Since 2005, the CEA has been developing a high-efficiency photovoltaic cell technology that breaks with the most widespread standard in the global industry. Silicon heterojunction (HJT) technology offers numerous competitive advantages, for reintroducing the industrial manufacture of solar modules in Europe. Further benefits arise from the relatively simple and economically attractive low-temperature heterojunction manufacturing concept, which requires fewer production steps and reduces energy consumption. The high cell efficiency and lower temperature coefficient also contribute to the significantly increased electricity yield of HJT modules compared to modules with conventional silicon solar cells.
In comparable conditions to those of industrial production, the CEA's teams manufactured 5-busbar cells on industrial HJT equipment supplied by Meyer Burger (at a rate of 2400 cells per hour). The efficiency was certified by German laboratory CalTeC-ISFH to be 23.9% over the whole surface of a standard size cell (244 cm²).
These results are in line with a road map predicting that efficiencies of 25% will be achieved industrially in the next 3 to 5 years; the efficiency of cells being made currently at solar photovoltaic panel factories is around 19%.
Photo: View of the pilot line for the manufacture of heterojunction photovoltaic cells at the French National Institute of Solar Energy/CEA Liten © P. Avavian
Record power of 348 watts
The CEA's teams also achieved a record rated module power of 348 watts using 120 heterojunction half-cells. This value was measured under the standard conditions of (IEC 60904). By comparison, the best high quality modules using 60 cells available on the market offer a power of around 320 watts with PERC (Passivated Emitter and Rear Contacted cell) technology in the same configuration.
This record was achieved using cells with an average conversion efficiency of 23.25%, with optimised metallization and interconnection using the SmartWire Connection Technology (SWCT™) process. The cells were developed and manufactured on the CEA's industrial pilot line. The module was then assembled in close collaboration with Meyer Burger.