Ultrasonic Tinning of Al Pads for Silver- and Lead-Free Cell Interconnection
DOI:
https://doi.org/10.52825/siliconpv.v3i.2678Keywords:
Ultrasonic Tinning, Silver-Free, Cell InterconnectionAbstract
Polysilicon on oxide back junction solar cells offer a high efficiency potential with significantly reduced silver consumption by using an aluminum front grid. The cell interconnection typically requires additional silver pads for soldering. Ultrasonic tinning of aluminum generates silver-free tin solder pads which can further decrease the silver consumption. Here, we demonstrate ultrasonic tinning on front side Al pads of polysilicon on oxide back junction solar cells solar cells for a silver-free cell interconnection. We report low damage to the passivation layers with local losses in implied open circuit voltage of 5 mV to 15 mV. On cell level, this results in small open circuit voltage losses of 1 mV to 1.5 mV, or 0.2 %. Single cell mini module fabrication shows moderate cell-to-module losses of 1.3 % to 2 %, reaching up to 20.8 % module efficiency.
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Copyright (c) 2025 Malte Brinkmann, Henning Schulte-Huxel, Christina Hollemann, Byungsul Min, Sebastian Junge, Rolf Brendel
This work is licensed under a Creative Commons Attribution 4.0 International License.
Accepted 2025-12-18
Published 2026-01-20