scholarly journals Using a layer based on materials with a metal to semiconductor phase transition for electrothermal protection of solar cells

2021 ◽  
pp. 57-64
Author(s):  
A. S. Tonkoshkur ◽  
A. V. Ivanchenko
Keyword(s):  
Phase Transition ◽  
Solar Cells ◽  
Voltage Drop ◽  
Thermal Contact ◽  
Electrical Power ◽  
Photovoltaic Cells ◽  
Photovoltaic Cell ◽  
Power Sources ◽  
Solar Arrays ◽  
Local Overheating

One of the main problems in ensuring the reliability of solar electrical power sources is local overheating, when hot spots form in photovoltaic cells of solar arrays. It is currently considered that these negative phenomena are caused, among other things, by overvoltage in the electrical circuits of solar arrays. This leads to the appearance of defective elements and a significant decrease in the functionality of the entire power generation system up to its complete failure. This study considers the possible ways to increase the reliability of solar arrays by using thermistor thermocontacting layers for preventing overvoltage events and overheating. The authors use simulation to study electrical characteristics of a photovoltaic cell in thermal contact with an additional layer based on thermistor materials with a metal to semiconductor phase transition. Vanadium dioxide with a phase transition temperature of ~340 K is considered to be a promising material for this purpose. During the phase transition, electrical resistance sharply decreases from the values characteristic of dielectrics to the values associated with metal conductors. It is shown that such thermistor layers can be used for protecting solar cells from electrical overheating under the following basic conditions: — the layer’s resistance in the «cold» state significantly exceeds that of the lightened forward-biased solar cell; — the layer’s resistance in the «heated» state is sufficiently low compared to those of the reverse-biased photovoltaic cell and of the power source. The current and temperature of the reverse-biased photovoltaic cell are limited and stabilized, and the voltage drop sharply decreases from the moment when the temperature of the thermistor layer reaches the values close to the temperature of its transition to the low-conductivity state. The obtained results substantiate the potntial of the described approach to protect photovoltaic cells of solar modules against electric thermal overloads.

scholarly journals APPLICATION OF POLYMER POSISTOR NANOCOMPOSITES IN SYSTEMS FOR PROTECTING PHOTOVOLTAIC COMPONENTS OF SOLAR ARRAYS FROM ELECTRICAL OVERLOADS

2021 ◽  
Author(s):  
Alexander Tonkoshkur ◽  
Alexander Ivanchenko ◽  
Liliya Nakashydze ◽  
Alexander Lyashkov ◽  
Igor Gomilko
Keyword(s):  
Polymer Composites ◽  
Thermal Contact ◽  
Photovoltaic Cells ◽  
Operating Time ◽  
Polymer Nanocomposite ◽  
Photovoltaic Cell ◽  
Solar Array ◽  
Photovoltaic Module ◽  
Positive Temperature ◽  
Solar Arrays

The experience of operating solar arrays indicates the need to solve the problem of creating effective and reliable switching elements to block defective and damaged photovoltaic cells. Available methods of solving this problem (for example, the use of transistor switches, electronic systems, etc.) either do not completely solve it, or are expensive. The tasks of increasing the reliability and efficiency of switching elements, preventing the destruction of photovoltaic cells which occurs during heating by dark current ("hot spots" and fire hazardous situations) are relevant. Recently, one of the promising solutions of this problem is the use of additional devices for isolating inactive (shaded or defective) areas of both separate photovoltaic cells and their modules. These devices are PPTC (polymeric positive temperature coefficient) resettable fuses of PolySwitch type, which are polymer composites with nanoscale carbon fillers. The basic functional property of PPTC fuse is an abrupt increase in electrical resistance by several orders of magnitude when a temperature is reached and a return to the initial high conductive state when the temperature drops. The advantages of such structures based on polymer composites with nanocarbon fillers include: – close to the metal resistance to the switching temperature and to the resistance of the insulator above the specified temperature; – possibility of realization in the form of discrete elements and continuous film-tapes (that is important at the decision of problems of realization of isolation of defective local area of the separate photovoltaic cell); – reaction in the form of temporary isolation of separate components of the solar array to increase their temperature. The research results are presented and the concept of overload protection by using resettable fuses based on polymer nanocomposite materials with nanocarbon fillers is substantiated in this paper. In particular, the expediency of series connection of PolySwitch fuses to photovoltaic modules with parallel connection of their strings is shown to prevent an abnormal situation, namely, a complete loss of electrical energy generated by such a string, which can occur when one of its modules is short-circuited. The circuit solutions in the form of combined structure based on layers of a varistor ceramics and a posistor polymer nanocomposite with carbon filler being in thermal contact are investigated. The prospect of its use to protect photovoltaic cells with a high reverse resistance from overvoltage is established. The problem of protection against local overheating in photovoltaic cells (or their parallel connections) by physical and technological methods, in particular, by creating photovoltaic cells with a built-in layer based on a posistor composite being in thermal contact with it, is analyzed. In general, the described results represent a new direction in the field of improving photovoltaic systems, in particular, in terms of increasing their efficiency, operating time and reliability by using solid-state devices based on polymer posistor nanocomposites and varistor ceramics as means of their protection from electrical and thermal overloads. Keywords: SOLAR ARRAY, PHOTOVOLTAIC MODULE, PHOTOVOLTAIC CELL, ELECTRIC OVERLOAD, POLYMER POSISTOR NANOCOMPOSITE, HOT SPOT, VARISTOR CERAMICS

scholarly journals Recent Studies of Semitransparent Solar Cells

Coatings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 329 ◽  
Author(s):  
Dong Shin ◽  
Suk-Ho Choi
Keyword(s):  
Optical Properties ◽  
Solar Cells ◽  
High Performance ◽  
Recent Progress ◽  
Cell Structure ◽  
Photovoltaic Cells ◽  
Perovskite Solar Cells ◽  
Photovoltaic Cell ◽  
Visual Comfort ◽  
Electrical And Optical Properties

It is necessary to develop semitransparent photovoltaic cell for increasing the energy density from sunlight, useful for harvesting solar energy through the windows and roofs of buildings and vehicles. Current semitransparent photovoltaics are mostly based on Si, but it is difficult to adjust the color transmitted through Si cells intrinsically for enhancing the visual comfort for human. Recent intensive studies on translucent polymer- and perovskite-based photovoltaic cells offer considerable opportunities to escape from Si-oriented photovoltaics because their electrical and optical properties can be easily controlled by adjusting the material composition. Here, we review recent progress in materials fabrication, design of cell structure, and device engineering/characterization for high-performance/semitransparent organic and perovskite solar cells, and discuss major problems to overcome for commercialization of these solar cells.

scholarly journals Potential of Betanin Natural Dye for Solar Cells Application

2020 ◽  
Author(s):  
Naoufel Ben Hamadi
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Low Cost ◽  
Photovoltaic Effect ◽  
Photovoltaic Cells ◽  
Dye Sensitized Solar Cells ◽  
Emission Spectra ◽  
Photovoltaic Cell ◽  
Main Body ◽  
Photovoltaic Properties

Abstract Background: A photovoltaic cell, or solar cell, is an electronic component which, exposed to light, produces electricity thanks to the photovoltaic effect. Organic photovoltaic cells are photovoltaic cells of which at least the active layer consists of organic molecules. It has a yield of at least 15%. The future prospects of the research for solar cells application has required for the development in the field.Main body: Dye-sensitized solar cells are considered to be promising candidates for low-cost solar energy harvesting using sustainable and environmentally friendly materials. In general, solar cells sensitized to dyes consist of three parts: TiO2 sensitized to the photoanode dye with porous film on a transparent conductive glass, an electrolyte solution penetrating through the TiO2 anode film, and the conductive oxide transparent platinum glass as counter electrode.Conclusion: In this work, betanin dye was extracted from mature red fruits of Opuntia ficus indica and purified with fractional crystallization protocol using an 8:2 (v/v) ratio of ethyl acetate/ethanol. TiO2_films with different thickness values have been prepared CV and US sensitization of TiO2_films using betanin dye prove an enhancement on the uniformity distribution of the dye on the film in case of US method. Emission spectra of Dye_TiO2 films have been measured and show a hyperchromic shift of the emission intensity with the increase of the thickness due to the augmentation of betanin content. A comparison between the photovoltaic properties of prepared betanin_DSSC and N719 dye_DSSC reveals that betanin dye could be successfully proposed as a sensitizing dye in solar cell applications.

scholarly journals Application of varistor-posistor structure for protection from overvoltages of photovoltaic cells of solar arrays

2019 ◽  
Vol 27 (1) ◽  
pp. 79-88 ◽  
Author(s):  
A. V. Ivanchenko ◽  
A. S. Tonkoshkur ◽  
S. V. Mazurik
Keyword(s):  
Solid State ◽  
Fire Hazard ◽  
Low Cost ◽  
Thermal Contact ◽  
Photovoltaic Cells ◽  
Experimental Studies ◽  
Electric Energy ◽  
Solar Arrays ◽  
In Series ◽  
The Cost

The problems of reducing the cost of ensuring the safe operation of solar cells by using low-cost elements of solid-state electronics to protect against overvoltage photovoltaic cells of solar arrays are considered. The results of experimental studies of the use of a varistor-posistor structure based on a metal oxide varistor and PPTC fuses of the PolySwitch type being in thermal contact to prevent overvoltages in series connections of photovoltaic cells are presented. General schemes for using the considered solid-state structure to limit the indicated constant overvoltages are given and justified. The requirements to the parameters of this structure are determined and experimentally verified. It is shown that such a device makes it possible to limit the long-term constant overvoltages that occur in photovoltaic arrays at the level of photovoltaic cells in the case of their malfunction or shadowing, which can lead to fire hazard and other “abnormal” situations during the operation of solar electric energy sources.

scholarly journals Electroluminescence Test to Investigate the Humidity Effect on Solar Cells Operation

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2659 ◽  
Author(s):  
Daniela Fontani ◽  
Paola Sansoni ◽  
Franco Francini ◽  
Matteo Messeri ◽  
Giacomo Pierucci ◽  
...  
Keyword(s):  
Solar Cells ◽  
Photovoltaic Cells ◽  
Photovoltaic Cell ◽  
Photovoltaic Module ◽  
Climatic Chamber ◽  
Humidity Effect ◽  
Maximum Performance ◽  
Solar Plant ◽  
Drying Treatment

The electroluminescence test is an experiment typically used to verify the behavior of the photovoltaic cell and to qualitatively check its integrity. It works by operating the photovoltaic cell as a diode polarized directly: the cells that light up in a module indicate how many of them work. This test provides an estimate of the maximum performance of the entire photovoltaic module. A qualitative inspection was performed by electroluminescence tests on 48 modules of photovoltaic cells. They had already been installed on a small-size concentration solar plant before the test and some modules had reached a lower level of performance than expected. A first electroluminescence test was performed, which showed that only 61.5% of the photocells worked. Since there were visible signs of humidity within the various modules, some of the inoperative modules underwent a dehumidification treatment in a climatic chamber. A second electroluminescence test showed that the percentage of functioning cells had increased to 66.3% after the drying treatment.

scholarly journals Technique for Outdoor Test on Concentrating Photovoltaic Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Paola Sansoni ◽  
Daniela Fontani ◽  
Franco Francini ◽  
David Jafrancesco ◽  
Giacomo Pierucci ◽  
...  
Keyword(s):  
Electrical Power ◽  
Photovoltaic Cells ◽  
Photovoltaic Cell ◽  
Fresnel Lens ◽  
Solar Exposure ◽  
Direct Exposure ◽  
Current Curve ◽  
Cogeneration System ◽  
Exposure Experiment

Outdoor experimentation of solar cells is essential to maximize their performance and to assess utilization requirements and limits. More generally tests with direct exposure to the sun are useful to understand the behavior of components and new materials for solar applications in real working conditions. Insolation and ambient factors are uncontrollable but can be monitored to know the environmental situation of the solar exposure experiment. A parallel characterization of the photocells can be performed in laboratory under controllable and reproducible conditions. A methodology to execute solar exposure tests is proposed and practically applied on photovoltaic cells for a solar cogeneration system. The cells are measured with concentrated solar light obtained utilizing a large Fresnel lens mounted on a sun tracker. Outdoor measurements monitor the effects of the exposure of two multijunction photovoltaic cells to focused sunlight. The main result is the continuous acquisition of theV-I(voltage-current) curve for the cells in different conditions of solar concentration and temperature of exercise to assess their behavior. The research investigates electrical power extracted, efficiency, temperatures reached, and possible damages of the photovoltaic cell.

scholarly journals Electrical properties of photogalvanic element with built-in posistor layer based on polymer nanocomposite with carbon filler

2020 ◽  
pp. 30-36
Author(s):  
A. V. Ivanchenko ◽  
A. S. Tonkoshkur
Keyword(s):  
Thermal Contact ◽  
Photovoltaic Cells ◽  
Polymer Nanocomposite ◽  
Photovoltaic Cell ◽  
Reverse Direction ◽  
Thermal Breakdown ◽  
Reverse Voltage ◽  
Crystal Silicon ◽  
Carbon Filler ◽  
Current Value

The study considers the problem of preventing overheat and thermal breakdown of a photovoltaic cell when a high reverse voltage is applied to its p—n junction. The overvoltage protection ability of a structure made up of a photovoltaic cell in direct thermal contact with a built-in posistor layer has been experimentally studied. Fragments of solar cells based on single-crystal silicon were used as a photovoltaic cells. The posistor layer was a polymer nanocomposite with carbon filler used in the resettable fuses of the “PolySwitch” technology. The authors study kinetics of changes in the electrical characteristics of such a structure under constant electric overvoltage on a shaded photovoltaic cell, when its p—n junction is turned on in the reverse direction. It is shown that the current and reverse voltage on the shaded photovoltaic cell are limited and reduced from the moment when the temperature of this structure reaches the values close to the temperature of the phase transition of the posistor nanocomposite to the low-conductive state, which is ≈ 125°С. With an increase in the overvoltage value, a decrease in the response time of the considered protection and an increase in the maximum current value through the structure under study are observed. A decrease in the current value required to reach the tripping temperature by the posistor layer can be achieved by reducing the thermal resistance of the contact between the photovoltaic and posistor elements of the structure. The results obtained indicate the possibility of implementing protection against reverse electrical overvoltage and thermal breakdown of photovoltaic systems based on photovoltaic cells with built-in fuse layers of a specified type.

scholarly journals Changes in the characteristics of silicon photovoltaic cells of solar arrays after current overloads

2019 ◽  
pp. 19-25 ◽  
Author(s):  
A. V. Ivanchenko ◽  
A. S. Tonkoshkur
Keyword(s):  
Short Circuit ◽  
Photovoltaic Cells ◽  
Short Circuit Current ◽  
Photovoltaic Cell ◽  
Open Circuit ◽  
Time Range ◽  
Electrical Parameters ◽  
Solar Arrays ◽  
Current Voltage ◽  
Recent Emergence

Recently, much attention has been paid to the study of the influence of current overloads and local overheating on the degradation of the electrical characteristics of the photovoltaic components of solar arrays. First of all, it is connected with the tasks of increasing the reliability and durability of the operation of such renewable sources of electrical energy. Such studies are of particular interest due to the recent emergence of new methods and devices for improving the reliability of solar arrays by isolating inactive (defective or shaded) areas of their photovoltaic components (photovoltaic cells and photovoltaic modules). This paper presents the research results on the influence of current overloads on the current-voltage and volt-watt characteristics and the electrical parameters of photovoltaic cells of solar arrays based on monocrystalline silicon. The testing was performed using the cyclic current overload mode, which is the flow of electric breakdown current passed through the back-turned diode of a photovoltaic cell for several seconds. After that, the photovoltaic cell was cooled to room temperature, and then its current-voltage and volt-watt characteristics were measured. The degradation (decrease) of all the basic electrical parameters of photovoltaic cells (open-circuit voltage, short-circuit current, filling factor of the current-voltage characteristic, and maximum power) has been established. The additive nature of the changes and the average relative decrease of the indicated electrical parameters for one breakdown cycle are determined. Comparison of the response time range of the PolySwitch fuses with the breakdown durations of photovoltaic cells is performed. The conclusion is drawn about the prospect of using such resettable fuses as protection in emergency situations that are associated with current overloads in solar arrays.

scholarly journals Analysis of temperature distribution in a solar element with posistor layer in the presence of local electric heat source

2020 ◽  
Vol 28 (2) ◽  
pp. 95-100
Author(s):  
A. S. Tonkoshkur ◽  
A. V. Ivanchenko
Keyword(s):  
Temperature Distribution ◽  
Thermal Protection ◽  
Thermal Contact ◽  
Cell Plate ◽  
Photovoltaic Cell ◽  
Time Interval ◽  
Solar Photovoltaic ◽  
Local Overheating ◽  
Voltage Drops ◽  
Electric Heat

The temperature distribution in a model structure in the form of a solar photovoltaic cell plate with an additional posistor layer based on a polymer matrix with nanocarbon fillers being in thermal contact is determined and investigated in the presence of overvoltages leading to the occurrence of local overheating regions. It is found that the regions of local overheating expand over time and, as a result, they spread over the entire plate of such a structure. The entire structure is heated above the phase transition temperature of the posistor layer for a time interval of the order of several seconds. The posistor layer goes into a low-conductivity state and most of the voltage drops across it. These results substantiate the prospects of using a posistor layer for electrical and thermal protection of solar photovoltaic cells from reverse overvoltages.

Optical and Thermal Analysis for Immersed Cooling of Photovoltaic Cells in a Highly Concentrated Beam

2011 ◽  
Author(s):  
Ahmed Darwish ◽  
Robert F. Boehm
Keyword(s):  
Electrical Power ◽  
Photovoltaic Cells ◽  
Glass Tube ◽  
Front Surface ◽  
Photovoltaic Cell ◽  
Cell Integrity ◽  
Cell Temperature ◽  
Cell Efficiency ◽  
Concentrated Solar Radiation ◽  
Complete Cell

Concentrated solar radiation can be utilized to generate electrical power from photovoltaic cells, but it increases the photovoltaic cell temperature. This can lead to a degradation of the cell efficiency and too high of a temperature can damage the cell integrity. This is particularly important in dish and tower systems where a maximum uniform flux may be difficult to achieve. While a variety of approaches have been used to the keep the cells cool, most are based upon removal of heat from the back (opposite to the incident flux) of the cell. This paper reports on an immersion cooling technique for the cells, where a coolant is circulated over the complete cell including the front surface. An analysis is given where the cells are placed in a cylindrical glass tube where a liquid is circulated. The impacts of the various thermal processes that result from this approach are described here. A comparison is made to limited experimental data.

Sign in / Sign up

Export Citation Format

Share Document