A cutting method and system for improving appearance line mark degradation of solar cell pieces

Abstract

The application discloses a cutting method and system for improving appearance line mark degradation of a solar cell, comprising: determining initial, low-middle, and high-end feeding positions, setting initial, low-middle, and high-end cutting line speeds; setting low-middle and high-end cutting periods, and setting initial line mark width and target line mark width; cutting a single crystal silicon rod at the initial feeding position by using the initial cutting line speed to form a line mark pattern; judging whether the initial line mark width is reached, if yes, judging whether the low-middle feeding position is entered; if yes, cutting by using the low-middle cutting line speed and the low-middle cutting period, judging whether the target line mark width is reached, if yes, judging whether the high-end feeding position is entered; if yes, cutting by using the high-end cutting line speed and the high-end cutting period until the cutting is completed. The application can reduce the interference between line marks and fine grids, reduce the wave pattern of a cell product, and reduce the appearance line mark degradation proportion of a cell processing end.

Description

Technical Field

[0001] This invention relates to the field of silicon wafer cutting technology, and specifically to a cutting method and system for improving the appearance degradation of solar cell lines. Background Technology

[0002] As the substrate material for solar cell production, the quality of monocrystalline silicon wafers directly affects the conversion efficiency of the cells. Currently, most photovoltaic manufacturers use multi-wire cutting with steel wire to produce crystalline silicon wafers. This method involves cutting the entire monocrystalline silicon rod in one pass using the acceleration and deceleration motion of the steel wire, greatly increasing production capacity. However, wire cutting also introduces the problem of wire marks (wire marks: irregular marks left on the surface of the silicon wafer during the cutting of the monocrystalline silicon rod, including raised and recessed lines).

[0003] The existing cutting process produces a line mark width of approximately 1050 μm, while the existing screen printing process for solar cells produces a fine grid width of approximately 1120 μm and about 160 grids after sintering, with the grids parallel to the line mark. However, when the line mark width is too large in a certain area, the line mark will intersect with the fine grid, causing local slippage and collapse at the printing position. This leads to distortion of the aluminum paste printing lines, reducing the yield of the solar cell. At the same time, because the fine grid lines of the wafer are not obvious to the naked eye, after sintering, interference with the line mark produces moiré fringes, forming wave-like patterns that severely affect the appearance of the solar cell and further reduce its yield.

[0004] In summary, the existing silicon wafer cutting process and solar cell cutting process differ in line mark and grid width values ​​by only 70μm. Furthermore, due to the varying sizes of wire bows in the line marks, the overlap between the wire bows and the grid significantly generates lateral moiré patterns, resulting in severe wavy textures. This degrades the appearance of the solar cell through line mark defects, increases the defect rate, and severely impacts product quality and aesthetics. Therefore, there is an urgent need for a cutting process method that improves the appearance of solar cells by addressing the degradation caused by line mark defects. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a cutting method and system for improving the appearance degradation of solar cell lines. This method addresses the technical problem that existing silicon wafer cutting methods easily lead to the degradation of the appearance of the cell lines at the processing end, resulting in a high defect rate and significantly affecting product quality and aesthetics. The invention aims to reduce interference between the lines and the fine grid, alleviate the waviness of the finished cell, and reduce the proportion of degradation of the appearance of the cell lines at the processing end.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0007] A cutting method for improving the appearance degradation of solar cell lines includes the following steps:

[0008] Determine the initial feed position, low-to-medium feed position, and high-to-end feed position, and set the initial cutting line speed, low-to-medium cutting line speed, and high-to-end cutting line speed;

[0009] Set the low-to-medium cutting cycle, the high-to-end cutting cycle, and set the initial and target line widths;

[0010] At the initial feed position, using the initial cutting line speed, and with the good liquid carrying capacity of the steel wire, the single crystal silicon rod is cut to form line marks on the surface of the silicon wafer.

[0011] Determine whether the width of the line mark reaches the initial line mark width; if so, determine whether the steel wire has entered the low-to-medium feed position.

[0012] If so, then the low-medium cutting line speed and the low-medium cutting cycle are used for cutting, and it is determined whether the width of the line mark reaches the target line mark width. If so, it is determined whether the steel wire has entered the high-end feed position.

[0013] If so, the high-speed cutting line and the high-cycle cutting period are used for cutting until the silicon wafer is cut.

[0014] In a preferred embodiment of the present invention, setting the initial cutting line speed and the initial line width includes:

[0015] The initial cutting line speed is set to 2000-2200 m / min;

[0016] The initial line width is set to 2210 μm.

[0017] In a preferred embodiment of the present invention, determining the low-to-medium feed position, setting the low-to-medium cutting line speed, the low-to-medium cutting cycle, and the target line width includes:

[0018] Determine the low feed position and the medium feed position;

[0019] Set low and medium cutting line speeds;

[0020] Set low and medium cutting cycles;

[0021] Set the width of the first target line mark and the width of the second target line mark.

[0022] In a preferred embodiment of the present invention, when determining the low feed position and setting a low cutting line speed, a low cutting cycle, and a first target line width, the following are included:

[0023] The low feed position is defined as the cutting position ≤40mm.

[0024] The low cutting line speed is set to 2200-2400 m / min;

[0025] The low cutting cycle is set to a cycle of 1.25.

[0026] The width of the first target line mark is set to 1700 μm;

[0027] Specifically, when the width of the line mark is detected to reach the initial line mark width and the low feed position is entered, cutting is performed using the low cutting line speed and the low cutting cycle.

[0028] In a preferred embodiment of the present invention, determining the intermediate feed position and setting the intermediate cutting speed, intermediate cutting cycle, and second target line width includes:

[0029] The cutting position is defined as the intermediate feed position between 40-140mm.

[0030] The cutting speed is set to 2200-2400 m / min.

[0031] The cutting cycle is set to a period of 1.05-1.23.

[0032] Maintain the width of the second target line mark at 1700 μm;

[0033] Specifically, when the width of the line mark is detected to reach the first target line mark width and the feed position is reached, the cutting is performed using the medium cutting line speed and the medium cutting cycle.

[0034] In a preferred embodiment of the present invention, determining the final feed position, setting the final cutting speed, and the final cutting cycle includes:

[0035] Determine the high feed position and the last feed position;

[0036] Set the high cutting line speed and the final cutting line speed;

[0037] Set the high cutting cycle and the final cutting cycle;

[0038] The cutting method further includes setting the width of the third target line mark.

[0039] In a preferred embodiment of the present invention, when determining the high feed position and setting the high cutting line speed, high cutting cycle, and third target line width, the following are included:

[0040] The high feed position is defined as the cutting position ≥140mm.

[0041] The high cutting line speed is set to 2200-2400 m / min;

[0042] The high cutting cycle is set to a cycle of 0.9.

[0043] The width of the third target line mark is set to 2000 μm;

[0044] When the width of the line mark is detected to reach the second target line mark width and the high feed position is entered, cutting is performed using the high cutting line speed and the high cutting cycle.

[0045] In a preferred embodiment of the present invention, determining the final feed position and setting the final cutting line speed and final cutting cycle includes:

[0046] The final feed position is defined as the cutting position ≥188mm.

[0047] The final cutting line speed is set to ≤2000m / min;

[0048] The final cutting cycle is set to a cycle of 0.7.

[0049] When the width of the line mark is detected to reach the third target line mark width and the feed position is reached, cutting is performed using the final cutting line speed and the final cutting cycle.

[0050] In a preferred embodiment of the present invention, determining whether the width of the line mark reaches the initial line mark width and the target line mark width includes:

[0051] Based on the descent distance and number of cycles of the single-crystal silicon rod, the initial trace width and the target trace width are obtained, as shown in Formula 1:

[0052] X = G / Z (1);

[0053] In the formula, X is the initial line mark width or the target line mark width, G is the descent distance of the single crystal silicon rod, and Z is the number of cycles.

[0054] A cutting system for improving the appearance degradation of solar cell line marks, comprising:

[0055] First cutting parameter setting unit: used to determine the initial feed position, low-to-medium feed position and high-to-end feed position, and to set the initial cutting line speed, low-to-medium cutting line speed and high-to-end cutting line speed;

[0056] The second cutting parameter setting unit is used to set the low-to-medium cutting cycle, the high-to-end cutting cycle, the initial line mark width, and the target line mark width.

[0057] First cutting unit: used to cut the single crystal silicon rod at the initial feed position using the initial cutting line speed and with good liquid carrying capacity of the steel wire, forming line marks on the silicon wafer surface; to determine whether the width of the line marks reaches the initial line mark width, and if so, to determine whether the steel wire has entered the low-to-medium feed position;

[0058] The second cutting unit is used to cut the wire at the low-to-medium cutting speed and the low-to-medium cutting cycle when it enters the low-to-medium feed position. It determines whether the width of the wire mark reaches the target wire mark width. If so, it determines whether the wire has entered the high-to-low feed position.

[0059] The third cutting unit is used to cut the silicon wafer by using the high-end cutting line speed and the high-end cutting cycle when it enters the high-end feed position, until the cutting of the silicon wafer is completed.

[0060] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0061] (1) This invention increases the width of the line marks and reduces the number of line marks on the silicon wafer by designing and developing a new process cutting cycle, so as to reduce the interference between the line marks and the fine grid, reduce the wavy pattern of the finished cell, and reduce the appearance line mark degradation ratio at the processing end of the cell.

[0062] (2) The present invention sets different cutting line speeds, cutting cycles and feed widths at different feed positions, and cuts with corresponding cutting line speeds and cutting cycles after reaching the corresponding feed width and entering the corresponding feed position, thereby minimizing the number of line marks intersecting with the fine grid and reducing the influence of parallel or transverse moiré stripe phenomena.

[0063] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0064] Figure 1 This is a step diagram of the cutting method for improving the appearance degradation of solar cell lines provided by the present invention;

[0065] Figure 2 This is a comparison diagram of the wavy texture of the finished battery cells before and after the improvement provided in the embodiments of the present invention. Detailed Implementation

[0066] The cutting method provided by this invention for improving the appearance degradation of solar cell line marks, such as... Figure 1 As shown, it includes the following steps:

[0067] Step S1: Determine the initial feed position, low-to-medium feed position, and high-to-end feed position, and set the initial cutting line speed, low-to-medium cutting line speed, and high-to-end cutting line speed;

[0068] Step S2: Set the low-to-medium cutting cycle, the high-to-low cutting cycle, and set the initial line mark width and the target line mark width;

[0069] Step S3: At the initial feed position, using the initial cutting line speed and with the good liquid carrying capacity of the steel wire, the single crystal silicon rod is cut to form line marks on the surface of the silicon wafer.

[0070] Step S4: Determine whether the width of the wire mark has reached the initial wire mark width. If so, determine whether the steel wire has entered the low-to-medium feed position.

[0071] Step S5: If yes, then use low-medium cutting speed and low-medium cutting cycle for cutting, and determine whether the width of the line mark reaches the target line mark width. If yes, then determine whether the steel wire has entered the high-end feed position.

[0072] Step S6: If so, use high final cutting line speed and high final cutting cycle for cutting until the silicon wafer cutting is completed.

[0073] In steps S1 and S2 above, setting the initial cutting line speed and initial line width includes:

[0074] Set the initial cutting speed to 2000-2200 m / min;

[0075] Set the initial line width to 2210μm.

[0076] In steps S1 and S2 above, determining the low-to-medium feed position, setting the low-to-medium cutting line speed, low-to-medium cutting cycle, and target line width includes:

[0077] Determine the low feed position and the medium feed position;

[0078] Set low and medium cutting line speeds;

[0079] Set low and medium cutting cycles;

[0080] Set the width of the first target line mark and the width of the second target line mark.

[0081] Furthermore, when determining the low feed position and setting the low cutting line speed, low cutting cycle, and first target line width, the following are included:

[0082] A cutting position ≤40mm is defined as a low feed position;

[0083] Set the low cutting speed to 2200-2400 m / min;

[0084] Set the low cutting cycle to 1.25 cycles;

[0085] Set the width of the first target line mark to 1700μm;

[0086] Specifically, when the width of the line mark is detected to have reached the initial line mark width and the feed position is entered, a low cutting speed and a low cutting cycle are used for cutting.

[0087] Furthermore, when determining the feed position and setting the cutting speed, cutting cycle, and second target mark width, the following are included:

[0088] The cutting position between 40-140mm is defined as the medium feed position;

[0089] Set the cutting speed to 2200-2400 m / min;

[0090] Set the cutting cycle to 1.05-1.23.

[0091] The width of the second target line mark is kept at 1700 μm;

[0092] Specifically, when the width of the detected line mark reaches the first target line mark width and the feed position is reached, cutting is performed using a medium cutting speed and a medium cutting cycle.

[0093] In steps S1 and S2 above, determining the final feed position, setting the final cutting speed, and the final cutting cycle includes:

[0094] Determine the high feed position and the last feed position;

[0095] Set the high cutting line speed and the final cutting line speed;

[0096] Set the high cutting cycle and the final cutting cycle;

[0097] The cutting method also includes setting the width of the third target line mark.

[0098] Furthermore, when determining the high feed position and setting the high cutting line speed, high cutting cycle, and third target line width, the following are included:

[0099] A cutting position ≥140mm is defined as a high feed position;

[0100] Set the high cutting speed to 2200-2400 m / min;

[0101] Set the high cutting cycle to a cycle of 0.9;

[0102] Set the width of the third target line mark to 2000 μm;

[0103] When the width of the line mark is detected to reach the second target line mark width and the high feed position is entered, high cutting speed and high cutting cycle are used for cutting.

[0104] Furthermore, when determining the final feed position and setting the final cutting line speed and final cutting cycle, the following are included:

[0105] The position ≥188mm is defined as the final feed position;

[0106] Set the final cutting line speed to ≤2000m / min;

[0107] Set the final cutting cycle to 0.7 cycles;

[0108] When the width of the detected line mark reaches the third target line mark width and the feed position is reached, cutting is performed using the final cutting line speed and the final cutting cycle.

[0109] Furthermore, when determining whether the width of the line mark reaches the initial line mark width and the target line mark width, the following steps are taken:

[0110] Based on the descent distance and number of cycles of the single-crystal silicon rod, the initial trace width and target trace width are obtained, as shown in Formula 1:

[0111] X = G / Z(1);

[0112] In the formula, X is the initial line mark width or the target line mark width, G is the descent distance of the single crystal silicon rod, and Z is the number of cycles.

[0113] The cutting system provided by the present invention for improving the appearance degradation of solar cell lines includes: a first cutting parameter setting unit, a second cutting parameter setting unit, a first cutting unit, a second cutting unit, and a third cutting unit.

[0114] The first cutting parameter setting unit is used to determine the initial feed position, low-to-medium feed position, and high-to-end feed position, and to set the initial cutting line speed, low-to-medium cutting line speed, and high-to-end cutting line speed.

[0115] The second cutting parameter setting unit is used to set the low-to-medium cutting cycle, the high-to-end cutting cycle, and the initial and target line widths.

[0116] The first cutting unit is used to cut the single crystal silicon rod at the initial feed position with the initial cutting line speed and the good liquid carrying capacity of the steel wire, forming line marks on the surface of the silicon wafer; it determines whether the width of the line marks reaches the initial line mark width, and if so, it determines whether the steel wire has entered the low-to-medium feed position.

[0117] The second cutting unit is used to cut at a low-to-medium cutting speed and cycle when entering the low-to-medium feed position. It determines whether the width of the wire mark reaches the target wire mark width. If so, it determines whether the steel wire has entered the high-to-low feed position.

[0118] The third cutting unit is used to cut the silicon wafer by using the highest cutting speed and highest cutting cycle when it enters the highest feed position, until the cutting of the silicon wafer is completed.

[0119] The following embodiments are further illustrations of the present invention, but the scope of the present invention is not limited thereto.

[0120] This embodiment provides a cutting process method that can reduce the degradation rate of appearance lines after screen printing at the battery cell processing end. The method starts with the moiré fringe phenomenon, which is a periodic structure formed by the superposition of two sets of parallel fringes with similar periods. Taking a grating as an example, with two amplitude gratings G1 and G2, and periods T1 = T2 = T, assuming the grating lines of G1 are parallel to the Y-axis, and G2 intersects G1 at a small angle θ, then the angle α between the moiré fringe and the X-axis is α = -θ / 2. When T2 (or T1) has a small increment, becoming T'2, then angle α satisfies:

[0121] Tanα=(cosθ-T'2 / T1) / sinθ

[0122] As shown in the above formula, if the period of the grating changes, the direction of the moiré fringes will also change. Extending this principle to the silicon wafer end of a solar cell, parallel lines can form parallel moiré fringes with the fine grid. Simultaneously, the lines have a bow, and at the bow position, a certain angle is formed with the fine grid, creating transverse moiré fringes. When changes in external physical quantities cause changes in the period of the lines or fine grid, the direction of the moiré fringes also changes accordingly. Naturally, changes in linewidth not only alter the direction of the moiré fringes but also, approximating periodic changes, can mitigate the wavy pattern phenomenon. That is, under optimal conditions, printing the fine grid perpendicular to the lines can minimize the wavy pattern on the surface of the solar cell. However, not all solar cell processing ends will have the fine grid printed perpendicular to the lines. Therefore, this embodiment mainly designs and develops new process cutting cycles to increase the width of the lines and reduce the number of lines on the silicon wafer, thereby reducing interference between the lines and the fine grid, mitigating the wavy pattern of the finished solar cell, and reducing the degradation rate of the appearance lines at the processing end of the solar cell.

[0123] The technical solution of this embodiment uses a high cutting line speed (2000-2200 m / min) at the initial feed position. With good liquid carrying capacity of the steel wire, the line mark width reaches 2210 μm (line mark width = silicon rod descent distance / number of cycles). When entering the low feed position (cutting position ≤ 40 mm), a high cutting line speed (2200-2400 m / min) and a cycle of 1.25 (cutting cycle: feed + return, 1.25 cycles means 1.25 cycles in 1 minute) are used for cutting, and the line mark width reaches 1700 μm (line mark width = silicon rod descent distance / number of cycles), which is 1 / 3 of the fine grid width. At a feed rate of 0.5 times or more; in the medium feed position (cutting position at 40-140mm), using a high cutting line speed (2200-2400m / min) and a cycle of 1.05-1.23, the cutting line speed can be appropriately increased to increase the cutting force, but the cutting line speed is still at 2200-2400m / min), and the line width can still be maintained at 1700μm; in the high feed position (cutting position ≥140mm), using a high cutting line speed (2200-2400m / min) and a cycle of 0.9, the line width can be maintained above 2000μm; at the end of the cutting process (cutting position ≥188mm), using a lower cutting line speed (line speed ≤2000m / min) and a cycle of 0.7, the line width is still not consistent with the fine grid width, making them easily overlap. Once the cutting is complete, the width of the line marks on the overall silicon wafer surface can reach more than 1.5 times the width of the fine grid printed by screen printing.

[0124] In existing technologies, the width of the line marks is between 1400μm and 1500μm at different feed positions, which is about 1.3 times the width of the fine grid in screen printing. At the end of the cutting process, the width of the multiple line marks can completely overlap with the width of the fine grid, resulting in a large number of intersections between the line marks and the fine grid. Due to the transverse moiré stripe phenomenon, there are more wavy patterns on the fine grid, and the line mark degradation rate reaches 0.07% at the cell processing end.

[0125] In comparison, the cutting texture width of the technical solution in this embodiment can reach a maximum of 2260μm, which is twice the width of the fine grid in the screen printing process. Correspondingly, when the wire marks overlap with the fine grid, the wire mark period is approximately twice the fine grid period. It is easy to see that this embodiment uses a high wire speed and a high wire cutting cycle in combination from low feed to high feed positions. The width of the wire marks on the silicon wafer after cutting can be basically maintained at a minimum of 1700μm and 1.5 times or more the width of the fine grid. Even at the end of the cutting process, the multiple wire mark width can still be offset from the fine grid by 1120μm, minimizing the intersection of the wire marks with the fine grid, thereby reducing the impact of parallel or transverse moiré stripe phenomena. This greatly reduces the amount of degradation caused by the wavy lines in the finished battery. The improved wire mark degradation ratio is reduced to 0.02%, showing a significant improvement effect. Figure 2 As shown.

[0126] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A cutting method for improving the appearance degradation of solar cell lines, characterized in that, Includes the following steps: Determine the initial feed position, low-to-medium feed position, and high-to-end feed position, and set the initial cutting line speed, low-to-medium cutting line speed, and high-to-end cutting line speed; Set the low-to-medium cutting cycle, the high-to-end cutting cycle, and set the initial and target line widths; At the initial feed position, using the initial cutting line speed, and with the good liquid carrying capacity of the steel wire, the single crystal silicon rod is cut to form line marks on the surface of the silicon wafer. Determine whether the width of the line mark reaches the initial line mark width; if so, determine whether the steel wire has entered the low-to-medium feed position. If so, then the low-medium cutting line speed and the low-medium cutting cycle are used for cutting, and it is determined whether the width of the line mark reaches the target line mark width. If so, it is determined whether the steel wire has entered the high-end feed position. If so, the high-speed cutting line and the high-cycle cutting line are used for cutting until the silicon wafer is cut. When setting the initial cutting speed and initial mark width, the following are included: The initial cutting speed is set to 2000-2200 m / min; the initial line width is set to 2210 µm. When determining the low-to-medium feed position, setting the low-to-medium cutting speed, low-to-medium cutting cycle, and target mark width, the following should be included: Determine the low feed position and medium feed position; set the low cutting line speed and medium cutting line speed; set the low cutting cycle and medium cutting cycle; set the first target line mark width and the second target line mark width; When determining the low feed position and setting the low cutting line speed, low cutting cycle, and first target line width, the following are included: The low feed position is defined as the cutting position ≤ 40mm; the low cutting line speed is set to 2200-2400m / min; the low cutting cycle is set to 1.25 cycles; and the width of the first target line mark is set to 1700µm. When determining the feed position and setting the cutting speed, cutting cycle, and second target mark width, the following are included: The cutting position is defined as the intermediate feed position at 40-140mm; the intermediate cutting line speed is set to 2200-2400m / min; the intermediate cutting cycle is set to 1.05-1.23 cycles; and the width of the second target line mark is maintained at 1700µm. When determining the final feed position, setting the final cutting speed, and the final cutting cycle, the following should be included: The high feed position and the final feed position are determined; the high cutting line speed and the final cutting line speed are set; the high cutting cycle and the final cutting cycle are set; wherein, the cutting method further includes: setting the width of the third target line mark; When determining the high feed position and setting the high cutting line speed, high cutting cycle, and third target line width, the following are included: The high feed position is defined as the cutting position ≥140mm; the high cutting line speed is set to 2200-2400m / min; the high cutting cycle is set to a cycle of 0.9; and the width of the third target line mark is set to 2000µm. When determining the final feed position and setting the final cutting line speed and final cutting cycle, the following are included: The final feed position is defined as a cutting position ≥188mm; the final cutting line speed is set to ≤2000m / min; and the final cutting cycle is set to a cycle of 0.

7.

2. The cutting method for improving the appearance degradation of solar cell lines according to claim 1, characterized in that: When the width of the line mark is detected to reach the initial line mark width and the low feed position is entered, cutting is performed using the low cutting line speed and the low cutting cycle.

3. The cutting method for improving the appearance degradation of solar cell lines according to claim 1, characterized in that: When the width of the line mark is detected to reach the first target line mark width and the feed position is reached, the cutting is performed using the medium cutting line speed and the medium cutting cycle.

4. The cutting method for improving the appearance degradation of solar cell lines according to claim 1, characterized in that: When the width of the line mark is detected to reach the second target line mark width and the high feed position is entered, cutting is performed using the high cutting line speed and the high cutting cycle.

5. The cutting method for improving the appearance degradation of solar cell lines according to claim 1, characterized in that: When the width of the line mark is detected to reach the third target line mark width and the feed position is reached, cutting is performed using the final cutting line speed and the final cutting cycle.

6. The cutting method for improving the appearance degradation of solar cell lines according to any one of claims 1-5, characterized in that, When determining whether the width of the line mark reaches the initial line mark width and the target line mark width, the following steps are included: Based on the descent distance and number of cycles of the single-crystal silicon rod, the initial trace width and the target trace width are obtained, as shown in formula (1): （1）； In the formula, The initial line mark width or the target line mark width. The distance the single-crystal silicon rod descends is [missing information]. The number of cycles is denoted as .

7. A cutting system for improving the appearance degradation of solar cell lines, characterized in that, The system is applied to the cutting method for improving the appearance degradation of solar cell line marks as described in any one of claims 1 to 6, the system comprising: First cutting parameter setting unit: used to determine the initial feed position, low-to-medium feed position and high-to-end feed position, and to set the initial cutting line speed, low-to-medium cutting line speed and high-to-end cutting line speed; The second cutting parameter setting unit is used to set the low-to-medium cutting cycle, the high-to-end cutting cycle, the initial line mark width, and the target line mark width. First cutting unit: used to cut the single crystal silicon rod at the initial feed position, using the initial cutting line speed, and with the good liquid carrying capacity of the steel wire, to form line marks on the surface of the silicon wafer; Determine whether the width of the line mark reaches the initial line mark width; if so, determine whether the steel wire has entered the low-to-medium feed position. The second cutting unit is used to cut the wire at the low-to-medium cutting speed and the low-to-medium cutting cycle when it enters the low-to-medium feed position. It determines whether the width of the wire mark reaches the target wire mark width. If so, it determines whether the wire has entered the high-to-low feed position. The third cutting unit is used to cut the silicon wafer by using the high-end cutting line speed and the high-end cutting cycle when it enters the high-end feed position, until the cutting of the silicon wafer is completed.

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