Solar has entered the mainstream as the world’s cheapest energy source, leaving many people wondering how solar PV can be so efficient and inexpensive while still providing “green” energy. Answering that question means understanding how solar energy work, how solar panels are manufactured and what the parts of a solar panel are. Most panels available on the market are made of monocrystalline, polycrystalline, or thin film (“amorphous”) silicon. In this article, we’ll explain the different ways solar cells are made and what parts are required to manufacture a solar panel.
Key takeaways about making solar panels
- Solar panels are usually made from a few key components: silicon, metal, and glass
- Standard panels are either made from monocrystalline or polycrystalline silicon
- Start comparing solar quotes on the EnergySage Marketplace to see you equipment options side-by-side
What are solar panels made of?
The materials used to manufacture the cells for solar panels are only one part of the solar panel itself. The solar panel manufacturing process brings together six different components to create a functioning solar panel. These parts include silicon solar cells, a metal frame, glass sheet, standard 12V wire, and bus wire. If you are DIY-minded and curious about solar panel materials, it may even be a question of wanting a hypothetical “ingredients” list to produce one on your own. Here are the common parts of a solar panel explained:
Silicon solar cells
Silicon solar cells convert the Sun’s light into electricity using the photovoltaic effect. Soldered together in a matrix-like structure between the glass panels, silicon cells interact with the thin glass wafer sheet and create an electric charge.
Metal frame (typically aluminum)
A solar panel’s metal frame is useful for many reasons; protecting against inclement weather conditions or otherwise dangerous scenarios, and to help mount the solar panel at the desired angle.
The glass casing sheet is usually 6-7 millimeters thick, and although it is thin, it plays a big role in protecting the silicon solar cells inside.
In addition to the solar cells themselves, a standard solar panel includes a glass casing at the front of the panel to add durability and protection for the silicon PV. Under the glass exterior, the panel has a casing for insulation and a protective back sheet, which helps to limit heat dissipation and humidity inside the panel. The insulation is particularly important because temperature increases will lead to a decrease in efficiency, resulting in a lower solar panel output. Thus, PV manufacturers must go extra lengths to ensure that light is being captured without the technology being overheated.
Standard 12V wire
A 12V wire helps regulate the amount of energy being transferred into your inverter, aiding with the sustainability and efficiency of the module.
Bus wires are used to connect the silicon solar cells in parallel. Bus wires are covered in a thin layer of solder for easy soldering, and are thick enough to carry electrical currents.
How solar panels are made
Solar panels are made of monocrystalline or polycrystalline silicon solar cells soldered together and sealed under an anti-reflective glass cover. Once light hits the solar cells, the photovoltaic effect starts, and electricity is created. The five key steps in making a solar panel are:
1. Make the solar cells
2. Solder solar cells together to create a panel
3. Install a backsheet, front glass layer, and frame
4. Install a junction box
5. Quality testing
Make the solar cells
The primary components of a solar panel are it’s solar cells. P-type or n-type solar cells are a mix of crystalline silicon and either gallium or boron to create silicon ingot. When phosphorus is added to the mix, the cells are able to conduct electricity. The silicon ingot is then cut into thin sheets, and coated with an anti-reflective layer. Then, thin slits are cut in the cells to funnel the flow of electricity.
N-type vs. P-type solar cells
The difference between p-type and n-type silicon cells is in their chemistry. P-type cells are positively charged due to a layer of boron, whereas n-type silicon cells are built on bases of phosphorus, giving them a negative charge. N-type cells are generally more efficient than p-type cells due to the way they interact with incoming light. Unlike p-type cells, n-type cells deteriorate faster when exposed to a lot of light, like in the summer months.
Solder solar cells together to create a panel
After the phosphorus gives the silicon wafers their electrical charge, metal connectors link each solar cell in a process called soldering. The number of cells soldered together at once depends on how big the solar panel is being manufactured to be. For reference, 60 cell-panels are standard size, and 72-cell panels are generally used for commercial projects.
Install a backsheet, front glass layer, and frame
A backsheet is installed to the bottom of the solar cells for protection, usually made from an ultra-durable plastic material. Next, a thin glass sheet is installed on top of the solar cells to filter the sunshine into the solar cells. These parts are held together by a glue called ethylene vinyl acetate (EVA). All of these components are confined by a metal frame which latches onto mounting clamps on your roof.
Install the junction box
The junction box protects a solar panel’s wiring from damage in order to keep the flow of electricity moving from the panel to its inverter, preventing electricity from reversing direction. This functionality is important for times when a solar panel isn’t producing electricity, because that panel will try to consume energy instead. The junction box doesn’t allow any reversal of electric flow, so your solar panels can function correctly.
Each solar panel to hit the market is tested under Standard Test Conditions (STC) to ensure that the panels meet their projected outputs, efficiencies, and everything else the manufacturer promises in their technical specification sheet. Panels are put into a flash tester where “standard” conditions are simulated: 1000W/m2 irradiance, 25°C cell temperature and an air mass of 1.5g. If it passes, the solar panel is ready for shipment and installation.
The photovoltaic affect, monocrystalline, polycrystalline, and thin-film panels
Solar photovoltaics are made with a number of parts, the most important of which are silicon cells. Silicon, atomic number 14 on the periodic table, is a nonmetal with conductive properties that give it the ability to convert sunlight into electricity. When light interacts with a silicon cell, it causes electrons to be set into motion, which initiates a flow of electricity. This is known as the “photovoltaic effect.”
However, silicon cells alone can’t provide electricity for your home. They are paired with a metal casing and wiring, which allow the solar cell’s electrons to escape and supply useful power. Silicon comes in a number of different cell structures: single cell (monocrystalline), polycrystalline or amorphous forms, most commonly associated with thin film solar panels.
Solar panel manufacturing process
Monocrystalline solar panels are produced from one large silicon block and are produced in silicon wafer formats. The manufacturing process involves cutting individual wafers of silicon that can be affixed onto a solar panel. Mono-crystalline silicon cells are more efficient than polycrystalline or amorphous solar cells. Producing individual monocrystalline wafers is more labor-intensive, and consequently, they are also more expensive to manufacture than polycrystalline cells. Monocrystalline cells have a distinct black aesthetic and are often associated with the sleek look of SunPower’s premium panels.
Polycrystalline solar cells are also silicon cells, but rather than being formed in a large block and cut into wafers, they are produced by melting multiple silicon crystals together. Many silicon molecules are melted and then re-fused together into the panel itself. Polycrystalline cells are less efficient than monocrystalline cells, but they are also less expensive. They have a blueish hue that is often associated with the aesthetic of SolarWorld solar panels.
Finally, amorphous silicon cells create flexible solar panel materials that are often used in thin film solar panels. Amorphous silicon cells are non-crystalline and instead are attached to a substrate like glass, plastic or metal. For this reason, thin film solar panels are true to their name: they are lean and bendable, unlike a standard panel. Though an ideal use case for versatility, amorphous solar cells are very inefficient compared to mono or polycrystalline cells. First Solar is best known for manufacturing thin-film panels in the U.S.
After the unique type of solar cell is made, solar panel manufacturers finish the process by connecting the electrical systems, adding an anti-reflective coating to the cells, and housing the entire system in a metal and glass casing.
Can you make your own solar panels?
For anyone wanting to install solar who is considering a do-it-yourself route, there are a number of factors to consider such as warranties, the longevity of output, efficiency and overall cost. To get a full sense of this breakdown, check out our article on the pros and cons of DIY solar. If you’re looking for a personalized estimate for what a solar installation would cost based on your specific location and roof type, try our Solar Calculator. For homeowners interested in receiving quotes from local, pre-screened installers, check out the EnergySage Solar Marketplace.