A laser-cut full-open steel plate and a preparation process thereof

Abstract

The application belongs to the technical field of electrode printing, and specifically provides a laser-cut full-opening steel plate and a preparation process thereof. The laser-cut full-opening steel plate comprises a nickel sheet base, a Ni-W-P interface layer and a polyimide film; the Ni-W-P interface layer and the polyimide film are arranged on at least one side of the nickel sheet base. The laser-cut full-opening steel plate prepared by the application can meet the printing scene of different grid line structures, and has a wide application range.

Description

Technical Field

[0001] This application belongs to the field of electrode printing technology, and in particular relates to a laser-cut fully open steel plate and its preparation process. Background Technology

[0002] With the development of high-efficiency photovoltaic cell technologies such as PERC, TOPCon, and HJT, the width of the cell grid lines in the photovoltaic cell metallization process is constantly decreasing. This places higher demands on the screen printing process regarding the accuracy of the stencil opening size, edge integrity, dimensional consistency, and long-term service stability. Full-aperture stencils, due to their ability to effectively reduce paste resistance, improve paste transfer efficiency, and enhance the forming quality of fine grid lines, are gradually becoming an important development direction for high-precision screen printing. Current laser-cut full-aperture stencils typically employ a hot-pressing method to laminate a polyimide protective film to a nickel-steel plate before laser cutting, thus balancing stencil processing accuracy, mechanical strength, and printing stability.

[0003] However, the bonding between metal and polyimide mainly relies on interfacial polarity. At the same time, the composition, uniformity, and interfacial chemical state of the natural oxide film on the nickel surface also directly affect the interfacial bonding. During long-term thermal cycling or service, oxygen diffusion may occur in the interfacial area, leading to polyimide degradation and a decrease in interfacial bonding force. This results in local peeling of the protective film, decreased dimensional stability, and reduced processing accuracy.

[0004] To address these issues, methods such as increasing hot-pressing pressure, extending hot-pressing time, and plasma activation treatment of the polyimide surface can be used to improve interfacial bonding performance. However, increasing hot-pressing parameters can increase the risk of thermal aging of the polyimide, and activation of only the polyimide may lead to a decline in its long-term service effectiveness. Summary of the Invention

[0005] To address the aforementioned issues and further improve the interfacial bonding performance between polyimide and nickel steel plate, this application provides a laser-cut fully open steel plate and its preparation process.

[0006] This application first provides a laser-cut fully open steel plate, including a nickel sheet substrate, a Ni-WP interface layer and a polyimide film; the Ni-WP interface layer and the polyimide film are disposed on at least one side of the nickel sheet substrate.

[0007] Furthermore, the Ni-WP interface layer and the polyimide film are disposed symmetrically on the printing surface or the paste injection surface of the nickel substrate.

[0008] Furthermore, this application provides a method for preparing a laser-cut fully open steel plate, comprising the following steps: S1, hot-pressing a modified polyimide film and a modified nickel sheet together; S2, fixing the composite nickel sheet onto a support frame and applying a preset tension; S3, using a laser to cut at least two layers of the nickel sheet substrate along a preset trajectory to form a stepped opening structure; S4, laser processing the polyimide film to form a protective structure aligned with the opening of the nickel sheet, and performing post-processing on the finished product.

[0009] Furthermore, in S1, the method for preparing the modified nickel sheet includes the following steps: A1, pretreating the surface of the nickel sheet substrate to prepare a Ni-WP interface layer and performing activation treatment; A2, immersing the activated nickel sheet substrate in a silane coupling agent solution for silanization treatment to obtain the modified nickel sheet.

[0010] Furthermore, in S1, the method for preparing the modified polyimide film includes the following steps: the polyimide film is ultrasonically cleaned and then immersed in NaOH solution for modification to obtain the modified polyimide film.

[0011] Furthermore, in S3, the laser is an ultraviolet picosecond laser or a femtosecond laser, and the laser cutting parameters are: power 6-10W, pulse frequency 80-120kHz, scanning speed 400-600mm / s, and the number of single-layer repeated cuttings is 10-15 times; when cutting the next layer, the laser focus position automatically moves down relative to the previous layer, and the amount of downward movement is determined according to the thickness of the already cut layer.

[0012] Furthermore, in S4, the post-processing involves plasma cleaning with an Ar / O2 mixed gas followed by stress relief treatment in a vacuum oven.

[0013] Furthermore, in A1, the pretreatment involves sequentially degreasing and acid-washing the nickel substrate, followed by placing it in a plating solution to prepare a Ni-WP interface layer; the activation treatment is oxygen plasma treatment.

[0014] Furthermore, the plating solution contains the following components at the following mass concentrations: NiSO4 20-30 g / L, Na2WO4 15-25 g / L, Na3C6H5O7 40-50 g / L, NaH2PO2 15-25 g / L, pH value 8.5-9.5, plating temperature 88-95℃, and plating time 1-3 h.

[0015] Furthermore, this application provides an application of laser-cut fully open steel plates for electrode printing in HJT batteries, BC batteries, or Topcon batteries.

[0016] Compared with the prior art, this application has the following beneficial effects: 1. After activation, the Ni-WP interface layer in the modified nickel sheet achieves chemical bonding with the modified polyimide film through a silane coupling agent. At the same time, the Ni-WP interface layer can play a role in wear resistance, corrosion resistance and laser processing stability, thereby synergistically improving the interface bonding performance and the service performance of the steel sheet.

[0017] 2. This application provides a variety of customized steel plate structures to meet the differentiated printing needs of HJT and BC / Topcon batteries. It can simultaneously meet the printing scenarios of different grid structures such as disconnected and fully through-type, and has a wide range of applications. By combining laser cutting with polyimide film grooving and protective layer reinforcement processes, it solves the problems of burrs, thermal deformation and poor wear resistance that exist in the single laser cutting process, and forms a complete set of fully open steel plate preparation process. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the cross-section of the laser-cut multi-layer fully open steel grid line of this application, where Ni is nickel sheet and PI is polyimide. Detailed Implementation

[0019] To make the inventive objectives, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. Obviously, the described embodiments are only a portion of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0020] 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. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] When using “including,” “having,” and “contains” as described herein, the intention is to cover non-exclusive inclusion, unless an explicit qualifying term such as “only” is used, in which case another component may be added.

[0022] In this application, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise explicitly specified. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0023] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0024] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method comprising steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0025] The present application will be further illustrated by the following examples, but these examples do not limit the scope of the present application.

[0026] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this application, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description in this application, any prior art methods, equipment, and materials similar to or equivalent to those described, used, or made by the methods, equipment, and materials in the embodiments of this application may be used to implement this application.

[0027] Example 1 The method for preparing the laser-cut fully open steel plate in this embodiment is as follows: S1. A 5μm modified polyimide film is hot-pressed onto a modified nickel sheet. The modified polyimide film is adhered to the P-side (printed side) of the nickel sheet. The hot-pressing temperature is 120℃ and the hot-pressing pressure is 5MPa. After hot-pressing for 20 minutes, the pressure is released and the film is removed and cooled to room temperature.

[0028] S2, fix the composite nickel sheet to the dummy frame with a tension of 15 N / cm.

[0029] S3 uses a UV picosecond laser (wavelength 355nm, pulse width 8ps), with the focus aligned with the S-side of the nickel sheet. Parameters: power 6W, frequency 80kHz, speed 400mm / s, repeated cutting 10 times to form a storage tank; automatically lower the focus by 5μm, adjust parameters to power 5W, frequency 80kHz, speed 400mm / s, repeated cutting 8 times, penetrating the nickel sheet, with an opening line width of 10μm.

[0030] S4. Position the nickel sheet opening using a CCD, adjust the focus to the polyimide film surface, and cut the polyimide film from the P side to form a protective groove. Parameters: power 3W, frequency 120kHz, speed 600mm / s, repeat twice, and finally perform plasma cleaning (Ar / O2=4:1, 100W, 3min), followed by stress release in a vacuum oven (90℃, 1.5h).

[0031] The modified nickel sheet in this embodiment is prepared as follows: A1, a nickel substrate (18μm) was degreased in a dilute NaOH solution at 40℃ for 10 min, rinsed in deionized water for 10 min, and then activated in an HCl solution (50wt%) at 40℃ for 5 min. After rinsing with deionized water, the substrate was placed in a plating solution composed of NiSO4 (20g / L), Na2WO4 (15g / L), Na3C6H5O7 (40g / L), and NaH2PO2 (25g / L), with a pH of 8.5. The solution was kept at 88℃ for 1 h to obtain a Ni-WP interface layer with a thickness of 2μm. Subsequently, oxygen plasma treatment was performed at a power of 50W, a vacuum degree of 10Torr, and a treatment time of 2 min to obtain an activated nickel sheet.

[0032] A2. The activated nickel sheet was immersed in a 2wt% solution of 3-(2-aminoethylamino)propyltriethoxysilane for 3 minutes. After immersion, it was rinsed with ethanol and ultrapure water in sequence and dried with nitrogen to obtain the modified nickel sheet.

[0033] The modified polyimide film in this embodiment is prepared as follows: The polyimide membrane was ultrasonically cleaned in ethanol for 15 min, ultrasonically cleaned in ultrapure water for 15 min, dried with nitrogen, and then immersed in 5 wt% NaOH aqueous solution for 10 min. After removal, it was rinsed with ultrapure water and dried with nitrogen to obtain the modified polyimide membrane.

[0034] Example 2 The method for preparing the laser-cut fully open steel plate in this embodiment is as follows: S1, hot-press a 5μm modified polyimide film with a modified nickel sheet. The modified polyimide film is attached to the S side (slurry inlet side) of the nickel sheet. The hot-pressing temperature is 120℃ and the hot-pressing pressure is 5MPa. After hot-pressing for 20 minutes, the pressure is released and the film is taken out and cooled to room temperature.

[0035] S2, fix the composite nickel sheet to the dummy frame with a tension of 16 N / cm.

[0036] S3 uses a UV femtosecond laser (wavelength 355nm, pulse width 8ps), with the focus aligned with the S-side of the nickel sheet. Parameters: power 8W, frequency 120kHz, speed 500mm / s, repeated 12 times to form a storage tank; automatically lower the focus by 5μm, adjust parameters to power 7W, frequency 120kHz, speed 500mm / s, repeated 10 times, penetrating the nickel sheet, with an opening linewidth of 8μm.

[0037] S4, a 2.5 μm thick nickel layer was deposited on the P-side by magnetron sputtering with a sputtering power of 1.5 kW, an Ar flow rate of 50 sccm, a substrate temperature of 120 °C, a deposition rate of 0.5 μm / min, and a hardness of 250 HV. Finally, it was subjected to plasma cleaning (Ar / O2=4:1, 100 W, 3 min) and stress release in a vacuum oven (90 °C, 1.5 h).

[0038] The modified nickel sheet in this embodiment is prepared as follows: A1, a nickel substrate (16μm) was degreased in a dilute NaOH solution at 40℃ for 10 min, rinsed in deionized water for 10 min, and then activated in an HCl solution (50wt%) at 40℃ for 5 min. After rinsing with deionized water, the substrate was placed in a plating bath composed of NiSO4 (30g / L), Na2WO4 (25g / L), Na3C6H5O7 (50g / L), and NaH2PO2 (15g / L), with a pH of 9.5. The plating was carried out at 95℃ for 2 h to obtain a Ni-WP interface layer with a thickness of 2μm. Subsequently, oxygen plasma treatment was performed at a power of 50W, a vacuum degree of 10Torr, and a treatment time of 2 min to obtain an activated nickel sheet.

[0039] A2. The activated nickel sheet was immersed in a 2wt% solution of 3-(2-aminoethylamino)propyltriethoxysilane for 3 minutes. After immersion, it was rinsed with ethanol and ultrapure water in sequence and dried with nitrogen to obtain the modified nickel sheet.

[0040] The modified polyimide film in this embodiment is prepared as follows: The polyimide membrane was ultrasonically cleaned in ethanol for 15 min, ultrasonically cleaned in ultrapure water for 15 min, dried with nitrogen, and then immersed in 5 wt% NaOH aqueous solution for 10 min. After removal, it was rinsed with ultrapure water and dried with nitrogen to obtain the modified polyimide membrane.

[0041] Example 3 The method for preparing the laser-cut fully open steel plate in this embodiment is as follows: S1. A 5μm modified polyimide film is hot-pressed onto a modified nickel sheet. The modified polyimide film is bonded to the S and P sides of the nickel sheet. The hot-pressing temperature is 120℃ and the hot-pressing pressure is 5MPa. After hot-pressing for 20 minutes, the pressure is released and the film is removed and cooled to room temperature.

[0042] S2, fix the composite nickel sheet to the dummy frame with a tension of 14 N / cm.

[0043] S3 uses a UV picosecond laser (wavelength 355nm, pulse width 8ps), focusing on the S-side of the nickel sheet (which needs to penetrate the S-side PI film). Parameters: power 10W, frequency 150kHz, speed 600mm / s, repeated 15 times; automatically lower the focus by 7μm, adjust parameters to power 9W, frequency 150kHz, speed 600mm / s, repeated 12 times, cutting through the nickel sheet and the S-side polyimide film to form the main grid line opening with a linewidth of 9.5μm.

[0044] S4. Keeping the workpiece position unchanged, adjust the focus to the surface of the polyimide film on the P side, cut the polyimide film on the P side along the gradient connection line trajectory to form a groove structure (width 8μm, depth 5μm), and finally perform plasma cleaning (Ar / O2=4:1, 100W, 3min) and stress release in a vacuum oven (90℃, 1.5h).

[0045] The modified nickel sheet in this embodiment is prepared as follows: A1, a nickel substrate (12μm) was degreased in a dilute NaOH solution at 40℃ for 10 min, rinsed in deionized water for 10 min, and then activated in an HCl solution (50wt%) at 40℃ for 5 min. After rinsing with deionized water, the substrate was placed in a plating solution composed of NiSO4 (25g / L), Na2WO4 (20g / L), Na3C6H5O7 (45g / L), and NaH2PO2 (20g / L), with a pH of 9. The solution was maintained at 92℃ for 2 h to obtain a Ni-WP interface layer with a thickness of 2μm. Subsequently, oxygen plasma treatment was performed at a power of 50W, a vacuum degree of 10Torr, and a treatment time of 2 min to obtain an activated nickel sheet.

[0046] A2. The activated nickel sheet was immersed in a 2wt% solution of 3-(2-aminoethylamino)propyltriethoxysilane for 3 minutes. After immersion, it was rinsed with ethanol and ultrapure water in sequence and dried with nitrogen to obtain the modified nickel sheet.

[0047] The modified polyimide film in this embodiment is prepared as follows: The polyimide membrane was ultrasonically cleaned in ethanol for 15 min, ultrasonically cleaned in ultrapure water for 15 min, dried with nitrogen, and then immersed in 5 wt% NaOH aqueous solution for 10 min. After removal, it was rinsed with ultrapure water and dried with nitrogen to obtain the modified polyimide membrane.

[0048] Comparative Example 1 The method for preparing the laser-cut fully open steel plate in this comparative example is as follows: S1. A 5μm modified polyimide film is hot-pressed onto a modified nickel sheet. The modified polyimide film is bonded to the S and P sides of the nickel sheet. The hot-pressing temperature is 120℃ and the hot-pressing pressure is 5MPa. After hot-pressing for 20 minutes, the pressure is released and the film is removed and cooled to room temperature.

[0049] S2, fix the composite nickel sheet to the dummy frame with a tension of 14 N / cm.

[0050] S3 uses a UV picosecond laser (wavelength 355nm, pulse width 8ps), focusing on the S-side of the nickel sheet (which needs to penetrate the S-side PI film). Parameters: power 10W, frequency 150kHz, speed 600mm / s, repeated 15 times; automatically lower the focus by 7μm, adjust parameters to power 9W, frequency 150kHz, speed 600mm / s, repeated 12 times, cutting through the nickel sheet and the S-side polyimide film to form the main grid line opening with a linewidth of 9.5μm.

[0051] S4. Keeping the workpiece position unchanged, adjust the focus to the surface of the polyimide film on the P side, cut the polyimide film on the P side along the gradient connection line trajectory to form a groove structure (width 8μm, depth 5μm), and finally perform plasma cleaning (Ar / O2=4:1, 100W, 3min) and stress release in a vacuum oven (90℃, 1.5h).

[0052] The modified nickel sheet in this comparative example was prepared as follows: The nickel sheet substrate (12 μm) was degreased in a dilute NaOH solution at 40-50℃ for 10 min, rinsed in deionized water for 10 min, activated in HCl solution (50 wt%) at 40℃ for 5 min, rinsed in deionized water, and then placed in a plating solution composed of NiSO4 (25 g / L), Na2WO4 (20 g / L), Na3C6H5O7 (45 g / L) and NaH2PO2 (20 g / L) with a pH of 9. The solution was kept at 92℃ for 2 h to obtain a Ni-WP interface layer with a thickness of 2 μm. Subsequently, oxygen plasma treatment was performed with a power of 50 W, a vacuum degree of 10 Torr, and a treatment time of 2 min to obtain the modified nickel sheet.

[0053] The modified polyimide film in this comparative example is prepared by the following method: The polyimide membrane was ultrasonically cleaned in ethanol for 15 min, ultrasonically cleaned in ultrapure water for 15 min, dried with nitrogen, and then immersed in 5 wt% NaOH aqueous solution for 10 min. After removal, it was rinsed with ultrapure water and dried with nitrogen to obtain the modified polyimide membrane.

[0054] Comparative Example 2 The method for preparing the laser-cut fully open steel plate in this comparative example is as follows: S1. A 5μm polyimide film is hot-pressed onto a nickel sheet. The polyimide film is adhered to the S and P sides of the nickel sheet. The hot-pressing temperature is 120℃ and the hot-pressing pressure is 5MPa. After hot-pressing for 20 minutes, the pressure is released and the film is removed and cooled to room temperature.

[0055] S2, fix the composite nickel sheet to the dummy frame with a tension of 14 N / cm.

[0056] S3 uses a UV picosecond laser (wavelength 355nm, pulse width 8ps), focusing on the S-side of the nickel sheet (which needs to penetrate the S-side PI film). Parameters: power 10W, frequency 150kHz, speed 600mm / s, repeated 15 times; automatically lower the focus by 7μm, adjust parameters to power 9W, frequency 150kHz, speed 600mm / s, repeated 12 times, cutting through the nickel sheet and the S-side polyimide film to form the main grid line opening with a linewidth of 9.5μm.

[0057] S4. Keeping the workpiece position unchanged, adjust the focus to the surface of the polyimide film on the P side, cut the polyimide film on the P side along the gradient connection line trajectory to form a groove structure (width 8μm, depth 5μm), and finally perform plasma cleaning (Ar / O2=4:1, 100W, 3min) and stress release in a vacuum oven (90℃, 1.5h).

[0058] Performance testing Opening linewidth accuracy: Tested according to standard SJ / T 11759-2020 "Measurement of Aspect Ratio of Photovoltaic Cell Electrode Grid Lines - Laser Scanning Confocal Microscopy Method"; Peel strength: Tested according to GB / T 2790-1995 for the peel strength of the interface between the nickel sheet and the polyimide film; Printing node rate: The prepared steel plate is placed on a photovoltaic cell screen printing machine, and printing tests are performed using standard photovoltaic silver paste. During continuous printing, no less than 100 printed products are randomly selected. The printed grid lines of each cell are fully inspected using optical automatic inspection equipment or a high-magnification microscope. The number of cells with printing defects such as broken grids, incomplete printing, connected grids, and gaps is counted. Node rate = (Number of defective cells / Total number of inspected cells) × 100%.

[0059] Table 1. Performance test results of the fully open steel plates in Examples 1-3 and Comparative Examples 1-2 Analyze Examples 1-3 and Comparative Examples 1-3, in conjunction with Table 1 and Figure 1 As can be seen, this application deposits a Ni-WP interface layer on the surface of a nickel sheet, combines oxygen plasma activation and grafting of silane coupling agent, and covalently bonds it with an alkaline hydrolysis modified polyimide film. At the same time, the Ni-WP interface layer can exert wear resistance and corrosion resistance, significantly improving the interface bonding strength, printing accuracy and long-term service stability of the steel plate.

[0060] Analyzing Table 1, the fully open steel plate prepared in Comparative Example 1, compared to Examples 1-3, although a Ni-WP interface layer was prepared on the nickel sheet surface and activated by oxygen plasma, it was not silanized. The surface of the Ni-WP interface layer lacked grafted amino groups and could not covalently bond with the modified polyimide film, resulting in a significant reduction in interfacial bonding strength. Consequently, the peel strength of the fully open steel plate in Comparative Example 1 decreased, and the printing knot rate increased. In Comparative Example 2, the fully open steel plate, compared to Examples 1-3, did not undergo alkaline hydrolysis surface modification of the polyimide film, nor was the nickel sheet coated or silane modified. The bonding strength between the two decreased significantly, leading to a significant increase in interlayer alignment error and a significant decrease in peel strength.

[0061] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A laser-cut fully open steel plate, characterized in that, Includes a nickel substrate, a Ni-WP interface layer, and a polyimide film; The Ni-WP interface layer and the polyimide film are disposed on at least one side of the nickel sheet substrate.

2. The laser-cut fully open steel plate according to claim 1, characterized in that, The Ni-WP interface layer and polyimide film are disposed on the printing surface or the slurry inlet surface of the nickel substrate, or symmetrically on both sides.

3. A method for preparing a laser-cut fully open steel plate as described in any one of claims 1-2, characterized in that, The process includes the following steps: S1, hot-pressing the modified polyimide film and the modified nickel sheet together; S2, fixing the composite nickel sheet onto a support frame and applying a preset tension; S3, using a laser to cut at least two layers of the nickel sheet substrate along a preset trajectory to form a stepped opening structure; S4, laser processing the polyimide film to form a protective structure aligned with the opening of the nickel sheet, and performing post-processing on the finished product.

4. The method for preparing a laser-cut fully open steel plate according to claim 3, characterized in that, In S1, the method for preparing the modified nickel sheet includes the following steps: A1, pretreating the surface of the nickel sheet substrate to prepare a Ni-WP interface layer and performing activation treatment; A2, immersing the activated nickel sheet substrate in a silane coupling agent solution for silanization treatment to obtain the modified nickel sheet.

5. The method for preparing a laser-cut fully open steel plate according to claim 3, characterized in that, In step S1, the method for preparing the modified polyimide film includes the following steps: the polyimide film is ultrasonically cleaned and then immersed in NaOH solution for modification to obtain the modified polyimide film.

6. The method for preparing a laser-cut fully open steel plate according to claim 3, characterized in that, In S3, the laser is an ultraviolet picosecond laser or a femtosecond laser, and the laser cutting parameters are: power 6-10W, pulse frequency 80-120kHz, scanning speed 400-600mm / s, and the number of single-layer repeated cuttings is 10-15 times; when cutting the next layer, the laser focus position automatically moves down relative to the previous layer, and the amount of downward movement is determined according to the thickness of the already cut layer.

7. The method for preparing a laser-cut fully open steel plate according to claim 3, characterized in that, In step S4, the post-treatment involves plasma cleaning with an Ar / O2 mixed gas followed by stress relief treatment in a vacuum oven.

8. The method for preparing a laser-cut fully open steel plate according to claim 4, characterized in that, In A1, the pretreatment involves sequentially degreasing and acid-washing the nickel substrate, followed by placing it in a plating solution to prepare a Ni-WP interface layer; the activation treatment is oxygen plasma treatment.

9. The method for preparing a laser-cut fully open steel plate according to claim 8, characterized in that, The plating solution contains the following components at the following mass concentrations: NiSO4 20-30 g / L, Na2WO4 15-25 g / L, Na3C6H5O7 40-50 g / L, NaH2PO2 15-25 g / L, pH value 8.5-9.5, plating temperature 88-95℃, and plating time 1-3 h.

10. An application of laser cutting of fully open steel plates, characterized in that, The laser-cut fully open steel plate according to any one of claims 1-2 is used for electrode printing of HJT batteries, BC batteries or Topcon batteries.

Images