太阳能电池中英文

2021年1月25日发(作者：aiee)
Photovoltaics (PV) is a method of generating electrical power by converting solar radiation into
direct current electricity using semiconductors that exhibit the photovoltaic effect. Photovoltaic
power generation employs solar panels composed of a number of solar cells containing a
photovoltaic material. Materials presently used for photovoltaics include monocrystalline silicon,
polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium gallium
selenide/sulfide. Due to the growing demand for renewable energy sources, the manufacturing of
solar cells and photovoltaic arrays has advanced considerably in recent years. Solar photovoltaics
is growing rapidly, albeit from a small base, to a total global capacity of 67,400 megawatts (MW)
at the end of 2011, representing 0.5% of worldwide electricity total power output of
the world’s PV capacity run over a calendar year is equal to some 80 billion kWh of electricity.
This is sufficient to cover the annual power supply needs of over 20 million households in the
world. More than 100 countries use solar PV. Installations may be ground-mounted (and
sometimes integrated with farming and grazing) or built into the roof or walls of a building
(building-integrated photovoltaics). Driven by advances in technology and increases in
manufacturing scale and sophistication, the cost of photovoltaics has declined steadily since the
first solar cells were manufactured and the levelised cost of electricity (LCOE) from PV is
competitive with conventional electricity sources in an expanding list of geographic
metering and financial incentives, such as preferential feed-in tariffs for solar-generated electricity,
have supported solar PV installations in many current technology, photovoltaics
recoup the energy needed to manufacture them in 1 to 4 years.[ Solar cells Photovoltaics are best
known as a method for generating electric power by using solar cells to convert energy from the
sun into a flow of electrons. The photovoltaic effect refers to photons of light exciting electrons
into a higher state of energy, allowing them to act as charge carriers for an electric current. The
photovoltaic effect was first observed by Alexandre-Edmond Becquerel in term
photovoltaic denotes the unbiased operating mode of a photodiode in which current through the
device is entirely due to the transduced light energy. Virtually all photovoltaic devices are some
type of photodiode. Solar cells produce direct current electricity from sun light, which can be used
to power equipment or to recharge a battery. The first practical application of photovoltaics was to
power orbiting satellites and other spacecraft, but today the majority of photovoltaic modules are
used for grid connected power generation. In this case an inverter is required to convert the DC to
AC. There is a smaller market for off-grid power for remote dwellings, boats, recreational vehicles,
electric cars, roadside emergency telephones, remote sensing, and cathodic protection of pipelines.
Photovoltaic power generation employs solar panels composed of a number of solar cells
containing a photovoltaic material. Materials presently used for photovoltaics include
monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper
indium gallium selenide/sulfide.[1] Due to the growing demand for renewable energy sources, the
manufacturing of solar cells and photovoltaic arrays has advanced considerably in recent
years.[2][3][4] Cells require protection from the environment and are usually packaged tightly
behind a glass sheet. When more power is required than a single cell can deliver, cells are
electrically connected together to form photovoltaic modules, or solar panels. A single module is
enough to power an emergency telephone, but for a house or a power plant the modules must be
arranged in multiples as arrays. A significant market has emerged in off-grid locations for solar-
power- charged storage-battery based solutions. These often provide the only electricity
available.[15] The first commercial installation of this kind was in 1966 on Ogami Island in Japan
to transition Ogami Lighthouse from gas torch to fully self-sufficient electrical power. Due to the
growing demand for renewable energy sources, the manufacture of solar cells and photovoltaic
arrays has advanced dramatically in recent years.[2][3][4] Solar photovoltaics is growing rapidly,
albeit from a small base, to a total global capacity of 67,400 megawatts (MW) at the end of 2011,
representing 0.5%
of worldwide electricity demand.[5] The total power output of the world’s PV
capacity run over a calendar year is equal to some 80 billion kWh of electricity. This is sufficient
to cover the annual power supply needs of over 20 million households in the world.[5] More than
100 countries use solar PV.[6] World solar PV capacity (grid-connected) was 7.6 GW in 2007, 16
GW in 2008, 23 GW in 2009, and 40 GW in 2010.[16][17][18] More than 100 countries use solar
PV.[6] Installations may be ground- mounted (and sometimes integrated with farming and
grazing)[7] or built into the roof or walls of a building (building-integrated photovoltaics).
Photovoltaic power capacity is measured as maximum power output under standardized test
conditions (STC) in
may be less than or greater than this standardized, or
location, time of day, weather conditions, and other factors.[20] Solar photovoltaic array capacity
factors are typically under 25%, which is lower than many other industrial sources of
electricity.[21] The EPIA/Greenpeace Advanced Scenario shows that by the year 2030, PV
systems could be generating approximately 1.8 TW of electricity around the world. This means
that, assuming a serious commitment is made to energy efficiency, enough solar power would be
produced globally in twenty-
five years’ time to satisfy the electricity needs of almost 14% of the
world’s population.[22] Current developments Photovol
taic panels based on crystalline silicon
modules are encountering competition in the market by panels that employ thin-film solar cells
(CdTe[23] CIGS,[24] amorphous Si,[25] microcrystalline Si), which had been rapidly evolving
and are expected to account for 31 percent of the global installed power by 2013.[26] However,
precipitous drops in prices for polysilicon and their panels in late 2011 have caused some thin-film
makers to exit the market and others to experience severely squeezed profits.[27] Other
developments include casting wafers instead of sawing,[28] concentrator modules, 'Sliver' cells,
and continuous printing processes. The San Jose-based company Sunpower produces cells that
have an energy conversion ratio of 19.5%, well above the market average of 12
–
18%.[29] The
most efficient solar cell so far is a multi-junction concentrator solar cell with an efficiency of
43.5%[30] produced by the National Renewable Energy Laboratory in April 2011. The highest
efficiencies achieved without concentration include Sharp Corporation at 35.8% using a
proprietary triple-junction manufacturing technology in 2009,[31] and Boeing Spectrolab (40.7%
also using a triple-layer design). A March 2010 experimental demonstration of a design by a
Caltech group led by Harry Atwater which has an absorption efficiency of 85% in sunlight and
95% at certain wavelengths is claimed to have near perfect quantum efficiency.[32] However,
absorption efficiency should not be confused with the sunlight-to-electricity conversion efficiency.
For best performance, terrestrial PV systems aim to maximize the time they face the sun. Solar
trackers achieve this by moving PV panels to follow the sun. The increase can be by as much as
20% in winter and by as much as 50% in summer. Static mounted systems can be optimized by
analysis of the sun path. Panels are often set to latitude tilt, an angle equal to the latitude, but
performance can be improved by adjusting the angle for summer or winter. Generally, as with
other semiconductor devices, temperatures above room temperature reduce the performance of
photovoltaics.[33] A number of solar panels may also be mounted vertically above each other in a
tower, if the zenith distance of the Sun is greater than zero, and the tower can be turned
horizontically as a whole and each panels additionally around a horizontical axis. In such a tower
the panels can follow exactly the Sun. Such a device may be described as a ladder mounted on a
turnable disk. Each step of that ladder is the middle axis of a rectangular solar panel. In case the
zenith distance of the Sun gets zero, the ―ladder‖ may be rotated to the north or the south to avoid
that a solar panel produces a shadow on a lower mounted solar panel. Instead of an exactly vertical
tower one can choose a tower with an axis directed to the polar star, meaning that it is parallel to
the rotation axis of the Earth. In this case the angle between the axis and the Sun is always larger
than 66 degrees. During a day it is only necessary to turn the panels around this axis to follow the
Sun. The 2011 European Photovoltaic Industry Association (EPIA) report predicted that,
future of the PV market remains bright in the EU and the rest of the world,

creating new opportunities for a competitive, safe and reliable electricity source such as PV.
2012 could see the installation of 20
–
30 GW of PV
—
about the same as in 2011. Unfortunately,
the industry's capacity continues to expand, to perhaps as much as 38 GW. The resulting glut of
supply has crushed prices and profits.[35] By 2015, 131
–
196 GW of photovoltaic systems could
be installed around the globe.[34] Economics The output of a photovoltaic array is a product of
the area, the efficiency, and the insolation. The capacity factor, or duty cycle, of photovoltaics is
relatively low, typically from 0.10 to 0.30, as insolation ranges, by latitude and prevailing weather,
and is location specific from about 2.5 to 7.5 sun hours/day. Panels are rated under standard
conditions by their output power. The DC output is a product of the rated output times the number
of panels times the insolation times the number of days. The sunlight received by the array is
affected by a combination of tilt, tracking and shading. Tracking increases the yield but also the
cost, both installation and maintenance. A dual axis tracker can increase the effective insolation by
roughly 35-40%, while temperature effects can around the globe. Utility- scale solar power can
now be delivered in California at prices well below $$100/MWh ($$0.10/kWh) less than most other