Bubbles or milky areas

On the module front, this signature shows up as bubbles or as bright, milky areas. It comes from a local separation of layers, either between the front glass and the encapsulant or between the cell and the encapsulant. The affected area may be continuous or appear in spots. Its position and size depend on where the delamination started and how far it has progressed. It is found mainly by visual inspection of the module front, where it may appear alongside yellowing or browning. Small bubbles lined up along a cell crack can mean delamination is happening along that crack. Treat bubbles or delamination as a safety concern when they form a continuous path between the electrical circuit and the module edge, because water can get in and reduce insulation. Delamination in the optical path adds reflection and lowers current. This can cause current mismatch, trigger the bypass diode, and moisture can also raise series resistance. Field survey forms record the number of bubbles, their average size class and the fraction of area affected. Bubbles on the backsheet are recorded separately as a backsheet defect.

<!-- review notes

• sentence 3: support check: partial - Detection is listed as VI (visual inspection) and the front lists bubbles, delamination, yellowing, browning, but 'mainly' and 'alongside' are only loosely implied.
• sentence 7: support check: partial - The form records bubble count, average dimension and area fraction under backsheet damage, but the passages don't state that front-module bubbles are recorded with those fields; the form's bubble fields are only under backsheet, so the 'recorded separately' claim is inferred. -->