Multiscale thermo-mechanical fracture analysis of polycrystalline silicon shells in photovoltaic modules by a combined phasefield – continuum damage approach.

全球日益增长的能源需求、生态优势和经济效益是光伏组件应用的三大看点。占主导地位的光伏组件技术是基于多晶硅。构成光伏组件的多晶硅片（PSW）的脆性断裂显著降低了电效率。强大的PV模块的设计，因此，不可避免地需要一个彻底的调查PSWs中的损坏事件。本项目的目标是开发一个有效的和准确的模型的损坏引起的热或机械负载的PV模块，无论是在本地规模的PSW和全球规模的PV。为此目的，相场模型在局部尺度上和一个连续的全球尺度上的损伤方法的组合方法被说服。该项目的主要方面是：（i）发展了一种新的相场脆性断裂模型，该模型考虑了PSW中的各向异性，（ii）发展了一种计算程序，以研究PSW中由生产过程引起的残余应力（iii）基于几何非线性理论，建立了各向异性相场模型的连续壳单元，（iv）包括PSW和密封剂的PSW的结构元件的开发（v）通过实验分析验证纯机械模型（vi）在相场和连续损伤模型中实施热-机械耦合（vii）通过文献中的基准问题进行验证。这些步骤将在政府新闻处和行政管理处的密切合作下进行，各方针对手头问题的经验。

The increasing global energy demand, ecological advantages and the economical benefits are three major points for the application of photovoltaic(PV)-modules. The dominating PV-module technology is based on polycrystalline silicon. Brittle fracture of polycrystalline Siliconwafers (PSWs), making up the PV-module, significantly degrades the electrical efficiency. Design of robust PV-Modules, therefore, inevitably requires a thorough investigation of damage events in PSWs.The objective of the present project is the development of an efficient and accurate model of damage induced by thermal or mechanical loads on the PV-module, both at the local scale of the PSW and the global scale of the PV. For this purpose a combined approach consisting of phasefield models on the local scale and a continuum damage approach on the global scale are persued. Essential aspects of the project are: (i) development of a novel phase-field model for brittle fracture accounting for the anisotropy in PSWs, (ii) developing a computational procedure to investigate the residual stresses in PSWs initiated from the production processes (cofiring, flattening, and soldering), (iii) developing a continuum-shell-element for the anisotropic phase-field model based on the geometrically nonlinear theory, (iv) development of a structural element for a PSW comprising of the PSW and the encapsulant (v) validation of the purely mechanical model by experimental analysis (vi) implementation of the thermo-mechanical coupling in the phasefield and continuum damage models (vii) verification by benchmark problems from the literature.These steps will be conducted within a close collaboration between ISD and IAM based on the expertise and experience of each side for the problem at hand.