Crack detection in photovoltaic cells using electronic speckle pattern interferometry

Tzu Kuei Wen*, Ching-Chung Yin

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This paper presents a full field nondestructive testing method to inspect the micro-defects embedded in photovoltaic (PV) cells by using electronic speckle pattern interferometry. The edge-clamped solar cells were heated to induce thermal deflection. Interference fringe enhanced by speckle patterns correlated to thermal deformation were determined by subtraction of two pictures recorded at different temperatures and image processing technique based on Fourier optics. The interference fringes produced at the defect free specimen exhibit a number of polygons with regular patterns of bright and dark fringes which are concentric with the center of the specimen. The thermal deformation will be redistributed due to appearance of the defects. The heating-induced interference fringes become quite different from those of the undamaged one. Tangential discontinuities of interference fringes or locally concentric polygon patterns occur in the contiguous area around the micro-defects or damages. The application of large temperature gradient to silicon substrates will induce crack propagation and should be prevented in ESPI inspection.

Original languageEnglish
Title of host publicationFourth International Conference on Experimental Mechanics
DOIs
StatePublished - 1 Dec 2010
Event4th International Conference on Experimental Mechanics - Singapore, Singapore
Duration: 18 Nov 200920 Nov 2009

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume7522
ISSN (Print)0277-786X

Conference

Conference4th International Conference on Experimental Mechanics
CountrySingapore
CitySingapore
Period18/11/0920/11/09

Keywords

  • Electronic speckle pattern interferometry
  • Micro-defect
  • Silicon-based photovoltaic cell
  • Thermal deformation

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