Silicon wafer, battery piece, photovoltaic module and photovoltaic power generation system

Abstract

The utility model discloses a silicon wafer, a battery piece, a photovoltaic assembly and a photovoltaic power generation system, the silicon wafer comprises a body, the body is provided with a defect area, and the orthographic projection of the defect area along the thickness direction of the body is in a non-circular ring shape. According to the silicon wafer provided by the utility model, the surface of the silicon wafer has no concentric circles, thereby effectively improving the production efficiency of the silicon wafer and reducing the production cost of the silicon wafer.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic energy technology, and in particular to a silicon wafer, a solar cell, a photovoltaic module, and a photovoltaic power generation system. Background Technology

[0002] In related technologies, during the silicon wafer crystal growth process, ring-shaped marks or uneven regions may form radially on the silicon wafer, resembling concentric circles, a phenomenon known as the concentric circle anomaly. This anomaly reduces the silicon wafer's lifespan, thus affecting the efficiency of solar cells. Silicon wafers cut using crystals exhibiting this concentric circle anomaly will also show this anomaly on their surface. The occurrence of this anomaly leads to the downgrading or rejection of the manufactured silicon wafers, thereby reducing production efficiency and increasing production costs. Utility Model Content

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one objective of the present invention is to provide a silicon wafer with no concentric circles on its surface, which effectively improves the production efficiency and reduces the production cost of silicon wafers.

[0004] Another objective of this invention is to provide a battery cell using the aforementioned silicon wafer.

[0005] Another objective of this invention is to provide a photovoltaic module using the aforementioned silicon wafer.

[0006] The fourth objective of this invention is to provide a photovoltaic power generation system using the aforementioned silicon wafer.

[0007] A silicon wafer according to a first aspect of the present invention includes: a body having a defect region, wherein the orthographic projection shape of the defect region along the thickness direction of the body is non-circular.

[0008] According to the silicon wafer of this utility model embodiment, this solution changes the conventional silicon wafer cutting and processing method based on the oxygen content distribution trend of silicon rods and the concentric circle formation mechanism, effectively avoiding the formation of concentric circles in silicon wafers, producing silicon wafers without concentric circles, effectively improving the production efficiency of silicon wafers, reducing the product rejection rate and defect rate, reducing the production cost of silicon wafers, and making it more conducive to mass production and application.

[0009] According to some embodiments of the present invention, the orthographic projection shape of the defective region along the thickness direction of the body includes a straight line, an arc, or a dot.

[0010] According to some embodiments of the present invention, the body has two first sides and two second sides, the two first sides are opposite to each other, the second sides are located between the two first sides, and the two second sides are respectively connected to the two ends of the first side in the length direction. When the orthographic projection shape of the defect area along the thickness direction of the body includes a straight line or an arc, the arc extends along the first side.

[0011] According to some embodiments of the present invention, the oxygen content of the body gradually increases or decreases along the extension direction of the first side; and / or, the resistivity of the body gradually increases or decreases along the extension direction of the first side; and / or, the minority carriers of the body gradually increase or decrease along the extension direction of the first side.

[0012] According to some embodiments of the present invention, the silicon wafer is a rectangular silicon wafer; and / or, the size of the first side is 156mm~250mm; the size of the second side is 52mm~125mm; or; the size of the first side is 156mm~250mm; the size of the second side is 156mm~250mm.

[0013] According to some embodiments of the present invention, the silicon wafer is a P-type monocrystalline silicon wafer or an N-type monocrystalline silicon wafer.

[0014] According to some embodiments of the present invention, the first side is adapted to extend along the axial direction of the silicon rod.

[0015] The battery cell according to a second aspect of the present invention includes the silicon wafer described in the first aspect of the present invention.

[0016] A photovoltaic module according to a third aspect of the present invention includes a silicon wafer as described in the first aspect of the present invention, or a solar cell as described in the second aspect of the present invention.

[0017] A photovoltaic power generation system according to a fourth aspect of the present invention includes a silicon wafer as described in the first aspect of the present invention, a battery cell as described in the second aspect of the present invention, or a photovoltaic module as described in the third aspect of the present invention.

[0018] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0020] Figure 1This is a schematic diagram showing the arc shape of the orthographic projection of the defect region of the silicon wafer along the thickness direction of the body according to an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of a silicon wafer according to an embodiment of the present invention.

[0022] Figure label:

[0023] 100. Silicon wafers;

[0024] 1. Main body; 11. First side; 12. Second side;

[0025] 2. Defect area; 21. Arc-shaped; 22. Straight line. Detailed Implementation

[0026] The embodiments of this utility model are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Figures 1-2 A silicon wafer 100 according to a first aspect embodiment of the present invention is described.

[0027] According to a first aspect of the present invention, a silicon wafer 100 includes a body 1.

[0028] Specifically, the body 1 has a defect region 2, and the orthographic projection shape of the defect region 2 along the thickness direction of the body 1 is non-circular. For example, in Figure 1 In the example, the thickness direction of the body 1 is perpendicular to the surface of the body 1. The defect region 2 on the surface of the silicon wafer 100 is non-circular, that is, the silicon wafer 100 is a silicon wafer 100 without concentric circles.

[0029] For example, N-type single-crystal silicon wafers are prepared by heating high-purity silicon material with oxygen doped with oxygen atoms under specific conditions. During this process, oxygen atoms penetrate deep into the silicon lattice in a unique way. Due to the relatively large size of oxygen atoms, a series of diffusion and structural changes occur after they enter the lattice. Specifically, oxygen atoms form chemical bonds with silicon atoms, and as the temperature rises, the oxygen atoms gradually diffuse deeper into the crystal. However, because the diffusion process is very slow, the oxygen atoms form a series of ring structures with varying densities within the crystal. These ring structures are typically the concentric circles mentioned above. Each concentric circle represents a different oxygen atom concentration region, and the radius of these concentric circles represents the distance the oxygen atoms diffuse from the surface to the interior.

[0030] In traditional technology, the common method for cutting silicon wafers is to first cut a silicon rod into round bars, then remove the edges along the axial direction of the rod to obtain a cuboid shape, and finally cut it radially into silicon wafers. The oxygen content distribution on the surface of the silicon rod is as follows: the oxygen content first decreases and then increases along the axial direction, while the oxygen content first increases and then decreases radially.

[0031] Based on the aforementioned oxygen content distribution, this application obtains a rectangular silicon rod, which is then cut along its central axis to obtain a silicon wafer 100. By changing the traditional radial silicon wafer 100 cutting method, the formation of concentric circles is effectively avoided, resulting in a silicon wafer 100 without concentric circles, thereby reducing silicon wafer 100 loss. This cutting method effectively reduces the rate of low-grade or defective silicon wafers 100, thereby improving the production efficiency of silicon wafers 100 and reducing the production cost of silicon wafers 100.

[0032] According to the silicon wafer 100 of this utility model embodiment, this solution changes the conventional silicon rod cutting and processing method based on the oxygen content distribution trend of silicon rods and the concentric circle formation mechanism, effectively avoiding the formation of concentric circles in silicon wafer 100, producing silicon wafer 100 without concentric circles, effectively improving the production efficiency of silicon wafer 100, reducing the product rejection rate and defect rate, and also reducing the production cost of silicon wafer 100, which is more conducive to mass production and application.

[0033] According to some embodiments of this utility model, combined with Figure 1 and Figure 2 The orthographic projection shape of the defect region 2 along the thickness direction of the body 1 includes a straight line 22, an arc 21, or a dot (not shown in the figure).

[0034] Defects disrupt the periodic symmetry of a crystal, causing the actual crystal to deviate from the ideal crystal structure. Among various defects, they can be classified according to their dimensionality into point defects, line defects, and surface defects.

[0035] Crystal defects have a significant impact on crystal growth, mechanical properties, electrical properties, magnetic properties, and other aspects. For example, in this application, the conventional silicon wafer 100 cutting process was modified based on the oxygen content distribution trend of the silicon rod and the concentric circle formation mechanism, so that the resulting silicon wafer 100 no longer exhibits the concentric circle phenomenon, and the orthographic projection shape of the defect region 2 in the thickness direction of the silicon wafer 100 can be a straight line 22 (e.g., ...). Figure 2 As shown), arc 21 (as shown) Figure 1 (As shown) or dots. Furthermore, the aforementioned straight line 22, arc 21, or dot-shaped defects are more concentrated on the silicon wafer 100, which reduces wafer loss more effectively than concentric circles. Additionally, by cutting the wafer into half-wafers, the defects are concentrated on one half, eliminating the phenomenon on the other half, further reducing wafer loss and thus lowering costs.

[0036] According to some embodiments of this utility model, combined with Figure 1 and Figure 2The body 1 has two first sides 11 and two second sides 12. The two first sides 11 are opposite to each other, and the second sides 12 are located between the two first sides 11. The two second sides 12 are respectively connected to the two ends of the first side 11 in the length direction. When the orthographic projection shape of the defect region 2 along the thickness direction of the body 1 includes a straight line 22 or an arc 21, the arc 21 extends along the first side 11.

[0037] For example, in Figure 1 and Figure 2 In the example, the shaped silicon wafer 100 can be approximately rectangular or square. For example, Figure 1 The two sides in the left-right direction are the first side 11, and the two sides in the up-down direction are the second side 12. The connection between the first side 11 and the second side 12 is arc-shaped 21. When the orthographic projection shape of the defect region 2 along the thickness direction of the body 1 includes the arc 21, the arc 21 extends along the first side 11, that is, along... Figure 1 The defect extends vertically. In other words, defect region 2 is relatively concentrated, located only in one direction of silicon wafer 100. Furthermore, by cutting the wafer into half-wafers, defect region 2 can be concentrated on one half, and this defect will not appear on the other half, thereby effectively reducing the rate of low-grade or substandard products, improving the production efficiency of silicon wafer 100, and reducing production costs.

[0038] According to some embodiments of this utility model, the oxygen content of the body 1 gradually increases or decreases along the extending direction of the first side 11. And / or, the resistivity of the body gradually increases or decreases along the extending direction of the first side. And / or, the minority carriers of the body gradually increase or decrease along the extending direction of the first side.

[0039] For example, in Figure 2 In the example, the oxygen content on silicon wafer 100 gradually decreases from top to bottom along the direction of the arrow. The oxygen content of silicon wafer 100 has a significant impact on its performance. Specifically, the level of oxygen content affects key parameters of silicon wafer 100 such as conversion efficiency, electrical characteristics, purity, and minority carrier lifetime.

[0040] In the embodiments of this application, by changing the radial cutting method of the silicon wafer 100, the oxygen content of the silicon wafer 100 along the extension direction of the aforementioned straight line 22 or arc gradually increases or decreases, exhibiting a linear change trend. This configuration effectively reduces the formation of concentric silicon wafers 100, improves product quality, increases the utilization rate of silicon rods, and significantly reduces production costs.

[0041] According to some embodiments of the present invention, the resistivity of the body 1 gradually increases or decreases along the extending direction of the first side 11.

[0042] For example, in Figure 2In the example, the resistivity on silicon wafer 100 gradually decreases from top to bottom along the direction of the arrow. Resistivity uniformity is a critical issue during the growth of N-type high-resistivity silicon single crystals. During growth, due to the small segregation coefficient of phosphorus, radial resistivity uniformity is easily poor, resulting in a phenomenon where the resistivity is low in the center and high around the periphery, affecting the local electrical performance of the device.

[0043] This application obtains silicon wafer 100 by changing the radial cutting method of silicon wafer 100, so that the resistivity of silicon wafer 100 gradually decreases from top to bottom along the first side 11, showing a linear change trend, so that the resistivity distribution of silicon wafer 100 is uniform, thereby reducing the defect rate of products and avoiding the impact of excessively large area on the surface of silicon wafer 100 on the manufacturing of solar cells.

[0044] According to some embodiments of the present invention, the minority carriers of the body 1 gradually increase or decrease along the extending direction of the first side 11.

[0045] For example, in Figure 2 In the example, the minority carrier lifetime on silicon wafer 100 gradually decreases from top to bottom along the arrow. Minority carrier lifetime refers to the time that a minority of charge carriers (i.e., those with a lower concentration in a semiconductor) survive in the semiconductor material. In photovoltaic cells, a longer minority carrier lifetime means that charge carriers can participate more effectively in the charge separation process, thereby improving the cell's photoelectric conversion efficiency.

[0046] This application modifies the radial cutting method of the silicon wafer 100 to achieve a linear distribution of minority carrier lifetime along the extension direction of the first side 11. This results in the minority carrier lifetime of the silicon wafer 100 gradually decreasing from top to bottom in a linear fashion. This configuration avoids the concentration of defect regions 2, ensuring the quality of the silicon wafer 100 and thus improving its yield.

[0047] Furthermore, in the embodiments of this application, the oxygen content, resistivity, and minority carrier lifetime distribution trends of the silicon wafer 100 are consistent, all exhibiting a linear increasing or decreasing trend along the extension direction of the first side 11. This arrangement avoids the influence of oxygen content, resistivity, and minority carriers on the silicon wafer 100, thereby ensuring the power generation efficiency of subsequent solar cells and improving the utilization rate of the silicon wafer 100.

[0048] According to some embodiments of this utility model, combined with Figure 1 and Figure 2 The silicon wafer 100 is a rectangular silicon wafer 100. And / or, the size of the first side 11 is 156mm~250mm; the size of the second side 12 is 52mm~125mm. Or; the size of the first side 11 is 156mm~250mm; the size of the second side 12 is 156mm~250mm.

[0049] For example, combining Figure 1 and Figure 2 The silicon wafer 100 is rectangular in shape. In the cutting process, the rectangle makes the cutting process more efficient, reducing the width of the cutting channels compared to other shapes, decreasing material loss during cutting, and increasing the yield of silicon wafer 100. Moreover, the rectangular silicon wafer 100 has advantages in terms of large-size applications, reducing the number of silicon wafers 100 required per unit module while ensuring sufficient light-receiving area, thus improving production efficiency. Furthermore, the rectangular silicon wafer 100 increases the actual light-receiving area of ​​the module, allowing it to absorb more light energy, thereby improving photoelectric conversion efficiency and increasing the module's power generation. The regular shape of the rectangular silicon wafer 100 module makes it easier to arrange and fix during installation, improving installation efficiency and reducing installation difficulty, making it particularly suitable for large-scale photovoltaic power plant construction and distributed photovoltaic applications.

[0050] Specifically, the dimensions of the first side 11 and the second side 12 of the rectangular silicon wafer 100 can be varied within the aforementioned range according to actual conditions. For example, when the dimension of the first side 11 is less than 156mm, the cutting utilization rate of the silicon rod will be reduced, resulting in more cutting scrap. Moreover, if the dimension of the first side 11 is too short, the light-receiving area of ​​the silicon wafer 100 will be smaller, reducing the absorbed light energy and directly leading to a decrease in photoelectric conversion efficiency, which in turn reduces the power generation of the module. However, when the dimension of the first side 11 is greater than 250mm, the length of the first side 11 is too long, which will directly increase the difficulty of cutting and transporting the silicon wafer 100. Furthermore, when the dimension of the first side 11 is too long, under illumination conditions, the incident angle of light at the edge will differ significantly from that at the center, resulting in reduced light absorption and utilization efficiency at the edge and causing optical losses. In addition, large-area silicon wafers 100 are more prone to surface flatness differences, further affecting light absorption and reflection and reducing the overall photoelectric conversion efficiency. Therefore, when the size of the first side 11 of the rectangular silicon wafer 100 is within the above range, the size setting is reasonable, which facilitates the cutting and transportation of the silicon wafer 100, improves the utilization rate of the silicon rod, and enhances the photoelectric conversion efficiency.

[0051] When the size of the second side 12 is less than 52mm, it increases the difficulty of cutting the silicon wafer 100 and the rate of scrap generation. Furthermore, an excessively short second side 12 will result in lower power output per module, requiring more modules to install a photovoltaic power station of the same power, increasing installation workload and time costs, and potentially necessitating more installation accessories and support structures, further increasing installation costs. However, when the size of the second side 12 is greater than 250mm, it becomes too large, further impacting its cutting, transportation, and usage costs. Therefore, when the size of the second side 12 falls within the aforementioned two ranges, the size setting is reasonable, effectively improving its utilization rate and providing possibilities for the silicon wafer 100 to be applied to various specifications of photovoltaic equipment or installation scenarios. When the sizes of the first and second sides are the same, the silicon wafer 100 is square. In other words, the silicon wafer 100 can be a whole silicon wafer 100 or a small slice of various commonly used sizes. For example, the specification of a rectangular silicon wafer 100 can be 156.75mm. 156.75mm, 182.2mm 182.3mm, 182.2mm 191.6mm, 182.2mm 210mm and 210mm 210mm, etc. But not limited to these.

[0052] According to some embodiments of the present invention, the silicon wafer 100 is a P-type monocrystalline silicon wafer or an N-type monocrystalline silicon wafer.

[0053] P-type monocrystalline silicon wafers are semiconductor materials based on monocrystalline silicon, formed by doping with trivalent elements. P-type monocrystalline silicon wafers possess excellent electrical conductivity, primarily determined by the holes formed by the doped trivalent elements. Holes are positively charged charge carriers that can move under the influence of an electric field, thus forming an electric current. Furthermore, P-type monocrystalline silicon wafers have a high light absorption coefficient, effectively absorbing photon energy from sunlight to generate photogenerated charge carriers, thereby achieving photoelectric conversion. In addition, P-type monocrystalline silicon wafers have high mechanical strength and stability, capable of withstanding certain external forces and temperature changes, and are not easily deformed or broken. Simultaneously, monocrystalline silicon has high thermal conductivity, which facilitates heat dissipation during operation, ensuring the performance and stability of the device.

[0054] N-type single-crystal silicon wafers are semiconductor materials formed by doping intrinsic silicon crystals with pentavalent elements. N-type single-crystal silicon wafers are primarily conductive electronically. Due to the doping with pentavalent elements, there are relatively more free electrons as majority carriers, while holes are minority carriers. Furthermore, N-type single-crystal silicon wafers have a high light absorption coefficient, effectively absorbing photon energy from sunlight to generate photogenerated carriers, thus achieving photoelectric conversion. Like P-type single-crystal silicon wafers, N-type single-crystal silicon wafers also have a regular crystal structure with orderly atomic arrangement, resulting in high mechanical strength and stability. They can withstand certain external forces and temperature changes and are not easily deformed or broken. In addition, single-crystal silicon has high thermal conductivity, which is beneficial for heat dissipation during operation, ensuring the performance and stability of devices.

[0055] With this configuration, when silicon wafer 100 is a P-type or N-type monocrystalline silicon wafer, it possesses advantages such as good electrical conductivity, high light absorption efficiency, and high mechanical strength and stability, which are beneficial for its subsequent application development and enhance its application prospects in the photovoltaic field. Furthermore, it increases the possibilities for material selection for silicon wafer 100, making it suitable for various types of silicon wafers.

[0056] According to some embodiments of the present invention, the first side 11 is adapted to extend along the axial direction of the silicon rod.

[0057] For example, in Figure 1 In the example, the left and right sides are the first side 11. In this application, the silicon wafer 100 is cut along the central axis of the cylindrical silicon rod (not shown in the figure), that is, the first side 11 of the silicon wafer 100 is the side length along the central axis of the silicon rod. This effectively reduces the production of concentric silicon wafers and improves the production efficiency of the silicon wafer 100.

[0058] The battery cell (not shown) according to a second aspect embodiment of the present invention includes a silicon wafer 100 according to a first aspect embodiment.

[0059] According to some embodiments of the present invention, by using the silicon wafer 100 of the above embodiments, the conversion efficiency of the solar cell is improved and the performance of the solar cell is enhanced.

[0060] A photovoltaic module (not shown) according to a third aspect embodiment of the present invention includes a silicon wafer 100 according to a first aspect embodiment or a solar cell according to a second aspect embodiment.

[0061] According to some embodiments of this utility model, by using the silicon wafer 100 or battery cell of the above embodiments, the conversion efficiency of photovoltaic modules is effectively improved, the cracking phenomenon that may occur in the processing of photovoltaic modules is avoided, the yield of photovoltaic module products is guaranteed, and the power generation capacity of photovoltaic systems is improved.

[0062] A photovoltaic power generation system (not shown) according to a fourth aspect embodiment of the present invention includes a silicon wafer 100 according to a first aspect embodiment, a battery cell according to a second aspect embodiment, or a photovoltaic module according to a third aspect embodiment.

[0063] Improving the performance and production efficiency of silicon wafer 100 plays a crucial role in enhancing the performance of photovoltaic power generation systems. With this configuration, by employing the silicon wafer 100, solar cells, or photovoltaic modules described in the above embodiments, the photothermal conversion efficiency of the photovoltaic power generation system can be effectively improved, thus significantly enhancing its performance.

[0064] The silicon wafer 100, solar cell, photovoltaic module, and photovoltaic power generation system according to the embodiments of this utility model, as well as their operation, are known to those skilled in the art and will not be described in detail here.

[0065] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0066] In the description of this utility model, "multiple" means two or more.

[0067] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0068] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A silicon wafer, characterized in that, The silicon wafer comprises: The body has a defective region, and the orthographic projection shape of the defective region along the thickness direction of the body is non-circular.

2. The silicon wafer according to claim 1, characterized in that, The orthographic projection shape of the defective region along the thickness direction of the body includes a straight line, an arc, or a dot.

3. The silicon wafer according to claim 2, characterized in that, The body has two first sides and two second sides, the two first sides are opposite to each other, the second sides are located between the two first sides, and the two second sides are respectively connected to the two ends of the first side in the length direction. When the orthographic projection shape of the defect area along the thickness direction of the body includes a straight line or an arc, the arc extends along the first side.

4. The silicon wafer according to claim 3, characterized in that, Along the extension direction of the first side, the oxygen content of the body gradually increases or decreases; and / or, Along the extension direction of the first side, the resistivity of the body gradually increases or decreases; and / or; Along the extension direction of the first side, the minority carriers of the body gradually increase or decrease.

5. The silicon wafer according to claim 3, characterized in that, The silicon wafer is a rectangular silicon wafer; and / or, The dimensions of the first side are 156mm to 250mm; the dimensions of the second side are 52mm to 125mm; or; The dimensions of the first side are 156mm to 250mm; the dimensions of the second side are 156mm to 250mm.

6. The silicon wafer according to claim 3, characterized in that, The silicon wafer is a P-type monocrystalline silicon wafer or an N-type monocrystalline silicon wafer.

7. The silicon wafer according to claim 3, characterized in that, The first side is adapted to extend along the axial direction of the silicon rod.

8. A battery cell, characterized in that, Includes the silicon wafer according to any one of claims 1-7.

9. A photovoltaic module, characterized in that, It includes the silicon wafer according to any one of claims 1-7, or the solar cell according to claim 8.

10. A photovoltaic power generation system, characterized in that, It includes the silicon wafer according to any one of claims 1-7, the solar cell according to claim 8, or the photovoltaic module according to claim 9.

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