Damaged modules, especially with cell cracks, can be observed quite often in photovoltaic‐installations. Little knowledge exists about long‐term stability of precracked modules at real operating conditions. Previous investigations and existing standards focus on the degradation of new, defect‐free modules. This work highlights a twofold approach for life‐time study of precracked modules: (1) outdoor exposure of 54 precracked modules for 1 year and (2) artificial stressing of 20 representative precracked modules with a novel load test setup simulating snow and wind loads. The outdoor exposure reveals that at moderate weather conditions, no changes were detectable, neither in electric performance nor in EL‐images. However, the accelerated static load tests with stepwise increasing pressures point out that above a certain threshold, cracks grow. Below this threshold, formerly unseen cracks become visible at the loaded stage. In addition, modules with a smaller number of damaged cells have a stronger tendency to degrade further than modules with an already large number of cracked cells. Remarkably, the power output measured with a solar simulator after a stress test up to 2500 Pa (describing conservative proof conditions for severe snow loads according IEC 61215) remains unchanged for almost all modules.

中文翻译：

---

野外和实验室条件下光伏组件中电池裂纹的演变

在光伏装置中，经常会观察到损坏的模块，尤其是带有电池裂缝的模块。对于预裂模块在实际操作条件下的长期稳定性知之甚少。以前的研究和现有标准都集中在新的，无缺陷模块的降级上。这项工作强调了对预裂模块进行终生研究的双重方法：（1）54个预裂模块在室外暴露1年，以及（2）通过模拟雪和风载荷的新型载荷测试装置对20个代表性预裂模块进行人工应力测试。室外暴露表明，在中等天气条件下，电性能和EL图像均未检测到变化。但是，在逐步增加压力的情况下进行的加速静载荷测试表明，超过一定阈值时，裂纹会扩展。低于此阈值，在加载阶段会看到以前看不见的裂纹。另外，与具有大量破裂单元的模块相比，具有较少损坏单元的模块具有更强的进一步降解的趋势。值得注意的是，在最高2500 Pa的压力测试后，使用太阳能模拟器测量的功率输出（根据IEC 61215规定了严峻的雪载荷的保守证明条件）对于几乎所有模块而言都保持不变。