Solar Cells - How they work
Learn about solar cells and how they work. Photovoltaic technology makes use of the abundant energy in the sun, and it has little impact on our environment. Photovoltaics can be used in a wide range of products, from small consumer items to large commercial solar electric systems.
Have
you ever wondered how electricity is produced by
a solar system? To help you understand we will
cover the basics of PV technology, which
includes the science (underlying physics), how
various solar or PV devices are designed and are
utilized in a complete and functioning power
system.
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Photovoltaic Devices
Photovoltaic devices can be made from various types of semiconductor materials, deposited or arranged in various structures, to produce solar cells that have optimal performance. In this section, we first review the three main types of materials used for solar cells. The first type is silicon, which can be used in various forms, including single-crystalline, multicrystalline, and amorphous. The second type is polycrystalline thin films, with specific discussion of copper indium diselenide (CIS) cadmium telluride (CdTe), and thin-film silicon. Finally, the third type of material is single-crystalline thin film, focusing especially on cells made with gallium arsenide
Solar Cell Materials
- Polycrystalline
- Silicon
- Single-Crystalline
Solar Cell Structures
- Homojunction
- Hetrojunction
- p-i-n/n-i-p
- Multijunction
The Physics of Photovoltaics
What is meant by
photovoltaics? First used in about
1890, the word has two
parts: photo, derived from the
Greek word for light, and volt,
relating to electricity pioneer Alessandro
Volta. So, photovoltaics could
literally be translated as
light-electricity. And that's what
photovoltaic (PV) materials and devices do —
they convert light energy into electrical
energy or the Photoelectric Effect, as
French physicist Edmond Becquerel discovered
as early as 1839.
Commonly known as solar cells, individual PV cells are electricity-producing devices made of semiconductor materials. PV cells come in many sizes and shapes from smaller than a postage stamp to several inches across. They are often connected together to form PV modules that may be up to several feet long and a few feet wide. Typically, Solar Modules are made up of 36 or 72 Solar Cells connected together to form a complete Module, in turn, the module can be combined and connected to other modules to form a PV array (several modules) to power a load.
The size of a solar array depends on several factors, such as the amount of sunlight available in a particular location and the needs of the consumer. The modules of the array make up the core component of a PV system, which can also include electrical connections, mounting hardware, power-conditioning equipment, distribution and batteries that store solar energy for use when the sun isn't shining.
parts: photo, derived from the
Greek word for light, and volt,
relating to electricity pioneer Alessandro
Volta. So, photovoltaics could
literally be translated as
light-electricity. And that's what
photovoltaic (PV) materials and devices do —
they convert light energy into electrical
energy or the Photoelectric Effect, as
French physicist Edmond Becquerel discovered
as early as 1839.Commonly known as solar cells, individual PV cells are electricity-producing devices made of semiconductor materials. PV cells come in many sizes and shapes from smaller than a postage stamp to several inches across. They are often connected together to form PV modules that may be up to several feet long and a few feet wide. Typically, Solar Modules are made up of 36 or 72 Solar Cells connected together to form a complete Module, in turn, the module can be combined and connected to other modules to form a PV array (several modules) to power a load.
The size of a solar array depends on several factors, such as the amount of sunlight available in a particular location and the needs of the consumer. The modules of the array make up the core component of a PV system, which can also include electrical connections, mounting hardware, power-conditioning equipment, distribution and batteries that store solar energy for use when the sun isn't shining.
PV Systems
A photovoltaic (PV) or solar cell is the basic building block of a PV (or solar electric) system. An individual PV cell is usually quite small, typically producing about 1 or 2 watts of power. To boost the power output of PV cells, we connect them together to form larger units called modules. Modules, in turn, can be connected to form even larger units called arrays, which can be interconnected to produce more power, and so on. In this way, we can build PV systems able to meet almost any electric power need, whether small or large.The most common PV system for off-grid homes are the flat-plate systems. By themselves, modules or arrays do not represent an entire PV system. We also need structures to put them on that point them toward the sun, and components that take the direct-current electricity produced by modules and "condition" that electricity, usually by converting it to alternate-current electricity. We might also want to store some electricity, usually in batteries, for later use. All these items are referred to as the "balance of system" (BOS) components.
Combining modules with the Balance of System components creates an entire PV system. This system is usually everything we need to meet a particular energy demand, such as powering a water pump, or the appliances and lights in a home, or, if the PV system is large enough, all the electrical requirements of a whole community
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