A method for manufacturing a solar cell and a solar cell

Abstract

The application provides a preparation method of a solar cell and the solar cell, and relates to the technical field of solar cell preparation. The preparation method of the solar cell can comprise the following steps: preparing a functional layer on a substrate after texturing cleaning, placing the first cell structure in a carrier plate, performing physical vapor deposition on two side surfaces of the first cell structure to form a transparent conductive layer, and performing optical detection on the second cell structure to determine whether the transparent conductive layer on the two sides of the second cell structure is formed in a wrap-around plating mode. If the transparent conductive layer is formed in the wrap-around plating mode, the position of the wrap-around plating needs to be etched, so that the transparent conductive layer on the two sides of the second cell structure is disconnected, and the yield of the solar cell preparation is improved.

Description

Technical Field

[0001] This invention relates to the field of solar cell fabrication technology, and in particular to a method for fabricating a solar cell and the solar cell itself. Background Technology

[0002] The fabrication process of solar cells generally includes steps such as cleaning and texturing the silicon wafer, CVD fabrication of the functional layer on the N / P side, PVD sputtering of the transparent conductive layer on the N / P side, and screen printing of metal electrodes. In the plate-type horizontal conveyor PVD coating process, to meet the capacity requirements of mass production, the N / P side PVD sputtering process generally uses the same cavity to place the silicon wafer on a high-capacity carrier plate, and deposits both sides simultaneously, generally with the N side facing upwards (to obtain higher ISC and improve the light utilization of the N side, the N side is fully coated with a PVD blue film). The P side faces downwards and contacts the edge of the carrier plate. This results in the area of ​​the P side in contact with the edge of the carrier plate not being sputtered with the PVD blue film, and the P side cannot be fully coated with the TCO blue film, reducing the light-receiving area of ​​the P side and resulting in lower light utilization. Currently, the width of the carrier plate edge support is generally 0.7-1.0 mm. In order to maximize the coating area of ​​the TCO on the P side, the width of the carrier plate edge support baffle needs to be minimized during the PVD carrier plate fabrication process. However, as the width of the support baffle at the edge of the carrier plate becomes narrower, due to manufacturing errors of the silicon wafer and carrier plate, as well as positional errors of the silicon wafer placed on the carrier plate, some areas of the P-side of the silicon wafer are not blocked by the carrier plate. This can lead to the problem of N / P side wrapping during the coating process. Wrapping can cause the N / P side of the subsequently prepared battery to be short-circuited, resulting in high resistance and low Eta efficiency. Summary of the Invention

[0003] A first aspect of this invention aims to provide a method for fabricating a solar cell, solving the problems of short circuits and winding caused by the small width of the carrier plate during the fabrication of solar cells in the prior art.

[0004] A second aspect of the present invention is to provide a solar cell.

[0005] Specifically, the present invention provides a method for preparing a solar cell, comprising:

[0006] A substrate is provided, and the substrate is cleaned and texturized.

[0007] Functional layers are fabricated on the front and back sides of the substrate to form a first battery structure;

[0008] The first battery structure is placed on a carrier plate, and a transparent conductive layer is prepared on both sides of the first battery structure by physical vapor deposition to form a second battery structure.

[0009] The second battery structure is subjected to a first optical inspection to determine whether the transparent conductive layer on the front and back sides of the second battery structure has a circumferential coating.

[0010] When the transparent conductive layer on the front and back sides of the second battery structure is coated with a coating, the coating location is etched.

[0011] When no winding plating occurs on the transparent conductive layer on the front and back sides of the second battery structure, electrodes are printed on the transparent conductive layer of the second battery structure to form a solar cell.

[0012] Optionally, the carrier plate includes a support portion for supporting the first battery structure, the width of which is 0.05mm to 0.1mm.

[0013] Optionally, when the transparent conductive layer on the front and back sides of the second battery structure is coated with a plating layer, after etching the transparent conductive layer on the front and back sides at the plating location, the method further includes:

[0014] A second optical inspection is performed on the etched second battery structure to determine whether the transparent conductive layer on the front and back sides of the second battery structure exhibits overlay.

[0015] When the transparent conductive layer on the front and back sides of the second battery structure is coated with a coating, the coating position is etched.

[0016] When no wrap-around plating occurs on the transparent conductive layer of the second battery structure on the front and back sides, electrodes are printed on the transparent conductive layer of the second battery structure.

[0017] Optionally, the etching method for the area to be coated can be selected from one of the following: wet etching, plasma dry etching, laser etching, inkjet printing, screen printing, automatic dispensing, or roller coating.

[0018] Optionally, both the first optical inspection and the second optical inspection are performed using automated optical inspection.

[0019] Optionally, after forming a solar cell by printing electrodes on the transparent conductive layer of the second battery structure, the method further includes:

[0020] The performance of the solar cell is tested, and it is determined whether the performance of the solar cell is abnormal.

[0021] When the performance of the solar cell is abnormal, the solar cell is re-optically inspected, and the abnormality of the solar cell is determined again.

[0022] Optionally, when the performance of the solar cell is abnormal, the steps of re-performing optical inspection on the solar cell and re-determining the abnormality of the solar cell include:

[0023] When the performance of the solar cell is abnormal, optical detection is performed on the solar cell;

[0024] Determine whether there is any entanglement plating on the conductive layers of the front and back sides of the solar cell;

[0025] If so, the location where the solar cell has a coating is etched.

[0026] Repeat the steps of performing performance testing on the solar cell.

[0027] Optionally, the step after forming a solar cell by printing electrodes on the transparent conductive layer of the second battery structure includes:

[0028] The parallel resistance, leakage current, Rs, and Isc of the solar cell are detected and monitored.

[0029] The performance of the solar cell is deemed abnormal when one or more of the following parameters are abnormal: parallel resistance, leakage current, Rs, or Isc.

[0030] Optionally, forming a first battery structure by fabricating functional layers on the front and back sides of the substrate includes:

[0031] A functional layer is prepared on the front and back sides of the substrate by chemical vapor deposition. The functional layer includes a passivation layer and a doped layer on the passivation layer.

[0032] In particular, the present invention also provides a solar cell prepared according to the solar cell preparation method described above.

[0033] The method for fabricating solar cells in this scheme involves placing a first cell structure on a carrier plate, forming a transparent conductive layer on both sides of the first cell structure using physical vapor deposition, and then performing optical inspection on the second cell structure to determine whether the transparent conductive layer on both sides of the second cell structure has formed a wrap-around coating. If a wrap-around coating is formed, the wrap-around coating position needs to be etched to ensure that the transparent conductive layer on both sides of the second cell structure is disconnected, thereby improving the yield of solar cell fabrication.

[0034] The width of the support edge in this design can be between 0.05mm and 0.1mm. This width minimizes obstruction to the back of the first battery structure, thereby increasing the area of ​​the transparent conductive layer on the back and ultimately improving the overall efficiency of the battery cell. This design combines the narrow support with the inspection and etching of the conductive layer after fabrication. This increases the area of ​​the transparent conductive layer, improves light utilization, and enhances battery efficiency, while ensuring that the transparent conductive layers on the front and back of the battery are disconnected from each other, preventing short circuits.

[0035] After etching the second battery structure with the wrap-around plating detected by the first optical inspection, this solution will perform a second optical inspection to avoid incomplete etching. The double optical inspection can reduce the risk of wrap-around plating and minimize the risk of short circuits between the transparent conductive layers on the front and back sides caused by wrap-around plating.

[0036] After the solar cells are formed, this solution will also perform performance testing on them, which can further increase the confirmation of the defect rate of the solar cells. For some solar cells with abnormal performance, they can return to the optical testing step to reconfirm whether the edge area of ​​the solar cell is coated, thereby further reducing the possibility of abnormal performance of the entire cell due to coating.

[0037] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0038] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0039] Figure 1 This is a schematic flowchart illustrating a method for fabricating a solar cell according to a specific embodiment of the present invention;

[0040] Figure 2 This is a schematic flowchart illustrating a method for fabricating a solar cell according to another specific embodiment of the present invention;

[0041] Figure 3 This is a schematic flowchart of a method for preparing a solar cell according to yet another specific embodiment of the present invention;

[0042] Figure 4 This is a schematic flowchart illustrating the steps after forming a solar cell by printing electrodes on the transparent conductive layer of a second battery structure according to a specific embodiment of the present invention. Detailed Implementation

[0043] In the description of this embodiment, it should be understood that the terms "length", "width", "height", "up", "down", "left", "right", "vertical", "horizontal", "bottom", "inner", "outer", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0044] As a specific embodiment of the present invention, such as Figure 1 As shown, this embodiment provides a method for fabricating a solar cell, which may include:

[0045] Step S100: Provide a substrate and clean and texturize the substrate;

[0046] Step S200: Functional layers are prepared on the front and back sides of the substrate to form the first battery structure;

[0047] Step S300: Place the first battery structure on the carrier plate, and use physical vapor deposition to prepare transparent conductive layers on both sides of the first battery structure to form the second battery structure.

[0048] Step S400: Perform a first optical inspection on the second battery structure to determine whether there is a wrap-around plating on the transparent conductive layer on the front and back of the second battery structure; if yes, proceed to step S500; otherwise, proceed to step S600.

[0049] Step S500: Etch the area where the plating is applied.

[0050] In step S600, electrodes are printed on the transparent conductive layer of the second battery structure to form a solar cell.

[0051] Specifically, the substrate in this embodiment can be a whole silicon wafer or a half silicon wafer.

[0052] Specifically, in this embodiment, a first battery structure is placed on a carrier plate, and a transparent conductive layer is formed on both sides of the first battery structure by physical vapor deposition. The second battery structure is then subjected to optical inspection to determine whether the transparent conductive layer on both sides of the second battery structure has formed a wrap-around plating. If a wrap-around plating is formed, the wrap-around plating position needs to be etched to ensure that the transparent conductive layer on both sides of the second battery structure is disconnected, thereby improving the yield of solar cell fabrication.

[0053] Specifically, step S200 of this embodiment, which involves fabricating functional layers on the front and back sides of the substrate to form the first battery structure, includes:

[0054] Functional layers are prepared on the front and back sides of a substrate using chemical vapor deposition. The functional layers include a passivation layer and a doped layer located on the passivation layer.

[0055] The doped layer on the front side can be an N-type doped amorphous silicon or microcrystalline silicon thin film, while the doped layer on the back side can be a P-type doped amorphous silicon or microcrystalline silicon thin film.

[0056] As a specific embodiment of the present invention, the carrier plate of this embodiment may include a support portion for supporting the first battery structure, and the width of the edge of the support portion is 0.05mm to 0.1mm.

[0057] Specifically, a carrier plate in this embodiment may include multiple support portions, each support portion having a through hole in the middle, and the edge of the through hole having a step, the step having a certain support width. The shape of the support portion is consistent with the shape of the battery to be supported, and is generally the size of a whole or half silicon wafer.

[0058] The width of the support edge in this embodiment can be between 0.05mm and 0.1mm, for example, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, or 0.1mm. This width of support minimizes obstruction to the back of the first battery structure, thereby increasing the area of ​​the transparent conductive layer on the back and improving the overall efficiency of the battery cell. However, due to manufacturing errors in the silicon wafer and carrier plate, as well as errors in the position of the silicon wafer during placement on the carrier plate, the carrier plate may not completely obstruct the back of the first battery structure, leading to plating around the transparent conductive layer during fabrication. This embodiment combines a narrow support with detection of plating around the transparent conductive layer after fabrication. This increases the area of ​​the transparent conductive layer, improves light utilization, and increases battery efficiency, while ensuring that the transparent conductive layers on the front and back of the battery are disconnected from each other, preventing short circuits.

[0059] As a specific embodiment of the present invention, such as Figure 2 As shown, in this embodiment, after etching the transparent conductive layers on the front and back sides at the locations where the transparent conductive layers are plated around the front and back sides of the second battery structure, the method further includes:

[0060] Step S700: Perform a second optical inspection on the etched second cell structure;

[0061] In step S800, determine whether there is a wrap-around plating on the transparent conductive layer on the front and back of the second battery structure; if yes, repeat step S500; otherwise, repeat step S600.

[0062] Specifically, in this embodiment, after etching the second battery structure with the wrap-around plating detected by the first optical inspection, a second optical inspection will be performed to avoid incomplete etching. The double optical inspection can reduce the risk of wrap-around plating and minimize the risk of short circuit between the transparent conductive layers on the front and back sides caused by wrap-around plating.

[0063] Specifically, in this embodiment, the etching method for the area to be coated is selected from one of the following: wet etching, plasma dry etching, laser etching, inkjet printing, screen printing, automatic dispensing, or roller coating.

[0064] Specifically, in this embodiment, etching is mainly performed on the edge of the silicon wafer or the back of the silicon wafer near the edge where the coating is applied. The width of the etching is also as narrow as possible, basically smaller than the width of the substrate edge.

[0065] Among etching methods, wet etching, plasma etching, and laser etching can directly etch the battery structure. Inkjet printing, screen printing, automatic dispensing, or roller coating involve first applying ink or a special etching adhesive to the edges of the areas to be etched, then using the ink or adhesive to etch the transparent conductive layer, thus cutting through the transparent conductive layer on both sides of the silicon wafer. In the etching process, firstly, the etching material must maintain a high etching rate, and secondly, the equipment must control the positional accuracy of the etched area to prevent other normal blue film (i.e., transparent conductive layer) areas from being unaffected.

[0066] Specifically, in this embodiment, both the first and second optical inspections are performed using automated optical inspection, i.e., AOI (Automated Optical Inspection).

[0067] Automated Optical Inspection (AOI) primarily performs a full scan inspection of any remaining transparent conductive layer at the edges of silicon wafers. The AOI results determine whether any transparent conductive layer residue remains on the wafer's edges. Areas with residual transparent conductive layer can then be etched. AOI continues until the etching effect is satisfactory (i.e., the transparent conductive layer on both the front and back sides is completely severed), at which point the AOI inspection stops, and the wafer proceeds to the next process. AOI inspection aims to maintain a short production cycle time to ensure a low false positive rate.

[0068] As a specific embodiment of the present invention, such as Figure 3 As shown, step S600 of this embodiment, after printing electrodes on the transparent conductive layer of the second battery structure to form a solar cell, may further include:

[0069] Step S900: Perform performance testing on the solar cell;

[0070] Step S1000: Determine if the performance of the solar cell is abnormal;

[0071] If yes, proceed to step S1100; otherwise, terminate the entire production process.

[0072] Step S1100: Perform optical inspection on the solar cell;

[0073] Step S1200: Determine whether there is any swivel coating on the transparent conductive layer on the front and back of the solar cell;

[0074] If yes, proceed to step S1300; otherwise, end the entire production process.

[0075] Step S1300: Etch the location where the solar cell is coated;

[0076] After etching the solar cell, repeat the steps after step S900.

[0077] In this embodiment, after the solar cell is formed, its performance is tested to further increase the confirmation of the defect rate of the solar cell. For some solar cells with abnormal performance, the optical testing step can be returned to confirm whether the edge area of ​​the solar cell is coated, thereby further reducing the possibility of abnormal performance of the entire cell due to coating.

[0078] Specifically, such as Figure 4 As shown, in this embodiment, the steps after forming a solar cell by printing electrodes on the transparent conductive layer of the second battery structure may include:

[0079] Step S910: The parallel resistance, leakage current, Rs and Isc of the solar cell are detected and monitored.

[0080] Step S920: When one or more of the following indicators are abnormal: parallel resistance, leakage current, Rs or Isc, the performance of the solar cell is determined to be abnormal.

[0081] This embodiment detects the parallel resistance, leakage current, Rs or Isc of the solar cell. When these manufacturing abnormalities are detected, it indicates that the performance of the solar cell is abnormal. For solar cells with abnormal performance, the abnormal solar cells can be returned to the previous production line for further testing and etching, thereby reducing the defect rate of solar cells.

[0082] As a specific embodiment of the present invention, this embodiment provides a solar cell, which is prepared according to the above-described method for preparing solar cells.

[0083] Specifically, during the fabrication of the solar cell, when the edge width of the carrier plate in the comparative example was 0.6 mm, the performance of the resulting solar cell is shown in the table below. In this embodiment, when the edge width of the carrier plate was reduced to 0.3 mm, the performance of the final solar cell is shown in the table below. Ultimately, compared to the comparative example, this embodiment shows an improvement of 60–80 mA in Isc and an improvement of over 0.2% in Eta. Specific data are shown in the table below.

[0084]

[0085] Furthermore, in the process of preparing solar cells using the solar energy preparation method of this embodiment, the yield rate is increased by 5% to 10% because defective products can be re-inspected and reproduced.

[0086] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A method for preparing a solar cell, characterized in that, include: A substrate is provided, and the substrate is cleaned and texturized. Functional layers are fabricated on the front and back sides of the substrate to form a first battery structure; The first battery structure is placed on a carrier plate, and a transparent conductive layer is prepared on both sides of the first battery structure by physical vapor deposition to form a second battery structure. The second battery structure is subjected to a first optical inspection to determine whether the transparent conductive layer on the front and back sides of the second battery structure has a circumferential coating. When the transparent conductive layer on the front and back sides of the second battery structure is coated with a coating, the coating location is etched. When no winding plating occurs on the transparent conductive layer on the front and back sides of the second battery structure, electrodes are printed on the transparent conductive layer of the second battery structure to form a solar cell.

2. The method for preparing a solar cell according to claim 1, characterized in that, The carrier plate includes a support portion for supporting the first battery structure, the width of which is 0.05mm to 0.1mm.

3. The method for preparing a solar cell according to claim 1, characterized in that, When the transparent conductive layer on the front and back sides of the second battery structure is coated with a plating layer, after etching the transparent conductive layer on the front and back sides at the plating location, the process further includes: A second optical inspection is performed on the etched second battery structure to determine whether the transparent conductive layer on the front and back sides of the second battery structure exhibits overlay. When the transparent conductive layer on the front and back sides of the second battery structure is coated with a coating, the coating position is etched. When no wrap-around plating occurs on the transparent conductive layer of the second battery structure on the front and back sides, electrodes are printed on the transparent conductive layer of the second battery structure.

4. The method for preparing a solar cell according to claim 1, characterized in that, The etching method for the area to be plated is selected from one of the following: wet etching, plasma dry etching, laser etching, inkjet printing, screen printing, automatic dispensing, or roller coating.

5. The method for preparing a solar cell according to claim 3, characterized in that, Both the first and second optical inspections were performed using automated optical inspection.

6. The method for preparing a solar cell according to claim 3, characterized in that, After forming a solar cell by printing electrodes on the transparent conductive layer of the second battery structure, the following steps are also included: The performance of the solar cell is tested, and it is determined whether the performance of the solar cell is abnormal. When the performance of the solar cell is abnormal, the solar cell is re-optically inspected, and the abnormality of the solar cell is determined again.

7. The method for preparing a solar cell according to claim 6, characterized in that, When the performance of the solar cell is abnormal, the steps of re-performing optical inspection on the solar cell and re-determining the abnormality of the solar cell include: When the performance of the solar cell is abnormal, optical detection is performed on the solar cell; Determine whether there is any entanglement plating on the conductive layers of the front and back sides of the solar cell; If so, the location where the solar cell has a coating is etched. Repeat the steps of performing performance testing on the solar cell.

8. The method for preparing a solar cell according to claim 1, characterized in that, The steps following the formation of a solar cell by printing electrodes on the transparent conductive layer of the second battery structure include: The parallel resistance, leakage current, Rs, and Isc of the solar cell are detected and monitored. The performance of the solar cell is deemed abnormal when one or more of the following parameters are abnormal: parallel resistance, leakage current, Rs, or Isc.

9. The method for preparing a solar cell according to claim 1, characterized in that, The formation of a first battery structure by fabricating functional layers on the front and back sides of the substrate includes: A functional layer is prepared on the front and back sides of the substrate by chemical vapor deposition. The functional layer includes a passivation layer and a doped layer on the passivation layer.

10. A solar cell, characterized in that, The solar cell is prepared according to the method described in any one of claims 1-9.

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