Polaris solar PV net news: Abstract: with the development of photovoltaic technology, wider application of photovoltaic power generation, species is also increasing, from traditional PV power station (off-grid or grid-connected) to the building integrated photovoltaic (BIPV), PV-LED, and so on. In these applications, the vast majority of used rigid solar cells, such as crystalline silicon cells. Rigid battery is not capable of and in some occasions, flexible solar cell with its unique, flexible features and won a place at various outdoor portable applications, in particular the scientific, military, and plays an irreplaceable role. This paper now more mature, more widely flexible amorphous silicon solar cells, and introduces the features of flexible solar cells, different from traditional batteries, preparation method and portable power supply system, and also describes a portable solar power system configuration, how to best in cost control and produce the best results, provide a reference for more detailed design in the future. With the development of technology, and will also have more flexible solar cells have been developed to form products, we also will provide the next generation of flexible solar cells of the future trend is introduced and discussed.
Key words: flexible solar power, portable power supply battery
1, flexible solar cells
In the above types of solar cells, most of the rigid structures, which are material for glass, supplemented by tightening of the border. We can imagine, saddled with a huge glass panels in the open air, and how unpleasant it is. Although some varieties can be prepared into a flexible shape, flexibility and destructive resistance, weather resistance and life are a lot of shortcomings. Of flexible silicon products such as SUNPOWER Corporation, have been able to achieve a minor fault can still continue to work, but flexible level reached only 30%, that is to say, when you bend to 31%, the battery will completely breaks off and scrapped.
Paper outdoor flexible portable solar power systems, solar cells are the core content. For outdoor use, it is difficult to restrict a user to a variety of uses, especially in the military field, a weak battery, is incapable of “portability” of these three words.
Although CdTe, CIGS cells become damaged solar modules can be prepared, but they still did not solve the problems of oxygen water, life is quite limited. In recent years, China’s sweep of the Hina group American CIGS companies, acquired a number of heavyweight CIGS makers, ready to rumble. While they were on the roof power (BIPV) create a lot, but still flexible solar cell was slow to launch products, mainly caused by packaging process plagued by water.
Organic solar cells are flexible solar cells is an important direction in the future, he used the printing production, high efficiency and low cost, not only in the future can be prepared into a flexible, can even be used as coatings applied directly. However, as frontier laboratories or companies around the world stand now can only remain in the glove box + glass device stage, the road is very long.
Truly successful commercial application, only a flexible amorphous silicon solar cells.
2, flexible amorphous silicon solar cells
Since 1945, United States the Bell telephone laboratories produced the world’s first practical silicon solar cell start will usher in a new era of modern humans using solar energy. Along with vigorously research all over the world for decades, and the exploitation of solar energy in the ascendant in recent years, the solar developed an endless stream of new products, including flexible amorphous silicon solar cells is one of most brilliant star.
2.1 flexible form of amorphous silicon solar cells

Flexible soft, transparent, thin amorphous silicon solar cell (approximately 1 μm thickness), original of solar PV modules (see figure II) lamellar, and its mass production manufacturing technology has fully matured, Silicon required for each KW only 0.067 kg, and its high-frequency spectra of sunshine (blue) are most sensitive.
Flexible thin-film solar cells in addition to traditional solar photovoltaic conversion function, as its name suggests, its soft light, packaged (solar cells to be encapsulated is inaccessible to normal use) thickness of only 1.5mm, the output power of 50W solar panels weigh only 2.5KG, is the traditional one-sixth of solar energy. Surface abandoned due to its brittle, fragile glass or resin material with high molecular weight polymer adhesive film package, making the product more flexible and durable, and can be arbitrary curved folding (conventional solar cells are encapsulated glass and fragile), and can be made into any shape according to the different equipment requirements when folded only book size, easy to carry. When field work, just any spreading or hanging solar panels, it can power the load, and carried on walking.

No influence of temperature: solar products in General when used outdoors, inside solar cells (SolarCell) temperature is not affected
Light quality: 7.0kg/m?, not because the laying of panels for roof overburden load, roof structure of the selection will not be big changes occurred because the laying of panels.
Flexible, easy to bend: thin-film panels are lightweight software materials on roofs, an average slope of <60 ° and >13m arbitrary shapes can be roof when the bending radius bends.
Durable: the use of UV-resistant polymer encapsulated solar cells, so the products are particularly durable, clean, smooth surface, do not vacuum any dirt can be washed when it rains. Roof without the need for external cleaning.
Cover image: products by three storey Volt electro-optical technique, when it comes to shielding or shading occurs, will still be able to convert the output more power than solar energy products.
No glass: abandon the whole fragile glass instead of the DuPont product (DuPont) polymer to protect the solar cells.
2.2 bypass Diode technology
Used to be obscured when the Sun’s rays are still offers higher conversion rates-bypass Diode technology. When the solar panels when partially obscured by surrounding buildings or roof above the object, due to the bypass diodes connected merely shadows covered part of solar panels do not participate in the work, and the rest is still working correctly, which is shaded in this group generates a current. And polysilicon panels as soon as a shaded, full set of solar panels will quit working.

2.3 the spectral absorption range
Flexible have three layers of amorphous silicon solar cells embedded in a Silicon Crystal, attached to the stainless steel film, covered with polymer of ethylene vinyl acetate (EVA) protective layer. Three-layer membrane adhesion may be thinning each electron shell thickness, so each child cells of the inner electric field increases, increased collection efficiency of the battery, extended spectral range. Each layer Silicon Crystal are can conversion visible spectrum in the of specific part, thus even in rainy, and cloudy weather in the also can provides high of photoelectric conversion rate, cover has non-crystal silicon relative Yu polysilicon, Silicon Board in fine weather conversion rate low of insufficient (crystal silicon battery conversion efficiency in 17% around, non-crystal silicon battery about for 8-10%, conversion efficiency high main reflected in products can save must by light area, and general power not variable).

Figure d the spectral absorption range
2.4 design of three-layer structure
In conventional amorphous silicon cells, divided into single, tandem, triple, and even has no less than 5 knots. But the costs taken into account, more commonly used are 3 junctions. So-called 3 knot structure is divided into three layers-layers, the absorption of solar spectral region. He P.I.N integrated multilayer manufacturing to reduce light reflection effect, and P.I.N is mainly conducting layer, composed of amorphous germanium materials and structures, make band-gap characteristics to reconcile energy conversion rate of up to 8.6% per cent. Electric field ranging from x-ray radiation solar spectrum and class codes radiation its wavelength:
Ultraviolet radiation (0.04-400nm) 9%
Visible light waves (400-700nm) 47%
Infrared waves (700-300,000) 44%
Such as microwaves and radio waves.
Crystalline silicon solar cell to red Visual spectral bands (such as the winter sunlight spectrum) absorption maximum, in the clear air under bright sunshine duration density up to 1100-1250W/m2. A-Si amorphous solar cell materials, blue sunlight spectrum (such as summer and the cloudy circumstances) the absorption effect in Sunshine only 50-400W/m2 climates are able to get the highest conversion efficiency of light energy.
Crystalline silicon solar cell to red Visual spectral bands (such as the winter sunlight spectrum) absorption maximum, in the clear air under bright sunshine duration density up to 1100-1250W/m2. A-Si amorphous solar cell materials, blue sunlight spectrum (such as summer and the cloudy circumstances) the absorption effect in Sunshine only 50-400W/m2 climates are able to get the highest conversion efficiency of light energy.

⑸ three composite layers
Structure design of three composite solar sandwich, Pu layer absorbs all the wavelengths of the sun light, so it can be converted and output more power than solar energy products.
Using amorphous silicon top layer materials, optical energy gap 1.8eV, conducive to the absorption of blue light.
Underlying the use of amorphous silicon-germanium alloy material with pass, the optical energy gap of 1.4eV that can absorb red light and far red light.
Middle kick and amorphous silicon germanium alloys, optical energy gap 1.6eV, conducive to absorbing green light.
Is not absorbed when light enters the light may be the basal layer of silver and zinc oxide (Ag/Zno) reflect back, reflection on the way out and absorbed. )
2.5 environmental and climate impact
Due to seasonal and year round sunshine density as temperature changes, timing of solar density of sunshine, cloud cover and temperature (heating) effect, solar cell efficiency because the product is linked to climate (see chart services, ⑺ curve data data comparison description).
Output energy loss curve comparison chart of temperature rise, polycrystalline silicon photovoltaic modules in the standard full sun (1000W/m2) with 60 ℃ operating temperature situations, its energy (voltage) conversion loss is over 15%, Crystal State solar photovoltaic modules of approximately 17%.
Flexible amorphous silicon solar cells is not affected, and not only on the density of sunshine (600W/m2) energy loss apparently unjustified, so under the seasonal climate in East Asia, its energy output had risen in. Therefore solar PV module energy conversion rate, direct materials and structures technology and regional seasonal climate temperature are closely related.

⑹ 25 c and 60 c amorphous silicon and crystalline silicon efficiency comparison

⑺ 25 c and 60 c amorphous silicon and crystalline silicon to produce electricity comparison
2.6 package features
Flexible amorphous silicon solar cell surface mount a scientific design of the polymer adhesive film, its surface texture can absorb the light from every angle, effectively preventing the sunlight loss. Rainy days even in the absence of sunlight, it can also generate about 30% power, overall efficiency than conventional solar cells 20%.
Not only that, flexible thin-film solar cell by encapsulation with a maintenance-free, waterproof, corrosion resistance, stain resistance, impact resistance, resistance to stress, temperature insulation and other conventional solar don’t have advantages. Its surface using high strength inert fluorine plastic film packaging, smooth surface does not adsorb, even if contaminated, can also be washed by the rain or easy cleaner to remove dirt. TP-SOLAR flexible thin-film solar cells to 80 ℃-40 ℃ environment can work, even if some areas penetrated by a bullet, with the rest still are not subject to the effects of electricity.

(8) with camouflage cloth package-flexible amorphous silicon solar module

(9) a flexible amorphous silicon solar module after you expand and collapse shape
2.7 service life
Single on flexible non-crystal silicon solar for, its using life is long, package PV Board power system 20 years within has 80% of power output guarantee, (because PV Board in 15 years Hou will stop degradation, thereafter PV Board still can produced not less than 20% of power), 20 years Hou whole PV Board system also can using long main rely on Yu buildings by at of climate environment. Controllers, inverters, electronic equipment, are often only 5-year life span, after 5 years need to replace some parts to make it work properly, such as cars or electrical appliances need to replace certain parts without a lot of cost. According to the United States outdoor systems of renewable energy laboratory test report: attenuation rate of -0.74% (TP-SOLAR).
3, flexible amorphous silicon solar cells in contrast to conventional solar cells
Evaluate the pros and cons of a solar power generation system in addition to see whether it had even higher photoelectric conversion efficiency, reference should be made to the efficiency of the system during the day. Currently, the supply of monocrystalline silicon solar cell conversion efficiency of 17%, polycrystalline silicon 16%, amorphous silicon solar cell conversion efficiency is only 9%, but this does not mean that crystalline silicon solar cell than amorphous silicon solar cell during the day will be more light energy into electrical energy. Because of the different characteristics of the material itself, amorphous silicon solar panels has the advantage of crystalline silicon solar cells can not match. Monocrystalline silicon solar cells generally only at noon on a sunny day, have a photoelectric conversion capabilities, than monocrystalline silicon, polycrystalline silicon and amorphous silicon solar cell a solar cell module has a longer generation times, whether it is sunny or irradiated by high intensity in dust, rainy days of weak scattering light, amorphous silicon solar panels is greater than the power generating capacity of monocrystalline silicon solar cells with power generating capacity. Throughout the year under a changed climate, amorphous silicon solar panel power generation efficiency than monocrystalline silicon solar panels.


Text/aronakira Xiamen University’s School of physics and electrical and Mechanical Services (Xiamen Han Qing information technology company)
Wang Yajun, an associate professor of Xiamen University, school of physics and electrical engineering
Jia Yingchun Chen Yanling zhouzhenfuguojie
Original title: research on flexible properties of amorphous silicon solar cells