The process and product temperature is a very important physical indicator within almost every industrial manufacturing process. This applies to the solar industry, too.
Instrotech is offering Optris infrared cameras, used for industrial services, to achieve higher importance within the solar industry due to new developments within the area of infrared sensing technology, specifically the compact and fast PI160 for visualizing and monitoring the process, production and monitoring of solar modules.
The unit relies on numerous thermal processes.
The temperature allocation of wafers for the production of solar modules is captured during string brazing.
This assures a reliable and efficient assembling process. Temperature measurement takes place on the silicium surface which is connected to the braze point. This is how the quality of the homogeneity of the brazing is measured.
Challenges during the monitoring of the brazing processes are: the adequate local resolution and the temporally resolution, as the heating of the braze points can happen in less than a second. With a resolution of 160×120 pixels as well as a frame rate of 120 Hz for the whole picture, Optris PI160 IR camera is designed to measure according to these specs.
A further area of application for the Optris PI160 thermal imaging camera is the thermal monitoring of laminating processes after the single wafer has been brazed to a string.
A process report based on thermal monitoring can provide consistent temperature allocations across the panel area during the heating and cooling down phase.
Thus the laminating process will be less stressful for the solar cells and the laminating film, and the rate of defective panels can be significantly decreased.
Contact-free measuring infrared thermography is essential for the function control of solar cells. One possibility of the function control is the periodical modulated exposition of the solar cells with simultaneous observation with an infrared camera – the ‘Illuminated Lock-In Thermography’.
The separation of charge generated through the exposure of light into the solar cell leads to leakage at defective parts. Those result in locally bordered heating of the cell which can be detected with the Optris PI160 as a hot spot.
Another inspection method is ‘Dark Lock-In Thermography’. The solar cell is connected with the power supply unit and will than react with heat emission. The thermographical camera can support the localization of areas with low product quality by measuring the surface temperature.
ADVANTAGES OF THERMAL IMAGERS
The above mentioned applications perfectly point out the advantages of contact free thermal monitoring:
- The temperature measurement takes place without affecting the object or the process
- The temperature can be measured of moving, difficult to access or very hot objects during the moving process
- The measurement takes place in real time and so the temperature can be corrected during the process
- The process is documented via thermal videos and images which could also be part of quality audits
Modern thermal imaging cameras are extremely compact and feature a very high image frame rate of 120 Hz. It is therefore easy to integrate the users established auditing method into the ongoing processes, with concurrent testing times