ULTRA-LARGE 20 × 20 CM~2 MC-SI SOLAR CELLS: IMPROVED CELL PROCESS RESULTING IN EFFICIENCIES EXCEEDING 15

摘要

Wafer size enlargement seems to be an effective cost reduction strategy of solar cell production. Within the last 10 years wafer size in cell production increased from 10 × 10 cm~2 to 15.6 × 15.6 cm~2. The next step will be an enlargement of wafer sizes up to 8 inches. Some cell manufacturers already announced the production of me solar cells based on ultra-large scale (ULS) wafers. But firstly technological challenges like mechanical yield during wafer and cell manufacturing respectively and homogeneity over total wafer surface have to be mastered (diffusion, texturisation, SiN-deposition, screen-printing). To be compatible to inline production lines cell processing experiments on ULS wafers were carried out using spray-on technique as alternative emitter diffusion. In the latest experiment we included a texturisation step in the process sequence resulting in a solar cell efficiency of 15.1 %.