Solar cell back-etching cleaning device and solar cell preparation system
By designing a solar cell re-etching cleaning device and adopting a spraying method with gradually decreasing concentration of re-etching solution, the problem of damage to transparent conductive films during the re-etching cleaning process was solved, thereby improving the efficiency and yield of solar cells.
Patent Information
- Application Number
- CN202520052037.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-09
- Publication Date
- 2026-01-27
- Estimated Expiration
- 2035-01-09
AI Technical Summary
In existing technologies, transparent conductive films are easily damaged during the etching and cleaning process, leading to a decrease in solar cell efficiency.
A solar cell etching cleaning device is designed. The device uses multiple spray units to spray etching liquid of different concentrations, gradually reducing the concentration to ensure that the metal seed layer is completely removed without damaging the transparent conductive film.
This effectively avoids damage to the transparent conductive film, improves the product yield of solar cells, and prevents color difference and efficiency reduction.
Smart Images
Figure CN223844167U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of solar cell fabrication technology, and in particular to a solar cell etch cleaning device and a solar cell fabrication system. Background Technology
[0002] In the fabrication process of solar cells, a transparent conductive film is first deposited on the solar cell substrate, and then grid electrodes are fabricated on the transparent conductive film. The transparent conductive film serves to collect and transmit current and reduce reflection; its photoelectric properties directly affect the performance of the solar cell, especially its fill factor.
[0003] When fabricating grid electrodes on a transparent conductive film using metal electroplating, a metal seed layer is first formed on the transparent conductive film using PVD magnetron sputtering. A photosensitive emulsion layer is then coated onto the metal seed layer. The grid pattern is printed onto the photosensitive emulsion layer and exposed. Next, the portion of the photosensitive emulsion layer with the printed grid pattern is removed using a developing solution to form grooves in the photosensitive emulsion layer. Metal grid lines are then electroplated within these grooves, and excess photosensitive emulsion is removed. Finally, the solar cell is etched back using an etching solution to remove the metal seed layer. Transparent conductive films are typically fabricated through a coating process. If the coating process of the transparent conductive film malfunctions, the etch-back cleaning step can damage the transparent conductive film, leading to color differences in the solar cell and preventing the generated current from being effectively transmitted to the grid lines, resulting in reduced solar cell efficiency. Utility Model Content
[0004] Based on this, this application provides a solar cell etch-back cleaning apparatus and a solar cell fabrication system to solve the technical problem of reduced solar cell efficiency caused by damage to the transparent conductive film during the etch-back cleaning step in the prior art.
[0005] In a first aspect, one embodiment of this application provides a solar cell etch-back cleaning apparatus, comprising:
[0006] The conveying mechanism includes a plurality of first conveying units, second conveying units, and third conveying units arranged sequentially along the conveying direction of the solar cells; the first conveying unit, the second conveying unit, and the third conveying unit each include a plurality of rollers arranged at intervals along the conveying direction of the solar cells.
[0007] Multiple etch-back spraying units are respectively located above the corresponding first conveying units and are used to spray etch-back liquid of different concentrations. Along the conveying direction of the solar cell, the concentration of the etch-back liquid sprayed by the multiple etch-back spraying units gradually decreases.
[0008] A cleaning spray unit is provided above the third conveying unit, and the cleaning spray unit is used to spray cleaning liquid.
[0009] Optionally, the spray surface of the etched spray unit is parallel to the upper surface of the solar cell.
[0010] Optionally, the spray surface of the back-etching spray unit includes a first spray surface, a second spray surface, and a third spray surface connected in sequence. The second spray surface is parallel to the upper surface of the solar cell, and the first spray surface and the third spray surface are arranged obliquely and symmetrically.
[0011] Optionally, the back-etching spray unit includes a first nozzle, a first liquid storage tank, and a first pipeline for connecting the first nozzle and the first liquid storage tank, wherein the first liquid storage tank is used to store the back-etching liquid;
[0012] The cleaning spray unit includes a second nozzle, a second liquid storage tank, and a second pipeline for connecting the second nozzle and the second liquid storage tank, wherein the second liquid storage tank is used to store the cleaning liquid.
[0013] Optionally, the solar cell re-etching cleaning device includes three of the re-etching spray units.
[0014] Optionally, the solar cell re-etching and cleaning device further includes a re-etching tank, and a plurality of the first conveying units are respectively disposed in the re-etching tank.
[0015] Optionally, the second conveying unit and the third conveying unit are respectively disposed in the return groove.
[0016] Optionally, the solar cell re-etching and cleaning device further includes a cleaning tank, and the third conveying unit is disposed in the cleaning tank.
[0017] Optionally, the roller includes a roller shaft and a plurality of rollers sleeved on the roller shaft.
[0018] Secondly, one embodiment of this application provides a solar cell fabrication system, including the aforementioned solar cell etching and cleaning apparatus.
[0019] The solar cell etching cleaning apparatus and solar cell fabrication system of this application include a plurality of first conveying units, second conveying units, and third conveying units arranged sequentially along the conveying direction of the solar cell; a plurality of etching spraying units corresponding to the plurality of first conveying units, wherein the concentration of the etching solution sprayed by the plurality of etching spraying units gradually decreases; and a cleaning spraying unit disposed above the third conveying unit. Through the above method, during the etching cleaning process of the solar cell, as the concentration of the etching solution sprayed by the plurality of etching spraying units gradually decreases along the conveying direction of the solar cell, the solar cell undergoes multiple etching processes with gradually decreasing etching capacity using the etching solution of gradually decreasing concentration. When it reaches the second conveying unit, the etching solution concentration remaining on the surface of the solar cell is low. During the conveying process in the second conveying unit, the etching continues with a lower etching capacity. After the metal seed layer is completely etched, the low-concentration etching solution in contact with the transparent conductive film will not damage the transparent conductive film. This ensures the etching effect of the metal seed layer while avoiding damage to the transparent conductive film, preventing color difference and efficiency reduction in the solar cell after etching cleaning, and improving the product yield of the solar cell. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the structure of a solar cell etch cleaning apparatus according to an embodiment of this application.
[0021] Figure 2 for Figure 1 The side view of the solar cell etching and cleaning device shown.
[0022] Figure 3 This is a schematic diagram of the solar cell structure before it was cleaned and re-etched.
[0023] Figure 4 This is a schematic diagram of the structure of a solar cell after etching and cleaning.
[0024] Figure 5 for Figure 1 The diagram shows a schematic of the spray surface of the re-etching spray unit in the solar cell re-etching cleaning device.
[0025] Figure 6 for Figure 1 The diagram shows the structure of another spray surface of the re-etching spray unit in the solar cell re-etching cleaning device.
[0026] Figure 7 for Figure 1 The diagram shows the structure of another spray surface of the re-etching spray unit in the solar cell re-etching cleaning device.
[0027] Figure 8 for Figure 1 The diagram shows the structure of the etching spray unit in the solar cell etching cleaning device.
[0028] Figure 9 for Figure 1 The diagram shows the structure of the rollers in the solar cell re-etching and cleaning device.
[0029] Figure 10 for Figure 1 The diagram shows the interaction between the rollers and the solar cells in the solar cell re-etching and cleaning device.
[0030] Figure 11 This is a schematic diagram of the structure of a solar cell etch cleaning apparatus according to an embodiment of this application.
[0031] Figure 12 This is a schematic diagram of the structure of a solar cell etch cleaning apparatus according to an embodiment of this application.
[0032] The meanings of the labels in the attached diagram are as follows:
[0033] 100 - Solar cell; 10 - Conveying mechanism; S1 - Conveying direction; 11 - First conveying unit; 12 - Second conveying unit; 13 - Third conveying unit; 10a - Roller; 101 - Roller shaft; 1011 - End; 102 - Drum; 103 - Notch; 20 - Re-etching spray unit; 21a - Spray surface; 21b - Spray surface; 21b1 - First spray surface; 21b2 - Second spray surface; 21b3 - Third spray surface; 21 - First nozzle; 22 - First liquid reservoir 1. Tank; 23. First pipeline; 30. Cleaning spray unit; 40. Re-etching groove; 50. Cleaning tank; 111. Silicon wafer substrate; 121. First intrinsic amorphous silicon layer; 122. Second intrinsic amorphous silicon layer; 131. N-type doped amorphous silicon layer; 132. P-type doped amorphous silicon layer; 141. Transparent conductive film; 151. First metal seed layer; 152. Second metal seed layer; 16. Metal gate line; 161. Metal seed layer; 162. Metal gate line layer; 163. Protective layer. Detailed Implementation
[0034] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.
[0035] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.
[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
[0037] like Figures 1 to 12 As shown, this is a solar cell re-etching and cleaning apparatus according to one embodiment of this application.
[0038] like Figure 1 and Figure 2 As shown, the solar cell re-etching and cleaning device includes a conveying mechanism 10, a re-etching spray unit 20, and a cleaning spray unit 30.
[0039] The conveying mechanism 10 is used to transport the solar cell 100 during the back-etching and cleaning process. The conveying mechanism 10 includes a plurality of first conveying units 11, second conveying units 12 and third conveying units 13, which are arranged sequentially along the conveying direction S1 of the solar cell 100. Each first conveying unit 11, second conveying unit 12 and third conveying unit 13 includes a plurality of rollers 10a arranged at intervals along the conveying direction S1 of the solar cell 100.
[0040] Multiple etching return spray units 20 are provided, each corresponding to a first conveying unit 11, with the etching return spray unit 20 positioned above the corresponding first conveying unit 11. The multiple etching return spray units 20 are used to spray etching return liquid of different concentrations. Along the conveying direction S1 of the solar cell 100, the concentration of the etching return liquid sprayed by the multiple etching return spray units 20 gradually decreases.
[0041] The etching solution used is an acidic etching solution, which may include sulfuric acid and hydrogen peroxide.
[0042] During the etching process, multiple first conveying units 11 serve as the etching spraying section for the solar cell 100. These units sequentially transport the solar cell 100 beneath multiple etching spraying units 20. The solar cell 100 first passes under the etching spraying unit 20 sprayed with the highest concentration etching solution, which erodes the metal seed layer on the surface of the solar cell 100. Subsequently, the solar cell 100 passes under the etching spraying unit 20 sprayed with the second highest concentration etching solution, which also erodes the metal seed layer on the surface of the solar cell 100. This process continues until the solar cell 100 passes under the etching spraying unit 20 sprayed with the lowest concentration etching solution, which continues to erode the metal seed layer on the surface of the solar cell 100.
[0043] The second transport unit 12 is the idle run etching section of the solar cell 100. Upon reaching the second transport unit 12, the concentration of the etching solution remaining on the surface of the solar cell 100 is at its lowest. During the transport of the solar cell 100 by the second transport unit 12, the lowest concentration of etching solution remaining on the surface of the solar cell 100 continues to etch the metal seed layer of the solar cell 100 with a low corrosive ability, so that the metal seed layer is completely removed. After the metal seed layer is completely etched, the lowest concentration of etching solution in contact with the transparent conductive film will not damage the transparent conductive film, until the solar cell 100 reaches the third transport unit 13.
[0044] The third conveying unit 13 is the cleaning section of the solar cell 100. The cleaning spray unit 30 is located above the third conveying unit 13. The cleaning spray unit 30 is used to spray cleaning fluid to clean the residual etching fluid on the surface of the solar cell 100.
[0045] In this embodiment, the solar cell passes through a spray zone with a gradually decreasing concentration of etching solution. The corrosion capacity of the multiple etching processes corresponding to the multiple first conveying units gradually decreases. When the solar cell reaches the second conveying unit, the concentration of etching solution remaining on the surface of the solar cell is relatively low. During the conveying process in the second conveying unit, the etching continues with a lower corrosion capacity. After the metal seed layer is completely etched, the low-concentration etching solution that comes into contact with the transparent conductive film will not damage the transparent conductive film. This ensures the etching effect of the metal seed layer while avoiding damage to the transparent conductive film, thus preventing color difference and efficiency reduction in the solar cell after etching and cleaning, which is beneficial to improving the product yield of the solar cell.
[0046] As one implementation method, Figure 3 This is a schematic diagram of the structure of solar cell 100 before the re-etching and cleaning process; Figure 4 This is a schematic diagram of the structure of the solar cell 100 after the etching and cleaning process; please refer to [link / reference]. Figure 3 and Figure 4As shown, the solar cell 100 can be a heterojunction solar cell (HJT), which includes a silicon substrate 111, a first intrinsic amorphous silicon layer 121 and a second intrinsic amorphous silicon layer 122 respectively stacked on the first surface and the second surface of the silicon substrate 111, an N-type doped amorphous silicon layer 131 stacked on the side of the first intrinsic amorphous silicon layer 121 away from the silicon substrate 111, and a P-type doped amorphous silicon layer 132 stacked on the side of the second intrinsic amorphous silicon layer 122 away from the silicon substrate 111. The silicon substrate 111 is a silicon wafer with textured upper and lower surfaces respectively. During the deposition of transparent conductive films, transparent conductive films 141 are deposited on the side of the N-type doped amorphous silicon layer 131 away from the silicon substrate 111 and on the side of the P-type doped amorphous silicon layer 132 away from the silicon substrate 111, respectively. Subsequently, a first metal seed layer 151 and a second metal seed layer 152 can be deposited on the two transparent conductive films 141 using a PVD magnetron sputtering device, and metal gate electrodes 16 are fabricated on the first metal seed layer 151 and the second metal seed layer 152, respectively, to obtain... Figure 3 The solar cell 100 shown. Exemplarily, the thickness of the first intrinsic amorphous silicon layer 121 can be 3–6 nm, and the thickness of the second intrinsic amorphous silicon layer 122 can be 3–9 nm; the thickness of the N-type doped amorphous silicon layer 131 can be 5–10 nm, and the thickness of the P-type doped amorphous silicon layer 132 can be 5–15 nm. The thicknesses of the first metal seed layer 151 and the second metal seed layer 152 can be 100–250 nm, respectively.
[0047] Then, the solar cell re-etching and cleaning device of this embodiment is used to... Figure 3 After removing the first metal seed layer 151 and the second metal seed layer 152 corresponding to the non-metallic gate line regions shown, for example, we obtain... Figure 4 Please refer to the solar cell 100 shown. Figure 4 As shown, the metal gate electrode 16 includes a metal seed layer 161, a metal gate layer 162, and a protective layer 163 stacked sequentially. For example, the metal seed layer 161 can be a copper seed layer, the metal gate layer 162 can be a copper gate layer, and the protective layer 163 is a tin metal layer. The metal seed layer 161 corresponds to the portion of the first metal seed layer 151 that has not been etched back and cleaned, or corresponds to the portion of the second metal seed layer 152 that has not been etched back and cleaned.
[0048] As one implementation method, please refer to Figure 5 As shown, the spray surface 21a of the etching spray unit 20 is parallel to the upper surface of the solar cell 100. In this embodiment, by setting the spray surface to be parallel to the solar cell, the spray liquid can be in full contact with the solar cell, thereby improving the etching effect.
[0049] As one implementation method, please refer to Figure 6 and Figure 7 As shown, the spray surface 21b of the etch-back spray unit 20 includes a first spray surface 21b1, a second spray surface 21b2, and a third spray surface 21b3 connected in sequence. The second spray surface 21b2 is parallel to the upper surface of the solar cell 100, and the first spray surface 21b1 and the third spray surface 21b3 are arranged obliquely and symmetrically. In this embodiment, the spray surface of the etch-back spray unit is arranged in the above manner, so that the spray range covers the entire solar cell, and the spray liquid is in full contact with the solar cell, thereby improving the etch-back effect.
[0050] As one implementation method, please refer to Figure 8 As shown, the etch-back spray unit 20 includes a first nozzle 21, a first liquid storage tank 22, and a first pipeline 23 for connecting the first nozzle 21 and the first liquid storage tank 22. The first liquid storage tank 22 is used to store the etch-back liquid. Correspondingly, the cleaning spray unit 30 adopts a similar structure to the etch-back spray unit 20. The cleaning spray unit 30 includes a second nozzle, a second liquid storage tank, and a second pipeline for connecting the second nozzle and the second liquid storage tank. The second liquid storage tank is used to store the cleaning liquid.
[0051] As one implementation method, please refer to Figure 9 and Figure 10 As shown, the roller 10a includes a roller 101 and a plurality of rollers 102. The rollers 102 are sleeved on the outside of the roller 101. The roller 101 includes two ends 1011. The plurality of rollers 102 are arranged sequentially along the length direction of the roller 101. The plurality of rollers 102 are arranged sequentially and spaced between the two ends 1011. A notch 103 is formed between each two adjacent rollers 102.
[0052] In the conveying mechanism 10, multiple rollers 10a are arranged in parallel, and the rollers 102 of the multiple rollers 10a are in contact with the lower surface of the solar cell 100. The roller 101 drives the rollers 102 to rotate, carrying the solar cell 100 to move along the conveying direction S1.
[0053] In one implementation, the solar cell re-etching cleaning device includes three re-etching spray units 20.
[0054] As one implementation method, please refer to Figure 11 As shown, the solar cell re-etching cleaning device also includes a re-etching tank 40, and multiple first conveying units 11 are respectively disposed in the re-etching tank 40. The re-etching tank 40 is used to collect the re-etching liquid sprayed by multiple re-etching spraying units 20.
[0055] In some embodiments, the second conveying unit 12 and the third conveying unit 13 are respectively disposed in the return groove 40. The return groove 40 is also used to collect the cleaning fluid sprayed by the cleaning spray unit 30.
[0056] As one implementation method, please refer to Figure 12 As shown, the solar cell re-etching and cleaning device also includes a re-etching tank 40 and a cleaning tank 50. Multiple first conveying units 11 are respectively disposed within the re-etching tank 40, which is used to collect the re-etching liquid sprayed by multiple re-etching spraying units 20. A third conveying unit 13 is disposed within the cleaning tank 50, which is used to collect the cleaning liquid sprayed by the cleaning spraying unit 30.
[0057] As one implementation method, the metal grid lines can be fabricated in the following way:
[0058] Copper plating: Photosensitive emulsion is coated on the first metal seed layer 151 and the second metal seed layer 152 respectively to completely cover the copper seed layer. The thickness of the photosensitive emulsion layer is controlled at 10-15 μm.
[0059] Printing and Exposure: The designed grid pattern is printed onto the photosensitive emulsion layer and exposed. The photosensitive emulsion layer will change when exposed to light (non-grid area is exposed to light), which can be distinguished from the unexposed area (i.e., grid area).
[0060] Development: The unexposed photosensitive emulsion layer (raster area) is cleaned and removed using a sodium carbonate (Na2CO3) solution. The sodium carbonate concentration is controlled at 10-20 g / L, the solution temperature is 25℃-35℃, the nozzle pressure is 0.5 bar-2.5 bar, and the solution pH is controlled between 8 and 13. The sodium carbonate solution reacts with the unexposed photosensitive emulsion layer to form patterned grooves.
[0061] Edge binding: Wrap the four edges and corners with edge binding adhesive. The width of the edge binding adhesive should be less than or equal to 50μm and the thickness should be 10-15μm.
[0062] Electroplating: Copper grid line 162 is electroplated in copper sulfate electroplating solution, with the height of copper grid line 162 controlled at 8-10 μm. Tin grid line 163 is electroplated in tin methanesulfonate electroplating solution, with the height of tin grid line 163 controlled at 2-4 μm.
[0063] Removal: Remove all the edge-sealing adhesive and masking material (photosensitive emulsion layer) in a strongly alkaline solution.
[0064] One embodiment of this application provides a solar cell fabrication system, which includes the solar cell etch-back cleaning device described above.
[0065] In this embodiment, during the etch-back cleaning process of the solar cell, as the concentration of the etch-back liquid sprayed by multiple etch-back spraying units gradually decreases along the transport direction of the solar cell, the solar cell undergoes multiple etch-back processes with gradually decreasing corrosion capacity as the etch-back liquid concentration decreases. When it reaches the second transport unit, the concentration of etch-back liquid remaining on the surface of the solar cell is relatively low. During the transport process in the second transport unit, the etch-back continues with a lower corrosion capacity. After the metal seed layer is completely etched back, the low-concentration etch-back liquid in contact with the transparent conductive film will not damage the transparent conductive film. This ensures the etch-back effect of the metal seed layer while avoiding damage to the transparent conductive film, thus preventing color difference and efficiency reduction in the solar cell after etch-back cleaning, which is beneficial to improving the product yield of the solar cell.
[0066] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0067] The above embodiments merely illustrate preferred implementations of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the appended claims.
Claims
1. A solar cell re-etching and cleaning device, characterized in that, include: The conveying mechanism includes a plurality of first conveying units, second conveying units, and third conveying units arranged sequentially along the conveying direction of the solar cells; the first conveying unit, the second conveying unit, and the third conveying unit each include a plurality of rollers arranged at intervals along the conveying direction of the solar cells. Multiple etch-back spraying units are respectively located above the corresponding first conveying units and are used to spray etch-back liquid of different concentrations. Along the conveying direction of the solar cell, the concentration of the etch-back liquid sprayed by the multiple etch-back spraying units gradually decreases. A cleaning spray unit is provided above the third conveying unit, and the cleaning spray unit is used to spray cleaning liquid.
2. The solar cell re-etching and cleaning device according to claim 1, characterized in that, The spray surface of the etched spray unit is parallel to the upper surface of the solar cell.
3. The solar cell re-etching and cleaning device according to claim 1, characterized in that, The spray surface of the back-etching spray unit includes a first spray surface, a second spray surface and a third spray surface connected in sequence. The second spray surface is parallel to the upper surface of the solar cell, and the first spray surface and the third spray surface are arranged obliquely and symmetrically.
4. The solar cell re-etching and cleaning apparatus according to claim 2 or 3, characterized in that, The back-etching spray unit includes a first nozzle, a first liquid storage tank, and a first pipeline for connecting the first nozzle and the first liquid storage tank. The first liquid storage tank is used to store the back-etching liquid. The cleaning spray unit includes a second nozzle, a second liquid storage tank, and a second pipeline for connecting the second nozzle and the second liquid storage tank, wherein the second liquid storage tank is used to store the cleaning liquid.
5. The solar cell re-etching and cleaning device according to claim 1, characterized in that, The solar cell re-etching cleaning device includes three re-etching spray units.
6. The solar cell re-etching and cleaning device according to claim 1, characterized in that, The solar cell re-etching and cleaning device also includes a re-etching tank, and multiple first conveying units are respectively disposed in the re-etching tank.
7. The solar cell re-etching and cleaning device according to claim 6, characterized in that, The second conveying unit and the third conveying unit are respectively located in the return groove.
8. The solar cell re-etching and cleaning device according to claim 6, characterized in that, The solar cell re-etching and cleaning device also includes a cleaning tank, and the third conveying unit is located in the cleaning tank.
9. The solar cell re-etching and cleaning device according to claim 1, characterized in that, The roller includes a roller shaft and a plurality of rollers sleeved on the roller shaft.
10. A solar cell fabrication system, characterized in that, Includes the solar cell re-etching and cleaning apparatus as described in any one of claims 1 to 9.