Product Information / Self polishing treatment of ultra white rolled photovoltaic glass surface

Self polishing treatment of ultra white rolled photovoltaic glass surface

10-29-2024

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1. Introduction

 

Solar panel cover glass, also known as solar glass cover, has the characteristics of high solar photovoltaic conversion rate, low panel damage rate, high strength, and good flatness. It can fully transmit sunlight for absorption by solar cells. At present, the commonly used solar cell module cover glass consists of a surface with a certain roughness and a surface with embossed layers. When packaging solar cell modules, the surface with a certain degree of coarseness is oriented towards the side where sunlight enters, and the surface with embossed layers is oriented towards the side of the solar cell, and is sealed and bonded to the solar cell through an EVA layer.

 

All along, when incident light passes through a surface with a certain roughness, there is still a loss of about 7% of reflected light. When the roughness of the glass surface is further reduced, the loss of reflected light reaches about 10%. So, how to effectively reduce the reflected light incident on the cover glass of solar cell modules has become a research focus for further improving the transmittance of solar cell module cover glass. To ensure the roughness requirements of the glass surface, it is currently common to increase the roughness of the roller surface on the rolling mill. However, in the continuous production process, the roughness decreases continuously with the extension of production time, and after more than 30 days of production, the surface of the glass plate shows obvious reflection. The main reason is that the ultra white rolled glass after rolling still has a high temperature, and the self polishing of the glass is severe, resulting in a decrease in roughness and an increasing loss of reflected light. Therefore, it is urgent to provide a self polishing device and method for the surface of ultra white rolled photovoltaic glass that can reduce the reflection loss when sunlight is incident, without causing significant fluctuations in the appearance quality of the glass plate, and has a simple manufacturing process and low cost.

 

2. Experimental materials and methods

 

Install a wind bag of equal length to the rolling roller above the glass plate after the rolling roller: adjust the cooling position of the wind between the rolling roller and the transition roller table. At this time, the surface temperature of the glass plate is above 700 ℃, and it still has strong self polishing properties; Adjust the air volume of the compressed air and perform rapid cooling and shaping treatment on the surface of the glass plate just out of the rolling roller. Using physics methods to solve the self polishing problem caused by the long material properties of glass bodies. A simple and cost-effective solution to the problem of self polishing on the surface of ultra white rolled photovoltaics.

 

3. Results and Discussion

 

(1) The influence of the distance between the wind turbine and the upper roller of the rolling mill and the glass plate

 

The wind turbine and glass perform direct convective heat transfer, and the closer the distance, the better the effect. But when the distance is close, the wind pressure should not be too high to avoid longitudinal color difference. It is also not advisable to go too far, as excessive airflow directly affects the temperature of the overflow outlet, causing a large amount of falling objects.

 

(2) Production thickness impact

 

Experiments have shown that the effect is actually worse when the thickness of the thick plate is 6mm or more. The main reason is that the rolling method is used for forming thick plates. When producing thick plates, the pre roll temperature control is about 30 ℃ lower than 3mm, and the rolling auxiliary speed is also 40% lower. In this way, the temperature on the surface of the glass plate is lower after being rolled by the rolling roller, so as to leave the self polishing temperature zone of the glass.

 

(3) The influence of roller temperature on the pressure roller

 

When the upper roller overheats, there is a significant decrease in the surface temperature of the upper roller when using this device, and the roughness of the product remains stable after installing the wind pack. When the lower roller is heating up, this device cannot be used. During the test, the surface of the plate undergoes continuous deformation and there is no qualified plate.

 

(4) Compressed air size and quality requirements

 

According to the situation of the board surface, it can be seen from the first three points that there are significant differences in production processes, and it is recommended to adjust the air volume opening from small to large. When the opening of compressed air reaches 50% or more during the experiment, longitudinal color difference is prone to occur. Southern enterprises do not recommend using compressed air sources with atomized gas. The atomized gas has a high water content, and if not drained in time, water may be blown onto the glass plate with the compressed air, causing continuous degradation and other effects. It is best to use dry execution gas.

 

4. Conclusion

 

It can effectively solve the self polishing treatment device and method for the surface of ultra white rolled photovoltaic glass, maintain the stability of the product, solve the self polishing of the surface of ultra white stretched photovoltaic glass, effectively prevent the serious reflection of light on the upper surface of ultra white rolled photovoltaic glass, and prevent the decrease in photoelectric conversion rate caused by increased incident light loss. But when the thickness of the glass plate reaches 6mm, there is almost no effect, and the effect is more ideal when producing 3mm; If the lower roller overheats, this method is not applicable.

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