Read Consulting a California failure analysis laboratory was charged with performing a root cause failure analysis of several broken PV module glass covers. The glass covers are heat strengthened glass; they have a surface compression of 4500 psi to 7000 psi. They are cemented to the solar cell panels with a transparent adhesive. A representative glass failure analysis is shown in the photographs below. The failures were initiated by minor near edge chipping damage. The presence of crack arrest lines show that, once initiated, the crack grew incrementally due to thermal stresses. Thermal stress caused the eventual overall cracking.in the glass.
