A method for cutting a solar cell sheet

Abstract

The present invention proposes a method for cutting solar cells, which mainly uses two laser beams to align the cell to be split line for cutting, and at the same time, a cooling unit sprays a cooling medium to the split line, so that the cell is cut under a smaller internal stress, and no deposits are formed at the split line. The equipment used in this method mainly includes: a fixing frame for installing various components; a cell transport unit for transporting solar cells so that the solar cells move along the split line path relative to the focus point of the first laser beam and the second laser beam; a laser assembly for generating the first laser beam and the second laser beam; and a cooling unit for spraying a cooling medium to the split line or split point of the cell.

Description

Technical Field

[0001] The present invention relates to a solar cell chip processing method, and in particular to a solar cell chip cutting method. The present invention also relates to a special cutting device used in the cutting method. Background Art

[0002] In recent years, the component industry has developed rapidly. Through continuous experiments and research, major component manufacturers have found that the "de-whitening" technology in particular can more effectively improve component efficiency, reduce the cost per kilowatt-hour, and increase benefits. Therefore, the research and development of the "de-whitening" technology has greatly promoted the development of high-efficiency component packaging technology in the photovoltaic industry and is unanimously favored by the industry.

[0003] Compared with the general conventional component technology, the "de-whitening" technology is also called splicing, merging, and stacking. It optimizes the component structure, that is, it increases the utilization rate of the component receiving light under the same area, improves the output power of the component, and ensures the minimum power loss during the component packaging process. Therefore, the "de-whitening" technology has become a hot topic for various component manufacturers and is also an inevitable trend for the development of the photovoltaic industry. The welding production line of the "de-whitening" component has become an urgently needed product for the current social development and is also an urgent need for various component manufacturers. Because the "de-whitening" technology for solar cells is used to cut the existing square solar cells into small pieces and then weld them in series, and the core technology is the cell segmentation technology. At present, the existing cell segmentation technology uses a laser to thermally ablate a cut on the surface of the cell, and then uses mechanical breaking to separate the solar cell. Using this method, due to the high temperature of laser ablation, some ablation deposits will be formed on the cut surface of the cell, which is difficult to clean. In addition, because ablation will form a heat-affected zone on the surface of the cell, the surface area of ​​the cell will be reduced, which will reduce the efficiency and power of the manufactured component and make it easy to crack. Therefore, it cannot meet the requirements of demanding specific component applications.

[0004] The publication number is: CN207952963U, and the name is: A laser scribing machine for solar cell monolithic wafer, which discloses a laser scribing machine, including: a laser generator mounted on an adapter and capable of adjusting the position, and a heat sink mounted at the bottom of the laser generator. Although this method directly uses laser to completely cut the cell sheet and does not require mechanical cracking, the use of a single beam laser cutting requires the laser power to be increased, which will cause significant damage to the cutting site. Summary of the invention

[0005] The present invention solves the technical problems existing in the prior art and provides a solar cell sheet cutting method and cutting equipment.

[0006] In order to reduce the damage to the cut section of the battery cell, the present invention uses two laser beams to cut the battery cell, and is assisted by a liquid cooling device, so that the battery cell can be sliced ​​with minimal damage.

[0007] Furthermore, the first laser beam and the second laser beam are simultaneously focused on the position to be split of the battery cell, wherein the first laser beam cuts a splitting line of a certain length on the surface of one end of the battery cell, and the splitting line is not sufficient to break the battery cell, and the second laser beam heats the battery cell along the splitting line of the battery cell and its extension line. While the above two laser beams act on the battery cell to be cut, a cooling medium is sprayed along the splitting line of the battery cell to be split, so as to form hot and cold temperature zones so that the compressive stress of the material below the splitting line and at the extension line of the splitting line is greater than the tensile stress, so that the battery cell breaks, wherein the line to be split refers to a trajectory line where a battery cell is completely broken.

[0008] Furthermore, in order to first cut a dividing line with a certain length on the surface of one end of the battery cell, the first laser beam can be selected as a pulsed laser beam to perform the action of marking the dividing line on the battery cell.

[0009] Furthermore, in order to quickly heat the cell splitting line, the second laser beam is a continuous thermal laser beam, which heats the cell splitting line and its extension line.

[0010] Furthermore, in order to unify the reference, the first laser beam, the second laser beam and the sprayed cooling medium are focused on the same starting point of the to-be-split line of the battery cell.

[0011] Furthermore, the dividing lines formed by the first laser beam on the surface of the cell are discontinuous or continuous dividing lines along the direction of the cell to be split.

[0012] Furthermore, in order to cut the battery cell in a pre-designed direction, during the process of the first laser beam, the second laser beam and the cooling medium acting on the battery cell, the first laser beam, the second laser beam and the cooling medium can move relative to the battery cell along the direction of the splitting line.

[0013] Furthermore, in order to cut the battery cell in a pre-designed direction, during the process of the first laser beam, the second laser beam and the cooling medium acting on the battery cell, the battery cell can also move along the direction of the splitting line relative to the first laser beam, the second laser beam and the cooling medium.

[0014] Furthermore, in order to make the two laser beams produce different effects on the battery cell, the distances between the first laser beam and the second laser beam reaching the battery cell and the surface of the battery cell are achieved by adjusting the height position of the battery cell.

[0015] The present invention also provides a cutting device for cutting solar cells, which is used to implement the above-mentioned solar cell cutting method, and the cutting device at least comprises: a fixing frame, which is used to receive and install components for transporting the solar cells and generating the first laser beam and the second laser beam respectively;

[0016] A cell sheet transmission unit installed on the fixing frame is used to transmit the solar cell sheet so that the solar cell sheet moves along the path of the to-be-split line relative to the focal points of the first laser beam and the second laser beam to achieve the splitting of the cell sheet;

[0017] A laser assembly mounted on the fixing frame and located above the cell transmission portion, for generating a first laser beam and a second laser beam;

[0018] The cooling part is installed on the fixing frame and located above the battery cell transmission part. When the two laser beams act on the battery cell to be cut, it is used to spray the cooling medium to the position of the battery cell's to-be-split line.

[0019] Further, in order to allow the solar cells to be cut by the laser beam in sequence, the structure of the solar cell transmission part at least includes: a receiving platform for receiving the solar cell;

[0020] A horizontal driving assembly installed on the base of the fixing frame is used to drive the receiving platform to realize reciprocating motion thereon, so that the plurality of battery sheets pass smoothly and sequentially through the lower ends of the focusing points of the first laser beam and the second laser beam;

[0021] A device for adjusting the vertical distance between the first laser beam reaching the inside of the battery cell and the surface of the battery cell.

[0022] Furthermore, in order to adjust the vertical distance between the laser beam reaching the inside of the cell and the surface of the cell, the device may be: a lifting drive assembly installed at the end of the horizontal drive assembly and the drive end is located at the bottom of the receiving platform.

[0023] Furthermore, in order to adjust the vertical distance between the laser beam reaching the inside of the cell and the surface of the cell, the device may also be a device for adjusting the position of the first laser beam generating component.

[0024] Furthermore, in order to realize cutting of the battery cell by two laser beams, the laser assembly includes: a first laser generating a first laser beam; and a second laser generating a second laser beam.

[0025] Furthermore, in order to adjust the angle and direction of the laser beam directed toward the solar cell, the laser assembly further comprises: a device for adjusting the angle and irradiation position of the laser beam generated by the first laser and the second laser.

[0026] Furthermore, in order to achieve rapid cooling of the battery cell after cutting, the cooling unit includes: a nozzle for spraying a cooling medium; and a device for adjusting the angle and position of the nozzle spraying the cooling medium.

[0027] The technical effect of the present invention is that: the present invention uses two laser beams with different energy densities to respectively perform scribing and heating actions on the parts of the same to-be-split line of the solar cell, the first laser beam scratches a split line with a certain length on the surface of the cell, the second laser beam heats along the split line and its extension line, and at the same time, the cooling device sprays the cooling medium on the to-be-split line to reduce the fracture stress of the cell material below the split line and its extension line, so that the compressive stress of the material is greater than the tensile stress, thereby breaking the cell; when the method of the present invention is used to cut and split the solar cell, the solar cell material is heated by the second laser beam and then heated. The expansion causes the pressure in the heated area to rise, and at the same time, the tensile stress around the heated area also increases. The cooling medium, such as deionized water, sprayed at the line to be split will form a cooling zone in the area, thereby causing tangential tensile stress. Under the superposition of the two stresses, the fracture stress of the material in the area is significantly reduced. The tensile stress generated will cause the battery cell material to crack below the dividing line formed by the first laser beam and at the extension line of the horizontal plane, thereby completely splitting the battery cell. Compared with the traditional battery cell splitting technology, the cutting method of the present invention has a fast separation speed, a very smooth fracture surface, and no fragmentation or microcracks in the battery cell.

[0028] The cutting equipment using the above cutting method mainly includes: a transmission part for moving the battery sheet along the cutting line direction, a laser component for generating a first laser beam and a second laser beam, and a cooling part for spraying a cooling medium.

[0029] The first laser beam, the second laser beam and the sprayed cooling medium are focused on the same starting point of the to-be-split line of the cell sheet, so that the positions of the first laser, the second laser and the cooling unit are adjusted according to the same reference point, making the entire cutting device more compact.

[0030] The transmission part can not only move a single cell along the cutting direction, but also make multiple cells pass smoothly through the lower end of the focusing point of the first laser beam and the second laser beam in sequence;

[0031] The laser assembly and the cooling unit can not only be fixed on the fixing frame, but also can actively move back and forth relative to the battery sheet along the direction of the line to be split. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of a method for cutting a solar cell sheet in the present invention;

[0033] Figure 2 is an axonometric view of the cutting device of the present invention;

[0034] Figure 3 is an axonometric diagram of the installation position of the first laser in the present invention;

[0035] Figure 4 is an axonometric diagram of the installation position of the second laser in the present invention;

[0036] Figure 5 It is an axonometric view of the installation position of the cooling unit in the present invention;

[0037] Figure 6 It is an axonometric view of the installation position of the battery cell transmission part in the present invention;

[0038] Figure 7 It is a schematic diagram of the moving direction of the cell transmission part relative to the laser assembly and the cooling part in the present invention;

[0039] Figure 8 It is a schematic diagram of the movement of the laser assembly and the cooling part relative to the cell transmission part in the present invention;

[0040] Figures 1 to 7 This is the first embodiment of the present invention. Figure 8 This is the second embodiment of the present invention.

[0041] In the figure, 10. fixing frame, 20. laser assembly, 20-1. first laser, 20-2. second laser, 23. first laser up and down fine-tuning assembly, 24. first laser horizontal fine-tuning assembly, 25. second laser fine-tuning assembly, 26. first connecting plate, 27. second connecting plate, 28. column, 30. battery cell transmission part, 31. horizontal drive assembly, 32. lifting drive assembly, 33. receiving platform, 40. cooling part, 41. nozzle, 42. nozzle front and rear position fine-tuning assembly, 43. nozzle left and right position fine-tuning assembly, 100. battery cell, 100-1 to be split line.

[0042] Since the laser itself has its own frequency, the dividing line is actually composed of countless dividing points. The dividing lines described in the following embodiments all include dividing points. DETAILED DESCRIPTION

[0043] Combine the following Figures 1 to 8 Embodiments of the present invention will be described.

[0044] Embodiment 1:

[0045] Figure 1The method for cutting a solar cell is illustrated. The first laser beam and the second laser beam are simultaneously focused on the position of the to-be-split line 100-1 of the cell 100, wherein the first laser beam draws a splitting line of a certain length along the to-be-split line 100-1 on the surface of one end of the cell 100, and the splitting line is not enough to break the cell, and the second laser beam heats the cell along the to-be-split line 100-1 of the cell, so that the cell 100 is disconnected from the to-be-split line 100-1, and while the above two laser beams act on the cell 100 to be cut, a cooling medium is sprayed on the position of the to-be-split line 100-1 of the cell 100, and due to the effect of the cooling medium, the temperature of the cut portion of the cell 100 is always low, and the fracture stress of the cell 100 material is reduced, so that there is no accumulation at the crack of the cell 100.

[0046] Figure 2 The overall components of the cutting device are shown in the figure. Among them, the fixing frame 10 is arranged at the bottom of the cutting device, and is used to receive and install the components for transporting the battery sheet 100 and generating the first laser beam and the second laser beam respectively;

[0047] The cell transfer unit 30 is installed on the fixing frame 10, and is used to move each solar cell 100 to be cut along the path of the splitting line 100-1 relative to the focus point of the first laser beam and the second laser beam to achieve the splitting of the cell;

[0048] The laser assembly 20 is mounted on the fixing frame 10 and is located above the cell transmission unit 30 , and is used to generate a first laser beam and a second laser beam.

[0049] The cooling unit 40 is mounted on the fixing frame 10 and is located above the cell transfer unit 30 . When two laser beams act on the cell 100 to be cut, the cooling unit 40 is used to spray a cooling medium on the position of the splitting line 100 - 1 of the cell 100 .

[0050] Figure 3 The installation position and structural composition of the first laser 20-1 are illustrated. The column 28 is installed on the fixing frame 10, the first connecting plate 26 is installed on the column 28 and can be adjusted up and down, the back of the first connecting plate 26 is provided with a first laser up and down fine-tuning component 23 and a first laser horizontal fine-tuning component 24, and the first laser 20-1 is installed on the first laser up and down fine-tuning component 23 and the first laser horizontal fine-tuning component 24;

[0051] The vertical distance of the first laser 20-1 relative to the battery cell 100 can be roughly adjusted by the first connecting plate 26, and then finely adjusted by the first laser up and down fine-tuning component 23. The horizontal position of the first laser 20-1 can be finely adjusted by the first laser horizontal fine-tuning component 24, so that the focal point of the first laser beam is located on the line 100-1 to be split of the battery cell 100.

[0052] Figure 4 The installation position and structural composition of the second laser 20-2 are illustrated. The second connecting plate 27 is installed on the column 28 and can be adjusted up and down. The second laser fine-tuning component 25 is installed on the second connecting plate 27 at a certain angle, and the second laser 20-2 is installed on the second laser fine-tuning component 25;

[0053] The distance of the second laser 20-2 relative to the battery cell can be roughly adjusted by the second connecting plate 27 and then finely adjusted by the second laser fine-tuning assembly 25, so that the focal point of the second laser beam is located on the line 100-1 to be split of the battery cell 100 and coincides with the focal point of the first laser.

[0054] Figure 5 The installation position of the cooling unit 40 is shown. The front of the first connecting plate 26 is provided with a nozzle front and rear position fine-tuning component 42 and a nozzle left and right position fine-tuning component 43, which can be adjusted up and down. The cooling unit 40 is installed on the nozzle front and rear position fine-tuning component 42 and the nozzle left and right position fine-tuning component 43. The cooling unit 40 also includes a nozzle 41, and the nozzle 41 can also be two;

[0055] The distance between the cooling part 40 and the battery cell can be roughly adjusted by the second connecting plate 27, and then finely adjusted by the nozzle front and rear position fine adjustment component 42 and the nozzle left and right position fine adjustment component 43, so that the cooling medium sprayed by the nozzle 41 acts on the to-be-split line 100-1 of the battery cell 100 and coincides with the focus point of the first laser beam and the second laser beam;

[0056] The cooling medium is preferably deionized water, and other cooling media may also be used, such as using cold air to blow at the line 100 - 1 to be split.

[0057] Figure 6 The installation position and structural composition of the cell transmission unit 30 are shown in the figure. The horizontal drive assembly 31 is installed on the fixing frame 10, the lifting drive assembly 32 is arranged on the horizontal drive assembly 31, and the lifting drive assembly 32 is also provided with a receiving platform 33;

[0058] The horizontal drive assembly 31 can reciprocate along the direction of the to-be-split line 100-1, and the mechanical structure used includes but is not limited to: a guide rail screw mechanism driven by a motor, a gear rack mechanism, a guide rail belt transmission mechanism or a cylinder transmission mechanism driven by compressed air;

[0059] The lifting drive assembly 32 can reciprocate in a direction perpendicular to the battery sheet 100, and can reciprocate along the direction of the to-be-split line 100-1 driven by the horizontal drive assembly 31. The mechanical structure used includes but is not limited to: a guide rail screw mechanism driven by a motor, a gear rack mechanism, a guide rail belt transmission mechanism, or a cylinder transmission mechanism driven by compressed air;

[0060] The receiving platform 33 fixes the battery cell 100 on its upper surface by vacuum adsorption, so as to ensure that the relative position of the battery cell 100 does not change during transportation.

[0061] Figure 7 The schematic diagram shows the movement direction of each component when the battery cell 100 is cut. The first laser 20-1, the second laser 20-2 and the cooling unit 40 are fixedly arranged, and the battery cell transmission unit 30 moves with the battery cell 100 in the direction of the arrow to complete the cutting of the battery cell.

[0062] Second embodiment:

[0063] Figure 8 The diagram shows the movement direction of each component when the battery cell 100 is cut. The difference between the second embodiment and the first embodiment is that the receiving platform 33 and the battery cell 100 are fixedly arranged, and the first laser 20-1, the second laser 20-2 and the cooling part 40 can move in the direction of the arrow under the drive of the motion mechanism to complete the cutting of the battery cell 100.

[0064] Working principle: Manually adjust the first laser up and down fine-tuning assembly 23 and the first laser horizontal fine-tuning assembly 24, so that the focal point of the laser emitted by the first laser 20-1 is located on the line 100-1 to be split in the middle of the battery cell 100; manually adjust the second laser fine-tuning assembly 25, so that the focal point of the laser emitted by the second laser 20-2 coincides with the focal point of the first laser. Manually adjust the nozzle front and rear position fine-tuning assembly 42 and the nozzle left and right position fine-tuning assembly 43, so that the cooling medium sprayed by the nozzle 41 acts on the focal points of the two laser beams;

[0065] The lifting drive assembly 32 moves to the front end of the equipment driven by the horizontal drive assembly 31, and the receiving platform 33 rises to the highest point to receive the battery cell 100 supplied by the previous station. When the battery cell 100 is placed on the receiving platform 33, the battery cell 100 is fixed at the center of the receiving platform 33, and the horizontal drive assembly 31 starts to drive the lifting drive assembly 32 and the receiving platform 33 to move at least one battery cell 100 to the rear of the equipment;

[0066] During the movement, the focal points of the first laser beam and the second laser beam scan the to-be-split line 100 - 1 of the cell to complete the cutting of the cell 100 ;

[0067] The cut battery cell 100 is no longer fixed on the receiving platform 33, and the battery cell 100 is transferred to the next workstation. The receiving platform 33 is lowered to a low position and moved back to the front end of the equipment, waiting for the next battery cell 100 to be cut to arrive.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for cutting a solar cell sheet, characterized in that: The first laser beam and the second laser beam are simultaneously focused on the position of the battery cell to be split, wherein the first laser beam cuts a splitting line of a certain length on the surface of one end of the battery cell (100), and the second laser beam heats the battery cell (100) along the splitting line and its extension line, and simultaneously sprays a cooling medium along the line (100-1) to be split of the battery cell (100), so as to reduce the fracture stress of the material below the splitting line and the extension line of the splitting line of the battery cell (100) and cause the battery cell (100) to break; The first laser beam, the second laser beam and the sprayed cooling medium are focused on the same starting point of the to-be-split line (100-1) of the battery cell (100); During the process of the first laser beam, the second laser beam and the cooling medium acting on the battery cell, the first laser beam, the second laser beam and the cooling medium move relative to the battery cell (100) along the direction of the line to be split, or the battery cell moves relative to the first laser beam, the second laser beam and the cooling medium along the direction of the line to be split (100-1).

2. The method for cutting a solar cell sheet according to claim 1, characterized in that: The first laser beam is a pulsed laser beam, which is used to draw a dividing line on the battery cell (100).

3. The method for cutting a solar cell sheet according to claim 1 or 2, characterized in that: The second laser beam is a continuous thermal laser beam, which performs a heating action on the cell sheet (100) dividing line and its extension line.

4. The method for cutting a solar cell sheet according to claim 1, wherein: The splitting line formed by the first laser beam on the surface of the cell sheet (100) is a discontinuous or continuous splitting line along the direction of the line to be split of the cell sheet (100).

5. The method for cutting a solar cell sheet according to claim 1, wherein: The distance between the first laser beam and the second laser beam reaching the inside of the battery cell and the surface of the battery cell (100) is achieved by adjusting the height position of the battery cell (100).

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