Method for manufacturing back contact solar cell with separately manufactured main and fine gate electrodes

Abstract

The invention discloses a manufacturing method of a back contact solar cell with separately manufactured main and fine gate electrodes. The method comprises the following steps: preparing a main gate electrode on a polymer film, chemically tinning to form a tin-coated layer, printing insulating ink on the tin-coated layer at intervals, and curing to form a film main gate electrode unit; preparing a fine gate electrode on the silicon wafer, chemically tinning to form a tin-coated layer, and then isolating an N region and a P region to form a quasi-cell unit containing the fine gate electrode; the thin-film main gate electrode unit is placed on the quasi-cell unit containing the fine gate electrode in an aligned mode, heating and curing are conducted to form the back contact solar cell with the polymer thin film, finally, the polymer thin film on the main gate electrode is etched away through laser, the main gate electrode is exposed, and the back contact solar cell is manufactured. The main fine gate electrode is respectively manufactured on the cell and the polymer film and then combined together, so that a metal material with lower cost can be used, the cost of the cell is greatly reduced, the risk of warping and fragment of the back contact heterojunction cell can be reduced, and the yield of the cell is improved.

Description

Technical Field

[0001] The present invention relates to the field of back-contact solar cells, and in particular to a method for manufacturing a back-contact solar cell in which a main and fine grid electrodes are separated and manufactured. Background Art

[0002] At present, the manufacturing method of back-contact heterojunction solar cells is generally as follows: after the silicon wafer undergoes the back-contact heterojunction solar cell process, the cell precursor for the grid line to be made is formed, and then the silver paste fine grid is printed. At the intersection of the main grid and the fine grid, insulating ink is printed on the positive and negative electrode fine grids in an intermittent manner, and then the silver paste main grid is printed.

[0003] Conventional back-contact heterojunction cells are printed with a silver paste grid on the back of the cell. After the grid is dried, insulating ink is printed. After drying and curing, the silver paste main grid is printed and then dried and cured. This multiple printing process increases the backside load, consumes a lot of silver paste, and is costly. It also creates uneven stress on the front and back sides of the cell, making it prone to warping and breakage. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a method for manufacturing a back-contact solar cell with separated main and fine gate electrodes.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: a method for manufacturing a back-contact solar cell with separated main and fine gate electrodes, the method comprising the following steps:

[0006] S1, depositing a first metal seed layer on the polymer film;

[0007] S2, electroplating to grow a first metal layer;

[0008] S3, filling the first ink layer onto the first metal layer, and forming an ink strip after curing;

[0009] S4, etching the first metal layer and the first metal seed layer not covered by the ink line;

[0010] S5, placing the polymer film forming the main gate electrode in a chemical tin plating solution to form a first tin coating layer;

[0011] S6, intermittently printing insulating ink on the first tin-coated layer to form ink blocks, which are cured to form thin-film main gate electrode units;

[0012] S7, depositing a second metal seed layer on the silicon wafer that has been cleaned and textured, SiNx plated on the front side, amorphous silicon in the N and P regions formed on the back side, and a TCO film deposited on the back side;

[0013] S8, growing a second metal layer by electroplating;

[0014] S9, filling the second ink layer onto the second metal layer, and forming an ink line after curing;

[0015] S10, etching the second metal layer and the second metal seed layer not covered by the ink line, and then removing the ink to form a fine gate electrode;

[0016] S11, placing the fine gate electrode in a chemical tin plating solution to form a second tin coating layer;

[0017] S12, isolating the N region and the P region of the silicon wafer to form a quasi-battery unit with a fine gate electrode;

[0018] S13, aligning the thin film main grid electrode unit to the quasi-cell unit containing the fine grid electrode, centering the ink block on the second tin coating layer, and heating and curing to form a heterojunction back contact solar cell with a polymer thin film;

[0019] S14. Use laser to ablate the polymer film on the main gate electrode to expose the main gate electrode to form a back contact heterojunction solar cell.

[0020] Furthermore, the polymer film is one of PET film, PP film and PI film, and the thickness of the polymer film is 0.001-0.1 mm.

[0021] Furthermore, the first and second metal seed layers are single film layers or composite film layers of copper metal seed layers, nickel metal seed layers, silver metal seed layers, and aluminum metal seed layers, and the deposition method of the metal seed layer is one of PVD sputtering, PVD evaporation, and PVD ion plating, and the deposition thickness is 10-1000nm.

[0022] Furthermore, the electroplating growth of the first metal layer is performed by horizontal electroplating or vertical electroplating, the electroplating current density is 10-20ASD, the electroplating time is 1-60min, the height of the first metal layer is 0.005-0.1mm, and the material of the electroplated electrode grid line is one of copper, nickel, silver, and aluminum.

[0023] Furthermore, the first ink layer filling method is a screen printing method, the ink strip width is 0.1-1mm, the thickness is 0.005-0.02mm, the ink is one of photocurable ink, heat curable ink, and UV curable ink, and the ink curing method is the corresponding photocuring, heat curing, and UV curing.

[0024] Furthermore, the etching solution system is one of an ammonia system, a sulfuric acid-hydrogen peroxide system, and a nitric acid system, the etching solution concentration is 0.1-10 mol / L, and the etching time is 0.5-30 min.

[0025] Furthermore, the concentration of the chemical tin plating solution used for the first and second tin-coating layers is 0.1-1 mol / L, the tin plating time is 1-5 min, and the thickness of the tin coating layer is 0.001-0.01 mm.

[0026] Furthermore, the insulating ink filling method is a screen printing method, the ink block is rectangular, the ink block length is 0.15-1.05mm, the width is greater than the first tin coating layer, the ink block width is 0.055-0.55mm, the width is greater than the second tin coating layer, the ink block thickness is 0.01-0.05mm, the ink is one of thermal curing ink and UV curing ink, and the ink curing method is the corresponding thermal curing or UV curing.

[0027] Furthermore, the electroplating growth of the second metal layer is a horizontal electroplating method or a vertical electroplating method, the electroplating current density is 3-10ASD, the electroplating time is 1-30min, the height of the second metal layer is 0.001-0.01mm, and the material of the electroplated electrode grid line is one of copper, nickel, silver, and aluminum.

[0028] Furthermore, the second ink layer filling method is a screen printing method, the ink line width is 0.05-0.5mm, the thickness is 0.005-0.02mm, the ink is one of photocurable ink, heat curable ink, and UV curable ink, and the ink curing method is the corresponding photocuring, heat curing, and UV curing.

[0029] Furthermore, the isolation method for isolating the N region and the P region of the isolation battery is one of a laser ablation method and a chemical etching method.

[0030] Furthermore, the heating and curing to form a heterojunction back-contact solar cell with a polymer film is performed by hot air heating at a temperature of 80-130° C. for 1-10 minutes.

[0031] Furthermore, the laser used to ablate the polymer film on the main gate electrode is a far-infrared laser with a wavelength of 2500-15000 nm, a laser power density of 0.1-20 W / mm2, a laser spot size of 0.01-0.5 mm, and a laser scribing rate of 1-1000 mm / s.

[0032] It can be seen from the above description of the present invention that, compared with the prior art, the present invention has the following advantages:

[0033] The present invention separates the main fine grid electrodes into the battery and the polymer film and then combines them together. The main fine grid electrodes are all made by electroplating process, which can use low-cost metal materials, greatly reducing battery costs, and reducing the risk of warping and breaking of back-contact heterojunction batteries, thereby improving battery yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0035] Figure 1 This is a schematic structural diagram of steps S1 and S2 of the present invention;

[0036] Figure 2 This is a schematic structural diagram of steps S3 and S4 of the present invention;

[0037] Figure 3 This is a structural diagram of step S5 of the present invention;

[0038] Figure 4 This is a schematic structural diagram of step S6 of the present invention;

[0039] Figure 5 This is a structural diagram of step S7 of the present invention;

[0040] Figure 6 This is a schematic structural diagram of steps S8 and S9 of the present invention;

[0041] Figure 7 This is a structural diagram of step S10 of the present invention;

[0042] Figure 8 This is a structural diagram of step S11 of the present invention;

[0043] Figure 9 This is a structural diagram of step S13 of the present invention;

[0044] Figure 10 Schematic diagram of the structure of step S14 of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0046] Example 1

[0047] refer to Figures 1-10 A method for manufacturing a back-contact solar cell with separated main and fine gate electrodes, the method comprising the following steps:

[0048] S1, depositing a first metal seed layer 11 on a polymer film 10, wherein the polymer film 10 is one of a PET film, a PP film, and a PI film, and the thickness of the polymer film 10 is 0.001-0.1 mm;

[0049] S2. Electroplating a first metal layer 12, using either a horizontal electroplating method or a vertical electroplating method, with an electroplating current density of 10-20 ASD and an electroplating time of 1-60 min. The height of the first metal layer 12 is 0.005-0.1 mm, and the material of the electroplated electrode grid line is one of copper, nickel, silver, and aluminum;

[0050] S3. Filling the first ink layer 13 onto the first metal layer 12 and forming ink strips after curing. The first ink layer 13 is filled by screen printing. The ink strips have a width of 0.1-1 mm and a thickness of 0.005-0.02 mm. The ink is one of light-curing ink, heat-curing ink, and UV-curing ink. The ink curing method is light-curing, heat-curing, or UV-curing.

[0051] S4, etching the first metal layer 12 and the first metal seed layer 11 not covered by the ink line, the etching solution system is one of an ammonia system, a sulfuric acid-hydrogen peroxide system, and a nitric acid system, the etching solution concentration is 0.1-10 mol / L, and the etching time is 0.5-30 min;

[0052] S5, placing the polymer film forming the main gate electrode in a chemical tin plating solution to form a first tin-coated layer 14;

[0053] S6. Insulating ink is intermittently printed on the first tin-coated layer 14 to form ink blocks 15. After curing, thin-film main-gate electrode units are formed. The insulating ink is filled by screen printing. The ink blocks 15 are rectangular, 0.15-1.05 mm long, and wider than the first tin-coated layer. The ink blocks 15 are 0.055-0.55 mm wide, and wider than the second tin-coated layer 24. The ink blocks 15 are 0.01-0.05 mm thick. The ink is one of heat-curing ink and UV-curing ink, and the ink curing method is heat-curing or UV-curing.

[0054] S7, depositing a second metal seed layer 21 on the silicon wafer 20 that has been cleaned and textured, SiNx plated on the front side, amorphous silicon in the N and P regions formed on the back side, and a TCO film deposited on the back side;

[0055] S8. Electroplating grows the second metal layer 22, using either a horizontal electroplating method or a vertical electroplating method, with an electroplating current density of 3-10 ASD and an electroplating time of 1-30 min. The height of the second metal layer 22 is 0.001-0.01 mm, and the material of the electroplated electrode grid line is one of copper, nickel, silver, and aluminum;

[0056] S9. Fill the second metal layer 22 with the second ink layer 23 and form ink lines after curing. The second ink layer 23 is filled by screen printing. The ink line width is 0.05-0.5 mm and the thickness is 0.005-0.02 mm. The ink is one of light-curing ink, heat-curing ink, and UV-curing ink. The ink curing method is light-curing, heat-curing, or UV-curing.

[0057] S10, etching the second metal layer 22 and the second metal seed layer 21 not covered by the ink line, and then removing the ink to form a fine gate electrode;

[0058] S11, placing the fine gate electrode in a chemical tin plating solution to form a second tin-coated layer 24;

[0059] S12, using laser ablation or chemical etching to isolate the N region and the P region of the silicon wafer to form a quasi-battery unit with a fine gate electrode;

[0060] S13, aligning the thin film main grid electrode unit to the quasi-cell unit containing the fine grid electrode, centering the ink block 15 on the second tin-coated layer 24, and heating and curing to form a heterojunction back-contact solar cell with a polymer film, using hot air heating at a temperature of 80-130° C. for 1-10 minutes;

[0061] S14. Use a far-infrared laser with a wavelength of 2500-15000nm, a laser power density of 0.1-20W / mm2, a laser spot size of 0.01-0.5mm, and a laser scratching rate of 1-1000mm / s to ablate the polymer film 10 on the main gate electrode to expose the main gate electrode to form a back-contact heterojunction solar cell. The laser used is.

[0062] The first and second metal seed layers 11 / 21 are single film layers or composite film layers of copper metal seed layers, nickel metal seed layers, silver metal seed layers, and aluminum metal seed layers. The deposition method of the metal seed layer is one of PVD sputtering, PVD evaporation, and PVD ion plating, and the deposition thickness is 10-1000nm.

[0063] The concentration of the chemical tin plating solution used in the first and second tin-coating layers 14 / 24 is 0.1-1 mol / L, the tin plating time is 1-5 minutes, and the thickness of the tin coating layer is 0.001-0.01 mm.

[0064] Example 2

[0065] The method of Example 1 is followed, except that a busbar and fine gate are fabricated on the polymer film 10, and then an insulating ink block is fabricated to form a thin-film busbar and fine gate electrode unit, which is then combined with a back-contact heterojunction cell with NP isolation.

[0066] The present invention separates the main fine grid electrodes into the battery and the polymer film and then combines them together. The main fine grid electrodes are all made by electroplating process, which can use low-cost metal materials, greatly reducing battery costs, and reducing the risk of warping and breaking of back-contact heterojunction batteries, thereby improving battery yield.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for manufacturing a back-contact solar cell with separated main and fine gate electrodes, characterized by: The method comprises the following steps: S1, depositing a first metal seed layer on the polymer film; S2, electroplating to grow a first metal layer; S3, filling the first ink layer onto the first metal layer, and forming an ink strip after curing; S4, etching the first metal layer and the first metal seed layer not covered by the ink line; S5, placing the polymer film forming the main gate electrode in a chemical tin plating solution to form a first tin coating layer; S6, intermittently printing insulating ink on the first tin-coated layer to form ink blocks, which are cured to form thin-film main gate electrode units; S7, depositing a second metal seed layer on the silicon wafer that has been cleaned and textured, SiNx plated on the front side, amorphous silicon in the N and P regions formed on the back side, and a TCO film deposited on the back side; S8, growing a second metal layer by electroplating; S9, filling the second ink layer onto the second metal layer, and forming an ink line after curing; S10, etching the second metal layer and the second metal seed layer not covered by the ink line, and then removing the ink to form a fine gate electrode; S11, placing the fine gate electrode in a chemical tin plating solution to form a second tin coating layer; S12, isolating the N region and the P region of the silicon wafer to form a quasi-battery unit with a fine gate electrode; S13, aligning the thin film main grid electrode unit to the quasi-cell unit containing the fine grid electrode, centering the ink block on the second tin coating layer, and heating and curing to form a heterojunction back contact solar cell with a polymer thin film; S14. Use laser to ablate the polymer film on the main gate electrode to expose the main gate electrode to form a back contact heterojunction solar cell.

2. The method for manufacturing a back-contact solar cell with separated main and fine gate electrodes according to claim 1, characterized in that: The polymer film is one of a PET film, a PP film, and a PI film, and the thickness of the polymer film is 0.001-0.1 mm.

3. The method for manufacturing a back-contact solar cell with separated main and fine gate electrodes according to claim 1, characterized in that: The first and second metal seed layers are single film layers or composite film layers of copper metal seed layer, nickel metal seed layer, silver metal seed layer, and aluminum metal seed layer. The deposition method of the metal seed layer is one of PVD sputtering, PVD evaporation, and PVD ion plating, and the deposition thickness is 10-1000nm.

4. The method for manufacturing a back-contact solar cell with separated main and fine gate electrodes according to claim 1, characterized in that: The electroplating growth of the first metal layer is performed by horizontal electroplating or vertical electroplating, the electroplating current density is 10-20ASD, the electroplating time is 1-60min, the height of the first metal layer is 0.005-0.1mm, and the material of the electroplated electrode grid line is one of copper, nickel, silver, and aluminum.

5. The method for manufacturing a back-contact solar cell with separated main and fine gate electrodes according to claim 1, characterized in that: The first ink layer filling method is a screen printing method, the ink strip width is 0.1-1mm, the thickness is 0.005-0.02mm, the ink is one of photocurable ink, heat curable ink, and UV curable ink, and the ink curing method is the corresponding photocuring, heat curing, and UV curing.

6. The method for manufacturing a back-contact solar cell with separated main and fine gate electrodes according to claim 1, characterized in that: The etching solution system is one of an ammonia system, a sulfuric acid-hydrogen peroxide system, and a nitric acid system. The etching solution concentration is 0.1-10 mol / L, and the etching time is 0.5-30 min.

7. The method for manufacturing a back-contact solar cell with separated main and fine gate electrodes according to claim 1, characterized in that: The concentration of the chemical tin plating solution used for the first and second tin-coating layers is 0.1-1 mol / L, the tin plating time is 1-5 minutes, and the thickness of the tin coating layer is 0.001-0.01 mm.

8. The method for manufacturing a back-contact solar cell with separated main and fine gate electrodes according to claim 1, characterized in that: The insulating ink filling method is a screen printing method, the ink block is rectangular, the ink block length is 0.15-1.05 mm, the width is greater than the first tin coating layer, the ink block width is 0.055-0.55 mm, the width is greater than the second tin coating layer, the ink block thickness is 0.01-0.05 mm, the ink is one of thermal curing ink and UV curing ink, and the ink curing method is the corresponding thermal curing or UV curing.

9. The method for manufacturing a back-contact solar cell with separated main and fine gate electrodes according to claim 1, characterized in that: The electroplating growth of the second metal layer is performed by horizontal electroplating or vertical electroplating, the electroplating current density is 3-10ASD, the electroplating time is 1-30min, the height of the second metal layer is 0.001-0.01mm, and the material of the electroplated electrode grid line is one of copper, nickel, silver, and aluminum.

10. The method for manufacturing a back-contact solar cell with separated main and fine gate electrodes according to claim 1, characterized in that: The second ink layer filling method is a screen printing method, the ink line width is 0.05-0.5mm, the thickness is 0.005-0.02mm, the ink is one of photocurable ink, heat curable ink, and UV curable ink, and the ink curing method is the corresponding photocuring, heat curing, and UV curing.

11. The method for manufacturing a back-contact solar cell with separated main and fine gate electrodes according to claim 1, characterized in that: The isolation method of the N region and the P region of the isolation battery is one of a laser ablation method and a chemical etching method.

12. The method for manufacturing a back-contact solar cell with separated main and fine gate electrodes according to claim 1, characterized in that: The heating and curing forms a heterojunction back-contact solar cell with a polymer film, and the heating method is hot air heating, the temperature is 80-130° C., and the time is 1-10 minutes.

13. The method for manufacturing a back-contact solar cell with separated main and fine gate electrodes according to claim 1, characterized in that: The laser used to ablate the polymer film on the main grid electrode is a far-infrared laser with a wavelength of 2500-15000nm, a laser power density of 0.1-20W / mm2, a laser spot size of 0.01-0.5mm, and a laser scribing rate of 1-1000mm / s.

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