Guidelines for accurate current-voltage measurement of high-efficiency c-Si solar cells

摘要

The market for commercial crystalline silicon (c-Si) solar modules has been ruled for decades by the well-established ribbon-interconnected Al-BSF solar cells, making their metrology and in particular the current-voltage measurement well defined and reproducible. The recent appearance of high-efficiency technologies at mass production level, such as PERC, PERT, heterojunction or back-contacted, coupled to advanced module designs like multi-wire or shingle interconnection, sometimes in bifacial configuration has raised some metrological concerns. In most cases, no norms were in place, leaving manufacturers free to rate the power of their devices by a procedure of their choice. As the pricing of solar cells is based on their energy conversion efficiency in standard test conditions, such a situation is not suitable either for manufacturers or for customers. Indeed, without a well-defined framework for the measurement, the module manufacturer and of course, the final customer, might pay a wrong price. The present contribution aims at giving an overview of the new challenges that high-efficiency c-Si solar cells are facing when it comes to assessing their optical and electrical performances, as well as providing guidelines for their accurate measurement.