ACCOUSTIC AND ELECTRIC DIAGNOSTICS OF DEGRADATION IN PV CELLS AND MINI-MODULES

V. Schlosser*, M. Serini*, M. Váry**, V. Šály**, J. Packa**, M. Perný**,

* University of Vienna, Faculty of Physics, Strudlhofgasse 4, A-1090 Vienna, Austria

** Faculty of Electrical Engineering and Information Technology, Ilkovicova 3, SK-81219 Bratislava, Slovak Republic

ABSTRACT The aim of this work was to find the possibility to estimate the influence of forced ageing on the properties of PV photovoltaic modules. We have measured sound velocities in photovoltaic crystalline silicon PV modules before and after forced ageing. The samples were commercially available mini-modules consisted of three high efficiency c-Si cells connected in series. Investigation of electrical properties was performed also before and after accelerated ageing under increased temperature and PID. It was found that forced ageing strongly affects the sound velocity of the complete modules. It was shown that impedance spectroscopy measurement and characterization is an important tool to reveal the degradation of the solar cells due to high voltage stress and increased temperature stress.

Keywords: Accelerated Ageing, Acoustic Transmission, Complex Impedance, Potential Induced Degradation