Accelerated ageing tests of photovoltaic laminates are requested by the IEC standards for quality control, which require the assessment of the electrical power losses after a prescribed amount of temperature and/or humidity cycles inside a climatic chamber (thermal cycling, humidity freeze, and damp heat tests). Since electric damage is measured only at the end of such tests, its kinetics induced by thermo-elastic stresses and the related degradation phenomena are reported in few cases. The aim of this study is to investigate the progress of damage, reporting the results of an unprecedented experimental campaign on a photovoltaic mini-module composed of nine multi-crystalline silicon solar cells, one of them containing a cracked cell, subject to a revised thermal cycling test including moisture. Every 40 cycles, and up to 460 (corresponding to 1840 h of testing), the progress of electric damage is assessed by monitoring the evolution of the overall electric resistance of the module. Moreover, electroluminescence images are taken with the same time interval, to assess local damage phenomena responsible for electric power-losses. Cracks are found to significantly accelerate the progress of damage as compared to what happens in intact solar cells, inducing progressive gridline failure and the spread of electrically inactive zones.

中文翻译：

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光伏组件加速老化损坏的无损监测

IEC 质量控制标准要求对光伏层压板进行加速老化测试，该标准要求评估在气候室（热循环、湿度冻结和湿热）内经过规定数量的温度和/或湿度循环后的电力损失测试）。由于仅在此类测试结束时才测量电损伤，因此在少数情况下报告了由热弹性应力引起的动力学和相关的降解现象。本研究的目的是调查损坏的进展，报告对由九个多晶硅太阳能电池组成的光伏微型模块进行的前所未有的实验活动的结果，其中一个包含破裂的电池，受修订的热包括水分在内的循环测试。每 40 个循环，直到 460 小时（对应于 1840 小时的测试），通过监测模块整体电阻的演变来评估电损坏的进展。此外，以相同的时间间隔拍摄电致发光图像，以评估导致电力损失的局部损坏现象。与完整太阳能电池中发生的情况相比，发现裂纹会显着加速损坏的进程，从而导致渐进式网格线故障和电非活性区域的扩展。