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CEA is actively involved in several key work-packages of the IBC4EU project, addressing various innovative approaches that aim to improve the performance, reliability and/or sustainability of the developed IBC cells and modules.

For instance, Interdigitated back contact (IBC) solar cell architectures feature an interdigitated p / n pattern on the rear side. While very high-quality wafers are required to achieve the highest efficiencies, this need is even more critical for IBC cell concepts, where minority carriers must diffuse all across the entire wafer thickness to be effectively collected at the back. In collaboration with project partners, CEA contributes its expertise in ingot and wafer manufacturing to improve and better understand the wafer specifications (carrier lifetime, resistivity) required  by cell manufacturers for both N & P polarities, ultimately enhancing device performance. At the same time, with the increasing use of new cut-cell formats integrated into final module configuration, there is an observed increase in the impact of wafer edge recombination. New solutions are required to recover performance losses related to cutting and the newly non-passivated edge.

CEA has worked in WP2 and WP3 on innovative cut-edge repassivation solutions, based on customized Aluminum Oxide layers deposited over existing active layers. CEA has also developed a new 45° rotated wafer configuration, achieved by simply rotating the ingot during the squaring step. This modification aligns the preferential  mechanical cleavage plan within the silicon bulk with the cell’s metal pattern, allowing for a straightforward, laser-free wafer cut. This approach minimizes cut loss and results in extremely smooth and uniform edge morphology, making it highly compatible with the targeted edge passivation process. The effectiveness of these processes has been demonstrated at INES and successfully evaluated on integration lines of various project partners, including ISFH, Kalyon PV and ISCK.

Another significant concern for industrial partners is insuring the lowest possible environmental impact and carbon footprint of the proposed products. This challenge is adressed in the project by reducing the use of critical materials such as silver, and by focusing on the selection of materials at the module level (Bill of Material - BOM) to enhance the final module´s sustainability and reliability. To achieve the project´s objectives, CEA has evaluated different module configurations, integrating newly available materials with innovative interconnection techniques developed within the project. Understanding the interactions between polymer materials in the modules and the cells is essential, and the reliability of the final panel insured through accelerated testing. Based on these results, INES is able to propose alternative designs and materials that reduce the Global Warming Potential (GWP) of IBC4EU products, including eco-design in module packaging and reducing damage during transport and installation. For example, the usage of wooden module frames has been proposed as a replacement for traditional aluminum frames.

Finally, enhancing the operational reliability of production lines is a critical challenge for industrialization. This can be achieved through the development of predictive maintenance tools and software capable of providing real-time feedback on potential issues or defects on the production line. CEA is primarily working on an automated PL program analyzes all produced all wafer/cells at high speed, identifying and classifying defects observed during measurements. This enables the rapid identification and anticipation of potential issues on the production line, minimizing their impact on uptime or product performance.


CEA believes that the innovations introduced within the framework of the IBC4EU project will significantly enhance the competitiveness of the IBC products developed by the various partners. These advancements provide a solid foundation for achieving the project`s ultimate goal of establishing a strong base for European solar cell manufacturing.