Module Technologies for Tandem Photovoltaics

Schindelstringer im Module-TEC.
© Fraunhofer ISE / Foto: Dirk Mahler
Shingle stringer in the Module-TEC.

There are special requirements when joining the temperature-sensitive and thermomechanically demanding layers of silicon heterojunction and tandem solar cells. Traditional processes must be optimized and suitable materials used to ensure reliable bonding and module integration. 

We develop low-temperature-based solutions for connecting silicon heterojunction or tandem solar cells using conductive bonding, smart wire connection (SWCT™) and soldering processes based on low-temperature solders. Our research focuses on low costs, mechanical stability and electrical performance.

Although the temperature requirements during lamination are not as high as for interconnection due to the lower process temperature, tandem solar cells still have to be laminated at particularly low temperatures. We develop special gentle yet fast processes and material combinations for this purpose. For moisture-sensitive (tandem) solar cells, we adapt the bill-of-materials (BOM) and develop and optimize edge sealing concepts.

Due to the special requirements of silicon heterojunction (SHJ) and tandem solar cells, we pay particular attention to a comprehensive characterization of the connection points as well as the solar cells themselves. Various methods are available for this purpose, which are described in detail in the area of junction analysis. In particular, we investigate the interaction of the interconnection processes with the sensitive microstructure of the layers. The influence of subsequent processes during module integration (lamination) and long-term stability are addressed in order to identify possible weak points.

R&D-Services

Our R&D-Services on the Topic "Module Technologies for Tandem Photovoltaics" Include:

  • In-house test days to evaluate materials and processes
  • Production and shipping of strings in various configurations with their solar cells
  • Development of cost-effective and reliable material and process combinations (BOM development)
  • Production and testing of prototype modules and small series
  • Consulting and analysis of the compatibility of materials and processes with silicon heterojunction technology 
  • Detailed characterization of materials using thermal, chemical, microscopic and mechanical methods
  • Module material optimization for tandem solar cells
  • Development of edge sealing concepts
  • Layout optimization for tandem solar cells
  • We process with our stringers:

  • Conductive bonding (Full and half cells up to 161.7 mm × 161.7 mm; Up to 1600 cells per hour (throughput); Conductive adhesives in the temperature range 80-180°C )
  • Smart-wire-connection(SWCT™) (Half cells in M10 format; String length, string spacing and process parameters can be flexibly adjusted)
  • Soldering process based on low-temperature soldering (Full and half cells up to 210 mm x 210 mm; Round wire and flat wire connections with various low-temperature solders)
  • Half cells M6, M10, M12
  • Up to 1600 cells per hour (throughput)
  • Conductive adhesives in the temperature range 80-180°C
  • Various solder alloys (standard, lead-free, low-temperature)

More Information on this Research Topic

 

Photovoltaik Modules

Module-TEC

Production and process technology and extensive analysis options for module technology

 

MoQa

PV Modules Made From Perovskite Silicon Tandem Solar Cells Based on Q.ANTUM Technology

 

GreenSolarModules

Strengthening the German PV Industry for Effective Implementation of the Ecodesign Regulation and the EU Energy Label

Publications on this Research Topic

Publication

Influence of
Soldering Profile on Industrial Silicon
Heterojunction Solar Cells

Publication

Shingling Meets Perovskite-Silicon
Heterojunction
Tandem Solar Cells

Publication

Low-Temperature
Metallization and Interconnection

for Silicon Heterojunction and Perovskite Silicon Tandem Solar Cells

Kontakt

Achim Kraft

Contact Press / Media

Dr. Achim Kraft

Cell Interconnection

Fraunhofer ISE
Heidenhofstr. 2
79110 Freiburg

Phone +49 761 4588-5544

Torsten Rößler

Contact Press / Media

Dr. Torsten Rößler

Conductive Bonding

Fraunhofer ISE
Heidenhofstr. 2
79110 Freiburg

Phone +49 761 4588-5023

Benjamin Grübel

Contact Press / Media

Dr.-Ing. Benjamin Grübel

Soldering

Fraunhofer ISE
Heidenhofstr. 2
79110 Freiburg

Phone +49 761 4588-2580

Christine Wellens

Contact Press / Media

Dr. Christine Wellens

Encapsulation

Fraunhofer ISE
Heidenhofstr. 2
79110 Freiburg

Phone +49 761 4588-5856