What Are the Different Types of Solar Panels?

The three basic types of solar panels used in home solar power systems are:

Monocrystalline solar panels: Made from a single silicon crystal, they are highly efficient and can convert sunlight into electricity at a rate of up to 22%.

Polycrystalline solar panels: Made from multiple silicon crystals, they are slightly less efficient than monocrystalline panels, but are generally more affordable.

Thin-film solar panels: Made from various materials, including amorphous silicon, cadmium telluride, and copper indium gallium selenide, they are lightweight, flexible, and less expensive than crystalline solar panels, but are also less efficient.

Monocrystalline Solar Panels

Monocrystalline solar panels, also known as single-crystal solar panels, are made from a single crystal of silicon grown from a seed crystal. These panels are considered the most efficient type of solar panel due to their high purity and uniformity of structure. Here is a step-by-step guide on how monocrystalline solar panels are made:

1. Silicon Ingot Production: The first step in making monocrystalline solar panels is to produce a silicon ingot. This is done by melting high-purity silicon in a crucible and slowly cooling it until it solidifies into a cylindrical ingot.

2. Slicing: Once the silicon ingot has cooled and solidified, it is sliced into thin wafers using a diamond saw. The wafers are typically between 180 and 240 microns thick.

3. Wafer Cleaning: The sliced wafers are then cleaned using chemicals to remove impurities or contaminants.

4. Texture Etching: The wafers are etched with a texture to increase light absorption. This is typically done using a chemical solution that creates tiny bumps on the surface of the wafer.

5. Dopant Diffusion: The wafers are then placed into a furnace, heated and doped with impurities to create a p-n junction. This part of the solar cell allows electrons to flow when exposed to sunlight.

6. Contact Printing: After the p-n junction has been formed, a metal grid is printed onto the surface of the wafer using a screen printing process. This metal grid serves as the electrical contact for the solar cell.

7. Anti-Reflective Coating: To further increase the efficiency of the solar cell, an anti-reflective coating is applied to the surface of the wafer. This coating helps to reduce the amount of sunlight that is reflected off the surface of the cell.

8. Cell Testing: Once the solar cells have been fabricated, they are tested to ensure they meet quality standards. This testing involves measuring the efficiency and output of each cell.

9. Module Assembly: Finally, the solar cells are assembled into modules by connecting them in series and parallel configurations. The modules are then mounted onto a frame and sealed with a protective back sheet and glass cover.

Overall, making monocrystalline solar panels is complex and involves many steps. However, the result is a highly efficient and durable solar panel.

monocrystalline solar cell
A Single Square Monocrystalline Solar Cell - Image Source: Stephan Kambor, CC BY-SA 2.5 via Wikimedia Commons

Polycrystalline Solar Panels

Polycrystalline solar panels, also known as multicrystalline solar panels, are made of silicon cells that have multiple crystals. These panels are cheaper to manufacture compared to monocrystalline panels as they require less silicon to make. Here are the general steps in the manufacturing process of polycrystalline solar panels:

1. Silicon Ingot Production: The first step in making polycrystalline solar panels is to produce silicon ingots. This is done by melting high-purity silicon in a large furnace above 1,400 degrees Celsius. As the silicon melts, it is purified further to remove any impurities. Once the silicon is purified, it is cooled to form a solid block or ingot.

2. Wafer Slicing: The silicon ingot is sliced into thin wafers using a wire saw. The wire saw uses a thin wire with an abrasive material to cut through the ingot. The wafers are usually around 200 micrometres thick.

3. Texturization: The wafers are textured to increase their surface area after the wafer slicing. This is done by etching the surface of the wafer with an acid or alkaline solution. The texturization process creates small bumps and grooves on the wafer's surface, which helps trap more sunlight and improve the efficiency of the solar cell.

4. Cleaning: Once the wafers have been textured, they are cleaned thoroughly to remove contaminants. This is done using a combination of chemicals and deionized water.

5. Doping: The next step is to dope the wafers with impurities to create the necessary p-n junction. This is done by diffusing impurities such as boron or phosphorus onto the surface of the wafer using a high-temperature furnace. The impurities create an excess of either positive or negative charge carriers, which are necessary for the solar cell to generate electricity.

6. Metalization: Once the wafers have been doped, they are coated with a thin layer of metal, usually aluminium or silver. This is done using a process called screen printing, which involves using a stencil to deposit the metal paste onto the surface of the wafer.

7. Cell Interconnection: The solar cells are interconnected using a series of soldered or welded connections after metalization. This is necessary to create a complete circuit and to channel the electricity generated by the solar cell to a central bus bar.

8. Encapsulation: Once the solar cells have been interconnected, they are encapsulated in a protective layer of glass or plastic. The encapsulation process involves sandwiching the solar cells between two layers of protective material and sealing the edges with a special adhesive.

9. Frame and Junction Box: The final step is to add a frame and junction box to the solar panel. The structure supports and protects the panel, while the junction box houses the wiring and electrical connections. Once the frame and junction box are added, the polycrystalline solar panel is ready for installation and use.

The manufacturing process for polycrystalline solar panels is complex and involves many steps. However, the result is a high-quality, durable solar panel that can generate clean, renewable energy for many years.

polycrystalline solar panel
Polycrystalline Solar Panel - Image Source: Guilhem Vellut, CC BY 2.0 via Wikimedia Commons

Thin-Film Solar Panels

Thin-film solar panels, also known as thin-film photovoltaic (PV) cells, are a type of solar panel that uses very thin layers of semiconducting materials to convert sunlight into electrical energy. These panels are lightweight, flexible, and less expensive to produce than traditional silicon-based solar panels. The basic manufacturing process of thin-film solar panels is:

1. Substrate Preparation: The first step in producing thin-film solar panels is the preparation of the substrate. The substrate is typically made of glass, plastic, or metal, and it serves as the foundation on which the layers of the thin-film solar panel are deposited. The substrate is cleaned and coated with a conductive layer, such as indium tin oxide (ITO), which will serve as the front electrode.

2. Deposition of the Absorber Layer: The absorber layer is the heart of the thin-film solar panel. It is responsible for absorbing sunlight and generating electrical energy. The absorber layer is typically made of a thin layer of semiconducting material, such as cadmium telluride (CdTe), copper indium gallium selenide (CIGS), or amorphous silicon (a-Si). The deposition of the absorber layer can be done using various techniques such as chemical vapour deposition, sputtering, or electrodeposition.

3. Deposition of the Buffer Layer: After the absorber layer is deposited, a buffer layer is applied on top of it. The buffer layer is typically made of a thin layer of a material such as cadmium sulphide (CdS) or zinc oxide (ZnO). It is used to improve the efficiency of the solar cell by creating a smoother interface between the absorber layer and the front electrode.

4. Deposition of the Back Contact Layer: The back contact layer is applied on the back of the substrate and serves as the rear electrode. The back contact layer is typically made of a thin layer of a material such as aluminium (Al), silver (Ag), or copper (Cu).

5. Encapsulation: Once the thin-film solar panel is complete, it is encapsulated to protect it from the environment. The encapsulation process involves the application of a layer of protective material, such as glass or plastic, over the front and back of the panel.

6. Testing and Quality Control: The thin-film solar panel is tested to meet the required specifications and quality standards. The panel is tested for its efficiency, voltage, current, and other parameters.

thin film solar panels
Thin-Film Solar Panels - Image Source: Photo by Ian Skor. – U.S. Department of Energy from United States, Public domain, via Wikimedia Commons

In summary, while monocrystalline solar panels are considered the most efficient due to their high purity and uniformity of structure, polycrystalline solar panels, made of silicon cells with multiple crystals, are only slightly less efficient and, in some cases the same. The difference in efficiency between the two types of solar panels is negligible. Therefore, homeowners can opt for either type of solar panel without significantly affecting their energy production. Despite the complexity involved in their manufacturing process, both monocrystalline and polycrystalline panels are efficient and durable options for solar power systems. Thin-film solar panels are made from various materials. They are lightweight, flexible, and less expensive than crystalline solar panels but also less efficient. The manufacturing process of each type of solar panel is complex. It involves many steps to create efficient and durable solar panels.

advertisement: solarquotes.com.au
Get a Free Solar or Battery Quote!
Contact

Solar Directory, Gladstone NSW 2440 Australia
Doing what I can to promote solar and renewable energy in Australia. I want to help small Aussie solar businesses increase their digital footprint.

Twitter | Facebook | Google Maps | Linkedin | Pinterest | Blog RSS | Contact | About | Add Solar Business | Affiliate Disclosure Statement