&Nbsp& nbsp; Solar energy, as a widely distributed green, pollution-free and clean energy source, is the first choice for the sustainable development of national energy. Photovoltaic power generation is of great significance for energy conservation and emission reduction, winning the battle to protect the blue sky, and building a beautiful China< br />
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After 2010, against the backdrop of a slowdown in demand for the solar photovoltaic industry in Europe, China's solar photovoltaic industry rapidly rose and became the main driving force for the development of the global solar photovoltaic industry. According to relevant statistical data, as of the end of 2017, China's newly added grid connected photovoltaic installed capacity reached 53GW, a year-on-year increase of over 50%, and the cumulative grid connected installed capacity reached 131GW, ranking first in the world. In 2018, the newly installed capacity of photovoltaic power generation in China exceeded 43GW, a year-on-year decrease of 18%, and the cumulative installed capacity exceeded 170GW. Although photovoltaic 5 in 2018The introduction of the. 31 new policy has led to a decrease in the number of newly installed photovoltaic capacity in China. However, as the photovoltaic power generation industry has entered the era of parity grid connection, there is still huge development space for the domestic photovoltaic industry in the future. The just concluded National People's Congress and Chinese People's Political Consultative Conference have released multiple favorable policies to promote the healthy development of the photovoltaic industry. It is expected that the newly added grid connected installed capacity of photovoltaics in China will reach 43GW in 2019, with a cumulative installed capacity of 216GW. In the future, the global photovoltaic market will continue to maintain a good growth trend under the leadership of countries such as China, Japan, and the United States< br />
 




 
Basic composition and adhesive requirements of solar photovoltaic modules< br />
A set of solar photovoltaic modules consists of seven main parts: tempered glass, EVA film, solar cells, backsheet, aluminum alloy frame, junction box, and module adhesive< br />
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Solar photovoltaic modules are mainly used outdoors, so the selected sealant must adapt to the climate differences of different regions when used outdoors for a long time, such as high temperature and humidity, high and low temperature, strong ultraviolet radiation, ozone, wind and rain, and other natural conditions< br />
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Organic silicone sealant is widely used in the packaging production of solar photovoltaic modules due to its excellent high and low temperature resistance, excellent adhesion, outstanding aging resistance, excellent insulation performance, good elasticity, hydrophobicity, simple application process, and high production efficiency< br />
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Requirements for adhesive used for bonding and sealing of frames, backboards, and junction boxes

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Solar cells are the core components of solar photovoltaic power generation systems. Due to defects such as thinness, brittleness, and susceptibility to oxidation in solar cells, protective packaging is required to form stable solar cell modules. Therefore, the performance requirements for the adhesive used for bonding and sealing are as follows:< br />
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(1) Fast curing speed and simple production operation process< br />
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(2) Has good adhesion to various backboards, frames, and junction boxes< br />
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(3) Low thermal stress, good heat dissipation, good weather resistance, good UV resistance, good waterproof performance, and good electrical insulation< br />
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(4) Maintain the physical and electrical properties of sealed components under a wide range of temperature (-40 ℃~150 ℃), humidity, and harsh environmental conditions< br />
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(5) Absorb the stress generated by impact and vibration, waterproof sealing keeps the battery cells dry and not damaged by stress, anti yellowing, repairable, and has a lifespan of over 20 years< br />
 


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Requirements for adhesive used for sealing junction boxes

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The solar photovoltaic junction box is a connector between the solar cell array composed of solar cell modules and the solar charging control device. It is an essential supporting component of solar power generation equipment, and the performance requirements for its sealing adhesive are as follows:< br />
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(1) Easy to operate, with good self leveling and self foaming properties, and fast curing< br />
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(2) After curing, it has good waterproof, insulation, and thermal conductivity properties, and good adhesion< br />
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(3) Excellent anti-aging performance. Outdoor use can resist the adverse effects of ultraviolet light, ozone, moisture, acid and alkali, and maintain physical properties and electrical insulation performance< br />
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The national recommended standard GB/T 29595-2013 "Silicone rubber sealant for ground photovoltaic module sealing materials" translates the above requirements into corresponding technical specifications. In combination with applications, the main factors that need to be examined for the adhesive used for bonding and sealing frames, backboards, and junction boxes are their curing speed, as well as their adhesion, mechanical properties, and electrical properties after wet heat aging; The main factors to be examined for the sealing adhesive used in junction boxes are its shelf life, as well as its adhesion, heat dissipation, and electrical performance before and after wet heat aging.


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Common problems and solutions for adhesives used in solar photovoltaic modules

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1. Adhesive for bonding and sealing frames, backboards, and junction boxes

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① Explosive glue:< br />
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Reason: For large barrel packaging, it is generally caused by unstable dispensing pressure< br />
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Solution: Using a stable gas source and a well matched pressure plate can effectively solve this problem< br />
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② Bubble:< br />
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Reason: Usually due to insufficient glue application, the gas is sealed in the frame< br />
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Solution: Apply more glue than the filling amount required for the gap between the laminated board and the frame to solve the bubble problem< br />
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③ Slow curing:< br />
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Reason: Organic silicone sealant is generally cured by absorbing moisture from the air, and the curing speed is mainly related to the temperature and humidity of the adhesive environment, in addition to the formula< br />
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Solution: It can be improved by adjusting the ambient temperature and humidity< br />
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2. Sealing glue for junction box

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① Inconsistent solidification:< br />
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Reason: Generally caused by uneven mixing of A and B adhesives< br />
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Solution: Mix A and B glue evenly before use, adjust the dispensing pressure of A and B components appropriately, and fine tune the ratio of A and B components to solve the problem< br />
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② After solidification, there are many pores inside the colloid:< br />
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Reason: Poor self foaming properties of colloids< br />
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Solution: Reduce the viscosity of component A appropriately, increase colloid fluidity, and improve ?Enhance the heat dissipation performance of the junction box.