White Paper: Electroluminescence And Thermal Imaging Applications In The Photovoltaic Industry

By Nuno Pereira, Lógica E.M. - Photovoltaic Laboratory

Quality control is of the utmost importance for any high-tech industry. The complexity of the processes that we are dealing with — the considerable amount of variables that are to be monitorized and controlled — are good reasons to keep the production process under very tight control. The photovoltaic (PV) industry is a good example of this modus operandi. The globalization and worldwide competition doesn't leave room for improvisation. Excellency is the key word, and nothing below will survive in the next years.

Turnkey solutions are now available for any investor that wants to get into the PV business, but, at the end of the day, what really makes the difference "is not the car you drive but how you drive it." With present-day production line technology, it is quite simple to get from silicon (Si) wafer to assembled module in a very short time cycle, but what happens in between is what really matters. Several pitfalls occur in these production lines. Let's consider the cell as our starting point and, for the sake of simplicity, ignore what's behind. The standard simplified module production workflow is something like this: cell sorting, string assembly/ribbon soldering, lamination/encapsulation, and framing. Each stage can be responsible for adding some irregularities, such as cell mismatch, soldering defects, humidity insulation problems, and electrical insulation problems. The goal is to identify the defects prior to installation or, should that be the case, remove the module from a plant to avoid loss of energy production.