Silicon wafer and processing method thereof, battery piece and solar battery assembly

Abstract

The embodiment of the invention relates to the field of photovoltaic modules, and relates to a silicon wafer and a processing method thereof, a battery piece and a solar cell module, and the processing method of the silicon wafer comprises the following steps: cutting a monocrystalline silicon rod for the first time to obtain a central silicon block; the center silicon block is cut for the second time to obtain a silicon wafer, the deflection angle of the cutting face of the second time of cutting relative to the crystal face (100) of the single crystal silicon rod is theta 2, and theta 2 meets 0 degree lt; [theta] 2lt; theta 2 is not equal to 45 degrees; and performing alkali texturing on the surface of the silicon wafer to form a pyramid structure, thereby obtaining the silicon wafer with the pyramid structure. The battery piece prepared by the silicon wafer with the pyramid structure can be matched with the installation inclination angle requirements of the solar battery assembly in different latitudes or specific scenes, a corresponding inclination angle does not need to be adjusted and set through a support, the reflectivity of the battery piece is reduced, and the light absorption effect is better.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic modules, and in particular to a silicon wafer and a processing method thereof, a solar cell and a solar cell module. Background Art

[0002] At present, the crystal rod is first processed into a silicon block with a (100) crystal plane, and then cut into silicon wafers with a (100) crystal plane by diamond wire. The silicon wafer with a (100) crystal plane is formed into a positive pyramid structure after alkali texturing, and then packaged into a component with a positive pyramid structure after being made into a battery.

[0003] In different latitudes, the angle between sunlight and the ground is different. In related technologies, when installing components with a positive pyramid structure, the installation angle needs to be adjusted according to the latitude so that the sunlight can shine vertically on the components. Only then can the positive pyramid structure of the components absorb the maximum amount of light, and the power generation is the highest at this time.

[0004] However, the inventors realize that in operation / actual use, the installation of components in different latitudes and specific scenarios requires adjustment of the brackets and setting of corresponding inclination angles, which has the following defects: it is inconvenient to design and install in areas with complex terrain. Summary of the invention

[0005] One or more embodiments of the present application provide a photovoltaic module installation system to solve or at least partially alleviate the problem in the related art that it is inconvenient to install modules with a pyramid structure in areas with complex terrain.

[0006] In a first aspect of the present application, a method for processing a silicon wafer is provided, which adopts the following technical solution:

[0007] A method for processing a silicon wafer comprises the following steps:

[0008] Performing a first cut on the single crystal silicon rod to obtain a central silicon block;

[0009] The central silicon block is cut for the second time to obtain a silicon wafer, and the cutting surface of the second cutting is deflected by an angle θ2 relative to the (100) crystal plane of the single crystal silicon rod, and θ2 satisfies 0°<θ2<90° and θ2≠45°;

[0010] The surface of the silicon wafer is subjected to alkali texturing to form a pyramid structure, thereby obtaining a silicon wafer having a pyramid structure.

[0011] By adopting the above technical scheme, according to the latitude of solar cell assembly installation or the inclination requirement of a specific scene (such as the exterior wall of a building), the single crystal silicon rod is cut for the first time to obtain a central silicon block, and then the central silicon block is cut for the second time to obtain a silicon wafer, and the deflection angle of the cut surface of the obtained silicon wafer relative to the (100) crystal plane of the single crystal silicon rod is θ2, θ2 satisfies 0°<θ2<90° and θ2≠45°, so as to obtain a silicon wafer with a deflected textured surface, and the deflected textured surface of the silicon wafer is subjected to alkali texture processing to obtain a silicon wafer with a pyramid structure; because no matter how the actual (100) crystal plane of the silicon wafer is deflected, the pyramid structure of the silicon wafer processed by alkali texture processing is always a positive pyramid with the midline perpendicular to the (100) crystal plane, and the silicon wafer is used to process the pyramid structure. The surface of the structure or the main structure below the pyramid structure of the silicon wafer has a deflection angle relative to the (100) crystal plane, resulting in the pyramid structure also having a deflection angle relative to the main structure of the silicon wafer, that is, the pyramid structure formed on the surface of the silicon wafer is actually a pyramid structure inclined relative to the processing surface of the silicon wafer. Therefore, the deflection of the cutting surface of the silicon wafer causes the physical visual deflection of the pyramid structure, so that the battery cell prepared by the silicon wafer can match the installation inclination angle requirements of solar cell modules in different latitudes or specific scenes (such as building exterior walls), and there is no need to adjust and set the corresponding inclination angle through the bracket, which solves the problem of inconvenient design and installation of solar cell modules with positive pyramid structures in areas with complex terrain. In addition, the battery cell prepared by the silicon wafer can reduce the light reflectivity and have a better light absorption effect.

[0012] In one embodiment, a single crystal silicon rod is cut for the first time to obtain a central silicon block, comprising: cutting the single crystal silicon rod for the first time along a direction parallel to the

[001] crystal band axis of the single crystal silicon rod, wherein the cutting surface of the first cut is deflected by an angle θ1 around the

[001] crystal band axis relative to the (100) crystal plane of the single crystal silicon rod, and θ1 satisfies 0°<θ1<90° and θ1≠45°.

[0013] In one embodiment, cutting the central silicon block for a second time to obtain silicon wafers includes: cutting the central silicon block along a cutting plane parallel to the first cutting to obtain silicon wafers.

[0014] In one embodiment, the central silicon block is cut a second time to obtain a silicon wafer, including: cutting the central silicon block along a cutting plane intersecting the

[001] crystal axis to obtain a silicon wafer.

[0015] In one embodiment, before alkali texturing is performed on the surface of the silicon wafer to form the pyramid structure, the following steps are also included:

[0016] The edge skin obtained after the first cutting is cut for the third time to remove the arc top material and the edge ear material of the edge skin to obtain the edge skin silicon block;

[0017] The edge silicon block is cut for the fourth time to obtain a silicon wafer, and the cutting surface of the fourth cutting is deflected by an angle θ3 relative to the (100) crystal plane of the single crystal silicon rod, and θ3 satisfies 0°<θ3<90° and θ3≠45°.

[0018] The edge skin material is used to prepare silicon wafers with a pyramid structure, so that the utilization rate of raw materials is improved and costs are saved.

[0019] In one embodiment, the edge silicon block is cut for the fourth time to obtain the silicon wafer, comprising: slicing the edge silicon block parallel to the cutting plane of the first cutting to obtain the silicon wafer.

[0020] In one embodiment, the edge silicon block is cut for the fourth time to obtain silicon wafers, including: stacking and solidifying multiple edge silicon blocks in sequence along a direction perpendicular to the cutting surface of the first cutting, cutting and truncating along the stacking direction to obtain production silicon blocks, and slicing the production silicon blocks perpendicular to the stacking direction to obtain silicon wafers.

[0021] Specifically, after the edge skin silicon block is cut, the size does not meet the actual industrial production needs. Multiple edge skin silicon blocks with deflected velvet surfaces are stacked and solidified, and then sliced ​​to obtain production silicon wafers required by actual industrial production.

[0022] In a second aspect of the present application, a silicon wafer is provided, which adopts the following technical solution:

[0023] The surface of the silicon wafer having the pyramid structure is a (hk0) crystal plane having a deflection angle relative to the (100) crystal plane of the single crystal silicon rod.

[0024] By adopting the above technical scheme, a silicon wafer with a pyramid structure, no matter how the actual (100) crystal plane of the silicon wafer is deflected, the pyramid structure processed by alkali texturing of the silicon wafer is always a positive pyramid with the center line perpendicular to the (100) crystal plane relative to the (100) crystal plane, and the surface of the main structure below the pyramid structure of the silicon wafer is the (hk0) crystal plane, which has a deflection angle relative to the (100) crystal plane, resulting in the pyramid structure having a deflection angle relative to the main structure of the silicon wafer. A pyramid structure is formed on the surface of the silicon wafer, so the deflection of the deflected texturing surface of the silicon wafer causes the physical visual deflection of the pyramid structure, and there is no need to adjust and set the corresponding inclination angle through a bracket, thereby solving the problem of inconvenient design and installation of solar cell modules with a positive pyramid structure in areas with complex terrain, and the reflectivity of the solar cell prepared by the silicon wafer with the pyramid structure is reduced, and the light absorption effect is better.

[0025] The third aspect of the present application provides a battery cell, which adopts the following technical solution:

[0026] Including the above-mentioned silicon wafer.

[0027] By adopting the above technical solution, the reflectivity of the cell made of silicon wafers with a pyramid structure is reduced, and the light absorption effect is better. The cell can match the installation inclination requirements of solar cell modules in different latitudes or specific scenes (such as building exterior walls), and does not need to adjust and set the corresponding inclination through the bracket, which solves the problem of inconvenience in designing and installing solar cell modules with a pyramid structure in areas with complex terrain. By adopting the above technical solution, the reflectivity of the cell is lower than that of a normal cell, that is, the light absorption is better.

[0028] In a fourth aspect of the present application, a solar cell assembly is provided, which adopts the following technical solution:

[0029] It includes a back plate and the above-mentioned battery cell.

[0030] By adopting the above technical solution, solar cell modules can match the installation inclination requirements of different latitudes or specific scenes (such as building exterior walls), without the need to adjust and set the corresponding inclination through the bracket, thus solving the problem of inconvenient design and installation of solar cell modules with a pyramid structure in areas with complex terrain. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present application, rather than limiting the present application.

[0032] Figure 1 Schematic diagram of the structure of a single crystal silicon rod according to some embodiments of the present application.

[0033] Figure 2 It is a schematic diagram of a square cutting method for processing a silicon wafer with a pyramid structure according to some embodiments of the present application.

[0034] Figure 3 Schematic diagram of a crystal plane index (HK0) of a silicon wafer surface at a deflection angle θ according to some embodiments of the present application.

[0035] Figure 4 Schematic diagram of the pyramid structure observed in 2D and 3D corresponding to different deflection angles θ of the silicon wafer crystal plane according to some embodiments of the present application.

[0036] Figure 5 Schematic diagram of a silicon wafer crystal plane when the deflection angle θ=45° in 2D according to some embodiments of the present application.

[0037] Figure 6 Schematic diagram of the pyramid structure of a silicon wafer crystal plane observed in 3D when the deflection angle θ=45° according to some embodiments of the present application.

[0038] Figure 7This is a schematic diagram of a silicon block obtained by performing a second cut on the central silicon block according to some embodiments of the present application.

[0039] Figure 8 Schematic diagram of edge cutting of a method for processing a silicon wafer with a pyramid structure according to some embodiments of the present application.

[0040] Fig. 9 A flow chart of stacking and curing silicon wafers according to some embodiments of the present application to obtain silicon wafers for production.

[0041] Fig.10 This is a schematic diagram of cutting an intermediate single crystal silicon rod to obtain a 210×105 edge skin according to some embodiments of the present application.

[0042] Fig.11 It is a schematic diagram comparing a normal cell and a texturing-deflected cell according to some embodiments of the present application.

[0043] Fig.12 This is a schematic diagram of a solar cell assembly with a pyramid structure having a deflection angle of θ1 according to some embodiments of the present application, which can be rotated 180 degrees vertically in the opposite direction to obtain a solar cell assembly with a pyramid structure having a deflection angle of (90°-θ1).

[0044] In the figure:

[0045] 1. Single crystal silicon rod; 11. (100) crystal plane; 12. Edge line; 13.

[001] crystal zone axis; 2. Edge skin; 21. Deflected velvet surface; 22. Arc top material; 23. Edge ear material; 3. Central silicon block; 4. Edge skin silicon block; 41. Pyramid structure; 42. Main body structure; 5. Production silicon block; 6. Tangent. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings showing multiple embodiments of the present application. It should be understood that the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments described in the present application, all other embodiments obtained by ordinary technicians in this field without spending creative work will fall within the scope of protection of the present application.

[0047] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those generally understood by technicians in the technical field of this application; the terms used in the specification of the application are only for the purpose of describing specific implementation methods, and are not intended to limit this application; the terms "including", "comprising", "having", "having", "containing", "including", etc. in the specification and claims of this application and the above-mentioned figure description are open-ended words. Therefore, "including", "comprising", "having" is a method or device with one or more steps or elements, for example, which has one or more steps or elements, but is not limited to having only these one or more elements. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned figures are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, the meaning of "multiple" is two or more.

[0048] In the description of the present application, it should be understood that the terms "center", "lateral", "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0049] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0050] One or more embodiments of the present application disclose a method for processing a silicon wafer, comprising the following steps:

[0051] Performing a first cutting on the single crystal silicon rod 1 to obtain a central silicon block 3;

[0052] The central silicon block 3 is cut for the second time to obtain a silicon wafer, and the cutting surface of the second cutting is deflected by an angle θ2 relative to the (100) crystal plane of the single crystal silicon rod 1, and θ2 satisfies 0°<θ2<90° and θ2≠45°;

[0053] The surface of the silicon wafer is subjected to alkali texturing to form a pyramid structure, thereby obtaining a silicon wafer having a pyramid structure.

[0054] Specifically, Figure 2 As shown, the single crystal silicon rod 1 is cut for the first time to obtain a central silicon block 3 extending in the same direction as the

[001] crystal axis 13, wherein the first cutting can be performed along the cutting surface composed of adjacent ridges 12 (i.e. Figure 2 The single crystal silicon rod 1 is cut by cutting the single crystal silicon rod 1. At this time, the cutting surface obtained by the first cutting is the (100) crystal plane 11; the cutting surface (i.e., the cutting surface obtained by the first cutting) can also be obtained by deflecting the (100) crystal plane of the single crystal silicon rod 1 around the

[001] crystal zone axis 13 by an angle of θ1. Figure 2 The central silicon block 3 is cut for the second time, and the deflection angle of the cut surface relative to the (100) crystal plane of the single crystal silicon rod 1 is θ2, θ2 satisfies 0°<θ2<90° and θ2≠45°, that is, the cut surface of the obtained silicon wafer has a deflection angle relative to the (100) crystal plane, and thus, a silicon wafer with a deflected textured surface 21 can be obtained.

[0055] Specifically, the crystal band axis refers to the intersection lines of all crystal planes and other planes in the same crystal band that are parallel to each other, and the parallel straight line passing through the coordinate origin is called the crystal band axis. The crystal band axis represents the characteristics of the distribution of various crystal planes in the crystal band. The crystal band axis is often used as the symbol of the crystal band, and the direction index of the crystal band axis represents the index of the crystal band. Among them, the crystal planes of the crystal band with the crystal band axis direction index

[001] are parallel to the

[001] direction, that is, each crystal plane is parallel to the c-axis of the unit cell coordinate system or the a3 axis of the primitive cell coordinate system, and the face index of each crystal plane is (hk0) or (h1h20), that is, the third number must be 0.

[0056] By adopting the above technical scheme, according to the latitude of solar cell assembly installation or the inclination angle requirement of a specific scene (such as the exterior wall of a building), the single crystal silicon rod 1 is first cut to obtain a central silicon block 3, and then the central silicon block 3 is cut for a second time to obtain a silicon wafer, and the deflection angle of the cut surface of the obtained silicon wafer relative to the (100) crystal plane of the single crystal silicon rod 1 is θ2, θ2 satisfies 0°<θ2<90° and θ2≠45°, that is, a silicon wafer with a deflected textured surface 21 is obtained, and the deflected textured surface 21 of the silicon wafer is subjected to alkali texture processing to obtain a silicon wafer with a pyramid structure; because no matter how the actual (100) crystal plane of the silicon wafer is deflected, the pyramid structure 41 of the silicon wafer processed by alkali texture processing is always a regular pyramid with a center line perpendicular to the (100) crystal plane. In this embodiment, Figure 3 As shown, the surface of the silicon wafer used to process the pyramid structure 41, or the main structure 42 below the pyramid structure 41 of the silicon wafer, has a deflection angle relative to the (100) crystal plane, resulting in the pyramid structure 41 also having a deflection angle relative to the silicon wafer main structure 42, that is, the pyramid structure formed on the surface of the silicon wafer is actually a pyramid structure inclined relative to the silicon wafer processing surface, so the deflection of the silicon wafer cutting surface causes the physical visual deflection of the pyramid structure 41, so that the battery cell prepared by the silicon wafer can match the installation inclination angle requirements of solar cell modules in different latitudes or specific scenes (such as building exterior walls), without the need to adjust and set the corresponding inclination angle through the bracket, thereby solving the problem of inconvenient design and installation of solar cell modules with positive pyramid structures in areas with complex terrain, and the battery cell prepared by the silicon wafer can reduce the light reflectivity and have a better light absorption effect.

[0057] like Figure 4 As shown, when the deflection angle θ2 of the silicon wafer cutting surface is 0°, 5°, 10°, 15°, 20°, 25° and 30° respectively, a schematic diagram of the pyramid structure 41 is observed in the 2D mode and 3D mode of the 3D drawing software. It can be seen that when the deflection angle θ2 of the silicon wafer cutting surface is 5°, 10°, 15°, 20°, 25° and 30°, an inclined pyramid structure is obtained. However, when the deflection angle of the silicon wafer cutting surface is θ2 = 0° and 90°, the cutting surface of the silicon wafer is the (100) crystal plane 11, so the obtained pyramid after alkali texturing is still a positive pyramid; when θ2 = 45°, as shown in Figure 5 and Figure 6 As shown, the cutting surface of the silicon wafer is a (110) crystal plane. In this case, no pyramid appears after texturing, but only an edge face composed of two (111) faces.

[0058] The first cutting and the second cutting mentioned above as well as the third cutting and the fourth cutting mentioned later only indicate different times of cutting in the processing method and do not limit the process operation sequence.

[0059] In some embodiments, the single crystal silicon rod 1 is cut for the first time to obtain the central silicon block 3, including: cutting the single crystal silicon rod 1 for the first time along a direction parallel to the

[001] crystal zone axis 13 of the single crystal silicon rod 1, the cutting surface of the first cut is deflected by an angle θ1 around the

[001] crystal zone axis 13 relative to the (100) crystal plane of the single crystal silicon rod 1, and θ1 satisfies 0°<θ1<90° and θ1≠45°.

[0060] Specifically, Figure 2 As shown, the single crystal silicon rod 1 is cut for the first time along a direction parallel to the

[001] crystal zone axis 13 of the single crystal silicon rod 1, and a central silicon block 3 extending in the same direction as the

[001] crystal zone axis 13 can be obtained. In this embodiment, the single crystal silicon rod 1 having four (100) crystal planes parallel to the crystal zone axis 13 is taken as an example. Figure 2 The solid line in is the intersection of the four (100) crystal planes and the end face 11 of the single crystal silicon rod 1. Figure 2 The dotted lines in the figure are the four intersection lines of the four cutting surfaces of the first cutting and the end surface 11 of the single crystal silicon rod 1. Figure 2 It can be seen that the four cutting surfaces of the first cutting are deflected by an angle θ1 about the

[001] crystal zone axis 13 relative to the four (100) crystal planes of the single crystal silicon rod 1; the single crystal silicon rod 1 is cut for the first time, such as Figure 3 As shown, at this time θ1 satisfies 0°<θ1<90° and θ1≠45°, then the cutting surface obtained by the first cutting is the (HK0) crystal plane, that is, the four cutting surfaces obtained by the first cutting of the central silicon block 3 are all deflected textured surfaces 21.

[0061] Specifically, when the deflection angle θ1=0° and 90° relative to the (100) crystal plane, the obtained silicon wafer cut surface is still the (100) crystal plane 11, and the alkali texturing still obtains a positive pyramid; and when the deflection angle θ1=45° relative to the (100) crystal plane, the obtained silicon wafer cut surface is the (110) crystal plane, and this texturing does not produce a pyramid, but only an edge face composed of two (111) faces. When the deflection angle θ1 satisfies the conditions of 0°<θ1<90° and θ1≠45°, an inclined pyramid structure can be obtained.

[0062] In some embodiments, the central silicon block 3 is cut a second time to obtain silicon wafers, including: cutting the central silicon block 3 along a cutting plane parallel to the first cutting to obtain silicon wafers.

[0063] Specifically, the cutting surface of the central silicon block 3 in the first cutting is the deflected texturing surface 21, and the central silicon block 3 is sliced ​​parallel to the cutting surface of the first cutting. The cutting surfaces produced by the slicing are also the deflected texturing surfaces 21, thereby obtaining a silicon wafer with a deflected texturing surface 21. Alkali texturing is performed on the deflected texturing surface 21 of the silicon wafer to form an inclined pyramid structure, thereby obtaining a silicon wafer with an inclined pyramid structure.

[0064] In some embodiments, the central silicon block 3 is cut a second time to obtain a silicon wafer, including: cutting the central silicon block 3 along a cutting plane intersecting the

[001] crystal axis 13 to obtain a silicon wafer.

[0065] Specifically, Figure 1 As shown, the end face of the single crystal silicon rod 1 is connected to the (100) crystal plane 11 which is intersected with the ridge line 12 of the single crystal silicon rod 1; Figure 7 As shown, the surface surrounded by the dotted line represents the cutting surface for the second cutting of the central silicon block 3, and the cutting surface intersects with the

[001] crystal zone axis 13. The deflection angle of the cutting surface relative to the two end surfaces of the single crystal silicon rod 1 is the deflection angle θ2 of the cutting surface for the second cutting, as shown in FIG. Figure 7As shown, the cutting surface of the second cutting is deflected at an angle θ2 in the clockwise direction relative to the (100) crystal plane 11, and the silicon block is cut multiple times parallel to the cutting surface to obtain a silicon wafer. The cutting surfaces of the silicon wafer are all deflected texturing surfaces 21. The deflected texturing surfaces 21 of the silicon wafer are alkali texturing to form a pyramid structure, so that a silicon wafer with an inclined pyramid structure can be obtained.

[0066] In some embodiments, before alkali texturing is performed on the surface of the silicon wafer to form the pyramid structure, the following steps are also included:

[0067] The edge skin 2 obtained after the first cutting is cut for the third time to remove the arc top material 22 and the edge ear material 23 of the edge skin 2 to obtain the edge skin silicon block 4;

[0068] The edge silicon block 4 is cut for the fourth time to obtain a silicon wafer, and the cutting surface of the fourth cutting is deflected by an angle θ3 relative to the (100) crystal plane 11 of the single crystal silicon rod 1, and θ3 satisfies 0°<θ3<90° and θ3≠45°.

[0069] Specifically, Figure 2 As shown, the first cutting of the single crystal silicon rod 1 can obtain the central silicon block 3 and the edge skin 2. The surface formed by the central silicon block 3 and the edge skin 2 based on the first cutting is called the cutting surface of the first cutting. Figure 8-10 As shown, the arc top material 22 and two side ear materials 23 of the edge skin 2 are removed along the tangent line 6 of the third cutting, so that the edge skin 2 becomes a rectangular structure, that is, an edge skin silicon block 4 is obtained, so as to facilitate the subsequent preparation of silicon wafers; the four cut surfaces of the edge skin silicon block 4 are all deflected velvet surfaces 21, and the crystal plane index of the deflected velvet surface 21 of the edge skin 2 is (HK0).

[0070] The edge skin silicon block 4 is cut for the fourth time to obtain a silicon wafer. The deflection angle of the cutting surface of the fourth cut relative to the (100) crystal plane 11 of the single crystal silicon rod 1 is θ3, and θ3 satisfies 0°<θ3<90° and θ3≠45°, so that the surface of the obtained silicon wafer is a deflected texturing surface 21. After texturing the surface of the silicon wafer, an inclined pyramid structure can be obtained. In this embodiment, the edge skin 2 material is used to prepare a silicon wafer with a pyramid structure, which improves the utilization rate of raw materials and saves costs.

[0071] When the deflection angle θ3 = 0° and 90°, the cut surface of the silicon wafer is (100) crystal plane 11, and the alkali texturing is a positive pyramid; when θ3 = 45°, the cut surface of the silicon wafer is (110) crystal plane, and this texturing does not produce a pyramid, but only an edge face composed of two (111) faces. When the deflection angle θ3 satisfies the conditions of 0°<θ3<90° and θ3≠45°, an inclined pyramid structure can be obtained.

[0072] In at least one embodiment, Fig.10As shown, taking the edge skin 2 of 210×105 as an example, the middle single crystal silicon rod 1 is 210×210, and the four edge pieces need to ensure that the edge skin 2 with a width of 105 is cut out. Fig.10 The middle end surface is deflected in the clockwise direction by a deflection angle θ1, that is, from the solid line frame to the dotted line frame, to obtain a side skin 2 of 210×105, and the side skin 2 is cut out along the tangent line 6.

[0073] In some embodiments, the edge silicon block 4 is cut for the fourth time to obtain a silicon wafer, including: slicing the edge silicon block 4 parallel to the cutting plane of the first cutting to obtain a silicon wafer.

[0074] Specifically, in this embodiment, the cutting surface of the first cutting, that is, the cutting surface of the edge skin formed when the first cutting obtains the edge skin, and the cutting surface of the fourth cutting are parallel to the cutting surface of the first cutting, so that the silicon wafer has a rectangular structure and the thickness of the silicon wafer is consistent everywhere, which is convenient for making battery cells.

[0075] In some embodiments, the edge silicon block 4 is cut for the fourth time to obtain a silicon wafer, including: stacking and solidifying multiple edge silicon blocks 4 in sequence along a direction perpendicular to the cutting surface of the first cutting, cutting and truncating along the stacking direction to obtain a production silicon block 5, and slicing the production silicon block 5 perpendicular to the stacking direction to obtain a silicon wafer.

[0076] In this embodiment, the cutting surface of the first cutting is the surface of each edge silicon block 4 formed in the first cutting.

[0077] Specifically, after the edge skin 2 is cut, if the size does not meet the actual industrial production needs, multiple edge skin silicon blocks 4 with deflected velvet surfaces 21 can be stacked and solidified, and then sliced ​​to obtain production silicon wafers required by actual industrial production.

[0078] Specifically, Fig. 9 As shown, a plurality of edge silicon blocks 4 with deflected velvet surfaces 21 are ground on the cutting surfaces with a grinding wheel, and the cutting surfaces are stacked and cured using glue to obtain a production silicon block 5 coded as BP431AAAA000110. Diamond wire is used to cut and truncate along the stacking direction to obtain four finished silicon blocks, and the half-rods of the finished products are coded as BP431AAAA0001T0C, BP431AAAA0001T0D, BP431AAAA0001T0E and BP431AAAA0001T0F, respectively, to be used for slicing.

[0079] In this embodiment, the surface of the production silicon block 5 parallel to the cutting surface of the first cut and the surface perpendicular to the cutting surface of the first cut are both deflected textured surfaces 21. Therefore, by cutting the production silicon block 5 along a direction parallel to the cutting surface of the first cut or along a direction perpendicular to the cutting surface of the first cut, a silicon wafer with a deflected textured surface 21 can be obtained.

[0080] One or more embodiments of the present application further discloses a silicon wafer, wherein the surface of the silicon wafer having a pyramid structure is a (HK0) crystal plane having a deflection angle relative to the (100) crystal plane 11 of the single crystal silicon rod 1 .

[0081] Specifically, the crystal plane index is determined by determining the coordinates of the intersection of the plane and the three coordinate axes of the unit cell, taking the reciprocals of the intercepts on the three coordinate axes, eliminating fractions, and converting them into the smallest mutually prime integers H, K, and L. The crystal plane index is generally denoted as (HKL). The three numbers H, K, and L correspond to the directions of the three crystal axes a, b, and c, respectively. If a number in the index is "0", it means that the crystal plane is parallel to the corresponding crystal axis. The (HK0) crystal plane is parallel to the c-axis because the intersection of the (HK0) crystal plane and the c-axis is ∞ and the reciprocal is 0.

[0082] By adopting the above technical solution, such as Figure 3 As shown, for a silicon wafer having a pyramid structure, no matter how the actual (100) crystal plane 11 of the silicon wafer is deflected, the pyramid structure 41 formed by alkali texturing of the silicon wafer is always a regular pyramid with the center line perpendicular to the (100) crystal plane 11; Figure 4 As shown, the surface of the silicon wafer used to process the pyramid structure 41, or the (HK0) crystal plane of the main structure 42 below the pyramid structure 41 of the silicon wafer, has a deflection angle relative to the (100) crystal plane 11, resulting in a deflection angle of the pyramid structure 41 relative to the silicon wafer main structure 42, that is, the pyramid structure formed on the surface of the silicon wafer is actually a pyramid structure inclined relative to the processed surface of the silicon wafer, so the deflection of the velvet surface 21 of the silicon wafer causes the physical visual deflection of the pyramid structure 41. Therefore, the battery cell prepared using the silicon wafer with a pyramid structure can reduce the light reflectivity and have a better light absorption effect.

[0083] One or more embodiments of the present application also discloses a battery cell, including the above-mentioned silicon wafer.

[0084] By adopting the above technical solution, the surface of the silicon wafer has an inclined pyramid structure, so that the surface of the battery cell has a pyramid structure, and there is a deflection angle between the line connecting the vertex and the center of the bottom surface of the pyramid structure and the normal direction of the silicon wafer surface, and the deflection angle is 0°<deflection angle<90° and the deflection angle ≠45.

[0085] By adopting the above technical solution, the solar cell made of silicon wafers with a pyramid structure can reduce the light reflectivity and have a better light absorption effect. The solar cell can match the installation inclination requirements of solar cell modules at different latitudes or specific scenes (such as building exterior walls), without the need to adjust and set the corresponding inclination through the bracket, solving the problem of inconvenient design and installation of solar cell modules with a pyramid structure in areas with complex terrain. By adopting the above technical solution, the reflectivity of the solar cell is lower than that of a normal solar cell, that is, the light absorption effect is better.

[0086] When the cell is observed in the opposite direction of deflection, Fig.11 As shown, A is a normal cell, and B is the texturing deflection cell of this embodiment. It can be seen that the texturing deflection cell has a darker color, which proves that the reflectivity is smaller than that of the normal cell, that is, the light absorption effect is better.

[0087] One or more embodiments of the present application further discloses a solar cell assembly, including a backplane and the above-mentioned cell sheet.

[0088] In this embodiment, the solar cell module can match the installation inclination requirements of different latitudes or specific scenes (such as building exterior walls), and there is no need to adjust and set the corresponding inclination through the bracket, which solves the problem of inconvenient design and installation of solar cell modules with a pyramid structure in areas with complex terrain.

[0089] Specifically, through the reflectivity test, the direction of the solar cells with the pyramid structure having a deflection angle is sorted and adjusted to ensure the consistency of the deflection direction of the pyramid structure when preparing the solar cell module.

[0090] In this embodiment, the sorted cells are processed through a solar cell assembly process to obtain a solar cell assembly with a pyramid structure having a deflection angle. Deflection direction and angle markings are affixed to the outer frame. When installing the solar cell assembly, it can be installed facing the direction of sunlight according to the pyramid structure deflection direction markings.

[0091] In this embodiment, a solar cell module with a pyramid structure having a deflection angle of θ1 can be applicable to two scenarios and requirements of installation inclination angles, and the two installation inclination angles are complementary angles to each other; specifically, two solar cell modules with a pyramid structure having a deflection angle of θ1 are obtained, namely, a solar cell module with a deflection angle of θ11 and a solar cell module with a deflection angle of θ12, such as Fig.12 As shown, when θ11+θ12=90°, they are two opposite angles on the left and right. The solar cell module with a deflection angle of θ11 can be flipped 180 degrees vertically to be suitable for the solar cell module with a corresponding deflection angle of θ12. Therefore, the deflection direction identification of the solar cell module includes θ11 and θ12, which are complementary angles to each other, to meet two installation requirements.

[0092] Embodiment 1, a method for preparing a solar cell module, comprising the steps of:

[0093] (1) Single crystal silicon rods are pulled;

[0094] (2) cutting the longer single crystal silicon rod into shorter single crystal silicon rods 1 suitable for square cutting;

[0095] (3) Figure 1 and Figure 2 As shown, the (100) crystal plane 11 of the short single crystal silicon rod 1 is used as a reference, and the first cutting is performed after the

[001] crystal zone axis 13 is deflected by an angle θ1, and a central silicon block 3 and four side skins 2 extending in the same direction as the

[001] crystal zone axis 13 are cut out. The cutting surface of the central silicon block 3 is a deflected textured surface 21, and the cutting surface of the side skin 2 is a deflected textured surface 21;

[0096] (4) Figure 7 As shown, the two opposite end faces of the central silicon block 3 that have not been cut are used as references, and the second cutting is performed after deflecting the center silicon block 3 by an angle θ2 in the clockwise direction (i.e., along the Figure 8 The silicon block is sliced ​​parallel to the cutting direction of the second cutting to obtain a silicon wafer, the cutting surface of the silicon wafer is the deflection textured surface 21, and the deflection textured surface 21 of the silicon wafer is alkali textured to form a pyramid structure, thereby obtaining a silicon wafer with a pyramid structure;

[0097] (5) Figure 8 As shown, the top material 22 and two side ear materials 23 of the edge skin 2 are cut and removed along the tangent line 6 of the third cutting to obtain the edge skin silicon block 4. The surface of the edge skin silicon block 4 where the top material 22 is removed and the surface opposite to it and where the side ear materials 23 are removed all have a deflected velvet surface 21, as shown in FIG. Fig. 9 As shown, a plurality of edge silicon blocks 4 are sequentially stacked and solidified along a direction perpendicular to the cutting surface of the first cutting, cut and truncated along the stacking direction to obtain a silicon block 5 for production, and the silicon block 5 for production is sliced ​​perpendicular to the stacking direction to obtain a silicon wafer, the cutting surface of the silicon wafer is a deflected textured surface 21, and the deflected textured surface 21 of the silicon wafer is alkali textured to form a pyramid structure, thereby obtaining a silicon wafer with a pyramid structure;

[0098] (6) The silicon wafer with the pyramid structure is subjected to a battery process such as coating to prepare a finished battery cell;

[0099] (7) The backplane, finished battery cells and other components are assembled into a solar cell module.

[0100] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims

1. A method for processing a silicon wafer, characterized in that: The following steps are involved: Performing a first cut on the single crystal silicon rod to obtain a central silicon block; The central silicon block is cut for a second time to obtain a silicon wafer, wherein the cutting surface of the second cutting is deflected at an angle of θ2 relative to the (100) crystal plane of the single crystal silicon rod, and θ2 satisfies 0°<θ2<90° and θ2≠45°; The surface of the silicon wafer is subjected to alkali texturing to form a pyramid structure, thereby obtaining a silicon wafer having a pyramid structure.

2. The method for processing a silicon wafer according to claim 1, wherein: The single crystal silicon rod is cut for the first time to obtain a central silicon block, comprising: cutting the single crystal silicon rod for the first time along a direction parallel to the [001] crystal band axis of the single crystal silicon rod, wherein the cutting surface of the first cut is deflected by an angle θ1 around the [001] crystal band axis relative to the (100) crystal plane of the single crystal silicon rod, and θ1 satisfies 0°<θ1<90° and θ1≠45°.

3. The method for processing a silicon wafer as claimed in claim 2, wherein: The central silicon block is cut for a second time to obtain silicon wafers, comprising: cutting the central silicon block along a cutting plane parallel to the first cutting to obtain silicon wafers.

4. The method for processing a silicon wafer according to claim 1, wherein: The central silicon block is cut for a second time to obtain a silicon wafer, comprising: cutting the central silicon block along a cutting plane intersecting with the [001] crystal band axis to obtain a silicon wafer.

5. The method for processing a silicon wafer as claimed in claim 2, wherein: Before the surface of the silicon wafer is subjected to alkali texturing to form a pyramid structure, the following steps are also included: Cutting the edge skin obtained after the first cutting for the third time to remove the arc top material and edge ear material of the edge skin to obtain the edge skin silicon block; The edge silicon block is cut for the fourth time to obtain a silicon wafer, and the cutting surface of the fourth cutting is deflected at an angle of θ3 relative to the (100) crystal plane of the single crystal silicon rod, and θ3 satisfies 0°<θ3<90° and θ3≠45°.

6. The method for processing a silicon wafer as claimed in claim 5, wherein: The edge silicon block is cut for the fourth time to obtain a silicon wafer, comprising: slicing the edge silicon block parallel to the cutting plane of the first cutting to obtain a silicon wafer.

7. The method for processing a silicon wafer as claimed in claim 5, wherein: The edge silicon block is cut for the fourth time to obtain silicon wafers, including: stacking and solidifying multiple edge silicon blocks in sequence along a direction perpendicular to the cutting surface of the first cutting, cutting and truncating along the stacking direction to obtain production silicon blocks, and slicing the production silicon blocks perpendicular to the stacking direction to obtain silicon wafers.

8. A silicon wafer, characterized in that: The surface of the silicon wafer having the pyramid structure is a (hk0) crystal plane having a deflection angle relative to the (100) crystal plane of the single crystal silicon rod.

9. A battery cell, characterized in that: Comprising the silicon wafer as claimed in claim 8.

10. A solar cell module, characterized in that: It comprises a back plate and the battery cell as claimed in claim 9.

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