CN105063757B - A kind of hypoxemia spraying method - Google Patents

Abstract

The application discloses a low-oxygen spraying method, comprising: using ceramic viscose and silica sol to make an adhesive, the weight of the ceramic viscose in the adhesive is greater than the weight of the silica sol; mixing with silicon nitride powder, adding the binder, and stirring to obtain a prepared coating; using purified compressed air to spray the coating on the inner wall of the crucible. The above-mentioned low-oxygen spraying method that the application provides, owing to utilize vitrified viscose and silica sol to make adhesive, the weight of described vitrified viscose in the described adhesive is greater than the weight of described silica sol, therefore can reduce spray coating In order to reduce the oxygen content in the silicon ingot and enhance the light attenuation effect of the cell.

Description

A kind of hypoxic spraying method

technical field

The invention relates to the field of photovoltaic technology, in particular to a low-oxygen spraying method.

Background technique

The competition of polycrystalline technology is actually the competition of silicon ingot quality. Thermal spraying is an important step in the manufacture of silicon ingots.

The current heating spray process uses silicon nitride, water, silica sol, and ceramic binders. One process is: mix 1800ml of pure water and 600g of silicon nitride powder evenly, add 200ml of silica sol and 5g of ceramic binder while stirring continuously, and stir for a few minutes, then use purified silicon liquid coating Compressed air for spraying, gun pressure of 20psi-40psi, spraying distance of 25cm-30cm, positioning landing crucible width of 15-20cm, spraying thickness of about 0.01mm, crucible spraying temperature of 45-60°C, and then sintering .

However, in the above-mentioned heating spraying process, due to the high oxygen content in the silicon dioxide of the silica sol, the resulting sprayed coating has a high oxygen content and poor compactness. Diffusion in the ingot, resulting in high oxygen content in the silicon ingot, which reduces the light decay effect of the cell.

Contents of the invention

In order to solve the above problems, the present invention provides a low-oxygen spraying method, which can reduce the oxygen content in the sprayed layer, so as to reduce the oxygen content in the silicon ingot and enhance the light attenuation effect of the cell.

A kind of low-oxygen spraying method provided by the invention comprises:

Utilize ceramic viscose and silica sol to make adhesive, the weight of ceramic viscose in described adhesive is greater than the weight of described silica sol;

Mix pure water and silicon nitride powder, add the binder, and stir to obtain the prepared coating;

The paint is sprayed onto the inner wall of the crucible using purified compressed air.

Preferably, in the above low-oxygen spraying method, the ceramic glue includes polyvinyl alcohol and polyurethane.

Preferably, in the above low-oxygen spraying method, the proportion of the ceramic adhesive in the adhesive is set to be 60% to 80%.

Preferably, in the above-mentioned low-oxygen spraying method, the pure water and silicon nitride powder are mixed, the binder is added, and stirred as follows: 1800ml of the pure water and 700g of the silicon nitride powder Mix well, and add 500ml of the adhesive, and stir for 20 minutes to 50 minutes.

Preferably, in the above low-oxygen spraying method, the use of purified compressed air to spray the paint on the inner wall of the crucible is: using a spray gun with a pressure of 20 psi to 40 psi to spray the paint on the inner wall of the crucible at a distance of 25 cm to 30 cm. The paint is sprayed on the inner wall of the crucible, and the width of the crucible is 15cm to 20cm.

Preferably, in the above low-oxygen spraying method, the spraying temperature is controlled within a range of 80°C to 100°C.

Preferably, in the above low-oxygen spraying method, the spraying thickness of the paint is controlled to be in the range of 0.2 mm to 0.5 mm.

Preferably, in the above low-oxygen spraying method, after spraying the paint on the inner wall of the crucible, the method further includes: sintering the crucible.

The above-mentioned low-oxygen spraying method provided by the present invention, owing to utilize ceramic viscose and silica sol to make adhesive, the weight of the ceramic viscose in the described adhesive is greater than the weight of described silica sol, therefore can reduce the Oxygen content to reduce the oxygen content in the silicon ingot and enhance the light decay effect of the cell.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

Fig. 1 is the schematic diagram of a kind of hypoxic spraying method that the embodiment of the present application provides;

Fig. 2 is a schematic diagram of another low-oxygen spraying method provided by the embodiment of the present application.

detailed description

The core idea of the present invention is to provide a low-oxygen spraying method to reduce the oxygen content in the sprayed layer, so as to reduce the oxygen content in the silicon ingot and enhance the light attenuation effect of the cell.

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

A low-oxygen spraying method provided in the embodiment of the present application is shown in FIG. 1 , and FIG. 1 is a schematic diagram of a low-oxygen spraying method provided in the embodiment of the present application. The method comprises the steps of:

S1: Using ceramic viscose and silica sol to make an adhesive, the weight of the ceramic viscose in the adhesive is greater than the weight of the silica sol;

Compared with the high content of silica sol in the paint in the prior art, and the high oxygen content of silicon dioxide in the silica sol, resulting in high oxygen content of the produced silicon ingot, and the key point of this step in this embodiment is to make the bonding In the composition of the agent, the weight of silica sol is less than that of ceramic viscose, and ceramic viscose will not bring oxygen, thereby avoiding the phenomenon that the oxygen content of the silicon ingot finally produced is high, and the sprayed coating in the prior art is sticky The combined force is weak and the powder is easy to fall off, which makes the silicon ingot stick to the pan during the stripping process, so that the silicon ingot cannot maintain its integrity and reduces the crystallization rate of the silicon ingot. In this embodiment, ceramic viscose and silica sol are used together, This problem can be solved, the effect of enhancing the adhesive force can be realized, the sticking to the pan can be avoided, and the crystallization rate of the silicon ingot can be improved.

S2: Mix pure water and silicon nitride powder, add the binder, and stir to obtain the prepared coating;

Among them, silicon nitride powder is an important structural ceramic material. It is a superhard substance with lubricity and wear resistance. It will not react with other inorganic acids except hydrofluoric acid and has strong corrosion resistance. , anti-oxidation at high temperature, but also resistant to cold shock, heated to above 1000 ℃ in the air, rapid cooling and then rapid heating, it will not break. In this embodiment, the silicon nitride powder is sprayed on the surface of the crucible, and bonded to the surface of the crucible with an adhesive to form a coating, so that the quartz crucible and silicon are isolated from each other at high temperatures, thereby preventing liquid silicon from reacting with the quartz crucible Cause the crucible to break, and finally ensure the integrity of the silicon ingot stripping film after cooling.

S3: Using purified compressed air to spray the paint on the inner wall of the crucible.

In this step, the adhesion of the coating can be improved by controlling parameters such as spraying temperature and spraying thickness.

The above-mentioned low-oxygen spraying method that the embodiment of the present application provides, owing to utilize ceramic viscose and silica sol to make adhesive, the weight of the ceramic viscose in described adhesive is greater than the weight of described silica sol, therefore can reduce the spray coating In order to reduce the oxygen content in the silicon ingot and enhance the light attenuation effect of the cell.

It should be noted that, in the above step S1, the ceramic glue can include polyvinyl alcohol and polyurethane, and this organic component will not introduce oxygen into the coating, thereby further reducing the oxygen content in the silicon ingot, and can enhance spray coating layer adhesion. Further, the proportion of the ceramic viscose in the adhesive can be set to be 60% to 80%, correspondingly, the proportion of the silica sol is 20%-40%, it can be seen that the ceramic viscose It accounts for most of the binder, so as to achieve the purpose of reducing the oxygen content of the coating.

A specific implementation is described below, as shown in FIG. 2 , which is a schematic diagram of another low-oxygen spraying method provided in the embodiment of the present application. The method comprises the steps of:

A1: Utilize ceramic viscose and silica sol to make adhesive, the weight of the ceramic viscose in described adhesive is greater than the weight of described silica sol;

A2: Mix 1800ml of the pure water and 700g of the silicon nitride powder, add 500ml of the binder, and stir for 20 to 50 minutes to obtain the prepared coating;

A3: using a spray gun with a pressure of 20psi to 40psi, spray the coating on the inner wall of the crucible at a position of 25cm to 30cm away from the inner wall of the crucible, and position the width of the crucible to be 15cm to 20cm;

Wherein, the temperature range of controlling the spraying is 80°C to 100°C. Compared with the prior art, the spraying temperature in this embodiment is higher, which can evaporate excess water as much as possible, and prevent the sprayed layer from being too wet to flow down. The phenomenon of uneven spray coating and decreased adhesion.

Moreover, the spraying thickness of the coating is controlled to be in the range of 0.2mm to 0.5mm. Compared with the prior art, the spraying thickness in this embodiment is increased, so that the bonding effect is better, and the crucible can be better blocked. Oxygen enters the silicon ingot.

A4: Sintering the crucible.

Among them, the purpose of sintering is to increase the crystallinity of the coating and avoid the coating falling off caused by internal stress, thereby improving the toughness and adhesion of the coating.

From the above description, it can be seen that the low-oxygen spraying method provided by the embodiment of the present application can reduce the oxygen content in the sprayed layer, so as to reduce the oxygen content in the silicon ingot, enhance the light attenuation effect of the cell, and enhance the adhesion , better resistance, the oxygen in the crucible enters the silicon ingot, and it can also prevent the coating from falling off.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (7)

1. a low oxygen spraying method, is characterized in that, comprises: Utilize ceramic viscose and silica sol to make adhesive, the weight of described ceramic viscose in described adhesive is greater than the weight of described silica sol, the proportion that described ceramic viscose occupies in described adhesive 60% to 80%; Mix pure water and silicon nitride powder, add the binder, and stir to obtain the prepared coating; The paint is sprayed onto the inner wall of the crucible using purified compressed air. 2. The hypoxic spraying method according to claim 1, characterized in that, the ceramic viscose comprises polyvinyl alcohol and polyurethane. 3. The hypoxic spraying method according to any one of claims 1-2, characterized in that, mixing the pure water and silicon nitride powder, adding the binder, and stirring as follows: 1800ml The pure water and 700 g of the silicon nitride powder were mixed evenly, and 500 ml of the binder was added, and stirred for 20 minutes to 50 minutes. 4. The hypoxic spraying method according to claim 3, characterized in that said using purified compressed air to spray the coating on the inner wall of the crucible is: using a spray gun with a pressure of 20psi to 40psi to spray the paint at a distance of 25cm from the inner wall of the crucible. To the position of 30cm, spray the coating on the inner wall of the crucible, and position the width of the crucible to be 15cm to 20cm. 5. The low-oxygen spraying method according to claim 4, characterized in that the spraying temperature is controlled in a range of 80°C to 100°C. 6. The hypoxic spraying method according to claim 5, characterized in that the spraying thickness of the coating is controlled to be in the range of 0.2mm to 0.5mm. 7 . The low-oxygen spraying method according to claim 6 , further comprising: sintering the crucible after spraying the paint on the inner wall of the crucible.