摘要
结合Stoney公式的多光臂应力测量方法能够有效检测出薄膜电极在充放电过程中的平均应力.然而,经典Stoney公式仅适用于低应力水平的情况.运用修正的Stoney公式考虑了硅电极材料力学性质的变化和基底曲率剧烈变化情况下电极薄膜中应力的演化规律.基于应力和扩散相互耦合的三维非线性有限元模型,验证了修正Stoney公式的准确性.进一步,讨论了曲率分叉出现的条件,确保使用修正的Stoney公式时避免出现曲率分叉行为.
The multi-beam optical stress sensor method combined with Stoney equation is an effective approach to measure in-situ average stress in thin film electrodes upon lithiation/delithiation.However,the classic Stoney formula is applicable only at low stress states.A modified Stoney formula for stress measurement in thin-film Si electrodes was applied to account for the combined effects of the Li concentration-dependent material properties and large substrate curvature change.The numerical results based on three-dimensional non-linear finite element model for the full coupling of large deformation and Li diffusion confirm the accuracy of the modified Stoney equation.Further,a critical condition for the curvature bifurcation was discussed,which should be avoid when using the modified Stoney equation.
作者
刘佩琳
陆宇阳
郑东昌
何陵辉
倪勇
Liu Peilin;Lu Yuyang;Zheng Dongchang;He Linghui;Ni Yong(CAS Key Laboratory of Mechanical Behavior and Design of Materials,Department of Modern Mechanics,University of Science and Technology of China,Hefei 230027,China)
基金
the National Natural Science Foundation of China(11672285)
the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB22040502)
China Postdoctoral Science Foundation(2018M642532)
the Fundamental Research Funds for the Central Universities(WK2090050046)
the Collaborative Innovation Center of Suzhou Nano Science and Technology
the Fundamental Research Funds for the Central Universities.
关键词
修正Stoney公式
有限元
分叉
应力
塑性
大变形
modified stoney formula
finite element analysis
bifurcation
stress
plasticity
large deformation
