Backsheets are a vital part of solar panels as they protect the solar cells from the elements. Knowing the most popular backsheet material for solar panels can help you make the best decision when purchasing solar PV modules
Because the back of a solar panel serves an essential function, it must be well-constructed from high-quality materials. A poor backsheet can shorten the lifespan of a solar panel, reduce its efficiency, or even cause solar panel failure. This guide reviews the most popular backsheet material for solar panels and answers questions such as what is a solar module and what materials are used on solar panels.
High powered PV systems and the new Enphase IQ8 microinverter keep solar systems running optimally at peak performance.
What Is the Most Popular Backsheet Material for Solar Panels?
Backsheets protect fragile solar panel cells from multiple elements and protect people and animals from the electric charges in the cells. To accomplish these important tasks, most backsheets are made of multiple layers of plastic film. The most popular backsheet films are:
- Polyethylene terephthalate (PET)
- Tedlar polyvinyl fluoride
- Kynar polyvinylidene fluoride
The most popular combination of polymer films for backsheet material is TPT. A TPT solar backsheet layers Tedlar, PET, and Tedlar again. KPK (Kynar, PET, Kynar) is also common.
PET is present in both combinations making it the single most popular backsheet material. Before we go more in-depth about the value of double fluoropolymers, look at the other materials used to make solar panels.
What Are Solar Panels Made Of?
The backsheet is just one of many parts of a PV module. Solar panel materials include glass panels, silicon cells, metal casing, and brackets. Here are common solar panel layers in order from top to bottom:
- Metal frame
- Tempered glass
- Encapsulant
- Solar cells
- Backsheet
The core of any solar panel is the photovoltaic (PV) cells. What are the materials used in solar cells?
The cells in a PV module are made of silicone. Silicone is produced from sand and refined to create solar wafers. The solar wafers are then processed to become PV cells, and the PV cells are what convert sunlight into energy. They are the semiconductors in solar panels. All the other parts of the solar panel are designed to protect the solar cells and maximize their efficiency.
What metals are in solar panels besides silicone? Numerous metals are used in different solar panel parts. The frame and brackets are usually aluminum. The solar cells also contain copper, silver, tellurium, and zinc.
Why is PET the Most Popular Solar Backsheet Material
While Tedlar and Kynar materials are strong and great electrical insulators, they are more expensive than PET. Layering PET between these fluoropolymers helps keep the costs of solar panels down without compromising quality.
PET is a thin, commonly-used plastic. Most people encounter it regularly in the form of plastic water bottles or take-out food containers. A multilayer backsheet with PET in the middle is the most popular backsheet material for solar panels for many reasons:
- Transparency: PET is naturally clear, allowing sunlight to reach the solar cells from both sides of the panel.
- Resistance to Elements: PET can withstand harsh elements, especially when combined with Tedlar.
- Thermal Resistance: PET is an insulator that resists heat flow to ensure the solar panel converts sunlight as efficiently as possible.
- Lightweight: This material is light, strong, and easy to safely transport.
- Availability: Because of its popularity for many common household items, PET is a readily available material
What Does Backsheet Material Do?
The backsheet material is the bottom layer of the solar panel, and it can be rigid or flexible depending on the design of the module. However, even with flexible solar panels, the backsheet must be strong enough to protect the solar cells and contain the solar cell voltage.
The backsheet material acts as a barrier, keeping the electrical charge inside the solar panel and elements from the surrounding environment out. All solar panels must have a backsheet. Otherwise, the electrical charge in the solar panel could become dangerous.
Why is the Backsheet Important?
Backsheets protect solar cells from the following elements and environmental conditions:
- Moisture and humidity
- UV radiation
- Precipitation
- Dust and sand
- High winds
- Extreme temperatures
- Scratches and other damage
Regular maintenance can prolong the life of your solar panel backsheet and improve its efficiency.
Does Solar Panel Backsheet Need Replacing?
Solar panels are highly reliable and are built to last 25-30 years. Research from the U.S. Department of Energy found that the solar panel failure rate is only .05%. In the rare event that a PV module does fail, backsheet failure is a common solar panel defect. So, what happens if one solar panel fails?
If this happens, a solar system installed by Sun Badger will continue to work, except for the faulty panel because solar modules connect in parallel using Enphase microinverters.
Sun Badger is an Industry Leader for TPT Backsheet Solar
Sun Badger Solar provides residential and commercial solar power systems using only the best Tier One solar panel with TPT backsheets. That’s why our panels last up to 30 years with little maintenance required. Reach out to our solar industry experts today to get a custom estimate for any solar power project.
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