A chemical nickel removal method for TOPCon battery and a preparation method for TOPCon battery

Abstract

The present invention provides a chemical nickel removal method for a TOPCon battery and a preparation method for a TOPCon battery, and relates to the technical field of solar cells. The chemical nickel removal method comprises the following steps: chemically removing nickel from a TOPCon solar cell using a nickel removal agent, wherein nickel ions are added to the nickel removal agent. The chemical nickel removal method can reduce the oxidation of the silicon base by the nickel removal agent during the nickel removal process of the TOPCon solar cell, thereby improving the photoelectric conversion efficiency of the TOPCon solar cell and the bonding strength of the metal grid electrode, and can reduce energy loss, thereby achieving the purpose of reducing costs and increasing efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of solar cells, and in particular to a chemical nickel removal method for a TOPCon cell and a preparation method for the TOPCon cell. Background Art

[0002] Metallization is one of the key processes for photovoltaic cells. It is mainly used to make photovoltaic cell electrodes, form ohmic contacts at both ends of the PN junction, and realize current output. Currently, the most commonly used metallization process is still the silver paste screen printing process, which is expensive and difficult to improve the aspect ratio of the grid line. Compared with silver paste screen printing, double-sided copper plating has the advantages of strong conductivity, low contact ohm, low cost and simultaneous double-sided plating.

[0003] At present, the preparation process of double-sided electroplated copper on solar cells requires electroplating nickel on the silicon substrate to prevent copper ions from entering the solar cell and destroying the PN junction. However, the interaction between nickel and silicon makes it difficult to give the metal grid lines of the solar cell excellent bonding strength. The interaction between nickel and silicon can be improved by sintering the nickel and silicon deposited on the solar cell to form a silicon-nickel alloy, and then plating nickel again. However, due to the inconsistency of the thermal expansion coefficients of silicon and nickel, it is necessary to remove the nickel after sintering, and then electroplating nickel, copper, and tin on the substrate again to achieve current output.

[0004] At present, there are two methods of nickel removal: chemical nickel removal and electrolytic nickel removal. Chemical nickel removal usually uses a heated low-concentration solution system and a low-temperature high-concentration solution system; heating will cause the solution to volatilize and decompose, while high concentration will bring cost and safety issues. Electrolytic nickel removal only supports single-sided nickel removal, and the other side is easily corroded by the solution.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] One of the purposes of the present invention is to provide a chemical nickel removal method for TOPCon cells, comprising the following steps: chemically removing nickel from TOPCon solar cells using a nickel removal agent, wherein nickel ions are added to the nickel removal agent. The chemical nickel removal method can reduce the oxidation of the silicon base by the nickel removal agent during the nickel removal process of the TOPCon solar cell, thereby improving the photoelectric conversion efficiency of the TOPCon solar cell and the bonding strength of the metal grid electrode, and can reduce energy loss, thereby achieving the purpose of reducing costs and increasing efficiency.

[0007] The second object of the present invention is to provide a method for preparing a TOPCon battery. The chemical nickel removal step in the preparation method adopts the above-mentioned chemical nickel removal method. The TOPCon battery prepared by the preparation method has higher photoelectric conversion efficiency and stronger bonding force of the metal grid electrode.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0009] In a first aspect, the present invention provides a method for chemical nickel removal of a TOPCon cell, comprising the following steps: chemical nickel removal of a TOPCon solar cell using a nickel removal agent, wherein nickel ions are added to the nickel removal agent.

[0010] In the present invention, by adding nickel ions into the nickel removal agent, the nickel removal rate can be slowed down and the oxidation of the substrate by the nickel removal agent can be reduced.

[0011] Preferably, the chemical nickel removal comprises: inserting the annealed battery cell into a flower basket, immersing it in a bubbling nickel removal tank, and then washing and drying it in sequence after placing it;

[0012] Preferably, the nickel removal agent includes at least one of a mixture of sulfuric acid and hydrogen peroxide, sulfuric acid, and nitric acid;

[0013] Preferably, the nickel removal temperature is 20-25°C, for example, it can be 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, etc.

[0014] Preferably, the chemical nickel removal time is 5-10 minutes.

[0015] Preferably, the nickel removal agent is a mixture of sulfuric acid and hydrogen peroxide;

[0016] Preferably, the ratio of sulfuric acid to hydrogen peroxide is 100-150 ml / L / 100-200 ml / L.

[0017] In the present invention, when sulfuric acid and hydrogen peroxide are used to remove nickel, the reactions include: Ni+H2O2=NiO+H2O, NiO+H2SO4=NiSO4+H2O, wherein when the nickel layer on the surface of the cell falls off, the silicon base will be exposed, and the silicon base is easily oxidized by hydrogen peroxide. The oxidation strength of hydrogen peroxide at room temperature is lower than the oxidation capacity of hydrogen peroxide after heating. Therefore, room temperature chemical nickel removal can effectively reduce the degree of oxidation of the silicon layer of the cell by the nickel removal agent, so that the secondary nickel plating has good contact with the silicon base of the cell, reduce the series resistance, and improve the photoelectric conversion efficiency. At the same time, if the sulfuric acid / hydrogen peroxide is heated, the decomposition of hydrogen peroxide will be accelerated, and the cost consumed for a long time is relatively large. The use of room temperature chemical nickel removal can effectively reduce the cost of consumables.

[0018] Preferably, the nickel ion concentration in the nickel removal agent to which nickel ions are added is 5-10 g / L;

[0019] The nickel ions include one of nickel sulfate, nickel sulfamate, and nickel metal.

[0020] In the present invention, it can be seen from the process of nickel removal by sulfuric acid / hydrogen peroxide that the nickel coating is first oxidized by hydrogen peroxide to NiO, and then reacts with sulfuric acid to generate nickel sulfate, thereby achieving the effect of nickel removal. When the nickel removal agent contains nickel ions, the reaction of sulfuric acid with nickel ions takes precedence over that of sulfuric acid with nickel oxide, thereby achieving the effect of protecting the substrate. Adding nickel ions plays a buffering role, slowing down the speed of nickel removal, so as to achieve the effect of protecting the substrate.

[0021] In a second aspect, the present invention provides a method for preparing a TOPCon cell, comprising the following steps: coating, nickel plating, chemical nickel removal, and double-sided electroplating are sequentially performed on a substrate of a TOPCon solar cell to obtain a TOPCon solar cell;

[0022] The chemical nickel removal adopts the chemical nickel removal method of the TOPCon battery.

[0023] Preferably, the coating comprises: depositing a passivation film on the substrate surface of the TOPCon solar cell to obtain a coated sheet;

[0024] Preferably, the thickness of the TOPCon solar cell passivation film is 80-100nm, for example, it can be 80nm, 81nm, 82nm, 83nm, 84nm, 85nm, 86nm, 87nm, 88nm, 89nm, 90nm, 91nm, 92nm, 93nm, 94nm, 95nm, 96nm, 97nm, 98nm, 99nm, 100nm, etc.

[0025] Preferably, the coating further comprises: grooving the coating sheet and forming a grid line pattern on the surface of the coating sheet;

[0026] Preferably, the width of the groove is 10-15um, for example, it can be 10um, 11um, 12um, 13um, 14um, 15um, etc.;

[0027] Preferably, the depth of the groove is 80-100nm, for example, it can be 80nm, 81nm, 82nm, 83nm, 84nm, 85nm, 86nm, 87nm, 88nm, 89nm, 90nm, 91nm, 92nm, 93nm, 94nm, 95nm, 96nm, 97nm, 98nm, 99nm, 100nm, etc.

[0028] In the present invention, in order to expose the silicon on the substrate of the solar cell, the groove depth needs to be the same as the thickness of the passivation film. For example, if the thickness of the passivation film is 80nm, the groove depth is 80nm; if the thickness of the passivation film is 100nm, the groove depth is 100nm.

[0029] Preferably, the nickel plating comprises: electroplating nickel on the slotted battery cell and performing annealing treatment;

[0030] Preferably, the number of times of electroplating and depositing nickel is at least once;

[0031] Preferably, the thickness of each nickel plating is 1-3um, for example, 1um, 2um, 3um, etc.;

[0032] Preferably, the annealing temperature is 300-350°C, for example, it may be 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, etc.

[0033] Preferably, the specific steps of the double-sided electroplating are: performing double-sided electroplating on the nickel-removed cell to obtain a double-sided electroplated TOPCon solar cell;

[0034] Preferably, nickel, copper and tin are electroplated on the front and back sides of the TOPCon solar cell to obtain a double-sided TOPCon-plated solar cell.

[0035] The present invention adopts a preparation process of nickel plating-nickel removal-nickel copper tin plating, which can effectively improve the bonding force of the battery cell electrode grid line.

[0036] As a preferred technical solution of the present invention, the preparation method of the TOPCon battery comprises the following steps:

[0037] Coating: depositing a passivation film on the substrate surface of the TOPCon solar cell to obtain a coated sheet; making grooves on the coated sheet and forming a grid line pattern on the surface of the coated sheet, wherein the depth of the groove is the same as the thickness of the passivation film;

[0038] Nickel plating: The slotted cells are electroplated with nickel and then annealed;

[0039] Chemical nickel removal: The annealed battery cells are subjected to chemical nickel removal. Specifically, the annealed battery cells are inserted into a flower basket and immersed in a bubbling nickel removal agent tank. After being placed for a period of time, they are taken out for washing and drying. The nickel removal agent contains nickel ions.

[0040] Double-sided electroplating: The nickel-removed battery cell is subjected to double-sided electroplating to obtain a double-sided electroplated TOPCon battery.

[0041] In a third aspect, the present invention provides a TOPCon battery, wherein the TOPCon battery is prepared according to the preparation method described in the second aspect.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] In the preparation method of the TOPCon battery provided by the present invention, the substrate of the TOPCon solar cell is subjected to film coating, nickel plating, chemical nickel removal, and double-sided electroplating in sequence to obtain the TOPCon solar cell, and nickel ions are added to the nickel removal agent used in the chemical nickel removal to slow down the nickel removal rate and reduce the oxidation of the substrate by the nickel removal agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 This is a schematic diagram of the TOPCon solar cell prepared in Example 6 under a microscope;

[0046] Figure 2 This is a schematic diagram of the TOPCon solar cell prepared in Comparative Example 1 under a microscope;

[0047] Figure 3 This is a schematic diagram of the TOPCon solar cell prepared in Comparative Example 2 under a microscope. DETAILED DESCRIPTION

[0048] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear, however, in the case of any potential ambiguity, the definitions provided herein take precedence over any dictionary or external definitions. In this application, unless otherwise stated, the use of "or" means "and / or". In addition, the use of the term "including" and other forms is non-limiting.

[0049] Generally, the nomenclature and its technology used in conjunction with cell and tissue culture, molecular biology, immunology, microbiology, genetics, and protein and nucleic acid chemistry and hybridization described herein are those well-known and commonly used in the art. Unless otherwise indicated, the methods and techniques of the present invention are generally carried out according to conventional methods as well-known in the art, and as described in various general and more specific references, which are cited and discussed throughout this specification. Enzymatic reactions and purification techniques are carried out according to the manufacturer's specifications, as generally achieved in the art, or as described herein. The nomenclature and its laboratory procedures and technology used in conjunction with analytical chemistry, synthetic organic chemistry, and medical and pharmaceutical chemistry described herein are those well-known and commonly used in the art.

[0050] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or directly purchased from the market.

[0052] Example 1

[0053] This embodiment provides a method for preparing a TOPCon battery, and the preparation method comprises the following steps:

[0054] Coating: Using the PECVD process, a silicon nitride passivation film with a thickness of 80-100nm is deposited on the front and back of the TOPCon solar cell to obtain a coated sheet; then a laser is used to make grooves on the front and back of the cell to form a grid line pattern on the surface of the coated sheet; the width of the laser groove is 10-15um and the depth is 80-100nm. The depth of the groove is the same as the thickness of the passivation film;

[0055] Nickel plating: Electroplating the slotted cells with nickel, the number of times of nickel plating is at least once, the thickness of each nickel plating is 1-3um, and then annealing is performed;

[0056] The nickel plating is carried out by electroplating, the material used for the nickel plating is one of nickel sulfamate, nickel sulfate and nickel bromide, the temperature is 50°C, and the time is 50s;

[0057] Wherein, the annealing temperature is 300-350°C.

[0058] Chemical nickel removal: insert the annealed battery cell into a basket and immerse it in a bubbling nickel removal tank. During the nickel removal process, keep the temperature at 20°C. After leaving it for 5 minutes, take it out for washing and drying.

[0059] Wherein, the nickel removal agent is sulfuric acid / hydrogen peroxide, and the ratio of sulfuric acid / hydrogen peroxide is 100-150ml / L / 100-200ml / L;

[0060] Nickel sulfate is added to the nickel remover, and the nickel ion concentration in the nickel remover with nickel sulfate added is 5g / L. Double-sided electroplating: nickel, copper and tin are electroplated on the front and back of the TOPCon solar cell to obtain a double-sided TOPCon cell;

[0061] Among them, nickel plating adopts electroplating method, the material used is one of nickel sulfamate, nickel sulfate, and nickel bromide, the temperature is 50°C, and the time is 50s; copper plating adopts electroplating method, the material used is copper sulfate, and the time is 3min; tin plating adopts electroplating method, the material used is tin methylsulfonate, the temperature is 18°C, and the time is 90s.

[0062] Example 2

[0063] This embodiment provides a method for preparing a TOPCon battery, which is different from Embodiment 1 only in that nickel sulfate is added to the nickel removal agent, and the nickel ion concentration in the nickel removal agent with nickel sulfate added is 8 g / L. The other steps are completely consistent with Embodiment 1.

[0064] Example 3

[0065] This embodiment provides a method for preparing a TOPCon battery, which is different from Embodiment 2 only in that the nickel removal time is 7 minutes, and the other steps are completely consistent with Embodiment 2.

[0066] Example 4

[0067] This embodiment provides a method for preparing a TOPCon battery, which is different from Embodiment 2 only in that the nickel removal time is 10 minutes, and the other steps are completely consistent with Embodiment 2.

[0068] Example 5

[0069] This embodiment provides a method for preparing a TOPCon battery, which is different from Embodiment 1 only in that nickel sulfate is added to the nickel removal agent, and the nickel ion concentration in the nickel removal agent with nickel sulfate added is 10 g / L. The other steps are completely consistent with Embodiment 1.

[0070] Example 6

[0071] This embodiment provides a method for preparing a TOPCon battery, which is different from Embodiment 2 only in that, in the chemical nickel removal step, the temperature is maintained at 25° C., and the other steps are completely consistent with Embodiment 2.

[0072] Example 7

[0073] This embodiment provides a method for preparing a TOPCon battery, which is different from Embodiment 6 only in that, in the chemical nickel removal step, nickel sulfamate is added to the nickel removal agent, and the nickel ion concentration in the nickel removal agent with added nickel sulfamate is 8 g / L. The other steps are exactly the same as Embodiment 6.

[0074] Example 8

[0075] This embodiment provides a method for preparing a TOPCon battery, which is different from Embodiment 6 only in that, in the chemical nickel removal step, metallic nickel is added to the nickel removal agent, and the nickel ion concentration in the nickel removal agent with added metallic nickel is 8 g / L. The other steps are exactly the same as Embodiment 6.

[0076] Example 9

[0077] This embodiment provides a method for preparing a TOPCon battery, which is different from Embodiment 6 only in that, in the chemical nickel removal step, the nickel removal agent is sulfuric acid with a concentration of 40%, and the other steps are completely consistent with Embodiment 6.

[0078] Example 10

[0079] This embodiment provides a method for preparing a TOPCon battery, which is different from Embodiment 6 only in that, in the chemical nickel removal step, the nickel removal agent is nitric acid with a concentration of 60%, and the other steps are completely consistent with Embodiment 6.

[0080] Embodiment 11

[0081] This embodiment provides a method for preparing a TOPCon battery, which is different from Embodiment 6 only in that, in the chemical nickel removal step, the temperature is maintained at 35° C., and the other steps are completely consistent with Embodiment 6.

[0082] Example 12

[0083] This embodiment provides a method for preparing a TOPCon battery, which is different from Embodiment 6 only in that, in the chemical nickel removal step, the temperature is maintained at 45° C., and the other steps are completely consistent with Embodiment 6.

[0084] Embodiment 13

[0085] This embodiment provides a method for preparing a TOPCon battery, which is different from Embodiment 6 only in that, in the chemical nickel removal step, nickel sulfate is added to the nickel removal agent at a concentration of 2 g / L, and the nickel ion concentration of the nickel removal agent to which nickel sulfate is added is 2 g / L. The other steps are exactly the same as those in Embodiment 6.

[0086] Embodiment 14

[0087] This embodiment provides a method for preparing a TOPCon battery, which is different from Embodiment 6 only in that, in the chemical nickel removal step, nickel sulfate is added to the nickel removal agent, and the nickel ion concentration in the nickel removal agent with added nickel sulfate is 15 g / L. The other steps are exactly the same as Embodiment 6.

[0088] Comparative Example 1

[0089] The comparative example provides a method for preparing a TOPCon battery, which is different from Example 6 only in that, in the chemical nickel removal step of Comparative Example 1, nickel ions are not added to the nickel removal agent, and the other steps are completely consistent with Example 6.

[0090] Comparative Example 2

[0091] The comparative example provides a method for preparing a TOPCon battery, which differs from Example 6 only in that, in the chemical nickel removal step of Comparative Example 2, the temperature is maintained at 45°C, and no nickel ions are added to the nickel removal agent. The other steps are completely consistent with Example 6.

[0092] Test Example 1

[0093] Welding tensile test

[0094] Test samples: TOPCon solar cells prepared in Examples 1-14 and TOPCon solar cells prepared in Comparative Example 1;

[0095] Test method: Weld the welding rod to 12 pad points of the battery cell and use a dynamometer to measure the welding tension;

[0096] The specific test results are shown in Table 1:

[0097] Table 1

[0098]

[0099] It can be seen from the test data in Table 1 that the TOPCon solar cell prepared by the preparation method of the present invention is subjected to a welding tensile test, and the welding tensile forces on the front and back of the cell are both above 2N, indicating that the entire coating obtained by the preparation method of the present invention has good bonding strength with the silicon substrate, the bonding strength of the metal grid electrode is good, and the welding tensile force also meets the requirements.

[0100] Test Example 2

[0101] Electrical performance test

[0102] Test samples: TOPCon solar cells prepared in Examples 1-14 and TOPCon solar cells prepared in Comparative Examples 1-2;

[0103] Test method: Measure the photoelectric conversion efficiency of the complete cell on an efficiency tester.

[0104] The specific test results are shown in Table 2:

[0105] Table 2

[0106]

[0107] It can be seen from the test data in Table 2 that the preparation method of the present invention adopts room temperature chemical nickel removal and adds nickel ions to the nickel removal base, which can effectively reduce the degree of oxidation of the silicon layer of the battery cell by the nickel removal agent, so that the secondary nickel plating has good contact with the silicon base of the battery cell, reduce the series resistance, and improve the photoelectric conversion efficiency.

[0108] Test Example 3

[0109] Nickel removal effect

[0110] Test samples: TOPCon solar cells prepared in Example 6, and TOPCon solar cells prepared in Comparative Examples 1 and 2.

[0111] Test method: Observe the nickel removal effect of battery cells using different methods through a microscope.

[0112] Specific test results are as follows Figure 1 , Figure 2 and Figure 3 As shown, Figure 1-3 In the figure, the white fish-scale area (including the horizontal and vertical bars in the figure, both of which are the grid lines of the battery) is the area where nickel is plated after grooving and then removed, and the blue area is the passivation film area without grooving.

[0113] Figure 1 This is the nickel removal effect diagram of chemical nickel removal at room temperature of 25°C and adding nickel ions. It can be seen that after nickel removal, a large area of ​​battery silicon wafers are exposed in the gate line area, and the color is basically white, which reduces the oxidation of the silicon wafer substrate by the nickel removal agent and has an excellent nickel removal effect.

[0114] Figure 2 The nickel removal effect diagram of chemical nickel removal at room temperature 25℃ without adding nickel ions. It can be seen that after nickel removal, compared with Figure 1 , the gate line area, the exposed area of ​​the battery silicon wafer is reduced, and from Figure 2 It can be seen that there is a black part in the silicon layer of the battery, which means that oxidation has occurred, and the nickel removal effect is obviously not as good as Figure 1 .

[0115] Figure 3 This is the effect diagram of chemical nickel removal at a temperature of 45°C. It can be seen that after nickel removal, the degree of oxidation of the battery silicon layer is aggravated. Figure 3 The nickel removal effect is obviously not as good as Figure 2 .

[0116] In summary, the TOPCon solar cell prepared by the preparation method of the present invention has a better nickel removal effect.

[0117] The preparation method of the TOPCon battery provided in this embodiment adopts a method of room temperature chemical nickel removal and nickel ion addition, which reduces losses while achieving excellent nickel removal effects, thereby improving the photoelectric conversion efficiency and bonding strength of the battery cell.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A chemical nickel removal method for TOPCon batteries, characterized in that: The following steps are involved: A TOPCon solar cell is subjected to chemical nickel removal using a nickel removal agent; nickel ions are added to the nickel removal agent; the chemical nickel removal temperature is 20-25° C., the nickel removal agent is a mixture of sulfuric acid and hydrogen peroxide; the nickel ion concentration in the nickel removal agent added with nickel ions is 5-10 g / L; Before the chemical nickel removal, the silicon substrate is subjected to sequential deposition of a passivation film, grooving and nickel plating.

2. The method for chemical nickel removal of TOPCon battery according to claim 1, characterized in that: The chemical nickel removal comprises: inserting the annealed battery sheet into a flower basket, immersing the battery sheet in a bubbling nickel removal agent tank, and then washing and drying the battery sheet in sequence.

3. The chemical nickel removal method of TOPCon battery according to claim 1, characterized in that: The nickel removal agent includes at least one of a mixture of sulfuric acid and hydrogen peroxide, sulfuric acid and nitric acid.

4. The method for chemical nickel removal of TOPCon battery according to claim 1, characterized in that: The time for chemical nickel removal is 5-10 min.

5. The method for chemical nickel removal of TOPCon battery according to claim 1, characterized in that: The ratio of the sulfuric acid to the hydrogen peroxide is 100-150 ml / L / 100-200 ml / L.

6. The chemical nickel removal method of TOPCon battery according to claim 1, characterized in that the nickel ions include at least one of nickel sulfate, nickel sulfamate, and nickel metal.

7. A method for preparing a TOPCon battery, characterized in that: The following steps are involved: The substrate of the TOPCon solar cell is subjected to film coating, nickel plating, chemical nickel removal, and double-sided electroplating in sequence to obtain a TOPCon solar cell; The chemical nickel removal adopts the chemical nickel removal method of the TOPCon battery as described in any one of claims 1 to 6.

8. The method for preparing a TOPCon battery according to claim 7, characterized in that: The coating comprises: depositing a passivation film on the substrate surface of the TOPCon solar cell to obtain a coating sheet.

9. The method for preparing a TOPCon battery according to claim 8, characterized in that: The thickness of the passivation film is 80-100 nm.

10. The method for preparing a TOPCon battery according to claim 8, characterized in that: The coating process also includes: grooving the coating sheet and forming a grid line pattern on the surface of the coating sheet.

11. The method for preparing a TOPCon battery according to claim 10, characterized in that: The width of the groove is 10-15 um.

12. The method for preparing a TOPCon battery according to claim 10, characterized in that: The depth of the groove is 80-100 nm, and the depth of the groove is the same as the thickness of the passivation film.

13. The method for preparing a TOPCon battery according to claim 7, characterized in that: The nickel plating comprises: electroplating nickel on the slotted battery cell, and then performing annealing treatment.

14. The method for preparing a TOPCon battery according to claim 13, characterized in that: The number of times of electroplating nickel deposition is at least one, and the thickness of each nickel plating is 1-3 um.

15. The method for preparing a TOPCon battery according to claim 13, characterized in that: The annealing temperature is 300-350°C.

16. The method for preparing a TOPCon battery according to claim 7, characterized in that: The double-sided electroplating comprises: electroplating nickel, copper and tin on the front and back sides of the TOPCon cell to obtain a double-sided TOPCon plated solar cell.

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