Conformal thin film silicon photovoltaic modules

Abstract

A polymer composite material system and a process for encapsulation of thin film solar cells were developed for profiled roofing elements, in view of building-integrated photovoltaic (PV) applications. Amorphous silicon cells were deposited on a polyethylene naphthalate film and encapsulated with additional polymer layers in the form of a flat laminate using industrial processes. The process technology developed in this work included a pre-forming step of the PV laminate and a moulding step of a glass fibre-reinforced polyester composite. These two steps were optimised using thermo-elastic analyses, with attention paid to laminate designs and process windows compatible with the thermo-mechanical limits of the fragile active PV layers. A demonstrator with standard 1.0 m×1.8 m corrugated roofing profile, a weight of 6.3 kg and 60 W of output power was produced. The long-term endurance of the conformal modules was also validated using humidity-freeze, damp-heat and water immersion tests.

Keywords:

• amorphous silicon
• thin films
• encapsulation
• thermo-elastic analysis
• polymer composite
• building-integrated PV

Acknowledgements

The authors acknowledge the Swiss Commission for Technology and Innovation (CTI, project 9903.1 PFIW-IW) and the company VHF Technologies SA for financial support.

Notes

^†Parts of this work were presented at the 21st International Photovoltaic Science and Engineering Conference, PVSEC21, November 28–December 2, 2011, Fukuoka, Japan.