Current solar cell industry, the dominant technology for solar cells crystalline silicon solar cells with monocrystalline silicon and polycrystalline silicon solar cells. After the recent years the development of the solar cell industry, its effectiveness has been greatly improved, costs decreased significantly. Now, a large-scale production of solar cells in monocrystalline silicon, the average yield of photoelectric conversion can be achieved between 16.5 to 17 per cent, while the polycrystalline silicon solar cells, the average yield of photoelectric conversion 15 , 5%. Crystalline silicon chain of solar cell industry, the main problem is a complex process, therefore, would be the cost of solar cells of crystalline silicon a significant reduction would have greater difficulties. By reducing costs, thin-film solar cells gradually showed its competitive advantage.
Thin silicon films for solar cell technology is relatively mature
Currently, a technical viewpoint, the course is the more mature silicon-based thin film solar cells, thin film solar cells, including amorphous silicon cells and thin-film amorphous silicon solar / microcrystalline silicon thin film solar cells stacked pairs in which the amorphous silicon thin film solar cells 80 of the last century has already begun production on a larger mass scale, but later found that the types of batteries, there is phenomenon of light induced by the recession and its effectiveness slowly, if in the last century, 90 years to expand production of solar cells from crystalline silicon, amorphous silicon thin film solar cells represent a growing share of production weak. Until recently, the market for solar energy continues to grow, and the deficit will result in a worsening of silicon materials, in fact intensified silicon thin film solar cell research and development. People’s main objective is to increase efficiency, improve stability, reduce manufacturing costs, the core technology is the use of PECVD (plasma enhanced chemical vapor deposition) technology, amorphous silicon or microcrystalline silicon thin films deposition, the substrate is a glass of low or stainless steel material.
Currently one-efficiency thin film amorphous silicon photoelectric conversion of 6%, led by the light of the decline rate can be controlled to the value of the initial efficiency of about 15%. In other words, just prepare the effectiveness of components of the battery of 8%, after several months of sun after about 6% efficiency, and ultimately stabilize at this value. This feature can be accepted by consumers today. Currently, the cells of newly developed amorphous silicon / microcrystalline silicon solar can double stacked to achieve the stable efficiency of 8.5%, while its light-induced decrease is smaller, but more complicated because of its technology, the industry is low, leading to still higher than the cost high. In fact, research institutions and industry courses are strengthening their study of silicon thin film solar cell technology, large-scale industrialization, the parties have invested heavily in research and development of new products, including the largest semiconductor manufacturer Applied Materials, the U.S. company, Oerlikon companies in Europe, Japan, a Japanese vacuum, the German firm Leybold Vacuum Society, the United States, EPV Company. These companies can provide complete sets of amorphous silicon or amorphous silicon / microcrystalline silicon solar cell manufacturing double-sized to match the production equipment and manufacturing process.
Silicon thin-film batteries investment boom
In the emerging world of silicon thin film batteries boom investment. Research institutions, described the five generations of silicon thin film technology solar cells: the first generation single-junction amorphous silicon cell solar thin-film, the second generation of Si / Si junction of two thin cells solar film, the third generation of amorphous silicon / microcrystalline double junction cells with thin film silicon solar fourth generation of amorphous silicon / amorphous silicon-germanium thin-film dual junction or triple junction solar cell, the fifth generation Si / Si Ge / 3 junction microcrystalline silicon thin film solar cells. Currently in the field of industrialization is still the first two major technical, but the silicon of the third generation-based thin film solar cells will be in 2009 or 2010 in mass production, when the first and Technology second generation can leave the industry.
The technical aspects of the production line in accordance with the main categories SYSTEM FOR DEPOSITION PECVD can be classified into five types of equipment modes: multi-chamber plate PECVD deposition system (EPV, BudaSolar), Serial-column-line Multi room style single-chip system PECVD deposition (vacuum Japan), column Parallel-line-style multi-room single PECVD deposition system (Leybold Vacuum), a grouping of several style single chamber PECVD deposition system (Applied Materials, Inc.), a multi-chip hybrid PECVD deposition system (Oerlikon Corporation).
Currently, each system in the battery manufacturers to build the production line, but the specific mode of production lines that will become a mainstream technology has never been verified.
Note that the supply of raw materials and technologies to prevent the risk of
For mass production of its CIGS thin-cell battery of the film are more efficient, manufacturers have already introduced a number of pilot-scale components, efficiency of 10% or more, should be one of the film cells more ideal thin solar, but the reason for the delay can not enter mass production, mainly because production of repeatability and stability. Because of the battery using the four types of material, and each type of material is also the need to control a specific crystalline phase to achieve the best of the photoelectric effect, it is difficult to control post-film optical and electrical properties, in particular, is difficult in the way of mass production to control how the repeatability and consistency of products, which contain the cells to become the key to development. Another problem is that since the types of raw materials, In and Ga cells belong to rare materials, lower levels of the Earth, which has led to large-scale production in the future, after the supply of raw materials will become a concern. In addition, currently very few manufacturers of this battery can provide complete sets of equipment production line.
For the CdTe cell, its production technology is simple, mainly by magnetron sputtering, or near-spaced sublimation technology, products, repeatability and consistency of very good quality, efficiency of the battery of ‘current 7% to 8%, and may be easier to increase to 10% above. And lower raw material costs, thus making the types of batteries to quickly expand production. But the types of batteries in the market, it has been the argument that the use of cadmium batteries in the types of elements, this element is in material respects the environment, there have been many societies and strength of the market. And in the reserve next Te can also limit the development of such thin film batteries. So, this battery can be a certain size, high prices in the cells of crystalline silicon, high purity silicon material production capacity is not sufficient to play a buffer role, the actual production scale and possession of a significant market share is doubtful. When the silicon thin film batteries to overcome the technological hurdles, high speed, after development, CdTe cell will halt.
Detailed comparison of three types of battery technology thin film and its advantages and disadvantages, which makes thin film batteries investment or research, should focus on examining the following two points:
First, stocks of raw materials. When a solar cell as an alternative energy products, the extent of its application will be huge amazing, it must therefore be considered as raw materials in the land ownership and the process unit battery material use materials. From this point of view, silicon solar cells will eventually become the winning product, the content of silicon in the Earth accounts for 26%, second only to oxygen reserves for second place on the elements of the earth. Therefore, there is no kind of thin-film batteries in the long term can be compared to silicon thin film batteries. In this perspective, it is equally optimistic about solar cells in crystalline silicon. What CIGS or CdTe cells, the reserves of basic raw materials contain enough rare metals, the outlook is not optimistic. Even the new ones like nano-titanium dioxide, dye solar cells are also a consequence of the widespread use of titanium as a rare element which increases the supply of its raw material concerns.
Secondly, the risk of technological progress. Currently a variety of thin film batteries are entering the market to stage a number of factories and research units in the early development of technology and equipment to make enormous financial and human resources so that the new technology, equipment, manufacturing costs and process costs are high, which makes thin film batteries, the high price of production lines, such as the 25MW amorphous silicon thin line battery film production, sold 300 million yuan 4 billion euros, while the 25 MW solar cell silicon crystal production equipment online only costs 40 million yuan to 5,000 yuan, the great difference. Even more critical is the thin film battery current technological advances rapidly, so that Chinese battery manufacturers spend huge sums of money to buy the expensive thin-film cell manufacturing equipment later in a period of time short there emergence of new technologies, so that old equipment may have been eliminated. This makes thin film battery equipment depreciation is affected by high cost thin film cells, solar. There is also the China manufacturer thin film battery technology strength is low, there is no possibility of updates of the thin-film battery technology, technology so new and the advent of new equipment, manufacturers are unable to adapt to technological progress, will face a re-acquisition of new equipment or eliminate situations.
Therefore, the thin-film batteries of the trend of future development, we believe that thin film batteries will be the first in Europe, America and Japan, countries and regions, the large-scale development, while the solar cells crystalline silicon and other technologies mature China and other developing countries.
From the thin batteries with the film side of investment, the most important thing is to hire or self-cultivation of a technical team to ensure that equipment maintenance and future technology updates to play its role.
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Three types of cells in thin film solar mass production
As its name suggests is a layer of thin film batteries will be prepared in the solar cell thin films, which use fewer materials, simple process, energy consumption, which have a certain competitive. Is now able to undertake large-scale production of industrial thin-film batteries are essentially three types: silicon-based thin film solar cells, copper indium selenide Gallium thin film solar cells (CIGS), cadmium telluride cells thin film solar (CdTe).
These three types of thin film batteries have a manufacturer in the world is currently in production on a large scale. Production For example, the United States in 2007 will FirstSolar cadmium telluride thin film solar cells to 207MW expanded to become the world’s fourth largest manufacturer of solar cells, whose production capacity of 300 MW, which makes the world’s fastest growing thin film solar cell company, announced that they cost only U.S. $ 1.47 per watt, much less than the same period the cost of solar cells, crystalline silicon. In the world there were silicon-based thin film plant cells solar manufacturing, whose company UnitedSolar United States, Japan and Mitsubishi Corporation Kenaka, Schott Germany companies have already started production of amorphous silicon thin film Solar cell lines. Japan, Sharp Corporation in 2007, production of solar cells is crystalline silicon in 16% of the fall, the company introduced a new strategy of development of solar cells is to promote vigorously the silicon thin film solar cell construction production lines and production of solar cell industry in crystalline silicon base to China or other countries with lower manufacturing costs for high transfer. Copper indium selenide thin gallium difficulties cells film solar manufacturing due to its larger, there is no real climate of the formation of the solar cell plant, but the number one global society solar cell or R & D units are intensifying their research into a large-scale industrialization of solar cells earliest possible stage production.