Silicon Solar Cell Arrays Research Articles

Receiving energy analysis and optimal design of crystalline silicon solar cell array on solar airship

The energy of solar airships comes from solar array, and the amount of solar radiation received by solar array determines airship endurance. Many studies optimize the solar array layout to receive more solar radiation. However, most of them are for flexible thin-film array. The influence of the size of the currently commonly used crystalline silicon panels on received energy is not considered. This paper establishes a solar irradiation model and a receiving energy model suitable for crystalline silicon arrays. The effects of array shape, array location, and module size on the energy received by crystalline silicon solar arrays are analyzed at different flight latitudes. Then, an improved genetic algorithm is designed to optimize the array geometric parameters. The results show that altering the size and layout of solar modules significantly influences energy capture, with opposing trends between regions of mid-low latitudes and high latitudes. Airships flying at mid-low latitudes should adopt larger solar modules, while airships flying at high latitudes should adopt smaller ones. After the optimization using the proposed algorithm, the received energy of solar array is further enhanced. The optimization resulted in a 2% improvement at mid-low latitudes and an 18% improvement at high latitudes over conventional optimization.

Laser direct writing based flexible solar energy harvester

With the rapid advancement of flexible electronics, conventional rigid batteries, which serve as energy devices for flexible electronics, are no longer capable of meeting developmental requirements. In this context, solar cells, as an eco-friendly, low-carbon, and sustainable energy technology, have gained significant recognition. This paper aims to design a flexible solar energy harvester (FSEH) based on laser direct writing. The FSEH is comprised of commercial PET/PI films, flexible Cu circuits, and amorphous silicon solar cells which provide excellent flexibility and sustainability. The FSEH was formed by soldering the solar collection array to the laser direct-written flexible Cu circuit by using solder paste. The solar energy harvesting array consists of six sets of series-connected amorphous silicon solar cell arrays, with each set comprised of six amorphous silicon solar cells connected in parallel. It has a maximum light collection area of about 2772 mm2. The designed FSEH could generate energy by harvesting light energy from lights or solar radiation. The FSEH outputs 0.437 mW at the light intensity of 3000 Lux and 1.813 mW at the light intensity of 10,000 Lux. The FSEH maintains an output efficiency of over 92% with a bending angle of less than 45°. Based on laser direct writing technology which enables efficient, convenient, and large-scale production of FSEH, the FSEH is expected to form a flexible self-powered system with flexible supercapacitors and wearable electronics, and FSEH offers great advantages for the sustainable development of wearable electronics and flexible sensors.

Antireflection and radiative cooling difunctional coating design for silicon solar cells.

Passive daytime radiative cooling (PDRC) as a zero-energy consumption cooling method has broad application potential. Common commercial crystalline silicon (c-Si) solar cell arrays suffer working efficiency loss due to the incident light loss and overheating. In this work, a radiative cooler with PDMS (polydimethylsiloxane) film and embedded SiO2 microparticles was proposed to use in silicon solar cells. Both anti-reflection and radiative cooling performance can be improved through numerical parametric study. For the best performing of PDMS/SiO2 radiative cooler, the thickness of PDMS layer, volume fraction and radius of the embedded SiO2 particles have been determined as 55 µm, 8% and 500 nm, respectively. 94% of emissivity in first atmospheric window band (8-13 µm) for radiative cooling and 93.4% of solar transmittance at the crystalline silicon absorption band (0.3-1.1 µm) were achieved. We estimated that the PDMS/SiO2 radiative cooler can lower the temperature of a bare c-Si solar cell by 9.5°C, which can avoid 4.28% of efficiency loss. More incident light can enter and be utilized by silicon layer to enhance the efficiency of the solar cells. The proposed difunctional radiative cooling coating may become guidance for next generation encapsulation of crystalline silicon solar cells.

Performance study of solar cell arrays based on a Trough Concentrating Photovoltaic/Thermal system

The performances of solar cell arrays based on a Trough Concentrating Photovoltaic/Thermal (TCPV/T) system have been studied via both experiment and theoretical calculation. The I– V characteristics of the solar cell arrays and the output performances of the TCPV/T system demonstrated that among the investigated four types of solar cell arrays, the triple junction GaAs cells possessed good performance characteristics and the polysilicon cells exhibited poor performance characteristics under concentrating conditions. The optimum concentration ratios for the single crystalline silicon cell, the Super cells and the GaAs cells were also studied by experiments. The optimum concentration ratios for the single crystalline silicon cells and Super cells were 4.23 and 8.46 respectively, and the triple junction GaAs cells could work well at higher concentration ratio. Besides, some theoretical calculations and experiments were performed to explore the influences of the series resistances and the working temperature. When the series resistances R s changed from 0 Ω to 1 Ω, the maximum power P m of the single crystalline silicon, the polycrystalline silicon, the Super cell and the GaAs cell arrays decreased by 67.78%, 74.93%, 77.30% and 58.07% respectively. When the cell temperature increased by 1 K, the short circuit current of the four types of solar cell arrays decreased by 0.11818 A, 0.05364 A, 0.01387 A and 0.00215 A respectively. The research results demonstrated that the output performance of the solar cell arrays with lower series resistance was better and the working temperature had a negative impact on the current under concentration. In addition, solar irradiation intensity had certain effects on the solar cell’s performance. For the crystalline silicon solar cell arrays, when the solar direct radiation exceeded a certain value, the I– V curves almost became a straight line and the output performances decreased due to the high series resistance leading to the high power loss. For the triple junction GaAs solar cell array, its performance was always excellent.

The performance analysis of the Trough Concentrating Solar Photovoltaic/Thermal system

The electrical and thermal performance of a 2 m 2 Trough Concentrating Photovoltaic/Thermal (TCPV/T) system with an energy flux ratio 10.27 are characterized by experiments. A single crystalline silicon solar cell array, a polycrystalline silicon cell array, a Super cell array and a GaAs cell array are respectively used in the experiments. The experimental results show that the electrical performance of the system with the GaAs cell array is better than that of crystal silicon solar cell arrays. The superior output performance of the GaAs cell array mainly benefits from its lower series resistance. But the thermal performances of the system using the single crystal silicon solar cell array and the polycrystalline silicon solar cell array are better. It results from the widths of the two types of cells in the system close to that of the focal line. Another 10 m 2 TCPV/T system with an energy flux ratio of 20 using the GaAs cell array and a concentrating silicon cell array are also constructed and characterized. The experimental results indicate that the photoelectric efficiency of the GaAs cell array is 23.83%, and the instantaneous electrical efficiency and thermal efficiency of the system are 9.88% and 49.84% respectively. While the instantaneous electrical efficiency and thermal efficiency of the system using the low-cost concentrating silicon cell array are 7.51% and 42.4% respectively. The economic performance analysis show the electricity generating cost of the TCPV/T system with the concentrating silicon cell array can catch up with flat-plate PV system, but besides electricity generation, the TCPV/T system supplies extra heat energy to users.

Performance analysis of solar cell arrays in concentrating light intensity

Performance of concentrating photovoltaic/thermal system is researched by experiment and simulation calculation. The results show that the I–V curve of the GaAs cell array is better than that of crystal silicon solar cell arrays and the exergy produced by 9.51% electrical efficiency of the GaAs solar cell array can reach 68.93% of the photovoltaic/thermal system. So improving the efficiency of solar cell arrays can introduce more exergy and the system value can be upgraded. At the same time, affecting factors of solar cell arrays such as series resistance, temperature and solar irradiance also have been analyzed. The output performance of a solar cell array with lower series resistance is better and the working temperature has a negative impact on the voltage in concentrating light intensity. The output power has a −20 W/V coefficient and so cooling fluid must be used. Both heat energy and electrical power are then obtained with a solar trough concentrating photovoltaic/thermal system.

The effect of concentrated light intensity on output performance of solar cell arrays

Detailed analysis on the output characteristic and power influence factors of crystal silicon solar cell arrays and GaAs cell arrays have been done based on trough concentrating photovoltaic/thermal system. The results show that under concentrated light intensity, the output performance of GaAs cell array is better than crystal silicon solar cell arrays. Band-gap of solar cell arrays narrows and short circuit current increases very much in concentrated light intensity, which are good for output power. But open circuit voltage of cells drops a little for high recombination rate in depletion region produced by high light intensity, which has a restrictive effect to output power. At the same time the series resistance of cell arrays increases and working temperature of cell arrays rises which are brought about by high concentrated light intensity. In high concentrated light intensity, series resistance of cell arrays hugely affect the output power. When series resistance increases from 0 Ω to 1 Ω, the out put power of four cell arrays respectively drop by 6778%, 7493%, 7730% and 5801%.

Solar cells on curtains

Crystalline silicon solar cell arrays on flexible, transparent substrates may lead to unconventional new applications.

A miniaturized high-voltage solar cell array as an electrostatic MEMS power supply

A hydrogenated amorphous silicon (a-Si:H) solar cell array that is designed as an on-board power source for electrostatic microelectromechanical systems (MEMS) is presented. A single cell consists of a triple layer of p-i-n/p-i-n/p-i-n a-Si:H and produces an open circuit voltage (V/sub OC/) of 1.8/spl sim/2.3 V, a short circuit current density (J/sub SC/) of 2.8 mA/cm/sup 2/, and fill factor (FF) of 0.495. A series interconnected array of 100 single solar cells (total array area of 1 cm/sup 2/) is fabricated in an integrated fashion and produces an array V/sub OC/ of 150 V, and array short circuit current (I/sub SC/) of 2.8 /spl mu/A under Air Mass (AM) 1.5 illumination. To demonstrate the usefulness of this solar cell array as an on-board power source for electrostatically driven micromachined devices, it has been packaged with a movable micromachined silicon (Si) mirror in a hybrid manner. The movable Si mirror is directly driven by the cell array electrical output, and the motion of the mirror plate has been observed reproducibly. Variation of light intensity and/or number of illuminated cells produces different values of array V/sub OC/, thus enabling control of the deflection of the Si mirror by variation of incident light intensity. >

Present status and future prospects of silicon solar cell arrays and systems

The first part of this paper deals with the present state of the art of the single crystal silicon cell industry: production volume, cost breakdown and main technologies. In the second section, improvements of the single crystal technologies, caused by mass production and automated physical processes, are described. These developments are compared, with regard to both cost and performance, with the future polycrystalline (or ‘semicrystalline’) materials, including amorphous silicon films. The various approaches, i.e. vapour or liquid film deposition, or oriented bulk ingot crystallization, are discussed. The third part assumes that very low cost goals can be achieved, either through the development of sophisticated single crystal technology, or through a polysilicon breakthrough. Future markets for photovoltaic conversion, including medium-size power generating plants, are then considered.

Solar Thermoelectric Power Generation for Mercury Orbiter Missions

Mercury orbiter mission study results have shown that conventional silicon solar cell array technology is not adequate to produce power because of expected temperatures which range from - 90°C to + 285°C in about 50 min for 16 sun eclipses per day. The solar thermoelectric generator (STG), which requires relatively high temperatures, is being developed as a replacement power source. Several thermoelectric technologies (i.e., lead telluride alloys, bismuth telluride, copper and gadolynium selenide, and silicon-germanium alloys) have been examined for their suitability. Solar concentrator configurations (i.e., flat plate, Fresnel lens, compound parabolic, and Cassegrain types) were also studied as candidates for increasing incident radiation during Mercury orbital operations. Detailed results are presented, and show that an STG design based on the use of silicon-germanium alloy thermoelectric material and using high-voltage thermopiles with individual minicompound parabolic concentrators presents the optimum combination of technology and configuration for minimizing power source mass.

Structural Failures in Light-weight Solar Cell Arrays under Thermal Cycling

Several different types of small silicon solar cell arrays mounted on lightweight honeycomb panels and on flexible substrates were subjected to long-term thermal cycling tests between -160 and 600C in dry nitrogen. Other tests included immersion in liquid nitrogen and vibration fatigue tests in excess of one million cycles. The arrays experienced a reduction in output caused by contact failure, fracture in the silicon and cover slide, and disintegration of the honeycomb. Failure modes caused by different cell and interconnect constructions are compared.

Ultra reliable submerged repeaters : W. J. Archibald, Electron. Equip. News. February (1968), p. 46

Although still expensive, silicon solar cell arrays are becoming increasingly common for some specialised remote area applications. Within Australia solar photovoltaic generators are being used to provide power for microwave radio repeater stations, VHF subscriber radiotelephone systems, UHF small capacity radio systems, as well as many other professional and commercial applications. In all of this plant it is vital to be able to provide reliable low maintenance primary power. A new generation of low power consumption communication equipment has made it possible to completely power broadband radio relay repeaters using only the solar source with power storage being provided by storage batteries of the pure-lead positive pasted-plate type. Several years of operational experience in remote locations have now been obtained with this solar generating equipment.