After a cell is cracked, the effect on the solar panel’s power output becomes worse and worse over the years.
Temperature changes associated with day and night cause thermal expansions and contractions that help pull apart the materials around the crack.
The video is made by running current backwards through the solar panel, so that the solar cells light up, like an LED.
The color of light that the solar cells emit is infrared (invisible to the eye), so the video is made using a special camera.
I am a bit confused by this report. How does this relate to the flex test that PV modules undergo when they are tested to IEC standard 61215?
@Gordon Howell: That’s a very interesting question for NREL. A quick search indicates that the latest information on module testing by NREL is dated 2013. Since this is new information, my guess is that an updated document might be released soon … hopefully.