Solar battery

In 1839, Alexander Edmond Becquerel discovered the effect of converting light into electricity. Charles Fritts began using selenium to turn light into electricity. The first prototypes of solar panels were created by the Italian photochemist Giacomo Luigi Chamican .

April 25, 1954, experts at Bell Laboratories announced the creation of the first silicon-based solar panels to produce electric current. This discovery was made by three employees of the company - Calvin Souther Fuller (Calvin Souther Fuller), Daryl Chapin (Daryl Chapin) and Gerald Pearson (Gerald Pearson). Already after 4 years, March 17, 1958, the satellite with the use of solar panels, the Avangard-1 , was launched in the United States. On May 15, 1958, the satellite with the use of solar batteries, Sputnik-3 , was also launched in the USSR.

Portable Electronics

To provide electricity and / or recharge batteries of various consumer electronics - calculators, players, flashlights, etc.

Electric cars

For recharging electric vehicles .

Aviation

One of the projects for creating an aircraft using exclusively solar energy is Solar Impulse .

Energy for buildings

Large-sized solar panels, like solar collectors, are widely used in tropical and subtropical regions with a large number of sunny days. Especially popular in the Mediterranean countries, where they are placed on the roofs of houses.

Since March 2007, new houses in Spain have been equipped with solar water heaters to independently provide from 30% to 70% of the demand for hot water, depending on the location of the house and the expected water consumption. Non-residential buildings (shopping centers, hospitals, etc.) must have photovoltaic equipment ^[1] .

Currently, the switch to solar panels is causing a lot of criticism among people. This is due to higher electricity prices, clutter of the natural landscape. Opponents of the transition to solar panels criticize such a transition, since owners of houses and land on which solar panels and wind power plants are installed receive subsidies from the state, but ordinary tenants do not. In this regard, the German Federal Ministry of Economics has developed a bill that will allow in the near future to introduce incentives for tenants living in houses that are provided with energy from photovoltaic installations or block thermal power plants. Along with the payment of subsidies to homeowners who use alternative energy sources, it is planned to pay subsidies to tenants living in these houses. ^[2]

Energy supply of settlements

Pavement

Solar panels as a road surface :

• In 2014, the first solar-powered bicycle track in the world opened in the Netherlands.
• In 2016, French Minister of Ecology and Energy Segolene Royal announced plans to build 1,000 km of roads with built-in shock and heat-resistant solar panels. It is assumed that 1 km of such a road will be able to provide the electric power needs of 5,000 people (excluding heating) ^[3] .
• In February 2017, a solar-powered road was opened by the French government in the Norman village of Tourouvre-au-Perche. A kilometer-long section of the road is equipped with 2880 solar panels. Such a pavement will provide electricity to the streetlights of the village. The panels will generate 280 megawatts of electricity each year. The construction of a section of the road cost 5 million euros. ^[four]

Space Use

Solar batteries are one of the main ways of generating electric energy on spacecraft : they work for a long time without the consumption of any materials, and at the same time they are environmentally friendly, unlike nuclear and radioisotope energy sources.

However, when flying at a great distance from the Sun (beyond the orbit of Mars ), their use becomes problematic, since the flow of solar energy is inversely proportional to the square of the distance from the Sun. When flying to Venus and Mercury , on the contrary, the power of solar panels increases significantly (in the Venus region by 2 times, in the region of Mercury by 6 times).

Medical Use

South Korean scientists have developed a subcutaneous solar cell. A miniature energy source can be implanted under the skin of a person in order to ensure uninterrupted operation of devices implanted in the body, for example, a pacemaker. Such a battery is 15 times thinner than a hair and can be charged even if sunscreen is applied to the skin ^[5] .

The power of the solar radiation flux at the entrance to the Earth’s atmosphere (AM0) is about 1366 watts ^[6] per square meter (see also AM1, AM1.5, AM1.5G, AM1.5D ^{[7] [8]} ). At the same time, the specific power of solar radiation in Europe in very cloudy weather even during the day ^{[9] may} be less than 100 W / m² . With the help of common industrially produced solar cells, it is possible to convert this energy into electricity with an efficiency of 9-24% . At the same time, the battery price will be about 1-3 US dollars per watt of rated power. For industrial electricity generation using photocells, the price per kWh will be $ 0.25. According to the European Photovoltaic Association (EPIA), by 2020 the cost of electricity generated by “solar” systems will drop to less than 0.10 € per kW · h for industrial installations and less than 0.15 € per kWh for installations in residential buildings ^[10] .

Solar cells and modules are divided according to type and are: single-crystal, poly-crystalline, amorphous (flexible, film). ^[eleven]

In 2009, Spectrolab (a subsidiary of Boeing) demonstrated a solar cell with an efficiency of 41.6% ^[12] . In January 2011, it was expected that this company would enter the market for solar cells with an efficiency of 39% ^[13] . In 2011, the California-based Solar Junction company achieved a 5.5 × 5.5 mm photocell efficiency of 43.5%, which is 1.2% higher than the previous record ^[14] .

In 2012, Morgan Solar created the Sun Simba system of polymethyl methacrylate (Plexiglas), germanium and gallium arsenide, combining the hub with the panel on which the photocell is mounted. The efficiency of the system with the panel stationary is 26-30% (depending on the time of the year and the angle at which the Sun is located), twice exceeding the practical efficiency of solar cells based on crystalline silicon ^[15] .

In 2013, Sharp created a 4 × 4 mm three-layer photocell on an indium gallium arsenide basis with 44.4% efficiency ^[16] , and a team of specialists from the Fraunhofer Institute for Solar Energy Systems, Soitec, CEA-Leti and the Berlin Center Helmholtz created a photocell using a Fresnel lens with an efficiency of 44.7%, surpassing its own achievement in 43.6% ^[17] . In 2014, the Fraunhofer Institute of Solar Energy Systems created solar panels in which, thanks to the focusing of the light on a very small photocell, the efficiency was 46% ^{[18] [19]} .

In 2014, Spanish scientists developed a silicon photovoltaic cell capable of converting solar infrared radiation into electricity ^[20] .

A promising direction is the creation of photocells based on nanoantennas , operating on direct rectification of currents induced in a small antenna (of the order of 200-300 nm) by light (that is, electromagnetic radiation of a frequency of the order of 500 THz). Nanoantennas do not require expensive raw materials for production and have a potential efficiency of up to 85% ^{[21] [22]} .

Also, in 2018, with the discovery of the flexophotovoltaic effect, the possibility of increasing the efficiency of photocells was discovered ^[23] ., And also due to the extension of the life of hot carriers (electrons), the theoretical limit of their efficiency rose from 34 to 66 percent immediately ^[24] .

In 2019, Russian scientists from the Skolkovo Institute of Science and Technology (Skoltech) , Institute of Inorganic Chemistry named after A.V. Nikolaev of the Siberian Branch of the Russian Academy of Sciences (SB RAS) and the Institute of Problems of Chemical Physics RAS received a fundamentally new semiconductor material for solar cells, devoid of most of the shortcomings of materials used today ^[25] . A group of Russian researchers published in the journal Journal of Materials Chemistry A ^{[26] the} results of work on the application of a new semiconductor material developed by them for solar cells — complex polymer bismuth iodide ({[Bi ₃ I ₁₀ ]} and {[BiI ₄ ]}), structurally similar to the mineral perovxite (natural calcium titanate), which showed a record conversion rate of light into electricity. ^{[26] [27]} The same group of scientists created a second analogous semiconductor based on complex antimony bromide with a perovxite-like structure. ^{[28] [29]}

The structural features of solar cells cause a decrease in the performance of panels with increasing temperature.

Partial dimming of the panel causes a drop in the output voltage due to losses in the unlit element, which begins to act as a parasitic load. This drawback can be eliminated by installing a bypass on each photocell of the panel. In cloudy weather, in the absence of direct sunlight, panels that use lenses to concentrate radiation become extremely inefficient, since the lens effect disappears.

From the operating characteristics of the photovoltaic panel, it can be seen that in order to achieve maximum efficiency, the correct selection of load resistance is required. For this, photovoltaic panels are not directly connected to the load, but rather they use a controller for controlling photovoltaic systems, which ensures optimal operation of panels.

• The need to use large areas;
• The solar power plant does not work at night and does not work well enough in the evening twilight, while the peak of power consumption occurs precisely in the evening hours;
• Despite the environmental cleanliness of the energy received, the photocells themselves contain toxic substances, such as lead , cadmium , gallium , arsenic , etc. ^[31]

Solar power plants are criticized because of the high costs, as well as the low stability of complex lead halides and the toxicity of these compounds. Lead-free semiconductors for solar cells, for example, based on bismuth ^[26] and antimony, are currently under active development.

Due to its low efficiency, which reaches 20 percent at best, solar panels become very hot. The remaining 80 percent of solar energy heats solar panels to an average temperature of around 55 ° C. With an increase in the temperature of the photovoltaic cell by 1 °, its efficiency decreases by 0.5%. This dependence is nonlinear and an increase in the temperature of the element by 10 ° leads to a decrease in efficiency by almost a factor of two. Active elements of cooling systems (fans or pumps) that transfer refrigerant consume a significant amount of energy, require periodic maintenance and reduce the reliability of the entire system. Passive cooling systems have very low performance and can not cope with the task of cooling solar panels ^[32] .

Very often, single photocells do not produce enough power. Therefore, a certain number of photocells are connected into the so-called photoelectric solar modules and a reinforcement is mounted between the glass plates. This assembly can be fully automated ^[33] .

The five largest manufacturers

Largest manufacturers of photovoltaic cells (in terms of total capacity) in 2016. ^[34]

2. Trina solar
3. Hanwha QCELLS
4. Canadian Solar
5. Ja solar

• Photocell
• Solar power
• Solar generation
• solar collector

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• White solar panels - a small "revolution" in solar energy, 10/30/2014, NashaGazeta.ch