IR Reflectance Imaging for Crystalline Si Solar Cell Crack Detection

Abstract

A novel, contactless, noninvasive, and nondestructive method of crack detection in crystalline Si solar cells has been developed. A thermal imaging camera detecting in the 7.5-13-μm wavelength range was used to image the specular reflection of an IR source on the surface of a crystalline Si cell. The surface distortion caused by the presence of a crack was found to affect a change in the local surface normal, a phenomenon exploited to observe the change in specular reflection and the resultant distortion captured in an IR thermal image. The system has been found to reliably and reproducibly reveal cracks in Si cells that are not observable at visible wavelengths. The detection rate and temperature operating range were found to be readily tailored to the requirements of different manufacturing and inspection environments.

Ultrafast High-Resolution Solar Cell Cracks Detection Process

“…In order to verify the effectiveness of the proposed micro crack detection technique, the obtained results have been compared with multiple [6] and [21][22][23][24] well-developed micro cracks detection methods. A summary of the comparison is shown in Table I.…”

“…Other micro cracks detection techniques use thermal imaging such as the well-developed method proposed by W. Brooks et al [21]. This method esquires can identify the noninvasive and nondestructive regions of the inspected solar cell samples.…”

“…In addition, an EL reference image for a healthy/non-cracked solar cell sample is required for the ORing method extraction features purposes. Table I Comparative results between the proposed method developed in this article and the one presented in [6] and [21][22][23][24] Ref.…”

Photovoltaic Hot-Spots Fault Detection Algorithm Using Fuzzy Systems

“…3 demonstrates three different types of hot-spots. The hot-spots were inspected using a thermal imaging camera [20].…”

Evaluating Power Loss and Performance Ratio of Hot-Spotted Photovoltaic Modules

“…Fig. 3 shows an example of three different hot-spots categories, which were identified using a FLIR thermal imaging camera [19]. Initial invistigations demonstrated a correlation between the output power losses from each hot-spots category, but, in order to draw relevant outcomes and novel conclusions, each of the inspected category was modelled independently.…”