Application of Silicone Sealant in Solar Modules

Introduction

Solar module manufacturing appears to be quite simple, yet the performance and life cycle of the module depends on every individual part, whose effective coordination is expected to extend the durable life of solar module to 25 years or longer. Today, we look at solar sealant, perhaps the least noticed, but a critical and vital material to ensure solar modules’ smooth and long-term operation.

Background

The success of solar PV as the primary renewable energy option is a settled fact today. According to Bloomberg New Energy Finance (BNEF), the global installed capacity of new PV in 2021 was 183GW, with a year-on-year increase of more than 30%. It was predicted that the global installed capacity of new PV will be 228GW (DC) in 2022 and 334GW (DC) in 2030. Solar PV has a long runway of growth under the leadership of China, India, the United States, and other countries.

Ignorance of Any Part of Solar Module Causes Irreversible Damages on the Entirety

A complete set of solar photovoltaic modules is roughly composed of seven parts: tempered glass, EVA film, solar cell, back sheet, aluminum alloy frame, junction box, and sealant. Among these, solar cells are the core components of the solar photovoltaic power generation system. As solar cells are thin, brittle, and easy to oxidize, sealants, act as indispensable and critical roles in protecting those precision parts. Sealants are key to ensuring a stable working performance over extended periods, as solar panels are designed to serve. Considering that solar photovoltaic modules are mainly used outdoors, they have to adapt to the climatic changes in different regional environments such as high temperature, high humidity, high and low temperature, strong ultraviolet, ozone, wind, and rain.

Well Tested Means Excellent Performance

At Guibao, our GUIBAO 888A Silicone Sealant for Solar Modules goes through some of the most rigorous tests before being passed for delivery.

Sample Preparation and Testing

All samples shall be placed under the standard conditions of (23 ± 2) ℃ and relative humidity of (50 ± 5) % for 24 hours.

Curing Depth

Grounded on the method specified in 5.8 of GB/T 29595-2013, firstly, the Teflon experimental mold in Fig. 2 is cleaned and dried with alcohol. Secondly, we squeeze the sealant into the mold, Finally, we measure the thickness of the deepest curing layer with a vernier caliper.

Adhesion Test

According to the method specified in appendix B of GB/T 29595-2013, the base material shall be anodic aluminum oxide sheet or test back sheet and the back sheet shall be determined by the supplier and the buyer through negotiation.

Tensile strength and elongation at break

The sample preparation test shall be carried out based on the requirements of GB/T 528-2009.

Experimental results and discussion

GB/T 29595-2013, or the Silicone rubber sealant for ground photovoltaic module sealing materials, puts forward corresponding technical index requirements for silicone sealant. The adhesion used for bonding and sealing of frame, back sheet and junction box, the curing speed, fixed elongation adhesion and adhesion after damp and heat aging of silicone sealant can be investigated on site.

Guibao Aces The Curing Test

The deep curing speed of GUIBAO 888A silicone sealant for solar modules is 3mm at 24 hours as detailed in Fig. 3, which is much higher than the standard requirement of 2mm. As result, this product can improve the production efficiency and turnover speed of solar photovoltaic modules.

Adhesion Test

The good adhesion of silicone sealant to the frame and back sheet is conductive to improve the service life of solar modules.

However, the materials of solar back sheet include TPT, TPE, BBF, APE, and EVA. At the same time, the back sheet involves the lamination treatment in practical application and the lamination process leads to changes in the surface of the back sheet. After testing, GUIBAO 888A has good adhesion to various types of back sheets in different treatment methods.

Tensile strength and elongation at break

In the laboratory, the anti-aging performance of silicone sealant in outdoor is evaluated by high temperature and high humidity, cold heat cycle, wet cold cycle, and UV aging test.

It can be seen from table 1 that the tensile strength and elongation at break of GUIBAO 888A keep good performance under different aging test conditions, indicating that GUIBAO 888A can be normally used outdoors for 25 years.

Analysis of common problems in the application of silicone sealant in photovoltaic modules

As far as the problems of silicone sealant applied in photovoltaic modules are concerned, the most common ones, bubbling and poor bonding are directly related to the service life of products, and excessive curing time will weaken the production flow efficiency.

Bubble problem

The following two situations are the main reasons to explain why the bubble problem exists: (1) there is incomplete discharge of air in the process of applying sealant; (2) the sealing ring of pressure sheet gets damaged.

Slow curing

Silicone sealant is generally cured by absorbing moisture in the air. The curing speed is mainly related to the temperature and humidity of the environment. The curing time of silicone sealant can be shortened by increasing the temperature and humidity.

Poor adhesion between sealant and back sheet

In order to ensure good adhesion, the adhesion test needs to be carried out in advance, and the adhesion test with batch stripping should be executed regularly for supervision.

Conclusion

GUIBAO 888A has fast curing speed, excellent adhesion properties, and good weatherability, which has been widely used in many solar energy enterprises. That is the one reason why Guibao is always the preferred solar sealant supplier to some of the biggest names in the module manufacturing business. It is also the reason we remain committed to investing in research to ensure our sealants are always the most dependable and advanced materials behind your solar module.

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