 A photovoltaic module is composed of individual PV cells. This crystalline-silicon module has an aluminium frame and glass on the front. In the field of photovoltaics, a photovoltaic module is a packaged interconnected assembly of photovoltaic cells, also known as solar cells. An installation of photovoltaic modules or panels is known as a photovoltaic array. Photovoltaic cells typically require protection from the environment. For cost and practicality reasons a number of cells are connected electrically and packaged in a photovoltaic module, while a collection of these modules that are mechanically fastened together, wired, and designed to be a field-installable unit, usually with a glass covering and a frame and backing made of metal, plastic or fiberglass, are known as a photovoltaic panel or simply solar panel. A photovoltaic installation typically includes an array of photovoltaic modules or panels, an inverter, batteries (for off grid) and interconnection wiring. Image File history File links Broom_icon. ...
solar panel by BP solar at a german autobahn bridge. ...
solar panel by BP solar at a german autobahn bridge. ...
Aluminum redirects here. ...
Photovoltaic tree in Styria, Austria Photovoltaics, or PV for short, is a solar power technology that uses solar cells or solar photovoltaic arrays to convert light from the sun directly into electricity. ...
A solar cell, made from a monocrystalline silicon wafer A solar cell or photovoltaic cell is a device that converts light energy into electrical energy. ...
A photovoltaic module that is composed of individual PV cells. ...
This article is about the material. ...
This article is about metallic materials. ...
For other uses, see Plastic (disambiguation). ...
Bundle of fiberglass Fiberglass (also called fibreglass and glass fibre) is material made from extremely fine fibers of glass. ...
For other uses, see Inverter (logic gate) and Inverter. ...
Symbols representing a single Cell (top) and Battery (bottom), used in circuit diagrams. ...
Theory and construction The majority of modules use water based Crystalline silicon cells or a thin film cell based on cadmium telluride or silicon (see photovoltaic cells for details). General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance dark gray, bluish tinge Atomic mass 28. ...
Cadmium telluride (CdTe) is a crystalline compound formed from cadmium and tellurium with a zinc blende (cubic) crystal structure (space group F43m). ...
A photovoltaic cell is a device that turns light into electric energy. ...
In order to use the cells in practical applications, they must be:
- connected electrically to one another and to the rest of the system
- protected from mechanical damage during manufacture, transport and installation and use (in particular against hail impact, wind and snow loads). This is especially important for water based silicon cells which are brittle.
- protected from moisture, which corrodes metal contacts and interconnects, (and for thin film cells the transparent conductive oxide layer) thus decreasing performance and lifetime.
- electrically insulated including under rainy conditions
- mountable on a substructure
Most modules are rigid, but there are some flexible modules available, based on thin film cells.
Electrical connections are made in series to achieve a desired output voltage and/or in parallel to provide a desired amount of current source capability. Diodes are included to avoid overheating of cells in case of partial shading.
Since cell heating reduces the operating efficiency it is desirable to minimize the heating. Very few modules incorporate any design features to decrease temperature, however installers try to provide good ventilation behind the module,
New designs of module include concentrator modules in which the light is concentrated by an array of lenses or mirrors onto an array of small cells. This allows the use of cells with a very high cost per unit area (such as gallium arsenide) in a cost-competitive way. This article is about the chemical compound. ...
Depending on construction the photovoltaic can cover a range of frequencies of light and can produce electricity from them, but cannot cover the entire solar spectrum. Hence much of incident sunlight energy is wasted when used for solar panels, although they can give far higher efficiencies if illuminated with monochromatic light. Another design concept is to split the light into different wavelength ranges and direct the beams onto different cells tuned to the appropriate wavelength ranges. [1] This is projected to raise efficiency to 50%. Sunlight conversion rates (module efficiencies) can vary from 5-18% in commercial production. Prism splitting light High Resolution Solar Spectrum Sunlight in the broad sense is the total spectrum of the electromagnetic radiation given off by the Sun. ...
Crystalline silicon modules The most common design of modules contains cells made from silicon wafers. The wafers and cells are manufactured separately from the modules, sometimes in different factories and by different companies.
These cells are connected using conductive ribbons into one or more 'strings'. The module consists of a transparent top surface, an encapsulant, the strings of cells, another layer of encapsulant and a rear layer, and a frame around the outer edge. Typically, the top surface is low iron solar glass, the encapsulant is crosslinkable Ethylene-vinyl acetate (EVA), and the rear layer is a Tedlar- PET-Tedlar laminate. [2] [3] [4] [5] Vulcanization is an example of cross-linking. ...
Ethylene-vinyl acetate (also known as EVA or sometimes simply as acetate) is the copolymer of ethylene and vinyl acetate. ...
Polyvinyl fluoride (PVF) or -(CH2CHF)n- is mainly used in flammability-lowering coating of airplane interiors and photovoltaic module backsheets. ...
Polyethylene terephthalate (aka PET, PETE or the obsolete PETP or PET-P) is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination with glass fiber. ...
Glass The front glass must have a high transmission in the wavelengths used by the cells, ie in 350 to 1200 nm range. Tempered, low-iron glass is the material of choice. Starting in 1990, cerium was added to absorb UV light and thus protect the encapsulant from degradation. Today, due to improvements in encapsulant stability, Ce is rarely used.
Typically, 8% of light is reflected by the outer surface of the glass [6] i.e. at the air-glass interface. This reflective loss can be reduced to allow more light to reach the cell and more electrical power to be generated. Antireflective coatings (ref) or texturing the surface will reduce the reflective loss. However in some cases the textured modules collect dust and the increased light transmission through lower reflective loss is outweighed by light lost due to soiling.
The glass also serves the purpose of keeping out water and rigidifying the module, protecting the cells from damage from hail impact and bending and impact during manufacture, transport and installation. It must be stable under long-term exposure to ultraviolet radiation.
Encapsulant The encapsulant serves two main purposes. The first purpose is to mechanically bond the strings of cells to the glass and thus maintain their positions over the life of the module. The second purpose is to provide an optical bridge between the glass and the cells. Otherwise there would be another air-glass interface and an air silicon interface each causing >=8% loss. The material must, like the glass, have excellent light transmission and be durable enough to last at least 20 years without degrading or debonding from the glass or the silicon. The material of choice is crosslinkable EVA, although Polyvinyl butyral (PVB) is used in modules with a glass backsheet. Polyvinyl butyral (or PVB) is a resin usually used for applications that require strong binding, optical clarity, adhesion to many surfaces, toughness and flexibility. ...
Backsheet The material on the back side of the module provides protection from UV degradation, electrical resistance, and moisture penetration. The majority of modules use a Tedlar-PET-Tedlar sheet. Glass and coated PET are also used.
Process The encapsulant is melted and crosslinked in a vacuum laminator (except for glass front-glass back modules which are made in an autoclave. The glass, strings and backsheet are now attached to one another and form a 'laminate'. A frame made of aluminium profile is fitted around the edges of the laminate with an elastomeric seal (e.g. silicone) to seal the edges against moisture. The frame provides rigidity and the means to attach the module to a supporting structure. Finally, the strings are electrically terminated into a junction box usually glued to the back of the module. A junction box, at least in electrical terms, is a container for electrical junctions, usually intended to conceal them from sight, and to some extent tampering. ...
Crystalline silicon modules have an efficiency of 13-18%.
 1. Cells connected to make string |
 2. encapsulant film ready |
3. ready for lamination. Note ribbons terminating 2 strings | | |
 5. Aluminium profiles added to make the frame | Image File history File links Size of this preview: 800 × 600 pixelsFull resolution (1024 × 768 pixel, file size: 358 KB, MIME type: image/jpeg) Description: Photovoltaic cells, aligned and ribboned on the back. ...
Image File history File links Size of this preview: 800 × 600 pixelsFull resolution (1024 × 768 pixel, file size: 358 KB, MIME type: image/jpeg) Description: Photovoltaic cells, aligned and ribboned on the back. ...
Image File history File linksMetadata Size of this preview: 800 × 600 pixelsFull resolution (1024 × 768 pixel, file size: 446 KB, MIME type: image/jpeg) Description: Photovoltaic cells already fixed to their back tedlar foil. ...
Image File history File linksMetadata Size of this preview: 800 × 600 pixelsFull resolution (1024 × 768 pixel, file size: 446 KB, MIME type: image/jpeg) Description: Photovoltaic cells already fixed to their back tedlar foil. ...
Image File history File links Size of this preview: 800 × 600 pixelsFull resolution (1024 × 768 pixel, file size: 424 KB, MIME type: image/jpeg) Description: Photovoltaic modules backside, with all ribbon terminations exposed, ready for the tedlar back support foil. ...
Image File history File links Size of this preview: 800 × 600 pixelsFull resolution (1024 × 768 pixel, file size: 424 KB, MIME type: image/jpeg) Description: Photovoltaic modules backside, with all ribbon terminations exposed, ready for the tedlar back support foil. ...
Image File history File links Size of this preview: 800 × 600 pixelsFull resolution (1024 × 768 pixel, file size: 347 KB, MIME type: image/jpeg) Description: Photovoltaic module entering the oven, where EVA will melt and glue together the front glass and the solar cells. ...
Image File history File links Size of this preview: 800 × 600 pixelsFull resolution (1024 × 768 pixel, file size: 347 KB, MIME type: image/jpeg) Description: Photovoltaic module entering the oven, where EVA will melt and glue together the front glass and the solar cells. ...
Image File history File links Size of this preview: 800 × 600 pixelsFull resolution (1024 × 768 pixel, file size: 458 KB, MIME type: image/jpeg) Description: Anodyzed aluminium frame being attached to a photovoltaic module. ...
Image File history File links Size of this preview: 800 × 600 pixelsFull resolution (1024 × 768 pixel, file size: 458 KB, MIME type: image/jpeg) Description: Anodyzed aluminium frame being attached to a photovoltaic module. ...
Rigid thin-film modules In rigid thin film modules, the cell and the module are manufactured in the same production line.
The cell is created directly on a glass substrate or superstrate, and the electrical connections are created in situ, a so called "monolithic integration". The substrate or superstrate is laminated with an encapsulant to a front or back sheet, usually another sheet of glass.
The main cell technologies in this category are CdTe, amorphous silicon, micromorphous silicon (alone or tandem), or CIGS (or variant). Amorphous silicon has a sunlight conversion rate of 5-9%. Cadmium telluride (CdTe) is a crystalline compound formed from cadmium and tellurium with a zinc blende (cubic) crystal structure (space group F43m). ...
Amorphous silicon (a-Si) is the non-crystalline allotropic form of silicon. ...
Copper indium gallium selenide (CIGS) is a new semiconductor material comprising copper, indium, gallium, and selenium, CuInGaSe2. ...
Flexible thin-film modules Flexible thin film cells and modules are manufactured in the same production line. They are created by depositing the photoactive layer and other necessary layers on a flexible substrate. If the substrate is an insulator (e.g. polyester or polyimide film) then monolithic integration can be used. If a conductor then monolithic integration cannot be used, and another technique for electrical connection used. The cells are converted to a module by lamination to a transparent colourless fluoropolymer on the front side (typically ETFE or FEP) and a polymer suitable for bonding to the final substrate on the other side. The only commercially available (in MW quantities) in a flexible module is amorphous silicon triple junction (from Unisolar). ETFE (Ethylene TetrafluoroEthylene) - a fluorocarbon-based polymer (a fluoropolymer), a kind of plastic. ...
Teflon is polytetrafluoroethylene (PTFE), a polymer of fluorinated ethylene. ...
References - ^ http://www.arpa.mil/sto/smallunitops/vhesc.html
- ^ http://www1.eere.energy.gov/solar/fp_modules.html DOE-EERE website module description
- ^ http://www.re.sandia.gov/en/pb/ar/quarterly.pdf Sandia labs module description
- ^ http://www.mtpc.org/cleanenergy/solar/panelconstruct.htm Massachussetts Technology Collaborative page of PV module construction
- ^ http://www.solarserver.de/wissen/photovoltaik-e.html Solarserver. de page on module construction
- ^ http://www.funktionale-oberflaechen.de/english/a1_ent_f.html#a1 Fraunhofer Inst 1 pager on AR
See also Image File history File links Portal. ...
Photovoltaic tree in Styria, Austria Photovoltaics, or PV for short, is a solar power technology that uses solar cells or solar photovoltaic arrays to convert light from the sun directly into electricity. ...
A photovoltaic module that is composed of individual PV cells. ...
A photovoltaic cell is a device that turns light into electric energy. ...
The CIS Tower, Manchester, England, was clad in PV panels at a cost of £5. ...
This is a List of photovoltaics companies, who manufacture and/or supply solar cells and/or photovoltaic modules. ...
External links - Filling up at the plug
- Illustration of manufacturing process of crystalline silicon modules at DuPont website
- Video of cSi module manufacture process at the Spire corp website
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