In recent years, due to the strong support of domestic policies, the photovoltaic industry has ushered in a full recovery. The industry is moving toward healthy and sustainable development. Photovoltaic companies have also gradually turned from losses to losses. All this comes from the country’s high subsidies for photovoltaic power generation and the development and upgrading of the company’s own technology. Photovoltaic ground power stations are building rapidly, but there are also many ground power stations. There are many problems that need to be solved urgently, for example, there are many hidden dangers in engineering construction. The construction of project projects does not conform to the relevant national standards, and some enterprises with low technology acquire subsidies to seize resources. They have started construction of photovoltaic power plants and have wasted limited resources for safe operation of power plants. Possibility of hidden safety hazards indirectly affects investors' profitability. As a result, the development of the photovoltaic industry faces numerous obstacles. The development of the industry is uneven. After the completion of the construction of the photovoltaic power station, the power generation directly affects the investor’s yield and indirectly affects the capital circulation of a company. The development of the enterprise. Although the proportion of photovoltaic power station construction in China has rapidly increased, the attenuation of power generation by photovoltaic power plants has not attracted much attention. In particular, the power generation of EPC distributed photovoltaic power plants has been attenuated. There are relevant standards for photovoltaic power plants in foreign countries. For EPC, If the attenuation of the power station is large, the contractor will face the risk of claims. As China's domestic PV has just developed, investors in this area, including related photovoltaic technicians, have not received enough attention. The core component of a photovoltaic power station is a photovoltaic module. The quality and attenuation of the photovoltaic module directly affect the total power generation of the photovoltaic power station. Therefore, it is important to discuss the attenuation of the photovoltaic module for the construction of the photovoltaic power station. First, the attenuation is generally divided into photo-induced attenuation and aging attenuation. At present, there is an international proposal for obtaining PID potential energy-induced attenuation that many technical researchers agree with. At present, the former two are discussed more frequently. Photo-attenuation is mainly caused by battery process problems and battery raw materials, which means that the output power of photovoltaic modules in the initial application of a few days will have a sharp decline, but the output power will gradually stabilize. Photo-induced attenuation theory: Light or current injection causes boron in the silicon wafer to combine with oxygen to form a boron-oxygen complex, further reducing the minority carrier lifetime in the wafer, resulting in a decrease in the efficiency of the photovoltaic module. B+2O BO2 has a long life on the left side and reverses on the right side Summary: The higher the boron oxygen component in the silicon wafer, the more boron-oxygen complexes under light or current injection conditions, the more component power attenuation of the composite, the more oxygen, low boron, doping, phosphorous doping, Replacing boron with phosphorous can effectively reduce the attenuation of photovoltaic modules. Photovoltaic module photo-attenuation solution: The content of oxygen and boron in the silicon wafer determines the photo-induced attenuation of the module. Therefore, the lower the boron oxygen in the wafer, the better the quality of the wafer and the lower the amount of light attenuation of the module. . Fundamentally, the photo-induced attenuation of photovoltaic modules starts with silicon wafers: Method 1: Improve the boron-doped p-type Czochralski silicon quality: In China, boron-doped Czochralski silicon is the mainstream product in China's current silicon-gang market. Avoid the use of low-quality polysilicon materials in the production of silicon rods; control the incorporation of excessive low-resistance n-type silicon materials to avoid the production of highly compensated p-type monocrystalline rods, because the high boron oxygen content will lead to the emergence of large photovoltaic components Attenuation of the amplitude of light; Improve the level of pull rod technology, reduce the boron oxygen content, reduce the defect density, improve the uniformity of resistivity. Method Two: Replacement of Boron with Produce: This method did not find photo-induced attenuation. Method 3: The use of magnetron direct-draw monocrystalline silicon, zone melting single crystal silicon technology, can change the quality of the silicon. The latter avoids the defect that a large amount of oxygen enters the crystalline silicon, thereby thoroughly solving the problem of the attenuation of the boron-doped silicon wafer and the photovoltaic module. Method 4: The use of p-doped n-type silicon instead of boron-doped p-type silicon wafer, n-type silicon wafer can solve the problem of light attenuation, but from the perspective of the existing technology and process, there is no advantage in conversion efficiency and manufacturing costs. Method 5: Improve the processing level of the silicon wafer to improve the consistency of the silicon wafer performance, and further improve the wafer quality by means of a silicon sorter, such as a solar photovoltaic cell module attenuation tester. Method 6: Since the photo-induced attenuation of the photovoltaic module is caused by the initial photo-induced attenuation of the battery, the silicon wafer can be photo-induced before the manufacture of the photovoltaic module, and the photo-induced attenuation can be controlled within the measurement error, which greatly improves the The stability of the output power of the component. A summary of the initial photo-induced attenuation test of photovoltaic modules: 1 The attenuation of the performance of solar cells will inevitably lead to a decrease in the output power of photovoltaic modules, which can easily cause hot-spot effects in the components, and cause a series of potential safety hazards in photovoltaic power plants. 2 If the current between the battery string and the string is inconsistent within the assembly, the step curve can be seen on the IV curve of the bypass diode assembly. 3 The photo-induced attenuation of the components can be examined by measuring the output characteristics of the components before and after illumination and infrared imaging analysis. Second, aging decay, and slow decay in the long-term application of photovoltaic modules in photovoltaic power plants. This attenuation is related to the slow decay of the cells in photovoltaic modules. Generally speaking, it appears that the decay speed of photovoltaic modules and the production process and module packaging materials of photovoltaic modules. The component application environment is positively correlated. Common cracking, yellowing of the appearance, wind and sand wear, hot spots, and aging of the components all can accelerate the power attenuation of the components. The problem of aging degradation of PV modules is mainly related to the process and materials of PV modules and common quality problems. Third, the potential induced attenuation effect of PID photovoltaic components: modern researchers generally believe that the attenuation of this component exists in the high voltage between the component's internal circuit and its grounded metal frame will cause the power attenuation of the component, in addition to potential induced attenuation. It is also related to battery, glass, EVA, temperature, humidity and voltage. Attenuation mechanism: Under the action of high voltage, the upper surface of the assembly battery encapsulating material and the assembly, the ion migration of the material on the lower surface occurs, the phenomenon of hot carriers occurs in the battery, and the charge distribution reduces the battery activity. The potential-induced attenuation effect solution method can reduce the output power loss of the component and improve the stability of the photovoltaic power generation. It can ensure that the life of the photovoltaic power plant becomes a direction for the future research of photovoltaic power plant efficiency. 200mm (8 Inch) Flat Cut-off Disc B&H TOOLS CO., LTD. , https://www.bandhtools.com
Analysis of Photovoltaic Module Attenuation in Photovoltaic Power Plant