Silicon rod manufacturing method, silicon rod, and photovoltaic silicon wafer

Abstract

A silicon rod manufacturing method, comprising: S1, cutting a round rod (100) in a first direction to obtain a first rough square rod (1) and a plurality of offcut blocks (2), the first direction being the axial direction of the round rod (100); S2, cutting each of the offcut blocks (2) in the first direction to obtain second rough square rods (21); S3, grinding the second rough square rods (21), and bonding and stacking the plurality of ground second rough square rods (21) in a second direction to obtain a second square rod (3), the second direction being orthogonal to the first direction; and S4, cutting the second square rod (3) in the second direction to obtain a plurality of second silicon rods (31). The method saves raw materials, and increases the utilization rate of the round rod (100), thereby improving the production efficiency of finished square rods, and reducing the production cost. The present invention also relates to a silicon rod and a photovoltaic silicon wafer.

Description

Silicon rod preparation method, silicon rod and photovoltaic silicon wafer

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202410241028.8, filed with the State Intellectual Property Office of China on March 4, 2024, entitled “Method for Preparing Silicon Rods,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the technical field of silicon rods, and in particular to a method for preparing a silicon rod, a silicon rod, and a photovoltaic silicon wafer. Background Art

[0004] In the prior art, the round rods used in silicon rod production are squared and the edges are removed. The edges are then directly recycled as crushed, pickled, and returned to the furnace. The edges cannot be used in production, resulting in low utilization of the raw materials for the round rods, loss of raw materials for the round rods, waste of processing costs, and increased costs for producing silicon rods.

[0005] Public content

[0006] The present disclosure aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present disclosure is to provide a method for preparing silicon rods that saves raw materials, improves the utilization rate of round rods, and thereby improves the production efficiency of finished square rods and reduces production costs.

[0007] The method for preparing a silicon rod according to an embodiment of the present disclosure includes:

[0008] S1. Cutting a round rod along a first direction to obtain a first blank square rod and a plurality of edge pieces, wherein the first direction is the axial direction of the round rod;

[0009] S2, cutting each of the edge pieces along the first direction to obtain a second blank square bar;

[0010] S3, grinding the second blank square rod, and bonding and stacking a plurality of ground second blank square rods along a second direction to obtain a second square rod, wherein the second direction is orthogonal to the first direction;

[0011] S4. Cutting the second square rod along the second direction to obtain a plurality of second silicon rods.

[0012] The silicon rod production method according to the disclosed embodiment cuts the edge material blocks into second blank square rods and processes the second blank square rods into second square rods. Compared with conventional silicon rod production methods, this method saves raw materials, improves the utilization rate of round rods, and thus improves the production efficiency of finished square rods and reduces production costs.

[0013] According to some embodiments of the present disclosure, in step S2, the length of the second blank square bar in the first direction is L1, the width of the second blank square bar in the third direction is W1, and the thickness of the second blank square bar in the second direction is D1. The third direction, the second direction and the first direction are orthogonal to each other, wherein L1, W1 and D1 respectively satisfy: 182mm≤L1≤900mm, 90mm≤W1≤108mm, and 20mm≤D1≤60mm.

[0014] According to some embodiments of the present disclosure, the plane range difference between the second blank square rod before grinding and the second blank square rod after grinding is ɑ, and the thickness of the second blank square rod after grinding in the second direction is D2, wherein ɑ and D2 respectively satisfy: ɑ≤0.3mm, 20mm≤D2≤60mm.

[0015] According to some embodiments of the present disclosure, the minimum distance between two adjacent second blank square bars of the second square bar is H, wherein H satisfies: H≤0.5 mm.

[0016] According to some embodiments of the present disclosure, the length of the second square rod in the first direction is L2, the width of the second square rod in the third direction is W2, and the thickness of the second square rod in the second direction is D3, wherein L2, W2 and D3 respectively satisfy: 182mm≤L2≤212mm, 90mm≤W2≤108mm, 300mm≤D3≤450mm.

[0017] According to some embodiments of the present disclosure, after step S3 and before step S4, the preparation method further includes:

[0018] S3′, curing the second square rod, wherein the curing time of the second square rod is greater than 1 hour.

[0019] According to some embodiments of the present disclosure, after step S1, the preparation method further includes:

[0020] S11, compacting the first blank square rod and cutting the first blank square rod along the first direction to obtain a plurality of first sub-rods;

[0021] S12, compacting the plurality of first sub-rods arranged along the second direction, and cutting the plurality of first sub-rods along the second direction to obtain a plurality of half-rods;

[0022] S13, after the plurality of half rods are bonded and stacked along the second direction, the plurality of half rods are polished as a whole to obtain a first silicon rod.

[0023] According to some embodiments of the present disclosure, a length of the first sub-rod in the first direction is L3, a width of the first sub-rod in the third direction is W3, and a thickness of the first sub-rod in the second direction is D4. The third direction, the second direction, and the first direction are orthogonal to each other, wherein L3, W3, and D4 respectively satisfy: 300 mm ≤ L3 ≤ 900 mm, 182 mm ≤ W3 ≤ 212 mm, and 90 mm ≤ D4 ≤ 108 mm.

[0024] According to some embodiments of the present disclosure, the length of the half rod in the first direction is L4, the width of the half rod in the third direction is W4, and the thickness of the half rod in the second direction is D5, wherein L4, W4 and D5 respectively satisfy: 182mm≤L4≤212mm, 182mm≤W4≤212mm, 90mm≤D5≤108mm.

[0025] According to some embodiments of the present disclosure, the length of the first silicon rod in the first direction is L5, the width of the first silicon rod in the third direction is W5, and the thickness of the first silicon rod in the second direction is D6, wherein L5, W5 and D6 respectively satisfy: 360mm≤L5≤840mm, 182mm≤W5≤212mm, and 182mm≤D6≤212mm.

[0026] Another object of the present disclosure is to provide a silicon rod formed using the silicon rod preparation method.

[0027] Another object of the present disclosure is to provide a photovoltaic silicon wafer formed by cutting the silicon rod along a cutting plane.

[0028] Additional aspects and advantages of the present disclosure will be given in part in the description that follows and, in part, will be obvious from the description that follows, or will be learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present disclosure will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0030] FIG1 is a flow chart of a method for preparing a silicon rod according to an embodiment of the present disclosure;

[0031] FIG2 is a flow chart of a method for preparing a first silicon rod according to an embodiment of the present disclosure;

[0032] FIG3 is a schematic diagram of a round rod according to an embodiment of the present disclosure;

[0033] FIG4 is a schematic diagram of an edge material block according to an embodiment of the present disclosure;

[0034] FIG5 is a schematic diagram of a second blank square rod according to an embodiment of the present disclosure;

[0035] FIG6 is a schematic diagram of cutting a second square blank rod to form a second silicon rod according to an embodiment of the present disclosure;

[0036] FIG7 is a schematic diagram of cutting a first blank square rod to form a first sub-rod according to an embodiment of the present disclosure;

[0037] FIG8 is a schematic diagram of cutting a first sub-rod into half-rods according to an embodiment of the present disclosure;

[0038] FIG. 9 is a schematic diagram of a half-rod according to an embodiment of the present disclosure.

[0039] Figure numerals: 100, round rod; 1, first blank square rod; 11, first sub-rod; 111, half rod; 2, edge block; 21, second blank square rod; 3, second square rod; 31, second silicon rod; 4, first silicon rod; 5, cutting net; 51, cutting wheel; 6, pressing device; 7, side head clamp. DETAILED DESCRIPTION

[0040] The following describes a method for preparing a silicon rod according to an embodiment of the present disclosure with reference to FIG1 to FIG9 .

[0041] As shown in FIG1 to FIG9 , the method for preparing a silicon rod according to an embodiment of the present disclosure includes:

[0042] S1. Cutting a round rod 100 along a first direction to obtain a first blank square rod 1 and a plurality of edge pieces 2. In the present disclosure, "plurality" means two or more. The first direction is the axial direction of the round rod 100 and is also the growth direction of the round rod 100.

[0043] For example, in the example of FIG3 , the length direction of the round rod 100 (for example, the up-down direction in FIG1 ) is the first direction. The round rod 100 is cut along the first direction using the cutting net 5, and the plurality of edge blocks 2 are the parts around the round rod 100, and the first blank square rod 1 is the part in the middle of the round rod 100. There are four edge blocks 2, and in the thickness direction of the edge blocks 2 (for example, the front-back direction in FIG4 ), one of the faces of the edge blocks 2 is an arc face, and the other face of the edge blocks 2 is a plane. The shape of the first blank square rod 1 is a quadrangular prism. The cutting net 5 can be composed of a long diamond wire or a ring-shaped diamond wire.

[0044] S2. Cut each scrap piece 2 along the first direction to obtain a second blank square rod 21. Referring to Figure 4 , the scrap piece 2 is cut using a cutting net 5. The cutting net 5 is operated at the set process line speed, feed rate, and position, cutting from the top of the scrap piece 2 until the scrap piece 2 is cut through and passes through the tail of the scrap piece 2. The second blank square rod 21 is in the shape of a quadrangular prism. By cutting multiple scrap pieces, multiple second blank square rods 21 can be obtained.

[0045] S3. Grind the second square rod 21 and glue together and stack the ground second square rods 21 along a second direction perpendicular to the first direction to form a second square rod 3. As shown in Figures 5 and 6, the second direction is the thickness direction of the second square rod 21 (e.g., the vertical direction in Figure 5). Use a trimmer to grind the cut surfaces of the second square rod 21 to make them smooth. After the cut surfaces of the second square rods 21 are smoothed, glue together the second square rods 21 along their thickness. After cleaning and air-drying the second square rods 21 in a cleaning machine, glue them together using a special glue to form the second square rod 3. The number of glued second square rods 21 can be 9-12, so that the resulting second square rod 3 meets the requirements of subsequent processing.

[0046] S4. Cut the second square rod 3 along the second direction to obtain a plurality of second silicon rods 31. Referring to FIG6 , the cutting mesh 5 cuts along the thickness direction of the second square rod 3. Subsequently, the cut second silicon rods 31 are grasped by the truss robot and placed in the grinder for polishing to facilitate subsequent use of the plurality of second silicon rods 31.

[0047] As a result, the material of the round rod 100 can be fully utilized, thereby improving the utilization rate of the round rod 100 , and the utilization rate of the round rod 100 is increased by 3.16%, further improving the production efficiency of the silicon rod.

[0048] According to the silicon rod production method of the embodiment of the present disclosure, the edge material block 2 is cut into the second blank square rod 21, and the second blank square rod 21 is processed into the second square rod 3. As compared with the traditional silicon rod production method, this method saves raw materials, improves the utilization rate of the round rod 100, and thus improves the production efficiency of the finished square rod and reduces the production cost.

[0049] According to some embodiments of the present disclosure, in step S2, the length of the second blank square rod 21 in the first direction is L1, the width of the second blank square rod 21 in the third direction is W1, and the thickness of the second blank square rod 21 in the second direction is D1. The third direction, the second direction and the first direction are orthogonal to each other, wherein L1, W1 and D1 respectively satisfy: 182mm≤L1≤900mm, 90mm≤W1≤108mm, and 20mm≤D1≤60mm.

[0050] Referring to Figures 4 and 5 , when the length of the second square rod 21 is less than 182 mm, the length of the second square rod 21 is too short, making it impossible to control the length of the second square rod 21 when cutting the scrap block 2, hindering smooth production. When the length of the second square rod 21 is greater than 900 mm, the length of the second square rod 21 is too long, and the length of the scrap block 2 cannot meet the length of the second square rod 21. When the width of the second square rod 21 is less than 90 mm, the width of the second square rod 21 is too small, making it impossible to fully utilize the scrap block 2, resulting in a waste of material. When the width of the second square rod 21 is greater than 108 mm, the shape of the second square rod 21 formed by cutting cannot be a regular quadrangular prism, hindering subsequent processing of the second square rod 21. When the thickness of the second square rod 21 is less than 20 mm, the thickness of the second square rod 21 is too thin, making it impossible to fully utilize the scrap block 2, resulting in a waste of material. When the thickness of the second blank square rod 21 is greater than 60 mm, the thickness of the edge material cannot meet the thickness of the second blank square rod 21, and the cut second blank square rod 21 cannot become a regular quadrangular prism, which is not conducive to subsequent processing of the second blank square rod 21.

[0051] As a result, the length, width and thickness of the second blank square rod 21 respectively meet the following requirements: 182mm≤L1≤900mm, 90mm≤W1≤108mm, and 20mm≤D1≤60mm. This allows the second blank square rod 21 to fully utilize the material of the edge material, avoiding waste of the edge material, and also allows the second blank square rod 21 to form a quadrangular prism, which is beneficial to the subsequent processing of the second blank square rod 21.

[0052] According to some embodiments of the present disclosure, the planar range of the second square bar 21 before grinding and the second square bar 21 after grinding is ɑ, and the thickness of the second square bar 21 in the second direction after grinding is D2, where ɑ and D2 respectively satisfy: ɑ ≤ 0.3 mm, 20 mm ≤ D2 ≤ 60 mm. As shown in Figure 6, the planar range is the difference between the highest point and the lowest point of the plane, that is, the difference between the thickness of the second square bar 21 after grinding and the thickness of the second square bar 21 before grinding is ɑ, and ɑ satisfies: ɑ ≤ 0.3 mm. When ɑ > 0.3 mm, the planar range of the second square bar 21 is large, and the material loss caused by grinding the second square bar 21 is large. When the planar range of the second square bar 21 is ɑ ≤ 0.3 mm, the loss of the second square bar 21 can be reduced, which is beneficial for the further processing and use of the second square bar 21.

[0053] When the thickness of the second square rod 21 after grinding is less than 20 mm, the second square rod 21 is relatively thin, and the grinding process causes significant wear and tear on the second square rod 21. When the thickness of the second square rod 21 after grinding is greater than 60 mm, the second square rod 21 is too thick, making it difficult to achieve a smooth cut surface, which is detrimental to the bonding of multiple second square rods 21. Therefore, when the thickness of the second square rod 21 satisfies 20 mm ≤ D2 ≤ 60 mm, wear and tear on the second square rod 21 during grinding can be reduced, and the smooth cut surface of the second square rod 21 can be facilitated for subsequent processing.

[0054] According to some embodiments of the present disclosure, the minimum distance between two adjacent second blank square bars 21 of the second square bar 3 is H, where H satisfies: H ≤ 0.5 mm. For example, in the example of FIG6 , when the minimum distance between two adjacent second blank square bars 21 is greater than 0.5 mm, the minimum distance between the two adjacent second blank square bars 21 is too large, resulting in a large gap when bonding the second blank square bars 21. This is not conducive to maintaining good adhesion between the two adjacent second blank square bars 21 and is not conducive to the use of the second square bar 3. Therefore, by ensuring that the minimum distance between two adjacent second blank square bars 21 satisfies H ≤ 0.5 mm, the adhesion between the adjacent second blank square bars 21 is strong when multiple second blank square bars 21 are bonded together, which facilitates the further processing and use of the second square bar 3.

[0055] According to some embodiments of the present disclosure, the length of the second square rod 3 in the first direction is L2, the width of the second square rod 3 in the third direction is W2, and the thickness of the second square rod 3 in the second direction is D3, where L2, W2, and D3 respectively satisfy the following conditions: 300 mm ≤ L2 ≤ 450 mm, 90 mm ≤ W2 ≤ 108 mm, and 182 mm ≤ D3 ≤ 212 mm. Referring to FIG6 , when the length of the second square rod 3 is less than 300 mm, the length of the second square rod 3 is relatively short. When bonding multiple second square rod blanks 21, the length of the second square rod 21 is greater than the length of the second square rod 3, and the length of the second square rod 21 cannot meet the required length of the second square rod 3. When the length of the second square rod 3 is greater than 450 mm, the length of the second square rod 3 is too long, the length of the second square rod 21 is fixed, and multiple second square rod blanks 21 cannot be bonded together in the length direction, thus failing to achieve the required length of the second square rod 3. When the width of the second square rod 3 is less than 90 mm, the width of the second square rod 3 is too small, and the width of the second square rod blank 21 will be larger than the width of the second square rod 3, making it impossible to achieve the desired width of the second square rod 3 during bonding. When the width of the second square rod 3 is greater than 108 mm, the width of the second square rod 3 is too wide, and the width of the second square rod blank 21 is smaller than the width of the second square rod 3, making it impossible to achieve the desired width of the second square rod 3 during bonding. When the thickness of the second square rod 3 is less than 182 mm, the thickness of the second square rod 3 is too thin, and when bonding multiple second square rod blanks 21, the number of second square rod blanks 21 must be reduced. This arrangement cannot meet the needs of the second square rod 3 formed. When the thickness of the second square rod 3 is greater than 212 mm, the number of second square rod blanks 21 required for bonding is too large, and the number of second square rod blanks 21 may not meet the needs of the second square rod 3.

[0056] Therefore, the length, width and thickness of the second square rod 3 respectively meet the following requirements: 300 mm ≤ L2 ≤ 450 mm, 90 mm ≤ W2 ≤ 108 mm, and 182 mm ≤ D3 ≤ 212 mm. The second blank square rod 21 in step S3 can meet the size requirements of the second square rod 3, can be smoothly processed into the second square rod 3, and is conducive to subsequent processing of the second square rod 3.

[0057] According to some embodiments of the present disclosure, after step S3 and before step S4, the method further includes:

[0058] S3', curing the second square rods 3. The curing time of the second square rods 3 is longer than 1 hour. Referring to Figures 1 and 6, after the plurality of second square rod blanks 21 are bonded together, curing is performed to solidify the adhesive used during bonding, thereby strengthening the bonding between the plurality of second square rod blanks 21 and preventing the second square rods 3 from separating during subsequent production.

[0059] According to some embodiments of the present disclosure, after step S1, the method further includes:

[0060] S11, compacting the first blank square rod 1, and cutting the first blank square rod 1 along the first direction to obtain a plurality of first sub-rods 11. Referring to Figures 2 and 7, the first blank square rod 1 is compacted by the compacting device 6 according to the set torque to fix the first blank square rod 1 and ensure that the first blank square rod 1 does not move, so that the first blank square rod 1 can be cut. Subsequently, the cutting net 5 is used to cut into the top of the first blank square rod 1 until the cutting net 5 cuts through the first blank square rod 1 and passes through the tail of the first blank square rod 1. In this way, the first blank square rod 1 is divided into two first sub-rods 11. In addition, due to the concentric circles in the round rod 100, in the traditional silicon rod preparation method, the direction of cutting the round rod 100 is parallel to the concentric circles, which will retain the concentric circles. As a result, abnormal concentric circles may occur during the use of the silicon rod, resulting in damage to the silicon rod.

[0061] In the present application, by cutting the first blank square rod 1 along the first direction, the cutting path destroys the concentric circles of the first blank square rod 1, thereby avoiding the occurrence of concentric circle anomalies in subsequent silicon rods, thereby avoiding the loss of battery cells caused by concentric circle anomalies.

[0062] S12. Compress the multiple first sub-rods 11 arranged along the second direction and cut the multiple first sub-rods 11 along the second direction to obtain multiple half-rods 111. As shown in Figure 8, the first sub-rods 11 are horizontally compressed by side clamps 7 to secure the multiple first sub-rods 11 and prevent displacement. Side clamps 7 are located on both sides of the first sub-rods 11 in the width direction, with 28-36 side clamps 7 being present. Cutting wheels 51 are positioned around the multiple first sub-rods 11, and cutting nets 5 are suspended from the cutting wheels 51. Multiple cutting nets 5 are arranged at intervals along the first direction. The multiple cutting nets 5 cut the multiple first sub-rods 11 horizontally according to the set process line speed, feed speed, and position. Specifically, the cutting nets 5 pass through one end of the first sub-rod 11 in the second direction until they penetrate the first sub-rod 11, thereby obtaining multiple half-rods 111. Ultimately, approximately 6-10 half-rods 111 are obtained. This improves production efficiency and the final product quality rate.

[0063] S13. After the multiple half-rods 111 are bonded and stacked along the second direction, the multiple half-rods 111 are polished as a whole to obtain the first silicon ingot 4. For example, in the example of FIG9 , the multiple half-rods 111 are bonded and stacked, and the outer circumferences of the multiple half-rods 111 are polished to maintain a smooth and flat outer circumference, thereby enhancing the aesthetics of the first silicon ingot 4. The glue used for bonding is a special glue.

[0064] According to some embodiments of the present disclosure, the length of the first sub-rod 11 in the first direction is L3, the width of the first sub-rod 11 in the third direction is W3, and the thickness of the first sub-rod 11 in the second direction is D4. The third direction, the second direction, and the first direction are orthogonal to each other, wherein L3, W3, and D4 respectively satisfy: 300 mm ≤ L3 ≤ 900 mm, 182 mm ≤ W3 ≤ 212 mm, and 90 mm ≤ D4 ≤ 108 mm.

[0065] Referring to Figure 8 , when the length of the first sub-rod 11 is less than 300 mm, the length of the first sub-rod 11 is too short. When the first sub-rod 11 is cut, the length of the first blank square rod 1 is fixed, and the length of the first blank square rod 1 cannot meet the required length of the first sub-rod 11. When the length of the first sub-rod 11 is greater than 450 mm, the length of the first sub-rod 11 is too long, and the length of the first blank square rod 1 is less than the required length of the first sub-rod 11. The length of the first blank square rod 1 after cutting does not change, and thus the required length of the first sub-rod 11 cannot be met. When the width of the first sub-rod 11 is less than 182 mm, the width of the first sub-rod 11 is too small, and the width of the first blank square rod 1 is fixed. Cutting the edges of the first blank square rod 1 to shorten the width will result in material waste and increase the production process. When the width of the first sub-rod 11 is greater than 212 mm, the width of the first sub-rod 1 is too wide, and the width of the first blank square rod 1 is less than the width of the first sub-rod 11, and the required width of the first sub-rod 11 cannot be met. When the thickness of the first sub-rod 11 is less than 90 mm, the thickness of the first sub-rod 11 is too thin, and the material of the first blank square rod 1 cannot be fully utilized, resulting in material waste of the first blank square rod 1. When the thickness of the first sub-rod 11 is greater than 212 mm, the thickness of the first blank square rod 1 is less than the thickness of the first sub-rod 11, and the thickness of the multiple first sub-rods 11 cannot be met.

[0066] Therefore, the length, width and thickness of the first sub-rod 11 respectively satisfy the following conditions: 300 mm ≤ L3 ≤ 900 mm, 182 mm ≤ W3 ≤ 212 mm, and 90 mm ≤ D4 ≤ 108 mm. The first blank square rod 1 can be smoothly processed into the first sub-rod 11, thereby improving production efficiency and facilitating subsequent processing of the first sub-rod 11.

[0067] According to some embodiments of the present disclosure, the length of the half rod 111 in the first direction is L4, the width of the half rod 111 in the third direction is W4, and the thickness of the half rod 111 in the second direction is D5, wherein L4, W4 and D5 respectively satisfy: 182mm≤L4≤212mm, 182mm≤W4≤212mm, 90mm≤D5≤108mm.

[0068] Referring to Figure 8 , when the length of half-rod 111 is less than 182 mm, it is too short. When cutting the first sub-rod 11, the first sub-rod 11 can be cut to form more half-rods 111, but this is not conducive to the subsequent production, processing, and use of the half-rod 111. When the length of half-rod 111 is greater than 450 mm, it is too long, resulting in a smaller number of half-rods 111 after cutting the first sub-rod 11, which is not conducive to material utilization. When the width of half-rod 111 is less than 182 mm, the width of half-rod 111 is too small, and the width of the first sub-rod 11 is fixed. Cutting the edges of the first sub-rod 11 is necessary, resulting in material waste and increased production steps. When the width of half-rod 111 is greater than 212 mm, the width of half-rod 111 is too wide, and the first sub-rod 11 cannot meet the width requirements of multiple half-rods 111. When the thickness of the half-rod 111 is less than 90 mm, the thickness of the half-rod 111 is too thin, and the material of the first sub-rod 11 cannot be fully utilized, resulting in material waste of the first sub-rod 11. When the thickness of the half-rod 111 is greater than 212 mm, the first sub-rod 11 cannot meet the thickness requirements of multiple half-rods 111.

[0069] Therefore, the length, width and thickness of the half rod 111 respectively meet the following requirements: 300mm≤L4≤900mm, 182mm≤W4≤212mm, 90mm≤D5≤108mm. The first sub-rod 11 can be smoothly processed into the half rod 111, which improves production efficiency and facilitates subsequent processing of the half rod 111.

[0070] According to some embodiments of the present disclosure, the length of the first silicon rod 4 in the first direction is L5, the width of the first silicon rod 4 in the third direction is W5, and the thickness of the first silicon rod 4 in the second direction is D6, wherein L5, W5 and D6 respectively satisfy: 360mm≤L5≤840mm, 182mm≤W5≤212mm, and 182mm≤D6≤212mm.

[0071] Referring to Figure 9 , when the length of the first silicon rod 4 is less than 360 mm, the length of the first silicon rod 4 is too short, making it difficult to use. When the length of the first silicon rod 4 is greater than 450 mm, the length of the first silicon rod 4 is too long, requiring an increased number of bonded half-rods 111, increasing material consumption. When the width of the first silicon rod 4 is less than 90 mm, the width of the first silicon rod 4 is small, resulting in a smaller size of the first silicon rod 4 and a lack of width for the half-rods 111 to accommodate the width of the first silicon rod 4, making the size of the first silicon rod 4 difficult to use. When the width of the first silicon rod 4 is greater than 108 mm, the width of the first silicon rod 4 is too wide, and the bonded half-rods 111 also lack the width of the first silicon rod 4, resulting in a larger size of the first silicon rod 4 and making it difficult to use. When the thickness of the first silicon rod 4 is less than 182 mm, the thickness of the first silicon rod 4 is relatively thin, requiring fewer half-rods 111, resulting in wasted half-rods 111. When the thickness of the first silicon rod 4 is greater than 212 mm, the first silicon rod 4 requires a large number of half rods 111 , and the number of half rods 111 may not meet the usage requirements of the first silicon rod 4 .

[0072] Therefore, the length, width and thickness of the first silicon rod 4 respectively meet the following requirements: 300 mm ≤ L5 ≤ 450 mm, 90 mm ≤ W5 ≤ 108 mm, and 182 mm ≤ D6 ≤ 212 mm. A plurality of half rods 111 can be bonded together to form the first silicon rod 4. Furthermore, when packaging the first silicon rod 4, there is no need to develop new packaging materials, which can save the design and development cost of the packaging mold and is more convenient.

[0073] It should be noted that the cutting plane in the present disclosure refers to the plane along which the first silicon ingot 4 and the second silicon ingot 31 are ultimately cut into silicon wafers. This plane is parallel to the first and third directions. Therefore, the silicon wafers formed by cutting the first silicon ingot 4 and the second silicon ingot 31 are parallel in one direction to the growth direction of the round ingot 100, namely the first direction. Therefore, the photovoltaic silicon wafers cut from the first silicon ingot 4 and the second silicon ingot 21 will not have concentric circles, thus ensuring the quality of the photovoltaic silicon wafers.

[0074] Preferably, the present disclosure can process the entire round rod to obtain photovoltaic silicon wafers. For example, when the round rod is judged to have high oxygen content, that is, there is a concentric circle problem, it can be processed according to the present disclosure to obtain photovoltaic silicon wafers without the concentric circle problem; when the round rod is tested and judged to be qualified, that is, there is no concentric circle problem with high oxygen content, the round rod can be processed according to the present disclosure, or it can be processed according to a conventional cutting method to obtain photovoltaic silicon wafers without the concentric circle problem. Optionally, when the round rod is judged to have high oxygen content, that is, there is a concentric circle problem, the high-oxygen part of the round rod can be cut off and collected, and then the cut round rod can be processed according to the present disclosure, and then the low-oxygen round rod obtained after cutting in the original round rod can be processed according to a conventional cutting method to finally obtain photovoltaic silicon wafers without the concentric circle problem.

[0075] Other structures and operations of the method for preparing silicon rods according to the embodiment of the present disclosure are known to those skilled in the art and will not be described in detail here.

[0076] In the description of the present disclosure, it should be understood that the terms "center", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure.

[0077] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "example," "specific example," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0078] Although the embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for preparing a silicon rod, characterized in that: include: S1, cutting a round rod (100) along a first direction to obtain a first blank square rod (1) and a plurality of edge material blocks (2), wherein the first direction is the axial direction of the round rod (100); S2, cutting each of the edge material blocks (2) along the first direction to obtain a second blank square bar (21); S3, grinding the second blank square rod (21), and bonding and stacking a plurality of ground second blank square rods (21) along a second direction to obtain a second square rod (3), wherein the second direction is orthogonal to the first direction; as well as S4, cutting the second square rod (3) along the second direction to obtain a plurality of second silicon rods (31).

2. The method for preparing a silicon rod according to claim 1, wherein: In step S2, the length of the second blank square bar (21) in the first direction is L1, the width of the second blank square bar (21) in the third direction is W1, and the thickness of the second blank square bar (21) in the second direction is D1, and the third direction, the second direction and the first direction are orthogonal to each other, wherein L1, W1 and D1 respectively satisfy: 182mm≤L1≤900mm, 90mm≤W1≤108mm, and 20mm≤D1≤60mm.

3. The method for preparing a silicon rod according to claim 2, wherein: The plane range difference between the second blank square rod (21) before grinding and the second blank square rod (21) after grinding is ɑ, and the thickness of the second blank square rod (21) in the second direction after grinding is D2, wherein ɑ and D2 respectively satisfy: ɑ≤0.3mm, 20mm≤D2≤60mm.

4. The method for preparing a silicon rod according to any one of claims 1 to 3, characterized in that: The minimum distance between two adjacent second blank square bars (21) of the second square bar (3) is H, wherein H satisfies: H≤0.5mm.

5. The method for preparing a silicon rod according to any one of claims 1 to 4, characterized in that: The length of the second square rod (3) in the first direction is L2, the width of the second square rod (3) in the third direction is W2, and the thickness of the second square rod (3) in the second direction is D3, wherein L2, W2 and D3 respectively satisfy: 182mm≤L2≤212mm, 90mm≤W2≤108mm, 300mm≤D3≤450mm.

6. The method for preparing a silicon rod according to any one of claims 1 to 5, characterized in that: After step S3 and before step S4, the method further includes: S3', curing the second square rod (3), wherein the curing time of the second square rod is greater than 1 hour.

7. The method for preparing a silicon rod according to any one of claims 1 to 6, characterized in that: After step S1, the method further includes: S11, compacting the first blank square rod (1), and cutting the first blank square rod (1) along the first direction to obtain a plurality of first sub-rods (11); S12, compacting the plurality of first sub-rods (11) arranged along the second direction, and cutting the plurality of first sub-rods (11) along the second direction to obtain a plurality of half-rods (111); and S13, after the plurality of half rods (111) are bonded and stacked along the second direction, the plurality of half rods (111) are polished as a whole to obtain a first silicon rod (4).

8. The method for preparing silicon rods according to claim 7, wherein: The length of the first sub-rod (11) in the first direction is L3, the width of the first sub-rod (11) in the third direction is W3, and the thickness of the first sub-rod (11) in the second direction is D4. The third direction, the second direction and the first direction are orthogonal to each other, wherein L3, W3 and D4 respectively satisfy: 300mm≤L3≤900mm, 182mm≤W3≤212mm, and 90mm≤D4≤108mm.

9. The method for preparing a silicon rod according to claim 7 or 8, characterized in that: The length of the half rod (111) in the first direction is L4, the width of the half rod (111) in the third direction is W4, and the thickness of the half rod (111) in the second direction is D5, wherein L4, W4 and D5 respectively satisfy: 182mm≤L4≤212mm, 182mm≤W4≤212mm, 90mm≤D5≤108mm.

10. The method for preparing a silicon rod according to any one of claims 7 to 9, characterized in that: The length of the first silicon rod (4) in the first direction is L5, the width of the first silicon rod (4) in the third direction is W5, and the thickness of the first silicon rod (4) in the second direction is D6, wherein L5, W5 and D6 respectively satisfy: 360mm≤L5≤840mm, 182mm≤W5≤212mm, and 182mm≤D6≤212mm.

11. A silicon rod, characterized in that: The silicon rod is formed by the method for preparing the silicon rod according to any one of claims 1 to 10.

12. A photovoltaic silicon wafer, characterized in that: The silicon rod according to claim 11 is cut along a cutting plane.

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