Not so long ago, an autonomous system for providing electricity was something of a fantasy. But recently, such devices have become very popular. Economical residents of European countries for many years use solar panels to provide their own homes with electricity.
In our country, this innovation is still at the stage of development, although some homeowners have already managed to appreciate the benefits of such devices. First of all, this is due to the constantly growing tariffs for electricity and other utilities. Thanks to the constant improvement of modern technologies, the cost of solar cells is slowly but surely falling, which makes them more affordable for the average consumer.
- 1 How does the solar battery work?
- 2 Solar panels - the principle of operation
- 3 Silicon Converters of Solar Energy
- 4 Polymer to convert solar energy
- 5 The work of the solar battery in bad weather
How does the solar battery work?
The design of different models of devices for converting solar energy into electricity has the same elements. Most batteries consists of the following components:
- a device that generates direct current;
- battery pack;
- constant current to variable converter.
In turn, the design of the solar battery consists of a photoelectric converter. At the same time in the manufacture of such conversion components use silicon - a rather expensive natural material. Today is considered two main types photoelectric converters:
- converters in the manufacture of which used single-crystal silicon;
- devices made of polycrystalline material.
The most important technical parameters of all solar cells include them effective power factor. This criterion determines the cost-effectiveness and quality of the conversion device. Net power is determined on the basis of current and voltage, which will depend on the degree of intensity of solar light fluxes falling on the photovoltaic cells.
It should be noted that the current value at the output of the solar battery depends not only on the intensity of the sun, but also on the dimensions of the receiving elements. During rain or in winter, when constantly overcast, the power and voltage indices are significantly reduced, due to decreasing output current.
If the battery is closed on any load with resistance, then a current begins to flow through such a circuit the value of which will depend on the quality of the conversion elements and the intensity of the solar flux. rays. In this case, the power indices emitted during the load will be equal to the magnitude of the current and voltage multiplied together.
The maximum power indicators consumed by electrical devices can be achieved only with optimal resistance, which should correspond to the peak value of the efficiency of the solar battery. In addition, each transforming device has its own optimal size of resistance, the value of which will depend on the parameters of photoelectric converters.
In the design of the solar battery includes individual items, connected in series or in parallel, so that the output parameters are improved. With serial connection the magnitude of the voltage increases, and in parallel, the current. Usually, in practice, a combination of connection methods is used, which allows increasing the overall output parameters of the device.
The advantage of the combined option of combining photovoltaic cells is the fact that the reliability of the solar battery greatly increases. First of all, this is due to the fact that in the event of the failure of a single element, this will practically not affect the quality of the device as a whole.
To increase the reliability of solar cells their elements shunted with diodes. In addition, 4 diodes are used for each photovoltaic cell. Due to this, individual elements that do not fall on the light do not fail. In such a situation, the output power is reduced by about a quarter.
If we neglect the installation of the diodes, then due to overheating, the elements receiving the sun's rays will break, since in the absence of light, they begin to consume current, and thanks to the use of diodes, the current will not pass through of them.
Solar panels - the principle of operation
All converters of light energy into electrical work on a fairly simple principle, which is known to most people since the school physics course. In particular, you need to remember pn transition principle. It is thanks to him that light is converted into electricity.
Such a principle of operation can be illustrated with a transistor with a cut off case. Rays of light, falling on the pn junction are converted into electric current, the appearance of which will indicate a voltmeter connected to the terminals. At the same time, if we increase the transition area, the electricity indicators will also increase. Therefore, all modern batteries have sufficiently large dimensions, allowing to fully meet the needs of consumers in electrical energy.
Every year happens improvement of materials and the design of solar cells, thereby greatly increasing the conversion rate of solar energy into electrical energy. In this case, the parameters of the current and voltage at the output of the device depend on the degree of illumination of the photo-detectors.
Silicon Converters of Solar Energy
Solar cells made of silicon, constant current is producedformed by contact with the silicon-hydrogen elements of the streams of sunlight. The peculiarity of the material is that the light fluxes reaching the surface shift the electrons from the orbit of the atom. Because of this, free electrons generate electricity. Such converters have high performance, but they have a difficult to manufacture design, due to which the price of the device increases significantly. In this case, to date, distinguish certain models of silicon devices.
- Single crystal converter, a distinctive feature of the elements of which is the general orientation of light-sensitive cells in one direction. This, in turn, allows the solar battery to work with a maximum coefficient of efficiency. But for high-quality work, photo-detectors must be constantly turned towards the light.
- Polycrystalline device works due to the plates consisting of multidirectional silicon crystals, which reduces the level of efficiency by several percent. Also, these solar cells differ in appearance, as they consist of plates with the correct shape and dark blue color. The heterogeneity of the shade and structure of such devices is due to the heterogeneity of silicon crystals and the presence of various impurities.
- Amorphous Conversion Device It represents the thinnest silicon layers obtained by deposition of the material in vacuum conditions. High-quality metal foil, glass or polymeric materials are taken as the basis. Such solar panels have a negligible efficiency compared to other converters. This is primarily due to the increased burning of the silicon layer under the influence of radiation from the sun's rays. As it became known, from practice the quality of the amorphous converter is reduced by 25% after a few months, and after a few years the solar battery stops working completely.
- Hybrid photoconverter - a device that combines amorphous panels and microcrystalline silicon. The quality of operation of the hybrid converter is close to the characteristics of the polycrystalline analogue, with the only difference that the level of efficiency even with diffused light is much higher. In addition, these solar cells can convert both ultraviolet and infrared radiation.
Polymer to convert solar energy
The polymer converter of solar energy into electric - promising option replacements of silicon analog. The device consists of a film with a polymer active layer, aluminum electrodes and a substrate with high flexibility. By combining all photocells with each other, a roll-type device is obtained.
These solar panels are quite flexible and have a small weight. At the same time, their cost is much lower than that of silicon analogues, which is an expensive material. In addition, such systems have a high environmental friendliness which is very important today.
It should be noted that polymer solar panels have low efficiency. For the general consumer, the first such devices began to be produced in Denmark. At the same time, the production procedure itself takes place due to the multi-layer printing of photocells on a special flexible film, which can be cut to any size, which is very convenient. The cost of the film element is much lower than that of silicon analogues. But to meet such a solar battery on the shelves is almost impossible. The production process only enters the initial stage of development.
The work of the solar battery in bad weather
The solar cell is a wonderful source of electricity, invented by man. But due to the fact that the main work of such devices is sunlight, then if it is raining or clouds outside, the effectiveness of their work decreases at times. This is especially true in the autumn-winter season, when the weather does not spoil a large number of sunny days.
Based on the experience of using solar sources of electricity, in the winter the ratio of energy produced drops almost 5 times. And if you take into account that the performance of such devices is initially lower than the standard electricity, the use of solar panels in the winter or in cloudy weather is practically meaningless.
Besides, when snow falls it is necessary to perform cleaning of the panels, and it should be done with utmost care, since any defect or damage to the photocells will significantly reduce the performance of the battery as a whole. And if we talk about precipitation in the form of hail, then they are simply destructive for solar batteries, since all modules from mechanical shocks of ice come into complete disrepair.
Naturally, today it is possible to increase the performance of a solar source of electricity in cloudy weather or in winter. For this purpose, special devices were developed that track the position of the sun. This allows the monoblock to be positioned at the correct angle to the light source. In the first place - this is important for the simple reason that even a slight deviation of the battery from the sun greatly reduces its performance. And the stronger the angle of deviation, the less electricity is generated by the device.