Parts of Solar Panel System

Solar glass:

Once the solar cells have been encapsulated in EVA films, a glass sheet is placed over the front side of the panel where the cells interact with sunlight. The glass provides protection from the elements, such as weather, dust, rain, and hail. It is typically made from high-strength tempered glass, which is around 3-4mm thick and designed to withstand mechanical loads and extreme temperatures.
To meet the IEC minimum standard impact test for solar panels, the glass sheet must be able to endure hail stones with a diameter of up to 1 inch, traveling at speeds of up to 60 mph. Additionally, solar cells can reflect up to 35% of the sunlight that falls on their surface, which can negatively impact their efficiency.
To combat this, the rear side of the glass is coated with anti-reflective chemicals such as graphene, titanium dioxide, and silicon nitride. This coating helps prevent losses due to reflection and allows more sunlight to reach the cells, improving the overall efficiency of the panels.

Back Sheet:

After the solar cells have been encapsulated in EVA films and the front side of the panel has been covered with a glass sheet, a backsheet is added to the rear of the panel. This layer serves as a moisture barrier, providing mechanical protection and electrical insulation for the solar cells.
Backsheets are made of various types and grades of polymers or plastics, each offering different levels of protection, thermal stability, and long-term UV resistance. Typically, the backsheet layer is white in color, but it is also available in transparent or black, depending on the manufacturer and module design.

EVA:

EVA, short for “ethylene vinyl acetate,” is a specialized polymer used as a transparent plastic layer to encase solar cells and keep them in place during production. It is crucial for the long-term performance of solar panels as it is highly durable and able to withstand extreme temperatures and humidity, preventing moisture and dirt from entering.

The EVA layer is sandwiched on either side of the solar cells to provide shock absorption and protect the cells and interconnecting wires from vibrations and impact damage, such as from hailstones or other objects. A high-quality EVA film with a high degree of “cross-linking” is essential to ensure the longevity of the solar panel and prevent water ingress.

During the manufacturing process, the cells are first encapsulated with EVA before being assembled into the glass and back sheet.

Back Sheet:

A layer of material called a backsheet is added to the back of the solar panel. It serves as a barrier against moisture and a shield for both mechanical protection and electrical insulation. Different types and grades of polymers or plastics are used to create the backsheet, each providing varying degrees of protection, thermal stability, and long-term resistance to ultraviolet (UV) radiation. The color of the backsheet layer is usually white, but it may also come in transparent or black versions, depending on the manufacturer and the module’s design.
It forms a rare host layer of the panel providing both mechanical protection as well as electrical insulation.

Aluminum frame:  

The aluminium frame serves several purposes, including protecting the edges of the laminated section that encloses the cells, providing a sturdy structure to aid in mounting, and maintaining the panels’ shape and position. To ensure they can withstand extreme stress and loading from high winds and other weather impacts, these frames are typically designed to be lightweight, stiff, and durable.

The weight of the solar module is significantly impacted by the aluminium frame, which can be either silver or anodized black. The frame may also be coated with additional elements such as silver or nickel, depending on the manufacturer. The corner sections of the frame can be screwed, pressed, or clamped together during assembly to provide varying levels of strength and stiffness.

Solar cells:

Solar cells are the main component responsible for converting sunlight directly into electricity. They typically have a rectangular or hexagonal shape and are made of purified and crystallized silicon. The cells are connected by a network of very thin wires known as fingers/ribbons and busbars, which conduct the electricity generated from the cells to the terminals where it can be used to power appliances.
Solar cells come in various designs, colours, technologies, and configurations. These factors play a significant role in determining the efficiency and durability of the cells. When multiple solar cells are arranged together and connected with busbars and fingers, they form a solar module. These modules are available in different sizes, ranging from 60 to 144 cells or more.

Aluminum frame:

The aluminium frame serves several purposes, including protecting the edges of the laminated section that encloses the cells, providing a sturdy structure to aid in mounting, and maintaining the panels’ shape and position. To ensure they can withstand extreme stress and loading from high winds and other weather impacts, these frames are typically designed to be lightweight, stiff, and durable.
The weight of the solar module is significantly impacted by the aluminium frame, which can be either silver or anodized black. The frame may also be coated with additional elements such as silver or nickel, depending on the manufacturer. The corner sections of the frame can be screwed, pressed, or clamped together during assembly to provide varying levels of strength and stiffness.

Junction box:

The junction box is a small, weather-proof enclosure located on the rear side of the solar panel. It is designed to securely attach the cables needed to interconnect the panels. The junction box serves as the central point where all the solar cells are interconnected and must be protected from moisture and dirt.
All junction boxes contain bypass diodes, which keep the electricity flowing in one direction and prevent it from feeding back to the panels. Over time, bypass diodes may fail and need to be replaced. Therefore, the cover of the junction box can usually be opened or removed for servicing. However, as solar panel technology has advanced, junction boxes have also improved to better perform their functions. Many modern solar panels now use more advanced and long-lasting diodes and non-serviceable junction boxes.

Connectors:

Solar panels are typically linked together using MC4 connectors, which are specialized weather-resistant plugs and sockets. MC4 stands for multi-contact 4mm diameter connector, and these connectors are designed to be highly durable, UV-resistant, and capable of maintaining a reliable connection with minimal resistance at both low and high voltages, up to 1000V.
Silicone glue:
It is most commonly used in solar panels and creates a strong bond and is resistant to chemical moisture and other weather conditions.