Title:	Interconnection Technology for the Next Generation of (Temperature-Sensitive) Solar Cells such as Heterojunction and C-Si/Perovskite Tandem
Author(s):	Y. Zemen, S. Wendlandt, B. Litzenburger, L. Podlowski
Keywords:	Heterojunction, Module, Low Temperature, Metallization
Topic:	Photovoltaic Modules and BoS Components
Subtopic:	PV Module Design and Manufacturing
Event:	8th World Conference on Photovoltaic Energy Conversion
Session:	3DV.1.6
Pages:	803 - 806
ISBN:	3-936338-86-8
Paper DOI:	10.4229/WCPEC-82022-3DV.1.6
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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The interconnection technology for solar cells is an important component in the PV module production - not only for module reliability but with respect to the sustainability of the PV industry as well. We are proposing the interconnection technology “TECC Wire” (TECC=Thermoplastically and Electrically Conductive Coating) which is a new low-temperature method – and which avoids the usage of any rare or hazardous materials. As rare or critical materials in the PV industry are rated such as silver, bismuth, lead and indium because global resources are considered to be too limited or too expensive for the terawatt production level. And the usage of lead does not comply with the RoHS (Restriction of Hazardous Substances) directive. Although PV modules are still exempt from this directive, efforts to avoid using lead as a solder alloy are consensus in the industry. TECC-Wire is conceptually an improved stage of the multi-busbar or multi-wire concept. However, it allows to further reduce the consumption of silver for the solar cells metallization, and it even enables the vision of totally eliminating silver from solar cell production. The TECC wires have a similar copper core that is typically used for multi-busbar soldering of solar cell – but it is coated with an electrically conductive adhesive instead of a solder alloy. The filler material to achieve the electrical conductivity is based on non-silver particles. The recently built semi-automated stringing machine attaches the TECC wires precisely and in a defined manner. It allows us to build and test standard module configurations. The long-term reliability tests have already passed 3x IEC requirement. After 3000h damp heat test the degradation of the small modules is below 5%. In thermal cycling test the results after TC600 are around 5% for different solar cells. The peel strength is about 1.5 N/mm contact area over the entire solar cell – which is comparable to a solder joints. The homogeneity of the peel strength along the entire surface of the solar cells is remarkable, as the wires adhere to any surface and not only to the printed fingers.