Battery pile formation method, laminated battery and method for manufacturing the same

Abstract

The application provides a battery suede forming method, a laminated battery and a preparation method thereof. The battery suede forming method comprises the following steps: providing a crystalline silicon substrate; performing a first texturing treatment on the crystalline silicon substrate to form a first pyramid suede on the top of the crystalline silicon substrate; the first pyramid suede has a first height; performing a first rounding treatment on the first pyramid suede by using ozone and hydrofluoric acid; performing a second rounding treatment on the first pyramid suede by using nitric acid and hydrofluoric acid; performing a second texturing treatment on the crystalline silicon substrate to form a second pyramid suede; the second pyramid suede has a second height, and the second height is smaller than the first height. The rounding treatment exposes the first pyramid suede to the crystal surface of the crystalline silicon substrate which is easier to be textured, thereby facilitating the second texturing treatment to form the second pyramid suede, further reducing the surface energy, facilitating the deposition of a perovskite film through a wet process, and realizing good conformal coverage.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a method for forming a textured surface on a battery, a tandem battery, and a method for preparing the same. Background Technology

[0002] Perovskite-silicon tandem solar cells are a structure that combines crystalline silicon solar cells with perovskite solar cells. Through complementary advantages and synergistic effects, the conversion efficiency is improved, and it is considered to be the next generation of mass-produced photovoltaic technology.

[0003] In traditional techniques, to achieve conformal fabrication of perovskite thin films on the textured surface of crystalline silicon, a two-step process of dry evaporation followed by wet reaction, dry co-evaporation, or a one-step wet coating process can be used. Among these, the wet process can complete the fabrication in one step.

[0004] However, wet processing has extremely high requirements for the morphology of the crystalline silicon surface, requiring a relatively uniform distribution of high surface energy across the entire surface. The large textured surface of crystalline silicon is generally a pyramidal surface, and the surface energy is relatively low at the apex due to its sharp characteristics. During the wet process, it is difficult for the perovskite wet film to completely cover the pyramidal apex in a conformal manner. Summary of the Invention

[0005] Therefore, it is necessary to provide a method for forming a textured surface of a battery, a tandem battery, and a method for preparing the same, which facilitates the use of a one-step wet coating process for perovskite thin films.

[0006] In a first aspect, this application provides a method for forming a textured surface on a battery, comprising the following steps:

[0007] Provide crystalline silicon substrates;

[0008] The crystalline silicon substrate is subjected to a first texturing process to form a first pyramidal texturing surface on the top of the crystalline silicon substrate; the first pyramidal texturing surface has a first height.

[0009] The first pyramid textured surface is subjected to a first rounding treatment using ozone and hydrofluoric acid.

[0010] The first pyramid textured surface is subjected to a second rounding treatment using nitric acid and hydrofluoric acid;

[0011] The crystalline silicon substrate is subjected to a second texturing process to form a second pyramidal textured surface; the second pyramidal textured surface has a second height, which is smaller than the first height.

[0012] In one embodiment, the first height is 4 μm to 6 μm; and / or, the second height is 0.1 μm to 0.4 μm.

[0013] In one embodiment, during the first rounding process, the concentration of ozone introduced is 10 ppm to 60 ppm; and / or,

[0014] The concentration of hydrofluoric acid is 30%~60%; and / or,

[0015] The processing time is 60s~180s.

[0016] In one embodiment, the concentration of nitric acid in the second rounding treatment is 2% to 30%; and / or,

[0017] The concentration of hydrofluoric acid is 0.5% to 5%; and / or,

[0018] The processing time is 60s~180s.

[0019] In one embodiment, the concentration of the nitric acid is 2% to 15%.

[0020] In one embodiment, the first rounding process forms an arc with a radius of not less than 0.8 μm at the top of the first pyramid textured surface.

[0021] In one embodiment, the second rounding process involves forming an arc with a radius of not less than 0.8 μm at the base of the first pyramid textured surface.

[0022] Secondly, this application also provides a method for preparing a tandem battery, comprising the following steps:

[0023] Provide crystalline silicon substrates;

[0024] The crystalline silicon substrate is subjected to a first texturing process to form a first pyramidal texturing surface on the top of the crystalline silicon substrate; the first pyramidal texturing surface has a first height.

[0025] The first pyramid textured surface is subjected to a first rounding treatment using ozone and hydrofluoric acid.

[0026] The first pyramid textured surface is subjected to a second rounding treatment using nitric acid and hydrofluoric acid;

[0027] The crystalline silicon substrate is subjected to a second texturing process to form a second pyramidal textured surface; the second pyramidal textured surface has a second height, which is smaller than the first height;

[0028] A perovskite thin film solution is formed on the crystalline silicon substrate and dried to obtain a tandem battery.

[0029] Thirdly, this application also provides a stacked battery, the stacked battery comprising:

[0030] A crystalline silicon substrate, wherein the upper surface of the crystalline silicon substrate has a first pyramidal textured surface, the top and bottom of the first pyramidal textured surface are at least partially arc-shaped structures, and a second pyramidal textured surface is provided on the arc-shaped structure, wherein the height of the second pyramidal textured surface is less than the height of the first pyramidal textured surface.

[0031] A perovskite thin film, conformally covering the upper surface of the crystalline silicon substrate.

[0032] In one embodiment, the first height of the first pyramid velvet surface is 4 μm to 6 μm; and / or, the second height of the second pyramid velvet surface is 0.1 μm to 0.4 μm.

[0033] In the aforementioned method for forming a textured surface on a battery, a first texturing process is performed on the crystalline silicon substrate to form a first pyramidal textured surface. Then, a first rounding process and a second rounding process are performed on the first pyramidal textured surface. The first rounding process uses ozone and hydrofluoric acid, preferentially rounding the top of the first pyramidal textured surface. The second rounding process uses nitric acid and hydrofluoric acid, preferentially rounding the bottom of the first pyramidal textured surface. This rounding of both the top and bottom of the first pyramidal textured surface exposes the crystal planes of the crystalline silicon substrate for faster texturing, facilitating the second texturing process. In the second texturing process, the rounded areas form a second pyramidal textured surface, further reducing surface energy and facilitating the deposition of perovskite thin films via wet processes, achieving good conformal coverage. Attached Figure Description

[0034] Figure 1 This is a schematic flowchart of a method for forming a textured surface on a battery according to one embodiment.

[0035] Figure 2 This is a schematic diagram of forming a first pyramidal textured surface on a crystalline silicon substrate in one embodiment;

[0036] Figure 3 This is a schematic diagram illustrating the first and second rounding processes in one embodiment.

[0037] Figure 4 This is a schematic diagram of the second texturing process in one embodiment. Detailed Implementation

[0038] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0040] Perovskite-silicon tandem solar cells are poised to become the next generation of mass-produced photovoltaic technology due to their excellent conversion efficiency and low cost. Currently, to achieve conformal perovskite film fabrication on textured surfaces, a two-step process is used: dry evaporation (co-evaporation of single or multiple metal halides such as PbI2, PbBr2, and CsBr) followed by a wet reaction (dissolving organic halides such as FAI and MACl in alcohol solvents); or dry co-evaporation (PbI2, PbBr2, CsI, CsBr, FAI, and MACl). However, both the dry evaporation-wet reaction and dry co-evaporation processes have drawbacks, including high equipment costs, low production reliability, and the lack of self-limiting perovskite composition, resulting in low yield, low conversion efficiency, and poor stability in tandem solar cell production. Therefore, a more reliable perovskite film deposition process is urgently needed for the fabrication of tandem solar cells.

[0041] One approach is to use a one-step wet coating process. However, wet coating processes have extremely high requirements for the morphology of the crystalline silicon surface, requiring a relatively uniform distribution of high surface energy across the entire surface. The textured surface of crystalline silicon is typically a pyramidal surface, with a base angle of approximately 54 degrees and a base width of approximately 2-4 μm. Due to its sharp apex, the surface energy is relatively low, making it difficult for the perovskite wet film to completely conformally cover the pyramid apex during the wet coating process. Secondly, because the base of the pyramid is relatively narrow and has high surface energy, the solvent cannot completely fill the area at the base of the pyramid during the wet coating process, resulting in localized voids that affect charge transport and the mechanical adhesion between the films.

[0042] See Figure 1 , Figure 1 A schematic flowchart of a method for forming a textured surface on a battery is shown in one embodiment. In some embodiments, the method for forming a textured surface on a battery includes the following steps:

[0043] S11 provides a crystalline silicon substrate 10.

[0044] S12, as Figure 2 As shown, Figure 2 A schematic diagram of forming a first pyramidal textured surface on a crystalline silicon substrate is shown in some embodiments. The crystalline silicon substrate 10 is subjected to a first texturing process to form a first pyramidal textured surface 11 on the top of the crystalline silicon substrate 10; the first pyramidal textured surface 11 has a first height.

[0045] For example, before performing the first texturing process on the crystalline silicon substrate 10, the crystalline silicon substrate 10 can be pre-cleaned using a cleaning solution. Optionally, the cleaning solution can be water or the like.

[0046] For example, the first texturing process can use a commercial texturing agent and be etched using an alkaline solution.

[0047] S13, as Figure 3 As shown, Figure 3 This is a schematic diagram illustrating the first and second rounding treatments of crystalline silicon in one embodiment. The first rounding treatment is performed on the first pyramidal textured surface 11 using ozone and hydrofluoric acid.

[0048] The apex region of the pyramid has a low surface energy due to its sharp characteristics. In the texturing process of crystalline silicon, the etching rate of the Si (100) crystal plane is more than ten times greater than that of the Si (111) crystal plane. Therefore, the texturing process forms a pyramid structure. However, in some cases, the size of the first pyramid textured surface 11 is too large to maximize the reduction of surface energy. Here, "100" and "111" represent the crystal plane index of the Si surface.

[0049] For example, the top of the first pyramid velvet surface 11 refers to its top tip position. By performing a first rounding treatment on its top tip, a portion of the tip can be removed to form a rounded corner at the top of the first pyramid velvet surface.

[0050] In this step, ozone and hydrofluoric acid are used for combined etching. This step prioritizes etching the top region of the pyramid to round the top of the pyramid, thereby exposing the Si (100) crystal plane of the crystalline silicon substrate, which facilitates the subsequent second texturing process.

[0051] Specifically, the principle of the first rounding treatment is shown in the following reaction equation: the silicon at the top of the pyramid is converted into silicon oxide by ozone, and then the silicon oxide is removed by hydrofluoric acid: 6Si + 2O3 → 3SiO2; 4HF + SiO2 → SiF4↑ + 2H2O.

[0052] S14, as Figure 3 As shown, the first pyramid textured surface 11 is subjected to a second rounding treatment using nitric acid and hydrofluoric acid.

[0053] Due to the high surface energy at the base of the pyramid, the solution and air compete for energy during the subsequent wet coating process of the perovskite film. Small air bubbles are prone to remain at the bottom, and the solvent of the perovskite film cannot completely fill the area at the base of the pyramid, resulting in localized pores in this location. This affects charge transport and leads to lower mechanical adhesion between the film and crystalline silicon.

[0054] In this step, the base of the pyramid is etched preferentially using a combination of nitric acid and hydrofluoric acid to achieve a rounded effect on the base of the pyramid.

[0055] Specifically, the principle of the second rounding treatment is as follows: first, the silicon at the bottom of the pyramid is oxidized to silicon oxide by nitric acid, and then the silicon oxide is removed by hydrofluoric acid to achieve rounding treatment and expose the Si (100) crystal plane of the crystalline silicon substrate: Si + 4HNO3 → SiO2 + 4NO2 + 2H2O; 4HF + SiO2 → SiF4↑ + 2H2O.

[0056] S15, such as Figure 4 As shown, Figure 4 A schematic diagram of the second texturing process is shown in one embodiment. The crystalline silicon substrate is subjected to a second texturing process to form a second pyramidal textured surface 12; the second pyramidal textured surface 12 has a second height, which is smaller than the first height.

[0057] After the top of the first pyramid textured surface 11 is rounded by the first rounding process and the bottom of the first pyramid textured surface 11 is rounded by the second rounding process, the Si (100) crystal surface of the crystalline silicon substrate 10 is exposed, which facilitates the formation of a new second pyramid textured surface 12 on the exposed Si (100) crystal surface. In the second texturing process, the pyramid structure formed is smaller than the pyramid structure formed by the first texturing process, that is, the second height of the second pyramid textured surface is smaller than the first height of the first pyramid textured surface.

[0058] This further reduces the surface energy of the top and bottom of the first pyramid textured surface, facilitating the subsequent formation of perovskite thin films.

[0059] In the above-described method for forming a textured surface on a battery, a first texturing process is first performed on the crystalline silicon substrate 10 to form a first pyramidal textured surface 11. Then, a first rounding process and a second rounding process are performed on the first pyramidal textured surface 11. The first rounding process uses ozone and hydrofluoric acid, preferentially rounding the top of the first pyramidal textured surface. The second rounding process uses nitric acid and hydrofluoric acid, preferentially rounding the bottom of the first pyramidal textured surface. This rounding of both the top and bottom of the first pyramidal textured surface exposes the crystal planes of the crystalline silicon substrate for faster texturing, facilitating the second texturing process. In the second texturing process, the rounded areas form a second pyramidal textured surface 12, further reducing surface energy and facilitating the deposition of perovskite thin films via wet processes, achieving good conformal coverage.

[0060] In some embodiments, the first height is 4 μm to 6 μm. In some embodiments, the second height is 0.1 μm to 0.4 μm.

[0061] For example, the first height of the first pyramid textured surface 11 refers to the vertical height from the base to the top of the pyramid, and the value of the first height can be 4μm, 4.5μm, 5μm, 5.5μm, or 6μm, etc. The second height of the second pyramid textured surface 12 refers to the vertical height from the base to the top of the pyramid, and the value of the second height can be 0.1μm, 0.2μm, 0.3μm, or 0.4μm.

[0062] In traditional techniques, the height of the pyramidal textured surface is 2μm~4μm, which cannot form good conformal coverage in the wet process of preparing perovskite thin films. However, by combining the first pyramidal textured surface 11 and the second pyramidal textured surface 12, a small pyramidal structure is constructed on the large pyramidal structure, which effectively reduces the surface energy and improves the conformal coverage of the perovskite thin film.

[0063] In some embodiments, during the first rounding treatment, the concentration of ozone introduced is 10 ppm to 60 ppm; and / or, the concentration of hydrofluoric acid is 30% to 60%; and / or, the treatment time is 60 s to 180 s.

[0064] For example, in the first rounding treatment, the concentration of ozone introduced can be, but is not limited to, 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, or 60 ppm. The concentration of hydrofluoric acid can be, but is not limited to, 30%, 35%, 40%, 45%, 50%, 55%, or 60%. The treatment time can be, but is not limited to, 60 s, 80 s, 100 s, 120 s, 140 s, 160 s, or 180 s.

[0065] In some embodiments, in the second rounding treatment, the concentration of nitric acid is 2% to 30%; and / or the concentration of hydrofluoric acid is 0.5% to 5%; and / or the treatment time is 60s to 180s.

[0066] For example, in the second rounding treatment, the concentration of nitric acid can be, but is not limited to, 2%, 5%, 8%, 10%, 15%, 20%, 25%, or 30%. The concentration of hydrofluoric acid can be, but is not limited to, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%. The treatment time can be, but is not limited to, 60s, 80s, 100s, 120s, 140s, 160s, or 180s. Further, the concentration of nitric acid is 2% to 15%.

[0067] In some embodiments, the first rounding process forms an arc with a radius of not less than 0.8 μm at the top of the first pyramid textured surface 11. For example, the radius of the top of the first pyramid textured surface 11 is 0.8 μm to 5 μm. Further, the radius of the top of the first pyramid textured surface 11 can be 0.8 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, or 5 μm, etc.

[0068] In some embodiments, during the second rounding process, the base of the first pyramid textured surface 11 is formed with an arc having a radius of not less than 0.8 μm. For example, the radius of the base of the first pyramid textured surface 11 is 0.8 μm to 5 μm. Further, the radius of the base of the first pyramid textured surface can be 0.8 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, or 5 μm, etc.

[0069] In some embodiments, a method for preparing a stacked battery includes the following steps.

[0070] S21 provides a crystalline silicon substrate 10.

[0071] S22, a first texturing process is performed on the crystalline silicon substrate 10 to form a first pyramid textured surface 11 on the top of the crystalline silicon substrate 10; the first pyramid textured surface 11 has a first height.

[0072] S23, the first pyramid velvet surface 11 is subjected to a first rounding treatment using ozone and hydrofluoric acid.

[0073] S24, the first pyramid textured surface 11 is subjected to a second rounding treatment using nitric acid and hydrofluoric acid.

[0074] S25, a second texturing process is performed on the crystalline silicon substrate to form a second pyramid textured surface 12; the second pyramid textured surface 12 has a second height, which is smaller than the first height.

[0075] S26, a perovskite thin film solution is formed on a crystalline silicon substrate, and dried to obtain a tandem cell.

[0076] In step S26, a wet process is used to form a perovskite thin film, that is, a perovskite thin film solution is first deposited on a crystalline silicon substrate, and after drying, a conformal perovskite thin film is formed to obtain a tandem solar cell.

[0077] For example, the perovskite thin film solution can be a solution of FACsPbIBrCl, FAMACsPbIBrCl, FACsDMAPbIBrCl, CsDMAPbIBrCl, FACsPbIBr, FAMACsPbSnIbIBr, FACsDMAPbIBr, or CsDMAPbIBr.

[0078] In some embodiments, this application also provides a stacked battery, the stacked battery comprising: a crystalline silicon substrate 10, the upper surface of the crystalline silicon substrate 10 having a first pyramidal textured surface 11, the top and bottom of the first pyramidal textured surface 11 being at least partially arc-shaped structures, the arc-shaped structures having a second pyramidal textured surface 12, the height of the second pyramidal textured surface 12 being less than the height of the first pyramidal textured surface 11; and a perovskite thin film conformally covering the upper surface of the crystalline silicon substrate 10.

[0079] In some embodiments, the first height of the first pyramidal textured surface 11 is 4 μm to 6 μm; and / or, the second height of the second pyramidal textured surface 12 is 0.1 μm to 0.4 μm. Exemplarily, the first height of the first pyramidal textured surface 11 refers to the vertical height from the base to the top of the pyramid, and the value of the first height can be 4 μm, 4.5 μm, 5 μm, 5.5 μm, or 6 μm, etc. The second height of the second pyramidal textured surface 12 refers to the vertical height from the base to the top of the pyramid, and the value of the second height can be 0.1 μm, 0.2 μm, 0.3 μm, or 0.4 μm.

[0080] The following are specific examples.

[0081] Example 1

[0082] S11 provides a crystalline silicon substrate.

[0083] S12, a commercial texturing agent (Xi'an Lanqiao New Energy Technology Co., Ltd., LQ6SB01) is used to perform a first texturing treatment on the crystalline silicon substrate to form a first pyramid textured surface on the top of the crystalline silicon substrate; the first height of the first pyramid textured surface is 5μm.

[0084] S13, the first pyramid textured surface is subjected to a first rounding treatment using ozone and hydrofluoric acid, wherein the ozone concentration is 40 ppm, the hydrofluoric acid concentration is 45%, and the treatment time is 120 s.

[0085] S14, the first pyramid textured surface is subjected to a second rounding treatment using nitric acid and hydrofluoric acid, wherein the concentration of nitric acid is 15%, the concentration of hydrofluoric acid is 2%, and the treatment time is 120s.

[0086] S15, a second texturing process is performed on the crystalline silicon substrate using a commercial texturing agent (Xi'an Lanqiao New Energy Technology Co., Ltd., LQ6S) to form a second pyramid textured surface, the height of which is 0.2μm.

[0087] The fabrication method of the tandem solar cell is as follows: a perovskite thin film solution is deposited on the textured surface of the prepared solar cell, and after drying, a perovskite thin film is formed on crystalline silicon to obtain the tandem solar cell. The perovskite thin film solution is FA. 0.95 Cs 0.05PbI3 solution.

[0088] Example 2

[0089] The preparation method of Example 2 is basically the same as that of Example 1, except that in step S12, the first height of the first pyramid textured surface is 4 μm.

[0090] Example 3

[0091] The preparation method of Example 3 is basically the same as that of Example 1, except that in step S12, the first height of the first pyramid textured surface is 6 μm.

[0092] Example 4

[0093] The preparation method of Example 4 is basically the same as that of Example 1, except that in step S13, the ozone concentration is 10 ppm and the hydrofluoric acid concentration is 60%.

[0094] Example 5

[0095] The preparation method of Example 5 is basically the same as that of Example 1, except that in step S13, the ozone concentration is 60 ppm and the hydrofluoric acid concentration is 30%.

[0096] Example 6

[0097] The preparation method of Example 6 is basically the same as that of Example 1, except that in step S14, the concentration of nitric acid is 2 ppm and the concentration of hydrofluoric acid is 5%.

[0098] Example 7

[0099] The preparation method of Example 7 is basically the same as that of Example 1, except that in step S14, the concentration of nitric acid is 30 ppm and the concentration of hydrofluoric acid is 0.5%.

[0100] Example 8

[0101] The preparation method of Example 8 is basically the same as that of Example 1, except that in step S15, the first height of the second pyramid textured surface is 0.1 μm.

[0102] Example 9

[0103] The preparation method of Example 9 is basically the same as that of Example 1, except that in step S15, the first height of the second pyramid textured surface is 0.4 μm.

[0104] Comparative Example 1

[0105] The preparation method of Comparative Example 1 is basically the same as that of Example 1, except that steps S12 to S15 are not performed.

[0106] The preparation methods and process parameters for Examples 1-9 and Comparative Example 1 are listed in Table 1 below:

[0107] Table 1

[0108]

[0109] The battery textured surfaces prepared in Examples 1-9 and Comparative Example 1 were subjected to performance tests, and the test results are shown in Table 2 below.

[0110] The test conditions or test standards for each performance test item are as follows.

[0111] The water droplet angle is the contact angle of a perovskite solution on a silicon wafer after texturing and cleaning. The test conditions for the water droplet angle are: the perovskite precursor solution is dropped onto the surface of the silicon wafer, and due to the surface tension of the liquid, an angle is formed between the liquid and the solid. The test is conducted at the solid-liquid-gas three-phase interface, where the two tangents of the gas-liquid interface and the solid-liquid interface trap the liquid phase, forming an angle.

[0112] The reflectivity test conditions were as follows: the tandem solar cell sample was held in an 8° angled porous integrating sphere and illuminated by an incident light beam. The light was reflected multiple times by the inner wall of the sphere until it was detected by the photodetector. The 8° angled porous integrating sphere is a sphere with a special angle and porous structure. The photodetector was positioned at 8°. The incident light beam entered the integrating sphere through the porous structure, and the light was reflected multiple times by the inner wall of the sphere, allowing the scattered light to uniformly illuminate the tandem solar cell sample from various angles until it was detected by the photodetector. The reflectivity of the tandem solar cell sample in the 300nm~1200nm wavelength range was measured, and the average value from 500nm~1000nm was taken.

[0113] EFF refers to the conversion efficiency of a solar cell made from a texturized and cleaned silicon wafer. The EFF test conditions are as follows: an artificial light source simulating the sun is prepared, with light intensity and spectrum calibrated to AM1.5G; the temperature of the tandem solar cell sample is controlled within the range of 25±2℃; and the solar cell's photoluminescence (IV) curve is tracked and obtained by changing the variable resistance at both ends of the cell and recording the voltage and current at the cell terminals. Where V... OC (Open-circuit voltage) is the voltage at which zero current is applied, I SC (Short-circuit current) is the current at zero voltage, EFF is the maximum value of the product of current and voltage, i.e., the maximum output power, and FF is the ratio of the maximum output power to the product of the short-circuit current and the open-circuit voltage.

[0114] Table 2

[0115]

[0116] As shown in Table 2 above, compared with Comparative Example 1, Examples 1-9 have higher FF and EFF without a significant decrease in reflectivity. This indicates that the perovskite film layer of Examples 1-9 has better coverage on the silicon wafer pyramid surface, proving that the textured surface formation method provided by the present invention can effectively improve the yield of tandem solar cell fabrication, thereby bringing about optimization in terms of conversion efficiency and electrical performance.

[0117] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0118] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for forming a textured surface on a battery, characterized in that, Includes the following steps: Provide crystalline silicon substrates; The crystalline silicon substrate is subjected to a first texturing process to form a first pyramidal texturing surface on the top of the crystalline silicon substrate; the first pyramidal texturing surface has a first height. The first pyramid textured surface is subjected to a first rounding treatment using ozone and hydrofluoric acid. The first pyramid textured surface is subjected to a second rounding treatment using nitric acid and hydrofluoric acid; The crystalline silicon substrate is subjected to a second texturing process to form a second pyramidal textured surface; the second pyramidal textured surface has a second height, which is smaller than the first height.

2. The method according to claim 1, characterized in that, The first height is 4μm to 6μm; and / or the second height is 0.1μm to 0.4μm.

3. The method according to claim 1, characterized in that, In the first rounding treatment, the concentration of ozone introduced is 10ppm to 60ppm; and / or, The concentration of hydrofluoric acid is 30%~60%; and / or, The processing time is 60s~180s.

4. The method according to claim 3, characterized in that, In the second rounding treatment, the concentration of nitric acid is 2% to 30%; and / or, The concentration of hydrofluoric acid is 0.5% to 5%; and / or, The processing time is 60s~180s.

5. The method according to claim 4, characterized in that, The concentration of the nitric acid is 2% to 15%.

6. The method according to claim 1, characterized in that, In the first rounding process, the top of the first pyramid textured surface is formed with an arc with a radius of not less than 0.8 μm.

7. The method according to claim 1, characterized in that, In the second rounding process, the base of the first pyramid textured surface is formed with an arc having a radius of not less than 0.8 μm.

8. A method for preparing a stacked battery, characterized in that, Includes the following steps: Provide crystalline silicon substrates; The crystalline silicon substrate is subjected to a first texturing process to form a first pyramidal texturing surface on the top of the crystalline silicon substrate; the first pyramidal texturing surface has a first height. The first pyramid textured surface is subjected to a first rounding treatment using ozone and hydrofluoric acid. The first pyramid textured surface is subjected to a second rounding treatment using nitric acid and hydrofluoric acid; The crystalline silicon substrate is subjected to a second texturing process to form a second pyramidal textured surface; the second pyramidal textured surface has a second height, which is smaller than the first height; A perovskite thin film solution is formed on the crystalline silicon substrate and dried to obtain a tandem battery.

9. A stacked battery, characterized in that, The stacked battery includes: A crystalline silicon substrate, wherein the upper surface of the crystalline silicon substrate has a first pyramidal textured surface, the top and bottom of the first pyramidal textured surface are at least partially arc-shaped structures, and a second pyramidal textured surface is provided on the arc-shaped structure, wherein the height of the second pyramidal textured surface is less than the height of the first pyramidal textured surface. A perovskite thin film, conformally covering the upper surface of the crystalline silicon substrate.

10. The stacked battery according to claim 9, characterized in that, The first height of the first pyramid velvet surface is 4μm to 6μm; and / or the second height of the second pyramid velvet surface is 0.1μm to 0.4μm.

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