PV MODULE INSPECTION
– INSUFFICIENT RIBBON AREA OVERLAPPED WITH THE BUSBAR
– MULTICRACKS ON THE CELL EDGE
We previously shared quite a number of quality issues related to improper staff operation and equipment maintenance. This month, our inspectors on the field caught more of such cases.
– Insufficient Ribbon Area Overlapped with the Busbar
One of them is some non-conforming PV modules with insufficient ribbon area overlapped with the bus bar (STD: ≥ 50%, Actual=40%).
The reason behind this is that the welding belt was loosened during the maintenance of the welding machine, resulting in the cell connectors being too short by about 20 to 25%, and the area of ribbon overlapping with the busbar was insufficient. The production line staff did not follow their own procedures when the defect was discovered, due to the lack of training, insufficient knowledge about product standards, and lack of product quality awareness.
This situation adds to indicate how important it is to have third-party accredited quality inspectors onsite.
– Multi-cracks on the Cell Edge
Another one is a poor-quality batch with 9% of the modules presenting branching cracks at the edge of the cells. During the manufacturing step preceding the cells stringing process, an accumulation of crystallized flux on the bending press block, due to lack of equipment cleaning and maintenance, has led to unevenness of the cells interconnectors. During the process of lamination, the uneven wires were transferring additional stress to the edge of the cells, which caused the cracks observed during EL test.
Apart from improper operation during production, this month, our inspector also found that the operation staff in the factory warehouse miss-placed pallet numbers under the wrong pallet group ID number when preparing the sampling list. A simple data copy and paste mistake may sometimes have severe consequences if left unchecked.