Paggi Marco, Berardone Irene, Infuso Andrea, Corrado Mauro
IMT Institute for Advanced Studies Lucca, Research unit MUSAM - Multi-scale Analysis of Materials, Piazza San Francesco 19, 55100 Lucca, Italy.
Politecnico di Torino, Department of Structural, Geotechnical and Building Engineering, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
Sci Rep. 2014 Mar 28;4:4506. doi: 10.1038/srep04506.
Cracking in Silicon solar cells is an important factor for the electrical power-loss of photovoltaic modules. Simple geometrical criteria identifying the amount of inactive cell areas depending on the position of cracks with respect to the main electric conductors have been proposed in the literature to predict worst case scenarios. Here we present an experimental study based on the electroluminescence (EL) technique showing that crack propagation in monocrystalline Silicon cells embedded in photovoltaic (PV) modules is a much more complex phenomenon. In spite of the very brittle nature of Silicon, due to the action of the encapsulating polymer and residual thermo-elastic stresses, cracked regions can recover the electric conductivity during mechanical unloading due to crack closure. During cyclic bending, fatigue degradation is reported. This pinpoints the importance of reducing cyclic stresses caused by vibrations due to transportation and use, in order to limit the effect of cracking in Silicon cells.
硅太阳能电池中的裂纹是光伏组件功率损耗的一个重要因素。文献中已提出简单的几何标准，根据裂纹相对于主电导体的位置来确定非活性电池区域的数量，以预测最坏情况。在此，我们基于电致发光（EL）技术进行了一项实验研究，结果表明，嵌入光伏（PV）组件中的单晶硅电池中的裂纹扩展是一个更为复杂的现象。尽管硅的性质非常脆，但由于封装聚合物的作用和残余热弹性应力，裂纹区域在机械卸载过程中因裂纹闭合而能够恢复电导率。在循环弯曲过程中，会出现疲劳降解。这突出了降低运输和使用过程中振动引起的循环应力的重要性，以限制硅电池中裂纹的影响。
