A rapid cooling type silicon ingot mold and a pouring system thereof

Abstract

The utility model relates to ingot mould casting technical field especially, relates to a kind of rapid cooling type silicon ingot mould and its pouring system, the silicon ingot mould includes ingot mould body and the mould cavity of being located at its one side, ingot mould body is cuboid structure, and mould cavity is inverted square platform shape with edge fillet rounding. S-shaped cooling pipe is equipped in ingot mould body, both ends are located in the same side surface, for passing into cooling medium to accelerate heat dissipation. Pouring system includes sprue, cross gate, ceramic tube, inner gate and riser, pouring is poured using inverted bottom pouring mode, avoid mould cavity inner wall defect. The utility model realizes silicon ingot rapid and uniform cooling by optimizing ingot mould structure and cooling system, improve production efficiency and product quality, applicable to silicon ingot casting field.

Description

Technical Field

[0001] This utility model relates to the field of ingot casting technology, and in particular to a rapid cooling silicon ingot mold and its casting system. Background Technology

[0002] Silicon ingot casting is a crucial link in the photovoltaic industry chain, and its quality directly affects the performance and yield of subsequent silicon wafers. Traditional silicon ingot molds are mostly made of cast iron or steel, with mold cavities typically designed in a rectangular or trapezoidal shape. The gating system is simple, and cooling mainly relies on natural cooling or external air cooling. Due to the large shrinkage rate and concentrated thermal stress during the solidification process of silicon ingots, defects such as shrinkage cavities, cracks, and deformation are prone to occur, affecting the integrity and performance of the silicon ingots.

[0003] As the photovoltaic industry places increasing demands on silicon ingot quality, traditional silicon ingot molds are gradually proving inadequate in terms of cooling efficiency and casting quality. This is particularly true in the production of large, flat silicon ingots, where natural cooling is time-consuming and results in uneven temperature distribution, leading to coarse internal structures and severe component segregation, thus reducing the mechanical and electrical properties of the ingot. Furthermore, an improperly designed gating system can cause unstable melt flow and oxide inclusions, further impacting ingot quality.

[0004] Currently, although some improved silicon ingot molds use water cooling or air cooling to accelerate cooling, problems such as uneven cooling, complex mold structure, and high maintenance costs still exist. Utility Model Content

[0005] To address the aforementioned technical problems, this utility model provides a rapid-cooling silicon ingot mold and its casting system. It employs a combination of a built-in S-shaped cooling pipe and an inverted bottom-pouring casting system, solving the problems of uneven cooling, shrinkage cavities, cracks, and low casting efficiency associated with traditional silicon ingot molds. Specifically, this is achieved through the following technical solutions.

[0006] This utility model provides a rapid cooling silicon ingot mold, including an ingot mold body with a cuboid structure and a mold cavity formed on one side surface of the ingot mold body. The mold cavity is located on the surface where the length and width of the ingot mold body are located, and the outline of the mold cavity is an inverted square platform with rounded edges. The ingot mold body is equipped with a cooling pipe with an S-shaped trajectory inside. The two ports of the cooling pipe are located on the same side of the ingot mold body, where the length and height are located. The cooling pipe is used to introduce a cooling medium to achieve silicon ingot cooling. The sides of the ingot mold body where the length and height are located are provided with several lifting shafts for hoisting and transfer, and the two lifting shafts are symmetrical about the center of the ingot mold body.

[0007] Preferably, the ratio of the length, width, and height of the ingot mold body is 45-55:41-51:8-10, and the ratio of the thickness of the mold cavity to the height of the ingot mold body is 1:3. The bottom side of the mold cavity is provided with a first rounded corner, and the top side is provided with a second rounded corner. The first rounded corner and the second rounded corner are tangent, and the radius of the first rounded corner is twice the radius of the second rounded corner.

[0008] Preferably, the cooling pipe includes an arc segment and a straight segment, the arc segment is a semi-circular trajectory, the trajectory of the cooling pipe is located in the same horizontal plane, the horizontal plane is parallel to the bottom surface of the ingot mold body, and the horizontal plane is the plane of symmetry between the bottom surface of the ingot mold body and the bottom surface of the mold cavity; The cooling pipe is a high-strength seamless steel pipe with an outer diameter to height ratio of 1:7.5 to 8.5, a wall thickness of 5 to 7 mm, and an arc segment trajectory diameter to length ratio of 3:23 to 27.

[0009] Preferably, the surface of the cooling pipe is thermally sprayed with an Al2O3 coating with a thickness of ≥200μm.

[0010] Preferably, the longitudinal edges of the ingot mold body are rounded.

[0011] This utility model also provides a casting system for a rapid-cooling silicon ingot mold, used for casting the aforementioned rapid-cooling silicon ingot mold. The casting system includes a sprue, a gating system, several ceramic tubes, several ingates, and several risers, and uses an inverted bottom pouring method for casting. The sprue is vertically arranged and close to the side where the width and height of the ingot mold are located. The bottom of the sprue is connected to the middle of the horizontal sprue. The side of the horizontal sprue is connected to the first end of several ceramic tubes along its length. The side of the ceramic tubes is connected to the first end of several ingates. The second end of the ingates is connected to the ingot mold. The riser is vertically located at the top of the ingot mold and connected to the ingot mold, and is used for filling and shrinking during the silicon ingot cooling process.

[0012] Preferably, the ratio of the cross-sectional area of ​​the sprue, the runner, and the ceramic tube is 105-121:95-105:12-13, the ratio of the diameter of the sprue to the height of the ingot mold is 4:15, and the inner diameter of the ceramic tube is equal to the diameter of the ingate.

[0013] Preferably, the number of ceramic tubes is 8, and the number of internal gating channels connected to each ceramic tube is two; The number of risers is 12, and the risers are evenly distributed on the upper end of the mold body.

[0014] Preferably, it also includes several E-shaped hangers, one side of which is used to clamp the straight section of the cooling pipe, and the other side is fixed to the upper mold; The number of hangers installed on the straight section of each cooling pipe is equal, and the hangers are evenly distributed along the length of the straight section of the cooling pipe.

[0015] Preferably, the second end of the ingate is not connected to the inner wall of the mold cavity.

[0016] After adopting the above technical solution, the beneficial effects of this utility model are: 1. This utility model designs the silicon ingot into a flat shape and optimizes the rounded corner structure of the mold cavity, which significantly increases the heat dissipation area, facilitates the rapid cooling and shaping of the silicon ingot, and allows the silicon ingot to shrink freely along the length and width directions during the condensation process, reducing stress concentration and improving demolding efficiency.

[0017] 2. The silicon ingot mold has a reasonable arrangement of built-in S-shaped cooling pipes, which combine arc-shaped and straight sections to ensure uniform flow of the cooling medium and achieve synchronous cooling of all parts of the silicon ingot, avoiding quality problems caused by excessive local temperature differences.

[0018] 3. The gating system adopts an inverted bottom pouring method, combined with a multi-channel ceramic tube and ingate design, which allows the molten metal to fill the mold smoothly, reduces eddies and oxidation, and the uniform arrangement of risers helps to compensate for shrinkage, effectively prevents shrinkage cavities and casting defects, and improves the overall quality of silicon ingots.

[0019] 4. The surface of the cooling pipe is coated with an aluminum oxide coating to enhance its heat resistance and insulation, protect the cooling pipe from corrosion by high-temperature molten metal during the casting process, extend the service life of the mold, and ensure a long-lasting and stable cooling effect. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A three-dimensional view of a rapid-cooling silicon ingot mold; Figure 2 for Figure 1 A top-down perspective view; Figure 3 for Figure 2 A longitudinal sectional view; Figure 4 for Figure 1 A three-dimensional view of the gating system of a rapid-cooling silicon ingot mold; Figure 5 for Figure 4 Side view; Figure 6 for Figure 4 A 3D view of the middle part.

[0022] Explanation of reference numerals in the attached figures: 101-Ingot mold body, 102-Mold cavity, 103-First fillet, 104-Second fillet, 105-Hanging shaft, 106-Cooling pipe; 201-Straight runner, 202-Horizontal runner, 203-Ceramic tube, 204-Ingate, 205-Riser, 206-Hanger. Detailed Implementation

[0023] The features and exemplary embodiments of various aspects of this utility model will now be described in detail. To make the objectives, technical solutions, and advantages of this utility model clearer, the following description, in conjunction with the accompanying drawings and specific embodiments, will provide a further detailed description. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit it. Those skilled in the art will recognize that this utility model can be implemented without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of this utility model by illustrating examples of it.

[0024] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this utility model. It should also be noted in the description of this utility model that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0025] This utility model provides a rapid cooling silicon ingot mold, see [link to relevant documentation]. Figure 1 , Figure 2 , Figure 3 The rapid cooling silicon ingot mold includes an ingot mold body 101 and a mold cavity 102 formed on one side surface of the ingot mold body 101. The ingot mold body 101 has a cuboid structure and its length, width and height ratio is 45-55:41-51:8-10. The mold cavity 102 is located on the surface where the length and width of the ingot mold body 101 are located.

[0026] The mold cavity 102 has an outline shape of an inverted square with rounded edges. The bottom side of the mold cavity 102 is provided with a first rounded corner 103, and the top side of the mold cavity 102 is provided with a second rounded corner 104. The first rounded corner 103 and the second rounded corner 104 are tangent to each other, and the radius of the first rounded corner 103 is twice the radius of the second rounded corner 104.

[0027] The longitudinal edges of the ingot mold body 101 are rounded.

[0028] The ratio of the thickness of the mold cavity 102 to the height of the ingot mold body 101 is 1:3.

[0029] The ingot mold body 101 and mold cavity 102 of the above structure make the cast silicon ingot flat and the edges and corners rounded and smooth. On the one hand, the flat silicon ingot has a larger heat dissipation area, which is convenient for rapid cooling and shaping. On the other hand, the structure allows the silicon ingot to shrink freely along the length and width directions during the condensation process, reducing constraints and facilitating the separation of the silicon ingot from the silicon ingot mold.

[0030] The length and height of the ingot mold body 101 are provided with a number of hanging shafts 105, and the number of hanging shafts 105 on each side is equal. The hanging shafts 105 on the two sides are symmetrical about the center of the ingot mold body 101.

[0031] The symmetrically arranged lifting shafts 105 on the side facilitate the hoisting and transfer of the ingot mold body 101, providing convenience for the actual production process.

[0032] The mold body 101 is also provided with an S-shaped cooling pipe 106 inside. The cooling pipe 106 is divided into an arc segment and a straight segment. The arc segment is a semi-circular trajectory. The two ends of the cooling pipe 106 are located on the same side of the mold body 101, and this side is the side where the length and height of the mold body 101 are located.

[0033] The ratio of the outer diameter of the cooling pipe 106 to the height of the ingot mold body 101 is 1:7.5 to 8.5, the wall thickness of the cooling pipe 106 is 5 to 7 mm, and the ratio of the diameter of the arc segment trajectory of the cooling pipe 106 to the length of the ingot mold body 101 is 3:23 to 27.

[0034] The trajectory of the cooling pipe 106 lies in the same horizontal plane, which is parallel to the bottom surface of the mold body 101, and this horizontal plane is the plane of symmetry between the bottom surface of the mold body 101 and the bottom surface of the mold cavity 102.

[0035] Among them, cooling pipe 106 is a high-strength seamless steel pipe.

[0036] During the production process, when the silicon ingot is cooled, a cooling medium is injected into the cooling pipe 106. Through the heat exchange between the cooling pipe 106 and the inside of the ingot mold 101, the excess heat is carried away by the cooling medium, thereby achieving rapid cooling of the ingot mold 101 and the ingot mold, and achieving rapid cooling and shaping of the silicon ingot.

[0037] The above embodiment ensures that the cooling pipe 106 is evenly and reasonably distributed inside the ingot mold body 101 by limiting the ratio of the trajectory diameter of the arc segment of the cooling pipe 106 to the length of the ingot mold body 101, thereby avoiding large regional temperature differences caused by uneven heat dissipation and achieving uniform cooling of various parts of the silicon ingot.

[0038] This utility model also provides a casting system for a rapid-cooling silicon ingot mold, which is a casting system designed for the aforementioned rapid-cooling silicon ingot mold and is used to complete the casting of the rapid-cooling silicon ingot mold.

[0039] This rapid-cooling silicon ingot mold uses an inverted bottom-pouring method for casting. (See below) Figure 4 , Figure 5 , Figure 6 The gating system includes a sprue 201, a runner 202, ceramic tubes 203, an ingate 204, and a riser 205. The sprue 201 is vertically arranged and is located near the side of one of the ingot mold bodies 101 where the width and height are located. The bottom of the sprue 201 is connected to the middle of the runner 202. The side of the runner 202 is connected to the first end of several ceramic tubes 203 along its length. The side of the ceramic tubes 203 is connected to the first end of several ingates 204. The second end of the ingates 204 is connected to the ingot mold body 101.

[0040] like Figure 6 As shown, a number of vertical risers 205 are evenly arranged at the top of the ingot mold body 101. Each riser 205 is connected to the ingot mold body 101, and the number of risers 205 is preferably 12.

[0041] The evenly distributed risers 205 facilitate the filling and shrinkage of the ingot mold 101 during the cooling process, avoiding casting defects such as shrinkage cavities and affecting product quality.

[0042] The ceramic tubes 203 are preferably eight in number, and the number of inlet runners 204 on each ceramic tube 203 is preferably two.

[0043] The inner diameter of the ceramic tube 203 is equal to the diameter of the inlet 204.

[0044] The ratio of the cross-sectional areas of the sprue 201, the runner 202, and the ceramic tube 203 is 105-121:95-105:12-13, and the ratio of the diameter of the sprue 201 to the height of the mold body 101 is 4:15.

[0045] To ensure the smoothness and continuity of the inner wall of the mold cavity 102, an inverted pouring method is adopted to improve the quality of the inner wall of the mold cavity 102. In addition, the second end of the ingate 204 is connected to the outermost edge of the ingot mold body 101, but not to the inner wall of the mold cavity 102, so that the smoothness of the inner wall of the mold cavity 102 will not be affected when the casting is removed after casting.

[0046] The above-mentioned gating system also includes several hangers 206. The hangers 206 are E-shaped. One side of the hangers 206 is used to clamp the straight section of the cooling pipe 106, and the other side of the hangers 206 is fixed to the upper mold.

[0047] The number of hangers 206 installed on the straight segment of each cooling pipe 106 is equal, and they are evenly distributed along the length of the straight segment of the hanger 206.

[0048] The evenly distributed hangers 206 are used to maintain the position of the cooling pipe 106 in the entire cavity. The clamping action of the hangers 206 prevents the cooling pipe 106 from moving during the pouring process.

[0049] The hanger 206 is made of 20# steel. After casting, it becomes an integral part of the ingot mold 101, and the excess part is removed through subsequent processing.

[0050] Before casting, the surface of the cooling pipe 106 needs to be treated. First, the surface is cleaned, and then an Al2O3 coating with a thickness of ≥200μm is thermally sprayed onto the surface of the cooling pipe 106. This process uses the heat resistance and heat insulation effect of the Al2O3 coating to avoid damage to the cooling pipe 106 during casting, thereby affecting the cooling effect of the mold.

[0051] The embodiments described above are not exhaustive, nor do they limit the scope of the present invention to the specific embodiments described herein. Clearly, many modifications and variations can be made based on the above description. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to effectively utilize the present invention and its modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rapid-cooling silicon ingot mold, characterized in that, include: The ingot mold body (101) has a rectangular parallelepiped structure and a mold cavity (102) is formed on one side surface of the ingot mold body (101). The mold cavity (102) is located on the surface where the length and width of the ingot mold body (101) are located, and the outline of the mold cavity (102) is an inverted square platform with rounded edges. The ingot mold body (101) is provided with a cooling pipe (106) in an S-shaped trajectory inside. The two ports of the cooling pipe (106) are located on the same side of the ingot mold body (101) where the length and height are located. The cooling pipe (106) is used to introduce a cooling medium to achieve silicon ingot cooling. The sides of the mold body (101) where the length and height are located are provided with several lifting shafts (105) for hoisting and transfer, and the two lifting shafts (105) are symmetrical about the center of the mold body (101).

2. The rapid-cooling silicon ingot mold according to claim 1, characterized in that, The ratio of the length, width and height of the ingot mold body (101) is 45-55:41-51:8-10, and the ratio of the depth of the mold cavity (102) to the height of the ingot mold body (101) is 1:

3. The bottom side of the mold cavity (102) is provided with a first rounded corner (103) and the top side is provided with a second rounded corner (104). The first rounded corner (103) and the second rounded corner (104) are tangent, and the radius of the first rounded corner (103) is twice the radius of the second rounded corner (104).

3. The rapid-cooling silicon ingot mold according to claim 1, characterized in that, The cooling pipe (106) includes an arc segment and a straight segment. The arc segment is a semi-circular trajectory. The trajectory of the cooling pipe (106) is located in the same horizontal plane. This horizontal plane is parallel to the bottom surface of the ingot mold body (101), and this horizontal plane is the symmetrical plane between the bottom surface of the ingot mold body (101) and the bottom surface of the mold cavity (102). The cooling pipe (106) is a high-strength seamless steel pipe with an outer diameter to height ratio of 1:7.5 to 8.5, a wall thickness of 5 to 7 mm, and an arc segment trajectory diameter to length ratio of 3:23 to 27.

4. The rapid-cooling silicon ingot mold according to claim 1, characterized in that, The surface of the cooling pipe (106) is thermally sprayed with an Al2O3 coating with a thickness of ≥200μm.

5. The rapid-cooling silicon ingot mold according to claim 1, characterized in that, The longitudinal edges of the ingot mold body (101) are rounded.

6. A casting system for a rapid-cooling silicon ingot mold, used for casting the rapid-cooling silicon ingot mold according to any one of claims 1-5, characterized in that, It includes a sprue (201), a gating system (202), several ceramic tubes (203), several ingates (204), and several risers (205), and is poured using an inverted bottom pouring method; The sprue (201) is vertically arranged and close to the side where the width and height of the ingot mold body (101) are located. The bottom of the sprue (201) is connected to the middle of the horizontal sprue (202). The side of the horizontal sprue (202) is connected to the first end of several ceramic tubes (203) along its length direction. The side of the ceramic tubes (203) is connected to the first end of several ingates (204). The second end of the ingates (204) is connected to the ingot mold body (101). The riser (205) is vertically located at the top of the ingot mold body (101) and connected to the ingot mold body (101), and is used for filling and shrinking during the silicon ingot cooling process.

7. The casting system for a rapid-cooling silicon ingot mold according to claim 6, characterized in that, The ratio of the cross-sectional areas of the sprue (201), the runner (202), and the ceramic tube (203) is 105-121:95-105:12-13. The ratio of the diameter of the sprue (201) to the height of the ingot mold body (101) is 4:

15. The inner diameter of the ceramic tube (203) is equal to the diameter of the inlet runner (204).

8. The casting system for a rapid-cooling silicon ingot mold according to claim 6, characterized in that, The number of ceramic tubes (203) is 8, and the number of inner gating channels (204) connected to each ceramic tube (203) is 2; The number of risers (205) is 12, and the risers (205) are evenly distributed on the upper end of the mold body (101).

9. The casting system for a rapid-cooling silicon ingot mold according to claim 6, characterized in that, It also includes several E-shaped hangers (206), one side of which is used to clamp the straight section of the cooling pipe (106), and the other side is fixed to the upper mold; The number of hangers (206) provided on the straight segment of each cooling pipe (106) is equal, and the hangers (206) are evenly distributed along the length of the straight segment of the cooling pipe (106).

10. The casting system for a rapid-cooling silicon ingot mold according to claim 9, characterized in that, The second end of the ingate (204) is not connected to the inner wall of the mold cavity (102).

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