Solar Modules with Advanced Silicon Heterojunction - Interdigitated Back Contact Cells – SMASH IBC2

The SMASH-IBC2 project aims at reducing the cost of PV electricity by developing innovative high efficiency solar cells and modules. Two different technologies currently dominate the PV market. The first one is based on crystalline silicon (c-Si) devices which historically lead the market due to its proven reliability and efficiency. Thin film technologies also show a great potential in terms of efficiency and cost reduction. In this project both technologies will be merged to obtain high efficiency solar cells on thin c-Si wafers with simplified processes. This may be achieved through an innovative solar cell design called IBC Si-HJ (Interdigitated Back Contact Silicon Hetero-Junction). IBC Si-HJ cells have a high efficiency potential (=25%) achievable on thin wafers (=100µm) with a low temperature fabrication process (=200°C). Moreover a simplified and aesthetic module interconnection (coplanar) can be developed with these structures. To obtain a cost effective structure we will study different processes from the thin film technology and try to transfer them for c-Si solar cells fabrication. We will focus on one hand on thin layers and contact formation (chemical and physical vapor deposition, electrodeposition, epitaxy). On the other hand, simplified cell fabrication steps (laser contacting, ablation and scribing) will be developed to achieve a low cost and industrial process. The main goal of the project is to validate a cost-effective method for fabricating high efficiency PV modules, using 24% efficient c-Si solar cells, based on thin (100 µm) and large area (150 cm2) silicon wafers. The metallisation of these devices will be ITO- (Indium Tin Oxide) and Ag-free to reduce the cell cost. This achievement will be based on well identified scientifical and technological issues linked with different tasks in the project. Thanks to the previous projects on the same topic (QC-Passi, SHARCC, TopShot), an important knowledge has been developed by the different partners. A precise and realistic roadmap has therefore been determined, as well as associated milestones.