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You’re probably here because you’re asking the question, “How are solar panels made?”
The importance of alternative energy sources should end our dependence on harmful fossil fuels.
Renewable energy such as solar, wind, and hydropower can sustain the world for thousands of years if used properly and effectively.
Solar energy is at the forefront of the energy transition.
Countries such as China, India, and the US are heavily investing in solar power generation and installation of up to 4 million solar panels in massive solar parks.
These many panels are enough to power a city.
The rapidly advancing technology and the affordability of solar panels contribute to their high demand.
Solar panels are a typical example of man-made technological marvels.
They should provide clean energy for generations.
How Are Solar Panels Made?
How are solar panels made and what’s the science behind these potentially world-changing instruments?
Solar Energy vs. Solar Power
The sun, scorching and blinding in its radiance, has been empowering the Earth for approximately 4.5 billion years.
181 years later, environmentalists and nations across the world focus on renewable energy to create a sustainable society.
Before diving into the explanation of what makes up a solar panel, let’s first differentiate between solar power and solar energy.
People use the terms interchangeably.
However, solar energy refers to the energy that the sun radiates.
It’s the most abundant renewable energy we can harness from a recurring source and a viable ingredient towards a greener future.
Solar energy systems, like solar panels, capture the sun’s energy and convert it into electric or thermal energy.
Solar power, on the other hand, implies the conversion of the sun’s energy into electricity.
With these two important terms defined, let’s see how solar panels are made – one part at a time.
What Are Solar Cells?
Solar panels make their magic by simply absorbing sunlight with the help of photovoltaic (PV) or solar cells.
Solar cells form in crystalline silicon wafers that allow the generation of electricity once the sunlight hits them.
These solar cells generate direct current (DC) energy to a solar inverter.
Immediately, the solar inverter converts the direct into alternating current (AC) and creates usable energy.
This is how a naturally recurring source provides energy perfect for daily consumption.
Solar cells made up of semiconductors consist of silicon elements abundantly found in silica sand or silicon dioxide.
But how did people discover that silicon can convert solar energy?
Russell Ohl and other notable scientists from Bell Labs discovered a better way to produce solar cells from an abundant and durable element: silicon.
In 1940, Ohl, a Bell Labs researcher, advanced the study in solar cell technology by observing a cracked silicon sample that showed flowing current when exposed to light.
However, it will take 14 more years for scientists at Bell Labs to confirm that a silicon solar cell can tap into the limitless power of the sun.
The interaction between silicon’s conductive properties and light stir electrons into motion.
This creates an electric flow that triggers a photovoltaic effect, which is how solar panels work.
Types of Solar Cells
There are differences in the foundation of cell types and their electricity output or solar efficiency.
Solar cell efficiency and solar panel efficiency are two different things.
For now, let’s examine the solar cell efficiency generated by n-type and p-type solar cells.
P-type and n-type solar cells
The major distinction between the two is the number of electrons each cell has.
A p-type solar cell uses boron that has one electron less compared to silicon, which makes it positively charged.
In contrast, an n-type solar cell has a negative charge as it uses phosphorus.
Phosphorus has one more electron than silicon.
In 1954, researchers from Bell Labs worked on n-type solar cells.
However, p-type solar cells took the lead in the market for at least four decades.
Because of its resistance to radiation and degradation, solar energy was mainly used in space research.
The space race progressed solar research.
It advanced it from strictly space-related usage to the power usable at residential homes and greenhouses.
Nowadays, manufacturers prefer n-type solar cells because of their immunity to boron-oxygen defects.
This defect results in light-induced degradation (LID) of silicon devices that creates a loss in solar cell efficiency during the first hours of exposure to the sun.
Therefore, P-type solar cell efficiency is limited by boron-oxygen defects.
Once exposed to the sun, in the first few hours, cells can lose their performance by approximately 1-3% or even more.
Nonetheless, p-type solar cells are still common in the production of solar panels.
Still, most consider n-type solar cells as superior.
The Role of Solar Cells
Testifying silicon’s efficiency in solar cell technology, the element’s different cell structures are responsible for the present-day solar panel manufacturing.
Silicon appears as monocrystalline (single-cell) and polycrystalline.
The difference between these two silicon cell structures depends on the process that creates them.
The cellular structure is also an instant indicator of energy efficiency rate, aesthetic, and overall performance rate of a solar panel.
With that said, let’s get to know these different kinds of solar cells and panel types available now in the market.
Monocrystalline silicon cells have the highest efficiency but come at a higher cost.
That’s why solar panels made from monocrystalline silicon cells are premium solar products.
One major reason for its premium status is the involvement of the Czochralski process.
It is an intensive method of crystal growth used to obtain high-quality single crystals.
A Polish scientist, Jan Czochralski, in 1916, accidentally dipped his pen in a container filled with molten tin rather than in his inkwell.
The modern industry uses the process to develop semiconductors for advanced electronics.
Additionally, it is a crucial method that keeps the silicon purity of monocrystalline silicon cell-based solar panels.
The process starts by rotating a single-crystal seed.
Slowly, drew upwards from molten silicon, the material becomes free from impurities and creates a block of pure silicon.
It produces large cylindrical ingots cut into silicon wafers, which are crystal semiconductors vital to solar panel production.
But the four-sided cutting system of silicon wafers leaves out a large amount of original silicon waste, which adds up to the expensive cost of its production.
Monocrystalline Solar Panels
Because of the solar cell’s construction from one single crystal and the resulting high-purity of silicon, electrons within a monocrystalline silicon cell can move more freely generating a smoother flow of usable electricity when in contact with sunlight.
The energy efficiency rate of solar panels made from this material is around 15-20%, the highest and most desirable in the market.
As this panel type produces more electricity per foot, monocrystalline solar panels guarantee a space-efficient advantage along with the longevity of over 25 years.
Additionally, monocrystalline silicon cell-based solar panels tend to perform better in low-light and high-temperature conditions.
Monocrystalline solar panels are aesthetically distinct: the solar cells have a darker hue and the cut wafers are cut diagonally at the sides forming smoother edges.
This particular solar panel type also looks sleeker than its polycrystalline counterpart.
In comparison to monocrystalline silicon cells, polycrystalline silicon cells are simpler to produce.
A single silicon crystal seed produces polycrystalline, also called polysilicon and multi-silicon cells.
Melted at high temperatures, and poured in the square molds, it results in sharp edges.
This is in contrast to the smooth four-sided edges of monocrystalline solar panels.
The uneven settling of the molten silicon results in lower silicon purity, which hinders the movement of electrons in each cell.
Polycrystalline Solar Panels
The efficiency rate of polycrystalline silicon cells is around 13-16%.
It is smaller compared to that of monocrystalline silicon cells, for which they have a low-cost advantage.
Polycrystalline solar panels don’t produce as much electricity as monocrystalline ones.
For that reason, buyers usually install more polycrystalline solar panels, and they need a larger surface to maximize energy conversion.
Additionally, solar panels of this type have a lower tolerance for high temperatures.
Consequently, they are incompatible with hot climate areas.
However, because of their affordability, they are popular in the solar industry.
They provide end-users with more options, especially in residential areas.
Production of polycrystalline silicon cells also has lesser waste.
Aesthetically, they have an indistinguishable blue-ish hue and sharp edges.
Although monocrystalline and polycrystalline dominate the market in solar technology, the industry has seen breakthroughs in thin-film solar cell energy generation.
As the name indicates, solar panels made from thin-film cells are incredibly thin, flexible, and lightweight.
Thin-film solar cells, made from several layers of light-absorbing materials just 1 micron thick, are a far cry from the traditional 350 micron-thick layers of silicon wafer cells.
These light-absorbing materials can cover glass, plastic, or metal.
There are 3 types of thin-film cells:
- amorphous silicon (a-Si)
- cadmium telluride (CdTe), and
- copper indium gallium diselenide (CIGS)
Each of these cells has its advantages and disadvantages.
Surprisingly durable, thin-film solar cells also don’t require a lot of silicon.
However, this environmental advantage can be called into question with the presence of cadmium – a carcinogen.
Thin-film Solar Panels
When it comes to solar efficiency, thin-film solar panels are yet to reach the usual percentage of standard polycrystalline solar panels.
Averaging around 7-13%, this solar panel type is disadvantageous for users with limited roof space.
However, the installation of thin-film solar panels is less labor-intensive in comparison to polycrystalline and monocrystalline solar panels.
Thus, the costs of the products are much cheaper.
The production of thin-film solar panels generates less emission compared to their traditional counterparts.
For that reason, research and development studies are focusing on these panels.
Manufacturing Solar Panels
After going through the different kinds of solar cells and panels available today, let’s dive into their construction.
A solar panel consists of six main parts:
- aluminum frame,
- tempered glass,
- ethylene-vinyl acetate (EVA) film layers,
- solar photovoltaic (PV) cells,
- polymer rear back sheet, and
- a junction box.
First, silicon is gathered from silica sand or from quartz sand to get high-purity silicon.
The collected silicon melts at high temperatures and forms ingots.
As mentioned above, depending on the solar cell type, manufacturers use one of the two methods.
They either follow the Czochralski process to produce monocrystalline solar cells or pour the molten silicon in a square mold to produce polycrystalline solar cells.
After the ingot cools down, polished, and left with flat sides, it is ready for cutting into wafers.
Pure silicon is highly-reflective.
That is why an anti-reflective coating, added on the silicon wafers, prevents incoming sunlight from bouncing back.
The anti-reflective coating prevents the loss of solar energy.
Solar PV cells consist of many layers.
The most important one is the semiconductor layer.
This layer has p-type and n-type semiconductors in contact with one another.
They form a P-N junction, which is responsible for converting solar energy into usable electricity.
This process is known as the photovoltaic effect.
The manufacturer then links a number of solar cells.
EVA film layers protect the solar PV cells from weather conditions and prevent their degradation.
Other main components of a solar panel, assembled, make a finished product.
Solar panel glass types depend on the solar panel type.
Other than EVA film layers, a solar panel glass acts as a barrier to prevent dirt and outside elements from damaging the solar PV cells inside the panel.
Solar panel glasses also affect solar efficiency.
Their purpose is to maximize solar energy transmission.
In principle, stronger solar panel glass brings more stability to the product.
That’s why tempered glass is a better option for crystalline silicon solar panels.
They have a tensile strength of 120 MPa, which is significantly higher than annealed and toughened glass.
Assembling the 6 main components mentioned above creates a solar panel.
However, the solar PV cells used make all the difference.
Each component of a solar panel defines the efficiency and cost of a solar panel.
Regardless of the value, solar panels used for residential, commercial, and industrial purposes give renewable energy that is of extreme significance to the developing world today.
Who Manufactures Solar Panels?
Robotic and automated solutions make it possible to manufacture solar panels with high precision.
They also minimize labor costs and enhancing daily productivity.
To support solar panel maintenance, drones and robots clean off dust, dirt, and other obstructive elements that prevent the maximum absorption of sunlight.
Solar companies are leveling up their products to increase solar efficiency above 20%.
This makes the industry more competitive, driven to invest in solar research.
Even with the help of automation, a human workforce is essential for solar panel manufacturing.
Solar Panels Production during the COVID-19 Pandemics
The authorities ordered non-essential industries to pause operations during the Covid-19 pandemics.
Nonetheless, governments have categorized the energy industry as essential to the economy and the needs of the communities.
For that reason, most solar companies in the US produce their products with their human workforce still onboard.
Although social distancing practices are a must, production places included, the country has almost two million of COVID-19 cases and the highest death count in the world.
The National Solar Jobs Census 2018 reports over 242,000 solar workers across the 50 states.
The Solar Energy Industries Association has already proclaimed worker safety a priority.
However, the burgeoning industry of renewable energy cannot remain wholly protected from the infections.
Yet, even in these unprecedented times, the population strives to rescue a crashing economy.
Battling a pandemic and climate change at the same time, the Green Stimulus aims to create millions of family-sustaining green jobs, invest in green housing, and reduce the carbon footprint.
Even in the worst-case scenarios, the renewable energy industry will remain in the focus and a way to heal our planet.
Shifting to Solar Energy
With a growing year-on-year interest in the solar industry, research focuses on the design of new solar cells and improved solar energy conversion.
Initially, the sunlight-to-energy conversion was around 8%, but it has grown to about 22%.
Currently, the benchmark for solar efficiency is 20% for domestic and 40% for commercial and industrial purposes.
With the rate of advanced research in solar technology, perovskite solar cells, a semiconductor with excellent absorption, efficiency, and low production costs, can bring significant improvement in solar efficiency standards.
This material has the potential to create thin-film solar cells that are four times more efficient and much cheaper than their predecessors.
Consequently, shifting to solar energy is now beneficial more than ever before.
Benefits of Solar Panels
Solar energy is not harmful to the environment because, unlike fossil fuel, it doesn’t emit greenhouse gasses.
This then results in the slowdown of climate change and the reduction of our carbon footprint.
In other words, the air we breathe becomes cleaner.
As scientists estimate, solar energy is a source that will last for another five billion years.
It’s available everywhere.
Since it’s practically infinite and free, it also significantly cuts down electricity bills.
The biggest price one has to pay is the purchase and installation of the solar energy system itself.
Compared to the benefits, they come at a relatively small price.
However, how much one can save depends on factors such as the size of the solar energy system and the amount of consumed electricity.
The maintenance of solar energy systems is cheap and requires little effort.
The parts that need the most maintenance are the inverter and the cables.
Because of its convenience and environmental benefits, solar energy has many purposes.
Solar energy can also be found in common household devices such as flashlights, power banks, speakers, and mini-fridges.
With technological advancements, solar energy will become an even better option in the coming years.
The Real Facts About How Solar Panels Are Made
Silicon is the 7th most abundant element in the universe and the 2nd most abundant element on Earth.
Consequently, innovators today are trying to mass-produce solar cells with a higher efficiency rate.
We have come a long way since 1839.
After the discovery of the first photovoltaic cell, we can now manufacture up to 72-cell solar panels capable of producing 270 to 300 watts.
We now have solar parks and farms.
Private citizens install solar panels on their rooftops, and companies work on further advancement of the technology.
However, it is debatable whether renewable energy alone can power up the whole world.
Yet, we can lessen our dependency on fossil fuels that destroy the whole ecosystem.
All we have to do now is start using alternative energy sources and embrace clean energy.
As the COVID-19 pandemic continues to wreak havoc and prevent onsite work, it will not stop solar companies from digitizing their businesses and delivering contactless service to customers.
The demand for solar energy will not fade, a brighter future is still underway.