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The solar cells in photovoltaic (PV) panels capture photons from sunlight, and the balance of system (all the required components of a solar power system aside from the panels) converts solar energy into household (AC) electricity.
But how does the whole process work?
Read on to find out how solar cells function and which type of cell is right for your specific electricity consumption needs.
What Are Solar Cells?
Solar cells are an essential component of solar (photovoltaic) panels that capture energy from sunlight. Solar cells are thin semiconductor devices composed of layers of material — usually silicon — and conductive metal contacts.
These cells convert sunlight into electricity through a process known as the photovoltaic effect. The photovoltaic effect is the foundation of modern solar technology — that’s why solar panels are commonly known as photovoltaic, or PV, panels.
(Source: Energy Education)
How Do Solar Cells Work?
Solar cells work because of the photovoltaic effect — and it’s nothing new! First discovered in 1839, the photovoltaic effect is what makes solar panels and solar power systems of any size work.
Without the photovoltaic effect, there would be no such thing as solar-generated electricity.
(Source: Energy Education)
Solar cells capture sunlight. Inside each cell, two semiconductors — p-type and n-type — form a p-n junction to create an electric field. Sunlight is made of photons — minuscule bundles of electromagnetic radiation — better known as solar power. Using the photovoltaic effect, the p-n junction inside each solar cell converts the sun’s photons into electricity.
Solar panels can (and typically do) contain more than one solar cell. For example, a 400W rigid solar panel generally contains over 150 individual PV cells. Beneath the panel’s surface, the solar cells are interconnected, and the combined solar energy they capture is output as DC current.
However, solar panels don’t generate household (AC) electricity on their own. They must be connected to a portable power station or other balance of system (BOS). No matter what size your solar panel array is or which BOS manufacturer you choose, a solar power system must contain the following components:
- Solar battery (optional for grid-tied systems)
- Charge controller (MPPT or PWM)
Depending on whether you buy an all-in-one solution like EcoFlow’s DELTA Pro or build a DIY solar power system, your BOS may contain additional components and features like a smart battery management system.
EcoFlow’s solar generators include all of the above and also offer many additional features, including remote control with the EcoFlow smartphone app. You can monitor and control your portable power station or whole home generator from anywhere with an internet signal.
Opting for a plug-and-play solar power system — such as a portable power station or Power Kit — and rigid, flexible, or portable solar panels offers numerous benefits, not least of which is simplicity. Additionally, you don’t have to worry about the compatibility issues that often arise when you purchase solar panels and separate BOS components from different manufacturers.
Types of Photovoltaic Solar Cells
There are three primary types of solar cells available for residential use: monocrystalline, polycrystalline, and thin film cells. As outlined above, the solar cells are interconnected beneath the surface of the solar panel.
Here’s a brief overview of the three types of consumer solar panels:
(Source: American Solar Energy Society)
Monocrystalline Solar Panels
Monocrystalline PV panels are by far the most established option on the market. Sleek and streamlined, the solar cells inside a monocrystalline PV panel consist of a single crystal of highly durable silicone.
The silicon crystals are grown in a lab, and solar panel manufacturers cut and shave them into octagonal-shaped silicon wafers. Once the cells are processed into wafers, they are placed inside a solar panel frame. Their consistent octagonal shape makes it possible to fit more cells into a smaller frame than with other cell types.
The downside of this manufacturing process is that it generates significant waste. Still, monocrystalline solar panels are often preferable because of their higher efficiency compared to other PV cell types.
Monocrystalline solar panels also typically cost more than polycrystalline panels. But the additional upfront investment translates to more significant savings on electricity bills over time due to optimal efficiency. In this context, efficiency is a PV panel spec that measures how much of the sunlight that hits a solar panel is converted into electricity.
Mono PV panels average around 20% efficiency. EcoFlow’s solar panels boast an industry-leading 23% efficiency rating. The higher the efficiency, the more electricity is generated using fewer panels and taking up less space.
Polycrystalline Solar Panels
Polycrystalline panels are comprised of multiple polycrystalline fragments melted together, resulting in their distinctive checkerboard appearance. They’re less aesthetically pleasing, less intensive to make, and also produce less waste. These and other factors make polycrystalline PV panels slightly more affordable than monocrystalline.
But the lower sticker price comes at a cost. Poly panels offer less efficiency than mono PV panels — partly because the movement of electrons is restricted because each cell comprises many silicon crystals instead of one.
Polycrystalline PV panels typically have an efficiency rating of +/-15%. Mono solar panels offer up to 23%. What does that mean in the real world? You need more solar panels that take up more space to generate the same amount of electricity with polycrystalline solar cells than with mono PV cells.
Even if poly panels are cheaper upfront, their lower efficiency means that you’ll need more space — and potentially more panels — than you would with mono panels with the same rated power output.
The less electricity you generate via solar power, the longer your solar payback period can potentially be. Solar payback is the point at which the money you spent on your solar panel system is equalled or exceeded by the money you’ve saved on electricity bills.
Once you’ve achieved solar payback, your return on investment really kicks in. As long as you’re saving money on your electricity bills, that cash goes straight back into your wallet.
Money saved is money earned.
Carefully weigh up the long-term benefits vs. short-term savings before making a purchase decision between monocrystalline and polycrystalline PV panels (and the solar cells within them).
Thin Film Solar Cells
Thin film solar cells are a more recent development than monocrystalline and polycrystalline cells. They don’t generate as much electricity and are significantly less efficient than mono or polycrystalline solar panels. But they do serve well in some use cases due to unique construction, flexibility, and low dimensional profile.
Thin film panels use various materials, including silicon, cadmium telluride, and copper indium gallium selenide, to create sheets of photovoltaic material on top of a substrate. The silicon used is a non-crystalline silicon, as opposed to the solid silicon used in polycrystalline and monocrystalline modules.
A glass layer lays on top to capture sunlight. A semiconductor layer is beneath, between two layers of transparent conduit.
Their thin construction makes them flexible, and thin film panels can typically bend to fit irregular surfaces.
Their unique construction usually puts thin film PV on the higher side of the price spectrum. Unless you need a flexible solar panel — for example, to install on the curved roof of an RV — thin film PV panels’ lower rated power and efficiency, coupled with a higher price relative to electricity production, make them a poor choice.
Even if you do need the flexibility, there are flexible solar panel options that utilize monocrystalline cells and offer 23% efficiency.
What Are the Applications of Solar Cells?
There are countless applications for photovoltaic solar cells.
Without solar cells, there would be no solar panels, and electricity generation using sunlight wouldn’t exist, at least not in the way we’ve grown accustomed to and increasingly reliant on — even for on-grid electricity.
In 2022, 143 billion kilowatt hours (kWh) of on-grid electricity were produced using solar panels. Additionally, the “US Energy Information Administration (EIA) estimates that an additional 58 billion kWh of electricity generation was [produced by] small-scale solar photovoltaic systems in 2022.”
Here are three of the most common ways consumers use solar panels (and the PV cells that make them work).
Rooftop Arrays for Whole-Home Power
All across the country, residential rooftop solar panel arrays are becoming an increasingly common sight.
Off-grid and grid-tied solar power systems have become more affordable as the technology has improved. Many more people use solar-generated electricity to power part (or all) of their homes.
Solutions like EcoFlow’s whole home generator can provide enough electricity to run the average household. If you’re not ready to go full solar, a portable power station like the DELTA 2 Max coupled with 400W portable solar panels can power many of your essential devices and appliances simultaneously. You can run them off solar all the time, but this option is also particularly beneficial during a blackout.
All of EcoFlow’s solar panels — even the flexible ones — use monocrystalline solar cells and proprietary technology to deliver an industry-leading efficiency rate of up to 23%.
Portable Power Stations and Solar Panels
The monocrystalline solar cells in EcoFlow’s portable solar panels work seamlessly to charge portable power stations like EcoFlow’s lightweight and travel-friendly RIVER 2.
The whole RIVER 2 series is perfect for off-grid outdoor adventures, from backpacking to dry camping to extended RV road trips. Just pick the one with enough AC electricity output and storage to meet your electricity consumption needs — and pair it with a portable solar panel with the appropriate rated power wattage.
For example, the RIVER 2 Pro offers 800W of running AC electricity (1600W starting watts with X-Boost). It has a solar input/charging capacity of 220W — making it an ideal fit with the 220W Bifacial Portable Solar Panel.
Solar panels paired with Power Kits are perfect off-grid power solutions for RV and van life, as well as for tiny homes.
With options from 2 kWh to 15 kWh of electricity storage, EcoFlow’s Power Kits are modular and compact — making them ideal for small spaces that need a LOT of electricity. With a massive 4,800W solar input capacity, you can connect up to 12 x 400W rigid solar panels, which offer 23% efficiency using monocrystalline solar cells. Or you can mix and match rigid with portable and flexible solar panels to meet specific installation requirements.
Check out this online calculator to see what a Power Kit can do for you.
Frequently Asked Questions
No, a solar cell is not a battery. It’s a tiny component, typically made of silicon wafers, that generates electricity using the photovoltaic (PV) effect. Up to hundreds of solar cells are interconnected under the surface of solar panels. The number and type of solar cells used determines a solar panel’s efficiency and rated power output. Monocrystalline and polycrystalline solar cells are the most commonly used. Monocrystalline cells have greater efficiency and can generate more electricity using less surface area from available sunlight than poly cells. A solar battery is a required balance of system (BOS) component for off-grid solar power solutions.
Solar cells are typically made from silicon — from a single crystal (monocrystalline) or from multiple crystals fused together (polycrystalline). Solar cells can be made for other materials like cadmium telluride and copper indium gallium selenide, but these are far less common. The materials used and the manufacturing process determine how much rated power wattage a solar cell can generate and how efficiently it turns direct sunlight into electricity.
Solar cells are the essential building blocks of modern solar power technology. Without solar cells using the photovoltaic effect, electricity generation using clean, renewable energy captured from sunlight would not be possible. Or at least not in the way we understand it today.
No matter what type or manufacturer of solar panel you choose, solar cells are what makes them work. Monocrystalline silicon solar cells are the most efficient at generating electricity from available sunlight — and that’s what you’ll find in all of EcoFlow solar panel options.
If you’re considering switching some or all of your electricity needs to solar, check out EcoFlow’s award-winning off-grid solar power solutions today.
No matter what your solar use case is, EcoFlow probably has a solution for you.