Solar cells are gaining popularity among the public. They are installed on the roofs of houses, vehicles. Some of them are adapted even for electronics, in watches. At the moment, they have become a full-fledged alternative to electric energy or act as a supplement.
How do they work?
Solar modules are the most important element in a photovoltaic system. They are a panel, which includes solar cells made of silicon.
To obtain electricity, all these components are assembled in blocks, which are then tightened with a laminated film - this is necessary for sealing. After which everything is placed in the frame. The device is quite simple, but assembling at home will be problematic. It is impossible to assemble a photovoltaic cell on its own, which cannot be said about the panel.
Kinds
Solar cells are divided into several types. Among them, three can be distinguished:
- Monocrystalline. In the process of its manufacture, material in the form of pure silicon is used. This basis allows you to get more efficiency from work. Efficiency in this case varies from 15 to 20%.
- Amorphous silicon. At the time of production, the system is used - the evaporation phase. Silicon is coated with a protective layer. Among the advantages of silicon solar cells can be attributed an acceptable cost, which is obtained due to the simple technology used in production. Such systems are large in size. Efficiency varies in the region from 5% to 8%.
- Polycrystalline. This solar cell is manufactured on an amorphous-silicon basis. In the manufacturing process is not subjected to stretching. It has a low cost. It can be used not only in everyday life, but also in industry. Efficiency is from 10 to 14%.
Pros and Cons of a Solar Battery
Solar cell panels are made up of solar cells that convert energy from the sun to electricity during operation.
The following points can be attributed to a number of advantages:
- The whole design of the battery is quite simple, it completely lacks moving parts. The work is carried out stably and without interruptions, the level of reliability is high.
- Installation work is not difficult. No costly system maintenance required.
- Energy from the sun is immediately converted into electricity, no extra time is required.
- Energy is generated throughout the day while the sun is present. In some cases, you can get electricity in cloudy times, but at the same time, the efficiency decreases.
- The service life is long, it is measured not in years, but in tens of years.
- In the production process, environmentally friendly materials are used, which is considered very important in modern society, where there is a difficult environment with ecology.
Despite all the advantages, negative aspects can occur in the work:
- Semiconductors that are made of silicon have a high cost. This material is considered the main elements in the entire system. It affects both the cost of the panel itself and the cost of energy received.
- Efficiency is low. Today, battery power per square meter is approximately 120 watts. This indicator is so insignificant that there is completely no possibility to use the received electricity for lighting devices of a small room.
- Electricity generation depends on daylight hours, weather conditions and seasons. For example, in winter, the level of energy received is significantly reduced. This is due to cloudy skies, fogs and short daylight hours.
Where can i use it?
These panels are widely used not only in everyday life, in the process of life, but also in industry and in production:
- from them charge the batteries of household electrical appliances;
- charging an electric car;
- with their help it is possible to provide whole buildings with electric energy;
- in some cases, it is possible to use in certain settlements;
- they can receive energy even in space.
All the energy that is generated during daylight hours is stored in batteries, after which the devices can work even in the dark.
What is the principle of operation and device?
Solar cells work on the same principle as at the time of the first development. This principle is familiar to everyone, since it was studied in the school curriculum, conducting physical experiments. The transistor, in which there was no top cover, contributed to the ingress of light on the p and n junctions.
After the voltmeter was connected, it was possible to see that a small amount of energy was released at the moment of exposure to sunlight. Previously, scientists conducted experiments in work, increased the area for transitions. As a result, solar panels appeared.
The design of the solar system of elements contains:
- Surface made of clear glass. It is on it that the rays of the sun fall.
- Glasses are attached to the hard edges of the panel. They are plates made of metal, while simultaneously performing the function of positive electrodes.
- Solar chemical element. Type of silicon p.
- Type of silicon n.
- The lower substrate is made of metal, which is designed to perform the function of negative electrodes.
It is worth knowing that it is impossible to receive energy from the sun throughout the whole day. Batteries are not able to function at night. In winter, daylight hours are reduced. At such moments, the main device requires an addition in the form of an energy storage device.
In most cases, use an electric battery. It is connected to the panel and accumulates the generated energy, as a result of which work is carried out in the evening.
The level of efficiency is completely dependent on the material used. For example, when using single-crystal silicon, it is almost 20%, polycrystalline silicon reduces this figure by 10%. The level of efficiency can be affected by the smoothness of the surface, the temperature of the air, the location of the batteries to the sun.
What is the relevance of use?
Today, the use of environmentally friendly materials is most relevant. Electricity, which is obtained at power plants - nuclear, water, thermal, is constantly becoming more expensive. This is due to expensive production. At the moment when the solar battery is used, a person can rightfully consider himself independent, even from a state that offers electricity for use at an overpriced cost.
If you spend a certain amount of money once, then you can completely forget about utility bills, meters, utilities. At the moment when these panels are installed, the whole house is translated. This includes not only light, but also heating, plumbing - hot water.
Radiation from the sun is an excellent source of electricity. And most importantly - this source is free, environmentally friendly and inexhaustible.
Monocrystal production steps
Most solar cells are produced using polycrystalline and single crystalline silicon. The production process requires a lot of time, effort and money.
The main stages of production based on single-crystal silicon include:
- Silicon production. In order to obtain silicon, quartz sand is used, which contains a large amount of silicon dioxide. Such sand goes through several stages of cleaning, which allows to completely eliminate oxygen. This is due to melting at high temperature using chemicals.
- Getting the crystal. After cleaning, silicon becomes transparent. Crystals begin to grow to order the structure. The process is as follows: silicon pieces are placed in a crucible, heated and melted. Crystal samples are added to the molten mass, which are evenly distributed over the entire surface and begin to grow in layers. This process requires a lot of time, resulting in a homogeneous crystal of large size.
- Processing process. This process begins with the measurement and further processing of the crystal to give the desired shape. When leaving the crucible, the crystal has a round shape, which is inconvenient for further use. For use, it must be in the shape of a square. After the finished material was treated with steel threads, it is cut into identical plates using wire. The size of the plates varies from 0.25 to 0.3 centimeters. After that, they are subject to cleaning, checking for marriage and the level of energy that can be generated.
- Development of a photovoltaic cell. In order for silicon to be able to generate electrical energy, boron with phosphorus is added to it. After processing, phosphorus is a free electron of type n, and the side with boron does not contain these electrons and has type p. Thus, a transition appears between the two sides.
- Assembly process. Initially, the plates are connected in a chain, and then in a block. One plate has an average power of 2 V and 0.6 W voltage. Battery power is completely dependent on the number of cells. The voltage level is obtained from the connection sequence. All elements and modules are connected in parallel to each other. All cells are coated with a special film, transferred to the surface of the glass and placed in a frame with a rectangular shape. After the module is ready, it passes the test. After a full check, it is ready to use.
Solar panels can be connected to each other in parallel, in series or in parallel in series. The choice depends entirely on what level of voltage you need to get during operation.
Polycrystalline Silicon Production Process
The process of manufacturing a module based on polycrystalline silicon is carried out in the same way as with single-crystal silicon. The difference is present only in growing crystals. Several methods are provided for this, but at the moment, only one has gained popularity - the Siemens process. The whole essence of the method is that silane is initially reduced and free silicon is precipitated. This is done by interacting with a special mixture that contains hydrogen and silane elements using a temperature regime ranging from 600 to 1350 degrees heat.
This is how the process of manufacturing solar panels occurs.
How to make a solar battery at home?
Many are inclined to assume that batteries with solar cells with their own hands are assembled quite difficult, even almost impossible. In fact, everything is different. It will take a lot of effort, but the process itself is not difficult, as it seems initially. The main difficulty that can be encountered in the process of work is the collection of a solar cell with your own hands. If you manage to create such a mechanism on your own, then you can think about not only refusing to pay for utilities, but also for selling your own business. At the moment, solar panels are very relevant for the sale of energy reproduced by them. Most importantly, payment is made in one of the most stable currencies - the euro. Is the production of solar cells is not worth attention?
In order to work with photo cells, you need to have skills and experience in this field. First of all, this concerns soldering, as well as respect for all elements. To work, you need to have a good soldering tool that is suitable for delicate work. Create your own single and polycrystals will not work. For this, ready-made blanks can be used.
Photocells
The first step in the work is the selection of the necessary photo cells. To operate the battery, you can use silicon with poly - and monocells. The most important thing is to take into account the level of performance and nuance when working. For example, in monocells the efficiency is higher, but in polycells significant energy is lost in cloudy times.
All cells are divided into classes. In total, four of them are distinguished. Class A has the best quality with no defects. This class is used in work by reputable and large organizations, companies. Performance at work is high, but the cost will be appropriate.
When the battery is manufactured on its own, it is possible to choose class B. Efficiency is lower than that of the previous elements, while the cost is significantly different. Some organizations use this class in the manufacture of batteries for sale, which explains the low efficiency.
Some people buy everything they need through online stores. If you go to a specialized store, you can immediately buy all the components. Then you do not have to wait for delivery.
Sets
To collect a solar cell, only cells will not be enough, since they must somehow be connected to each other according to the scheme. This will require the use of conductors and additional materials. That is why some manufacturers offer a ready-made set for purchase, where all the material that is needed at work is already present.
Such a set can include up to 72 elements, conductors, buses, diodes for the circuit, as well as a pencil, which includes special acid for soldering.
Some kits may contain ready-made photocells to which the conductors are soldered. For collection it will be enough only to collect everything according to the scheme and connect. This option is most optimal when the solar cells for assembling solar cells are connected manually. The material is very small and brittle, which causes a number of problems in the process.
Soldering
In the event that all the material - elements and conductors - were purchased separately, then the whole process of soldering solar cells will look like the following:
- Conductors are cut to the desired length. It’s best to do this work by template.
- The conductors are neatly superimposed on the photocell.
- Acid and solder are applied to the place of soldering. To avoid displacement, you can put a heavy object on one end.
- The conductor must be soldered carefully. Since the cells are quite fragile, it is not recommended to force them.
This work is very painstaking, not the fact that it will be possible to do everything right the first time, you may need to repeat the whole process several times. If we study the norms, we can understand that the deposition of silver conductors is designed for three soldering cycles. There are times when solders are applied in advance on the conductors, which the manufacturer warns about right away. But it is best to apply it additionally. In the process, it is forbidden to put solar cells on top of each other, since you can damage them due to high pressure.
Sealing
The final stage of work is the sealing of all elements. But before you start this, you need to pay attention to the reliability of adhesions. A multimeter is used for this. Verification can be carried out after completion of all work or during the entire process, after soldering each individual element.
Silicone is often used for the sealing process. First of all, it is applied to the joints of the elements, and then on the entire panel surface. For such work, you can use a brush, but you need to use it only for joints, since it is possible to easily move cells from a place. After everything has dried, you can close the lid.
Choosing a battery in the house
At the moment, you can find batteries with two types of solar cells: monocrystalline, polycrystalline.
Each type has pros and cons in the work, which you need to know in advance, before making a purchase.
Opportunities of the market and production do not stand still, new items regularly appear, in the manufacturing process of which various technologies are used. Before making a choice, it is recommended to pay attention to the characteristics of solar cells: the level of efficiency, the presence of a battery that can accumulate energy during daylight hours and generate it in the dark. All these data are provided in advance by the manufacturer, they can be found in a specialized store. It is best to preliminarily find information on the Internet or discuss with experts which option will be the best.