What are micro cracks?
Silicon solar cells are made of very thin wafers, usually around 0.20mm thick. Although they have some ability to flex, they can suffer from pressure/stress induced cracks which are so small they are impossible to see with the naked eye. These are called micro cracks. The long term effect of micro cracks on panel life expectancy and performance are still being researched.
Micro cracks can be caused by poor handling of the solar cells during assembly (usually through non automated systems), or transport/ installation damage from vibration or shock if improperly handled or dropped.
It is not possible to see micro cracks during manufacture by the naked eye, but LG uses Infra-Red scanning cameras which can detect and isolate micro cracked cells during processing. Our modules are EL tested both before and after lamination. LG tests its panels for micro-cracks before leaving the factory and we keep an EL spectrum photo of every panel before it is shipped. Should a panel be detected with a micro crack by the quality control process before leaving the factory it will not be sold.
When you are assessing a solar panel, look for quality packaging and careful transportaional handling by your installer, so that micro-cracks can be avoided.