density dislocations from the lithiation process of high-capacity electrodes in Li-ion batteries, in this paper, a new elastoplastic model is established to describe the diffusion-induced ...In consideration of the high-density dislocations from the lithiation process of high-capacity electrodes in Li-ion batteries, in this paper, a new elastoplastic model is established to describe the diffusion-induced deformation and damage fracture. With the help of the relative physical quantities and state of charge, the surface damage and fracture behaviors of electrode materials are discussed based on the elastic-perfectly plastic(PP) and the strain gradient plasticity(SGP) theories, respectively. The results show that the lithiation deformation could be alleviated by reducing the electrode scale, and the plastic flow can play an essential role in the extrusion ratcheting effect relating to the upper surface fracture. Furthermore, the interface damage is more likely to appear by increasing the initial bond stiffness at the upper surface, which has little effect on the later fracture. A strong size effect is also found in the damage and fracture critical curves for the PP and SGP models.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 11872054 and 11972157)the Natural Science Foundation of Hunan Province (Grant No. 2020JJ2026)the Science and Technology Innovation Project of Hunan Province (Grant No. 2018RS3091)。
文摘In consideration of the high-density dislocations from the lithiation process of high-capacity electrodes in Li-ion batteries, in this paper, a new elastoplastic model is established to describe the diffusion-induced deformation and damage fracture. With the help of the relative physical quantities and state of charge, the surface damage and fracture behaviors of electrode materials are discussed based on the elastic-perfectly plastic(PP) and the strain gradient plasticity(SGP) theories, respectively. The results show that the lithiation deformation could be alleviated by reducing the electrode scale, and the plastic flow can play an essential role in the extrusion ratcheting effect relating to the upper surface fracture. Furthermore, the interface damage is more likely to appear by increasing the initial bond stiffness at the upper surface, which has little effect on the later fracture. A strong size effect is also found in the damage and fracture critical curves for the PP and SGP models.
