Large Plastic Deformation in High-Capacity Lithium-Ion Batteries Caused by Charge and Discharge
Large Plastic Deformation in High-Capacity Lithium-Ion Batteries Caused by Charge and Discharge
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DOI：
10.1111/j.1551-2916.2011.04432.x
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发表时间：
2011-06
影响因子：
3.9
通讯作者：
K. Zhao;M. Pharr;S. Cai;J. Vlassak;Z. Suo
中科院分区：
文献类型：
--
作者：
K. Zhao;M. Pharr;S. Cai;J. Vlassak;Z. Suo
最近有越来越多的证据表明，锂离子电池的大容量电极在充放电循环后可能无法恢复初始形状。这种塑性行为在这里是通过建立一个理论来研究的，该理论耦合了大量的锂离子作用和变形。在非平衡热力学中分析了应力作用下电极小元件中的均匀锂化和变形，允许讨论某些过程的平衡，而不是另一些过程的平衡。当应力达到屈服条件时，假定单元发生塑性变形。将该理论与扩散方程相结合，分析了恒速充放电电极的球形颗粒。当充电率较低时，锂在颗粒中的分布接近均匀，颗粒中的应力较低，没有发生塑性变形。当充电率较高时，锂在颗粒中的分布不均匀，颗粒中的应力较大，可能导致断裂和空化。
Evidence has accumulated recently that a high-capacity electrode of a lithium-ion battery may not recover its initial shape after a cycle of charge and discharge. Such a plastic behavior is studied here by formulating a theory that couples large amounts of lithiation and deformation. The homogeneous lithiation and deformation in a small element of an electrode under stresses is analyzed within nonequilibrium thermodynamics, permitting a discussion of equilibrium with respect to some processes, but not others. The element is assumed to undergo plastic deformation when the stresses reach a yield condition. The theory is combined with a diffusion equation to analyze a spherical particle of an electrode being charged and discharged at a constant rate. When the charging rate is low, the distribution of lithium in the particle is nearly homogeneous, the stress in the particle is low, and no plastic deformation occurs. When the charging rate is high, the distribution of lithium in the particle is inhomogeneous, and the stress in the particle is high, possibly leading to fracture and cavitation.