Intelligent cooling and caching method for silicon rods

Abstract

The invention discloses an intelligent silicon rod cooling and caching method, and belongs to a material caching method in the technical field of solar cell materials, and the technical scheme is as follows: S1, setting a caching library into a multi-stage cooling area, and enabling the temperature to be gradually reduced in the conveying direction; s2, a crystal bar is taken out of a furnace through a crystal taking vehicle with a heat insulation material and then transferred to a first-stage cooling area, and each stage of cooling area is provided with a fixed temperature interval; s3, the temperature of the crystal bar is measured at regular time through a temperature detection system in the multi-stage cooling area, and after the crystal bar reaches the lower limit value of the temperature interval, the crystal bar is automatically transferred to a next-stage cooling warehouse; according to the intelligent cooling and caching method for the silicon rod, multiple stages of cooling areas are arranged, and the problems that in the natural state, subfissure is likely to be generated due to fast cooling of a high-temperature section, and the efficiency is affected due to slow cooling of a low-temperature section are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cell materials, and in particular relates to an intelligent cooling and caching method for silicon rods. Background Art

[0002] Most single crystal silicon rods are manufactured using the Czochralski method, also known as the Czochralski method. This method uses the principle of melt condensation and crystallization drive. At the interface between solid and liquid, a phase change occurs from liquid to solid due to the drop in melt temperature. In this method, solid polysilicon melt is placed in a quartz crucible and heated to melt the polysilicon melt in the quartz crucible. After that, it goes through processes such as seeding, necking, shouldering, equalizing diameters, and finishing to finally complete the pulling of dislocation-free single crystal silicon rods.

[0003] When single crystal silicon rods come out of the furnace, the temperature can reach 300°C. The cooling method has a great impact on the quality and circulation efficiency of the product. The current industry generally uses natural air cooling for cooling, which has two shortcomings: First, the diameter of the silicon rod is constantly increasing, and the current mainstream products in the market have reached 300mm. The temperature difference between the high-temperature section of the crystal rod and the outside world is very large. An excessively fast cooling rate can easily cause a difference in the surface temperature and the core temperature of the crystal rod, leading to internal stress. For the tail of the silicon rod with relatively weak bearing capacity or areas with other defects, cracks are likely to develop, resulting in waste of silicon rods; second, the cooling rate of the silicon rod in the low-temperature section is very slow, affecting the circulation efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a silicon rod intelligent cooling and caching method, which sets up multi-level cooling zones to solve the problem that in the natural state, the high-temperature section cools quickly and easily causes hidden cracks, while the low-temperature section cools slowly and affects efficiency.

[0005] The object of the present invention is achieved by providing a silicon rod intelligent cooling and caching method, comprising the following steps:

[0006] S1. Set the buffer store as a multi-level cooling zone, and make the temperature decrease step by step in the conveying direction;

[0007] S2. Use a crystal retrieval vehicle with heat insulation material to remove the crystal ingot from the furnace and transfer it to the primary cooling zone. Each cooling zone is set with a fixed temperature range;

[0008] S3. The temperature of the crystal ingot is measured regularly by the temperature detection system in the multi-stage cooling zone. When the crystal ingot reaches the lower limit of the temperature range, it is automatically transferred to the next stage cooling storage.

[0009] Furthermore, the multi-stage cooling zone is configured as a high-temperature cooling zone, a natural cooling zone and an air-cooling zone which are connected in sequence. The high-temperature cooling zone is in a closed state, the natural cooling zone is connected to the factory building and is a fully open system. The air-cooling zone is in a closed state and is cooled by air conditioning.

[0010] Furthermore, the temperature of the high-temperature cooling zone is regulated by the residual heat of the crystal rod and the air-conditioning system.

[0011] Furthermore, the multi-stage cooling zone is provided with four levels, namely, the high temperature zone is the first cooling zone and the second cooling zone, the natural cooling zone is the third cooling zone, and the air-conditioning cold air zone is the fourth cooling zone.

[0012] Furthermore, the temperature range of each zone in the four-stage cooling zone is established.

[0013] (1) Model establishment: Measure the relationship between the cooling time and temperature of the crystal rod in the natural state, draw a scatter plot, and obtain the fitting function relationship: T = 285.62t-0.911, where R 2 =0.977>0.7;

[0014] (2) Calculate the relationship between cooling rate and temperature difference: Use the functional relationship to calculate the relationship between temperature difference, cooling rate and temperature difference. The formula is: In the formula is the cooling rate, T is the silicon rod temperature, and T0 is the ambient temperature;

[0015] (3) Divide the intervals: When the temperature of the crystal rod out of the furnace is set to a℃ and the ambient temperature is set to b℃, the maximum cooling rate requirement is set to 200℃ / h. When the temperature difference between the crystal rod and the ambient temperature is less than 20℃, the cooling rate is less than 10℃ / h. Considering the influence of the cooling rate, the crystal rod enters the next interval when the temperature difference between the crystal rod and the ambient temperature is less than 20℃.

[0016] Furthermore, when the temperature difference between the crystal rod and the environment is less than 15° C., the crystal rod enters the next interval.

[0017] Furthermore, the temperature of the first-stage cooling zone is set to 164°C, the temperature of the second-stage cooling zone is set to 80°C, the temperature of the third-stage cooling zone is set to 40°C, and the temperature of the fourth-stage cooling zone is set to 20°C.

[0018] Furthermore, the buffer cooling time of the multi-stage cooling zone is less than 10 hours.

[0019] The beneficial effects of the present invention are embodied in:

[0020] In the present invention, multi-stage cooling zones are set up to solve the problem that under natural conditions, the high-temperature section cools quickly and easily causes hidden cracks, while the low-temperature section cools slowly and affects efficiency. By using historical cooling data, the temperature range settings of each level of cooling storage area are intelligently corrected while ensuring the maximum cooling rate, thereby maximizing the circulation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly describes the drawings required for the specific embodiments or the description of the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0022] Figure 1 This is a flow chart of the silicon rod intelligent cooling and caching method of the present invention.

[0023] Figure 2 This is a temperature-time scatter diagram of the crystal rod cooling in the natural state of the present invention. DETAILED DESCRIPTION

[0024] The following embodiments of the technical solution of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only examples and are not intended to limit the scope of protection of the present invention.

[0025] It should be noted that, unless otherwise specified, the technical or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0026] A silicon rod intelligent cooling and caching method comprises the following steps:

[0027] S1. The buffer is set as a multi-stage cooling zone, and the temperature is gradually reduced in the conveying direction; the multi-stage cooling zone is set to gradually reduce in the conveying direction to realize the conveying processing of the cooling buffer of the silicon rod;

[0028] S2. A crystal retrieval vehicle with heat-insulating material is used to remove the crystal rod from the furnace and transfer it to the first-level cooling zone. Each cooling zone is set with a fixed temperature range. To ensure that the crystal rod is removed from the furnace, temperature dissipation during the removal process is avoided, and the established temperature cannot be effectively controlled, thereby affecting the established temperature of the cache. Then, when the crystal rod is taken out of the furnace, a crystal retrieval vehicle with heat-insulating material is used to remove and place it. In this way, the initial temperature of the crystal rod can be controlled, ensuring that multi-level cache operations can be achieved within the established temperature range.

[0029] S3. The temperature of the crystal ingot is measured regularly by the temperature detection system in the multi-stage cooling zone. When the crystal ingot reaches the lower limit of the temperature range, it is automatically transferred to the next stage cooling storage. In order to ensure that the temperature range of the crystal ingot can be accurately controlled in each stage cooling zone, it is necessary to set up a temperature detection system in the corresponding cooling zone to regularly detect the temperature of the placed crystal ingot, so as to realize the next step of transportation or operation, thereby improving the accuracy of the multi-stage cooling operation process.

[0030] In a specific preferred embodiment, the multi-stage cooling zone is configured as a high-temperature cooling zone, a natural cooling zone and an air-cooling zone connected in sequence. The high-temperature cooling zone is in a closed state, the natural cooling zone is connected to the factory building and is a fully open system. The air-cooling zone is in a closed state and is cooled by air conditioning.

[0031] Preferably, the temperature of the high-temperature cooling zone is controlled by the residual heat of the crystal rod and an air-conditioning system.

[0032] In a specific preferred embodiment, the multi-stage cooling zone is provided with four levels, namely, the high temperature zone is the first cooling zone and the second cooling zone, the natural cooling zone is the third cooling zone, and the air-conditioning cold air zone is the fourth cooling zone.

[0033] It is understandable that the temperature range of each zone is established for the four-stage cooling zone.

[0034] (1) Model establishment: Measure the relationship between the cooling time and temperature of the crystal rod in the natural state, draw a scatter plot, and obtain the fitting function relationship: T = 285.62t-0.911, where R 2 =0.977>0.7;

[0035] (2) Calculate the relationship between cooling rate and temperature difference: Use the functional relationship to calculate the relationship between temperature difference, cooling rate and temperature difference. The formula is: In the formula is the cooling rate, T is the silicon rod temperature, and T0 is the ambient temperature;

[0036] (3) Divide the intervals: When the temperature of the crystal rod out of the furnace is set to a℃ and the ambient temperature is set to b℃, the maximum cooling rate requirement is set to 200℃ / h. When the temperature difference between the crystal rod and the ambient temperature is less than 20℃, the cooling rate is less than 10℃ / h. Considering the influence of the cooling rate, the crystal rod enters the next interval when the temperature difference between the crystal rod and the ambient temperature is less than 20℃.

[0037] In a specific preferred embodiment, the crystal rod enters the next interval when the temperature difference between the crystal rod and the environment is less than 15°C.

[0038] In a specific preferred embodiment, the temperature of the primary cooling zone is set to 164°C, the temperature of the secondary cooling zone is set to 80°C, the temperature of the tertiary cooling zone is set to 40°C, and the temperature of the quaternary cooling zone is set to 20°C.

[0039] In a specific preferred embodiment, the buffer cooling time of the multi-stage cooling zone is less than 10 hours.

[0040] Example 1

[0041] A silicon rod intelligent cooling and caching method comprises the following steps:

[0042] S1. The buffer is set as a multi-stage cooling zone, and the temperature is gradually reduced in the conveying direction; the multi-stage cooling zones are set to gradually reduce in the conveying direction to realize the conveying processing of the cooling buffer of the silicon rod; the multi-stage cooling zone is set to be connected to a high-temperature cooling zone, a natural cooling zone and an air cooling zone in sequence, the high-temperature cooling zone is in a closed state, the natural cooling zone is connected to the factory building and is a fully open system, and the air cooling zone is in a closed state and is cooled by air conditioning; the temperature of the high-temperature cooling zone is controlled by the residual heat of the crystal rod and the air conditioning system; the multi-stage cooling zone is set to four levels, namely, the high-temperature zone is the first cooling zone and the second cooling zone, the natural cooling zone is the third cooling zone, and the air conditioning cold air zone is the fourth cooling zone;

[0043] S2. A crystal retrieval vehicle with heat-insulating material is used to remove the crystal rod from the furnace and transfer it to the first-level cooling zone. Each cooling zone is set with a fixed temperature range. To ensure that the crystal rod is removed from the furnace, temperature dissipation during the removal process is avoided, and the established temperature cannot be effectively controlled, thereby affecting the established temperature of the cache. Then, when the crystal rod is taken out of the furnace, a crystal retrieval vehicle with heat-insulating material is used to remove and place it. In this way, the initial temperature of the crystal rod can be controlled, ensuring that multi-level cache operations can be achieved within the established temperature range.

[0044] S3. The temperature of the crystal ingot is measured regularly by the temperature detection system in the multi-stage cooling zone. When the crystal ingot reaches the lower limit of the temperature range, it is automatically transferred to the next stage cooling storage. In order to ensure that the temperature range of the crystal ingot can be accurately controlled in each stage cooling zone, it is necessary to set up a temperature detection system in the corresponding cooling zone to regularly detect the temperature of the placed crystal ingot, so as to realize the next step of transportation or operation, thereby improving the accuracy of the multi-stage cooling operation process.

[0045] Establish the temperature range of each zone in the four-level cooling zone.

[0046] (1) Model establishment: Measure the relationship between the cooling time and temperature of the crystal rod in the natural state, draw a scatter plot, and obtain the fitting function relationship: T = 285.62t-0.911, where R 2 =0.977>0.7;

[0047] Table 1 Crystal ingot cooling record under natural state

[0048]

[0049]

[0050] (2) Calculate the relationship between cooling rate and temperature difference: Use the functional relationship to calculate the relationship between temperature difference, cooling rate and temperature difference. The formula is: In the formula is the cooling rate, T is the silicon rod temperature, and T0 is the ambient temperature;

[0051] (3) Divide the intervals: Set the ingot temperature out of the furnace to 300°C. When the ambient temperature is 40°C, set the maximum cooling rate requirement to 200°C / h. When the difference between the ingot temperature and the ambient temperature is less than 20°C, the cooling rate is less than 10°C / h. Considering the influence of the cooling rate, enter the next interval when the difference between the ingot temperature and the ambient temperature is less than 20°C.

[0052] Thus, the temperature of the primary cooling zone can be set to 164°C, the temperature of the secondary cooling zone to 80°C, the temperature of the tertiary cooling zone to 40°C, and the temperature of the quaternary cooling zone to 20°C.

[0053] Table 2 Intelligent cache temperature range division table

[0054]

[0055]

[0056] Comparison of results: The maximum cooling rate for natural cooling is greater than 288°C / h. The intelligent cooling bank can adjust the maximum cooling rate, calculated here as 200°C / h. Cooling to 40°C requires 8.65 hours under natural conditions, but only 3.06 hours under the intelligent buffer, significantly improving efficiency. It should be noted that the temperature in the single crystal test room is relatively high. For constant temperature workshops or cold regions, the temperature range and temperature control equipment configuration of the storage area can be adjusted according to demand.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A silicon rod intelligent cooling and caching method, characterized in that: The steps include: S1. Set the buffer store as a multi-level cooling zone, and make the temperature decrease step by step in the conveying direction; S2. Use a crystal retrieval vehicle with heat insulation material to remove the crystal ingot from the furnace and transfer it to the primary cooling zone. Each cooling zone is set with a fixed temperature range; S3. The temperature of the crystal ingot is measured regularly by the temperature detection system in the multi-stage cooling zone. When the crystal ingot reaches the lower limit of the temperature range, it is automatically transferred to the next stage cooling storage.

2. The silicon rod intelligent cooling and caching method according to claim 1, characterized in that: The multi-stage cooling zone is configured as a high-temperature cooling zone, a natural cooling zone and an air cooling zone connected in sequence. The high-temperature cooling zone is in a closed state. The natural cooling zone is connected to the factory building and is a fully open system. The air cooling zone is in a closed state and uses air conditioning for cooling.

3. The silicon rod intelligent cooling and caching method according to claim 2, characterized in that: The temperature of the high-temperature cooling zone is regulated by the residual heat of the crystal ingot and the air conditioning system.

4. The silicon rod intelligent cooling and caching method according to claim 1, wherein: The multi-stage cooling zone is provided with four stages, namely, the high temperature zone is the first-stage cooling zone and the second-stage cooling zone, the natural cooling zone is the third-stage cooling zone, and the air-conditioning cold wind zone is the fourth-stage cooling zone.

5. The silicon rod intelligent cooling and caching method according to claim 1, wherein: Establish the temperature range of each zone in the four-level cooling zone. (1) Model establishment: Measure the relationship between the cooling time and temperature of the crystal rod in the natural state, draw a scatter plot, and obtain the fitting function relationship: T = 285.62t-0.911, where R 2 =0.977>0.7; (2) Calculate the relationship between cooling rate and temperature difference: Use the functional relationship to calculate the relationship between temperature difference, cooling rate and temperature difference. The formula is: In the formula is the cooling rate, T is the silicon rod temperature, and T0 is the ambient temperature; (3) Divide the intervals: When the temperature of the crystal rod out of the furnace is set to a℃ and the ambient temperature is set to b℃, the maximum cooling rate requirement is set to 200℃ / h. When the temperature difference between the crystal rod and the ambient temperature is less than 20℃, the cooling rate is less than 10℃ / h. Considering the influence of the cooling rate, the crystal rod enters the next interval when the temperature difference between the crystal rod and the ambient temperature is less than 20℃.

6. The silicon rod intelligent cooling and caching method according to claim 5, characterized in that: When the temperature difference between the crystal rod and the environment is less than 15°C, the crystal rod enters the next interval.

7. The silicon rod intelligent cooling and caching method according to claim 5, characterized in that: The temperature of the first-stage cooling zone is set to 164°C, the temperature of the second-stage cooling zone is set to 80°C, the temperature of the third-stage cooling zone is set to 40°C, and the temperature of the fourth-stage cooling zone is set to 20°C.

8. The silicon rod intelligent cooling and caching method according to claim 5, characterized in that: The buffer cooling time of the multi-stage cooling zone is less than 10 hours.

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