Dr Schenk has developed a high-speed, non-destructive measurement of I-V curves of thin-film modules prior to the lamination step. The SolarMeasure I-V Curve Tracer evaluates the characteristics of every individual cell on the complete thin-film panel and detects local variations. These measurements can be taken in-line and the results serve as a GO/NO-GO test of whether a panel should be processed further.
Indirect metrology tests, e.g. measurement of pinhole density, layer thickness or haze alone cannot predict a solar panel’s final electrical efficiency.
The I-V Curve Tracer measurements can be correlated with preceding optical inspection data (e.g. local defects, layer thickness, haze) to characterize and improve processes. The I-V Curve Tracer offers stable and homogenous measurements without light power fluctuations across the measurement plane. Unique electrical characterization is achieved through space-resolved, wavelength-resolved and irradiance-resolved measurements. Unlike conventional flasher-tests, this measurement can be performed in-line before the lamination step and can, thus, serve as a GO/NO-GO tester to decide whether a panel is further processed. The I-V curve tracer can also be used as an off-line tool.
Evaluation of electrical characteristics of every individual cell on the complete thin-film panel.
The fully automated system is based on a proprietary LED illumination technology which enables an evaluation of the electrical characteristics of the entire thin-film panel, as well as the detection of local variations. The system features a three quadrant four point measurement for optimized determination of the serial and parallel resistance as well as an I-V measurement in a forward direction without light. The system comes fully automated with handling and a flexible, mechanical contacting mechanism to be integrated into a production line or to be used offline as a stand-alone tool. Next to the 2D display of I-V curves per measurement point, the analysis software offers intuitive 3D charts – cell by cell or for a cell row.
September 2011 onwards.