Ultraviolet attenuation resistant TOPCon battery and preparation method thereof

Abstract

The invention discloses an ultraviolet attenuation resistant TOPCon cell and a preparation method thereof, a passivation layer is arranged close to the light incident side of the TOPCon cell, the passivation layer at least comprises a SiNX / AlOX two-layer structure, AlOX is arranged on the inner layer, and an Al and F co-doped CeOX layer is arranged on the passivation layer. According to the invention, through co-doping of Al and F, the oxygen vacancy concentration in cerium oxide crystal lattices is controlled, so that the absorption of a CeOX thin layer to a visible light wave band is inhibited; a doped cerium oxide thin layer and SiNX / AlOX are adopted to form a laminated film structure, and the laminated film structure is applied to the front surface of the TOPCon battery, so that the ultraviolet resistance of the TOPCon battery is improved, and the performance degradation of the battery caused by ultraviolet is reduced; the UV attenuation effect of the TOPCon battery is obviously reduced, and meanwhile, the adopted sol-gel method and other process preparation methods are convenient and easy to implement, so that the production efficiency is improved, the cost is reduced, and large-scale popularization and application are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic cells, and in particular to a TOPCon cell resistant to ultraviolet attenuation and a preparation method thereof. Background Art

[0002] With the development of photovoltaic technology, n-type tunneling oxide passivated contact (TOPCon) cell technology, with its higher power generation efficiency, has rapidly replaced p-type emitter rear passivated (PERC) cells and become the mainstream in the industry. However, with the large-scale commercialization of TOPCon cells, the problem of ultraviolet-induced degradation (UV degradation) has gradually emerged.

[0003] The Renewable Energy Testing Center (RETC), an internationally recognized testing organization, has released the "2024 Photovoltaic Module Index Report." According to RETC standards, any maximum power degradation greater than or equal to 5% is considered a red light result. UV degradation testing results show that 40% of TOPCon module samples displayed red light warning signals. Among them, some module samples already in mass production and commercial use also exhibited double-digit power losses. This indicates that these products may experience a 10%-16% degradation within the first three years of power plant operation, far exceeding the <5% degradation level of traditional PERC modules. Double-digit degradation would also far exceed the module warranty terms and PV system power guarantee limits. Therefore, the development of UV-resistant TOPCon technology has become an urgent industry need.

[0004] The cause of UV-induced degradation of TOPCon solar modules is still under investigation, and there is no clear explanation within the industry. Currently, there are several theories: 1) Passivation layer interface recombination: Ultraviolet photons (energy > 3.5 eV) destroy the Si-H bonds at the passivation film / Si interface, resulting in an increase in the interface state density and intensified carrier recombination; 2) Interface defect activation: UV radiation activates Si / SiO X Metastable defects at the interface, while changing the SiN X The refractive index of the anti-reflection layer causes fluctuations in the module output power; 3) The sensitivity cost of high conversion efficiency: High-efficiency cell design improves photoelectric conversion efficiency, but at the same time makes it more sensitive to various types of attenuation.

[0005] Existing technologies are primarily focused on optimizing UV blocking and passivation layers. For example, the research and development center of Yida New Energy Technology Co., Ltd. published a study titled "Study of UV Attenuation of n-Type TOPCon Photovoltaic Modules Based on Operating Condition Simulation," which indicates that UV cutoff films can effectively block the effects of UV light on photovoltaic cells. Invention patent CN119177059 B discloses an ultraviolet (UV) light conversion coating for photovoltaic cells. This coating converts UV light into visible light, reducing UV wavelength transmittance and increasing visible wavelength transmittance, thereby minimizing the effects of UV light on the cell. Typical UV blocking methods, whether using UV cutoff films or UV conversion, block UV light below 380nm. However, TOPCon cells typically respond to light between 330-1200nm, and UV cutoff can reduce their power generation efficiency.

[0006] Invention patent CN118571957 B discloses a TOPCon cell front film with UV attenuation resistance and its preparation method. Using atomic layer deposition (ALD), a multilayer aluminum oxide film, a stacked silicon oxynitride film, and regrown silicon nitride and silicon oxynitride passivation films are deposited, thereby enhancing chemical passivation and field passivation, thereby reducing the UV attenuation effect of the TOPCon cell. However, ALD deposition is very slow, and the patent utilizes a multilayer stacking method, which is inefficient and has high production costs, making it difficult to promote and use on a large scale. Summary of the Invention

[0007] The purpose of the present invention is to provide a TOPCon cell that is resistant to ultraviolet attenuation, and to prepare CeO doped by a sol-gel method. X Cerium oxide thin layer with SiN X / AlO X (Silicon nitride / aluminum oxide) forms a stacked film structure to improve the UV resistance of TOPCon batteries; and the sol-gel method has extremely low process costs and has good market promotion prospects.

[0008] To achieve the above purpose, the present invention designs a TOPCon cell that is resistant to ultraviolet attenuation. A passivation layer is provided near the light-entering side of the TOPCon cell. The passivation layer comprises at least SiN X / AlO X Two-layer structure (SiN X It is a representation of silicon nitride, AlO X Aluminum oxide is a way of expressing aluminum oxide. Aluminum oxide is in the inner layer near the light-entering side of the cell). AlO X In the inner layer, the passivation layer is provided with Al (aluminum) and F (fluorine) co-doped CeO X (Cerium Oxide) layer, forming CeO X / SiNX / AlO X Laminated film structure, the Al and F co-doped CeO X The thin layers were prepared by the sol-gel method.

[0009] Furthermore, the sol-gel method includes: CeO X The sol is spin-coated, blade-coated or dip-coated on the silicon wafer, dried at 80-120°C for 5-10 minutes, kept at 250-350°C for 10-20 minutes, and kept at 500-600°C for 5-10 minutes.

[0010] Furthermore, the sol-gel method further comprises configuring CeO X Sol, the CeO X The components of the sol include: 3.0-6.0 parts of cerium source, 0.5-2.0 parts of aluminum source, 0.05-1.0 parts of fluorine source, 30.0-50.0 parts of deionized water, 3.0-8.0 parts of chelating agent, 30.0-50.0 parts of solvent and 1.0-2.0 parts of stabilizer.

[0011] The total number of all components is 100 parts, and various stoichiometric ratios of CeO are prepared by adjusting the proportions of each component. X Thin layer.

[0012] Furthermore, the cerium source includes one or a combination of cerium nitrate, cerium sulfate, cerium chloride, cerium acetate, cerium acetylacetonate, and ammonium cerium nitrate.

[0013] Furthermore, the aluminum source includes one or a combination of aluminum nitrate and aluminum sulfate.

[0014] Furthermore, the fluorine source includes one or more of ammonium fluoride and ammonium bifluoride.

[0015] Furthermore, the chelating agent includes one or a combination of several of disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, sodium citrate, sodium diethylenetriaminepentaacetate, sodium nitrilotriacetate, sodium gluconate, tartaric acid, 8-hydroxyquinoline, and acetylacetone.

[0016] Furthermore, the solvent includes one or a combination of methanol, ethanol, n-propanol, isopropanol, ethylene glycol, propylene glycol, glycerol, and acetone.

[0017] Furthermore, the stabilizer includes one or a combination of n-octyldimethylamine, 2-aminoethanol, and tetraethylammonium hydroxide.

[0018] On the other hand, a method for preparing a TOPCon cell resistant to ultraviolet attenuation comprises the following steps: S1. Preparation of CeO XSol: Add the cerium source to deionized water, stir thoroughly until completely dissolved, then add the aluminum source and fluorine source in turn, stir thoroughly until completely dissolved; then add the solvent and chelating agent in proportion, stir at 40-60°C for 2-4 hours, add the stabilizer and stir at room temperature for 12-24 hours.

[0019] S2, TOPCon battery preparation, including S21, cleaning and velveting; S22, front surface boron diffusion; S23, depositing a tunneling oxide layer and a polysilicon layer on the back surface; S24, back surface phosphorus diffusion; S25, passivation layer preparation; S26. Preparation of Al and F co-doped CeO by sol-gel method X thin layer; S27, screen printing and sintering; Alternatively, the above step S26 is performed after S27, i.e., after the battery is prepared, CeO is applied to the front surface of the battery. X Preparation of thin layers; The passivation layer preparation includes first preparing an aluminum oxide layer by atomic layer deposition (ALD), and then preparing a silicon nitride layer by plasma enhanced chemical vapor deposition (PECVD); The Al and F co-doped CeO X The method for preparing the thin layer includes: X Sol spin coating, blade coating or dip coating on the front surface SiN X On the outside, dry at 80-120℃ for 5-10min, keep warm at 250-350℃ for 10-20min, and keep warm at 500-600℃ for 5-10min.

[0020] In the present invention, CeO X The thin layer preparation method can also be used on the surface of BC cells (Back Contact Solar Cell) or other high-temperature process solar cells to resist UV attenuation, and can also be directly used on the light-receiving surface of photovoltaic glass or other packaging materials to resist UV attenuation.

[0021] The advantages and beneficial effects of the present invention are that, while significantly reducing the UV attenuation effect of the TOPCon battery, the sol-gel method and other convenient preparation methods are adopted, thereby improving production efficiency, reducing costs, and facilitating large-scale promotion and application. The specific advantages and beneficial effects are as follows: 1. Sol-gel method is used to dope cerium oxide. By co-doping with Al and F, the oxygen vacancy concentration in the cerium oxide lattice is controlled, thereby inhibiting the growth of CeO X The absorption of visible light by thin layers; 2. Using doped cerium oxide thin layer with SiN X / AlO X Forming a laminated film structure for the front surface of TOPCon cells, improving the UV resistance of TOPCon cells and reducing the degradation of cell performance caused by UV rays; 3. Ultraviolet cut-off materials and down-conversion materials can also suppress the UVID (ultraviolet attenuation) phenomenon of TOPCon cells, but the material cost is relatively high; UVID can also be suppressed to a certain extent by adjusting the multi-layer film composite structure, but the production efficiency of coating equipment such as ALD or PECVD is relatively low. The present invention adopts the sol-gel method to carry out CeO X Thin layer preparation has high efficiency and low cost, which is convenient for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the main process flow for preparing the TOPCon battery of the present invention. DETAILED DESCRIPTION

[0023] The following embodiments are further described in conjunction with the accompanying drawings and examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0024] Cerium oxide (CeO X As a stable inorganic material, cerium oxide (Cerium Oxide) is an ideal passivation material for photovoltaic cells. Its band gap is approximately 3.1-3.3 eV, making it a wide-bandgap semiconductor. It exhibits virtually no intrinsic absorption of visible light (photon energies 1.6-3.1 eV), resulting in high transparency. Its dielectric constant (ε≈24-26) is significantly higher than that of traditional silicon nitride (ε≈7-8) and aluminum oxide (ε≈9-10), effectively shielding surface charge and reducing potential-induced decay (PID). However, oxygen vacancies easily form in the cerium oxide lattice, affecting its absorption in the visible light range. Therefore, Cerium Oxide must be doped to reduce the oxygen vacancy concentration.

[0025] In order to further compare and illustrate the superiority of the TOPCon battery and its preparation method of the present invention, this application selects 4 comparative examples, all of which are existing technologies or slightly adjusted based on the existing technologies.

[0026] Comparative Example 1: Same as the commercially available TOPCon battery, without CeO X The aluminum oxide passivation layer is prepared by ALD method, and the silicon nitride passivation layer is prepared by PEVCD method.

[0027] Comparative Example 2: Pure CeO X Thin layer, but undoped: 1) Preparation of cerium oxide sol: Add 5 g of cerium nitrate (cerium source) to 42 g of deionized water and stir thoroughly to dissolve completely. Add 45 g of ethanol (solvent) and 6 g of tetrasodium ethylenediaminetetraacetate (chelating agent), stir at 40-60°C for 2-4 h. Add 2 g of octyldimethylamine (stabilizer) and stir at room temperature for 24 h.

[0028] 2) The preparation process of TOPCon battery is the same as that of Comparative Example 1, except that the passivation layer is prepared by first preparing the aluminum oxide layer by ALD method, then preparing the silicon nitride layer by PECVD method, and finally preparing CeO by sol-gel method. X Thin layer (in this case pure CeO2); 3) Among them, CeO X The thin layer preparation method is to prepare the CeO X The sol was spin-coated on a silicon wafer by coating CeO X The sol was dripped onto the battery surface and spin-coated at 800 rpm for 3 seconds before accelerating to 2500 rpm for 30 seconds. After spin coating, the surface was dried at 120°C for 5 minutes, then kept at 250°C for 20 minutes and 500°C for 5 minutes.

[0029] Comparative Example 3: Setting Al-doped CeO X Thin layer: 1) Prepare cerium oxide sol: Add 5g of cerium nitrate (cerium source) to 40.5g of deionized water and stir thoroughly until completely dissolved. Then, add 1.5g of aluminum nitrate (aluminum source) and stir thoroughly until completely dissolved. Add 45g of ethanol (solvent) and 6g of tetrasodium ethylenediaminetetraacetate (chelating agent). Stir at 40-60°C for 2-4 hours. Add 2g of octyldimethylamine (stabilizer) and stir at room temperature for 24 hours.

[0030] 2) The preparation process of TOPCon battery is the same as that of Comparative Example 1, except that the passivation layer is prepared by first preparing an aluminum oxide layer by ALD, then preparing a silicon nitride layer by PECVD, and finally preparing Al-doped CeO by sol-gel method. X thin layer; 3) Al-doped CeO X The thin layer preparation method is to prepare the CeO X The sol was spin-coated on a silicon wafer by coating CeO X The sol was dripped onto the battery surface and spin-coated at 800 rpm for 3 seconds before accelerating to 2500 rpm for 30 seconds. After spin coating, the surface was dried at 120°C for 5 minutes, then kept at 250°C for 20 minutes and 500°C for 5 minutes.

[0031] Comparative Example 4: Setting F-doped CeO X Thin layer: 1) Prepare cerium oxide sol: Add 5g of cerium nitrate (cerium source) to 41.5g of deionized water and stir thoroughly until completely dissolved. Add 0.5g of ammonium fluoride (fluorine source) and stir thoroughly until completely dissolved. Add 45g of ethanol (solvent) and 6g of tetrasodium ethylenediaminetetraacetate (chelating agent). Stir at 40-60°C for 2-4 hours. Add 2g of octyldimethylamine (stabilizer) and stir at room temperature for 24 hours.

[0032] 2) The preparation process of TOPCon battery is the same as that of comparative example 1, except that the passivation layer is prepared by first preparing the aluminum oxide layer by ALD method, then preparing the silicon nitride layer by PECVD method, and finally preparing the F-doped CeO by sol-gel method. X thin layer; 3) F-doped CeO X The thin layer preparation method is to prepare the CeO X The sol was spin-coated on a silicon wafer by coating CeO X The sol was dripped onto the battery surface and spin-coated at 800 rpm for 3 seconds before accelerating to 2500 rpm for 30 seconds. After spin coating, the surface was dried at 120°C for 5 minutes, then kept at 250°C for 20 minutes and 500°C for 5 minutes.

[0033] Example 1: The present invention is a TOPCon cell that is resistant to ultraviolet attenuation. A passivation layer is provided near the light-entering side of the TOPCon cell. The passivation layer comprises at least SiN X / AlO X (Silicon Nitride / Aluminum Oxide) two-layer structure (where SiN X It is a representation of silicon nitride, AlO X Aluminum oxide is a way of expressing aluminum oxide. Aluminum oxide is in the inner layer near the light-entering side of the cell). AlO X In the inner layer, the passivation layer is provided with Al (aluminum) and F (fluorine) co-doped CeO X (Cerium Oxide) layer, forming CeO X / SiNx / Al2O3 stacked film structure, the Al and F co-doped CeO X The thin layers were prepared by the sol-gel method.

[0034] CeO X The film is co-doped with Al and F. Al doping can improve the hardness. The improved hardness can avoid defects caused by wear on the battery surface during welding and circulation, and improve the battery yield; F doping can improve the density, reduce the defects and recombination caused by oxygen vacancies in cerium oxide itself, and improve the passivation effect. Al and F co-doping improves the film forming properties. Although F doping can improve the density, CeO XWhen doped with F alone, the film forming property is poor and the appearance deteriorates, but after adding Al, the film forming property becomes better.

[0035] Preferably, the sol-gel method comprises: X The sol is spin-coated, blade-coated or dip-coated on the silicon wafer, and then 1) Drying at 80-120℃ for 5-10min: Preliminary drying to remove solvents and moisture, avoid direct high temperature drying, and avoid problems such as micro cracks, blistering, shedding, defects, etc. caused by uneven gel shrinkage; 2) Keep at 250-350℃ for 10-20min: decompose residual organic ligands (such as citric acid) and eliminate hydroxyl groups (-OH) to prevent holes or stress cracking caused by violent decomposition at high temperature; 3) Keep at 500-600℃ for 5-10min: Densification is achieved after the organic matter is completely removed, the grain size is more controllable, and the film density is significantly improved.

[0036] The above three-step method can achieve uniform and dense CeO X Co-doped thin films.

[0037] Preferably, the sol-gel method further comprises configuring CeO X Sol, the CeO X The components of the sol include: 3.0-6.0 parts of cerium source, 0.5-2.0 parts of aluminum source, 0.05-1.0 parts of fluorine source, 30.0-50.0 parts of deionized water, 3.0-8.0 parts of chelating agent, 30.0-50.0 parts of solvent and 1.0-2.0 parts of stabilizer.

[0038] The total number of all components is 100 parts, and various stoichiometric ratios of CeO are prepared by adjusting the proportions of each component. X Thin layer. The proportion of the above components is determined mainly based on the following analysis and considerations: Cerium source 3.0-6.0 parts: As the main material for cerium oxide film formation, less than 3.0 parts will result in an incomplete cerium oxide film layer and an inability to form a uniform cerium oxide film. More than 6.0 parts will result in too little co-doping ratio of Al and F, and the ideal hardness and density requirements cannot be achieved.

[0039] Aluminum source 0.5-2.0 parts: Al doping can improve the hardness of cerium oxide film. The addition of aluminum source >2.0 parts will affect the transmittance of the film, and the transmittance will decrease. The refractive index of AlO is higher than that of CeO. X Low, also causes the refractive index of the film to decrease, which will affect the power generation efficiency of the photovoltaic cell, and less doping will result in unsatisfactory hardness.

[0040] Fluorine source 0.05-1.0 parts: F doping can improve the density of the film and enhance the passivation effect. The addition of more than 1.0 parts of fluorine source may cause the original lattice structure of cerium oxide to be destroyed, thereby affecting the film formation effect of cerium oxide, deteriorating the appearance (such as microcracks), and even making it impossible to form a film.

[0041] 30.0-50.0 parts of deionized water: controls the hydrolysis rate to avoid premature gelation of the sol (too little water will cause cracking); too much water will make it difficult to form a film.

[0042] 3.0-8.0 parts of chelating agent: The function of the chelating agent is to delay the polycondensation reaction and improve the stability of the sol. Too little chelating agent will result in insufficient sol stability and easy agglomeration; too much chelating agent will reduce the density of the film and reduce the transmittance after high-temperature sintering.

[0043] 30.0-50.0 parts solvent: The organic solvent and water work together to promote uniform film formation. Too much organic solvent will dry too quickly, resulting in poor film formation. Too little organic solvent will dry too slowly, also reducing film formation. Furthermore, an optimal organic solvent / water ratio can maintain the stability of the entire system.

[0044] Stabilizer: 1.0-2.0 parts: Inhibits particle aggregation and maintains system stability. Too little stabilizer can easily cause the system to aggregate and the gel to break. Too much stabilizer can affect film-forming properties and transmittance after film formation.

[0045] Preferably, the cerium source includes one or a combination of cerium nitrate, cerium sulfate, cerium chloride, cerium acetate, cerium acetylacetonate, and ammonium cerium nitrate.

[0046] Preferably, the aluminum source includes one or a combination of aluminum nitrate and aluminum sulfate.

[0047] Preferably, the fluorine source includes one or more of ammonium fluoride and ammonium bifluoride.

[0048] Preferably, the chelating agent includes one or a combination of disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, sodium citrate, sodium diethylenetriaminepentaacetate, sodium nitrilotriacetate, sodium gluconate, tartaric acid, 8-hydroxyquinoline, and acetylacetone.

[0049] Preferably, the solvent includes one or a combination of methanol, ethanol, n-propanol, isopropanol, ethylene glycol, propylene glycol, glycerol, and acetone.

[0050] Preferably, the stabilizer includes one or a combination of n-octyldimethylamine, 2-aminoethanol, and tetraethylammonium hydroxide.

[0051] Specific 1) Preparation of cerium oxide sol: Add 5 g of cerium nitrate (cerium source) to 40 g of deionized water and stir thoroughly until completely dissolved. Then, add 1.5 g of aluminum nitrate (aluminum source) and 0.5 g of ammonium fluoride (fluorine source) and stir thoroughly until completely dissolved. Add 45 g of ethanol (solvent) and 6 g of tetrasodium ethylenediaminetetraacetate (chelating agent) and stir at 40-60°C for 2-4 h. Add 2 g of octyldimethylamine (stabilizer) and stir at room temperature for 24 h.

[0052] 2) The preparation process of TOPCon battery is the same as that of comparative example 1, except that the passivation layer is prepared by first preparing an aluminum oxide layer by ALD method, then preparing a silicon nitride layer by PECVD method, and finally preparing Al and F co-doped CeO by sol-gel method. X thin layer; 3) CeO co-doped with Al and F X The thin layer preparation method is to spin-coat the cerium oxide sol obtained above on the silicon wafer. X The sol was dripped onto the battery surface and spin-coated at 800 rpm for 3 seconds before accelerating to 2500 rpm for 30 seconds. After spin coating, the surface was dried at 120°C for 5 minutes, then kept at 250°C for 20 minutes and 500°C for 5 minutes.

[0053] Example 2: A method for preparing a TOPCon battery resistant to ultraviolet attenuation comprises the following steps: S1. Preparation of CeO X Sol: Add the cerium source to deionized water, stir thoroughly until completely dissolved, then add the aluminum source and fluorine source in turn, stir thoroughly until completely dissolved; then add the solvent and chelating agent in proportion (in no particular order), stir at 40-60°C for 2-4 hours, add the stabilizer and stir at room temperature for 12-24 hours.

[0054] S2, TOPCon battery preparation, such as Figure 1 Shown, including S21, cleaning and velveting; S22, front surface boron diffusion; S23, depositing a tunneling oxide layer and a polysilicon layer on the back surface; S24, back surface phosphorus diffusion; S25, passivation layer preparation; S26. Preparation of Al and F co-doped CeO by sol-gel method X thin layer; S27, screen printing and sintering; The passivation layer preparation includes first preparing an aluminum oxide layer by atomic layer deposition (ALD), and then preparing a silicon nitride layer by plasma enhanced chemical vapor deposition (PECVD); Specific 1) Prepare cerium oxide sol: Add 4.5g of cerium acetate (cerium source) to 39.7g of deionized water and stir thoroughly until completely dissolved. Then, add 2g of aluminum nitrate (aluminum source) and 0.8g of ammonium fluoride (fluorine source) and stir thoroughly until completely dissolved. Add 45g of ethanol (solvent) and 7g of tetrasodium ethylenediaminetetraacetate (chelating agent). Stir at 40-60°C for 2-4 hours. Add 1g of 2-aminoethanolamine (stabilizer) and stir at room temperature for 24 hours.

[0055] 2) The preparation process of TOPCon battery is the same as that of comparative example 1, except that after the battery is sintered, Al and F co-doped CeO is prepared by sol-gel method. X thin layer; 3) CeO co-doped with Al and F X The thin layer preparation method is to prepare the CeO X The sol is coated on the silicon wafer by scraping CeO X The sol was dripped onto the coating head. The gap between the coating blade and the cell was adjusted to 150μm. The blade and substrate were moved relative to each other at a coating speed of 1cm / s. After coating, the coating was left to stand at room temperature for 20 minutes until the film on the cell surface was evenly leveled. After standing, the coating was dried at 120°C for 5 minutes, then kept at 250°C for 20 minutes and 500°C for 5 minutes.

[0056] The batteries in the comparative example and the embodiment were encapsulated using a double-glass method, with high-transmittance films used for both the front and rear films. After encapsulation, the power of the small components and the power of the components after UV aging were tested.

[0057] The test results are as follows: Use Cases composition Battery pencil hardness <![CDATA[CeO X Thin film appearance]]> <![CDATA[CeO X Thin layer refractive index]]> Solar cell efficiency <![CDATA[UV120kWh / m 2 Post-Power Decay]]> Comparative Example 1 <![CDATA[Without CeO X thin layer]]> 4H intact / 25.0% 5.3% Comparative Example 2 <![CDATA[CeO X Thin layer without doping]]> 4H intact 2.2 24.2% 2.3% Comparative Example 3 <![CDATA[Al-doped CeO X thin film]]> 5H intact 2.2 24.4% 1.7% Comparative Example 4 <![CDATA[F-doped CeO X thin film]]> 4H There are microcracks 2.3 24.6% 1.5% Example 1 <![CDATA[Al, F co-doped CeO X thin layer]]> 5H intact 2.3 24.8% 1.2% Example 2 <![CDATA[Al, F co-doped CeO X thin layer]]> 5H intact 2.3 24.7% 1.1% The above test results show that the Al and F co-doped CeO X Thin layer stacking SiNx / AlO X The passivation layer is used for TOPCon cell passivation. Compared with comparative examples 1 and 2, the pencil hardness of Examples 1 and 2 is increased from 4H to 5H, indicating that the hardness and wear resistance of the cell are improved. In this way, when the photovoltaic cell is welded in a string welding machine, the damage to the cell surface passivation layer caused by the assembly line operation can be reduced. X The presence of oxygen vacancies in the film affects the solar transmittance, so increasing CeO X After the thin layer, the efficiency of the solar cell decreases, but by doping with Al or F, the oxygen vacancy concentration is reduced, thereby reducing its visible light absorption, and the efficiency of the solar cell is improved; CeO X The refractive index of the thin layer increases from 2.2 to 2.3, indicating that CeO X The refractive index density of the thin layer is further improved, which can further improve the UV stability. UV 120kWh / m2 After irradiation, the power decayed, and the attenuation of the comparative example reached 5.3%, while that of Examples 1 and 2 was less than 1.2%, indicating that the Al and F co-doped CeO X Thin layer can reduce the battery performance degradation caused by ultraviolet rays.

[0058] Compared with the four comparative examples, the overall performance of Example 2 is significantly improved and is similar to that of Actual Example 1.

[0059] Example 3: The difference from Example 2 is: S26, screen printing and sintering; S27, Preparation of Al and F co-doped CeO by sol-gel method X thin layer; That is, after the battery body is prepared, CeO is deposited on the front surface of the battery. X Preparation of thin layers; The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the technical principles of the present invention, several improvements and modifications can be made, including the composition ratio of cerium oxide sol, drying process and parameter selection, etc. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A TOPCon battery resistant to ultraviolet attenuation, characterized in that: A passivation layer is provided near the light-entering side of the TOPCon cell, and the passivation layer comprises at least SiN X / AlO X Two-layer structure, AlO X In the inner layer, the passivation layer is provided with Al and F co-doped CeO X layer, forming CeO X / SiN X / AlO X Laminated film structure, the Al and F co-doped CeO X The thin layers were prepared by the sol-gel method.

2. The TOPCon cell resistant to ultraviolet attenuation according to claim 1, characterized in that: The sol-gel method comprises: X The sol is spin-coated, blade-coated or dip-coated on the silicon wafer, dried at 80-120°C for 5-10 minutes, kept at 250-350°C for 10-20 minutes, and kept at 500-600°C for 5-10 minutes.

3. The TOPCon cell resistant to ultraviolet attenuation according to claim 2, characterized in that: The sol-gel method further comprises configuring CeO X Sol, the CeO X The components of the sol include: 3.0-6.0 parts of cerium source, 0.5-2.0 parts of aluminum source, 0.05-1.0 parts of fluorine source, 30.0-50.0 parts of deionized water, 3.0-8.0 parts of chelating agent, 30.0-50.0 parts of solvent and 1.0-2.0 parts of stabilizer.

4. The TOPCon cell resistant to ultraviolet attenuation according to claim 3, characterized in that: The cerium source includes one or a combination of cerium nitrate, cerium sulfate, cerium chloride, cerium acetate, cerium acetylacetonate, and ammonium cerium nitrate.

5. The TOPCon cell resistant to ultraviolet attenuation according to claim 3, characterized in that: The aluminum source includes one or a combination of aluminum nitrate and aluminum sulfate.

6. The TOPCon cell resistant to ultraviolet attenuation according to claim 3, characterized in that: The fluorine source includes one or more of ammonium fluoride and ammonium bifluoride.

7. The TOPCon cell resistant to ultraviolet attenuation according to claim 3, characterized in that: The chelating agent includes one or a combination of disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, sodium citrate, sodium diethylenetriaminepentaacetate, sodium nitrilotriacetate, sodium gluconate, tartaric acid, 8-hydroxyquinoline, and acetylacetone.

8. The TOPCon cell resistant to ultraviolet attenuation according to claim 3, characterized in that: The solvent includes one or a combination of methanol, ethanol, n-propanol, isopropanol, ethylene glycol, propylene glycol, glycerol, and acetone.

9. The TOPCon cell resistant to ultraviolet attenuation according to claim 3, characterized in that: The stabilizer includes one or a combination of n-octyldimethylamine, 2-aminoethanol, and tetraethylammonium hydroxide.

10. A method for preparing a TOPCon battery resistant to ultraviolet attenuation, characterized in that: The steps include: S1. Preparation of CeO X Sol: Add the cerium source to deionized water, stir thoroughly until completely dissolved, then add the aluminum source and fluorine source in sequence, stir thoroughly until completely dissolved; then add the solvent and chelating agent in proportion, stir at 40-60°C for 2-4 hours, add the stabilizer and stir at room temperature for 12-24 hours; S2, TOPCon battery preparation, including S21, cleaning and velveting; S22, front surface boron diffusion; S23, depositing a tunneling oxide layer and a polysilicon layer on the back surface; S24, back surface phosphorus diffusion; S25, passivation layer preparation; S26. Preparation of Al and F co-doped CeO by sol-gel method X thin layer; S27, screen printing and sintering; Alternatively, the above step S26 is performed after S27; The passivation layer preparation includes first preparing an aluminum oxide layer by atomic layer deposition, and then preparing a silicon nitride layer by plasma enhanced chemical vapor deposition; The Al and F co-doped CeO X The method for preparing the thin layer includes: X Sol spin coating, blade coating or dip coating on the front surface SiN X On the outside, dry at 80-120℃ for 5-10min, keep warm at 250-350℃ for 10-20min, and keep warm at 500-600℃ for 5-10min.

Images