A Comprehensive Guide for Solar Panel Parts and Functions

Solar panels are composed of twelve essential components that play a crucial role in converting sunlight into clean electricity. At the core of a solar panel, solar cells convert sunlight into electricity through the photovoltaic effect. These semiconductor cells generate an electrical current when exposed to sunlight, making them the essential element of solar panels. They enable renewable electrical energy production and find applications in various settings, such as rooftops and lighting systems.

Solar cells, also known as photovoltaic (PV) cells, serve as the fundamental building blocks. These PV cells capture sunlight and use the photovoltaic effect to convert it into direct current (DC) electricity. To make this electricity usable, a solar inverter is used to convert it into alternating current (AC). Ensuring stability during installation, solar racking provides the necessary support for solar panels, while a net meter allows the crediting of excess energy. Using performance monitoring, you get to track panel output, and storing surplus energy in batteries means solar energy is usable during power outages or at night. Charge controllers s are responsible for regulating voltage, while materials such as EVA and back sheets protect the panels. Aluminum frames offer structural support, interconnectors transmit electricity, and silicone glue enhances stability and protects the panels from internal moisture damage.

To function off-grid, solar panels rely on three key accessories: charge controllers, solar inverters, and battery banks. Charge controllers prevent solar panels from overcharging, which leads to power loss. Solar inverters convert DC electricity to usable AC power, and battery banks store surplus energy for nighttime usage or outages. Together, these components provide independence from the main electricity grid, enabling energy capture, regulation, conversion, and storage for later use.

While it is possible to install solar panels independently to save on installation costs, it's advisable to hire trained professionals for safety and efficiency. Installation involves setting up scaffolding, attaching roof anchors, securing solar panel mounts, installing panels, connecting the solar inverter, linking to a consumer unit, and system testing. Optionally, some users connect solar batteries for surplus energy storage. Certified installers ensure compliance with safety standards and facilitate government rebates for solar energy.

What are the parts of a Solar Panel?

There are twelve main parts and accessories of a solar panel, which are outlined below.

• Solar Panels (Cells): These are the core components of a solar panel system, responsible for converting sunlight into electricity.
• Solar Inverter: This device converts the direct current (DC) electricity generated by the solar panel into alternating current (AC), which is usable in the electrical grid.
• Solar Racking: Solar racking is a mounting system that stabilizes the solar panels on various surfaces, such as roofs, building facades, or the ground, making installation and removal easier.
• Net Meter: Net metering is a billing mechanism that allows solar panel system owners to store excess energy in the electric grid and receive credits for surplus energy sent to the grid.
• Performance Monitoring: Performance monitoring is software integrated into the solar inverter, enabling users to track the output and performance of their solar panels.
• Solar Battery Storage: Solar battery storage holds excess energy generated by solar panels for use during the night, peak energy demand periods, or power outages.
• Charge Controller: A charge controller is a voltage or current regulator that prevents solar batteries from overcharging by controlling the voltage and current from the solar panel to the battery.
• EVA (Ethylene-vinyl acetate): Ethylene-vinyl acetate is a lamination material used in solar panels to prevent moisture and dirt from entering the panel's interior while providing impact resistance.
• Back Sheet: The back sheet is the outermost layer of a solar panel, offering electrical insulation to protect the inner components from environmental conditions like rain and moisture.
• Aluminum Frame: An aluminum frame is a solar panel casing that provides structural stability to the solar cells, EVA, and back sheet components within the solar panel.
• Interconnector: An interconnector is a high-voltage transmission cable that enables the flow of electricity generated by solar panels between different electrical grids in various countries.
• Silicon Glue: Silicon glue is an adhesive used as an edge sealant in solar panels, enhancing stability and impact resistance during extreme weather conditions.

1. Solar Panels (Cells)

Solar panels are essential components in a solar system for harnessing and converting sunlight into usable electricity for household and commercial appliances. Solar panels are devices made of photovoltaic (PV) cells that convert sunlight into renewable electrical energy. Each PV cell is composed of a single layer of semiconductor material and has two layers, the positive and the negative charge carriers. Sunlight hits the cells and causes electrons to move between the layers, which generates an electrical current. The more solar cells connected within a solar panel, the more effective the panel's functionality. This collection of solar cells is also known as a solar array.

Solar panels absorb sunlight and convert it into power for use in applications such as rooftop solar panel systems, street lighting, heating systems, cameras, signage, and other energy-driven devices. Solar panels are generally positioned on rooftops for household installations or on the ground for utility-scale operations. The panels require direct sunlight in cold, sunny weather to maximize their solar generation capability and absorb the most sunlight in a perpendicular position to the sun.

2. Solar Inverter

An inverter converts direct current (DC) from solar panels into alternating current (AC), the electrical flow required by electrical circuits and domestic appliances. The three main types of solar inverters are string inverters, microinverters, and power optimizers.

String inverters are the most common type of solar inverter. Multiple solar panels are connected in a string, which then connects to the inverter. This type of solar inverter tends to be more cost-effective but sometimes suffers if a single panel underperforms, impacting the performance of the entire string. Micro inverters, on the other hand, are located on each solar panel. This setup eradicates the 'weakest link' problem of string inverters, as each panel's output doesn't affect the others. Micro inverters are more expensive but yield a higher output.

Finally, power optimizers are often seen as a middle ground between string inverters and micro-inverters. Each panel has an optimizer, which 'conditions' the DC electricity before it's sent to a central inverter. This combines the individual efficiency of microinverters with the cost advantages of string inverters. However, the requirement of a central inverter alongside individual optimizers often increases installation complexity.

Common examples of AC-powered household appliances include fridges, televisions, and air conditioning units. Solar inverters convert power harnessed from solar panels by sending DC electricity through its internal transformer, lowering the voltage and switching it to usable AC. The DC then runs through two or more transistors which rapidly turn on and off as the energy passes through the transformer’s two sides.

3. Solar Racking

A solar racking system, or solar panel mount, holds solar equipment in place during installation for stability against external forces. Solar racking is usually made from aluminum due to its higher strength and lower weight compared to other metals. Racking is put in place on the roof or the ground, with rooftop mounts having the advantage of cheaper installation costs from using the existing roof's structural support. The main advantage of ground-mounted systems is that they are easier to access and maintain without posing any safety risks.

Solar racking is integral to every solar installation because it connects the solar panel system to the roof or ground installation. As such, a solar racking system must withstand heavy winds and extreme temperatures, while transferring the weight of the solar panels to the roof structure. Weights should be evenly distributed and not fixed at specific points, so they do not put pressure on certain parts of a roof, affecting its vulnerability. Therefore, aluminum’s lightness and durability make it the most popular solar racking material due to its lightness, resistance, and durability.

4. Net Meter

A net meter is an electronic billing mechanism that credits solar energy system owners for any surplus power they export to the main electrical grid. A net meter functions when a residential solar system generates excess electricity during daylight hours. The net meter runs backward to provide a credit against whatever electricity is consumed at night or during periods when a user's energy use exceeds the system's output.

Customers are only billed for their "net" energy use, which is the actual electricity consumed. The advantage of a net meter is that it allows users to export surplus power to the grid and reduce future electric bills. The disadvantage of a net meter is that it requires a connection with the utility company, and reimburses the system user with energy credit rather than cash.

5. Performance Monitoring

A performance monitoring system is equipment working through a solar panel's solar inverter to track the overall system output for the user. A performance monitoring system includes hardware attached to a solar inverter, an internet connection, and software (like a phone application or web portal). The monitoring system displays data flowing through a solar system's inverters, allowing users to view system updates in real-time.

The advantage of a performance monitoring system is that it enables the system user to identify faulty solar panels or optimize their solar panel’s energy production. The disadvantage of using a performance monitoring system is that it requires a stable internet connection to operate, making it inoperable during a grid outage. SolarEdge and Enphase are two leading solar manufacturers with performance monitoring systems built into their solar inverters.

6. Solar Battery Storage

A solar battery storage device is equipment that stores excess energy generated from a connected solar panel for later consumption. The solar battery storage device receives surplus solar energy from a solar inverter during the day and stores it in the battery unit. The stored electricity is consumed at night, at peak energy demand periods, or during a power outage.

The advantage of solar battery storage is that it provides 24/7 backup energy for a blackout emergency or nighttime use that requires essential household appliances, such as electricity. The disadvantage of solar batteries is that they add additional components to a solar panel system that require yearly inspection and maintenance.

7. Charge Controller

A charge controller is a device that regulates the electricity entering a solar battery bank from the solar panel. The charge controller ensures that the solar batteries don't overcharge during the day and that the power doesn't flow back to the solar panels overnight and drain the batteries. Some charge controllers have additional uses, like lighting and load control, but controlling power flow is their primary function.

Charge controllers have two technologies, Pulse Width Modulation (PWM) and Maximum Power Point Tracking (MPPT). A PWM controller draws electrical current out of the solar panel at just above the battery voltage level. An MPPT charge controller draws the electrical current out of the panel at its maximum power voltage, allowing it to use more energy from the solar panel.

The advantage of using a PWM charge controller is its lower cost compared to an MPPT controller, but the disadvantage is that it is less efficient. MPPT charge controllers have the advantage of up to 15% higher average efficiency ratings than PWM controllers. Because MPPT charge controllers have more electronic components, they have a shorter lifespan than PWM controllers, resulting in greater thermal stress over time.

8. EVA

EVA (Ethylene Vinyl Acetate) is an encapsulation material used in solar panel lamination to protect solar cells from external shocks and vibrations. EVA provides mechanical support and environmental isolation necessary for solar cells and electrical wires to ensure stable electrical performance. Roughly 80% of solar panels use EVA as a solar encapsulant.

This is due to EVA's inexpensive construction costs and ability to maintain the optical connection between the solar cell and glass casing in a solar panel. The optical connection between solar cells and the EVA glass casing is essential for transforming and absorbing sunlight in solar panel systems. EVA allows solar panels to achieve an optimal connection of at least 90% and a maximum efficiency loss of just 5% over 20–30 years or more.

9. Back Sheet

The rear side of a solar panel is covered by a back sheet, usually made from polymers. The back sheet provides electrical insulation and protection for the inner components of a solar panel against environmental forces, such as rain and moisture. These environmental forces cause interior degradation in solar panels, leading to corrosion of electrical connections and potential short-circuiting.

The back sheet of a solar panel is typically made of a polymer material that keeps its shape under pressure and minimizes water-based degradation over time. A double glass back sheet on a solar panel is a viable alternative to polymers due to its low degradation rates and higher water impermeability.

10. Aluminum Frame

An aluminum frame is a solar panel casing that provides structural stability for the solar cells, EVA encapsulant, and back sheet components in a solar panel. The aluminum frame covers the entire solar panel and seals these components, protecting them from external forces such as wind, rain, and dust. These external forces damage the panel’s interior and negatively impact its performance over time. Aluminum solar panel frames are typically combined with aluminum mounting brackets to provide support to the solar panels all year round.

The main advantage of an aluminum frame is that it is lightweight, durable, corrosion-resistant, and has solid conductive properties during thunderstorms. The primary disadvantage of an aluminum solar panel frame is that it is only available in silver, posing a challenge to architects and solar panel manufacturers when trying to blend solar panels into the aesthetics of a building.

11. Interconnector

An interconnector, sometimes referred to as a DC tie, serves a crucial function in solar panels by facilitating the flow of high-voltage DC electricity between distinct electrical grids. Interconnectors are key components that connect separate AC networks or link synchronous grids. By permitting the transit of electricity between solar panels, interconnectors ensure efficient energy distribution within an entire solar panel system.

Interconnectors take various forms, including submarine power cables, underground power cables, or overhead power lines. The flexibility in their form brings about a unique advantage as they adapt to different physical and environmental constraints. This makes interconnectors an integral part of solar panels and solar systems, enhancing their overall performance and efficiency.

12. Silicone Glue

Silicone glue is an adhesive containing silicon and oxygen atoms used to seal edges on solar panels. The use of silicone glue prevents moisture from entering solar cells and connections, as well as protects conductive oxide coatings from corrosion and degradation caused by water. The combination of silicon and oxygen makes the glue ideal for solar panel use because it is water-resistant with high thermal and chemical stability. These chemical properties allow it to maintain adhesiveness and impact resistance when a solar panel experiences extreme rain, wind, and temperature fluctuations.

Using silicone glue as a solar panel edge sealant is advantageous because it has a powerful adhesive bond that is often used in applications that require flexibility or resistance to extreme temperatures and moisture. Compared to hybrid sealant materials, silicon glue has the disadvantage of being brittle, and delamination and degradation sometimes occur over time.

What is the most important part of a solar panel?

A solar cell is the most important part of a solar panel, as it converts sunlight into usable electricity. Producing renewable electricity is the main function of a solar panel, and the solar cell is the only solar panel part using the photovoltaic (PV) effect. The PV effect describes the ability to generate a usable electrical current from light photons from the Sun. Solar cells use the photovoltaic effect to absorb and transfer solar energy to power household and commercial appliances.

Without solar cells, a solar panel cannot generate electricity, and research into solar panels without solar cells is currently in its beginning stages. Currently, there is just one solar device that doesn't use solar cells: an optical battery made from glass that uses magnetism instead of sunlight to produce electricity.

Optical batteries convert solar power into usable energy at a rate of 10%, which is much lower than solar panels that convert sunlight into energy at up to 23% efficiency. As this solar power technology is in the experimental phase, modern solar panels rely overwhelmingly on silicon-based solar cells to produce electricity. Until alternative solar technologies become commercially viable, silicon-based solar cells will remain the most important component of solar panels.

What are the solar panel accessories?

The three main solar panel accessories are a charge controller, solar inverter, and battery bank. These three accessories allow a solar panel to go fully off-grid.

A charge controller is a device that regulates the voltage and current coming from the solar panels going to the battery. The charge controller ensures that the batteries do not overcharge during the day and that the power doesn’t run backward to the panels overnight, draining the batteries and making them crucial for battery protection. 

The solar inverter is a key component that transforms direct current (DC) power generated by the solar panel into alternating current (AC) power, which is used by most home appliances. This conversion allows the utilization of solar power in a home-friendly format. The battery bank stores the power that the solar panels generate during the day for use during night-time or power outages.

These three accessories allow a solar panel system to operate independently or "off-grid." They collectively enable the capture of solar energy, control and regulate this captured energy, convert the energy into usable form for home appliances, and store excess energy for later use.

Where are solar panels assembled?

Most solar panels in the world are assembled in China thanks to its access to silicon, a major component of solar panel production. Silicon is vital for constructing solar cells, which are connected in rows to form a functioning solar panel. Chinese companies use their regional access to silicon to produce solar panels on a vast scale. Seven out of ten of the world’s largest solar manufacturers are based in China, including LONGi Solar, Trina Solar, and Jinko Solar.

Solar panel manufacturing involves the creation of solar cells comprising silicon wafers. These silicon wafers are the main material used in solar panel construction. China controls more than 60% of the silicon wafer manufacturing industry, making it the main global exporter of solar panels and solar panel parts. The Chinese-owned LONGi Solar is the world’s largest solar company and produces at least 25% of global silicon wafers for solar panels.

Silicon wafers are constructed from solar-grade polysilicon, a raw material essential for allowing silicon-based solar panels to generate electricity. Over 45% of solar-grade polysilicon is sourced from the Xinjiang region of western China. Along with silicon wafers, another essential component of a solar panel is the aluminum frame. An aluminum frame is a protective casing that shields the solar panel from external debris and moisture. As with silicon wafers, China dominates the aluminum frame manufacturing industry. Most aluminum frame manufacturers are Chinese companies.

In the United States, solar panel assembly is also a significant industry, although it is not as dominant on a global scale as in China. Some of the major solar panel manufacturers in the US include First Solar (headquartered in Arizona), SunPower (California), and Tesla (California, formerly SolarCity). First Solar, has been a key player in the American solar industry, focusing on large-scale utility projects. SunPower, on the other hand, is known for its high-efficiency solar panels and has a strong presence in both residential and commercial markets. Tesla, with its acquisition of SolarCity, has integrated solar panel production into its clean energy portfolio.

How to install solar panels?

To install a solar panel, there are seven steps to follow, including setting up scaffolding, attaching roof anchors, securing the solar panel mounts, installing the solar panels, wiring the panels to a solar inverter, connecting the solar inverter to a consumer unit, and testing the solar panel system to ensure it works properly. An optional eighth step in the solar installation process is to connect the solar inverter to a solar battery for storing excess power.

The seven steps to installing a solar panel are outlined below.

1. Set up scaffolding. Scaffolding is a boarded working platform that provides safe and secure access to a rooftop, for a rooftop solar panel installation. Using scaffolding reduces the risk of serious injury due to falling from a rooftop.
2. Attach roof anchors. A roof anchor ensures that solar panels remain securely attached to roof tiles. Attaching roof anchors requires removing some roof tiles to secure the anchors to the rafters in the loft. Mounting the solar panels on the loft provides a stable foundation for enduring adverse weather conditions.
3. Secure solar panel mounts. Once roof anchors are in place, the next step is to attach the solar panel mounting system. The solar panel mount spans vertically and horizontally across the roof, supporting the base of the solar panels. The mount ensures that the solar panels stay in a fixed position while positioning the panels at an optimal angle on the roof for maximum sunlight exposure.
4. Install solar panels. Once the mounting system is established, the solar panels are ready to be installed. This is achieved by placing the solar panels on the mounting system. Once the optimum angle of the panels is determined, the installer secures the panels to the mounting system.
5. Connect the solar inverter. A solar inverter is essential for converting the direct current (DC) electricity from a solar panel into alternating current (AC) electricity. Most solar panels are pre-wired for connecting to a solar inverter by the manufacturer. The inverter is typically installed near the breaker panel, which is the main distribution point for electrical circuits in the home. Installing a solar inverter takes 4-6 hours, during which household electricity must be powered off.
6. Connect to a consumer unit. The solar inverter must be connected to a consumer unit or an energy distribution board to start producing electricity. This is done by linking a generation meter to the solar system, which monitors the amount of electricity the solar panels produce. This performance monitoring system is typically accessible through a mobile or web application.
7. Test the solar panel system. Finally, after the solar panels are attached to the rooftop and connected to the main electricity grid through an inverter, it is time to test their functionality. This is done by switching the power back on and monitoring each component of the solar system to ensure there are no faults in the solar production process.

Additionally, it is possible to connect the solar inverter to a solar battery. A solar battery is a device that stores any surplus energy the solar panels produce during the day for use on overcast days or at night. The battery is installed by attaching it to the system’s solar inverter, which occurs after the inverter is connected to the solar panels.

Can I install a solar panel on my own?

Yes, it’s possible to install a solar panel on your own if you have the expertise, parts and tools. DIY solar installation is difficult and dangerous without sufficient understanding of electrical wiring, access to parts like an inverter, and experience on roofs. In most cases solar panels are best installed by a trained professional.

The most attractive reason for installing solar panels yourself is the savings on installation costs. An installer usually charges $70 to $120 per hour for installing solar panels. Prices often vary, however, depending on location, accessibility, and demand. Since solar panel system installation is usually expensive, some customers with technical knowledge or experience install the panels themselves.

However, it's crucial to emphasize that the long-term benefits of using a licensed installer outweigh the initial savings of a DIY installation. In the United States, hiring a certified professional ensures compliance with industry standards and is even essential for claiming government rebates or incentives related to solar energy.

For those committed to a DIY solar panel installation, there are reputable guides available to assist you. Accreditation bodies like the NABCEP (North American Board of Certified Energy Practitioners) in the US ensure that solar installers are adequately trained and adhere to established codes of conduct, prioritizing consumer benefit.