• Funding institution: German Federal Ministry for Economic Affairs and Energy (BmWi – managed by PtJ within the scope of Solar-Era.Net)
  • Support code: 0325821
  • Amount of funding: € 146,480.00
  • Duration: 06/2015 to 05/2016
  • Consortium: STRE – Specialized Technology Resources España, ISC Konstanz, PRODINTEC, Gwent Electronic Materials


The aim of the project is to provide the PV manufacturing industry with a new functional encapsulation layer that integrates conductive structures. This layer will allow the production of PV modules with specially adapted back-contacted solar cells of highest efficiency. The rear contacting geometry and metallisation scheme of ISC Konstanz’s ZEBRA cell will be modified to be compatible with the CPOE (conduction path on encapsulant). After the cell’s metallisation geometry is adapted to fit the CPOE, the most important target is identifying a metallisation scheme for the cell’s rear side that allows for low series resistance on cell and module level and therefore enables low contact resistance to the CPOE. The end product will enable module manufacturers to easily change production from standard c-Si module assembly that relies on soldering to the assembly of high-performance back-contact modules. Even bifacial modules may be assembled.


The InGrid project aims to develop a way of interconnecting high-efficiency back-contact solar cells on the module level with the help of conductive structures that are embedded into the encapsulation material. A strong emphasis is thus placed on developing a new encapsulation material with intrinsic conductive structures that can replace ribbon soldering. For this purpose, the consortium will develop and investigate conductive inks suitable for the low (lamination) temperature limitations set by the encapsulant. Developing an adequate printing and sintering process for the conductive ink material placed on the substrate (e.g. EVA) will play a key role within the project.

The latest generation of highest-efficiency interdigitated back-contact solar cells (IBC), the ZEBRA cell, will provide the basis for the cells used in InGrid. This concept will be modified to suit the requirements of conductive inks in order to allow for reliable interconnection with low series resistance. The resulting novel material combination will be subject to climatic and outdoor testing that will prove the concept and longevity of the product. The objective of the project is to reach a cell-to-module loss of 2% or lower. In the medium term, costs will be reduced by 5% in €/Wp as compared to conventional c-Si modules.

Regarding processing technologies, the focus is on applying conductive inks to flexible substrates and on further developing involved materials so that they meet the stringent specifications set for mechanical strength, electrical serial and contact resistance after a typical lamination cycle.

The InGrid project thus combines product and process development and will deliver a novel module interconnection technology with superior outcome in terms of long-term stability, application and cell-to-module losses.