TOPCon shingle solar cells: Thermal laser separation and passivated edge technology

• Published in: Progress in photovoltaics 2023-07, Vol.31 (7), p.729-737
• Main Authors: Lohmüller, Elmar, Baliozian, Puzant, Gutmann, Leon, Kniffki, Leander, Richter, Armin, Wang, Lili, Dunbar, Ricky, Lepert, Arnaud, Huyeng, Jonas D., Preu, Ralf
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Atomic layer epitaxy; edge passivation; Efficiency; Emitters; Energy conversion efficiency; Lasers; Metallizing; passivated edge technology; Photovoltaic cells; Separation; shingle solar cells; Solar cells; surface passivation; thermal laser separation; TOPCon
• ISSN: 1062-7995; 1099-159X
• DOI: 10.1002/pip.3680

This work shows the first demonstration of thermal laser separation (TLS) and post‐metallization passivated edge technology (PET) applied to tunnel‐oxide passivated contact (TOPCon) shingle solar cells. The shingle solar cells with 26.46 mm × 158.75 mm size are separated from industrial full‐square TOPCon host solar cells. The singulation is performed either by TLS from the front side (emitter side) or by conventional laser scribe and mechanical cleaving (LSMC) from the rear side (emitter‐free side). The TLS optimized in this work yields up to 0.2%abs more efficient shingle cells after separation in comparison with LSMC‐separated shingle cells. The most promising PET sequence identified for the singulated TOPCon cells consists of depositing an 8‐nm‐thin aluminum oxide layer by thermal atomic layer deposition at a temperature below 200°C in conjunction with subsequent hotplate annealing at 250°C. Application of the PET yields a boost of up to 0.5%abs in energy conversion efficiency for edge‐passivated TOPCon shingle cells in comparison with their performance directly after separation. This efficiency‐increasing impact of the PET sequence is found not to be strongly dependent on the separation process applied. The most efficient TOPCon shingle cell after PET achieves an efficiency of 22.0% and has been singulated by TLS. This work demonstrates thermal laser separation (TLS) and post‐metallization passivated edge technology (PET) applied to tunnel‐oxide passivated contact (TOPCon) shingle solar cells. The PET boosts the efficiency by up to 0.5%abs for edge‐passivated TOPCon shingle cells compared with their performance directly after separation. The most efficient TOPCon shingle cell after TLS and PET achieves an efficiency of 22.0%.