Abstract: Water vapor transmission rate is an important performance index to characterize the barrier property of solar backsheet (film) to external water vapor (moisture). It can effectively monitor the protection performance of solar battery backplane against internal battery components and avoid solar cells. It is oxidized in the external environment. This article uses the W3/330 water vapor transmission rate test system independently researched and manufactured by Jinan Languang Electromechanical Technology Co., Ltd. to test the water vapor transmission rate of the solar backsheet (film), and briefly describes the parameters, the scope of application, and the test of the equipment. The process provides a reference for how the solar energy equipment production industry can verify the barrier properties of solar back sheet materials to external moisture. Keywords: water vapor transmission rate, moisture barrier, water vapor barrier, solar backsheet (film), solar cell, battery oxidation, water vapor transmission rate test system 1 , the meaning The core component of solar energy equipment is the solar panel, which can convert solar energy into electrical energy, enabling the development of renewable energy and clean energy. At present, the useful life of solar products is mostly required to be more than 25 years, so its key component solar battery backplane (herein referred to as the solar backplane) must have extremely high protection effect on the cells of the internal photovoltaic modules. Solar cell modules are generally laminated by " photovoltaic glass -EVA film - solar panel -EVA film - backsheet " in the aluminum alloy frame. The commonly used solar backsheet materials mainly include TPT backsheet and BBF backsheet. TPE backsheet, EVA backsheet, etc., in which the TPT backsheet has a high barrier property, which is a three-layer composite film of PVF (or PVDF ) /PET/PVF ( PVDF ). Since the solar cell module is placed outdoors for a long time, the back plate must have excellent insulation, water resistance, aging resistance, etc., and should have high peel strength, tensile strength, and good thermal shrinkage and other properties. One of the most important indicators is the water vapor transmission rate, which is the barrier to the external moisture. If the water vapor transmission rate of the back sheet (film) is relatively large, that is, the barrier property against water vapor (moisture) in the outside air is poor, the moisture will infiltrate into the back sheet to the inside of the solar back sheet, so that the EVA owns Adhesion performance deteriorates, causing the backplane to detach from the EVA , causing more moisture to come into contact with the cell and oxidize the cell. In this paper, the W3/330 water vapor transmission rate test system independently developed by Jinan Languang Electromechanical Technology Co., Ltd. was used to test the water vapor transmission rate of the solar backsheet (film) in order to verify the resistance of the solar back sheet material to external moisture. How is sex? Figure 1 Solar Back Sheet Material 2 , the status quo At present, domestic methods for measuring the water vapor transmission rate of soft plastic materials include the weighing method ( cup method ) , electrolysis method, humidity method, and infrared method. Reference standards are GB 1037-1988 "Plastic Films and Sheets. Test method for water vapor permeability of cups", GB/T 16928-1997 "Testing methods for moisture permeability of packaging materials ", GB/T 21529-2008 "Determination of water vapor transmission rate of plastic films and sheets - Electrolytic sensor method" , GB / T 30412-2013 "water vapor transmission rate of plastic film and sheet of the humidity sensor measurement method" (published 2014 December 1 embodiment). This article uses the electrolytic method to test the water vapor transmission rate of pork floss packaging, based on the standard GB/T 21529-2008 "Determination of plastic film and sheet water vapor transmission rate - electrolytic sensor method." 3 , test sample A brand of solar battery backsheet (film). 4 , test equipment The test equipment used in this article is Labthink blue light W3/330 water vapor transmission rate test system. Figure 3 W3/330 Water Vapor Transmission Rate Test System 4.1 Test principle The W3/330 adopts the principle of electrolytic sensor test. Nitrogen with stable relative humidity flows on one side of the membrane, and dry nitrogen flows on the other side of the membrane. Due to the presence of a moisture gradient, water vapor diffuses through the membrane from the high humidity side. On the low-humidity side, on the low-humidity side, the transmitted water vapor is carried by the flowing dry nitrogen gas to the sensor, and when it enters the sensor, an electrical signal of the same proportion is generated. By analyzing and calculating the electrical signal of the sensor, the water vapor of the sample is obtained. Transmissibility and other parameters. For packaging containers, dry nitrogen flows inside the container and the outside of the container is in a highly humid state. 4.2 Equipment Parameters 4.3 Scope of application (1) This equipment is applicable to the testing of the water vapor transmission rate of packages such as films, sheets, paper, paperboard, composite materials and containers. The films include various plastic films, plastic composite films, paper-plastic composite films, coextruded films, aluminized films, aluminum foils, aluminum foil composite films, glass fiber aluminum foil composite films, etc.; sheet materials including various engineering plastics, rubbers , sheet materials such as building materials, such as PP sheet, PVC sheet, PVDC sheet, etc.; paper, cardboard and composite materials including paper, cardboard, etc., such as cigarette pack aluminum paper, paper aluminum plastic composite sheet, etc.; The device can also be used for testing the water vapor transmission rate of special packages such as solar back panels, liquid crystal display films, pharmaceutical blisters, pharmaceutical plastic bottles, sterile protective film, automotive fuel tanks, and battery plastic housings. Containers include water vapor transmission rate tests for bottles, bags, cans, boxes, and barrels made of plastics, rubber, paper, paper-plastic composites, glass, and metal, such as Coke bottles, peanut oil drums, Tetra Pak packaging, and vacuum. Packaging bags, metal packaging bags, metal three-piece cans, plastic cosmetic hose packaging, toothpaste hose packaging, jelly cups, etc. (2) This equipment complies with many national and international standards such as GB/T 21529 , ISO 15106-3 , DIN 53122-2 , YBB 00092003, etc. 5 , the test process (1) cut with a dedicated sampler samples were taken of 108 mm × 108 mm from the sample surface 3. (2) The three samples were clamped in a test chamber of the instrument 3, tightening test chamber. (3) Set the sample thickness, test temperature, test humidity and other parameters. (4) Adjust the pressure of nitrogen gas so that the humidity in the test chamber reaches the set value, and pass the nitrogen flow adjustment knob so that the nitrogen flow in the upper and lower chambers reaches the standard value. (5) Click to start the test option and the test begins. The instrument automatically records the changes in the water molecule content on the low-humidity side of the test and calculates the final test results. Figure 4 sample mounting process 6 , test results Water vapor transmission rate values of the three samples tested were: 1.2405 g / (m2 · 24h ), 1.3114 g / (m2 · 24h), 1.3075 g / (m2 · 24h). 7. Conclusion W3/330 Water Vapor Transmission Rate Test System is a professional equipment for the barrier properties of water vapor in films, sheets, and containers. It has the advantages of high detection accuracy, good reproducibility of test results, etc. The test of water vapor transmission rate can effectively monitor the service life of solar cells. In addition to the water vapor transmission rate test equipment, Labthink can also provide you with testing equipment for physical and mechanical strength testing such as tensile testing machines that can test the tensile properties and peel strength of solar back sheets (films). You can visit the website of Jinan Languang Company to view or call for consultation. The more you understand, the more trust! Jinan Languang Electromechanical Technology Co., Ltd. is willing to take this opportunity to increase technical exchanges and cooperation with enterprises and institutions in the industry. Stitching Gluing System LLY PACK(foshan) Co.,Ltd. , https://www.llypack.com
