摘要
本文针对光伏电池中多晶硅片的断裂问题,研究了晶粒取向对裂纹扩展的影响规律。通过设计一种对脆性多晶硅片间接拉伸的组合试样,进行裂纹扩展的原位拉伸试验。试验发现裂纹在不同取向晶粒内部扩展方向受晶粒取向的影响.表现为在跨晶界处方向发生偏转。为研究晶粒取向和裂纹扩展偏转的关系.首先,通过拉伸试验获得了不同取向差下裂纹起裂及扩展的细观规律;其次,通过晶体物理学中的光图像法测得了多晶体中各晶粒在观测平面内的取向差;第三,在ABAQUS中建立多晶硅片试样模型,用不同方向弹模的差异表征晶粒的各向异性性质。利用扩展有限元模拟晶粒中的裂纹扩展.发现裂纹模拟结果与试验结果较为一致。研究结果表明,晶界两侧的晶粒取向差与穿过该晶界的裂纹方向的偏转程度存在特定关系,基于此,在多晶硅体的裂纹扩展研究中,可以利用晶粒取向的特征预测其中裂纹的扩展特征。
The effect of grain orientation on the crack propagation of polysilicon in photovoltaic cells is studied in this work. The in-situ tensile test of crack growth is carried out by designing a combined sample which indirectly stretches the brittle polysilicon. It is found that the direction of crack propagation in different orientation grains is affected by the grain orientation, and the crack deflects at the grain boundary. Moreover, the relationship between the grain orientation and the crack propagation deflection is studied. Firstly, the micro-laws of crack initiation and propagation under different orientation differences are obtained by the tensile test. Secondly, the orientation difference of grains in the observed plane is measured by the optical image method in crystal physics. Thirdly, a sample model of polysilicon wafer is established in the ABAQUS software, and the anisotropic properties of grains are characterized by the difference of elastic modulus in different directions. The crack propagation in grains is simulated by the XFEM software. It is found that the simulated results of crack are in good agreement with the experimental ones. The results show that there is a specific relationship between the grain orientation on both sides of the grain boundary and the deflection degree of the crack direction passing through the grain boundary. Based on this, the characteristics of grain orientation can be used to predict the crack growth characteristics of polysilicon.
作者
吴潇璞
张阳博
左宏
WU Xiaopu;ZHANG Yangbo;ZUO Hong(State Key Laboratory for Strength and Vibration of Mechanical Structures,Shaanxi Key Laboratory of Environment and Control for Flight Vehicle,School of Aerospace,Xi’an Jiaotong University,Xi'an 710049,Shaanxi,China)
出处
《实验力学》
CSCD
北大核心
2020年第5期820-828,共9页
Journal of Experimental Mechanics
基金
国家自然科学基金面上项目(11572235)资助。
关键词
多晶硅
裂纹扩展
原位试验
晶粒取向差
polysilicon
crack propagation
in-situ tests
grain orientation differences
