KREMPEL launches new backsheet for polyester film photovoltaic modules

Recently, KREMPEL provides photovoltaic module manufacturers with a high-quality solar photovoltaic backsheet. Its high quality can ensure that expensive photovoltaic modules will not fail due to environmental factors for decades. Strict material testing confirms the quality of KREMPEL products and their traceability over the years. In addition to standardized material labels, the company also provides customers with personalized permanent laser labels according to their needs.

In the process of producing the multi-layered AKASOL® solar photovoltaic backsheet, KREMPEL deliberately used only the preferred materials, and KREMPEL follows the customer first. Klaus Bernhardt, manager of KREMPEL's solar materials department, said that many major solar module manufacturers provide a 25-year quality guarantee for their photovoltaic module products. Without good product protection, its service life is easily affected by environmental factors. Compared with the total cost of the expensive photovoltaic module, the cost of the solar backsheet only accounts for 3-5%.

The protection function of solar photovoltaic backsheets must take into account various environmental factors, such as ultraviolet radiation, moisture, temperature changes, dust, corrosive gases, etc. Solar backsheets not only need to provide the best protection for photovoltaic modules, but also must be able to support the characteristics of existing photovoltaic systems, such as the maximum system voltage of 1000V. Only the multi-layer design of AKASOL® laminated products can fully meet these different material requirements.

Karlheinz Brust, Technical Manager for Solar Materials at KREMPEL, explains: "For the middle layer of the solar backsheet, we use polyester film with good insulating properties. This guarantees the requirements of up to 1000V required for partial discharge stability of the system voltage of various solar modules. However, polyester film is very unstable under UV radiation, so we protect it with fluoropolymer film. Fluoropolymer film is much more expensive than polyester film, but it can undoubtedly protect polyester film from UV radiation in a long time."

Internal tests also provide evidence for this. KREMPEL's R&D laboratory in Kuppenheim, Germany, tested the stability of fluoropolymer and polyester films: exposed to UV light for 8 hours at 60 degrees Celsius, then soaked in water for 2 minutes, and then simulated condensation for 4 hours at 50 degrees Celsius. These tests were repeated until 3,000 hours. The test results confirmed that fluoropolymer films are more stable than standard polyester films. The polyester film reacts to UV light and changes color significantly, indicating that the molecular chains are broken. The broken molecular chains change their chemical, physical and electrical properties, and the material becomes brittle.

Fluoropolymer membranes demonstrate advantages that have long been underestimated: extremely low flammability and limited flame spread.

This is why the inner polyester film of AKASOL® solar backsheets is usually protected by a fluoropolymer film laminated on both sides. In addition, KREMPEL also offers a UV-stabilized primer layer that can replace these two layers.

Solar module manufacturers can rely on KREMPEL's quality assurance without a doubt. For three years, KREMPEL has been the only photovoltaic backsheet manufacturer to mark the edge of the material with clearly legible numbers. If permanent traceability of this special laminate is required, laser labels are also available. These are applied on the outside of the permanently visible part of the AKASOL® laminate and can be designed individually according to customer requirements.

Figure 1: AKASOL® material structure design