Environmental Test for PV Solar Panels

Introduction

Photovoltaic module 85℃ 85%RH test chamber is an instrument and equipment for testing the performance of solar cells, which is a widely used tool in laboratory and on-site quality inspection and evaluation, used to evaluate the power output performance of solar panels, and detect the function and performance of solar panels from all aspects.

First of all, the working principle of the photovoltaic module double 85 test chamber is to adopt the principle of thermal double 85, on the basis of this principle, the use of multiple heating resistance AC sample boxes, through the constant heating device to carry out solar cell thermal drift test. The surface temperature of the test sample is 85 °C, and then the test sample is exposed to the natural environment, and the test sample is affected by various environmental influences such as roof, sunshine conditions, air flow rate, temperature and humidity, and continuously tested for a period of time with the original characteristics, such as 20 minutes, and then measured the last surface temperature. By comparing with the initial temperature and various factors of temperature, combined with simulation calculations and other technologies, the power output of solar panels can be calculated.

Secondly, these detection methods can cover the main performance parameters of photovoltaic modules, and can also be used for on-site environmental simulation, which has reliability for the test results of different environments, so that the conversion efficiency and power of photovoltaic modules can be effectively evaluated, as well as the thermal drift performance of the components, improve the reliability and durability of the components, and also detect the reliability of the components for a long time.

In addition, the solar cell double 85 test chamber has a variety of special functions, such as constant temperature test and automatic temperature regulation, which can be continuously measured for a long time without repeated adjustment; The test system is automatically adjusted according to the user's usage habits and combined with the on-site environment; The test results are clear and clear, easy to monitor and record the results in real time, and the measurement results can be transmitted in real time, so as to control the system; The number of test samples is large, and the test is easy to repeat.In short, photovoltaic module double 85 test chamber is a widely used tool in the process of solar cell performance evaluation and testing, which can realize the analysis of solar panel performance, thereby improving energy utilization, meeting the actual needs of customers, and promoting the development of various technologies for solar cell applications. In the future, the PV module double 85 test chamber will play a greater role in high-power solar cells, thermal drift detection, thermal cycle detection, sun shield testing, series module testing and so on.Relevant Standards for PV Solar Panel Reliability test.

Relevant Standards for PV Solar Panel Reliability Test

Previous standards only regarded the backplane as an integral part of the component, and were tested and certified together with the component. With the increasing awareness of the importance of backplane and component reliability and durability, component-based and individual backplane testing standards and specifications are gradually being established and improved. Internationally, the working group under IEC TC82 of the International Electrotechnical Commission is revising the second edition of IEC 61730 (Safety Certification of Photovoltaic Modules), and drafting new backplane material testing standards, such as IEC 62788-2 (Photovoltaic Module Material Testing Procedures) : Front and Back Sheet Plastics) and IEC 62788-7-2 (Test Procedures for Photovoltaic Materials - Part 7-2: Environmental Exposure - Accelerated Weathering Tests for Plastics), these international standards propose more and more higher requirement. In addition, the International Photovoltaic Quality Assurance Task Force (PVQAT) was established in 2011. One of its main tasks is to distinguish the relative durability of module design by promoting the formulation and revision of international standards and establishing a photovoltaic quality assurance evaluation system. Among them, working group 5 mainly studies the comprehensive influence of temperature, humidity and ultraviolet rays on components and materials. In addition, the National Renewable Energy Laboratory (NREL) also took the lead in formulating the "Quality Plus" standard, based on IEC61215, through longer test cycles, test sequences, new characterization methods and components with bias requirements such as testing, distinguishing different components and ensuring long-term component reliability.

Damp Heat Aging, DH

Both IEC 61215 and 61730 clearly require a 1000-hour damp heat aging test on the components to determine whether the components have obvious power attenuation and failure (such as leakage or delamination, etc.). Some backplane manufacturers conduct 2000 hours or even 3000 hours on the backplane Hours of damp heat test, which will cause obvious hydrolysis and embrittlement of the PET polyester material in the backplane. But does the backplane fail outdoors due to hydrolytic embrittlement? After analysis, it is found that 1000 hours of damp heat aging can simulate the degree of hydrolysis of PET polyester materials in any part of the world for more than 25 years. The test results also confirmed that 1,000 hours of double 85 testing is sufficient to simulate a 25-year model in any climate. In the latest version of IEC61730, a 1000-hour damp heat aging test is also required for components.

UV Aging

IEC 61215 requires 15kWh/m2 UV pretreatment on the front of the module. The purpose of the test is to pretreat the module with ultraviolet (UV) radiation before the thermal cycle/wet freezing test to determine the UV attenuation of related materials and adhesion.

The industry has agreed that this dose is much lower than the actual UV exposure dose received by modules that have been outdoors for 25 years, and the air surface of the module backplane has not been exposed to UV radiation. Therefore, the draft international standard for backplane IEC 62788-2 and the national standard for backplane GB/T 31034-2014 both increase the dose of UV testing. According to the average annual UV radiation dose and 12% average UV reflectance in typical climate areas, the 25-year cumulative UV dose on the back of the module (junction box surface) in desert areas reaches 275kWh/m2, even in mild areas it reaches 171kWh /m2, equivalent to 11 to 18 times the UV pretreatment dose of IEC 61215.

In addition, it should be pointed out that the UV aging does not reach the corresponding UV dose to simulate the outdoor aging of the backplane material for 25 years. It is also necessary to design a reasonable sample structure and use an appropriate light source (for example, a high proportion of short-wavelength UVB may cause non-outdoor aging). Under the appropriate ultraviolet intensity and temperature, the influence of humidity and other environmental stresses is introduced, and the corresponding correlation is made with the long-term outdoor aging mechanism and degree.

Weathering Resistance

Weathering resistance test is a test method that combines ultraviolet radiation with temperature and humidity, and aging materials and components at the same time. The test standard can refer to ASTM G155-2005 (operation rules for xenon arc lamp equipment for exposure of non-metallic materials) ), has been widely used in the field of industrial products such as automobiles. Compared with the single test in the existing IEC61215, the weather resistance test combines the three important environmental factors of light, heat and humidity to investigate the aging of components and materials under the synergistic effect of multiple factors, which can better simulate the actual outdoor situation . Amendments to the second edition of IEC 61730 and IEC 62788-7-2(Photovoltaic Materials Testing Procedures - Part 7-2: Environmental Exposure - Accelerated Weathering Test of Plastics) During the drafting of the two standards, the weathering test was widely discussed and was once included in the text, but due to equipment and part Existing products are difficult to meet the test requirements and some manufacturers objected. Weather resistance testing has long been widely recognized in the photovoltaic field.

The weather resistance test not only needs to control the intensity of light and temperature and humidity, in order to better simulate the outdoor environment, it also needs to spray the samples intermittently to simulate natural rain and night surface condensation, and use the adsorption and desorption of water by materials , to promote the aging of the material, and at the same time produce a temperature impact on the surface of the sample being irradiated. According to the general international standard ISO4892-2 plastics weathering resistance of plastics - method of exposure to laboratory light source (Part 2: Xenon arc lamp), the fracture of weathering resistance aging test of different backplane with and without spraying Changes in elongation were compared. It can be seen from the figure that the elongation at break of the hydrolysis-resistant and UV-resistant HPET1 polyester backplane does not decrease significantly after the xenon lamp aging test for 3000 hours, but after the introduction of appropriate water spray during the xenon lamp aging process, the polyester backplane and 1500 hours of aging, the elongation at break of the board decreased significantly.

Salt Spray Corrosion

The salt spray corrosion resistance test of photovoltaic modules mainly refers to the IEC61701-2011 (salt spray corrosion test of photovoltaic modules) standard, using 5% salt water spray and 50% humidity static cycle to evaluate the salt spray corrosion of materials. But even with the most stringent test level 7, the salt water spraying time in the test is only tens of hours, and the rest of the time is the resting time. It is difficult to simulate the real situation of the module used in the coastal environment for 25 years. The aluminum profile and aluminum-plastic panel industry generally adopts the AAMA 2605-5 standard (spontaneous design specifications, performance requirements and inspection procedures for organic coatings with excellent performance on the surface of extruded aluminum profiles and panels), and the long-term coating up to 4000 hours of salt spray corrosion test to evaluate the long-term salt spray corrosion resistance of the coating. Therefore, it is necessary to strengthen the salt spray corrosion test of components and backplane materials installed in coastal and saline-alkali areas.

Summary

The photovoltaic industry is developing rapidly and has a complete photovoltaic industry and market. The rapid development and frequent product quality problems have also attracted the attention of relevant manufacturers, certification agencies, investors and the government. In order to speed up the transformation and upgrading of the photovoltaic industry, it is necessary to establish scientific and complete supporting standards as soon as possible to regulate the photovoltaic industry and ensure the healthy, orderly and rapid development of the market.

LIB Test Chambers For Solar Panel Testing

LIB Test Chamber For Solar Panel Testing is for PV modules( solar panels) thermal cycling, humidity freeze cycle, and damp heat RH testing, to test whether PV modules can withstand high temperature with humidity and low temperature, to test its fatigue and thermal failure after temperature repeated changes, to confirm its thermal stress PV modules generated under high humidity circumstance and capacity of long-term resistance to moisture penetration. This test chamber is widely used in solar panels testing.

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