Are Solar Cells Different From Solar Panels?

Solar cells and solar panels are both important parts of solar power generation, but they serve different roles. Solar cells are the individual units that convert sunlight into electricity. Solar panels, also known as photovoltaic (PV) panels, are made up of many solar cells wired together in a group. The solar cells within a solar panel absorb sunlight and convert it into direct current (DC) electricity.

While solar cells and solar panels work together to produce solar power, they have distinct differences that set them apart. This article will examine solar cells and solar panels in detail, comparing and contrasting their workings, types, applications and more.

Table of Contents

Definition of Solar Cells

Solar cells are devices that convert sunlight directly into electricity. They are sometimes referred to as photovoltaic cells because they use the photovoltaic effect to absorb photons from sunlight and release electrons, generating electric current. At its most basic, a solar cell is made of semiconducting materials similar to those used in computer chips. When sunlight hits these materials, the photons of light knock electrons loose, allowing them to flow freely and produce electricity.

The most common solar cells are made from silicon, which can be combined with other elements like boron and phosphorus to form the p-n junction capable of producing electricity. Thin strips of silicon act as photoactive material inside the cell. When light penetrates the cell, electricity is generated. Solar cells are often linked together to form solar photovoltaic modules or panels.

How Solar Cells Work

Solar cells work through the photovoltaic effect, which describes how matter converts sunlight into electricity. When sunlight hits the solar cell, photons from the sunlight knock electrons free from the atoms in the cell’s semiconductor material. The photons carry energy that give the electrons enough kinetic energy to break free. The electrons are forced to flow in a certain direction within the cell, creating an electric current that we can then harness for power.

The photovoltaic effect occurs in solar cells made of semiconductors such as crystalline silicon. When sunlight hits the cell, electrons are knocked loose from their atoms. The electrons flow from one side of the cell to the other, generating an electrical current. This electricity is captured and utilized through electrical contacts on the surface of the cell.

The knocking loose of electrons is possible because of the atomic structure of semiconductors. They have a unique ability to absorb photons of light and transfer the energy to electrons. When enough sunlight hits the cells, they can produce electricity at a usable voltage and deliver power to be used or stored in batteries.

Types of Solar Cells

There are three main types of solar cells:

Crystalline Silicon Solar Cells

Crystalline silicon solar cells are the most common type of solar cells used in solar panels today. They are made from silicon wafers that act as semiconductors. Crystalline silicon cells come in two main types:

Monocrystalline silicon – Made from a single continuous crystal of silicon, making them the most efficient but also most expensive.
Polycrystalline silicon – Made from multiple silicon crystal grains fused together, making them slightly less efficient but cheaper.

Thin-Film Solar Cells

Thin-film solar cells are made by depositing thin layers of photosensitive materials onto substrates like glass, plastic or metal. Thin-film cells tend to have lower efficiencies than crystalline silicon cells but can be cheaper to manufacture. Types of thin-film cells include:

Cadmium telluride (CdTe)
Copper indium gallium selenide (CIGS)
Amorphous silicon (a-Si)

Emerging and Novel Solar Cells

Some novel solar cell technologies that are still emerging or in early stages of commercialization include:

Perovskite solar cells
Organic photovoltaic (OPV) cells

Dye-sensitized solar cells (DSSC)
Quantum dot solar cells

These new solar cell technologies aim to improve efficiency, reduce costs, or provide more flexibility compared to traditional silicon solar cells.

Definition of Solar Panels

Solar panels are collections of solar cells wired together in a frame. They contain photocells, which are the solar cells that convert sunlight into electricity. The solar cells are arranged into larger units called modules, which are then assembled together into the overall solar panel.

The individual solar cells within a solar panel are usually made from silicon and generate a specific amount of electricity. When these cells are wired together into a solar panel, their power output combines to deliver higher overall electricity production. This modular setup allows solar panels to be configured in different sizes and power outputs depending on the application and space available.

Solar panel sizes are measured in watts, such as 250W or 330W. The number of individual solar cells within a panel, along with the efficiency of the photocells, determine the panel’s wattage rating and power capacity. Overall, a solar panel’s main purpose is to absorb and convert sunlight into usable electricity through these interconnected solar cells.

Components of Solar Panels

Solar panels are composed of a few different main components that work together to absorb sunlight and convert it into usable electricity:

Solar Cells – The solar cells are small semiconductor wafers, usually made of silicon, that directly convert sunlight into electricity through the photovoltaic effect. They are the core component that makes solar panels work.
Glass Casing – The solar cells are sandwiched between a transparent top layer of glass or plastic and a backing layer to protect them from the environment. The glass casing allows sunlight to pass through to the solar cells below.

Aluminum Frame – Solar panels are framed with aluminum framing around the edges to provide structural support and allow for easy mounting and installation.
Junction Box – The junction box on the back of the solar panel contains electrical connections and wiring to transfer the generated current off the rooftop and into the electrical system.

By assembling together layers of glass, framing, wiring, and most importantly the solar cell wafers, the solar panel can efficiently collect and convert sunlight into useful electricity for homes and businesses.

Types of Solar Panels

There are three main types of solar panels used in photovoltaic systems today:

Monocrystalline Solar Panels

Monocrystalline solar panels are made from silicon ingots, which are cylindricalblocks formed by pouring molten silicon into a mold. These ingots are then sliced into thin wafers to make the solar cells. Monocrystalline solar cells have a distinctive look with perfectly straight lines and a uniform coloring. These panels have the highest efficiency rates since the silicon molecules are aligned in a continuous crystal lattice structure with few defects. However, they are also the most expensive due to the complex manufacturing process.

Polycrystalline Solar Panels

Polycrystalline solar panels are made from silicon ingots like monocrystalline, but these ingots are cooled and solidified less carefully and have a more disjointed molecular structure. The silicon atoms are arranged in a fractured pattern, which reduces efficiency somewhat but also lowers production costs. Polycrystalline solar panels have a speckled blue color and square-shaped cells due to the random crystal formations.

Thin-Film Solar Panels

Thin-film solar panels are made by depositing one or more thin layers of photovoltaic material onto a substrate like glass, plastic or metal. Thin-film panels use little semiconductor material compared to crystalline silicon cells, reducing costs. The most common thin-film materials are cadmium telluride (CdTe), copper indium gallium selenide (CIGS) and amorphous silicon (a-Si). Thin-film panels have lower efficiency rates, but their flexibility makes them useful for applications that can’t support rigid panels.

Comparing Solar Cells and Panels

Solar cells and solar panels may seem similar at first glance, but they are distinct technologies that play different roles in generating solar power. The key differences between solar cells and panels are:

Solar cells are the core technology that converts sunlight into electricity. They are photovoltaic devices made up of semiconducting materials that produce an electric current when exposed to sunlight. The most common material used in solar cells is silicon. When sunlight hits the solar cell, the photons excite electrons in the silicon, causing electricity to flow. A single solar cell produces a small amount of electric current and voltage.

Solar panels are collections of many solar cells wired together. The individual solar cells in a panel are connected to form a circuit and the currents and voltages from each cell add together. This allows solar panels to produce higher voltages and currents than individual solar cells. Solar panels also contain additional components like metal frames, wiring, and inverters to convert the electricity from DC to AC. The size of a solar panel can vary greatly, from small portable versions to large utility-scale arrays.

So in summary, solar cells are the photovoltaic component that generates electricity, while solar panels wire together many solar cells to produce power at a higher scale. Solar cells are the core technology, while panels integrate and connect cells for practical application.

Applications

Solar cells and solar panels are used for different applications due to their design and function.

Solar cells are most commonly used for small electronics like calculators, watches, and toys. Their small size allows them to power these portable devices directly. Solar cells can also be used on satellites and spacecraft to generate electricity from sunlight in space.

In contrast, solar panels are assembled from multiple solar cells and used in larger applications like powering homes, businesses, and the electrical grid. Solar panels can be mounted on rooftops or ground-installed to generate renewable electricity. Their modularity allows solar panels to be wired together into large arrays that can power anything from a tiny home to a large commercial building.

So in summary, tiny solar cells power small electronics while large arrays of solar panels power homes, businesses, and even feed electricity back into the utility grid. The scalability of photovoltaic technology allows it to be used in devices of all sizes.

Conclusion

In summary, solar cells and solar panels are related but distinct technologies. Solar cells are the individual units that convert sunlight into electricity through the photovoltaic effect. Many solar cells together make up a solar panel or module. The solar cells in a panel are connected together to generate usable voltages and power outputs. While solar panels contain solar cells, the overall product has additional components like protective glass shields and aluminum frames to enable installation. Both solar cells and solar panels are important parts of photovoltaic solar energy systems, with solar cells representing the core technology and solar panels the end product designed for practical applications.

Though solar cells and panels work hand-in-hand, they play different roles. Solar cells convert light, while solar panels have the supporting structure to interface with real-world systems. Understanding the difference allows for clearer discussions around photovoltaic technologies and how they are applied. Whether designing solar systems or just learning about how they operate, the unique functions and relationships between solar cells and panels are key to grasp.