Photovoltaic glass quality inspection

The as-received glass-glass PV modules did not show any visible deficiencies and were used as reference during the test series. After the initial tests, the glass defect PV modules were divided into two subgroups: repaired specimen and non-repaired specimen.

Testing of experimental glass repair technique for glass-glass PV modules. After damp-heat test repaired modules showed no signs of water ingress. Economic and ecological feasibility shown using Cost Priority Number metric. Solar photovoltaic (PV) energy is a crucial supply technology in the envisioned renewable energy system.

Especially critical are those defects that occur at the edges of the glass sheets – an area usually not covered by standard vision systems. Micro-cracks and chips of the solar glass panels are a major cause of glass breakage and their detection is important for assuring highest quality standards.

Common optical inspection systems for quality assurance and process control are mostly designed for unstructured glass. The surface struc-ture, as used e.g. for glass substrates of silicon solar modules, tends to create similar or even stronger optical signals in the vision system than the actual inspected defect.

Especially since glass defects arise more frequently at glass-glass PV modules [ 12, 13 ]. Glass defects can disrupt the insulation of the encapsulant layer and PV cells, which can lead to ingress of water. This affects the reliability of the PV modules and might cause safety and/or performance issues [ 11 ].

Glass defects impact the economic performance of a PV system in multiple ways. The most obvious effect is the potential (in)direct performance loss of PV modules, which results in reduced economic revenues. Secondly, PV modules that suffer from glass defects may no longer meet safety requirements, therefore these modules are replaced.