Causes of delamination in photovoltaic modules

Delamination is a problem caused by poor quality materials or by defects in the manufacturing process of photovoltaic modules. We call “delamination” the phenomenon of loss of adhesion of the different layers that make up the photovoltaic module. This defect can appear at a very early stage, even shortly after the module is installed, and become serious over the course of the module’s life.

The graph below shows the influence of various phenomena on the degradation of the power of photovoltaic modules. Delamination (blue region of the graph) is one of the biggest causes of power reduction throughout the useful life of the modules.

Why does delamination occur?

A photovoltaic module is made up of several layers of materials that are compacted in a heating and vacuum lamination process during manufacturing. Air and moisture must be completely eliminated in this process, to prevent them from remaining between the components of the finished module.

Different layers can lose their adhesion ability when manufacturing is inadequate or low-quality materials are used. Therefore, it is very important to guarantee the quality of products and use strict quality controls in the manufacturing process.

Delamination often originates during module manufacturing, when lamination does not occur perfectly. One of the causes may be when the layers do not remain for long enough in the so-called “laminator”, the equipment responsible for bonding the glass, EVA (encapsulating film), backsheet cells (protective backing) or rear glass.

Another cause is the use of low-quality materials. Especially EVA and the backsheet are prone to losing their adhesion capacity. If we also take into account permanent exposure to climatic factors such as temperature, humidity and UVA radiation, low-quality modules can start to delaminate shortly after installation.

How is delamination detected?

Unlike other types of defects, which take time to be noticed, delamination can be detected by visually inspecting the module. Delamination can be seen as changes in the color of the module, milky spots on the front or the formation of bubbles on the back.

How does lamination affect the module?

When delaminations are far from the module edge, they negatively impact performance but are not necessarily a safety concern. However, these delaminations can extend to the module edges. Delaminations at the edges can cause seal failures that allow air and moisture ingress, which will cause cell corrosion and irreversible module destruction, affecting plant integrity.

Ways to prevent delamination

To avoid this effect, it is recommended:

• Buy material from well-known and proven brands, with certified and transparent manufacturing processes;
• Care during transport. Modules are delicate equipment and must be palletized in a vertical position, among other precautions;
• Handle the module with care during installation of the material, in addition to following the manufacturer's assembly instructions;
• Check the plant regularly. In addition to permanent monitoring, it is advisable to carry out a visual inspection at least once a year and with special measuring equipment.

With all measures applied, delamination and many other defects can be effectively combatted. It's worth doing all the risk prevention work. The cost of repairing defects in solar plants increases the later they are discovered.

References

[1] Photovoltaic enemies – Delaminacion. Available in https://www.amara-e.com/enemigos-fotovoltaica-delaminacion/