HOW THE SOLAR FOIL IS MADE
The solar foil is a thin-film photovoltaic cell that is made by depositing thin layers on a flexible substrate. In our case the absorber is made of Copper, Indium, Gallium, Selenide (CIGS).
Methods of fabrication involve vacuum processes including co-evaporation, magnetron sputtering and wet chemical deposition.
Sunplugged operates a full production pilotline for flexible CIGS solar cells. This pilotline consists of two roll-to-roll sputtering systems, a roll-to-roll crystallisation furnace and a full-fledged wet chemical station for etching and chemical bath deposition.
Sunplugged is able to process up to 300 mm wide endless foils as well as 300×600 mm rigid substrates in this production line.
For module production (cell interconnection and encapsulation) Sunplugged operates one short pulse laser scribing station, a high precision screen printer (up to +/-3 microns accuracy and 1,6 x 1,6 meter printing area) and a soldering station. For module encapsulation two laminators (batch type vacuum laminator and Roll-toRoll laminator) are installed.
The starting point of our solar cell is a polymeric foil. In order to prepare the substrate for the succeeding processing steps it needs to be thermally treated and cleaned.
Deposition of Rear Contact
This is really a tricky part: All four elements (Copper,Indium,Gallium and Selenium) are sputtered and coevaporated onto the web. The deposition sequence and recipes determine the quality of the compound semiconductor and hence the efficiency of the solar cell device. The process pushes the envelope of the involved materials especially of the substrate and the evaporation sources.
Chemical Bath Deposition