Grid line preparation method of perovskite laminated cell, cell and preparation method thereof

Abstract

The invention provides a preparation method of a grid line of a perovskite laminated cell, the cell and a preparation method of the cell, and relates to the technical field of solar cells. The preparation method of the grid line of the perovskite laminated cell comprises the following steps: S1, respectively forming electroplating electrode holes in the front surface and the back surface of the perovskite laminated cell to be manufactured by the grid line; s2, double-sided copper electroplating is adopted, a grid line is prepared at an electroplating electrode opening through an oxidation-reduction reaction, and preparation of copper electrodes on the front surface and the back surface of the cell is achieved; wherein an AlOx protection layer is prepared on the front surface of the perovskite laminated cell to be manufactured by the grid line; the electroplating temperature of the double-sided copper electroplating is 20-60 DEG C. According to the invention, the grid line is prepared by combining the AlOx protection layer with the low-temperature electroplating process, so that the cost is reduced, the cell performance is improved, the consumption of silver paste is reduced, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to a method for fabricating grid lines, a cell, and a method for fabricating perovskite tandem solar cells. Background Technology

[0002] Against the backdrop of a global push for energy transition and vigorous development of renewable energy, photovoltaic (PV) power generation, as a highly promising method for acquiring clean energy, has attracted widespread attention. Tandem solar cells, especially TOPCon / perovskite tandem solar cells, have become a research focus and development direction in the photovoltaic field due to their theoretically much higher photoelectric conversion efficiency than single-junction cells. By stacking materials with different bandgap widths, they broaden the absorption range of the solar spectrum, with theoretical efficiencies expected to exceed 40%, providing a new pathway for the efficient utilization of solar energy. However, the large-scale commercial application of tandem solar cells currently faces numerous challenges, with cost being a particularly prominent issue. Taking the electrode component as an example, it accounts for a significant proportion of the cost of tandem solar cells. On the one hand, traditional tandem solar cells often use precious metals such as silver as electrode materials, and the high price of silver keeps raw material costs high. On the other hand, the electrode fabrication process is complex. Whether it's the requirement for high-resolution patterning in the printing process or ensuring a balance between electrode conductivity and light transmittance, many technical challenges exist, further increasing electrode fabrication costs and the overall cost of the battery. Therefore, developing new electrode materials and fabrication processes to reduce the cost of the electrode component in tandem solar cells is crucial for promoting the large-scale application of tandem solar cells.

[0003] CN119133311A discloses a method and apparatus for preparing photovoltaic cell grid lines, comprising: obtaining a grid line preparation piece, which is a photovoltaic cell semi-finished product containing a dielectric layer before electroplating the grid lines; opening a film on the grid line preparation piece to form a strip-shaped conductive area from one side of the grid line preparation piece to the other side, the conductive area being used to connect to an external electrode; patterning the grid line preparation piece after opening the film, removing the dielectric layer of the grid line preparation piece to form a contact area for the grid lines; preparing the grid lines in the contact area by an electroplating process, wherein during the electroplating of the grid lines, the conductive area on the grid line preparation piece is connected to the external electrode, and the grid line preparation piece is placed horizontally and in contact with the electroplating solution. The prior art discloses a method for preparing grid lines by electroplating. However, this method is mainly applicable to silicon-based cells. For perovskite cells or perovskite tandem cells, there are still a series of problems with preparing grid lines by electroplating copper. For example, the instability of perovskite, the need for aqueous solutions or polar electrolytes for electroplating, the easy hydrolysis and decomposition of perovskite when exposed to water, which leads to the destruction of crystal structure and a sharp drop in photoelectric performance, and the process conditions of electroplating also affect the stability of the perovskite layer.

[0004] Therefore, there is an urgent need to provide a method for fabricating grid lines in perovskite tandem solar cells to solve the aforementioned problems. Summary of the Invention

[0005] This invention addresses the shortcomings of current methods for fabricating grid lines in perovskite tandem solar cells. These methods require expensive low-temperature silver paste for the top cell portion, increasing costs. Furthermore, they necessitate two-step screen printing with varying parameter requirements, increasing production difficulty. Additionally, the stability of the perovskite layer is not suitable for electroplating methods used in grid line fabrication. This invention provides a method for fabricating grid lines in perovskite tandem solar cells. By combining a specific perovskite structure with a low-temperature copper electroplating process, the grid lines of the perovskite tandem solar cells are fabricated, reducing production costs while ensuring relevant cell performance.

[0006] Another object of the present invention is to provide a method for preparing perovskite tandem solar cells.

[0007] In a first aspect, the present invention protects a method for fabricating grid lines in a perovskite tandem solar cell, comprising the following steps: S1. Electroplated electrode openings are formed on the front and back surfaces of the perovskite tandem solar cell to be fabricated. S2. Double-sided copper electroplating is used to prepare grid lines at the openings of the electroplated electrodes by utilizing redox reactions, thereby realizing the preparation of copper electrodes on the front and back surfaces of the battery; The positive surface of the perovskite tandem solar cell to be fabricated with the gate line is prepared with AlO. x Protective layer; The electroplating temperature for the double-sided copper plating is 20~60℃.

[0008] According to the grid line fabrication method of the perovskite tandem solar cell protected by the present invention, preferably, the AlO₂ on the front surface of the perovskite tandem solar cell... x The thickness of the protective layer is 4~15nm.

[0009] According to the method for fabricating grid lines of a perovskite tandem solar cell protected by the present invention, preferably, the grid lines have a linewidth of 5-15 μm and a resistivity of 1.3-2.0 × 10⁻⁶. -8 Ω·m, and the thickness of the gate line is 6.5~19.5μm.

[0010] According to the grid line fabrication method of the perovskite tandem solar cell protected by the present invention, preferably, in S1, NaOH is inkjet printed on the front surface of the perovskite tandem solar cell to remove part of AlO on the front surface. x A protective layer is formed to create openings in the electroplated electrode.

[0011] According to the grid line fabrication method of the perovskite tandem solar cell protected by the present invention, preferably, in S1, laser grooving is performed on the back surface of the perovskite tandem solar cell to remove the back surface portion and form an electroplated electrode opening.

[0012] Secondly, the present invention also specifically protects a method for preparing a perovskite / TOPCon tandem solar cell, wherein the grid lines are prepared using the grid line preparation method of the perovskite tandem solar cell.

[0013] The method for preparing the perovskite / TOPCon tandem solar cell protected by the present invention preferably includes the following steps: S1: Texturing the silicon substrate and back-side diffusion to prepare the P+ emitter; S2: A tunneling oxide layer and a doped polysilicon layer are sequentially prepared on the front side of the silicon substrate. The front PSG is removed, and the back BSG is retained. S3: An interface interconnect layer is prepared on the front side. A hole transport layer, a perovskite layer, an electron transport layer, a passivation layer, and a transparent conductive film are prepared sequentially on top of the front interconnect layer. The BSG on the back side is removed by acid washing. S4: Simultaneously prepare AlOx layers on the front and back sides, and continue to prepare an antireflection layer on the back side; S5: The grid lines are fabricated using the grid line fabrication method of the perovskite tandem solar cell.

[0014] According to the fabrication method of the perovskite / TOPCon tandem solar cell protected by the present invention, preferably, the thickness of the hole transport layer in S3 is 2~30nm, more preferably 10~15nm; And / or, the thickness of the perovskite layer is 400~700nm, preferably 450~500nm; And / or, the thickness of the electron transport layer is 15~30nm, preferably 18~22nm; And / or, the thickness of the passivation layer is 2~20nm, preferably 10~15nm; And / or, the thickness of the transparent conductive film is 60~140nm, preferably 70~85nm.

[0015] According to the method for preparing the perovskite / TOPCon tandem solar cell protected by the present invention, preferably, the silicon substrate in S1 is an N-type silicon wafer with a thickness of 120~220μm; The thickness of the tunneling oxide layer described in S2 is 0.5~2nm, and the thickness of the doped polycrystalline silicon is 30~200nm.

[0016] Thirdly, the present invention also specifically protects a method for preparing a perovskite / TOPCon tandem solar cell, which comprises, from bottom to top, an antireflection layer, a passivation layer, a p+ emitter, a silicon substrate, a tunneling oxide layer, a doped polycrystalline silicon layer, an interface interconnect layer, a hole transport layer, a perovskite layer, an electron transport layer, a transparent conductive layer, a protective layer, and a metal electrode.

[0017] Beneficial effects: This invention provides a method for fabricating grid lines in a perovskite tandem solar cell, by preparing AlO2 on the positive surface of the perovskite tandem solar cell. x A protective layer is used to prevent corrosion during the electroplating process. Combined with a low-temperature electroplating process, the grid lines are prepared, thereby reducing costs and improving battery performance.

[0018] The present invention also provides a method for preparing a perovskite / TOPCon tandem solar cell. The grid line preparation method adopted in the present invention uses copper electroplating technology to prepare the grid line electrodes of the tandem solar cell, which reduces the consumption of silver paste and can use a double-sided electroplating process, further simplifying the process flow, reducing production costs, and improving electrical performance. Attached Figure Description

[0019] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the perovskite / TOPCon tandem solar cell of the present invention, wherein 1 is an antireflection layer; 2 is a passivation layer (protective layer); 3 is a p+ emitter; 4 is an n-Si layer; 5 is a tunneling layer; 6 is an n+ poly layer; 7 is an interface interconnect layer; 8 is a hole transport layer; 9 is a perovskite layer; 10 is an electron transport layer; 11 is a transparent conductive layer; and 12 is a metal electrode. Detailed Implementation

[0021] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention. Where specific techniques or conditions are not specified in the examples, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased from legitimate channels.

[0022] Terminology Explanation: BSG: Glass doped with boron (B), usually produced after boron doping.

[0023] PSG: P-doped glass, usually produced after P doping.

[0024] In a specific embodiment, the present invention provides a method for fabricating grid lines in a perovskite tandem solar cell, comprising the following steps: S1. Electroplated electrode openings are formed on the front and back surfaces of the perovskite tandem solar cell to be fabricated. S2. Double-sided copper electroplating is used to prepare grid lines at the openings of the electroplated electrodes by utilizing redox reactions, thereby realizing the preparation of copper electrodes on the front and back surfaces of the battery; The positive surface of the perovskite tandem solar cell to be fabricated with the gate line is prepared with AlO. x Protective layer; The electroplating temperature for the double-sided copper plating is 20~60℃.

[0025] It should be noted that: In the perovskite tandem solar cell grid line fabrication method provided by this invention, a special structural improvement is made for perovskite tandem solar cells that are not suitable for copper plating to fabricate grid lines. AlO is prepared on the front surface of the perovskite tandem solar cell, i.e., the surface of the perovskite top cell. x Protective layer, front AlO x Acting as a protective layer for perovskite, it prevents the electroplating solution from eroding the perovskite material. Furthermore, combined with the low-temperature copper electroplating process of 30-60°C of this invention, damage to the perovskite film can be further reduced. The high-temperature sintering process of screen printing can "burn through" the passivation layer (such as SiN) on the battery surface. x / AlO x This leads to increased recombination in the metal-silicon contact area, reducing the open-circuit voltage (Voc).

[0026] The low-temperature copper electroplating process of this invention is a low-temperature process (20~60℃), which completely avoids the damage to the silicon wafer and passivation layer caused by high temperature, and can better maintain the original high Voc of the battery.

[0027] Using copper electroplating to fabricate metal grid lines reduces the consumption of silver paste and allows for double-sided electroplating, further streamlining the process and lowering production costs. Electroplating copper significantly improves photoelectric conversion efficiency, results in lower electrode resistance, and allows for simultaneous plating of both sides, leading to even higher efficiency.

[0028] In some specific embodiments, the AlO₂ on the positive surface of the perovskite tandem solar cell mentioned in this invention x The thickness of the protective layer is 4~15nm, for example, it can be a point value of 4nm, 6nm, 8nm, 10nm, 12nm, 15nm, or any range of values.

[0029] AlO x If the film layer is too thin, discontinuities may occur during deposition, forming pinholes at certain locations. This fails to effectively block the plating solution and reduces the passivation effect on the battery surface. Furthermore, in the specific fabrication process using AlOx double-sided deposition, an excessively thin silicon surface on the other side can cause charge carriers to recombine with the silicon surface through pinholes, reducing open-circuit voltage and short-circuit current. Conversely, an excessively thick film can obstruct carrier transport, increase series resistance, and accumulate significant internal stress, leading to poor adhesion to the substrate and reduced passivation. Therefore, it is crucial to optimize the film thickness within the range of 4–15 nm.

[0030] In some specific exemplary embodiments, the present invention further preferably controls the linewidth of the gate lines prepared in step S2 to be 5-15 μm and the resistivity to be 1.3-2.0 × 10⁻⁶. -8 The resistance is Ω·m, and the gate line thickness is 6.5~19.5μm. For example, the specific gate line width can be 5μm, 8μm, 10μm, 12μm, 15μm, etc., or any range of values. The resistivity can be 1.3×10⁻⁶. -8 Ω·m, 1.5×10 -8 Ω·m, 1.8×10 -8 Ω·m, 2.0×10 -8 The grid line thickness can be a point value such as Ω·m or any range of arbitrary configurations, for example, a point value such as 6.5μm, 10.4μm, 11.3μm, 15.6μm, 19.5μm or any range of arbitrary configurations.

[0031] The resistivity of the gate wires prepared by electroplated copper, preferably provided by this invention, is 1.3-2.0 × 10⁻⁶. -8 Ω·m, resistivity of copper (~1.7×10⁻⁶) -8 The Ω·m value is much higher than that of low-temperature silver paste (~3×10). -8 The Ω·m value significantly reduces the series resistance (Rs) of the electroplated gate lines and greatly improves the fill factor (FF), typically increasing the absolute efficiency by 0.3%-0.5%.

[0032] Due to the limitations of the paste rheological properties, the aspect ratio (height / width) of the grid lines in screen printing is typically less than 0.5. In order to maintain conductivity, the grid lines must be made relatively wide (>30μm), which blocks more light and leads to the loss of short-circuit current (Isc).

[0033] The electroplated copper used in this invention can produce "tall and narrow" grid lines with an aspect ratio easily exceeding 1.0. It can achieve greater height with a width of only 5-15 μm, thus ensuring low resistance and high current transmission capability while making the grid lines thinner. This significantly reduces the light-blocking area on the back, allowing more light to enter the battery from the back, greatly reducing the grid lines' obstruction of incident light and improving Isc (Input / Output Score).

[0034] In some specific embodiments, the forming of electroplated electrode openings on the front and back surfaces of the perovskite tandem solar cell to be fabricated, as mentioned in S1 of the present invention, can be achieved in the following ways: In S1, NaOH is inkjet-printed onto the front surface of the perovskite tandem solar cell to remove part of the AlO2 on the front surface. x A protective layer is formed to create openings for the electroplated electrodes; In S1, laser grooving is used to remove part of the back surface of the perovskite tandem solar cell to form an electroplated electrode opening.

[0035] Among these methods, inkjet printing NaOH onto the front surface of a perovskite tandem solar cell can precisely remove AlO2 from the front portion. x A protective layer is used to create openings for subsequent electrode plating. Laser grooving on the back surface of the perovskite tandem solar cell allows for precise removal of AlO₂ from the back side. x passivation layer and SiN x The anti-reflective layer is used to create openings for subsequent electroplating of electrodes.

[0036] For the perovskite film on the front side, excessively high laser energy can damage the perovskite, so a gentler chemical method is used. Crystalline silicon, on the other hand, is more stable, and laser technology is more mature for it.

[0037] In a specific embodiment, the present invention also provides a method for fabricating a perovskite / TOPCon tandem solar cell, wherein the grid lines are fabricated using the grid line fabrication method for perovskite tandem solar cells provided by the present invention.

[0038] In some specific embodiments, the method for fabricating a perovskite / TOPCon tandem solar cell mentioned in this invention may specifically include the following steps: S1: Texturing the silicon substrate and back-side diffusion to prepare the P+ emitter; S2: A tunneling oxide layer and a doped polysilicon layer are sequentially prepared on the front side of the silicon substrate. The front PSG is removed, and the back BSG is retained. S3: An interface interconnect layer is prepared on the front side. A hole transport layer, a perovskite layer, an electron transport layer, a passivation layer, and a transparent conductive film are prepared sequentially on top of the front interconnect layer. The BSG on the back side is removed by acid washing. S4: Simultaneously prepare AlOx layers on the front and back sides, and continue to prepare an antireflection layer on the back side; S5: The grid lines are prepared using the grid line preparation method for perovskite tandem solar cells provided in this invention.

[0039] In some specific embodiments, the present invention also achieves better perovskite / TOPCon tandem solar cell fabrication results by preferentially controlling the following parameters:

[0040] In some specific exemplary embodiments, the thickness of the hole transport layer in S3 is 2~30nm, for example, it can be a point value or any range of values ​​such as 2nm, 5nm, 8nm, 10nm, 12nm, 15nm, 18nm, 20nm, 22nm, 25nm, 28nm, 30nm, etc., preferably 10~15nm.

[0041] The thinner the hole transport layer, the better the light transmission. However, if it is too thin, the hole transport capability will be poor. Therefore, the preferred range is 10~15nm.

[0042] The thickness of the perovskite layer is 400~700nm, for example, it can be a point value of 400nm, 500nm, 600nm, 700nm, or any range of values, preferably 450~500nm.

[0043] The thickness of the electron transport layer is 15~30nm, for example, it can be a point value of 15nm, 18nm, 21nm, 24nm, 26nm, 30nm or any range of values, preferably 18~22nm.

[0044] The thickness of the passivation layer is 2~20nm, for example, it can be a point value of 2nm, 5nm, 10nm, 12nm, 15nm, 18nm, 20nm or any range of values, preferably 10~15nm.

[0045] The thickness of the transparent conductive film is 60~140nm, for example, it can be a point value of 60nm, 80nm, 100nm, 120nm, 140nm or any range of values, preferably 70~85nm.

[0046] In some specific embodiments, the silicon substrate mentioned in this invention is preferably an N-type silicon wafer with a thickness of 120~220μm.

[0047] In some specific embodiments, the thickness of the tunneling oxide layer mentioned in this invention is preferably 0.5~2nm, and the thickness of the doped polycrystalline silicon is 30~200nm.

[0048] In some specific embodiments, the materials of each layer of the present invention may preferably be as follows: The anti-reflection layer is: SiN x (Silicon nitride), TiO2 (titanium dioxide), SiO2 (silicon dioxide), AlO x (Alumina) or any one or two of them.

[0049] The passivation layer for crystalline silicon is: AlO x (alumina), SiN x (Silicon nitride) or any one or two of them.

[0050] P+ emitter: B-doped crystalline silicon.

[0051] The interface interconnect layer consists of: ITO nanoparticles (NPs) / PEDOT:PSS (poly(3,4-ethylenedioxythiophene:polystyrene sulfonate), ZnO / metal oxides (such as MoO) x V2O5, WO x It can be any one of SnO2 / metal oxide, TCO (transparent conductive adhesive), p+ poly layer, etc.

[0052] The hole transport layer can be selected from any one or more electron transport materials such as NiOx (nickel oxide), MoOx (molybdenum oxide), V2O5 (vanadium oxide), Cu2O (cuprous oxide), PTAA, and Spiro-OMeTAD.

[0053] The perovskite layer can contain compounds with an ABX3 structure, where A represents a cation and can be Cs. + Methylamine (CH3NH3) + ), formamidin (NH=CHNH3) + Any one or more of the following; B represents a divalent metal ion, which can be Pb. 2+ Sn 2+ Any one or more of the following; X represents a halide anion, which can be Cl... - ,Br - I - Any one or more of the following.

[0054] The electron transport layer can be selected from SnOx (tin oxide), TiOx (titanium oxide), ZnO (zinc oxide), WOx (tungsten oxide), C 60 Any one or more of hole transport materials such as fullerenes and PCBMs (fullerene derivatives).

[0055] The passivation layer can be selected from: BCP (Bath Copper), PMMA (Polymethyl Methacrylate), PY-NFAs (Polymeric Y-series Non-Fullerene Acceptors), SnO x One of the (tin oxide) compounds.

[0056] The transparent conductive layer is any one of the following transparent conductive oxides: ITO (indium tin oxide), IZO (zinc oxide doped with indium), FTO (tin oxide doped with fluorine), AZO (zinc oxide doped with aluminum), GZO (zinc oxide doped with gallium), IWO (indium oxide doped with tungsten).

[0057] In a specific embodiment, the present invention also provides a method for preparing a perovskite / TOPCon tandem solar cell, such as... Figure 1 The structure, from bottom to top, includes an antireflection layer, a passivation layer, a p+ emitter, a silicon substrate, a tunneling oxide layer, a doped polysilicon layer, an interface interconnect layer, a hole transport layer, a perovskite layer, an electron transport layer, a transparent conductive layer, a protective layer, and a metal electrode.

[0058] Example 1 A method for fabricating a perovskite / TOPCon tandem solar cell includes the following steps: S1: Texturing the silicon substrate, which is an N-type silicon wafer with a thickness of 180μm, and back-side diffusion to prepare the P+ emitter; S2: A tunneling oxide layer and a polysilicon layer are deposited sequentially on the front side. The polysilicon on the front side is doped and diffused to form an n+ polysilicon layer. The thickness of the tunneling oxide layer is 1nm and the thickness of the doped polysilicon is 100nm. The PSG on the n+ poly surface on the front side is removed by acid washing, and the BSG on the back side is retained to serve as a battery protection layer. S3: An interface interconnect layer with a thickness of 10 nm is prepared on the front side. A hole transport layer, a perovskite layer, an electron transport layer, a passivation layer, and a transparent conductive film are prepared sequentially on the front interconnect layer with thicknesses of 15 nm, 500 nm, 20 nm, 10 nm, and 80 nm, respectively. The back side BSG is removed by acid washing. S4: Preparation of AlO2 on both sides x Thin film, AlO on crystalline silicon surface x AlOx on the perovskite surface acts as a passivation layer and a protective layer, preventing corrosion of the perovskite solution during subsequent electroplating. x The film thickness is 10 nm; a SiNx antireflection layer with a thickness of 80 nm is prepared on the back side; S5: Front-side inkjet printing sprays NaOH onto the electrodes to precisely remove AlO₂ from the front side. x This is to create openings for subsequent electroplating of electrodes; Backside laser grooving creates holes at the electrodes to remove some AlO2 from the back side. x SiN x The layer provides openings for subsequent electroplating of electrodes; Double-sided copper electroplating utilizes a redox reaction to prepare the copper electrodes on the front and back sides of the battery. The copper electroplating equipment can be vertical or horizontal, with a line width of 10 μm, a thickness of 13 μm, and a resistivity of 1.5 × 10⁻⁶. -8 Ω·m, copper plating temperature controlled at 40℃.

[0059] Example 2 A method for fabricating a perovskite / TOPCon tandem solar cell is basically the same as in Example 1, except that the AlO₂ on the front and back sides of the perovskite tandem solar cell is... x The thickness of the protective layer is 4nm.

[0060] Example 2 compared to Example 1: Front protective layer AlO x Thinning the film too much can lead to uneven and non-dense film deposition, reducing its effectiveness in blocking the plating solution. This can cause the plating solution to erode the protective layer, degrading the internal perovskite film, affecting battery efficiency, and even causing battery failure. Furthermore, the passivation layer on the back side will also become thinner. Defects at pinhole locations will not effectively block charge carriers, leading to field passivation failure. Charge carriers can then recombine with the silicon surface through the pinholes, reducing open-circuit voltage and short-circuit current.

[0061] Example 3 A method for fabricating a perovskite / TOPCon tandem solar cell is basically the same as in Example 1, except that the grid line width is 15 μm, the thickness is 19.5 μm, and the resistivity is 1.5 × 10⁻⁶. -8 Ω·m.

[0062] Compared to Example 1, Example 3 shows an increase in both the linewidth W and thickness H of the grid lines. While an increased linewidth inevitably leads to greater light shading, the increased linewidth and height result in lower resistance. The cross-sectional area of ​​the grid lines is A = W × H, and the resistance is R = ρ × (L / (W × H)), where ρ is the resistivity, which is the same for the same material, and L is the length of the grid lines, which is also the same for cells of the same specifications. Therefore, with the same length and material, grid lines with greater linewidth and height have better resistance and better conductivity.

[0063] Example 3 adds optical obstruction compared to Example 1, but reduces the obstruction to carrier transport. The wider linewidth increases the adhesion of the gate lines and reduces the risk of gate detachment. The linewidth can be appropriately increased while ensuring that optical obstruction losses are reduced.

[0064] Comparative Example 1 A method for fabricating a perovskite / TOPCon tandem solar cell is disclosed. The film thickness process control is basically the same as in Example 1, except that the TOPCon cell is fabricated first, and the back electrode grid lines are prepared by screen printing silver paste. Then, the perovskite cell is deposited, and the front electrode grid lines are prepared by low-temperature silver paste. The specific process is as follows: S1: Texturing the silicon substrate, which is an N-type silicon wafer with a thickness of 180μm, and back-side diffusion to prepare the P+ emitter; S2: A tunneling oxide layer and a polysilicon layer are deposited sequentially on the front side. The polysilicon on the front side is doped and diffused to form an n+ polysilicon layer. The thickness of the tunneling oxide layer is 1nm and the thickness of the doped polysilicon is 100nm. The PSG on the front n+ poly surface and the BSG on the back side are removed by acid washing. S3: Preparation of AlO on the back side x Thin film, AlO on crystalline silicon surface x AlO acts as a passivation layer x The film thickness is 10 nm; a SiNx antireflection layer with a thickness of 80 nm is prepared on the back side; S4: Preparation of back electrode: A screen printing stencil is selected, and silver paste or silver-aluminum paste is used to print the back electrode. The grid line width is 30~40μm and the thickness is 9~15μm. Then the printed silicon wafer is placed in a high-temperature furnace (600~800℃) for sintering to make the paste and silicon wafer form good ohmic contact. S5: An interface interconnect layer with a thickness of 10 nm is fabricated on the front side. A hole transport layer, a perovskite layer, an electron transport layer, a passivation layer, and a transparent conductive film are fabricated sequentially on top of the front interconnect layer, with thicknesses of 15 nm, 500 nm, 20 nm, 10 nm, and 80 nm, respectively. S6: Preparation of the front top electrode: A screen printing stencil is selected, and a low-temperature silver paste is used to print the back electrode. The grid line width is 30~40μm and the thickness is 9~15μm. Then, the printed silicon wafer is placed in an annealing furnace at a temperature below 150℃ to cure the silver paste and form a good ohmic contact.

[0065] The resistivity of copper is ~1.7×10⁻⁶. -8 The Ω·m is much lower than that of low-temperature silver paste (~3×10). -8 The perovskite / TOPCon tandem solar cell prepared in the embodiments of the present invention has a lower electrode resistance than the perovskite / TOPCon tandem solar cell of Comparative Example 1, and the absolute efficiency of photoelectric conversion efficiency is improved by 0.3%-0.5%.

[0066] Due to the limitations of the paste rheological properties, the aspect ratio (height / width) of the grid lines in screen printing is typically less than 0.5. In order to maintain conductivity, the grid lines must be made relatively wide (>30μm), which blocks more light and leads to the loss of short-circuit current (Isc).

[0067] The copper plating method used in embodiment 1 of this invention can create "tall and narrow" gate lines with an aspect ratio of over 1.0. It achieves greater height with a width of only 5-15 μm, thereby significantly reducing the gate line's obstruction of incident light and improving Isc while maintaining low resistance and high current transmission capability.

[0068] The high-temperature sintering process of screen printing in Comparative Example 1 can "burn through" the passivation layer (such as SiNx / AlOx) on the battery surface, causing increased recombination in the metal-silicon contact area and reducing the open-circuit voltage (Voc). In contrast, the electroplating process used in this invention is a low-temperature process (40°C), which completely avoids the damage to the silicon wafer and passivation layer caused by high temperature, and can better maintain the original high Voc of the battery.

[0069] Furthermore, the use of copper instead of silver in this invention significantly reduces raw material costs.

[0070] Bifaciality: This refers to the ratio of the efficiency on the back side of the battery to the efficiency on the front side, and is a key indicator for evaluating the performance of bifacial batteries. Screen-printed bifacial batteries: To maintain bifaciality, the silver paste grid lines on the back side cannot be too dense or too wide, otherwise they will block incident light from the back side, limiting the improvement of back-side power generation capacity. However, the electroplated bifacial battery of this invention allows for finer grid lines, significantly reducing the light-blocking area on the back side, allowing more light to enter the battery from the back. The finer grid lines also mean that a better grid pattern can be designed on the back side, maximizing light absorption while ensuring conductivity, achieving a bifaciality exceeding 90%, while screen printing typically only achieves 70%-85%.

[0071] Electroplating can process both sides simultaneously, making it more efficient. In contrast, screen printing requires two separate processes, and the alignment process is more time-consuming.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of manufacturing a grid line of a perovskite tandem cell, characterized by, It comprises the following steps: S1. Forming plating electrode openings on the front and back surfaces of the perovskite stacked cell to be made into grid lines; S2. Preparing grid lines by using a double-sided copper plating to prepare grid lines at the plating electrode openings through an oxidation-reduction reaction, and realizing the preparation of copper electrodes on the front and back surfaces of the cell; The positive surface of the perovskite stacked battery to be made into a gate line is prepared with AlO x protective layer The plating temperature of the double-sided copper plating is 20-60℃.

2. The method of claim 1, wherein the method further comprises: depositing a first layer of a first perovskite material on the substrate; depositing a second layer of a second perovskite material on the first layer; and depositing a third layer of a third perovskite material on the second layer. AlO of the positive surface of the perovskite tandem cell x The thickness of the protective layer is 4-15 nm.

3. The method of claim 1 or 2, wherein the method further comprises: The line width of the gate line is 5-15 μm, the resistivity is 1.3-2.0 x 10 -8 Ω·m, and the thickness of the gate line is 6.5-19.5 μm.

4. The method of claim 1 to 3, wherein the method is characterized by: In S1, NaOH is inkjet printed on the front surface of the perovskite tandem cell, removing part of the AlO on the front surface x A protective layer is formed to open the plating electrode holes.

5. The method of claim 1 to 4, wherein the method is characterized by: In S1, the back surface of the perovskite stacked cell is laser grooved to remove part of the back surface to form plating electrode openings.

6. A method for preparing a perovskite / TOPCon tandem cell, characterized in that, The grid lines are prepared by using the grid line preparation method of the perovskite stacked cell according to any one of claims 1-5.

7. The method for preparing the perovskite / TOPCon tandem solar cell according to claim 6, characterized in that, It comprises the following steps: S1: Texturing the silicon substrate, and preparing a P+ emitter by back surface diffusion; S2: Preparing a tunneling oxide layer and a doped polysilicon layer on the front surface of the silicon substrate in sequence, removing the front surface PSG, and retaining the back surface BSG; S3: Preparing an interface interconnection layer on the front surface, and preparing a hole transport layer, a perovskite layer, an electron transport layer, a passivation layer, and a transparent conductive film on the interface interconnection layer in sequence, and removing the back surface BSG by acid washing; S4: Preparing an AlOx layer on the front and back surfaces at the same time, and continuously preparing an anti-reflection layer on the back surface; S5: Preparing grid lines by using the grid line preparation method of the perovskite stacked cell according to any one of claims 1-5.

8. The method for preparing the perovskite / TOPCon tandem solar cell according to claim 7, characterized in that, The thickness of the hole transport layer in S3 is 2-30nm, preferably 10-15nm; And / or, the thickness of the perovskite layer is 400-700nm, preferably 450-500nm; And / or, the thickness of the electron transport layer is 15-30nm, preferably 18-22nm; And / or, the thickness of the passivation layer is 2-20nm, preferably 10-15nm; And / or, the thickness of the transparent conductive film is 60-140nm, preferably 70-85nm.

9. The method for preparing a perovskite / TOPCon tandem solar cell according to claim 7 or 8, characterized in that, The silicon substrate in S1 is an N-type silicon wafer, and the thickness of the silicon wafer is 120-220μm; And / or, the thickness of the tunneling oxide layer in S2 is 0.5-2nm, and the thickness of the doped polysilicon is 30-200nm.

10. The perovskite / TOPCon tandem cell prepared according to the method of any one of claims 7-9, wherein, From bottom to top, it comprises an anti-reflection layer, a passivation layer, a p+ emitter, a silicon substrate, a tunneling oxide layer, a doped polysilicon layer, an interface interconnection layer, a hole transport layer, a perovskite layer, an electron transport layer, a transparent conductive layer, a protective layer, and a metal electrode.

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