Dr. Sylke Meyer
 

Senior Scientist 

Fraunhofer Center  for Silicon Photovoltaics CSP

 Education:

• PhD in Biochemistry, University Halle (Germany)

•Team leader for chemical analytics at Fraunhofer CSP 

  Since 2009 research  for PV

  Fundamental research: 

   - protein biochemistry /enzymology

   - Biotechnology

   - RNA biochemistry

Abstract:

The investigation of defects and degradation in photovoltaic (PV) modules has become an important subject, since reliability and product lifetime are key to system performance and to warranty conditions. One of the degradation effects that have been observed increasingly during recent years are “snail trails” thus called because of their visual appearance. They occur a certain period (several months to several years) after initial installation and appear as discolorations on the cell edges and as intersecting dark lines. Snail trails are a widespread phenomenon affecting modules from many manufacturers worldwide. These dark traces have been identified as discolored silver grid fingers along the cell edges or at cell cracks. We were able to show that silver nanoparticles accumulating within the encapsulation foil directly above the grid finger cause the brownish discoloration and that certain properties of the encapsulation and back-sheet foils trigger the formation of these nanoparticles. We suggest a reaction model explaining the formation of snail trails from a chemical point of view.Moreover, we present several lab test procedures which were developed to examine polymer foils for their discoloration sensitivity or resistivity.

The influence of the grid finger discoloration on module performance is discussed.