ADVANCES IN THE DEVELOPMENT OF A NOVEL MODULE DESIGN BASED ON ELECTRICAL CONDUCTIVE ADHESIVE GLUE FOR CONTACTING HIGHLY EFFICIENT N-TYPE SOLAR CELLS WITH PVD AL BACK CONTACT

摘要

As to now no cost-effective approaches for the application of physical vapor deposition of an Aluminum (PVD-Al) layer onto a c-Si solar cell and subsequent module integration has been successfully developed at industrial production level. In the present study, n-type Si solar cells based on a promising industrial process for PVD-Al contacts were used to investigate its integration into the module and evaluate modules long-term stability. The interconnection technique based on electrical conductive adhesives (ECA) was mechanically evaluated by peeling tests and accelerated climatic indoor tests (TC200, DH1000). Peeling test results and cell to module (CTM) losses show that the ECA used is very well able to contact the PVD-Al back coming along with a contact resistance comparable to soldered contacts. No damages after lamination were detected by means of electroluminescence (EL). Preliminary results show losses in Pmpp lower than 1% in average after 1000 hrs of damp heat (DH) test. Contrary after 200 cycles of thermo-cycling (TC) Pmpp losses are in average higher than 5%. Even though no cracks and metallization damages were observed, galvanic corrosion between the ECA and the Al layer was detected after climatic testing which seems to be responsible for the higher losses. Corrosion was suppressed by the use of glass on front and rear side and POE as encapsulant, which provided a better water barrier against humidity.