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Title:
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Monolithic series interconnection for thin-film silicon solar cells on steel foil
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Author(s):
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Published by:
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Publication date:
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ECN
Solar Energy
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4-2-2008
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ECN report number:
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Document type:
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ECN-M--08-017
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Conference Paper
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Number of pages:
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Full text:
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4
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Download PDF
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Presented at: 23rd European Photovoltaic Solar Energy Conference and Exhibition, Valencia, Spain, 1-5 september 2008.
Abstract:
Roll-to-roll production facilitates flexible PV modules and a significant decrease of production costs for thin-film silicon solar cells. However, no standard processes for monolithic series interconnection on foil substrates are readily available. ECN is currently developing the technology and setting up a pilot line for the production of single junction and tandem solar cells based on microcrystalline and amorphous silicon on steel foil substrates. To allow monolithic series interconnection on these electrically conducting substrates, an insulating layer is required. In the presented module concept, first all layers of the solar cell are deposited, and after that series interconnection is realized by three depth selective laser scribes which are filled by insulating and electrically conductive inks.
In this paper, we present the current status of development for all key technologies required for the presented module concept: comprising a pinhole free insulating layer, an embossing process for this layer to apply light trapping textures on sub-micrometer scale, depth selective laser scribing by solid state YAG lasers, and screen printing pastes and processes for insulating and conductive inks curable at low temperature. First test samples have demonstrated the feasibility of the depth selective laser scribing and electrical series interconnection with the developed screen printing processes. Interconnection losses below 10% with respect to individual cells are anticipated when combining the presented processes for actual fabrication of monolithically interconnected thin-film silicon solar cells on steel foil.
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