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✓ With the technology behind solar panels becoming more affordable, it is no surprise that we are finding more of them popping up on residential and commercial properties across the country.
But have you ever looked at a solar panel and thought to yourself….
I wonder how that is made?
✓ Well, if you have, you are in luck. From the extraction of raw materials to testing, in this article, we explore the process behind making a solar panel.
Types of Solar Panels
✓ Before we dive into how solar panels are made, first a note on the different types of solar panels.
✓ There are several different types of solar panels. Those that are widely available on the market include:
- Monocrystalline solar panels
- Polycrystalline solar panels
- Thin film solar panels
- Water heating panels
✓ In this article, we will focus exclusively on explaining how the first two (monocrystalline & polycrystalline) panels are made.
This is because they are the most widely used panels currently and can be found on many rooftops and in many large-scale solar installations across the globe. They are also almost identical in their manufacturing process, making it easy to explain them both in a single article.
✓ The latter two types of panels (thin film and water heating) work in different ways, which we will not be covering today.
Raw Material Extraction
✓ The very first step in making a solar panel involves extracting the raw materials required to make it.
✓ Although alternative and tandem cell solar panels are growing in popularity, the most common cell you will find in crystalline solar panels is silicon.
✓ Silicon is a highly abundant element that is typically found in sand, although can also be found in quartzite, mica, and talc. To extract the required cells, the sand undergoes a purification process that eliminates impurities, leaving high-purity silicon.
✓ Other materials such as aluminum, glass, and various polymers are also needed to create the panel’s frame and protective layers.
Silicon Ingot Production
✓ For the purified silicon to be used in solar panels, they need to be sliced into thin wafers using a diamond wire saw. But silicon can only be sliced this way once it has been converted into a silicon ingot.
✓ To do this the purified silicon is melted into a crucible and a small seed crystal is then dipped into it. As the seed crystal is slowly pulled upwards it attracts the molten silicon. This forms the silicon ingot.
✓ The ingot is then sliced, ready to be used in the fabrication of the solar cells.
Solar Cell Fabrication
✓ So, we now have our silicon wafers which we obtained by slicing the silicon ingot. But there are a few additional steps required before these can be used in a solar panel.
✓ Firstly, the wafers are chemically etched to help them absorb light better. Then, a phosphorus diffusion process is used to create a negative and positive charge separation, forming a P-N junction.
✓ A super thin anti-reflective coating is applied to the front surface of the cell. This coating will help the cell to better absorb light by minimizing light reflections, increasing the efficiency of the solar cell.
✓ Finally, metal contacts made from silver or aluminum are screen-printed onto the front and back of the cell. These contacts will facilitate the flow of electricity out of the cell, making it usable.
NOTE: This is where monocrystalline and polycrystalline differ. Monocrystalline uses a single silicon crystal during fabrication, making a more efficient cell. Polycrystalline uses multiple silicon cells (often wasted from the production of monocrystalline), making a less efficient (but cheaper) cell.
Solar Panel Assembly
✓ Once the solar cells are ready, it is time to combine them with the other components of the solar panel.
✓ The first step in solar panel assembly involves connecting the solar cells, so they can work seamlessly to generate electricity. This is typically done using a conductive adhesive or soldering technique. How the cells are connected at this stage will determine the desired voltage and current output of the cells.
✓ The cells are then connected in a series or parallel. This helps form strings and modules which can then be applied to the larger solar panel unit.
✓ A protective layer, usually made from tempered glass, is applied to the cells to encapsulate them and safeguard them from the elements. Importantly, this glass is treated with an anti-reflective layer, helping to minimize light reflection, maximize light absorption, and ultimately increase the efficiency of the solar panel.
✓ To protect the panel from moisture penetration and provide electrical insulation a back sheet (usually made of polymer) is applied to the rear side. Finally, the panel is framed using a durable material such as aluminum. This offers structural support and protects the edges of the panel from damage.
✓ The frame also plays a role in the installation process by offering mounting points which can be used to secure the panel in place.
|Read Also: Solar Tree
Quality Control and Testing
✓ Testing and quality control are a big part of the solar panel manufacturing process.
✓ Before solar panels are considered ready for sale/installation they will undergo rigorous quality control and testing procedures. These tests will assess areas such as electrical performance, durability, and the panel’s ability to meet industry safety standards.
✓ For example, solar panels will typically be tested by measuring power output, and resistance against environmental impacts, inspected for visual defects, and verified for compliance against the relevant certifications.
How are Solar Panels Made? Summary
✓ Making solar panels is a complex process. From extracting the raw materials to physically putting together the panels, each step is time-consuming, expensive, and with considerable room for error.
✓ However, although it has taken a long time for efficient and accurate manufacturing processes to be rolled out, we are now starting to see the price of solar panels rapidly drop. As technology advances solar panels will become more efficient and more affordable, making them increasingly viable as a replacement for fossil fuels.
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