Acoustic delamination or void map

This signature is a map, made by scanning acoustic microscopy or ultrasonic scanning, that shows where layers inside a PV module have come apart or where voids sit. It shows both whether delamination and voids are present and where they are, without damaging the module. Scanning acoustic microscopy resolves small defects better than pulse thermography. Ultrasonic scanning helps with delamination that is hard to see by eye, giving higher resolution, but it takes longer than faster screening methods. The failure mode it reveals is delamination, which can occur at any interface in the module, for example glass to encapsulant, cell to encapsulant, ribbon to encapsulant, or inside the backsheet. Delaminated areas add air gaps that reflect light and cut cell current, which causes current mismatch and can activate bypass diodes. Delamination is often visible as bubbles or bright, milky areas, so the acoustic map is mainly useful for less obvious cases.

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• sentence 1: support check: partial - Passages say SAM/ultrasonic scanning can detect delamination and voids, but nothing says the signature is a map (image) produced that way.
• sentence 7: support check: partial - Passages say delamination is visible as bubbles or milky areas and that ultrasonic scanners examine less overt cases, but not explicitly that the acoustic map is mainly useful for those. -->