The long-term stability of PV modules is the key for PV systems to be able to output power continuously. The backsheet, as an important part of the PV panel, protects the cells, but there are some common problems in the production and later use process. The following is a list of common problems with PV backsheets that Maysun Solar has compiled for you.
In the lamination process of PV module, two layers of adhesive film are used to bond the solar cells, making the solar cells and glass and backsheet together as one. Two layers of adhesive film will generally have a layer of short-wave ultraviolet light will need to be cut off. The backsheet itself has some resistance to the UV intensity of 300nm-380nm, but some of the backsheet will still yellow under UV light, resulting in the destruction of the molecular components of the backsheet layer, and the overall performance of the backsheet decreases, while the reflectivity of the backsheet decreases, affecting the overall output of the module.
Fluorine-containing materials have their own UV resistance when not otherwise treated. If both adhesive films do not cut off short-wave UV light, the UV light will directly cause the backsheet on the bottom layer to turn yellow. The yellowing of the backsheet will reduce the reflection of sunlight, which in turn will affect the solar cell's absorption of sunlight and ultimately reduce the module's power output.
The location of the hot spot of the cell and the location of the invisible tape are both prone to backsheet bulging, especially when the two locations overlap, which is mainly due to high temperature causing material vaporization.
During the application of the module, part of the sunlight absorbed by the cell itself will be converted into heat energy, causing the internal temperature of the module to rise, and the UV absorber inside the EVA will convert the absorbed UV light into part of the heat energy, which will be distributed to the interior of the module.
Generally speaking, the maximum working temperature of the normal module is between 70℃-80℃. According to the test data, the temperature increase will have an impact on the power output of the module, and for every 1℃ increase in the temperature of the module itself, the output power of the module will be reduced by about 1W accordingly.
3. Air bubbles
The backsheet strips cause a large gradient between the converging strips, and the laying employees do not put the EVA strips into place, causing the EVA to be not well filled. During the later use of the module, the bubble will gradually expand and the material around the bubble will oxidize and deteriorate, which greatly affects the service life of the module.
There are many cases of scratches: 1. the raw material itself; 2. when transported on the transmission line, there are sharp objects that cause scratches on the backsheet; 3. the trimmer causes damage to the backsheet in the trimming process.
The main role of the backplane in the components are moisture-proof, dust-proof, and insulating. Scratching the backplane of the component its moisture resistance is greatly reduced, which will accelerate the oxidation of the component, and the anti-insulation performance will reduce the safety performance of the component. Scratches will also increase the water permeability of the backsheet, too much water vapor inside the module will directly lead to the corrosion of the internal circuit, long term use, the module will lose power generation performance, the internal circuit will also be destroyed due to serious oxidation, the life of the module is cut off.
If your home PV backsheet has these problems, please contact the brand company you purchased it from as soon as possible. In addition to backsheet problems that can cause PV power loss, there are many common problems that can prevent a PV system from generating power, which can be viewed by clicking the button below.
Maysun Solar, as a PV module manufacturer with 15 years of professional experience, conducts a variety of tests during the production process and can provide you with high quality solar panels, click the button below to contact us for a product quote.