Effectively converting free rays of the sun into energy that can be used to power homes and other facilities is the cherished dream of many green energy apologists.

But the principle of operation of the solar battery and its efficiency are such that there is no need to talk about the high efficiency of such systems yet. It would be nice to have your own additional source of electricity. Is not it? Moreover, even today in Russia, with the help of solar panels, a considerable number of private households are successfully supplied with “free” electricity. Still don't know where to start?

Below we will tell you about the design and operating principles of a solar panel; you will learn what the efficiency of a solar system depends on. And the videos posted in the article will help you assemble a solar panel from photocells with your own hands.

There are quite a lot of nuances and confusion in the topic of “solar energy”. It is often difficult for beginners to understand all the unfamiliar terms at first. But without this, it is unreasonable to engage in solar energy, purchasing equipment for generating “solar” current.

Unknowingly, you can not only choose the wrong panel, but also simply burn it when connecting it or extract too little energy from it.

The maximum return from a solar panel can only be obtained by knowing how it works, what components and assemblies it consists of, and how it is all connected correctly

First, you should understand the existing types of equipment for solar energy. Solar panels and solar collectors are two fundamentally different devices. Both of them transform the energy of the sun's rays.

However, in the first case, the consumer receives electrical energy at the output, and in the second, thermal energy in the form of a heated coolant, i.e. solar panels are used for.

The second nuance is the concept of the term “solar battery”. Typically, the word “battery” refers to some kind of electrical storage device. Or a banal heating radiator comes to mind. However, in the case of solar batteries the situation is radically different. They do not accumulate anything in themselves.

The solar panel generates a constant electric current. To convert it to variable (used in everyday life), an inverter must be present in the circuit

Solar panels are designed solely to generate electric current. It, in turn, is accumulated to supply the house with electricity at night, when the sun goes below the horizon, already in the batteries additionally present in the facility’s energy supply circuit.

The battery here is meant in the context of a certain set of similar components assembled into a single whole. In fact, it is just a panel of several identical photocells.

Internal structure of a solar battery

Gradually, solar panels are becoming cheaper and more efficient. They are now used to recharge batteries in street lamps, smartphones, electric cars, private homes and on satellites in space. They even began to build full-fledged solar power plants (SPPs) with large generation volumes.

A solar battery consists of many photocells (photoelectric converters) that convert the energy of photons from the sun into electricity

Each solar battery is designed as a block of a certain number of modules, which combine semiconductor photocells connected in series. To understand the principles of operation of such a battery, it is necessary to understand the operation of this final link in the solar panel device, created on the basis of semiconductors.

Types of photocell crystals

There are a huge number of FEP options made from different chemical elements. However, most of them are developments in the initial stages. So far, only panels made from silicon-based photovoltaic cells are currently produced on an industrial scale.

Silicon semiconductors are used in the manufacture of solar cells due to their low cost; they cannot boast of particularly high efficiency

A typical photocell in a solar panel is a thin wafer of two layers of silicon, each of which has its own physical properties. This is a classic semiconductor p-n junction with electron-hole pairs.

When photons hit the photovoltaic cell between these semiconductor layers, due to the inhomogeneity of the crystal, a gate photo-EMF is formed, resulting in a potential difference and an electron current.

Silicon wafers of solar cells differ in manufacturing technology into:

1. Monocrystalline.
2. Polycrystalline.

The former have a higher efficiency, but the cost of their production is higher than that of the latter. Externally, one option can be distinguished from another on a solar panel by its shape.

Monocrystalline solar cells have a homogeneous structure; they are made in the form of squares with cut corners. In contrast, polycrystalline elements have a strictly square shape.

Polycrystals are obtained by gradual cooling of molten silicon. This method is extremely simple, which is why such photocells are inexpensive.

But their productivity in terms of generating electricity from solar rays rarely exceeds 15%. This is due to the “impurity” of the resulting silicon wafers and their internal structure. Here, the purer the p-silicon layer, the higher the efficiency of the solar cell from it.

The purity of single crystals in this regard is much higher than that of polycrystalline analogues. They are made not from molten, but from artificially grown solid silicon crystal. The photoelectric conversion coefficient of such solar cells already reaches 20-22%.

Individual photocells are assembled into a common module on an aluminum frame, and to protect them they are covered on top with durable glass, which does not in any way interfere with the sun’s rays

The top layer of the photocell plate facing the sun is made from the same silicon, but with the addition of phosphorus. It is the latter that will be the source of excess electrons in the pn junction system.

Operating principle of solar panel

When sunlight falls on a photocell, nonequilibrium electron-hole pairs are generated in it. Excess electrons and holes are partially transferred through the pn junction from one layer of the semiconductor to another.

As a result, voltage appears in the external circuit. In this case, a positive pole of the current source is formed at the contact of the p-layer, and a negative pole at the contact of the n-layer.

The potential difference (voltage) between the contacts of the photocell appears due to a change in the number of “holes” and electrons on different sides of the p-n junction as a result of irradiation of the n-layer with solar rays

Photocells connected to an external load in the form of a battery form a vicious circle with it. As a result, the solar panel works like a kind of wheel along which electrons “run” together between proteins. And the battery gradually gains charge.

Standard silicon photovoltaic converters are single-junction cells. The flow of electrons into them occurs only through one p-n junction with a zone of this transition limited in photon energy.

That is, each such photocell is capable of generating electricity only from a narrow spectrum of solar radiation. All other energy is wasted. That is why the efficiency of FEP is so low.

To increase the efficiency of solar cells, silicon semiconductor elements for them have recently begun to be made multijunction (cascade). There are already several transitions in the new solar cells. Moreover, each of them in this cascade is designed for its own spectrum of sunlight.

The total efficiency of converting photons into electric current for such photocells ultimately increases. But their price is much higher. Here, either ease of manufacture with low cost and low efficiency, or higher returns coupled with high cost.

The solar panel can work both in summer and winter (it needs light, not heat) - the less cloudy and the brighter the sun shines, the more electric current the solar panel will generate

During operation, the photocell and the entire battery gradually heat up. All the energy that was not used to generate electric current is transformed into heat. Often the temperature on the surface of the solar panel rises to 50–55 °C. But the higher it is, the less efficiently the photovoltaic cell operates.

As a result, the same model of solar battery generates less current in hot weather than in cold weather. Photocells show maximum efficiency on a clear winter day. There are two factors at play here - a lot of sun and natural cooling.

Moreover, if snow falls on the panel, it will still continue to generate electricity. Moreover, the snowflakes won’t even have time to lie on it much, having melted from the heat of the heated photocells.

Solar battery efficiency

One photocell, even at noon in clear weather, produces very little electricity, only sufficient to operate an LED flashlight.

To increase the output power, several solar cells are combined in a parallel circuit to increase the DC voltage and in a series circuit to increase the current.

The efficiency of solar panels depends on:

• temperature of the air and the battery itself;
• correct selection of load resistance;
• angle of incidence of sunlight;
• presence/absence of anti-reflective coating;
• luminous flux power.

The lower the temperature outside, the more efficient the photocells and the solar battery as a whole work. Everything is simple here. But with load calculation the situation is more complicated. It should be selected based on the current supplied by the panel. But its value varies depending on weather factors.

Solar panels are produced with an output voltage that is a multiple of 12 V - if 24 V needs to be supplied to the battery, then two panels will have to be connected to it in parallel

Constantly monitoring the parameters of a solar battery and manually adjusting its operation is problematic. To do this, it is better to use, which automatically adjusts the settings of the solar panel in order to achieve maximum performance and optimal operating modes from it.

The ideal angle of incidence of the sun's rays on a solar battery is straight. However, if the deviation is within 30 degrees from the perpendicular, the efficiency of the panel drops by only about 5%. But with a further increase in this angle, an increasing proportion of solar radiation will be reflected, thereby reducing the efficiency of the solar cell.

If the battery is required to produce maximum energy in the summer, then it should be oriented perpendicular to the average position of the Sun, which it occupies on the equinoxes in spring and autumn.

For the Moscow region, this is approximately 40–45 degrees to the horizon. If the maximum is needed in winter, then the panel should be placed in a more vertical position.

And one more thing - dust and dirt greatly reduce the performance of photocells. Photons simply do not reach them through such a “dirty” barrier, which means there is nothing to convert into electricity. The panels must be washed regularly or placed so that the dust is washed off by rain on their own.

Some solar panels have built-in lenses to concentrate radiation onto the solar cell. In clear weather this leads to increased efficiency. However, in heavy clouds, these lenses only cause harm.

If a conventional panel in such a situation continues to generate current, albeit in smaller volumes, then the lens model will stop working almost completely.

The panels must be installed so that there are no trees, buildings or other obstacles in the path of the sun's rays.

House solar power supply diagram

The solar power supply system includes:

1. Solar panels.
2. Controller.

The controller in this circuit protects both solar panels and batteries. On the one hand, it prevents the flow of reverse currents at night and in cloudy weather, and on the other, it protects the batteries from excessive charge/discharge.

Rechargeable batteries for solar panels should be selected the same in age and capacity, otherwise charging/discharging will occur unevenly, which will lead to a sharp reduction in their service life

To transform direct current of 12, 24 or 48 volts into alternating current 220 volts you need. Car batteries are not recommended for use in such a circuit due to their inability to withstand frequent recharging. It is best to spend money and purchase special helium AGM or flooded OPzS batteries.

Conclusions and useful video on the topic

The operating principles are not too difficult to understand. And with the video materials we have collected below, it will be even easier to understand all the intricacies of the functioning and installation of solar panels. The solar power supply system for the cottage must be selected correctly. Inevitable power losses occur in the batteries, transformers and controller. And they must be reduced to a minimum, otherwise the already rather low efficiency of solar panels will be reduced to zero.

Did you have any questions while studying the material? Or do you know valuable information on the topic of the article and can share it with our readers? Please leave your comments in the block below.

Alternative energy sources that convert sunlight into electricity are becoming increasingly in demand in everyday life and industry. They are used in aviation, space development, electronics, and to create environmentally friendly transport. But the most promising industry is considered to be the energy supply of buildings: powering household appliances and home heating systems, heating hot water. The advantages include: independence from the season and utilities, the ability to accumulate energy reserves, reliability and long service life. But to achieve the maximum effect from use, it is important to know the principle of operation of batteries and comply with the conditions of their installation and operation.

Photovoltaic converters or solar storage batteries are a wafer with semiconductor properties that produces direct current when light rays hit it. The basis can be silicon (the most common type) and its compounds with copper, gallium, cadmium, indium, amphora, organic or chemical solar cells, and polymer film.

Each material has its own solar PV coefficient (from 5 to 30%) and, as a result, produces a certain power at the same luminous flux intensity. Much depends on the area of ​​the battery; a single semiconductor chip produces a small amount of energy; on average, 1 m2 of panel is required to produce 0.15 kW. The exception is innovative multilayer polymer compounds (monocrystals), their efficiency reaches 30%, but this technology is not yet available to the average consumer.

In addition to the plate, the solar battery circuit includes auxiliary devices (for transmission, distribution and storage of energy):

• Inverter or DC/DC converter.
• Storage for uninterrupted operation of the system at night or in cloudy weather.
• Voltage regulator.
• Charge tracking controller.

Depending on the area, miniature low-power batteries (up to 10 W) or large stationary panels are used. The first ones are portable (popular for charging a laptop, calculator, mobile devices). The latter often serve to supply energy and heat the house, and are usually located on the roof. Since the power of the batteries is completely proportional to solar intensity, it has become advisable to place tracking panels (which change the angle of placement depending on the movement of the Sun). The thickness of the semiconductor options is insignificant (from 10 microns to 10 cm), but taking into account the auxiliary devices, the modules weigh more, which is taken into account when calculating the load on the rafters and roof surface.

Principle of photoelectric conversion

In order to understand how a solar battery works, you should remember your school physics course. When light hits a plate of two layers of semiconductors of different conductivity, a p-n junction effect occurs; electrons from the cathode leave their atoms and are captured at the anode level. When connected to a load (battery) circuit, they give up their positively charged energy and return to the n-layer. This phenomenon is better known as “external photoelectric effect”, and the double-layer plate as a “photocell”. Most often, the same material is used: a base semiconductor with a certain type of conductivity is coated with a layer with an opposite charge, but with a high concentration of dopant impurities.

This principle of operation of solar cells has remained unchanged since the discovery of the effect; It is at the zone boundary that the electron-hole transition occurs. When exposed to sunlight, differently charged particles move in both directions; when the PV circuit is closed, they carry out work on the load. For full transmission (collection and removal of electrons), a contact system is used (the outer side of the battery resembles a grid or comb, and the back is usually solid). The higher the p-n junction area and the photoelectric conversion coefficient of the semiconductor, the more power the device produces. The physical phenomenon and operating principle do not depend on air temperature, only the intensity of sunlight is important. As a result, the efficiency of the panel is influenced by weather conditions, climate, season, and geographic latitude.

Ways to Improve Battery Efficiency

Even in central Russia, the installation of solar batteries pays for itself in 3–5 years, because the rays are absolutely free and available all year round. But to fully heat a house with 100 m2 of usable area, about 30 m2 of panels will be required. To enhance the principle of the photoelectric effect, it is recommended to carry out the following work:

1. Place the batteries on the south side at an angle of at least 30°.
2. Do not install solar panels under the shade of tall trees.
3. Once every 2 years, clean the surface from dirt.
4. Install sunlight tracking systems.

It is not worthwhile to completely abandon external energy supply; even modern complexes are not able to accumulate a sufficient amount of energy to fully power the building during prolonged bad weather. They are best used as part of a combination system.

All life on earth arose thanks to the energy of the sun. Every second, a huge amount of energy enters the surface of the planet in the form of solar radiation. While we burn thousands of tons of coal and petroleum products to heat our homes, countries located closer to the equator are sweltering in the heat. Using the energy of the sun for human needs is a task worthy of inquiring minds. In this article we will look at the design of a direct converter of sunlight into electrical energy - a solar cell.

The simplest design of a solar cell (SC) based on monocrystalline silicon is shown in the figure.

A thin wafer consists of two layers of silicon with different physical properties. The inner layer is pure monocrystalline silicon with “hole conductivity” (p-type). On the outside, it is coated with a very thin layer of “contaminated” silicon, for example with an admixture of phosphorus (n-type). (For p-, n- and p-n types, see the article on diodes). A continuous metal contact is applied to the back side of the plate. At the boundary of the n- and p-layers, as a result of charge flow, depleted zones are formed with an uncompensated volumetric positive charge in the n-layer and a volumetric negative charge in the p-layer. These zones together form a p-n junction.

The potential barrier (contact potential difference) that appears at the transition prevents the passage of the main charge carriers, i.e. electrons from the p-layer side, but freely allow minority carriers to pass in opposite directions. This property of p-n junctions determines the possibility of obtaining photo-emf when irradiating a solar cell with sunlight. When the SC is illuminated, the absorbed photons generate nonequilibrium electron-hole pairs. Electrons generated in the p-layer near the p-n junction approach the p-n junction and are carried into the n-region by the electric field existing in it.

Similarly, excess holes created in the n-layer are partially transferred to the p-layer (Fig. a). As a result, the n-layer acquires an additional negative charge, and the p-layer acquires a positive charge. The initial contact potential difference between the p- and n-layers of the semiconductor decreases, and voltage appears in the external circuit (Fig. b). The negative pole of the current source corresponds to the n-layer, and the p-layer to the positive one.

Most modern solar cells have a single pn junction. In such an element, free charge carriers are created only by those photons whose energy is greater than or equal to the band gap. In other words, the photovoltaic response of a unijunction cell is limited to the part of the solar spectrum whose energy is above the bandgap, and lower energy photons are not used. Multilayer structures of two or more solar cells with different band gaps can overcome this limitation. Such elements are called multi-junction, cascade or tandem. Because they work with a much larger portion of the solar spectrum, their photovoltaic conversion efficiency is higher. In a typical multijunction solar cell, single solar cells are arranged one behind the other in such a way that sunlight hits the cell with the largest bandgap first, and the highest energy photons are absorbed.

The photons transmitted by the top layer penetrate into the next element with a smaller bandgap, etc. The main direction of research in the field of cascade cells involves the use of gallium arsenide as one or more components. The conversion efficiency of such solar cells reaches 35%! For technological reasons, a single solar cell can only be manufactured in a small size, therefore, for greater efficiency, several cells are combined into batteries.

Solar batteries have proven themselves well in space as a fairly reliable and stable source of energy, capable of operating for a very long time. The main danger to solar cells in space is cosmic radiation and meteor dust, which cause erosion of the surface of silicon elements and limit the life of the batteries. For small inhabited stations, this current source will apparently remain the only acceptable and sufficiently effective one.

With constantly rising prices for electricity, you inevitably begin to think about using natural sources for power supply. One of these possibilities is solar panels for your home or garden. If desired, they can fully provide all the needs of even a large house.

Design of a solar power supply system

Converting the sun's energy into electricity - this idea kept scientists awake for a long time. With the discovery of the properties of semiconductors, this became possible. Solar cells use silicon crystals. When sunlight hits them, a directed movement of electrons is formed in them, which is called an electric current. When connecting a sufficient number of such crystals, we obtain quite decent currents: one panel with an area of ​​​​a little more than a meter (1.3-1.4 m2 with a sufficient level of illumination can produce up to 270 W (voltage 24 V).

Since the illumination changes depending on the weather and time of day, it is not possible to directly connect devices to solar panels. We need a whole system. In addition to solar panels, you need:

• Battery. During daylight hours, under the influence of sunlight, solar panels generate electric current for the home or cottage. It is not always used in full; its excess accumulates in the battery. The accumulated energy is consumed in inclement weather.
• Controller. Not a mandatory part, but desirable (if you have enough funds). Monitors the battery's charge level to prevent it from over-discharging or exceeding its maximum charge level. Both of these conditions are detrimental to the battery, so having a controller extends the life of the battery. The controller also ensures optimal operation of solar panels.
• DC to AC converter (inverter). Not all devices are designed for direct current. Many operate on alternating voltage of 220 volts. The converter makes it possible to obtain a voltage of 220-230 V.

Solar panels for the home are only part of the system

By installing solar panels for your home or cottage, you can become completely independent from the official supplier. But for this you need to have a large number of batteries, a certain number of batteries. A kit that produces 1.5 kW per day costs about $1000. This is enough to meet the needs of a summer house or part of the electrical equipment in the house. A set of solar panels for producing 4 kW per day costs about $2,200, for 9 kW per day - $6,200. Since solar panels for home are a modular system, you can buy an installation that will provide part of the needs, gradually increasing its productivity.

Types of solar panels

With rising energy prices, the idea of ​​using solar energy to generate electricity is becoming increasingly popular. Moreover, with the development of technology, solar converters are becoming more efficient and, at the same time, cheaper. So, if you wish, you can meet your needs by installing solar panels. But they come in different types. Let's figure it out.

The solar battery itself is a number of photocells located in a common housing, protected by a transparent front panel. For household use, solar cells are produced based on silicon, since it is relatively inexpensive, and elements based on it have a good efficiency (about 20-24%). Monocrystalline, polycrystalline and thin-film (flexible) solar cells are made based on silicon crystals. A certain number of these photocells are electrically connected to each other (series and/or parallel) and connected to terminals located on the housing.

Photocells are installed in a closed housing. The solar battery housing is made of anodized aluminum. It is lightweight and non-corrosive. The front panel is made of durable glass, which must withstand snow and wind loads. In addition, it must have certain optical properties - have maximum transparency in order to transmit as many rays as possible. In general, a significant amount of energy is lost due to reflection, so the requirements for the quality of glass are high and it is also coated with an anti-reflective compound.

Types of photocells for solar panels

Solar panels for the home are made from three types of silicon cells;

If you have a pitched roof and the facade faces south or east, there is no point in thinking too much about the space occupied. Polycrystalline modules may be quite suitable. For the same amount of energy produced, they cost slightly less.

How to choose the right solar panel system for your home

There are common misconceptions that make you spend extra money on overly expensive equipment. Below are recommendations on how to properly build a power supply system from solar panels and not spend extra money.

What to buy

Not all components of a solar power plant are vital for operation. Some parts can be done without. They serve to increase reliability, but without them the system is operational. The first thing to remember is to purchase solar panels at the end of winter, beginning of spring. Firstly, the weather at this time is excellent, there are many sunny days, the snow reflects the sun, increasing the overall illumination. Secondly, discounts are traditionally announced at this time. The following are the tips:

If you use only these tips, and connect only equipment that operates on constant voltage, a solar panel system for your home will cost a much more modest amount than the cheapest kit. But that is not all. You can leave some of the equipment “for later” or do without it altogether.

What can you do without?

The cost of a set of solar panels for 1 kW per day is more than a thousand dollars. Considerable investment. You will inevitably wonder whether it is worth it and what the payback period will be. At current rates, you will have to wait for more than one year until you get your money back. But costs can be reduced. Not at the expense of quality, but due to a slight decrease in the operating comfort of the system and due to a reasonable approach to the selection of its components.

So, if your budget is limited, you can get by with several solar panels and batteries, the capacity of which is 20-25% higher than the maximum charge of solar panels. To monitor the condition, buy a car clock that also measures voltage. This will save you from having to measure the battery charge several times a day. Instead, you will need to look at your watch from time to time. That's all for the start. In the future, you can purchase additional solar panels for your home and increase the number of batteries. If desired, you can buy an inverter.

Determining the size and number of photocells

Good 12-volt solar panels should have 36 cells, and 24-volt solar panels should have 72 solar cells. This amount is optimal. With fewer photocells you will never get the stated current. And this is the best option.

You should not buy dual solar panels - 72 and 144 elements, respectively. Firstly, they are very large, which is inconvenient for transportation. Secondly, at abnormally low temperatures, which we periodically experience, they are the first to fail. The fact is that the laminating film greatly decreases in size in cold weather. On large panels, due to high tension, it peels off or even breaks. Transparency is lost and productivity drops catastrophically. The panel is being repaired.

Second factor. On larger panels, the thickness of the body and glass should be greater. After all, windage and snow loads increase. But this is not always done, as the price increases significantly. If you see a double panel, and the price for it is lower than for two “regular” ones, it’s better to look for something else.

Once again, the best choice is a 12-volt home solar panel consisting of 36 solar cells. This is the best option, proven by practice.

Technical specifications: what to look for

Certified solar panels always indicate operating current and voltage, as well as open-circuit voltage and short-circuit current. It is worth considering that all parameters are usually indicated for a temperature of +25°C. On a sunny day on the roof, the battery heats up to temperatures significantly higher than this figure. This explains the presence of higher operating voltage.

Also pay attention to the open circuit voltage. In normal batteries it is about 22 V. And everything would be fine, but if you carry out work on the equipment without disconnecting the solar panels, the no-load voltage will damage the inverter or other connected equipment that is not designed for such a voltage. Therefore, during any work - switching wires, connecting/disconnecting batteries, etc. etc. - the first thing you should do is disconnect the solar panels (remove the terminals). Having gone through the diagram, you connect them last. This procedure will save you a lot of nerves (and money).

Case and glass

Solar panels for home have an aluminum body. This metal does not corrode and has sufficient strength and is light in weight. A normal body must be assembled from a profile containing at least two stiffeners. In addition, the glass must be inserted into a special groove, and not fixed on top. All these are signs of normal quality.

When choosing a solar battery, pay attention to glass. In normal batteries it is not smooth, but textured. It is rough to the touch; if you rub it with your nails, you can hear a rustling sound. In addition, it must have a high-quality coating that minimizes glare. This means that nothing should be reflected in it. If reflections of surrounding objects are visible at any angle, it is better to find another panel.

Selecting the cable cross-section and the fineness of the electrical connection

Solar panels for your home must be connected using a single-core copper cable. The cable cross-section depends on the distance between the module and the battery:

• distance less than 10 meters:
  • 1.5 mm2 per 100 W solar battery;
  • for two batteries - 2.5 mm2;
  • three batteries - 4.0 mm2;
• distance more than 10 meters:
  • to connect one panel we take 2.5 mm2;
  • two - 4.0 mm2;
  • three - 6.0 mm2.

You can take a larger cross section, but not smaller (there will be large losses, but we don’t need it). When purchasing wires, pay attention to the actual cross-section, since today the declared dimensions very often do not correspond to the actual ones. To check, you will have to measure the diameter and calculate the cross-section (you can read how to do this).

When assembling the system, you can draw the positives of solar panels using a multi-core cable of a suitable cross-section, and use one thick cable for the negative. Before connecting to the batteries, we pass all the “pluses” through diodes or diode assemblies with a common cathode. This prevents the battery from shorting out (which could cause a fire) if the wires between the batteries and the battery are shorted or broken.

Diodes use types SBL2040CT, PBYR040CT. If you don’t find any, you can remove them from old power supplies of personal computers. There are usually SBL3040 or similar ones. It is advisable to pass through diodes. Don’t forget that they get very hot, so you need to mount them on a radiator (you can use just one).

The system also requires a fuse box. One for each consumer. We connect the entire load through this block. Firstly, the system is safer this way. Secondly, if problems arise, it is easier to determine its source (by a blown fuse).

Alternative energy sources are becoming more and more relevant every day. The reason for this is environmental friendliness, renewability, and low cost. Solar energy is one of the most profitable sources of energy. For the next few billion years, it will continue to illuminate our planet, giving off a huge amount of energy, unlike gas and oil. Today we have learned to use this source using a solar panel system, but few people understand principle of operation of a solar battery. Let's figure it out.

First you need to understand that home solar power system These are not just those black or bluish panels that are installed on the roofs of houses. These light receivers are only one of four components of the overall system, which includes:

The principle of operation of a solar battery

A solar battery or solar module is a key element in a solar alternative power supply system. It is what converts sunlight into usable electricity. The battery is based on a single crystal of artificial silicon, on both sides of which a layer of boron and phosphorus is applied.

Electric current is formed where there is a potential difference or "+" and "-". The additional coating serves this purpose. They are usually called:

• n-type or a coating with excess electrons (phosphorus);
• p-type or a coating with a lack of electrons, so-called “holes” (boron);

When photons of sunlight hit the coating n-type, free electrons begin to move into the zone p-type generating electricity or so-called. pn junction. The side on which the sun's rays fall is of fundamental importance.

Structure of a solar battery

1. sunlight;
2. top conductor;
3. n-type layer (phosphorus);
4. p-n junction zone;
5. p-type layer (boron);
6. lower conductor;

Both sides of the solar battery are covered with protective layers to prevent mechanical damage. The upper (sunny) side is additionally coated with an anti-reflective light-absorbing coating, which increases the level of light absorption.

Separate light receiving blocks or modules are interconnected in panels, increasing the overall power of the system.

Today, the cost of panels is one of the most negative factors determining the purchase of panels. The payback period in areas with long daylight hours is 5-10 years, but often much longer. The Chinese have significantly succeeded in their desire to reduce the cost of solar cells by replacing single crystal silicon with polycrystals, but this affected the already low efficiency of batteries. Average efficiency solar panels operation varies from 13 to 17%. The highest efficiency achieved was 24%.

Finally, a film about the principle of operation of a solar battery with comments from experts: