Public release of optimization of metallization scheme for thin emitter wrap-through solar cells for higher efficiency, reduced precious metal costs, and reduced stress.

Technical Report · Fri Aug 01 04:00:00 EDT 2008

DOI:https://doi.org/10.2172/940520· OSTI ID:940520

Ruby, Douglas Scott; Murphy, Brian ^[1]; Meakin, David ^[1]; Dominguez, Jason ^[1]; Hacke, Peter ^[1]

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1. Advent Solar, Inc., Albuquerque, NM

Back-contact crystalline-silicon photovoltaic solar cells and modules offer a number of advantages, including the elimination of grid shadowing losses, reduced cost through use of thinner silicon substrates, simpler module assembly, and improved aesthetics. While the existing edge tab method for interconnecting and stringing edge-connected back contact cells is acceptably straightforward and reliable, there are further gains to be exploited when you have both contact polarities on one side of the cell. In this work, we produce 'busbarless' emitter wrap-through solar cells that use 41% of the gridline silver (Ag) metallization mass compared to the edge tab design. Further, series resistance power losses are reduced by extraction of current from more places on the cell rear, leading to a fill factor improvement of about 6% (relative) on the module level. Series resistance and current-generation losses associated with large rear bondpads and busbars are eliminated. Use of thin silicon (Si) wafers is enabled because of the reduced Ag metallization mass and by interconnection with conductive adhesives leading to reduced bow. The busbarless cell design interconnected with conductive adhesives passes typical International Electrotechnical Commission damp heat and thermal cycling test.

• Research Organization: Sandia National Laboratories
• Sponsoring Organization: USDOE
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 940520
• Report Number(s): SAND2008-5411
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
ADHESIVES
AESTHETICS
DESIGN
EFFICIENCY
FILL FACTORS
INTERNATIONAL ELECTROTECHNICAL COMMISSION
OPTIMIZATION
POWER LOSSES
SILICON
SILVER
SOLAR CELLS
SUBSTRATES
Silicon-Surfaces.
Solar cells-Design and construction.
THERMAL CYCLING