Monocrystalline silicon wafer, monocrystalline silicon rod and preparation method, solar cell and module

Abstract

This invention provides a monocrystalline silicon wafer, comprising a wafer body, the wafer body including multiple straight-walled portions and multiple chamfered portions, the straight-walled portions and chamfered portions being alternately connected end-to-end, the chamfered portions being straight lines, and the straight line formed by connecting any end of a chamfered portion to the center point of the wafer body intersecting the line of the wafer body. <110> The angle between crystal orientations is not less than 0.35° and not greater than 3.2°. The beneficial effect of this invention is that the monocrystalline silicon wafer has a chamfered portion, and the chamfered portion is straight-line in shape, which avoids poor positioning of the monocrystalline silicon wafer during downstream battery electrode printing and battery module assembly, and avoids misalignment during monocrystalline silicon wafer splicing; at the same time, during the preparation of the monocrystalline silicon rod, a grinding method is adopted in which the monocrystalline silicon rod does not rotate but the grinding wheel rotates, resulting in good consistency of the grinding curvature of the edges of the monocrystalline silicon rod.

Description

Technical Field

[0001] This invention belongs to the field of silicon wafer manufacturing technology, and in particular relates to a monocrystalline silicon wafer, a monocrystalline silicon rod and its preparation method, as well as solar cells and modules. Background Technology

[0002] Currently, the four corners of silicon wafers used in solar energy are generally rounded, such as... Figure 1 As shown, this type of corner can effectively reduce stress concentration and reduce the breakage of silicon wafers during transportation and processing. However, as the size of silicon wafers increases, the requirements for dimensional accuracy and positioning in downstream battery manufacturing and module assembly become increasingly stringent. This arc-shaped structure can hardly meet the positioning requirements of downstream battery electrode printing and battery module assembly. In other words, the positioning effect of this arc-shaped structure is poor when positioning by arc corners. For example, when two single-crystal silicon wafers with arc-shaped structures on the same plane are spliced ​​together, they are prone to misalignment.

[0003] In addition, the following defects exist in the process of turning monocrystalline silicon rods into monocrystalline silicon wafers with arc-shaped structures: The existing polishing process is as follows: Figure 2 As shown, v1 is the silicon rod feed direction, v2 is the monocrystalline silicon rod rotation direction, and v3 is the grinding wheel rotation direction. During grinding, the monocrystalline silicon rod and the grinding wheel rotate simultaneously, making it difficult to control the consistency of the grinding radius of the four corners of the monocrystalline silicon rod. As the radius gradually decreases, due to the precision of the cutting tools, the angles of entry and exit are inconsistent, resulting in asymmetry of the radius. Generally, there is more wear at the entry point and less wear at the exit point, meaning some corners are over-ground and some corners are under-ground, thus affecting the yield of monocrystalline silicon wafers. Summary of the Invention

[0004] In view of the above problems, the present invention provides a monocrystalline silicon wafer, a monocrystalline silicon rod and a method for preparing it, a solar cell and a module, to solve the above or other problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a single-crystal silicon wafer, comprising a silicon wafer body, the silicon wafer body including multiple straight-walled portions and multiple chamfered portions, the straight-walled portions and the chamfered portions being connected end-to-end alternately, the chamfered portions being straight lines, and the straight line formed by connecting the endpoint of any end of the chamfered portion to the center point of the silicon wafer body intersecting the line of the silicon wafer body. <110> The angle between crystal orientations is not less than 0.35° and not greater than 3.2°.

[0006] Furthermore, the length of the chamfer is 1.5-10mm.

[0007] Furthermore, the crystal orientation along the thickness direction of the silicon wafer body is... <100> .

[0008] Furthermore, the angle between the straight line formed by connecting the endpoint of any end of the chamfer to the center point of the silicon wafer body and the crystal orientation of the silicon wafer body is 0.39°.

[0009] Furthermore, there are four straight-walled sections and four chamfered sections.

[0010] A single-crystal silicon rod includes a silicon rod body, which is wire-cut to form multiple single-crystal silicon wafers as described above.

[0011] Furthermore, the silicon rod body includes multiple first straight wall portions and multiple first chamfered portions, which are connected end-to-end alternately. The first chamfered portions are straight, and the line connecting any end of the first chamfered portion to the center point of the cross-section of the silicon rod body is perpendicular to the silicon rod body. <110> The angle between crystal orientations is not less than 0.35° and not greater than 3.2°.

[0012] Furthermore, the length of the first chamfer is 1.5-10mm.

[0013] Furthermore, the axial crystal orientation index of the silicon rod body is <100> .

[0014] A method for preparing a single-crystal silicon rod, characterized by comprising the following steps:

[0015] The single crystal wafer is cut into square shapes to form multiple straight-walled sections and multiple edges;

[0016] The edges of the squared single crystal wafer are chamfered, and the chamfer is a right angle.

[0017] Furthermore, when chamfering the edges, a grinding wheel is used to polish the edges. During the polishing process, the grinding wheel rotates, and the squared single crystal rod is fed by translation without rotating.

[0018] A solar cell comprising the aforementioned monocrystalline silicon wafer.

[0019] A solar cell module comprising the aforementioned solar cell.

[0020] A solar cell strip, made by cutting the aforementioned solar cells.

[0021] A shingled battery module includes multiple shingled battery strings, each shingled battery string comprising multiple solar cell strips as described above.

[0022] By adopting the above technical solution, the single crystal rods of Czochralski-grown single crystals are squared and chamfered to prepare single crystal silicon rods, and then the single crystal silicon rods are wire-cut to prepare single crystal silicon wafers. When chamfering the single crystal silicon rods, a grinding wheel is used to grind the edges of the squared single crystal silicon rods to form chamfered parts. During the grinding process, the single crystal silicon rod itself does not rotate, but only performs axial feeding. The grinding wheel rotates to grind the edges of the single crystal silicon rods, which makes the grinding curvature of the single crystal silicon rods very consistent and controllable, avoiding any impact on the quality of the single crystal silicon wafers and improving the yield of single crystal silicon wafers.

[0023] Because the above-mentioned method of polishing the edges of the monocrystalline silicon rod is used, the monocrystalline silicon rod has a first chamfer, and the first chamfer is straight, which makes it easy to control the shape of the chamfer of the monocrystalline silicon wafer after the monocrystalline silicon rod is cut.

[0024] The wire-cut monocrystalline silicon wafers have chamfered edges, and the chamfered edges are straight lines. This facilitates the positioning of the monocrystalline silicon wafers during downstream battery electrode printing and battery module assembly, resulting in good positioning performance and preventing misalignment during wafer splicing. Furthermore, the straight line formed by connecting any endpoint of the chamfered edge to the center point of the monocrystalline silicon wafer... <110> The angle between crystal orientations is limited to reduce the breakage rate of monocrystalline silicon wafers. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a silicon wafer in the prior art;

[0026] Figure 2 This is a schematic diagram of the polishing process of a single-crystal silicon rod in the existing technology;

[0027] Figure 3 These are schematic diagrams of single-crystal silicon wafer structures according to some embodiments of the present invention;

[0028] Figure 4 These are schematic diagrams illustrating the polishing process of single-crystal silicon rods according to some embodiments of the present invention;

[0029] Figure 5 This is a schematic diagram of the crystal orientation of a single-crystal silicon wafer according to some embodiments of the present invention.

[0030] In the picture:

[0031] 1. Straight wall section 2. Chamfered section G. Diagonal

[0032] A. Center angle v1, silicon rod feed direction v2, single crystal silicon rod rotation direction

[0033] v3. Grinding wheel rotation direction Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0035] Figure 3 A schematic diagram of an embodiment of the present invention is shown, specifically illustrating the structure of this embodiment. This embodiment relates to a monocrystalline silicon wafer, a monocrystalline silicon rod and its preparation method, a solar cell and a module. The monocrystalline silicon rod is squared and chamfered from a Czochralski-grown monocrystalline silicon rod to prepare a monocrystalline silicon rod, and then wire-cut to prepare a monocrystalline silicon wafer. During chamfering, the monocrystalline silicon rod is chamfered at a right angle, giving the monocrystalline silicon wafer a chamfered portion with a straight line shape. This avoids poor positioning of the monocrystalline silicon wafer during downstream battery electrode printing and battery module assembly, and prevents misalignment during splicing. Simultaneously, during chamfering, a grinding wheel is used to polish the monocrystalline silicon rod. The monocrystalline silicon rod itself does not rotate, avoiding the problem of inconsistent grinding radius of the monocrystalline silicon rod's edges, thus preventing any impact on the quality of the monocrystalline silicon wafer and improving the yield of the monocrystalline silicon wafer.

[0036] A type of single-crystal silicon wafer, such as Figure 3 and Figure 5 As shown, the device includes a silicon wafer body, which comprises multiple straight-walled portions 1 and multiple chamfered portions 2. The straight-walled portions 1 and chamfered portions 2 are connected end-to-end alternately. The chamfered portions 2 are straight lines. In other words, the silicon wafer body comprises multiple straight-walled portions 1 and multiple chamfered portions 2, which are connected end-to-end alternately to form the shape of the silicon wafer body. The number of straight-walled portions 1 is the same as the number of chamfered portions 2. Each straight-walled portion 1 is connected to both ends with a chamfered portion 2. The number of straight-walled portions 1 can be four, five, six, or other numbers, depending on the actual needs; no specific requirements are specified here.

[0037] The chamfered portion 2 is straight, meaning it is a straight line, not an arc. The length of the chamfered portion 2 is 1.5-10mm, selected according to actual needs; no specific requirements are specified here. The straight wall portion 1 is also straight. The straight chamfered portion 2 facilitates the positioning of the monocrystalline silicon wafer during cell fabrication and module assembly, providing good positioning, reducing misalignment, and ensuring the quality of the manufactured cells and modules.

[0038] A straight line formed by connecting the endpoint of any end of the chamfered portion 2 of the silicon wafer body to the center point of the silicon wafer body is perpendicular to the silicon wafer body. <110> The angle between crystal orientations is not less than 0.35° and not greater than 3.2°, and the length of the chamfered portion 2 is 1.5-10mm. A straight line connecting any end of the chamfered portion 2 of the silicon wafer body to the center point of the silicon wafer body is defined as intersecting the silicon wafer body's... <110> If the angle between crystal orientations is θ, then 0.35°≤θ≤3.2°.

[0039] In monocrystalline silicon <110> Crystal orientation is the direction of easy cleavage, such as Figure 5 As shown, due to the stress concentration problem at the angle between the straight wall portion 1 and the chamfer, if the silicon wafer is not chamfered, the direction of the angle formed by two adjacent straight wall portions 1 is exactly the same as the angle between the straight wall portion 1 and the chamfer. <110> Overlapping, becoming the easiest direction for cleavage, will cause a large amount of edge chipping and fragmentation of the silicon wafer during later turnover and processing. Therefore, chamfering is used in actual manufacturing. Since the fragmentation rate caused by edge chipping at the four corners of the silicon wafer is related to the length of the chamfer, when the diameter and side length of the silicon wafer are constant, the chamfer length is directly related to the θ angle. Studies have found that as the θ angle increases, that is, the further the deviation... <110> With increasing crystal orientation, the silicon wafer fragmentation rate gradually decreases. When θ > 0.35°, the fragmentation rate reaches a stable value. However, when θ further increases to 3.2°, the fragmentation rate begins to rise again. This is because as θ increases, the chamfer length increases, leading to a higher probability of contact with other objects and thus a higher fragmentation rate. Therefore, the angle θ is limited; preferably, 0.35° ≤ θ ≤ 3.2°, to reduce the fragmentation rate of the silicon wafer. The length of the chamfer is calculated based on θ and the side length and diameter of the silicon wafer body.

[0040] The following explanation uses an example where there are four straight-walled sections 1. When there are four straight-walled sections 1, there are also four chamfered sections 2. The straight-walled sections 1 and chamfered sections 2 are connected alternately, end to end, forming the shape of a single-crystal silicon wafer. This single-crystal silicon wafer is quadrilateral, with its four vertices chamfered at right angles, resulting in a straight-line shape. This single-crystal silicon wafer… <110> The crystal orientation coincides with the diagonal G of the silicon wafer body.

[0041] The two ends of the chamfered portion 2 are respectively aligned with the center point of the silicon wafer body, and the included angle between the two lines is the central angle A. When the midline of the central angle A coincides with the diagonal G of the silicon wafer body, that is, when the midline of the central angle A coincides with the diagonal G of the silicon wafer body... <110> If the crystal orientations coincide, then let half of the central angle A be the same as θ. The angle θ is not less than 0.35° and not greater than 3.2°. Therefore, the angle A corresponding to the center of the chamfered portion 2 and the center of the silicon wafer body is not less than 0.7° and not greater than 6.4°. In other words, the angle A is not less than 0.7° and not greater than 6.4°. That is, one end of the chamfered portion 2 forms a straight line with the center point of the silicon wafer body. The angle between this straight line and the diagonal G of the silicon wafer body is θ. This angle θ is greater than 0.35° and less than 3.2°. The closer the straight line formed by the chamfered portion 2 and the center point of the silicon wafer body is to the diagonal G, the smaller the angle θ. The farther the straight line formed by the chamfered portion 2 and the center point of the silicon wafer body is from the diagonal G, the larger the angle θ.

[0042] When the median of central angle A does not coincide with the diagonal G of the silicon wafer body, that is, when the median of central angle A does not coincide with the diagonal G of the silicon wafer body... <110> The crystal orientations do not coincide, and either end of the chamfered portion 2 is aligned with the center point of the silicon wafer body in a straight line. <110> The angle between the crystal orientations is θ, where 0.35° ≤ θ ≤ 3.2°. At this point, the other end of the chamfered portion 2 is aligned with the center point of the silicon wafer body, forming a straight line with the silicon wafer body. <110> The angle between crystal orientations is not the same as θ.

[0043] The side length, number of sides, and thickness of the silicon wafer are selected according to actual needs, and no specific requirements are specified here.

[0044] The crystal orientation along the thickness direction of the silicon wafer is: <100> .

[0045] A single-crystal silicon rod includes a silicon rod body, which is wire-cut into multiple single-crystal silicon wafers as described above. The silicon rod body has a rod structure with a certain length, and its cross-sectional shape is adapted to the shape of the single-crystal silicon wafers. The silicon rod body includes multiple first straight wall portions and multiple first chamfered portions, which are alternately connected end-to-end to form the structure of the silicon rod body. The number of first straight wall portions matches the number of first chamfered portions. Each first straight wall portion has a first chamfered portion connected to both ends. The number of first straight wall portions can be four, five, six, or other numbers, selected according to actual needs; no specific requirements are specified here.

[0046] The first chamfer is straight, meaning its cross-sectional shape is a straight line, not an arc. The length of the first chamfer is 1.5-10mm, selected according to actual needs; no specific requirements are specified here. The first straight wall is also straight, meaning its cross-sectional shape is a straight line. This straight-line first chamfer facilitates the preparation of chamfered monocrystalline silicon wafers after cutting monocrystalline silicon rods. Furthermore, the straight-line chamfer of the monocrystalline silicon wafer ensures proper positioning during cell fabrication and module assembly, resulting in good positioning performance, reduced misalignment, and guaranteed quality of the fabricated cells and modules.

[0047] The line connecting one end of the first chamfered portion to the center point of the cross-section of the silicon rod body and the silicon rod body <110> The angle between crystal orientations is not less than 0.35° and not greater than 3.2°. That is, at the cross-section of the silicon rod body, the straight line formed by connecting the endpoint of any end of the first chamfer portion of the silicon rod body to the center point of the silicon rod body is perpendicular to the silicon rod body. <110> The angle between crystal orientations is not less than 0.35° and not greater than 3.2°. A straight line connecting any end of the first chamfer at the cross-section of the silicon rod body to the center point of the cross-section of the silicon rod body is defined as intersecting the silicon rod body... <110> If the angle between crystal orientations is θ, then 0.35°≤θ≤3.2°.

[0048] The length of the first chamfer is calculated based on θ and the side length and diameter of the silicon rod body.

[0049] The following explanation uses an example where there are four first straight walls. When there are four first straight walls, there are also four first chamfered sections. The first straight walls and the first chamfered sections are connected alternately, end to end, forming the shape of a single-crystal silicon rod. This single-crystal silicon rod has a quadrilateral structure, with its four edges chamfered at right angles, forming straight lines and constituting the first chamfered sections. <110> The crystal orientation coincides with the diagonal of the cross-section of the silicon rod body.

[0050] The two ends of the first chamfer are respectively aligned with the center point of the cross-section of the silicon rod body, and the angle between the two lines is called the central angle A. When the median of the central angle A coincides with the diagonal of the cross-section of the silicon rod body, that is, when the median of the central angle A coincides with the diagonal of the cross-section of the silicon rod body... <110> If the crystal orientations coincide, then let half of the central angle A be the same as θ. The angle θ is not less than 0.35° and not greater than 3.2°. Therefore, the angle A corresponding to the center of the cross-section of the first chamfered portion and the silicon rod body is not less than 0.7° and not greater than 6.4°. In other words, the angle A is not less than 0.7° and not greater than 6.4°. That is, one end of the first chamfered portion forms a straight line with the center point of the cross-section of the silicon rod body. The angle between this straight line and the diagonal of the silicon wafer body is θ. This angle θ is greater than 0.35° and less than 3.2°. The closer the straight line formed by the first chamfered portion and the center point of the cross-section of the silicon rod body is to the diagonal, the smaller the angle θ. The farther the straight line formed by the first chamfered portion and the center point of the cross-section of the silicon rod body is from the diagonal, the larger the angle θ.

[0051] When the median of central angle A does not coincide with the diagonal of the cross-section of the silicon rod body, that is, when the median of central angle A does not coincide with the diagonal of the cross-section of the silicon rod body... <110> The crystal orientations do not coincide, and either end of the first chamfer is aligned with the center point of the cross-section of the silicon rod body, forming a straight line with the silicon rod body. <110> The angle between the crystal orientations is θ, where 0.35° ≤ θ ≤ 3.2°. In this case, the other end of the first chamfer is aligned with the center point of the cross-section of the silicon rod body, forming a straight line with the silicon rod body. <110> The angle between crystal orientations is not the same as θ.

[0052] The side length, number of sides, and length of the silicon rod body are selected according to actual needs, and no specific requirements are specified here.

[0053] The crystal orientation along the axial direction of the silicon rod body is <100> .

[0054] The length of chamfer 2 is 1.5-10mm, which can be selected according to actual needs. No specific requirements are given here.

[0055] A method for preparing a single-crystal silicon rod, used to prepare the aforementioned single-crystal silicon rod, such as... Figure 4 As shown, it includes the following steps:

[0056] The single-crystal wafer is squared to form multiple first straight walls and multiple edges: The single-crystal wafer formed by Czochralski-grown single crystal is cut using diamond wire to remove the edge layer, forming a polygonal prism with multiple first straight walls and edges. The number of first straight walls is selected according to actual needs and is not specifically required here. When there are four first straight walls, the single-crystal wafer, after being cut, forms a square bar, which has a cuboid structure.

[0057] The edges of the squared single-crystal wafer are chamfered. During chamfering, a grinding wheel is used to polish the edges. Figure 4 As shown in the diagram, v1 represents the silicon rod feed direction, and v3 represents the grinding wheel rotation direction. During the grinding process, the grinding wheel rotates, and the squared single-crystal wafer is fed in a translational manner without rotating. That is, when grinding the edges of the squared single-crystal silicon rod, a diamond grinding wheel is used on the grinding machine to grind the edges, straightening the sharp corners and creating a chamfer to form a first chamfer. This first chamfer is a right angle and has a straight shape. During the grinding process, the grinding wheel rotates, and the single-crystal silicon rod is fed in a translational manner without rotating. The diamond grinding wheel grinds along the length of the single-crystal silicon rod to avoid inconsistent grinding defects.

[0058] After the single-crystal silicon rod is prepared, it is cut to prepare the single-crystal silicon wafers described above.

[0059] A solar cell includes the aforementioned monocrystalline silicon wafer, which is fabricated using shingled silicon technology, PERC technology, or other cell technologies, depending on the specific requirements. The monocrystalline silicon wafer has a chamfered portion 2, which is straight, facilitating positioning during the solar cell fabrication process. Particularly during grid line printing, the straight chamfered portion 2 of the monocrystalline silicon wafer easily aligns with the printing mold, ensuring good positioning during printing.

[0060] A solar cell module includes the aforementioned solar cells, which are composed of multiple solar cells. The module is assembled from multiple large-size monocrystalline silicon wafers. During the manufacturing process of the module, the alignment of each solar cell is facilitated by the straight chamfered portion 2, which facilitates positioning during the manufacturing process and provides good positioning effect.

[0061] A solar cell strip is made by cutting the aforementioned solar cells. The solar cells can be cut into multiple solar cell strips, which can be two, four, five, or other quantities, depending on the actual needs. The number of cuts can be one, two, or multiple, depending on the actual needs.

[0062] A shingled battery module includes multiple shingled battery strings, each shingled battery string comprising multiple solar cell strips as described above.

[0063] Example 1

[0064] A single-crystal silicon wafer includes a wafer body, which comprises multiple straight-walled portions 1 and multiple chamfered portions 2. The straight-walled portions 1 and chamfered portions 2 are connected end-to-end alternately. The chamfered portions 2 are straight lines with a length of 1.53 mm. A straight line formed by connecting the endpoint of any chamfered portion 2 of the wafer body to the center point of the wafer body is perpendicular to the wafer body. <110> The angle between the crystal orientations is 0.33°, and the angle A corresponding to the center of the chamfered portion 2 and the center of the silicon wafer body is 0.65°. The midline of this central angle A coincides with the diagonal G of the silicon wafer body. Let θ be half of this central angle A, and let the crystal orientation in the thickness direction of the silicon wafer body be... <100> .

[0065] A single-crystal silicon rod includes a silicon rod body, which is wire-cut into multiple single-crystal silicon wafers as described above. The silicon rod body has a rod structure with a certain length, and its cross-sectional shape is adapted to the shape of the single-crystal silicon wafers. The silicon rod body includes multiple first straight walls and multiple first chamfered sections, which are alternately connected end-to-end. The first chamfered sections are straight lines with a length of 1.53 mm. A straight line formed by connecting any endpoint of the first chamfered section to the center point of the cross-section of the silicon rod body is perpendicular to the cross-section of the silicon rod body. <110> The angle between the crystal orientations is 0.33°. The crystal orientation along the axial direction of the silicon rod body is... <100> .

[0066] A solar cell includes a plurality of the above-described monocrystalline silicon wafers, which are fabricated from the monocrystalline silicon wafers.

[0067] A solar panel comprising a plurality of the aforementioned solar cells, wherein the panel is composed of the plurality of the aforementioned solar cells.

[0068] A solar cell strip is made by cutting the aforementioned solar cells. The solar cells can be cut into multiple solar cell strips, which can be two, four, five, or other quantities, depending on the actual needs. The number of cuts can be one, two, or multiple, depending on the actual needs.

[0069] A shingled battery module includes multiple shingled battery strings, each shingled battery string comprising multiple solar cell strips as described above.

[0070] Example 2

[0071] A single-crystal silicon wafer includes a silicon wafer body, which comprises multiple straight-walled portions 1 and multiple chamfered portions 2. The straight-walled portions 1 and chamfered portions 2 are connected end-to-end alternately. The chamfered portions 2 are straight lines with a length of 10 mm. A straight line formed by connecting the endpoint of any chamfered portion 2 of the silicon wafer body to the center point of the silicon wafer body is perpendicular to the silicon wafer body. <110> The angle between the crystal orientations is 3.2°, and the angle A corresponding to the center of the chamfered portion 2 and the center of the silicon wafer body is 6.4°. The midline of this central angle A coincides with the diagonal G of the silicon wafer body. Let θ be half of this central angle A, and let the crystal orientation in the thickness direction of the silicon wafer body be... <100> .

[0072] A single-crystal silicon rod includes a silicon rod body, which is wire-cut into multiple single-crystal silicon wafers as described above. The silicon rod body has a rod structure with a certain length, and its cross-sectional shape is adapted to the shape of the single-crystal silicon wafers. The silicon rod body includes multiple first straight wall portions and multiple first chamfer portions, which are alternately connected end-to-end. The first chamfer portions are straight lines with a length of 10 mm. A straight line formed by connecting any endpoint of the first chamfer portion to the center point of the cross-section of the silicon rod body is perpendicular to the cross-section of the silicon rod body. <110> The angle between the crystal orientations is 3.2°. The crystal orientation along the axial direction of the silicon rod body is... <100> .

[0073] A solar cell includes a plurality of the above-described monocrystalline silicon wafers, which are fabricated from the monocrystalline silicon wafers.

[0074] A solar panel comprising a plurality of the aforementioned solar cells, wherein the panel is composed of the plurality of the aforementioned solar cells.

[0075] A solar cell strip is made by cutting the aforementioned solar cells. The solar cells can be cut into multiple solar cell strips, which can be two, four, five, or other quantities, depending on the actual needs. The number of cuts can be one, two, or multiple, depending on the actual needs.

[0076] A shingled battery module includes multiple shingled battery strings, each shingled battery string comprising multiple solar cell strips as described above.

[0077] Example 3

[0078] A single-crystal silicon wafer includes a silicon wafer body, which comprises multiple straight-walled portions 1 and multiple chamfered portions 2. The straight-walled portions 1 and chamfered portions 2 are connected end-to-end alternately. The chamfered portions 2 are straight lines with a length of 1.99 mm. A straight line formed by connecting the endpoint of any chamfered portion 2 of the silicon wafer body to the center point of the silicon wafer body is perpendicular to the silicon wafer body. <110> The angle between the crystal orientations is 0.39°, and the angle A corresponding to the center of the chamfered portion 2 and the center of the silicon wafer body is 0.77°. The midline of this central angle A coincides with the diagonal G of the silicon wafer body. Let θ be half of this central angle A, and let the crystal orientation in the thickness direction of the silicon wafer body be... <100> .

[0079] A single-crystal silicon rod includes a silicon rod body, which is wire-cut to form multiple single-crystal silicon wafers. The silicon rod body has a rod structure with a certain length, and its cross-sectional shape is adapted to the shape of the single-crystal silicon wafers. The silicon rod body includes multiple first straight walls and multiple first chamfered sections, which are alternately connected end-to-end. The first chamfered sections are straight lines with a length of 1.99 mm. A straight line formed by connecting any endpoint of the first chamfered section to the center point of the cross-section of the silicon rod body is perpendicular to the cross-section of the silicon rod body. <110> The angle between the crystal orientations is 0.39°. The crystal orientation along the axial direction of the silicon rod body is... <100> .

[0080] A solar cell includes a plurality of the above-described monocrystalline silicon wafers, which are fabricated from the monocrystalline silicon wafers.

[0081] A solar panel comprising a plurality of the aforementioned solar cells, wherein the panel is composed of the plurality of the aforementioned solar cells.

[0082] A solar cell strip is made by cutting the aforementioned solar cells. The solar cells can be cut into multiple solar cell strips, which can be two, four, five, or other quantities, depending on the actual needs. The number of cuts can be one, two, or multiple, depending on the actual needs.

[0083] A shingled battery module includes multiple shingled battery strings, each shingled battery string comprising multiple solar cell strips as described above.

[0084] Example 4

[0085] A single-crystal silicon wafer includes a silicon wafer body, which comprises multiple straight-walled portions 1 and multiple chamfered portions 2. The straight-walled portions 1 and chamfered portions 2 are connected end-to-end alternately. The chamfered portions 2 are straight lines with a length of 1.85 mm. A straight line formed by connecting the endpoint of any chamfered portion 2 of the silicon wafer body to the center point of the silicon wafer body is perpendicular to the silicon wafer body. <110> The angle between the crystal orientations is 0.38°, and the angle A corresponding to the center of the chamfered portion 2 and the center of the silicon wafer body is 0.75°. The midline of this central angle A coincides with the diagonal G of the silicon wafer body. Let θ be half of this central angle A, and let the crystal orientation in the thickness direction of the silicon wafer body be... <100> .

[0086] A single-crystal silicon rod includes a silicon rod body, which is wire-cut into multiple single-crystal silicon wafers as described above. The silicon rod body has a rod structure with a certain length, and its cross-sectional shape is adapted to the shape of the single-crystal silicon wafers. The silicon rod body includes multiple first straight walls and multiple first chamfered sections, which are alternately connected end-to-end. The first chamfered sections are straight lines with a length of 1.85 mm. A straight line formed by connecting any endpoint of the first chamfered section to the center point of the cross-section of the silicon rod body is perpendicular to the cross-section of the silicon rod body. <110> The angle between the crystal orientations is 0.38°. The crystal orientation along the axial direction of the silicon rod body is... <100> .

[0087] A solar cell includes a plurality of the above-described monocrystalline silicon wafers, which are fabricated from the monocrystalline silicon wafers.

[0088] A solar panel comprising a plurality of the aforementioned solar cells, wherein the panel is composed of the plurality of the aforementioned solar cells.

[0089] A solar cell strip is made by cutting the aforementioned solar cells. The solar cells can be cut into multiple solar cell strips, which can be two, four, five, or other quantities, depending on the actual needs. The number of cuts can be one, two, or multiple, depending on the actual needs.

[0090] A shingled battery module includes multiple shingled battery strings, each shingled battery string comprising multiple solar cell strips as described above.

[0091] Example 5

[0092] A monocrystalline silicon wafer includes a wafer body, which comprises multiple straight-walled portions 1 and multiple chamfered portions 2. The straight-walled portions 1 and chamfered portions 2 are connected end-to-end alternately. The chamfered portions 2 are straight lines with a length of 3.27 mm. A straight line formed by connecting the endpoint of any chamfered portion 2 of the wafer body to the center point of the wafer body is perpendicular to the wafer body. <110> The angle between the crystal orientations is 0.78°, and the angle A corresponding to the center of the chamfered portion 2 and the center of the silicon wafer body is 1.56°. The midline of this central angle A coincides with the diagonal G of the silicon wafer body. Let θ be half of this central angle A, and let the crystal orientation in the thickness direction of the silicon wafer body be... <100> .

[0093] A single-crystal silicon rod includes a silicon rod body, which is wire-cut into multiple single-crystal silicon wafers as described above. The silicon rod body has a rod structure with a certain length, and its cross-sectional shape is adapted to the shape of the single-crystal silicon wafers. The silicon rod body includes multiple first straight walls and multiple first chamfered sections, which are alternately connected end-to-end. The first chamfered sections are straight lines with a length of 3.27 mm. A straight line formed by connecting any endpoint of the first chamfered section to the center point of the cross-section of the silicon rod body is perpendicular to the cross-section of the silicon rod body. <110> The angle between the crystal orientations is 0.78°. The crystal orientation along the axial direction of the silicon rod body is... <100> .

[0094] A solar cell includes a plurality of the above-described monocrystalline silicon wafers, which are fabricated from the monocrystalline silicon wafers.

[0095] A solar panel comprising a plurality of the aforementioned solar cells, wherein the panel is composed of the plurality of the aforementioned solar cells.

[0096] A solar cell strip is made by cutting the aforementioned solar cells. The solar cells can be cut into multiple solar cell strips, which can be two, four, five, or other quantities, depending on the actual needs. The number of cuts can be one, two, or multiple, depending on the actual needs.

[0097] A shingled battery module includes multiple shingled battery strings, each shingled battery string comprising multiple solar cell strips as described above.

[0098] Example 6

[0099] A single-crystal silicon wafer includes a silicon wafer body, which comprises multiple straight-walled portions 1 and multiple chamfered portions 2. The straight-walled portions 1 and chamfered portions 2 are connected end-to-end alternately. The chamfered portions 2 are straight lines with a length of 5.31 mm. A straight line formed by connecting the endpoint of any chamfered portion 2 of the silicon wafer body to the center point of the silicon wafer body is perpendicular to the silicon wafer body. <110> The angle between the crystal orientations is 0.95°, and the angle A corresponding to the center of the chamfered portion 2 and the center of the silicon wafer body is 1.90°. The midline of this central angle A coincides with the diagonal G of the silicon wafer body. Let θ be half of this central angle A, and let the crystal orientation in the thickness direction of the silicon wafer body be... <100> .

[0100] A single-crystal silicon rod includes a silicon rod body, which is wire-cut into multiple single-crystal silicon wafers as described above. The silicon rod body has a rod structure with a certain length, and its cross-sectional shape is adapted to the shape of the single-crystal silicon wafers. The silicon rod body includes multiple first straight wall portions and multiple first chamfered portions, which are alternately connected end-to-end. The first chamfered portions are straight lines with a length of 5.31 mm. A straight line formed by connecting any endpoint of the first chamfered portion to the center point of the cross-section of the silicon rod body is perpendicular to the cross-section of the silicon rod body. <110> The angle between the crystal orientations is 0.95°. The crystal orientation along the axial direction of the silicon rod body is... <100> .

[0101] A solar cell includes a plurality of the above-described monocrystalline silicon wafers, which are fabricated from the monocrystalline silicon wafers.

[0102] A solar panel comprising a plurality of the aforementioned solar cells, wherein the panel is composed of the plurality of the aforementioned solar cells.

[0103] A solar cell strip is made by cutting the aforementioned solar cells. The solar cells can be cut into multiple solar cell strips, which can be two, four, five, or other quantities, depending on the actual needs. The number of cuts can be one, two, or multiple, depending on the actual needs.

[0104] A shingled battery module includes multiple shingled battery strings, each shingled battery string comprising multiple solar cell strips as described above.

[0105] By adopting the above technical solution, the single crystal rods of Czochralski-grown single crystals are squared and chamfered to prepare single crystal silicon rods, and then the single crystal silicon rods are wire-cut to prepare single crystal silicon wafers. When chamfering the single crystal silicon rods, a grinding wheel is used to grind the edges of the squared single crystal silicon rods to form chamfered parts. During the grinding process, the single crystal silicon rod itself does not rotate, but only performs axial feeding. The grinding wheel rotates to grind the edges of the single crystal silicon rods, which makes the grinding curvature of the single crystal silicon rods very consistent and controllable, avoiding any impact on the quality of the single crystal silicon wafers and improving the yield of single crystal silicon wafers.

[0106] Because the above-mentioned method of polishing the edges of the monocrystalline silicon rod is used, the monocrystalline silicon rod has a first chamfer, and the first chamfer is straight, which makes it easy to control the shape of the chamfer of the monocrystalline silicon wafer after the monocrystalline silicon rod is cut.

[0107] The wire-cut monocrystalline silicon wafers have chamfered edges, and the chamfered edges are straight lines. This facilitates the positioning of the monocrystalline silicon wafers during downstream battery electrode printing and battery module assembly, resulting in good positioning performance and preventing misalignment during wafer splicing. Furthermore, the straight line formed by connecting any endpoint of the chamfered edge to the center point of the monocrystalline silicon wafer... <110> The angle between crystal orientations is limited to reduce the breakage rate of monocrystalline silicon wafers.

[0108] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A single-crystal silicon wafer, comprising a silicon wafer body, characterized in that: The silicon wafer body includes multiple straight-walled portions and multiple chamfered portions, which are connected end-to-end alternately. Each chamfered portion is a straight line, and the straight line formed by connecting any end of the chamfered portion to the center point of the silicon wafer body is perpendicular to the silicon wafer body. <110> The angle between crystal orientations is not less than 0.35° and not greater than 3.2°; the length of the chamfered portion is 1.5-10mm; the single-crystal silicon wafer... <110> The crystal orientation coincides with the diagonal of the silicon wafer body.

2. The single-crystal silicon wafer according to claim 1, characterized in that: The crystal orientation along the thickness direction of the silicon wafer body is <100> .

3. The single-crystal silicon wafer according to claim 2, characterized in that: A straight line connecting the endpoint of either end of the chamfered portion to the center point of the silicon wafer body intersects with the silicon wafer body. <110> The angle between the crystal orientations is 0.39°.

4. The single-crystal silicon wafer according to claim 2, characterized in that: The number of straight wall sections is four, and the number of chamfered sections is four.

5. A single-crystal silicon rod, characterized in that: The silicon rod body includes a silicon rod body that is wire-cut into multiple single-crystal silicon wafers as described in any one of claims 1-4. The silicon rod body includes multiple first straight-wall portions and multiple first chamfer portions, with the first straight-wall portions and the first chamfer portions connected end-to-end alternately. The first chamfer portions are straight lines, and a line connecting any end of a first chamfer portion to the center point of the cross-section of the silicon rod body intersects with the silicon rod body. <110> The angle between crystal orientations is not less than 0.35° and not greater than 3.2°, and the length of the first chamfer is 1.5-10mm.

6. The single-crystal silicon rod according to claim 5, characterized in that: The axial crystal orientation index of the silicon rod body is <100> .

7. A method for preparing a single-crystal silicon rod, used to prepare the single-crystal silicon rod as described in any one of claims 5-6, characterized in that: Includes the following steps, The single crystal wafer is cut into square shapes to form multiple straight-walled sections and multiple edges; The edges of the squared single-crystal rod are chamfered, and the chamfer is a right angle.

8. The method for preparing a single-crystal silicon rod according to claim 7, characterized in that: When chamfering the edge, a grinding wheel is used to grind the edge. During the grinding process, the grinding wheel rotates, and the squared single crystal rod is fed by translation without rotating.

9. A solar cell, characterized in that, Including the monocrystalline silicon wafers as described in claims 1-4.

10. A solar cell module, characterized in that, Including the solar cell as described in claim 9.

11. A solar cell strip, characterized in that, It is made by cutting the solar cell as described in claim 10.

12. A shingled battery module, characterized in that, It includes multiple shingled battery strings, each comprising multiple solar cell strips as described in claim 11.

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