KR102159244B1 - Cleaner composition for glass substrate for waste solar cell and method for cleaning the glass substrate for solar cell using thereof - Google Patents

Abstract

A cleaning liquid composition for cleaning a glass substrate of a waste solar cell is provided. In one embodiment, a composition for cleaning a glass substrate separated from a waste solar cell by an oxidation process, comprising ammonium difluoride ((NH ₄ )HF ₂ ) 5 to 20 parts by weight per 100 parts by weight of the composition I can.

Description

Cleaning liquid composition for cleaning glass substrates of waste solar cells, and cleaning method for glass substrates of waste solar cells using the same

The present invention relates to a cleaning liquid composition for cleaning a glass substrate of a waste solar cell, and a method for cleaning a glass substrate of a waste solar cell using the same, and more particularly, a cleaning liquid composition for cleaning a glass substrate of a waste solar cell that is harmless to the human body and excellent in removing contaminants, and It relates to a waste solar cell glass substrate cleaning method using this.

In general, a solar cell is a device that converts sunlight energy into electrical energy. Solar cells are tools that generate electricity using sunlight, an infinite energy source, and are already widely used in our lives.

A heat treatment process has been used to regenerate the conventional solar cell waste module. However, under general oxidation conditions, there is a problem in that the cell is damaged due to an exothermic reaction accompanying combustion of the encapsulant.

To solve this problem, a thermal nitric acid method, a microwave method, a method for treating chemicals, and the like have been developed in which heat treatment is performed for 1 to 2 hours in a nitrogen atmosphere and at a high temperature of 480°C for selective separation and recovery. However, the thermal nitric acid method has a problem in that a large amount of waste acid and additional harmful substances such as NOx are discharged, and the microwave method has a problem in that the cell is damaged due to an uneven temperature distribution, and the chemical method has a relatively high encapsulant removal rate. There is a problem that it is low.

However, as a method of recycling waste solar modules, the heat treatment process is considered to be the most efficient method to date. The surface of the glass substrate selectively separated by the heat treatment process as described above is contaminated by the combustion process. In general, a glass substrate for solar cells is in the form of a surface treatment (pyramid pattern or surface diffuse reflection treatment) to reduce the reflection of sunlight on the upper surface, that is, the incident surface of sunlight, and the lower surface, that is, the contact surface with the silicon wafer, is the surface of general glass. It has excellent smoothness like Accordingly, in order to recycle the glass substrate from the solar cell waste module, contamination is more severe on the uneven portion of the upper surface than the smooth lower surface in the separation combustion process, and thus it is necessary to effectively remove this.

Conventionally, in order to remove contaminants formed as a result of such a heat treatment process, a cleaning liquid containing hydrofluoric acid (hydrofluoric acid) was conventionally used. When such fluoric acid comes into contact with the body, it penetrates into the bones of the human body while hydrogen bonding with the body's water, and the bones can melt, and when drinking it, the organs in the human body are torn or melted. In addition, if you inhale a large amount of hydrofluoric acid gas (hydrofluoric acid) through your nose, there is a risk of nausea, vomiting, and blood loss.

Therefore, there is an urgent need to develop a cleaning liquid composition for cleaning glass substrates of waste solar cells that can replace such poisonous fluoric acid.

The problem to be solved by the present invention is to provide a cleaning liquid composition for cleaning a glass substrate of a waste solar cell having excellent cleaning power while replacing toxic hydrofluoric acid.

In addition, the problem to be solved by the present invention is to provide a method for cleaning a glass substrate of a waste solar cell.

The present invention is a composition for cleaning a glass substrate separated from a waste solar cell by an oxidation process in order to solve the above problems, ammonium difluoride ((NH ₄ )HF ₂ ) 5 per 100 parts by weight of the composition It provides a cleaning liquid composition for cleaning a glass substrate of a waste solar cell, comprising to 20 parts by weight.

At this time, the composition may include 10 to 20 parts by weight of acid, 5 to 20 parts by weight of hydrogen peroxide, and a diluent.

In addition, the composition may include 10 to 20 parts by weight of an acid, 30 to 60 parts by weight of a glass etching agent, and a diluent.

In this case, the glass etchant may have an acidity of 11 M.O/1N NaOH to 16 M.O/1N NaOH.

Meanwhile, the present invention provides a method for cleaning a glass substrate for a waste solar cell, comprising immersing the glass substrate in the cleaning liquid composition for cleaning a glass substrate for a waste solar cell described above in order to solve the above problems.

At this time, before immersing the glass substrate in the cleaning liquid composition for cleaning the waste solar cell glass substrate, it may further include polishing the glass substrate.

In this case, polishing the glass substrate may be performed using at least one of silicon carbide and aluminum oxide as an abrasive.

According to an embodiment of the present invention, even if harmful hydrofluoric acid is not used, the glass substrate separated from the waste solar cell can be cleaned by an oxidation process in a short time.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only this embodiment makes the disclosure of the present invention complete, and the contents of the present invention are provided to those of ordinary skill in the art. It is provided to inform you more completely.

In this specification, when an element is referred to as being positioned'above' or'below' another element, it means that the element is positioned directly above or'below' another element, or an additional element is placed between those elements. It includes all meanings that can be intervened. In this specification, the term'upper' or'lower' is a relative concept set at the observer's point of view, and if the observer's point of view is different,'upper' may mean'lower', and'lower' means'upper'. It could mean.

The present invention is for recycling of waste solar cells, and specifically, is a technology for recycling without causing cracks in the solar cell glass substrate.

A method of obtaining a glass substrate from a waste solar cell module may be performed by the following process. First, by applying heat to the solar cell module in an oxidizing atmosphere, the insulating protective layer surrounding the solar cell of the solar cell module may be removed, and the glass of the solar cell module may be obtained.

In this case, the removal of the insulating protective layer may be performed by applying heat of 400° C. to 650° C. to the solar cell module in an oxidizing atmosphere. Since the insulating protective layer may be made of a resin-based material, the insulating protective layer may be burned and removed when heat of 400°C or higher is applied.

At this time, the heat may be 650° C. or less, and this may be set in consideration of the melting point of the metal forming the electrode of the solar cell. For example, when the electrode is made of aluminum, the melting point of aluminum is 660°C. In this case, the temperature of the heat may be set lower than the melting point of aluminum, but may be set to 650° C. or less by leaving a margin.

In this way, in the process of removing the insulating protective layer of the waste solar cell, contaminants are formed on the glass substrate. The inventors of the present invention repeated related experiments in order to efficiently remove contaminants formed on the glass substrate using a cleaning solution that is harmless to the human body.

The cleaning liquid composition for cleaning a glass substrate of a waste solar cell according to an embodiment of the present invention includes ammonium difluoride ((NH ₄ )HF ₂ ), hydrogen peroxide, an acid and a diluent.

Ammonium difluoride is to replace the above-described hydrofluoric acid, and may be included in 5 to 20 parts by weight per 100 parts by weight of the composition. Ammonium difluoride is included together with hydrogen peroxide and an acid to be described later, and if the amount of ammonium difluoride is less than 5 parts by weight, the cleaning power of the glass substrate becomes remarkably poor, or the time for immersing the glass substrate in the composition is significantly longer. And, in the case of more than 20 parts by weight, the glass surface is excessively chemically eroded, i.e., too deeply etched to reduce the surface reflectance of the solar cell glass substrate. Problems that are difficult to achieve can arise.

In addition, 5 to 20 parts by weight of hydrogen peroxide, 10 to 20 parts by weight of acid, and 40 to 80 parts by weight of a diluent are included. The acid includes hydrochloric acid, perchloric acid, nitric acid, sulfuric acid, and the like, and, for example, sulfuric acid may be used. The diluent may be water, for example.

When hydrogen peroxide is used in an amount of less than 5 parts by weight, the time required for cleaning may be excessively increased, and homogeneous cleaning or etching itself may be difficult, and when used in excess of 20 parts by weight, the reaction product formed during cleaning is a glass substrate. There is a problem that uniform cleaning becomes difficult due to immersion or adhesion on the surface.

Meanwhile, the cleaning liquid composition for cleaning a glass substrate of a waste solar cell according to another embodiment of the present invention includes ammonium difluoride, a glass etching agent, an acid, and a diluent.

The glass etchant may be used with an acidity of 11 MO/1N NaOH to 16 MO/1N NaOH, for example, GT-250MG4 (13.0±0.5 MO/1N NaOH), Gfro-1 (14.6±0.5 MO/ 1N NaOH) or the like may be used. When the acidity of the glass etchant is less than 11 MO/1N NaOH, there is a problem that the cleaning power of the glass substrate is significantly deteriorated or the time to immerse the glass substrate in the composition is significantly longer, and is greater than 16 MO/1N NaOH. In this case, safety may be an issue in the cleaning process. For example, when GT-250MG4 is used with ammonium difluoride, the cleaning efficiency of the glass substrate of a waste solar cell is very good.

At this time, 5 to 20 parts by weight of ammonium difluoride, 30 to 60 parts by weight of a glass etchant, 10 to 20 parts by weight of an acid, and 25 to 40 parts by weight of a diluent may be included. For example, 5 to 20 parts by weight of ammonium difluoride, 50 to 60 parts by weight of a glass etching agent, 10 to 20 parts by weight of an acid, and 25 to 40 parts by weight of a diluent may be included.

The present invention also provides a method for cleaning a glass substrate of a waste solar cell using the cleaning liquid composition for cleaning a glass substrate of a waste solar cell.

For example, a glass substrate separated from a waste solar cell by an oxidation process is immersed in the above-described cleaning liquid composition for cleaning a glass substrate of a waste solar cell. As the immersion time increases, the cleaning power of the glass substrate increases, and for example, it may be immersed for 30 to 300 seconds, for example 30 to 150 seconds, and another example for 30 to 60 seconds.

The oxidation process may be performed at a high temperature, for example, may be performed by a heat treatment process of 400 ℃ to 650 ℃.

Thereafter, the immersed glass substrate may be treated with a neutralizing agent and washed with water.

Meanwhile, an embodiment of the present invention may further include polishing the glass substrate before immersing the glass substrate in the cleaning liquid composition.

Polishing the glass substrate may be performed using at least one of silicon carbide and aluminum oxide as an abrasive. For example, the silicon carbide may have a size of 500 to 950 microns, for example, 700 to 900 microns. In the case of using silicon carbide of the above size, it is possible to polish the glass substrate for a short time without damaging the glass substrate. In this case, as the polishing method, a sponge type, a brush type, or the like may be applied.

In addition, the number of meshes may be 600 (particle diameter 25 microns) to 1000 (particle diameter 15 microns) per unit area, for example, 800 to 1000. In the glass substrate, contaminants are formed on both the uneven surface and the smooth surface described above, and it is particularly difficult to remove the contaminants on the uneven surface. In order to remove this effectively, coarse particles with a mesh number of less than 600 can be used, but if the number of meshes of the abrasive is less than 600, the removal rate of contaminants may be fast, but the recycling efficiency may be very low due to damage to the glass substrate, and the number of meshes is 1000. If it is exceeded, damage to the glass substrate can be prevented, but the removal rate of contaminants is very slow, and the cleaning efficiency can be greatly reduced.

In this way, when the glass substrate is cleaned using the cleaning liquid composition for cleaning the glass substrate of the waste solar cell according to the present invention after polishing the glass substrate, the cleaning power is remarkably increased even when immersed for 30 seconds or less. Due to the nature of the contaminants formed on the glass substrate separated from the waste solar cell by the high-temperature oxidation process, after the polishing step using silicon carbide having a size of 700 to 900 microns, the glass substrate was added to the cleaning liquid composition for cleaning the glass substrate of the waste solar cell. In the case of immersion, the degree of acid penetration can be greatly increased.

Preparation Examples 1 to 6

With the composition of Table 1 below, a cleaning liquid composition for cleaning a glass substrate of a waste solar cell was prepared.

Manufacturing Example 1 Manufacturing Example 2 Manufacturing Example 3 Manufacturing Example 4 Manufacturing Example 5 Manufacturing Example 6 Ammonium difluoride 10 5 25 3 5 5 Hydrogen peroxide 10 - 10 10 - - Glass Etchant 1 - 50 - - 25 - Glass etchant 2 - - - - - 50 Sulfuric acid 20 15 20 20 15 15 water 60 30 45 67 30 30

GT-250MG4 was used as the glass etchant 1, and GT-2000 (acidity 3.2±0.5 M.O/1N NaOH) was used as the glass etchant 2.

Examples 1 to 6

A glass substrate of the same area separated from the waste solar cell by performing a high-temperature oxidation process of 400°C or higher was immersed in the cleaning liquid composition for cleaning the glass substrate of the waste solar cell according to Preparation Examples 1 to 6, and then treated with a neutralizing agent and washed with water. Thus, it is shown in Examples 1 to 6, respectively.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Soaking time (sec) 300 150 90 90 - - Total light transmittance for cleaning (%) 65 75 65 85 75 75 Light transmittance after cleaning (%) 90 90 X 90 X X

The immersion time is a record of the shortest immersion time at which the light transmittance is 90% or more among several experiments conducted with the composition of the cleaning liquid composition for cleaning a glass substrate of a waste solar cell according to the composition of each example, and the light transmittance is the corresponding It shows the light transmittance at the immersion time. On the other hand, the case where the light transmittance is not more than 90% is indicated by X. In the case of the solar cell glass substrate, since diffuse reflection treatment is performed on the surface of the glass substrate to increase the transmittance of the incident light, not only the straight transmittance but also It was measured by total light transmittance, which measures all the transmittance by scattering. Specifically, the total transmittance of visible light before and after treatment was compared using a Visible Spectrophotometer On-line Transmittance Measurement System; model HKL-02-OTMS (Korea Lab Product).

Example 7

In Example 7, a cleaning liquid composition for cleaning a glass substrate of a waste solar cell was not used, and contaminants on the surface of the glass substrate were removed only by a polishing process, which is a physical method. The area of the glass substrate is the same. In the polishing process, a conveyor mobile device was used, and the number of times the glass substrate was input was set to 3 times.

Silicon carbide with a mesh number of 800 was used as an abrasive, and a sponge-type and brush-type polishing method was used, and the running speed of the glass platen was set to 3 m/min to remove contaminants on the surface of the glass substrate.

The degree of change in light transmittance due to polishing and the surface state of the glass substrate after polishing are shown in Table 3 below.

Example 8

Contaminants on the surface of the glass substrate were removed in the same manner as in Example 7, except that silicon carbide having a mesh number of 1100 was used as the abrasive.

Table 3 shows the degree of change in light transmittance due to polishing and the surface state of the glass substrate after polishing.

Example 9

Contaminants on the surface of the glass substrate were removed in the same manner as in Example 7, except that silicon carbide having a mesh number of 550 was used as the abrasive.

Table 3 shows the degree of change in light transmittance due to polishing and the surface state of the glass substrate after polishing.

Example 7 Example 8 Example 9 Light transmittance before polishing (%) 65 65 65 Light transmittance after polishing (%) 77 71 84 Surface condition after polishing O O X

O: The glass substrate is smooth after polishing

X: Scratches on the surface of the glass substrate are visually observed, and irregularities are generated on the surface

In the case of Example 9, the surface of the glass substrate was damaged by the abrasive to form irregularities.

Examples 10 to 12

Example 10 is a case in which contaminants on the surface of the glass substrate were removed according to Example 1 after the glass substrate was polished in Example 7, and the glass substrate was polished according to Example 8. The case where contaminants on the surface of the glass substrate were removed according to Example 1 was described as Example 11, and the contaminants on the surface of the glass substrate were removed according to Example 2 after polishing the glass substrate according to Example 7 As Example 12, the results are shown in Table 4 below.

Example 10 Example 11 Example 12 Soaking time (sec) 30 60 35 Light transmittance before cleaning (%) 77 71 77 Light transmittance after cleaning (%) 90 90 90

The immersion time is a record of the shortest immersion time in which the light transmittance is 90% or more among several experiments conducted with the composition of the cleaning liquid composition for cleaning a glass substrate of a waste solar cell according to the composition of each example.

As described above, a detailed description of the present invention has been made by an embodiment with reference to the accompanying drawings, but the above-described embodiment has been described with reference to a preferred example of the present invention, so that the present invention is limited to the above embodiment. It should not be understood, and the scope of the present invention should be understood as the following claims and equivalent concepts.

For example, the drawings schematically show each component as a subject to aid understanding, and the thickness, length, number, etc. of each component shown may be different from the actual one in the progress of drawing creation. In addition, the material, shape, dimensions, etc. of each constituent element shown in the above embodiments are not particularly limited as an example, and various changes can be made without substantially departing from the effects of the present invention.

Claims (7)

A composition for cleaning a glass substrate separated from a waste solar cell by an oxidation process,
Ammonium difluoride ((NH ₄ )HF ₂ ) 5 to 20 parts by weight per 100 parts by weight of the composition, 10 to 20 parts by weight of acid, 5 to 20 parts by weight of hydrogen peroxide, and a diluent for cleaning glass substrates of waste solar cells Cleaning liquid composition.
delete A composition for cleaning a glass substrate separated from a waste solar cell by an oxidation process,
Ammonium difluoride per 100 parts by weight of the composition ((NH4)HF2) 5 to 20 parts by weight, acid 10 to 20 parts by weight, 30 to 60 parts by weight of a glass etchant and a diluent,
The glass etchant has an acidity of 11 MO/1N NaOH to 16 MO/1N NaOH, a cleaning liquid composition for cleaning a glass substrate of a waste solar cell.
delete A waste solar cell glass substrate cleaning method comprising immersing the waste solar cell glass substrate in the cleaning liquid composition for cleaning the waste solar cell glass substrate according to any one of claims 1 and 3.
The method of claim 5,
Before immersing the waste solar cell glass substrate in the waste solar cell glass substrate cleaning solution composition, further comprising polishing the glass substrate, a waste solar cell glass substrate cleaning method.
The method of claim 6,
Polishing the glass substrate is a waste solar cell glass substrate cleaning method using at least one of silicon carbide and aluminum oxide as an abrasive.