RDemo – Pilot Building-Integrated Installation of MWT-TPEdge Modules at Fraunhofer ISE

Duration: June 2011 - June 2015
Contracting Authority/ Sponsors: German Federal Ministry of Economic Affairs and Energy (BMWi)
Project Focus:
© Fraunhofer ISE
Fig. 1: HIP-MWT solar cells.
© Fraunhofer ISE
Fig. 2: Facade-integrated modules.
© Fraunhofer ISE
Fig. 3: HIP-MWT solar cell.

In the last years, Fraunhofer ISE developed and patented a series of innovative PV technologies at the cell and module level on a laboratory scale. The developments promise a significant increase of the degrees of efficiency and lowered production costs. The objective of the RDemoproject was the demonstration of these technologies using an industry-oriented production process with substantial quantities and relevant formats for a building-integrated application. 70 edge-sealed modules of the TPedge technology were integrated in the facade of a new laboratory building of Fraunhofer ISE. The modules are based on HIP-MWT solar cells (high performance metal wrap through) and structured cell connectors for back contact cells. Comprehensive tests based on IEC 61215 confirm the reliability of the modules.


The HIP-MWT solar cell, a solar cell concept developed at Fraunhofer ISE with passive backside, achieves degrees of efficiency of up to 20.5 %. The production of this cell concept requires merely one additional process step compared to conventionally contacted solar cells. In the PV-TEC (Photovoltaic Technology Evaluation Center), a pilot process could be implemented that accesses industrial systems only.

Fraunhofer ISE developed and patented structured cell connectors for the electrical wiring of back contact solar cells. These limit the electrical losses by a series connection to approx. 1 %. The solar cells were wired in the Module Technology Center of Fraunhofer ISE using an automated back contact stringer.

The TPedge module technology with edge sealing was used for the first time in “RDemo” in quantities of more than 100 modules. In this patented process, cells are not laminated as usual, but fixed in an air-filled space between the panes. The frameless design without encapsulation foils promises significant cost reductions in module production. Within the scope of the project, an automated assembly was developed and demonstrated for TPedge modules.

The solar module design considers the requirements of the architectural integration into a cold facade with adjacent fiber-cement panels. Since commissioning, the module power is monitored together with important operating parameters.