Snail Trail effect: how to prevent your PV module from damage

Nowadays, solar panels are one the best way of generating clean and sustainable energy for any needs: residential, industrial, commercial, or governmental. With a life span of 25-30 years, solar panels are an investment for decades and make the quality vital for users. However, some solar panels can start to fail before they reach their expected lifespan.

If you are wondering if your panels are fine or if they need replacing or repairing, Eco Green Energy prepared for you essential facts about the Snail Trail effect and how to prevent it.

What is the Snail Trails effect?

Snail trails (snail tracks or worm marks) are lines of local discoloration that occur on solar panels after long-term usage. These brown or black lines appear near busbars on solar edges or close to microcracks.

The name of this effect origin from the illusion like snails or worms have passed over the solar panels. If the PV module has microcracks, the snail trails will appear after months of exposure of the modules to outdoor elements. Thereafter, this effect will remain constant and visible on the solar panels.

How do they appear?

Snail Trails occur after a chemical reaction on the grid of a solar panel. This reaction causes the snail trails because of the chemical breakdown. The discoloration appears through silver acetate forming, which later synthesizes into silver carbonate, and even possible to create cracks on the surface, depending on the reaction.?The silver acetate forms are due to the presence of carbon dioxide, Ag ions, and acetic acid.

What are the causes of the Snail Trail effect??

Actually, Snail trails occur after prolonged exposure of modules to outdoor elements. But the defects of the raw material and production process accelerate this effect.?

Due to?Solartechadvisor, the common material-related factors include:

- The difference in chemical properties of EVA foils and the silver contacts;

- The degradation extent of the EVA material;

- Water vapor permeability of the solar panel’s back sheet material.

Such manufacturing blemishes possibly lead to micro-cracks forming, where moisture and oxygen are easy to sip in that, increasing the chance for the Snail Trail effect. So, in general, that micro-cracks are the leading cause of snail trails on solar panels.

Effects of Snail Trails on Solar Panels

When we are talking about the consequences, the Snail Trails definitely?reduce the aesthetic appeal of solar panels. PV modules with these brownish tracks degrade the aesthetic appeal of solar panels and the surface where they are installed.?

Another reason is?low power production efficiency,?at least at 10% than panels without this problem. The efficiency reduction, however, is mainly due to micro-cracks that appear before the snail trails, but even if your solar panels have Snail Trails, the power output will be below average.

Also, Snail Trails cause resistance to the flow of current (local shunts) in solar panels, which?results in hotspots?and a reduction in solar panel efficiency.

Is it possible to prevent it??

Yes, it is possible to prevent the manufacturing stage by using better quality raw materials for production. For example, use polymer material combinations for EVA that don't cause the Snail Trail effect and optimize the number of antioxidants and stabilizers containing phosphorus.

At Eco Green Energy, we are hardly working on making sure that we produce our panels to ensure our clients the best safety and security standards as well as the highest quality. All our products are made of Grade A raw materials and?certified by TUV SUD.