Solar cells and photovoltaic modules

Abstract

This utility model discloses a solar cell and a photovoltaic module. The solar cell includes: a cell body, including a first surface, a second surface, and a side section connecting the first surface and the second surface; a passivation layer, at least covering the side section; and a protective layer, at least covering a portion of the surface of the passivation layer. The solar cell and photovoltaic module of this utility model have excellent long-term passivation performance and a long lifespan for the solar cell.

Description

Technical Field

[0001] This utility model belongs to the field of solar cell manufacturing technology, specifically relating to a solar cell and a photovoltaic module. Background Technology

[0002] In the production of solar cells, the edge areas of laser-cut solar cells contain a large number of dangling bonds and defect states, which require passivation treatment to reduce carrier recombination and improve cell efficiency.

[0003] In existing technologies, chemical vapor deposition (CVD) is typically used to form passivation layers on the edge regions of solar cells, or atomic layer deposition (ALD) is used to form aluminum oxide passivation layers on the edge regions of solar cells. While the formation of these passivation layers has some effect on reducing carrier recombination and improving cell efficiency, it also has certain drawbacks. After the passivation layer absorbs moisture, it is prone to increasing interface defects, thus reducing long-term passivation performance.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this utility model and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a solar cell and a photovoltaic module that can improve the long-term passivation performance of the edge region of the solar cell and increase the lifespan of the solar cell.

[0006] To achieve the above objectives, the technical solution provided by a specific embodiment of this utility model is as follows:

[0007] A solar cell, comprising:

[0008] The battery cell body includes a first surface, a second surface, and a side section connecting the first surface and the second surface, which are disposed opposite to each other.

[0009] A passivation layer, at least covering the side cut surface;

[0010] A protective layer that at least covers a portion of the surface of the passivation layer.

[0011] In one or more embodiments of the present invention, the passivation layer extends from the side section and covers a portion of the first surface and / or a portion of the second surface of the battery cell body.

[0012] In one or more embodiments of the present invention, the passivation layer extends for a length of 1 mm to 5 mm on the first surface and / or the second surface.

[0013] In one or more embodiments of the present invention, a first solder joint is provided on the first surface adjacent to the side section;

[0014] The length of the passivation layer extending on the first surface is less than or equal to the distance between the side section and the first solder joint, and / or the extension area of ​​the passivation layer on the first surface includes a colored area distributed close to the side section, the width of which is less than or equal to half the distance between the side section and the first solder joint.

[0015] In one or more embodiments of the present invention, a second solder joint is provided on the second surface adjacent to the side section;

[0016] The length of the passivation layer extending on the second surface is less than or equal to the distance between the side section and the second solder joint, and / or, the extension region of the passivation layer on the second surface includes a colored region distributed close to the side section, the width of which is less than or equal to half the distance between the side section and the second solder joint.

[0017] In one or more embodiments of the present invention, the protective layer extends from the side section to cover a portion of the first surface and / or a portion of the second surface of the battery cell body.

[0018] In one or more embodiments of the present invention, the protective layer extends for a length of 2 mm to 8 mm on the first surface and / or the second surface.

[0019] In one or more embodiments of the present invention, a first solder joint is provided on the first surface adjacent to the side section, and the extension length of the protective layer on the first surface is less than or equal to the distance between the side section and the first solder joint; and / or,

[0020] A second solder joint is provided on the second surface adjacent to the side section, and the extension length of the protective layer on the second surface is less than or equal to the distance between the side section and the second solder joint.

[0021] In one or more embodiments of the present invention, the protective layer at least covers the passivation layer on the side section; and / or,

[0022] The passivation layer has a thickness of 20 nm to 60 nm; and / or,

[0023] The passivation layer located on the said side section has a uniform thickness; and / or,

[0024] The thickness of the protective layer is 1μm~5μm; and / or,

[0025] The protective layer located on the side section has a uniform thickness.

[0026] In one or more embodiments of the present invention, the protective layer comprises an organosilicon compound; and / or,

[0027] The protective layer contains a silane coupling agent, including γ-aminopropyltriethoxysilane, hexadecyltrimethoxysilane, and trifluoropropylsilane; and / or,

[0028] The protective layer contains a hydrophobic agent, including methyltrimethoxysilane, isobutyltriethoxysilane, tridecafluorooctyl methacrylate; and / or,

[0029] The passivation layer includes aluminum oxide, silicon oxide, aluminum nitride, and polycrystalline silicon.

[0030] A photovoltaic module includes the aforementioned solar cell.

[0031] Compared with the prior art, this utility model provides double passivation protection to the side cut surface of the solar cell by setting a passivation layer and a protective layer on the side cut surface, which solves the problem of passivation performance degradation caused by moisture absorption of the passivation layer and improves the life of the solar cell. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of a solar cell in one embodiment of the present invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0035] To reduce internal power loss in solar cell modules, the modules can be manufactured by cutting the entire solar cell in half or thirds. This reduces module current and internal resistance, thereby lowering internal power loss and increasing module output power and electricity generation. Currently, the primary method for dicing solar cells is laser cutting.

[0036] As mentioned in the background section, after a solar cell is laser-cut, the silicon surface at the edge of the cell body is directly exposed to the air, which introduces a large number of dangling bonds and defect states, which become effective recombination centers for charge carriers and reduce the performance of the cell.

[0037] To address the aforementioned technical problems, this utility model provides a solar cell and a photovoltaic module. By providing a passivation layer and a protective layer on at least the side section of the cell body, the side section is subjected to double passivation protection. This allows the protective layer to tightly cover the passivation layer, forming a protective barrier. This not only enhances the passivation effect but also effectively prevents moisture penetration, solving the problem of passivation performance degradation caused by moisture absorption of the passivation layer and further improving the lifespan of the solar cell.

[0038] like Figure 1 As shown, the solar cell of this invention includes a cell body 10, a passivation layer 20, and a protective layer 30. The cell body 10 includes a first surface S1 (i.e., the front or light-receiving surface), a second surface S2 (i.e., the back or backlighting surface), and at least one side section S3 connecting the first surface S1 and the second surface S2. The passivation layer 20 covers at least the side section S3 for passivation protection. The protective layer 30 covers at least a portion of the surface of the passivation layer 20. The protective layer 30 contains an organosilicon compound. The groups of the organosilicon compound cross-link with the hydroxyl groups in the bare silicon of the side section S3. Simultaneously, the groups of the organosilicon compound can also cross-link with the hydroxyl groups in the passivation layer 20 on the side section S3, forming Si-OM covalent bonds, where M is a metal or silicon, to supplement the passivation of the side section S3 and further improve the passivation effect.

[0039] Understandably, the entire solar cell can be sliced ​​using laser cutting—for example, with a laser cutting machine—to obtain a cell body 10 with a side cut surface S3. The cutting precision of the laser cutting is preferably controlled within ±5μm to ensure that there are no cracks on the side cut surface of the cell body 10. After cutting, the cell body 10 can be cleaned to remove debris residue from its surface, especially from the side cut surface S3.

[0040] Using deposition equipment such as ALD (Atomic Layer Deposition) or CVD (Chemical Vapor Deposition), a uniform and dense passivation layer 20 with a certain thickness is deposited on the edge side section S3 of the cell body 10, with aluminum source and / or other source gases that can form passivation layer 20 as precursors.

[0041] The passivation layer 20 may include one or more thin films of aluminum oxide, silicon oxide, aluminum nitride, and polycrystalline silicon. The thickness of the passivation layer 20 is 20 nm to 60 nm.

[0042] In a preferred embodiment, the passivation layer 20 is only disposed on the side section S3 of the battery cell body 10.

[0043] However, due to process limitations, while a passivation layer 20 is deposited on the side section S3 of the cell body 10, the passivation layer 20 also extends from the side section S3 and is deposited around the edge area of ​​a portion of the first surface S1 and / or a portion of the second surface S2 of the cell body 10 adjacent to the side section S3, forming a passivation layer around the edge.

[0044] Therefore, in another embodiment, the passivation layer 20 is not only disposed on the side section S3 of the battery cell body 10, but also extends to cover the edge region of the first surface S1 and / or the edge region of the second surface S2. The extension length W11 of the passivation layer 20 covering the edge region of the first surface S1 is approximately 1 mm to 5 mm. The extension length W12 of the passivation layer 20 covering the edge region of the second surface S2 is approximately 1 mm to 5 mm. That is, the width of the passivation layer around the first surface S1 and / or the second surface S2 ranges from 1 mm to 5 mm.

[0045] It is understandable that solder joints (H11-H1n, H21-H2n) for welding with solder ribbons are usually provided on the first surface S1 and / or the second surface S2 of the cell body 10. If the passivation layer around the edge region of the first surface S1 and / or the second surface S2 of the cell body 10 covers the solder joints on the first surface S1 and / or the second surface S2 of the cell body 10, it will affect the electrical connection of subsequent welding.

[0046] In another embodiment, to avoid affecting the electrical connection performance of the solar cells during later series-parallel connection, the solder joint H11, which is closest to the side section S3 among the solder joints H11-H1n on the first surface S1, is defined as the first solder joint; and the solder joint H21, which is closest to the side section S3 among the solder joints H21-H2n on the second surface S2, is defined as the second solder joint. The extension length W11 of the passivation layer 20 on the first surface S1 of the cell body 10 is defined to be less than or equal to the distance between the side section S3 of the cell body 10 and the first solder joint H11 at the edge of the first surface of the cell body 10. The extension length W12 of the passivation layer 20 on the second surface S2 of the cell body 10 is defined to be less than or equal to the distance between the side section S3 of the cell body 10 and the second solder joint H21 at the edge of the second surface of the cell body 10.

[0047] It is understandable that, since the first solder joint and / or the second solder joint are generally about 6mm away from the edge of the side section S3 of the cell body 10, the width of the passivation layer wrapped around the plane (first surface and / or first surface) can be directly limited to 1mm to 5mm.

[0048] In the above embodiments, the passivation layer 20 located on the side section S3 of the battery cell body 10 has a uniform thickness, ranging from about 20nm to 60nm; the thickness of the passivation layer 20 located on the first surface and / or the second surface of the battery cell body 10 is variable and non-uniform, and preferably, the thickness of the passivation layer 20 located on the first surface and / or the second surface of the battery cell body 10 gradually decreases along the side section S3 to the center of the battery cell body.

[0049] From a macroscopic perspective, in actual production, the approximate coverage area of ​​the passivation layer 20 can be determined by observing its color change. Because after passivation layer plating, the passivation layer is thicker closer to the edge of the side cut surface S3 on the first and / or second surfaces, and the thicker areas will exhibit a special color; for example, the aluminum oxide passivation layer will appear yellow. That is, the extended coverage area of ​​the passivation layer 20 on the first surface S1 and / or the second surface S2 includes the colored areas distributed near the side cut surface S3. Therefore, based on the limitation of the width range of the colored areas at the edges of the first and / or second surfaces, the approximate extension length W11 / W12 of the passivation layer 20 on the first and / or second surfaces can be determined.

[0050] In another embodiment, in order to ensure that the extension length W11 of the passivation layer 20 around the first surface S1 does not exceed the distance from the first solder point H11 at the edge of the first surface to the side section S3, and the extension length W12 of the passivation layer 20 around the second surface does not exceed the distance from the second solder point H21 at the edge of the second surface to the side section S3, the width C11 of the colored area of ​​the passivation layer 20 on the first surface S1 can be limited to not exceeding half the distance between the side section S3 of the battery cell body 10 and the first solder point H11 at the edge of the first surface of the battery cell body 10, and the width C12 of the colored area of ​​the passivation layer 20 on the second surface S2 can be limited to not exceeding half the distance between the side section S3 of the battery cell body 10 and the second solder point H21 at the edge of the second surface of the battery cell body 10.

[0051] It is understood that a protective solution is uniformly sprayed onto the passivation layer 20 of the side section S3 of the cell body using a spraying equipment, so that the protective solution cross-links and bonds with the bare silicon on the side section S3 of the cell body 10, and forms a protective layer 30 covering at least part of the surface of the passivation layer 20 after drying.

[0052] The protective layer 30 contains an organosilicon compound. The thickness of the protective layer is 1 μm to 5 μm.

[0053] In a preferred embodiment, the protective layer 30 contains a silane coupling agent. The silane coupling agent contains active silanol groups (-Si-OH), which can undergo a condensation reaction with the hydroxyl groups (-Si-OH) on the bare silicon surface of the side section S3 of the battery cell body 10 to form stable Si-O-Si covalent bonds. The mass fraction of the silane coupling agent in the protective layer 30 is 1% to 5%. The protective layer 30 may also contain the solvent ethanol or isopropanol.

[0054] In one specific embodiment, the silane coupling agent includes γ-aminopropyltriethoxysilane, hexadecyltrimethoxysilane, trifluoropropylsilane, etc.

[0055] In the above technical solution, the groups of the organosilicon compound in the protective layer 30 cross-link with the hydroxyl groups in the bare silicon of the side section S3 of the battery cell body 10, forming Si-OM covalent bonds. Here, M is a metal or silicon. Specifically, when the protective layer 30 contains a silane coupling agent with active silanol groups (-Si-OH), the active silanol groups (-Si-OH) can undergo a condensation reaction with the hydroxyl groups (-Si-OH) in the bare silicon of the side section S3 of the battery cell body 10, forming stable Si-O-Si covalent bonds. The cross-linking bonding between the protective layer 30 and the battery cell body can supplement the passivation of the side section of the battery cell body, further improving the passivation effect.

[0056] In a preferred embodiment, the protective layer 30 further comprises a water-repellent agent. The mass fraction of the water-repellent agent in the protective layer 30 is 0.5% to 3%.

[0057] In one specific embodiment, the hydrophobic agent includes methyltrimethoxysilane, isobutyltriethoxysilane, tridecafluorooctyl methacrylate, etc.

[0058] In the above technical solution, the hydrophobic agent in the protective layer 30 enables the protective layer 30 formed on the surface of the passivation layer 20 to have a hydrophobic effect, thereby forming a hydrophobic barrier (contact angle > 90°) on the surface of the passivation layer 20, which can effectively prevent water vapor penetration and solve the problem of passivation performance degradation caused by moisture absorption of the passivation layer 20.

[0059] The combination of organosilicon compounds and hydrophobic agents in the protective layer 30 allows the protective layer 30 to tightly cover the passivation layer 20, supplementing passivation and enhancing the passivation effect. At the same time, it forms a hydrophobic barrier to prevent water vapor penetration, further improving passivation performance and extending the lifespan of the solar cell.

[0060] In a preferred embodiment, the protective layer 30 is only disposed on the side section S3 of the cell body 10, that is, the protective layer 30 only needs to cover the passivation layer 20 on the side section S3 of the solar cell 10.

[0061] However, due to the same process limitations, while a protective layer 30 is deposited on the side section S3 of the cell body 10, the protective layer 30 also extends from the side section S3 and is deposited around the edge area of ​​a portion of the first surface S1 and / or a portion of the second surface S2 of the cell body 10 adjacent to the side section S3, forming a protective layer around the edge.

[0062] Therefore, in another embodiment, the protective layer 30 is not only disposed on the passivation layer 20 of the side section S3 of the battery cell body 10, but also extends to cover part or all of the passivation layer 20 covering the edge region of the first surface S1 and / or the edge region of the second surface S2. The extension length W21 of the protective layer 30 covering the edge region of the first surface S1 is approximately 2mm to 8mm. The extension length W22 of the protective layer 30 covering the edge region of the second surface S2 is approximately 2mm to 8mm. That is, the width of the area around the protective layer deposited on the first surface S1 and / or the second surface S2 ranges from 2mm to 8mm.

[0063] Similarly, to ensure that the protective layer 30 does not affect the electrical connection performance during subsequent series-parallel connection of the solar cells, in a preferred embodiment, the extension length W21 of the protective layer 30 on the first surface S1 of the cell body 10 is limited to be less than or equal to the distance between the side section S3 of the cell body 10 and the first solder point H11 at the edge of the first surface of the cell body 10. The extension length W22 of the protective layer 30 on the second surface S2 of the cell body 10 is limited to be less than or equal to the distance between the side section S3 of the cell body 10 and the second solder point H21 at the edge of the second surface of the cell body 10.

[0064] However, experiments have shown that if the extension length W21 / W22 of the protective layer 30 on the first surface S1 and / or the second surface S2 of the cell body 10 is greater than the distance between the side section S3 of the cell body 10 and the first solder point H11 at the edge of the first surface and / or the second solder point H21 at the edge of the second surface, the impact on the electrical connection of subsequent solder joints is not significant. Therefore, the extension range of the protective layer can be slightly expanded, limiting the width of the protective layer wrapped around the plane (first surface and / or second surface) to between 2mm and 8mm.

[0065] In the above embodiments, the protective layer 30 located on the side section S3 of the battery cell body 10 has a uniform thickness, ranging from about 1 μm to 5 μm; the thickness of the protective layer 30 located on the first surface and / or the second surface of the battery cell body 10 is variable and non-uniform, and preferably, the thickness of the protective layer 30 located on the first surface and / or the second surface of the battery cell body 10 gradually decreases along the side section S3 towards the center of the battery cell body.

[0066] In one embodiment, the protective layer 30 may cover the entire surface of the passivation layer 20. In other embodiments, the protective layer 30 may only completely cover the surface of the passivation layer 20 located on the side section S3 of the cell body 10, or the protective layer 30 may completely cover the surface of the passivation layer 20 located on the side section S3 of the cell body 10 and then partially extend to cover the first surface and / or the second surface of the cell body 10.

[0067] This invention also provides a photovoltaic module having the aforementioned solar cells.

[0068] The solar cell and photovoltaic module of this invention provide double passivation protection for the side section by setting a passivation layer and a protective layer on at least the side section of the cell body. This allows the protective layer to tightly cover the passivation layer, forming a protective barrier. While enhancing the passivation effect, it can also effectively prevent moisture penetration, solve the problem of passivation performance degradation caused by moisture absorption of the passivation layer, and further improve the lifespan of the solar cell.

[0069] The passivation effect of the solar cell of this invention will be explained in detail below through several specific embodiments and comparative examples.

[0070] Example 1: (The alumina passivation layer and protective layer include the silane coupling agent - γ-aminopropyltriethoxysilane and the hydrophobic agent - methyltrimethoxysilane)

[0071] Laser halving: A 182.75mm × 182.75mm monocrystalline silicon solar cell is halved using a laser to obtain two 91.375mm × 182.75mm monocrystalline silicon solar cells. The edge roughness Ra of the monocrystalline silicon solar cell is less than 1μm.

[0072] ALD deposition of alumina layer: The monocrystalline silicon solar cell is placed in the ALD device, with TMA (trimethylaluminum) as the aluminum source, a flow rate of 1000 sccm, and a pulse time of 5s; deionized water is used as the oxygen source, with a flow rate of 1500 sccm and a pulse time of 5s. 200 cycles are deposited at 200℃ to form a 20nm thick alumina passivation layer.

[0073] Protective coating solution: Prepare an ethanol solution containing 3% silane coupling agent - γ-aminopropyltriethoxysilane and 2% hydrophobic agent - methyltrimethoxysilane, and spray it onto the edge side cut surface of the monocrystalline silicon solar cell through a precision nozzle at a pressure of 0.3MPa and a speed of 80mm / s to form a 3μm thick protective layer.

[0074] High-temperature dehydration: The side cut surface of the monocrystalline silicon solar cell with protective solution is baked in a 100℃ oven for 20-30 seconds via a conveyor belt to remove residual moisture. The contact angle on the edge cut surface of the monocrystalline silicon solar cell is detected to be 95°, indicating that a hydrophobic protective layer has been formed.

[0075] Testing and packaging: EL test results show no defects and meet standards. After IV test (Current-Voltage Test), the samples are sorted and packaged.

[0076] Example 2: (Silicon oxide passivation layer and protective layer include silane coupling agent - γ-aminopropyltriethoxysilane and hydrophobic agent - methyltrimethoxysilane)

[0077] Laser halving: A 182.75mm × 182.75mm monocrystalline silicon solar cell is halved using a laser to obtain two 91.375mm × 182.75mm monocrystalline silicon solar cells. The edge roughness Ra of the monocrystalline silicon solar cell is less than 1μm.

[0078] ALD deposition of silicon oxide layer: The monocrystalline silicon solar cell is placed in an ALD device, using bis(tert-butoxy)silane (BTBAS, SiH2(OtBu)2) or silicon tetrachloride (SiCl4) as the silicon source, with a flow rate of 1500 sccm and a pulse time of 5 s. Deionized water is used as the oxygen source, with a flow rate of 1500 sccm and a pulse time of 5 s. 200 cycles are deposited at 200℃ to form a 20 nm thick silicon oxide passivation layer.

[0079] Protective coating solution: Prepare an ethanol solution containing 3% silane coupling agent - γ-aminopropyltriethoxysilane and 2% hydrophobic agent - methyltrimethoxysilane, and spray it onto the edge side cut surface of the monocrystalline silicon solar cell through a precision nozzle at a pressure of 0.3MPa and a speed of 80mm / s to form a 3μm thick protective layer.

[0080] High-temperature dehydration: The side cut surface of the monocrystalline silicon solar cell with protective solution is baked in a 100℃ oven for 20-30 seconds via a conveyor belt to remove residual moisture. The contact angle on the edge cut surface of the monocrystalline silicon solar cell is detected to be 95°, indicating that a hydrophobic protective layer has been formed.

[0081] Testing and packaging: EL test results show no defects and meet standards. After IV test (Current-Voltage Test), the samples are sorted and packaged.

[0082] Example 3: (The aluminum nitride passivation layer and protective layer include the silane coupling agent - γ-aminopropyltriethoxysilane and the hydrophobic agent - methyltrimethoxysilane)

[0083] Laser halving: A 182.75mm × 182.75mm monocrystalline silicon solar cell is halved using a laser to obtain two 91.375mm × 182.75mm monocrystalline silicon solar cells. The edge roughness Ra of the monocrystalline silicon solar cell is less than 1μm.

[0084] ALD deposition of aluminum nitride layer: The monocrystalline silicon solar cell is placed in the ALD device, with TMA (trimethylaluminum) as the aluminum source, a flow rate of 1000 sccm, and a pulse time of 5s; ammonia (NH3) or plasma nitrogen (N2 / H2 plasma) as the nitrogen source, a flow rate of 1000 sccm, and a pulse time of 5s. 200 cycles are deposited at 200℃ to form a 20nm thick aluminum nitride passivation layer.

[0085] Protective coating solution: Prepare an ethanol solution containing 3% silane coupling agent - γ-aminopropyltriethoxysilane and 2% hydrophobic agent - methyltrimethoxysilane, and spray it onto the edge side cut surface of the monocrystalline silicon solar cell through a precision nozzle at a pressure of 0.3MPa and a speed of 80mm / s to form a 3μm thick protective layer.

[0086] High-temperature dehydration: The side cut surface of the monocrystalline silicon solar cell with protective solution is baked in a 100℃ oven for 20-30 seconds via a conveyor belt to remove residual moisture. The contact angle on the edge cut surface of the monocrystalline silicon solar cell is detected to be 95°, indicating that a hydrophobic protective layer has been formed.

[0087] Testing and packaging: EL test results show no defects and meet standards. After IV test (Current-Voltage Test), the samples are sorted and packaged.

[0088] Example 4: (The alumina passivation layer and protective layer consist of an ethanol solution of silane coupling agent - hexadecyltrimethoxysilane and hydrophobic agent - isobutyltriethoxysilane)

[0089] Laser halving: The 182.75mm×210mm monocrystalline silicon solar cell is cut into two 105mm×182.75mm monocrystalline silicon solar cells.

[0090] ALD deposition of alumina layer: The monocrystalline silicon solar cell is placed in the ALD device, with TMA (trimethylaluminum) as the aluminum source, a flow rate of 1000 sccm, and a pulse time of 5s; deionized water is used as the oxygen source, with a flow rate of 1500 sccm and a pulse time of 5s. The deposition is carried out at 180℃ for 500 cycles to form a 50nm thick alumina passivation layer.

[0091] Protective coating solution: Prepare an ethanol solution containing 3% silane coupling agent - hexadecyltrimethoxysilane and 2% hydrophobic agent - isobutyltriethoxysilane, and spray it onto the edge side cut surface of the monocrystalline silicon solar cell through a precision nozzle at a pressure of 0.4MPa and a speed of 60mm / s to form a 4μm thick protective layer.

[0092] High-temperature dehydration: The side cut surfaces of the monocrystalline silicon solar cells with protective solution are baked in a 150°C oven for 20-30 seconds via a conveyor belt to remove residual moisture.

[0093] Testing and packaging: EL testing shows no defects in the image, meeting the standards. After IV testing, the samples are graded and packaged.

[0094] Example 5: (The alumina passivation layer and protective layer consist of an ethanol solution of silane coupling agent - trifluoropropylsilane and hydrophobic agent - tridecafluorooctyl methacrylate)

[0095] Laser halving: The 182.75mm×210mm monocrystalline silicon solar cell is cut into two 105mm×182.75mm monocrystalline silicon solar cells.

[0096] ALD deposition of alumina layer: The monocrystalline silicon solar cell is placed in the ALD device, with TMA (trimethylaluminum) as the aluminum source, a flow rate of 1000 sccm, and a pulse time of 5s; deionized water is used as the oxygen source, with a flow rate of 1500 sccm and a pulse time of 5s. 500 cycles are deposited at 180℃ to form a 50nm thick alumina layer.

[0097] Protective coating solution: Prepare an ethanol solution containing 3% silane coupling agent - trifluoropropylsilane and 2% hydrophobic agent - tridecafluorooctyl methacrylate, and spray it onto the edge side cut surface of the monocrystalline silicon solar cell through a precision nozzle at a pressure of 0.4MPa and a speed of 60mm / s to form a 4μm thick protective layer.

[0098] High-temperature dehydration: The side cut surfaces of the monocrystalline silicon solar cells with protective solution are baked in a 150°C oven for 20-30 seconds via a conveyor belt to remove residual moisture.

[0099] Testing and packaging: EL testing shows no defects in the image, meeting the standards. After IV testing, the samples are graded and packaged.

[0100] Comparative Example 1: (Passivation layer only, no protective layer)

[0101] Laser halving: A 182.75mm × 182.75mm monocrystalline silicon solar cell is halved using a laser to obtain two 91.375mm × 182.75mm monocrystalline silicon solar cells. The edge roughness Ra of the monocrystalline silicon solar cell is less than 1μm.

[0102] ALD deposition of alumina layer: The monocrystalline silicon solar cell is placed in the ALD device, with TMA (trimethylaluminum) as the aluminum source, a flow rate of 1000 sccm, and a pulse time of 5s; deionized water is used as the oxygen source, with a flow rate of 1500 sccm and a pulse time of 5s. 200 cycles are deposited at 200℃ to form a 20nm thick alumina passivation layer.

[0103] Testing and packaging: EL test results show no defects and meet standards. After IV test (Current-Voltage Test), the samples are sorted and packaged.

[0104] Comparative Example 2: (No passivation layer, only protective layer)

[0105] Laser halving: A 182.75mm × 182.75mm monocrystalline silicon solar cell is halved using a laser to obtain two 91.375mm × 182.75mm monocrystalline silicon solar cells. The edge roughness Ra of the monocrystalline silicon solar cell is less than 1μm.

[0106] Protective coating solution: Prepare an ethanol solution containing 3% silane coupling agent - γ-aminopropyltriethoxysilane and 2% hydrophobic agent - methyltrimethoxysilane, and spray it onto the edge side cut surface of the monocrystalline silicon solar cell through a precision nozzle at a pressure of 0.3MPa and a speed of 80mm / s to form a 3μm thick protective layer.

[0107] High-temperature dehydration: The side cut surface of the monocrystalline silicon solar cell with protective solution is baked in a 100℃ oven for 20-30 seconds via a conveyor belt to remove residual moisture. The contact angle on the edge cut surface of the monocrystalline silicon solar cell is measured to be 95°, forming a hydrophobic protective layer.

[0108] Testing and packaging: EL test results show no defects and meet standards. After IV test (Current-Voltage Test), the samples are sorted and packaged.

[0109] The solar cells obtained in Examples 1-5 and Comparative Examples 1-2 were subjected to a damp heat test at 85°C / 85%RH for 1000 hours. The specific test results are shown in Table 1.

[0110] Table 1: Statistical table of RH minority carrier test results for different examples:

[0111]

[0112] As shown in Table 1, the solar cell of this invention, through the synergistic protection of the protective layer and the passivation layer, after 1000 hours of 85℃ / 85%RH damp heat test, exhibits a minority carrier reduction of <45% and a minority carrier lifetime retention of >50% at the edge side section. This is significantly better than the single passivation layer of Comparative Example 1 (minority carrier reduction of 60% and retention of 40%) and the single protective layer of Comparative Example 2 (minority carrier reduction of 65% and retention of 35%). Furthermore, the solar cell efficiency is higher, greater than or equal to 25.50%.

[0113] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0114] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A solar cell, characterized by, include: The battery cell body includes a first surface, a second surface, and a side section connecting the first surface and the second surface, which are disposed opposite to each other. A passivation layer, at least covering the side cut surface; A protective layer that at least covers a portion of the surface of the passivation layer.

2. The solar cell according to claim 1, wherein The passivation layer extends from the side section and covers a portion of the first surface and / or a portion of the second surface of the battery cell body.

3. The solar cell according to claim 2, wherein, The passivation layer extends for 1 mm to 5 mm on the first surface and / or the second surface.

4. The solar cell of claim 2, wherein, A first solder joint is provided on the first surface near the side cut surface; The length of the passivation layer extending on the first surface is less than or equal to the distance between the side section and the first solder joint, and / or the extension area of ​​the passivation layer on the first surface includes a colored area distributed close to the side section, the width of which is less than or equal to half the distance between the side section and the first solder joint.

5. The solar cell of claim 2, wherein, A second weld point is provided on the second surface adjacent to the side section; The length of the passivation layer extending on the second surface is less than or equal to the distance between the side section and the second solder joint, and / or, the extension region of the passivation layer on the second surface includes a colored region distributed close to the side section, the width of which is less than or equal to half the distance between the side section and the second solder joint.

6. The solar cell of claim 1, wherein, The protective layer extends from the side section and covers a portion of the first surface and / or a portion of the second surface of the battery cell body.

7. The solar cell of claim 6, wherein, The protective layer extends for 2 mm to 8 mm on the first surface and / or the second surface.

8. The solar cell of claim 6, wherein, A first solder joint is provided on the first surface adjacent to the side section, and the extension length of the protective layer on the first surface is less than or equal to the distance between the side section and the first solder joint; and / or, A second solder joint is provided on the second surface adjacent to the side section, and the extension length of the protective layer on the second surface is less than or equal to the distance between the side section and the second solder joint.

9. The solar cell of claim 1, wherein, The protective layer at least covers the passivation layer on the side section; and / or, The passivation layer has a thickness of 20 nm to 60 nm; and / or, The passivation layer located on the said side section has a uniform thickness; and / or, The thickness of the protective layer is 1 μm to 5 μm; and / or, The protective layer located on the side section has a uniform thickness.

10. A photovoltaic module, characterized by, Includes the solar cell as described in any one of claims 1-9.

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