Solar cells with high efficiency. New record! Efficiency of solar panels

Today, various types of solar panels are gaining more and more popularity. And for good reason, because in addition to the fact that the population of planet Earth is beginning to think about environmentally friendly energy sources, solar panels are also becoming more and more energy efficient. Of course, the most basic thing that is included in any solar energy supply system is panels or batteries, so it’s important to understand what’s what. Of course, the system is much more complicated and includes all sorts of stabilizers, inverters, etc., but this is not the main point.

What are the types solar panels or panels?

On at the moment The types of solar panels are so diverse and there are such a great variety of them that every consumer who wants to acquire a similar energy source asks the question: “ How to choose a solar battery? What types of solar panels are there?“This is what our article is about: we will try, without getting into the jungle of technology, to understand what types of batteries or panels powered by solar energy are divided into, because the market is replete with advantageous offers and we want to sell you this or that system. First of all, solar modules differ in materials, operating principle and production principle. So let's figure out what and why.

Silicon solar cells

This type of solar panels differs primarily in its material, which, as the name suggests, is represented by silicon. These are the most popular batteries on the market today. This is due to the fact that silicon is a relatively easily available material, it is inexpensive and at the same time has good performance indicators compared to competitive types of solar modules. They are produced not only from silicon, but also from mono, polycrystalline and amorphous silicon. What's the difference?

Monocrystalline solar cells

For the production of monocrystalline solar cells, purified, purest silicon is used. This type of solar panel looks like silicone honeycombs, or cells, that are connected into one structure. After the purified single crystal hardens, it is divided into super thin plates, up to 300 microns thick. Such finished plates are connected by a thin grid of electrodes. Compared to amorphous batteries, these are more expensive, because their production technology is much more complex. Moreover, such batteries are worth choosing at least for their high coefficient of performance (efficiency). At the 20% level. Yes, this is a good indicator for solar panels.

Polycrystalline solar panels

For that To obtain polycrystals, the silicon substance is slowly cooled. This approach to production technology is much cheaper than the previous type of panels, which is why this type costs less. At the same time, less energy is required for production, and this again has a beneficial effect on the price. But what needs to be sacrificed? Therefore, such batteries Efficiency is lower - up to 18%. This drop in the coefficient is associated with formations inside the polycrystal, which reduce the efficiency. To better understand the differences between the first and second types of batteries, take a look at the table:

Comparison table of monocrystalline and polycrystalline solar panels:

Amorphous solar panels or amorphous silicon batteries

• This type of solar cells can be classified as silicon (because manufacturing material - silicon) and to film batteries, because they are made according to the principle of producing film batteries. But still there are differences.

• Here It is not silicon crystals that are used, but the so-called silane (hydrogen silicon). It is applied to the substrate, inside the batteries. The efficiency of this type of solar panels is much lower - about 5%. But it's not that bad! There are also advantages, including: much better absorption (20 times better), works better in the absence of direct sun, when it is cloudy, elasticity of the panels.

• Also There are combinations of mono and polycrystalline panels with amorphous ones. This combination allows you to combine the advantages of two various types. For example, batteries perform better when the sun is not enough for conventional crystalline batteries.

Film solar cells

Film panels are the next step in the development of solar power sources. A step that is dictated primarily by the need to reduce prices for battery production and the desire to increase energy efficiency.

Film batteries based on cadmium telluride

• Cadmium is a material that has high level light absorption, discovered as a solar cell material in the 70s. Today, this material is no longer used only in space, in low-Earth orbit, but is also actively used as a material for solar panels for ordinary, home use.

• The main problem in using such material is its toxicity.. However, research suggests that cadmium levels. that escapes into the atmosphere is too small to harm human health. Also, despite the low efficiency of around 10%, the cost per unit of power in such batteries is less than that of analogues.

Film panels based on copper-indium selenide

Type of solar panels made of such materials use copper, indium, selenium as a semiconductor. By the way, indium is the main, very required material, which is used in the production of liquid crystal monitors. Therefore, leaving such material for these purposes, gallium is often used, which replaces indium in its functions. The efficiency here is higher than that of cadmium telluride batteries - about 20%.

Polymer solar panels

A type of solar panel that was recently invented and began to be produced. Here polyphenylene, furellenes, and copper phthalocyanine act as conductors. Moreover, such a film is very thin - about 100 nm. Despite low level Efficiency, about 5%, it is still possible to highlight the reasons why it is worth choosing this type of solar panels: Availability of materials, low cost, absence of harmful emissions into the atmosphere. So such batteries are great for consumers, because they have excellent elasticity and environmental friendliness.

Comparison table: types of solar panels and efficiency levels

Finally, I would like to compare efficiency factors of each type of solar panels, but do not forget that in addition to efficiency there are many other factors that can characterize each type from both the good and the bad side.

What are concentrating solar modules?

Concentrating modules help to use the area of ​​solar panels more efficiently, resulting in space savings of almost two times. However, such a system is complicated by the need to install mechanical module, which would turn the lenses towards the sun. Such installations are especially necessary in places where there is ample direct radiation from the sun throughout the year.

Photosensitized batteries

Photosensitizing dye again helps optimize solar energy intake, but solar panels working on this principle are more reminiscent of the process of photosynthesis in nature. However, for now this is only a conceptual idea that has no implementation. Who knows, maybe by the time you get ready to buy solar panels, they will already be on sale in full force on the market.

Well, have you figured out what solar panels are? We hope this article will help you decide which battery to install for your home., but if after reading you have even more questions, you are welcome to visit our website, where you will find all the information about solar panels and power supplies powered by solar energy, as well as various types solar panels.

The record holder for efficiency among solar batteries available on the market today are solar batteries based on multilayer photocells, developed by the Fraunhofer Institute for Solar Energy Systems in Germany. Since 2005, their commercial implementation has been carried out by Soitec.

The size of the photocells themselves does not exceed 4 millimeters, and the focusing sunlight they are achieved by using auxiliary concentrating lenses, thanks to which saturated sunlight is converted into electricity with an efficiency reaching 47%.

The battery contains four p-n junction, so that four different parts of the photocell can effectively receive and convert radiation of a specific wavelength, from sunlight concentrated 297.3 times, in the wavelength range from infrared to ultraviolet.

Researchers led by Frank Dimiroth initially set themselves the task of growing a multilayer crystal, and a solution was found - they spliced ​​growth substrates, and the result was a crystal with different semiconductor layers, with four photovoltaic subcells.

Multilayer photocells have long been used on spacecraft, but now solar stations based on them have been launched in 18 countries. This is becoming possible thanks to improved and cheaper technology. As a result, the number of countries equipped with new solar stations will increase, and there is a tendency for competition in the market for industrial solar panels.

In second place are solar batteries based on Sharp three-layer photocells, the efficiency of which reached 44.4%. Indium gallium phosphide is the first layer of the solar cell, gallium arsenide is the second, and indium gallium arsenide is the third layer. The three layers are separated by a dielectric, which serves to achieve a tunnel effect.

The concentration of light on the photocell is achieved thanks to a Fresnel lens, like the German developers - the light of the sun is concentrated 302 times and converted by a three-layer semiconductor photocell.

Scientific research into the development of this technology has been continuously conducted by Sharp since 2003 with the support of NEDO, a Japanese public management organization promoting scientific research and the development and dissemination of industrial, energy and environmental technologies. By 2013, Sharp had achieved a record of 44.4%.

Two years before Sharp, in 2011, the American company Solar Junction had already released similar batteries, but with an efficiency of 43.5%, the elements of which were 5 by 5 mm in size, and focusing was also carried out by lenses, concentrating the light of the sun 400 times. The solar cells were three-junction germanium-based cells, and the team even planned to create five- and six-junction solar cells to better capture the spectrum. Research is still ongoing by the company.

Thus, solar panels made in combination with concentrators, which, as we see, are produced in Europe, Asia, and America, have the highest record efficiency. But these batteries are mainly manufactured for the construction of large-scale ground-based solar power plants and for efficient power supply to spacecraft.

Recently, a record has been set in the field of conventional consumer solar panels, which are affordable for most people who want to install them, for example, on the roof of a house.

In mid-autumn 2015, Elon Musk's company SolarCity introduced the most efficient consumer solar panels, the efficiency of which exceeds 22%.

This indicator was confirmed by measurements carried out by the Renewable Energy Test Center laboratory. The Buffalo plant already sets a daily production target of 9 to 10 thousand solar panels, the exact characteristics of which have not yet been reported. The company already plans to supply at least 200,000 homes annually with its batteries.

The point is that optimized process allowed the company to significantly reduce the cost of production, while increasing the efficiency by 2 times compared to widespread consumer silicon solar panels. Musk is confident that his solar panels will be the most popular among homeowners in the near future.

I scream and cry, this is probably how the video should have started, but many people immediately start thinking in the wrong direction. Yes, there is a lot of material about the efficiency of solar panels. There are so many that everyone is looking for a solar panel with an efficiency of 30 -50% and no matter how much they cost. Wait, what? Are you really one of those people who think that today the efficiency of panels is what is in open access it's not enough. In reality, is 22 -28% not enough?

Do you want an example of what actually has low efficiency, and we’ll talk about solar panels produced in 1990 with an efficiency of about 10%, and you know, now I can definitely say with confidence that the fairy tale that everyone who doesn’t understand is spreading on the Internet, this is outright untrue. And in order to say this with confidence, I needed to buy 2 panels with my own money, install them in operation, and monitor them for about a year different options connections.

Well, the verdict is ready.

The efficiency of older solar panels of earlier production before 2010 is significantly lower than the efficiency of modern panels, and here we are not even talking about the reduction in cost of the latter, but specifically about the production technology. We will not touch on the fact that modern ones are thinner, have a new absorbent coating, which is more effective than older panels and fades less. No, we'll just talk about efficiency.

To begin with, what is efficiency - coefficient of performance.

So, in simple language, this is how efficient solar panels work now, but not in the future, since the further and longer the solar panel works, the efficiency getting lower. What if you pull and load solar panels? short circuit, spiral, or IR lamps, as some do. The efficiency of solar panels will simply melt several times faster.

So, there really is no such information, even if it is so rough, especially since solar panels are so worn out that it is difficult to find in our country. And what do we end up with?

It’s simple: when there is sun, the solar panels produce almost all their power, but the operating and idle voltage drops. Yes, the current dropped a little, about 0.5 - 1A. And we could end here, taking into account the words of most bloggers, but no, our efficiency has also dropped, now solar panels produce less both in voltage and current, in cloudy weather or in reflected light. This is a drop in efficiency or wear of the panel. It seems to work, but it doesn’t seem to work in bad weather.

You think everything, but that’s not the case, I’m already used to telling everything or almost everything, even if slippers are flying at me in the present tense, and in the future they are collected saying, but why didn’t you know :) I’ll tell you another problem with worn-out solar panels.

Namely! The thing is that due to the wear and tear of the solar panel and the severely damaged and burnt-out absorbent and light-absorbing coating, by the way, some people who are not in the know call this coating a dissipative coating or something else. But correctly absorbing and absorbing light, its task is to protect the silicon wafer, and the structure of the element itself, and absorb sunlight more effectively! Much of the efficiency depends on this thin layer.

So, when it collapses and burns out, the solar cells begin to heat up more intensely, and their power drops. The effect is very similar to a semi-pierced or overheated semiconductor, which seems to work, but heats up and its characteristics drop. So, since a solar cell is the same conductor with p-n transition, only larger size All electronics rules also apply to solar cells.

And the most important thing is that you cannot combine old solar panels with new ones, because when the output power on the weak ones drops, but on the new ones there is still power, the old panels will pull part of the power onto themselves as a load, thereby heating the street instead of working!

That's how things are. And now I will talk about this more often, so that the majority of both storytellers and people who are not in the subject will have more competent information. And if there are real observations, then there is information on how to extend the life of solar cells.

Much confusion today exists around the concept of solar system efficiency, which is important criterion their cost. The concept of solar panel efficiency refers to the percentage of sunlight falling on a panel that is converted into electricity for further use. Various materials solar panels create different efficiencies, even the same manufacturing companies have different conversion efficiency indicators. The increase in efficiency is the best way reduce solar energy costs.

The efficiency of a solar cell depends on the cleanliness of the plates that are used as raw materials in manufacturing. In addition, it is very important whether the panel is monocrystalline or polycrystalline. Most large companies are concentrating their efforts on increasing efficiency to reduce costs in the relentless use of solar energy.

Let's consider the general range of efficiency of solar cells, based on different types elements and various technologies.

There are the following - polycrystalline or monocrystalline silicon. Multi-solar cells have lower efficiency than batteries made from monocrystalline cells.

Solar cell efficiency can vary from 12% to 20% for conventional monocrystalline silicon. In usually installed ones, the calculated efficiency is 15% and depends on the type of silicon itself. Some of the world's manufacturers are constantly improving efficiency in order to reduce their costs and stay ahead of their rivals in this competitive industry. Others maximize the efficiency of crystalline solar cells using large scale production.

Polycrystalline solar cells have a lower cost than monocrystalline ones and have an efficiency in the range of 14-17%.

Thin-film technology, in contrast to carbon-silicon materials, has a number of advantages.

Amorphous silicon C-Si technologies have the lowest average efficiency, but they are the cheapest.

Copper-indium-gallium-sulfide (CIGS) and cadmium-tellurium (Cd-Te) have the greatest potential for increasing efficiency. Many manufacturers are pushing ahead with the development of this technology and are offering some of the highest efficiency rates for their models, increasing it by 19%. They achieved this value using several methods, including the use of reflective coatings that can capture more light from the corner.

If we justify the dependence not on the material, but on overall dimensions, then the higher the efficiency, the smaller the required working surface area of ​​the batteries.

Although the average percentage may seem a little low, it is possible to easily change the equipment, precisely at installation, with enough power to cover the energy needs.

Factors affecting the efficiency of solar arrays include:

Mounting Surface Orientation
The roof should ideally face south, but the quality of the design can often compensate for other directions.

Tilt angle
The elevation and slope of a surface can affect the number of hours of sunlight received on an average day throughout the year. Large commercial systems have solar tracking systems that automatically change the angle of the sun's beam throughout the day. Typically not used for residential installations.

Temperature
Most panels become hot during use. Therefore, they usually need to be installed slightly above roof level to ensure sufficient cooling air flow.

Shadow
In principle, shadow is the enemy of solar energy. If a poor mounting design is chosen, even a small amount of shadow on one panel can shut down the energy production of all other elements. Before a system is designed, a detailed shading analysis of the mounting surface is carried out to identify possible shapes shade and sunlight throughout the year. Another detailed analysis is then carried out to test the conclusions reached.

Conventional solar panels with high efficiency industrial-scale solar systems are installed on piles 80 cm above the ground, located in the direction from east to west, along the movement of the sun, at an angle of 25 degrees.

I'm interested in meeting people who are in constant search. Among them is my colleague Alexander, a fan of electric vehicles. You will find information about its developments and the formation of a fleet of electric vehicles in Ukraine here. But, oddly enough, in addition to the electric car, he is also interested in solar panels with high efficiency.

After asking him a question, I had to sweat a little, and this is what came out of it.

Silicon crystalline photomodules

The efficiency of silicon module cells today is about 15 - 20% (polycrystals - single crystals). This figure may soon be increased by several percent. For example, SunTech Power, one of the world's largest manufacturers of crystalline silicon modules, has announced its intention to launch photovoltaic modules with 22% efficiency within two years.

Existing laboratory samples of monocrystalline cells show a productivity of 25%, polycrystalline - 20.5%. The theoretical maximum efficiency of silicon unijunction (p-n) elements is 33.7%. While it has not been achieved, the main task of manufacturers, in addition to increasing the efficiency of cells, is to improve production technology and reduce the cost of photomodules.

Separately positioned are photo modules from Sanyo, produced using HIT (Heterojunction with Intrinsic Thin layer) technology using several layers of silicon, similar to tandem multilayer cells. The efficiency of such elements made of single-crystalline C-Si and several layers of nanocrystalline nc-Si is 23%. This is the highest cell efficiency of serial crystalline modules to date.

Thin Film Solar Cells

Under this name, several different technologies have been developed, the following can be said about their performance.

Today, there are three main types of inorganic film solar cells—amorphous silicon (a-Si) films, cadmium telluride (CdTe) films, and copper indium gallium selenide (CuInGaSe2, or CIGS) films.

The efficiency of modern thin-film solar cells based on amorphous silicon is about 10%, photomodules based on cadmium telluride - 10-11% (manufacturer: First Solar), based on copper-indium-gallium selenide - 12-13% (Japanese solar modules SOLAR FRONTIER) . Efficiency indicators of serial cells: CdTe have an efficiency of 15.7% (MiaSole modules), and CIGS cells produced in Switzerland - 18.7% (EMPA).

The efficiency of individual thin-film solar cells is much higher, for example, data on the performance of laboratory samples of amorphous silicon cells is 12.2% (United Solar), CdTe cells are 17.3% (First Solar), CIGS cells are 20.5% ( ZSW). So far, solar converters based on thin films of amorphous silicon lead in production volumes among other thin-film technologies - the global market volume of thin-film Si cells is about 80%, solar cells based on cadmium telluride are about 18% of the market, and copper-indium-gallium selenide is 2% market.

This is due, first of all, to the cost and availability of raw materials, as well as higher stability of characteristics than in multilayer structures. Note that silicon is one of the most common elements in the earth's crust, while indium (CIGS elements) and tellurium (CdTe elements) are scattered and mined in small quantities. In addition, cadmium (CdTe cells) is toxic, although most manufacturers of such solar panels guarantee complete recycling of their products.

Further development of photoelectric converters based on inorganic thin films is associated with the improvement of production technology and stabilization of their parameters.

And yet, based on the stability of characteristics and relatively inexpensive price, preference is given to solar batteries made on the basis of amorphous silicon. But as we see, their efficiency is no more than 12.2%.

Better results have so far been achieved in laboratory conditions. An example is the development of engineers from the Swiss National Laboratory of Materials, Science and Technology EMPA, who managed to achieve a high efficiency rate (20.4%) working with a new generation of thin-film solar panels. The new panels are based on flexible polymers made from the complex compound CIGS or copper indium gallium (di) selenid (copper-indium-gallium-(di) selenide).