Reducing Lock-In thermography testing time in photovoltaic cells using thermal transient data
Abstract
Lock-in Thermography is a technique used in non-destructive testing to characterize defects in various materials, including electronic components and photovoltaic cells. In this type of thermography, tests are performed using a periodic signal that heats the photovoltaic cells for a long period of time, since the analysis is performed when the material reaches a steady state temperature. This work proposes a method to reduce test time, based on adjusting a curve with the thermal transient data of temperature generated during heating to estimate the thermal information of the material in steady state. Thus, after data processing, it is possible to obtain images that represent the internal behavior of the material similar to those obtained using the classical method. To compare these images, a similarity index is used, quantitatively measuring how close the image generated is to the image obtained in steady state. The use of the proposed method allowed obtaining images that represent the characteristics of the cells studied, as well as obtained in steady state, reducing the test time by approximately 80%.
Keywords
Lock-in thermography, thermal transient, fast Fourier transform, structural similarity index measure