AI SI LI (China) Test Equipment Co., Ltd. IEC 61215 MQT 10 UV Preconditioning Chamber,PV modules aging tester UV-Volume

One of the significant factor to snail trails is the composition of EVA. EVA with suitable substance could resist snail trails. Products of some EVA suppliers have been proved to work well. Backsheet is not the key contributor to snail trails. Snail trails will always appear with or without backsheet. Narrow cracks, or microcracks, are also a key factor. They prevent the moisture from evaporating out of the module, hence effectively preventing the humidity inside PV module from dropping. It is easier to create snail trails under such condition. Compared with regular Damp Heat test, UV+DH test condition plus specially designed evaluation samples could generate faster results. It is proven that it will shorten the testing time by 50%. Also, straight line cracks caused by laser cut is effective and helpful for quantitative evaluation of snail trails.With UV+DH test conditions, the probability of snail trail appearance is guaranteed.It can accelerate the process of PV module and EVA R&D. Most white belt zones, which were found along the straight cut lines, converted into snail trails.