A solar cell cutting edge passivation film layer and method thereof

Abstract

The present invention relates to a method for passivating the cut edge of a solar cell, which uses hot wire chemical vapor deposition to form a passivation film layer, comprising: exposing the cut edge of the cell and facing the hot wire; passing an electric current through the hot wire to heat it, and passing H2 to perform hydrogen etching; maintaining heating, passing SiH4 at a first pressure, and simultaneously passing SiH4 and H2 while maintaining the first pressure to obtain an a-Si:H film layer; maintaining heating, and simultaneously passing SiH4 and NH3 at a second pressure to deposit SiN on the a-Si:H film layer. x :H film layer to form a passivation composite film layer on the cutting edge, or SiH4, NH3, H2 and O2 are introduced simultaneously under a second pressure to deposit SiN on the a-Si:H film layer. x O y The present invention provides a coating technology with low defect state density, high passivation performance, excellent weather resistance, and high optical transmittance, and a simple process, high cost-effectiveness, and scalable application.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cell coating, and more particularly, relates to a solar cell cut edge passivation film layer and a method thereof. Background Art

[0002] In the photovoltaic industry, mainstream cell production currently utilizes large-sized silicon wafers, such as 182mm*182mm and 210mm*210mm. To increase module power, the industry generally utilizes half-cell technology, cutting the entire cell into half-cells using lasers and other methods. In addition to cutting a single cell into two or three sub-cells, it can also be cut into applications with even more sub-cells, known as shingled cells. However, in practice, laser cutting has been found to cause severe laser damage and defects along the cutting edges. These damage and defects serve as effective recombination centers for charge carriers. Surface recombination on solar cells reduces the number of surface-excited charge carriers, leading to power loss and a significant negative impact on the solar cell's electrical performance.

[0003] To solve this problem, after laser cutting, passivation coating technology is currently mainly used to repair the edge. Passivation coating refers to forming a passivation film on the surface of the cell by deposition, thereby reducing surface defects and recombination centers, reducing carrier recombination rate, and improving photoelectric conversion efficiency. The coating materials currently reported include amorphous silicon (a-Si:H), silicon nitride (SiN x ), silicon dioxide (SiO2), aluminum oxide (Al2O3), titanium oxide (TiO2), etc. Passivation coating technologies reported include plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), low pressure chemical vapor deposition (LPCVD), etc.

[0004] Different edge passivation coating materials have their own advantages and disadvantages. For example, amorphous silicon (a-Si:H) is the best passivation material at present because it can effectively reduce the defect state density on the semiconductor surface and reduce carrier recombination. However, a-Si:H film is easily reacted with water vapor, oxygen, etc. when exposed to the atmosphere, which leads to a decrease in passivation effect. Silicon dioxide (SiO2) has excellent insulation properties, chemical stability and good surface passivation effect, but its mechanical strength is low and it is easily damaged. Silicon nitride (SiN x ) and silicon oxynitride (SiN x O y) has good insulation and chemical stability, and excellent anti-reflection properties, but its passivation effect on certain types of surface defects is limited and its performance degrades at high temperatures. Aluminum oxide (Al2O3) has excellent surface passivation quality, good thermal stability and chemical stability, but its preparation process is complex, the cost is high, and the deposition rate is slow, which affects production efficiency. Titanium oxide (TiO2) has excellent chemical stability, weather resistance and light absorption efficiency, but its passivation effect is not as good as aluminum oxide (Al2O3), and its preparation process is complex and the cost is high.

[0005] PECVD passivation coating technology has the advantages of high-quality coating, high deposition rate and the ability to deposit a variety of materials in solar cell manufacturing. However, the traditional tubular PECVD technology is used to prepare a-Si:H, SiN x :H and SiN x O y :H series films require a high temperature of about 400°C, which will not only destroy the a-Si:H film deposited on the surface of the HJT battery (heterojunction battery), but also cause uneven film layers or defects. Although the use of plate-type PECVD technology can avoid the high temperature problem, its equipment is expensive, the cost-effectiveness is not high, and it is difficult to apply on a large scale. ALD passivation coating technology has extremely high uniformity, precise thickness control and excellent passivation effect. However, its disadvantages such as slow deposition rate, high equipment cost and limited production capacity also limit its application in large-scale production. LPCVD passivation coating technology has the advantages of high-quality thin films, good step coverage and high deposition rate. However, its high-temperature process (more suitable for traditional battery structures that are not sensitive to temperature or the front passivation layer of high-efficiency batteries), high equipment cost and film stress problems also limit its application in large-scale production.

[0006] Therefore, there is an urgent need to design a method for passivating the cut edges of solar cells that can overcome the above-mentioned defects. Summary of the Invention

[0007] In response to the defects of the above-mentioned various types of solar cell coating materials and coating technologies, the purpose of the present invention is to provide a method for passivating the cut edges of solar cells. This method adopts hot wire chemical vapor deposition (HoFCVD) coating technology, which can solve the problems of high coating temperature and insufficient comprehensive performance of film materials faced by the current passivation of cut edges of solar cells.

[0008] In order to solve the above technical problems or achieve the above objectives, the present invention adopts the following technical solutions:

[0009] According to one aspect of the present invention, a method for passivating the cut edge of a solar cell is provided. The method uses a hot wire chemical vapor deposition device to deposit a passivation film layer on the cut edge, comprising the following steps:

[0010] Expose the cut edge of the cell and align it with the hot wire;

[0011] Pass an electric current through the hot wire to heat it, and then pass H2 into it to perform hydrogen etching on the surface of the silicon wafer;

[0012] Keep the hot wire heated by current, introduce SiH4 at a first pressure, then maintain the first pressure while introducing SiH4 and H2 simultaneously, complete the growth of the amorphous silicon layer at room temperature to 200°C, and obtain an a-Si:H film layer;

[0013] Continue to keep the hot wire heated by current, and at the second pressure, introduce SiH4 and NH3 at the same time to complete the growth of silicon nitride layer at room temperature to 200℃, and deposit SiN on the a-Si:H film layer. x :H film layer, thereby forming a passivation composite film layer of the cutting edge, or under the second pressure, SiH4, NH3, H2 and O2 are introduced at the same time, and the silicon nitride oxide layer is grown at room temperature to 200 ° C, and SiN is deposited on the a-Si:H film layer. x O y :H film layer, thereby forming a passivation composite film layer on the cutting edge.

[0014] In one embodiment of the present invention, the current supplied to the hot wire is ≥30A, and the flow rate of H2 supplied is 200-1000 sccm.

[0015] In one embodiment of the present invention, the first pressure is ≤3 Pa, the flow ratio of SiH4 and H2 introduced is SiH4:H2≥1:1, and the thickness of the amorphous silicon layer is 5-30 nm.

[0016] In one embodiment of the present invention, when SiN is deposited on the a-Si:H film layer, x :H film layer, the second pressure ≤5Pa, the flow ratio of SiH4 and NH3 into NH3:SiH4 ≥2:1, and the thickness of the silicon nitride layer is 1-100nm.

[0017] In one embodiment of the present invention, when SiN is deposited on the a-Si:H film layer, x O y :H film layer, the second pressure ≤5Pa, the flow ratio of SiH4, NH3, H2 and O2 introduced is NH3:SiH4≥2:1, the flow ratio H2:SiH4≥1:1, the flow ratio O2:SiH4≥1:1, and the thickness of the silicon nitride oxide layer is 1-100nm.

[0018] In one embodiment of the present invention, when depositing SiN x :H film layer, the obtained SiN x :H film has a refractive index of 1.7-2.1 and is continuously adjustable; when depositing SiNx O y :H film layer, the obtained SiN x O y :The refractive index of the H film layer is ≤1.5.

[0019] According to another aspect of the present invention, a method for passivating the cut edge of a solar cell is provided. The method uses a hot wire chemical vapor deposition device to deposit a passivation film layer on the cut edge, comprising the following steps:

[0020] Expose the cut edge of the cell and align it with the hot wire;

[0021] Pass an electric current through the hot wire to heat it, and pass H2 into it to perform hydrogen etching on the surface of the silicon wafer;

[0022] Keep the hot wire flowing with current for heating, introduce SiH4 at a first pressure, then maintain the first pressure while introducing SiH4 and H2 at the same time, complete the growth of the amorphous silicon layer at room temperature to 200°C, and obtain an a-Si:H passivation film layer.

[0023] According to another aspect of the present invention, a method for passivating the cut edge of a solar cell is provided. The method uses a hot wire chemical vapor deposition device to deposit a passivation film layer on the cut edge, comprising the following steps:

[0024] Expose the cut edge of the cell and align it with the hot wire;

[0025] Pass an electric current through the hot wire to heat it, and pass H2 into it to perform hydrogen etching on the surface of the silicon wafer;

[0026] Keep the hot wire heated by current, and at the second pressure, introduce SiH4 and NH3 at the same time to complete the growth of silicon nitride layer at room temperature to 200℃ to obtain SiN x :H passivation film layer.

[0027] According to another aspect of the present invention, there is provided a solar cell cut edge passivation film layer prepared by the above-mentioned solar cell cut edge passivation method, comprising:

[0028] a-Si:H film layer;

[0029] SiN deposited on a-Si:H film x :H film or SiN x O y :H film layer.

[0030] According to another aspect of the present invention, there is provided a solar cell cut edge passivation film layer prepared by the above-mentioned solar cell cut edge passivation method, comprising an a-Si:H passivation film layer or a SiN x :H passivation film layer.

[0031] The technical solution provided by the present invention has the following advantages compared with the prior art:

[0032] (1) The present invention uses HoFCVD equipment or technology to prepare passivation films on the cutting edges of solar cells, and can successfully prepare a-Si:H films, SiN films, and other passivation films within the range of room temperature to 200°C. x :H film or SiN x O y :H film layer, avoiding damage to the intrinsic a-Si:H film layer, retaining the intrinsic a-Si:H film layer's advantages of low defect state density, low carrier recombination, and excellent passivation performance, and solving the problem of high-temperature coating destroying the deposited a-Si:H film on the surface of the HJT battery and causing uneven film layer or defects.

[0033] (2) The solar cell passivation a-Si:H+SiN in the present invention x :H or a-Si:H+SiN x O y :H composite film combines the advantages of low defect state density, low carrier recombination, and excellent passivation performance of a-Si:H film and SiN x :H / SiN x O y :H film has good thermal stability and chemical stability, which enables the solar cell passivation film layer to have low defect density, high passivation performance and excellent weather resistance.

[0034] (3) The film layer prepared by the HoFCVD device or technology in the present invention has a low refractive index: for example, SiN x :H film layer 1.7-2.1 continuously adjustable, SiN x O y :H film layer can be as low as 1.5, the film layer has good density and does not affect the light transmittance.

[0035] (4) The present invention provides a film layer with excellent comprehensive performance of low defect state density, high passivation performance, excellent weather resistance, and high optical transmittance, and a coating technology with simple process, high cost performance, and scalable application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the description of the embodiments or the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0038] Figure 1 A schematic flow chart of a method for passivating cut edges of solar cells provided by one embodiment of the present invention is shown;

[0039] Figure 2 A schematic flow chart of a method for passivating cut edges of solar cells provided by another embodiment of the present invention is shown;

[0040] Figure 3 A schematic flow chart of a method for passivating cut edges of solar cells provided by another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0041] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the embodiments of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features therein can be combined with each other without conflict.

[0042] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways than those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0043] like Figure 1 As shown, one embodiment of the present invention provides a method for passivating the cut edge of a solar cell. The method uses a hot wire chemical vapor deposition device to deposit a passivation film layer on the cut edge, comprising the following steps:

[0044] S10: Expose the cut edge of the cell and align it with the hot wire;

[0045] S11: Pass current through the hot wire to heat it, and then pass H2 into it to perform hydrogen etching on the surface of the silicon wafer;

[0046] S12: Keep the hot wire heated by current, introduce SiH4 at a first pressure, then maintain the first pressure while introducing SiH4 and H2 simultaneously, complete the growth of the amorphous silicon layer at room temperature to 200° C., and obtain an a-Si:H film layer;

[0047] S13: Continue to keep the hot wire heated by current, and at the second pressure, introduce SiH4 and NH3 at the same time to complete the growth of the silicon nitride layer at room temperature to 200 ° C, and deposit SiN on the a-Si:H film layer.x :H film layer, thereby forming a passivation composite film layer of the cutting edge, or under the second pressure, SiH4, NH3, H2 and O2 are introduced at the same time, and the silicon nitride oxide layer is grown at room temperature to 200 ° C, and SiN is deposited on the a-Si:H film layer. x O y :H film layer, thereby forming a passivation composite film layer on the cutting edge.

[0048] Through the above technical solution of the present invention, the present invention uses HoFCVD equipment or technology for the preparation of passivation film layer on the cutting edge of solar cell, and can successfully prepare a-Si:H film, SiN x :H film or SiN x O y :H film layer, avoiding damage to the intrinsic a-Si:H film layer, retaining the intrinsic a-Si:H film layer's low defect state density, low carrier recombination, and excellent passivation performance advantages, and solving the problem of high-temperature coating damaging the a-Si:H film deposited on the surface of the HJT cell and causing uneven film layers or defects. The solar cell passivated a-Si:H+SiN prepared in the present invention x :H or a-Si:H+SiN x O y The :H composite film layer combines the low defect state density, low carrier recombination, and excellent passivation performance advantages of the a-Si:H film layer with the good thermal stability and chemical stability advantages of the SiNx:H / SiNxOy:H film layer, achieving low defect state density, high passivation performance and excellent weather resistance for the passivation film layer of solar cells.

[0049] In the technical solution shown in the above embodiment of the present invention, in step S11, the current passed through the hot wire is ≥30A, preferably 32A; the flow rate of H2 passed through is 200-1000sccm, preferably 600sccm.

[0050] In the technical solution shown in the above embodiment of the present invention, in step S12, the first pressure is ≤3Pa, preferably 2Pa; the flow ratio of SiH4 and H2 introduced is SiH4:H2≥1:1, preferably the flow ratio SiH4:H2=2:1; the thickness of the amorphous silicon layer is 5-30nm, preferably 20nm.

[0051] In the technical solution shown in the above embodiment of the present invention, in step S13, when SiN is deposited on the a-Si:H film layer, x :H film layer, the second pressure ≤5Pa, preferably 4Pa; the flow ratio of SiH4 and NH3 introduced is NH3:SiH4≥2:1, preferably NH3:SiH4=3:1; the thickness of the silicon nitride layer is 1-100nm, preferably 50nm.

[0052] In the technical solution shown in the above embodiment of the present invention, in step S13, when SiN is deposited on the a-Si:H film layer, x O y :H film layer, the second pressure ≤5Pa, preferably 4Pa; the flow ratio of SiH4, NH3, H2 and O2 introduced is NH3:SiH4≥2:1, the flow ratio H2:SiH4≥1:1, the flow ratio O2:SiH4≥1:1, preferably the flow ratio NH3:SiH4=3:1, the flow ratio H2:SiH4=2:1, the flow ratio O2:SiH4=2:1; the thickness of the silicon oxynitride layer is 1-100nm, preferably 50nm.

[0053] In the technical solution shown in the above embodiment of the present invention, in step S13, when depositing SiN x :H film layer, the obtained SiN x :H film has a refractive index of 1.7-2.1 and is continuously adjustable. x O y :H film layer, the obtained SiN x O y :H film refractive index ≤ 1.5. The film prepared by using HoFCVD equipment or technology in the present invention has a low refractive index: for example, SiN x :H film layer 1.7-2.1 continuously adjustable, SiN x O y :H film can be as low as 1.5, the film has good density and does not affect the light transmittance. Therefore, when the SiN film is formed by passivation, the obtained x :H film or SiN x O y The refractive index of the a-Si:H film layer is low and will not affect the light entering the a-Si:H film layer.

[0054] like Figure 2 As shown, another embodiment of the present invention provides a method for passivating the cut edge of a solar cell, the method using a hot wire chemical vapor deposition device to deposit a passivation film layer on the cut edge, comprising the following steps:

[0055] S20: Expose the cut edge of the cell and align it with the hot wire;

[0056] S21: passing current through the hot wire to heat it, and passing H2 to perform hydrogen etching on the surface of the silicon wafer;

[0057] S22: Keep the hot wire flowing with current for heating, introduce SiH4 at a first pressure, then maintain the first pressure while introducing SiH4 and H2 at the same time, complete the growth of the amorphous silicon layer at room temperature to 200°C, and obtain an a-Si:H passivation film layer.

[0058] The present invention utilizes HoFCVD coating technology to successfully produce an a-Si:H passivation film at temperatures ranging from room temperature to 200°C. This a-Si:H passivation film can reduce carrier recombination. Furthermore, the present invention features a simple process, high cost-effectiveness, and scalable application.

[0059] like Figure 3 As shown, another embodiment of the present invention provides a method for passivating the cut edge of a solar cell, the method using a hot wire chemical vapor deposition device to deposit a passivation film layer on the cut edge, comprising the following steps:

[0060] S30: Exposing the cut edge of the cell and aligning it with the hot wire;

[0061] S31: passing an electric current through the hot wire to heat it, and passing H2 to perform hydrogen etching on the surface of the silicon wafer;

[0062] S32: Keep the hot wire heated by current, and at the second pressure, introduce SiH4 and NH3 at the same time to complete the growth of the silicon nitride layer at room temperature to 200 ° C to obtain SiN x :H passivation film layer.

[0063] The present invention adopts HoFCVD coating technology, which can successfully prepare SiN x :H film and prepared SiN x The H film has a low refractive index and good film density, which does not affect light transmittance. Furthermore, the process of the present invention is simple, cost-effective, and can be applied on a large scale.

[0064] In addition, an embodiment of the present invention provides a method of Figure 1 The solar cell cut edge passivation film layer prepared by the solar cell cut edge passivation method shown includes:

[0065] a-Si:H film layer;

[0066] SiN deposited on a-Si:H film x :H film or SiN x O y :H film layer.

[0067] In addition, an embodiment of the present invention further provides a method for Figure 2 As shown or Figure 3 The solar cell cutting edge passivation film layer prepared by the solar cell cutting edge passivation method shown in the figure includes a-Si:H passivation film layer or SiN x :H passivation film layer.

[0068] The above technical solution of the present invention is described in detail below through specific embodiments.

[0069] The solar cell edge passivation film layer designed in the embodiment of the present invention is composed of a multi-layer structure or a single-layer structure.

[0070] In one embodiment of the present invention, the multilayer structure includes an a-Si:H film layer and a SiN x :H film layer, or including a-Si:H film layer and SiN x O y :H film layer.

[0071] When the a-Si:H film is exposed to the atmosphere, it is easy to react with water vapor, oxygen, etc., which will lead to a decrease in the passivation effect. If a layer of weather-resistant and low-refractive-index film is composited on its surface to protect it, it can not only retain the excellent passivation performance of the intrinsic a-Si:H film, but also use the composite film structure to prevent the intrinsic a-Si:H film from reacting with water vapor, oxygen, etc. in the atmosphere. x :H film or SiN x O y :H film layer has good insulation and chemical stability, excellent anti-reflection performance, so the present invention adopts a-Si:H film layer and SiN x :H film, or a-Si:H film and SiN x O y : Composite film layer composed of H film layer.

[0072] In the above embodiment, the composite film layer is prepared using HoFCVD (hot wire chemical vapor deposition) equipment or technology. The specific process steps are as follows:

[0073] Step 1: Stack multiple solar cells and install them in a fixture, with the exposed edges of the cells facing the outside of the fixture mouth and no obvious gaps between the cells. The fixture is placed in the cavity of the HoFCVD equipment, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0074] Step 2: The stacked cells are placed in the HoFCVD equipment, the hot wire maintains a certain current (≥30A), and then a certain amount of H2 (200-1000sccm) is introduced to perform hydrogen etching on the silicon wafer surface.

[0075] Step 3: The stacked cells are placed in the HoFCVD equipment, the hot wire maintains a certain current (≥30A), the pressure is controlled to be ≤3Pa, SiH4 is introduced, the pressure is continued to be controlled to be ≤3Pa, SiH4 and H2 are introduced at the same time, and the flow ratio SiH4:H2 ≥1:1; the 5-30nm amorphous silicon layer is grown to obtain the a-Si:H film layer.

[0076] Step 4: Complete the a-Si:H film layer of the cell. In the HoFCVD equipment, the hot wire maintains a certain current (≥30A), controls the pressure ≤5Pa, and introduces SiH4 and NH3 at the same time. The flow ratio NH3:SiH4 ≥2:1 is used to complete the growth of the 1-100nm silicon nitride layer to obtain SiN x :H film layer; or

[0077] Control the pressure ≤5Pa, and introduce SiH4, NH3, H2 and O2 at the same time, with the flow ratio of NH3:SiH4≥2:1, the flow ratio of H2:SiH4≥1:1, and the flow ratio of O2:SiH4≥1:1 to complete the growth of 1-100nm silicon nitride oxide layer to obtain SiN x O y :H film layer.

[0078] Step 5: a-Si:H film and SiN x :H film, or a-Si:H film SiN x O y :H film layers together constitute the composite film passivation layer at the cutting edge of the cell.

[0079] Therefore, in order to ensure that the a-Si:H film is not damaged, the SiN x :H film or SiN x O y :H film layer, the temperature of the silicon wafer cannot exceed 250℃. Using HoFCVD to prepare the above composite film layer, SiN can be successfully prepared in the range of room temperature to 200℃. x :H film or SiN x O y :H film. In addition, the film prepared by HoFCVD has a low refractive index: for example, SiN x :H film layer 1.7-2.1 continuously adjustable, SiN x O y :H film layer can be as low as 1.5, the film layer has good density and does not affect the light transmittance.

[0080] In another embodiment of the present invention, the single-layer structure includes an a-Si:H film layer or a SiN x :H film layer.

[0081] When the single-layer structure only includes an a-Si:H film layer, the present invention uses HoFCVD (hot-filament chemical vapor deposition) equipment or technology to prepare the a-Si:H film layer. The specific process steps are as follows:

[0082] Step 1: Stack multiple solar cells and install them in a fixture, with the exposed edges of the cells facing the outside of the fixture mouth and no obvious gaps between the cells. The fixture is placed in the cavity of the HoFCVD equipment, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0083] Step 2: The stacked cells are placed in the HoFCVD equipment, the hot wire maintains a certain current (≥30A), and then a certain amount of H2 (200-1000sccm) is introduced to perform hydrogen etching on the silicon wafer surface.

[0084] Step 3: Control the pressure ≤3Pa, introduce SiH4, continue to control the pressure ≤3Pa, introduce SiH4 and H2 at the same time, with a flow ratio of SiH4:H2 ≥1:1, complete the growth of a 5-30nm amorphous silicon layer, and obtain an a-Si:H passivation film layer.

[0085] When the single-layer structure consists only of SiN x :H film, the present invention uses HoFCVD (hot wire chemical vapor deposition) equipment or technology to perform SiN x :H film preparation. The specific process steps are as follows:

[0086] Step 1: Stack multiple solar cells and install them in a fixture, with the exposed edges of the cells facing the outside of the fixture mouth and no obvious gaps between the cells. The fixture is placed in the cavity of the HoFCVD equipment, with the exposed edges of the silicon wafers at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0087] Step 2: The stacked cells are placed in the HoFCVD equipment, the hot wire maintains a certain current (≥30A), and then a certain amount of H2 (200-1000sccm) is introduced to perform hydrogen etching on the silicon wafer surface.

[0088] Step 3: The hot wire maintains a certain current (≥30A), controls the pressure ≤5Pa, and introduces SiH4 and NH3 at the same time, with a flow ratio of NH3:SiH4≥2:1, to complete the growth of a 1-100nm silicon nitride layer to obtain SiN x :H passivation film layer.

[0089] Preparation of a-Si:H and SiN by traditional tubular PECVD technology x The a-Si:H film requires a high temperature of about 400°C, which will not only damage the a-Si:H film deposited on the surface of the HJT battery, but also cause the film layer to be uneven or defective. Although the plate PECVD technology can avoid the high temperature problem, its equipment is expensive and has a low cost-effectiveness, making it difficult to apply on a large scale. Therefore, the above embodiment of the present invention uses HoFCVD to prepare the above a-Si:H film or SiN x:H film layer, a-Si:H film layer or SiN x The process of the present invention is simple, cost-effective and can be applied on a large scale.

[0090] Example 1

[0091] A method for passivating the cut edge of a solar cell, wherein a hot wire chemical vapor deposition device is used to deposit a passivation composite film layer on the cut edge, wherein the passivation composite film layer includes an a-Si:H film layer and a SiN x :H film layer, comprising the following steps:

[0092] (1) Stack multiple cells and place them in a fixture, with the exposed edges of the cells facing the outside of the fixture opening, and with no obvious gaps between the cells. Place the fixture into the cavity of the HoFCVD device, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0093] (2) The stacked cells are placed in a HoFCVD device, heated by a 30A current through the hot wire, and then etched with hydrogen at a flow rate of 200 sccm.

[0094] (3) The stacked cells were placed in the HoFCVD equipment, and a 30A current was continued to be supplied to the hot wire for heating. The pressure was controlled at 3Pa, and SiH4 was introduced. The pressure was continued to be controlled at 3Pa, and SiH4 and H2 were introduced simultaneously. The flow ratio of SiH4:H2 was 1:1. A 5nm amorphous silicon layer was grown at 25°C to obtain an a-Si:H film layer.

[0095] (4) The cell with a-Si:H film layer is placed in the HoFCVD device, and the hot wire is kept heated by 30A current, the pressure is controlled at 5Pa, and SiH4 and NH3 are introduced at the same time, with a flow ratio of NH3:SiH4=2:1. A 1nm silicon nitride layer is grown at 25℃, and SiN is deposited on the a-Si:H film layer. x :H film layer, thereby forming a passivation composite film layer on the cutting edge.

[0096] Example 2

[0097] A method for passivating the cut edge of a solar cell, wherein a hot wire chemical vapor deposition device is used to deposit a passivation composite film layer on the cut edge, wherein the passivation composite film layer includes an a-Si:H film layer and a SiN x :H film layer, comprising the following steps:

[0098] (1) Stack multiple cells and place them in a fixture, with the exposed edges of the cells facing the outside of the fixture opening, and with no obvious gaps between the cells. Place the fixture into the cavity of the HoFCVD device, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0099] (2) The stacked cells are placed in a HoFCVD device, where a 32A current is passed through the hot wire to heat the cells. A 600sccm flow of H2 is then introduced to hydrogen etch the silicon wafer surface.

[0100] (3) The stacked cells were placed in the HoFCVD equipment, and the heating current of 32A was continued to be supplied to the hot wire for heating. The pressure was controlled at 2Pa, and SiH4 was introduced. The pressure was continued to be controlled at 2Pa, and SiH4 and H2 were introduced at the same time. The flow ratio of SiH4:H2=2:1 was used to complete the growth of a 20nm amorphous silicon layer at 100°C to obtain an a-Si:H film layer.

[0101] (4) The cell with a-Si:H film layer is placed in the HoFCVD device, and the hot wire is kept heated by 32A current, the pressure is controlled at 4Pa, and SiH4 and NH3 are introduced at the same time, with a flow ratio of NH3:SiH4=3:1. A 50nm silicon nitride layer is grown at 100℃, and SiN is deposited on the a-Si:H film layer. x :H film layer, thereby forming a passivation composite film layer on the cutting edge.

[0102] Example 3

[0103] A method for passivating the cut edge of a solar cell, wherein a hot wire chemical vapor deposition device is used to deposit a passivation composite film layer on the cut edge, wherein the passivation composite film layer includes an a-Si:H film layer and a SiN x :H film layer, comprising the following steps:

[0104] (1) Stack multiple cells and place them in a fixture, with the exposed edges of the cells facing the outside of the fixture opening, and with no obvious gaps between the cells. Place the fixture into the cavity of the HoFCVD device, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0105] (2) The stacked cells are placed in a HoFCVD device, where a 36A current is passed through the hot wire to heat the cells. A 1000sccm flow of H2 is then introduced to hydrogen etch the silicon wafer surface.

[0106] (3) The stacked cells were placed in the HoFCVD equipment, and the heating current of 36A was continued to be supplied to the hot wire for heating. The pressure was controlled at 1Pa, and SiH4 was introduced. The pressure was continued to be controlled at 1Pa, and SiH4 and H2 were introduced at the same time. The flow ratio of SiH4:H2=3:1 was used to complete the growth of a 30nm amorphous silicon layer at 200℃ to obtain an a-Si:H film layer.

[0107] (4) The cell with the a-Si:H film layer is placed in the HoFCVD device, and the hot wire is kept heated by a 36A current, the pressure is controlled at 3Pa, and SiH4 and NH3 are introduced at the same time, with a flow ratio of NH3:SiH4=4:1. The 100nm silicon nitride layer is grown at 200℃, and SiN is deposited on the a-Si:H film layer. x :H film layer, thereby forming a passivation composite film layer on the cutting edge.

[0108] Example 4

[0109] A method for passivating the cut edge of a solar cell, wherein a hot wire chemical vapor deposition device is used to deposit a passivation composite film layer on the cut edge, wherein the passivation composite film layer includes an a-Si:H film layer and a SiN x O y :H film layer, comprising the following steps:

[0110] (1) Stack multiple cells and place them in a fixture, with the exposed edges of the cells facing the outside of the fixture opening, and with no obvious gaps between the cells. Place the fixture into the cavity of the HoFCVD device, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0111] (2) The stacked cells are placed in a HoFCVD device, heated by a 30A current through the hot wire, and then etched with hydrogen at a flow rate of 200 sccm.

[0112] (3) The stacked cells were placed in the HoFCVD equipment, and the heating current of 30A was continued to be supplied to the hot wire for heating. The pressure was controlled at 3Pa, and SiH4 was introduced. The pressure was continued to be controlled at 3Pa, and SiH4 and H2 were introduced at the same time. The flow ratio of SiH4:H2 was 1:1. A 5nm amorphous silicon layer was grown at 25°C to obtain an a-Si:H film layer.

[0113] (4) The cell with a-Si:H film layer is placed in the HoFCVD device, and the hot wire is kept heated by 30A current, the pressure is controlled at 5Pa, and SiH4, NH3, H2 and O2 are introduced at the same time, with a flow ratio of NH3:SiH4=2:1, a flow ratio of H2:SiH4=1:1, and a flow ratio of O2:SiH4=1:1. A 1nm silicon nitride oxide layer is grown at 25°C, and SiN is deposited on the a-Si:H film layer. x O y :H film layer, thereby forming a passivation composite film layer on the cutting edge.

[0114] Example 5

[0115] A method for passivating the cut edge of a solar cell, wherein a hot wire chemical vapor deposition device is used to deposit a passivation composite film layer on the cut edge, wherein the passivation composite film layer includes an a-Si:H film layer and a SiN x O y :H film layer, comprising the following steps:

[0116] (1) Stack multiple cells and place them in a fixture, with the exposed edges of the cells facing the outside of the fixture opening, and with no obvious gaps between the cells. Place the fixture into the cavity of the HoFCVD device, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0117] (2) The stacked cells are placed in a HoFCVD device, where a 32A current is passed through the hot wire to heat the cells. A 600sccm flow of H2 is then introduced to hydrogen etch the silicon wafer surface.

[0118] (3) The stacked cells were placed in the HoFCVD equipment, and the heating current of 32A was continued to be supplied to the hot wire for heating. The pressure was controlled at 2Pa, and SiH4 was introduced. The pressure was continued to be controlled at 2Pa, and SiH4 and H2 were introduced at the same time. The flow ratio of SiH4:H2=2:1 was used to complete the growth of a 20nm amorphous silicon layer at 100°C to obtain an a-Si:H film layer.

[0119] (4) The cell with a-Si:H film layer is placed in the HoFCVD device, and the hot wire is kept heated by 32A current, and the pressure is controlled at 4Pa. SiH4, NH3, H2 and O2 are introduced at the same time, with a flow ratio of NH3:SiH4=3:1, a flow ratio of H2:SiH4=2:1, and a flow ratio of O2:SiH4=2:1. A 50nm silicon nitride oxide layer is grown at 100℃, and SiN is deposited on the a-Si:H film layer. x O y :H film layer, thereby forming a passivation composite film layer on the cutting edge.

[0120] Example 6

[0121] A method for passivating the cut edge of a solar cell, wherein a hot wire chemical vapor deposition device is used to deposit a passivation composite film layer on the cut edge, wherein the passivation composite film layer includes an a-Si:H film layer and a SiN x O y :H film layer, comprising the following steps:

[0122] (1) Stack multiple cells and place them in a fixture, with the exposed edges of the cells facing the outside of the fixture opening, and with no obvious gaps between the cells. Place the fixture into the cavity of the HoFCVD device, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0123] (2) The stacked cells are placed in a HoFCVD device, where a 36A current is passed through the hot wire to heat the cells. A 1000sccm flow of H2 is then introduced to hydrogen etch the silicon wafer surface.

[0124] (3) The stacked cells were placed in the HoFCVD equipment, and the heating current of 36A was continued to be supplied to the hot wire for heating. The pressure was controlled at 1Pa, and SiH4 was introduced. The pressure was continued to be controlled at 1Pa, and SiH4 and H2 were introduced at the same time. The flow ratio of SiH4:H2=3:1 was used to complete the growth of a 30nm amorphous silicon layer at 200℃ to obtain an a-Si:H film layer.

[0125] (4) The cell with a-Si:H film layer is placed in the HoFCVD device, and the hot wire is kept heated by 36A current, the pressure is controlled at 3Pa, and SiH4, NH3, H2 and O2 are introduced at the same time, with a flow ratio of NH3:SiH4=4:1, a flow ratio of H2:SiH4=3:1, and a flow ratio of O2:SiH4=3:1. A 100nm silicon nitride oxide layer is grown at 200℃, and SiN is deposited on the a-Si:H film layer. x O y :H film layer, thereby forming a passivation composite film layer on the cutting edge.

[0126] Example 7

[0127] A method for passivating the cut edge of a solar cell wafer, wherein a hot wire chemical vapor deposition device is used to deposit a passivation film layer on the cut edge, wherein the passivation film layer only comprises an a-Si:H film layer, and comprises the following steps:

[0128] (1) Stack multiple cells and place them in a fixture, with the exposed edges of the cells facing the outside of the fixture opening, and with no obvious gaps between the cells. Place the fixture into the cavity of the HoFCVD device, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0129] (2) The stacked cells are placed in a HoFCVD device, heated by a 30A current through the hot wire, and then etched with hydrogen at a flow rate of 200 sccm.

[0130] (3) The stacked cells are placed in the HoFCVD equipment, and a 30A current is continued to be supplied to the hot wire for heating. The pressure is controlled at 3Pa, and SiH4 is introduced. The pressure is continued to be controlled at 3Pa, and SiH4 and H2 are introduced at the same time. The flow ratio SiH4:H2=1:1 is used to complete the growth of a 5nm amorphous silicon layer at 25°C to obtain an a-Si:H passivation film layer.

[0131] Example 8

[0132] A method for passivating the cut edge of a solar cell wafer, wherein a hot wire chemical vapor deposition device is used to deposit a passivation film layer on the cut edge, wherein the passivation film layer only comprises an a-Si:H film layer, and comprises the following steps:

[0133] (1) Stack multiple cells and place them in a fixture, with the exposed edges of the cells facing the outside of the fixture opening, and with no obvious gaps between the cells. Place the fixture into the cavity of the HoFCVD device, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0134] (2) The stacked cells are placed in a HoFCVD device, where a 32A current is passed through the hot wire to heat the cells. A 600sccm flow of H2 is then introduced to hydrogen etch the silicon wafer surface.

[0135] (3) The stacked cells are placed in the HoFCVD equipment, and the hot wire is kept heated at 32A. The pressure is controlled at 2Pa, and SiH4 is introduced. The pressure is continued to be controlled at 2Pa, and SiH4 and H2 are introduced at the same time. The flow ratio SiH4:H2=2:1 is used to complete the growth of a 20nm amorphous silicon layer at 100℃ to obtain an a-Si:H passivation film layer.

[0136] Example 9

[0137] A method for passivating the cut edge of a solar cell wafer, wherein a hot wire chemical vapor deposition device is used to deposit a passivation film layer on the cut edge, wherein the passivation film layer only comprises an a-Si:H film layer, and comprises the following steps:

[0138] (1) Stack multiple cells and place them in a fixture, with the exposed edges of the cells facing the outside of the fixture opening, and with no obvious gaps between the cells. Place the fixture into the cavity of the HoFCVD device, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0139] (2) The stacked cells are placed in a HoFCVD device, where a 36A current is passed through the hot wire to heat the cells. A 1000sccm flow of H2 is then introduced to hydrogen etch the silicon wafer surface.

[0140] (3) The stacked cells are placed in the HoFCVD equipment, and the hot wire is kept heated at 36A. The pressure is controlled at 1Pa, and SiH4 is introduced. The pressure is continued to be controlled at 1Pa, and SiH4 and H2 are introduced at the same time. The flow ratio SiH4:H2=3:1 is used to complete the growth of a 30nm amorphous silicon layer at 200℃ to obtain an a-Si:H passivation film layer.

[0141] Example 10

[0142] A method for passivating the cut edge of a solar cell, wherein a hot wire chemical vapor deposition device is used to deposit a passivation film layer on the cut edge. The passivation film layer only includes SiN x :H film layer, comprising the following steps:

[0143] (1) Stack multiple cells and place them in a fixture, with the exposed edges of the cells facing the outside of the fixture opening, and with no obvious gaps between the cells. Place the fixture into the cavity of the HoFCVD device, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0144] (2) The stacked cells are placed in a HoFCVD device, heated by a 30A current through the hot wire, and then etched with hydrogen at a flow rate of 200 sccm.

[0145] (3) Continue to keep the hot wire heated by 30A current, control the pressure to 5Pa, and introduce SiH4 and NH3 at the same time, with a flow ratio of NH3:SiH4=2:1, and complete the growth of 1nm silicon nitride layer at 25℃ to obtain SiN x :H passivation film layer.

[0146] Example 11

[0147] A method for passivating the cut edge of a solar cell, wherein a hot wire chemical vapor deposition device is used to deposit a passivation film layer on the cut edge. The passivation film layer only includes SiN x :H film layer, comprising the following steps:

[0148] (1) Stack multiple cells and place them in a fixture, with the exposed edges of the cells facing the outside of the fixture opening, and with no obvious gaps between the cells. Place the fixture into the cavity of the HoFCVD device, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0149] (2) The stacked cells are placed in a HoFCVD device, where a 32A current is passed through the hot wire to heat the cells. A 600sccm flow of H2 is then introduced to hydrogen etch the silicon wafer surface.

[0150] (3) Continue to keep the hot wire heated by 32A current, control the pressure to 4Pa, and introduce SiH4 and NH3 at the same time, with a flow ratio of NH3:SiH4=3:1, and complete the growth of a 50nm silicon nitride layer at 100℃ to obtain SiN x :H passivation film layer.

[0151] Example 12

[0152] A method for passivating the cut edge of a solar cell, wherein a hot wire chemical vapor deposition device is used to deposit a passivation film layer on the cut edge. The passivation film layer only includes SiNx :H film layer, comprising the following steps:

[0153] (1) Stack multiple cells and place them in a fixture, with the exposed edges of the cells facing the outside of the fixture opening, and with no obvious gaps between the cells. Place the fixture into the cavity of the HoFCVD device, with the exposed edges of the cells at a certain distance from the hot wire, and the edges of the stacked cells facing the hot wire.

[0154] (2) The stacked cells are placed in a HoFCVD device, where a 36A current is passed through the hot wire to heat the cells. A 1000sccm flow of H2 is then introduced to hydrogen etch the silicon wafer surface.

[0155] (3) Continue to keep the hot wire heated by 36A current, control the pressure to 3Pa, and introduce SiH4 and NH3 at the same time, with a flow ratio of NH3:SiH4=4:1, and complete the growth of 100nm silicon nitride layer at 200℃ to obtain SiN x :H film layer.

[0156] It can be seen from the above examples 1-12 that the present invention can use HoFCVD equipment or technology to prepare passivation films on the cut edges of solar cells, and can successfully prepare a-Si:H films, SiN films, and other passivation films in the range of room temperature to 200°C. x :H film or SiN x O y :H film layer, avoiding damage to the intrinsic a-Si:H film layer, retaining the intrinsic a-Si:H film layer's low defect state density, low carrier recombination, and excellent passivation performance advantages, and solving the problem of high-temperature coating damaging the a-Si:H film deposited on the surface of the HJT cell and causing uneven film layers or defects. The solar cell passivation a-Si:H+SiN x :H or a-Si:H+SiN x O y The :H composite film combines the low defect state density, low carrier recombination, and excellent passivation performance of a-Si:H films with the good thermal and chemical stability of SiNx:H or SiNxOy:H films, achieving low defect state density, high passivation performance, and excellent weather resistance for solar cell passivation films. The films prepared by the HoFCVD method in this invention have a low refractive index: for example, the refractive index of SiNx:H films can be continuously adjusted from 1.7 to 2.1, and that of SiNxOy:H films can be as low as 1.5. The films are highly compact and do not affect light transmittance.

[0157] It can be seen that the present invention provides a film layer with excellent comprehensive performance of low defect state density, high passivation performance, excellent weather resistance, and high optical transmittance, and a coating technology with simple process, high cost performance, and scalable application.

[0158] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to the process, method, article or device. In the absence of further limitations, an element defined by the sentence "including a..." does not exclude the presence of additional identical elements in the process, method, article or device that includes the element.

[0159] The foregoing description is intended to be merely an embodiment of the present invention, which is intended to enable those skilled in the art to understand and implement the present invention. Various modifications to the described embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Claims

1. A method for passivating the cut edges of solar cells, characterized in that: Using hot wire chemical vapor deposition equipment to deposit a passivation film layer on the cutting edge includes the following steps: Expose the cut edge of the cell and align it with the hot wire; Pass an electric current through the hot wire to heat it, and then pass H2 into it to perform hydrogen etching on the surface of the silicon wafer; Keep the hot wire heated by current, introduce SiH4 at a first pressure, then maintain the first pressure while introducing SiH4 and H2 simultaneously, and complete the growth of the amorphous silicon layer at room temperature to 200°C to obtain an a-Si:H film layer; Continue to keep the hot wire heated by current, and at the second pressure, introduce SiH4 and NH3 at the same time to complete the growth of silicon nitride layer at room temperature to 200℃, and deposit SiN on the a-Si:H film layer. x :H film layer, thereby forming a passivation composite film layer of the cutting edge, or under the second pressure, SiH4, NH3, H2 and O2 are introduced at the same time, and the silicon nitride oxide layer is grown at room temperature to 200 ° C, and SiN is deposited on the a-Si:H film layer. x O y :H film layer, thereby forming a passivation composite film layer on the cutting edge, in: The current of the hot wire is ≥30A, and the flow rate of H2 is 200-1000sccm; The first pressure is ≤3Pa, the flow ratio of SiH4 and H2 introduced is SiH4:H2≥1:1, and the thickness of the amorphous silicon layer is 5-30nm; When SiN is deposited on a-Si:H film x : H film layer, the second pressure ≤ 5Pa, the flow ratio of SiH4 and NH3 into NH3:SiH4 ≥ 2:1, the thickness of the silicon nitride layer is 1-100nm; When SiN is deposited on a-Si:H film x O y : H film layer, the second pressure ≤ 5Pa, the flow ratio of SiH4, NH3, H2 and O2 into NH3:SiH4 ≥ 2:1, the flow ratio of H2:SiH4 ≥ 1:1, the flow ratio of O2:SiH4 ≥ 1:1, the thickness of the silicon oxynitride layer is 1-100nm; When depositing SiN x :H film layer, the obtained SiN x :The refractive index of the H film is 1.7-2.1 and is continuously adjustable; when depositing SiN x O y :H film layer, the obtained SiN x O y : The refractive index of the H film layer is ≤1.

5.

2. A method for passivating the cut edges of solar cells, characterized in that: A hot wire chemical vapor deposition device is used to deposit a passivation film layer on the cutting edge, wherein the passivation film layer only includes an amorphous silicon layer. The method includes the following steps: Expose the cut edge of the cell and align it with the hot wire; Pass an electric current through the hot wire to heat it, and pass H2 into it to perform hydrogen etching on the surface of the silicon wafer; Keep the hot wire heated by current, introduce SiH4 at the first pressure, then maintain the first pressure and introduce SiH4 and H2 at the same time, complete the growth of the amorphous silicon layer at room temperature to 200 ° C, and obtain the a-Si:H passivation film layer. in: The current of the hot wire is ≥30A, and the flow rate of H2 is 200-1000sccm; The first pressure is ≤3Pa, the flow ratio of SiH4 and H2 introduced is SiH4:H2≥1:1, and the thickness of the amorphous silicon layer is 5-30nm.

3. A method for passivating the cut edges of solar cells, characterized in that: A hot wire chemical vapor deposition device is used to deposit a passivation film layer on the cutting edge, wherein the passivation film layer only includes a silicon nitride layer. The method includes the following steps: Expose the cut edge of the cell and align it with the hot wire; Pass an electric current through the hot wire to heat it, and pass H2 into it to perform hydrogen etching on the surface of the silicon wafer; Keep the hot wire heated by current, and at the second pressure, introduce SiH4 and NH3 at the same time to complete the growth of silicon nitride layer at room temperature to 200℃ to obtain SiN x : H passivation film layer, in: The current of the hot wire is ≥30A, and the flow rate of H2 is 200-1000sccm; The second pressure is ≤5Pa, the flow ratio of SiH4 and NH3 into the silicon nitride layer is NH3:SiH4≥2:1, and the thickness of the silicon nitride layer is 1-100nm.

4. A solar cell cut edge passivation film layer prepared by the method for passivating the cut edge of a solar cell according to claim 1, characterized in that: include: a-Si:H film layer; SiN deposited on a-Si:H film x : H film or SiN x O y : H film layer.

5. A solar cell cut edge passivation film layer prepared by the method for passivating the cut edge of a solar cell according to claim 2 or 3, characterized in that: Including a-Si:H passivation film or SiN x : H passivation film layer.

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