Inspection Tools for Solar Technology

Currently the energy sector lives through a period of change towards alternative energy sources, which especially triggers the development in the area of solar technology. Here, solar cells and solar thermal collectors are the key components, and the producers are interested in reducing rejects and guaranteeing highest quality of the final product. Controlling and monitoring of the materials has thus to be performed throughout all production steps.

Important exemplary tasks for the process- and quality control of solar panels are:

  • Inspection of sealing bonds during the production process.
  • Monitoring of solar cell aging.
  • Detection of mechanical stress in the base material (e.g. silicon) of solar cells.
  • Characterisation of the barrier layers in solar cells.
  • Inspection of tube-absorber-bonds in solar-thermal collectors.

The aim of this project is to develop fast, robust, and simple solutions to resolve, among others, the above mentioned problems of the solar industry. To achieve this goal we will concentrate on the techniques and methods already available within the consortium:

  • OPTICAL COHERENCE TOMOGRAPHY (OCT) is a fast, non-invasive, and contactless optical imaging method, which employs light in the near infrared (NIR). OCT is a tomographic extension of white light interferometry and therefore well suited to image layered and micro-structured samples with a spatial resolution of less than 2 microns.
  • INFRARED SPECTROSCOPY is a contact-free sensing method which provides information on the molecular level through interaction of infrared light with the sample material.
  • TERAHERTZ TECHNOLOGY uses the electromagnetic spectrum with wavelengths ranging from 30 µm to 3 mm for material characterisation and testing. Spectral and space-resolved data can be used to detect composition and defects of layers and bulk material.
  • LASER ULTRASOUND: With the aid of contactless high resolution laser ultrasound it is possible to analyse the geometrical and/or elastic properties of thin films and layered structures, including their bonding and adhesion characteristics.
  • DIGITAL IMAGE PROCESSING: Imaging sensors in the visible range (colour and monochrome), NIR, and IR, as well as electroluminescence sensors are used together with innovative algorithms to reach zerodefect solar energy product fabrication and function checks during operation.
Fig.1: OCT volume image (4 x 4 x 0,4 mm³) of the carrier layers and a contacting layer (with inclusions) of an organic photovoltaic cell.

The consortium, consisting of RECENDT, ASiC and JOANNEUM RESEARCH, has a vast experience and know-how in the application of these methods in the different fields of non destructive testing, as, for example, the determination of layer thickness (OCT, LUS, IR), chemical composition (IR, THz), and mechanical characteristics (LUS, OCT, THz). These techniques have not been applied yet to tackle the above mentioned problems of the solar industry. Hence they will be enhanced and adapted specifically towards the needs of this industry sector, providing a platform of tools to achieve enduring advantages in terms of price and quality.

This project is funded by the bmwfj (Ministry for Economy, Family and Youth) under the scope of the RSA - Research Studios Austria, processed through the FFG (Austrian Research Funding Agency).

Project duration: 01.10.2011 - 30.09.2014

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