Yingli Green Energy Holding Co. says it has produced the first interdigitated back contact (IBC) n-type solar cells based on 6-inch wafers at an industrial pilot line within just three months by adopting the new production process co-developed by Dutch research center ECN and equipment manufacturer Tempress.
The production process is based on Yingli’s commercialized PANDA process for the low-cost production of conventional n-type solar cells (n-PERT). The process was adapted for IBC-type cells using the screen printing technology for patterning and metallization. The production of IBC cells in Yingli’s industrial pilot line proves that the commercial production of efficient IBC cells is feasible on short term.
ECN is focusing its research on n-type silicon solar cells as these are potentially more efficient than p-type cells and are less sensitive to degradation and impurities. Additionally, the back contact design of solar cells offers several advantages. They exhibit a higher voltage and deliver a higher current, because of reduced losses via recombination and a larger surface on the sunny side.
By producing the cells at Yingli, the consortium has now tackled the complexity of producing such cells. The consortium aims to produce cells that have an efficiency of 22 percent by the end of 2017. The development and production of commercial modules is expected for 2018. Moreover, the inherent bifacial character of the IBC cells will also allow pursuing the route of truly bifacial module technology.
“This result shows once again the synergy of our long lasting and fruitful cooperation with Yingli and ECN, who did the majority of work to achieve this. For Tempress this is an important opportunity to adapt and develop equipment and process that can be used in the production process of these next generation cells. A partner like Yingli combined with ECN, puts us in a position where developments can go really fast, which I think is best demonstrated by achievements like this. We are very thankful to have such valuable partners.” commented Albert Hasper, general manager of Dutch Solar Equipment company Tempress.
The cooperation with Yingli is very important for this development, says ECN researcher Dr. Ilkay Cesar. “Yingli has the facilities to produce high-quality solar cells on a large scale at low cost. This greatly enhances our opportunities for research and development on the cell process and module integration in a new way for our program. We are happy to partner with Yingli to continue the development of commercial processes for n-type solar cells. The pilot line now provides IBC cells in sufficient quantities to enable efficient back-contact module development which will boost the Dutch and EU PV tool and material supplier industry. The ECN Industry Research Program (IRP) aims to bring our simplified IBC technology to 23% within 3 years. IRP partners can start pilot production in less than 3 months as already demonstrated by Yingli.”
“It is our honour to cooperate with ECN and Tempress in producing IBC cells and we appreciate their highly industrial focus, which will enhance the chances to bring this product to the market in the short term. This cooperation and the pilot production of IBC cells are consistent with our long-term commitments to making solar electricity affordable and accessible for all through continued technology innovation,” said Dr Dengyuan Song, Chief Technology Officer of Yingli.
— Solar Builder magazine