Solar photovoltaic modules are mainly used outdoors, so the sealant selected must be able to adapt to the climatic differences in 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.
Silicone sealants are widely used in the encapsulation and production of solar photovoltaic modules due to their excellent high and low temperature resistance, superior adhesion, outstanding aging resistance, excellent insulation properties, good elasticity, hydrophobicity, simple application process, and high production efficiency.
1. Requirements for adhesives used for bonding and sealing the frame, back panel, and junction box
Solar cells are the core component of solar photovoltaic power generation systems. Due to their thinness, brittleness, and susceptibility to oxidation, solar cells require protective encapsulation to form stable solar cell modules. Therefore, the performance requirements for the adhesives used for bonding and sealing are as follows:
(1) Fast curing speed and simple production process;
(2) It has good adhesion to various backplates, frames, and junction boxes;
(3) It has low thermal stress, good heat dissipation, good weather resistance, good UV resistance, good waterproof performance, and good electrical insulation.
(4) Maintain the physical and electrical properties of the sealing components under a wide range of temperature (-40℃~150℃), humidity, and harsh environmental conditions;
(5) It absorbs the stress generated by impact and vibration, and the waterproof seal keeps the battery cells dry and prevents them from being damaged by stress. It is resistant to yellowing, repairable, and has a lifespan of more than 20 years.
2. Requirements for potting adhesive used in junction boxes
A solar photovoltaic junction box is a connector that connects the solar cell array (composed of solar cell modules) to the solar charging control device. It is an essential component of solar power generation equipment, and the performance requirements for its potting compound are as follows:
(1) It is easy to operate, has good self-leveling and self-foaming properties, and cures quickly;
(2) After curing, it has good waterproof, insulating, and thermal conductivity properties, and good adhesion;
(3) Excellent anti-aging properties. When used outdoors, it can resist the adverse effects of ultraviolet light, ozone, moisture, acid and alkali, and maintain physical properties and electrical insulation properties.
In terms of application, the main factors to consider for adhesives used for bonding and sealing frames, back panels, and junction boxes are their curing speed, adhesion, mechanical properties, and electrical properties after hygrothermal aging; while the main factors to consider for adhesives used for potting junction boxes are their pot life and adhesion, heat dissipation, and electrical properties before and after hygrothermal aging.
