What are solar panels made out of?
- 03 Sep 2023
- 5 min
If you’ve ever made a sandwich, you’ll quickly grasp the principle of solar panel assembly. But what goes in it? Let’s take a closer look at what solar panels are made of.
Solar panel’s components: Cells, glass and frame
The key solar panel’s components include solar cells, glass, an encapsulant, a backsheet and a frame. Now let’s take a closer look at them.
Solar cells lie at the heart of every solar panel. They convert sunlight into electricity. These cells are most commonly made from crystalline silicon, a material known for its semiconducting properties. There are three main types of crystalline silicon cells used in solar panels: monocrystalline, polycrystalline, and thin-film.
• Monocrystalline cells: Monocrystalline cells are created from a single high-purity silicon crystal, allowing them to be 18–23% efficient in converting sunlight into electricity. A higher efficiency rate makes them 20–25% more expensive than polycrystalline cells.
• Polycrystalline cells: Polycrystalline cells are made from an ingot consisting of multiple silicon crystals, making them 3% less efficient but more affordable.
• Thin-film сells: Thin-film cells are made by depositing thin layers of photovoltaic material on a substrate, such as glass or metal. They are the least efficient – only 10-17%. Thin-film panels are the least durable and last for only 15-20 years at best versus 20–25-year lifespan of rigid panels. On the other hand, they are light and flexible which makes them useful in mobile installations, such as RV and boat systems.
The top surface of a solar panel is covered with tempered glass. It serves as a shield and protects cells from rain, dust, and debris, while also allowing sunlight to pass through. Heating and rapid cooling tempers the glass, making it stronger and more resistant to impacts.
The backsheet is the layer that seals the backside of the solar cells, protecting them from moisture and other environmental elements. Backsheets are typically made of polymers such as Polyethylene terephthalate (PET), Polyvinyl fluoride (PVF), Polyvinylidene fluoride (PVDF) and Polyamide (PA).
Bifacial solar panels have a layer of glass on the rear side and a transparent backsheet. It allows them to capture light from both sides and generate more electricity.
Between the solar cells, the glass, and the backsheet lies an encapsulant layer. This layer is usually made from ethylene vinyl acetate (EVA). It’s a transparent material that holds the cells in place and protects them from moisture and mechanical stress if something happens to the glass or the backsheet.
The solar panel frame provides structural support and protection to the entire assembly. Frames are typically made from aluminum due to its lightweight, corrosion resistance, and strength. The frame not only holds all the components together but also provides a mounting structure for installation on rooftops or ground-mounted systems.
Solar Installation Expert
Customers often ask: “Can you drill into a solar panel?” Drilling will probably void your warranty. If you have to, drill through the frame — there is nothing but air inside. Use stainless bolts to minimize the chance of corrosion.
Environmental issues of solar manufacturing: Is it sustainable?
Solar energy is often lauded for being a clean and renewable energy source. But like any industrial process, the production of solar panels has environmental implications.
The manufacturing process of solar panels involves silicon purification, wafer production, cell fabrication, and module assembly. These processes require a lot of electricity, over 60% of which is generated from coal. The production also requires caustic chemicals and lots of water. Luckily, solar panels only need to operate for 4–8 months to offset their production emissions.
While solar panels have a lifespan of 25 to 30 years or more, they eventually reach the end of their operational life. At this stage, it is crucial to have effective recycling and disposal systems in place to avoid adding to the electronic waste problem.
Some companies, such as Meyer Burger and REC, rely on renewable sources to power their production facilities and minimize their negative impact on the environment. They recycle decommissioned modules, returning glass, aluminum, plastics and silicon from panels back into the raw materials cycle. Hopefully, in the near future, this will become not an example to follow, but a strict standard in the solar industry worldwide.
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