The German research institute ISC Konstanz has claimed an energy conversion efficiency of 24.12% for a TOPCon back contact (TBC) solar cell. The researchers said their IBC4EU solar cell was designed in accordance with the polyZEBRA concept.
The result was confirmed by the German Institute for Solar Energy Research Hamelin (ISFH). “The certified efficiency of 24.12% appears to be higher than that achieved with internal measurements,” said ISC Konstanz researcher Jonathan Linke. pv magazine, referring to the uncertified result of 24.0% that the research group announced in December. “It is the highest ever achieved solar cell efficiency produced at ISC Konstanz.”
The cell also achieved an open circuit voltage of 709.5 mV, a short circuit density of 11,355 mA and a fill factor of 82.04%.
“Considering that laboratory cell manufacturing of standard industrial cells at ISC Konstanz is completely dependent on manual handling of wafers, machines used for numerous cell concepts, and that screen printing only takes place on a few tenths of the cells in a batch, this efficiency already as targeted,” Linke added. “An implementation of polyZEBRA technology in an automated production line is expected to result in cell efficiency of over 25% with lower operating costs compared to existing TBC cell concepts, with module efficiency ultimately exceeding 24%.”
The polyZEBRA cell manufacturing process uses a unique and inexpensive laser-based process to achieve passivating contacts at both polarities and is suitable for mass production, according to its makers.
“Currently, the ISC team is optimizing individual process steps to further increase the efficiencies demonstrated in the laboratory and implementing simplified process sequences to further reduce the expected costs of a future production line planned in 2025,” said Linke. “The cell development was funded by the European Union’s Horizon Europe research and innovation programme.”
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