CIGS recycling cuts solar cell production costs
Midsummer, with the support of Professor Christian Ekberg and PhD student Anna Gustafsson at the Chalmers University of Technology, has developed a process to recycle the CIGS residue accumulated when manufacturing thin film solar cells.
The recycling involves the use of oxygen in eliminating selenium, making it easier to process the remaining copper, indium and gallium.
Oxygen is permitted to flow over the CIGS, only after it has been pulverised, according to Gustafsson. "The method allows SeO2 to be formed and all the selenium is separated from the metals. The separated selenium can then be reformed at very high purity (over 5N purity, 99.999 per cent) so it can easily be reused in the solar cell production process without further purification".
Midsummer has already developed a high-efficient process for cadmium-free CIGS on stainless steel with sputtering. By using sputtering in all processing steps, the process cycles in the manufacturing of solar cells can be shortened. The solar cells can be made cadmium-free and also made on stainless steel substrates suitable for light weight flexible modules. This all contributes to a highly competitive method to manufacture thin film CIGS cells with high efficiencies. The process is a completely dry process and also an all-vacuum process, with less stringent requirements for clean-rooms etc.
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