Materials Used To Make Solar Panels
If you have ever wondered what materials are used on solar panels then this article is for you. We’ll take a look at the different materials used to manufacture solar cells. This includes both the raw materials and any synthetic additives a solar panel is made from.
Whilst the materials will vary between different solar panel manufacturers, this article will give you a good overall understanding of the materials you can expect to find in the solar industry as a whole.
Frames are a key feature in the design of a solar panel. They help to hold different components together, offer protection against the elements, and help to improve durability. Most solar panel frames are made from either anodized or powder coated aluminum.
Anodized Aluminum Solar Panel Frames
Most high-quality solar panels will feature an anodized aluminum frame and using this material has numerous benefits. Most importantly, it has the ability to reflect more heat, helping to improve the overall conversion efficiency of a solar cell.
Anodized aluminum is also easy to maintain. You can periodically clean it to restore its appearance. The material isn’t affected by sunlight and will often withstand scratches better than powder coated alternatives.
The main drawbacks of anodized aluminum solar frames are that they come in just one color – silver. This can pose a challenge to architects and solar panel companies when trying to blend solar panels into the overall aesthetics of a building.
Powder Coated Solar Panel Frames
Solar panels comprising of a powder coated aluminum frame are ideal for those who prefer style over function. Most frames of this type come in black and blend in better with dark roof tiles. They can, however, come in a wide variety of colors to match different elements of a new or existing building. You can even achieve either a gloss, matt, or satin finish with the powder coating technique.
The main drawback with powder coated solar frames is that they scratch more easily than their anodized alternatives. The benefit here though is that you can repair powder coated materials, unlike scratches on anodized aluminum frames.
Backing materials are a key component in the design of a solar panel. Their main function is to increase efficiency by offering reliable electrical conductivity. From a safety standpoint, by helping to insulate the panel, they also offer protection against electric shock.
We refer to solar panel backings as photovoltaic backsheets. These often comprise a number of different materials laminated together to deliver high-performance properties. These materials can differ significantly between manufacturers.
Solar Cell Materials
Solar cells are arguably the most important feature of a solar panel. It is the solar cell that is responsible for converting sunlight into electricity through the photovoltaic effect. Let’s now take a look at the different materials that are used to make solar cells.
Crystalline Silicon Cells
Solar cells made from silicon are the most popular choice for today’s solar panels. We can separate Crystalline silicon (c-Si) into different categories based on the crystal size of the resulting silicon wafer used in a solar cell. The two most popular categories of c-Si are as follows:
- Polycrystalline Silicon – Also known as ‘multicrystalline silicon’, this type of solar photovoltaic cell is the most common. Due to its popularity and a more efficient manufacturing process (involving molten silicon), solar panels using cells of this type are often the cheapest to buy.
- Monocrystalline Silicon – This is a highly efficient type of solar cell used in premium solar panels. They generally offer more power output than rival products but are far more expensive. Solar panels using monocrystalline silicon cells feature a distinctive pattern of small white diamonds. This is due to how the wafers are cut.
Thin Film Cells
Solar panels using thin film solar cells are less common than crystalline silicon alternatives. Although they tend to be cheaper, their performance isn’t as good as c-Si technology. A benefit of thin film cells is that they are flexible and therefore slightly more durable.
Recent enhancements in thin film technology have helped to close the gap, with some thin film cells now outperforming polycrystalline silicon cells. However, the technology is still a long way off that of a monocrystalline silicon cell.
The most popular materials in thin film solar cells are as follows:
- Amorphous Silicon – This is a popular material used widely on thin film solar cells. It uses around 1% of the silicon that a traditional crystalline silicon cell contains, making it considerably cheaper.
- Cadmium Telluride – Cadmium solar cells are the only thin film product to have rivaled the performance of monocrystalline silicon cells. The drawback to this material is that it is highly toxic, causing concern regarding the disposal of old cadmium cells.
- Copper Indium Gallium Selenide (CIGS) – This is the third mainstream thin film solar cell technology. When we compare this to crystalline silicon, CIGS cells can be anywhere between 80 and 160 times thinner.
To help improve the efficiency of a solar cell, a special coating is often applied that helps to reduce reflection. Anti-reflective coatings allow solar photovoltaic cells to absorb more light and therefore increase efficiencies.
Silicon nitride is often the material of choice for anti-reflective solar cell coatings. It is applied as a film above the cell and is available in different thicknesses. You can learn more about anti-reflective coatings for silicon solar cells at pveducation.org.
Other Noteworthy Materials
The overall construction of a solar panel also features a variety of other noteworthy materials. These include the following:
- Glass – Widely used in the design of solar panels, glass can be found above conventional silicon solar cells. With thin-film technologies, the cells are usually sandwiched between two panes of glass. This is one of the main drawbacks of thin-film technologies in that the extra layer of glass can significantly increase the overall weight of the panel.
- Copper – You can find copper in various components of a solar panel. It can be used in everything from wires (including earthing cables) through to inverters that convert DC current to AC.
- Plastic – Plastic is a common feature of a solar panel. It can be used to house junction boxes that are often found on the underside of a solar panel. Junction boxes provide an easy way of connecting multiple panels together to form a single system.
Hazardous Materials Used On Solar Panels
Some of the materials used to make solar panels can be hazardous to both our health and the environment. Although not ideal, toxic substances are sometimes used to help improve the efficiency and durability of solar energy systems. The following table details some of the hazardous materials that can be found on a solar panel.
|Cadmium Telluride||Used as the key compound in Cadmium thin-film technology. Considered safe once in use, but can pose a challenge during the manufacture and disposal of Cadmium solar cells.|
|Copper Indium Gallium Selenide (CIGS)||This chemical is toxic to the lungs but is used as the key compound in CIGS thin film solar cells.|
|Anti-Freeze||Sometimes found on solar thermal systems to help avoid fluids from freezing in colder climates.|
As you will see, most of the above only concern thin-film solar technologies. Traditional silicon solar cells are considered safe, but the manufacturing of those cells does produce silicon tetrachloride – a highly toxic byproduct harmful to plants and animals. Manufacturers should take steps to reduce the amount of silicon tetrachloride that is released into the surrounding environment.
Whilst there is no denying that solar panels come with their own environmental concerns, using the sun as an energy source is still one of the best things we can do for the environment.
Summary of The Above Materials
Solar cell manufacturing involves lots of different materials. Many of these are exotic and have only achieved fame due to the emergence of the solar power industry.
The actual list of materials in a solar panel is primarily dictated by the type of solar cells it contains. As we explained in this article, these might be silicon-based solar cells or thin film cells using different materials. These might include cadmium telluride or copper indium gallium selenide (CIGS for short).