Listening to Materials – Material Characterization with Ultrasound

Background, Motivation and Objective

Reliability of a photovoltaic module is a key factor for being financially attractive for customers all over the world. The further reduction in manufacturing costs leads to increased demands on module components and their materials to maintain acceptable mechanical yields and module reliability. Thus fast, economic and preferably non-destructive material / component characterization and manufacturing process control methods come more and more into focus.

Statement of Contribution/Methods

In current research ultrasonic based approaches for material characterization of solar cell interconnectors – the typical electrical interconnection of solar cells in a photovoltaic module – are evaluated and compared to conventional electron backscatter diffraction techniques (EBSD) and destructive mechanical testing (tensile tests). The dispersion characteristics can be used to evaluate second order elastic parameters (Young’s modulus, Poisson’s ratio). Attenuation measurements allow an estimation of average grain size and yield strength. Acoustoelastic effects are applied to get more information about the microstructure. With help of these new measurement techniques a non-destructive evaluation of important mechanical cell interconnector properties can be achieved. These properties serve as valuable quality assurance characteristics for interconnector and solar module manufacturing lines.