Performance and durability of electrically conductive tape for shingled Si heterojunction technology cells
- National Renewable Energy Laboratory (NREL), Golden, CO (United States)
- 3M, St. Paul, MN (United States)
We report electrically conductive tape (ECT) was characterized and used to assemble shingled cell strings at low temperature to achieve high reliability Pb- and Ag-free interconnections. The volume resistivity for two considered ECTs are 0.13 ± 0.06 mΩ·cm and 0.47 ± 0.20 mΩ·cm and specific contact resistances, 6.85± 2.00 mΩ·cm2 and 6.30 ± 0.37 mΩ·cm2 using the emerging IEC 62788-8-1 Technical Specification for assessment of electrically conductive adhesives (ECA). Durability and performance of the technology in glass–glass mini modules were evaluated with temperature cycling, damp heat testing, and combined-accelerated stress testing (CAST). Through temperature cycling (-40°C to 85°C) applying five times the mini module short-circuit current in forward bias and in the multi climate CAST protocol, there was negligible degradation of fill factor after replacing connectors at the modules' cable leads; however, CAST resulted in short circuit current loss attributed to degradation in light collection by the cells, not the ECT. The IEC 61215-2 85°C, 85% relative humidity damp heat testing showed susceptibility of the HJT cells to effects of humidity in the electroluminescence intensity around the module perimeter that degraded power performance by 4% (relative). Contrasting the IEC 61215-2 qualification testing-based damp heat testing with CAST, factors such as the optical stress of CAST may precipitate the degradation of the modules whereas the humidity levels and duration of IEC 61215-2 damp heat testing may lead to excessive levels of humidity diffused into the modules, potentially resulting in degradation that is unrepresentative of the field.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
- Grant/Contract Number:
- AC36-08GO28308
- OSTI ID:
- 2228670
- Report Number(s):
- NREL/JA-5K00-86977; MainId:87752; UUID:b1f5962c-c9bc-4103-ac81-24cb39c3b159; MainAdminId:71204
- Journal Information:
- Progress in Photovoltaics, Journal Name: Progress in Photovoltaics Journal Issue: 1 Vol. 33; ISSN 1062-7995
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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