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Insights on Cell Edge Defects Impact and Post-Process Repassivation for Heterojunction
B. Portaluppi, S. Harrison, V. Giglia, A. Sekkat, D. Munoz-Rojas
Heterojunction, AlOx, Shingle, Cut Losses, Edge Repassivation
Silicon Materials and Cells
Subtopic: Low Temperature Route for Si Cells
Event: 37th European Photovoltaic Solar Energy Conference and Exhibition
Session: 2DV.3.16
504 - 507
ISBN: 3-936338-73-6
Paper DOI: 10.4229/EUPVSEC20202020-2DV.3.16
0,00 EUR
Document(s): paper


Shingle and half-cell integration are both very promising paths to boost power module without modification of heterojunction (SHJ) solar cell structure. However, significant efficiency losses are measured after the cell cut-step, linked to the newly unpassivated edge generated. Hence, photovoltaic industry has to face new challenges to fully benefit from these new designs and develop solutions to either reduce the impact of the cleavage or be able to recover the cut-losses thanks to dedicated post-process steps. Currently thermo-mechanical separation and laser scribing are the most common techniques used for the wafer splitting and both lead to similar final electrical losses at cell level, around -0.3% absolute efficiency degradation for example for half-cell. However, edge final morphology and defect nature remains very different with for instance a much smoother edge obtained for the thermos-mechanical process. In this work, we firstly intend to give guidelines to understand the impact of the edge defects on cell performance, and highlight the importance of controlling the extra-damages brought by the cut process on the final edge morphology quality. Indeed, repassivation process impact (necessary to recover the power losses), as shown in the second part of the study, can be strongly dependent of the chosen separation technique. Finally, different post-process repassivation approaches, adapted to SHJ technology specificities, will be presented along with first results obtained on SHJ cells.