Preparation method of solar cell, solar cell, assembly and photovoltaic system
By using a multi-cycle deposition technique involving TMA, water vapor, and ozone in an ALD device, the problem of unreacted methyl groups and aluminum sites in the alumina film was solved, resulting in improved alumina film density and battery efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-11
- Publication Date
- 2026-04-07
AI Technical Summary
In the preparation of alumina films, existing technologies often leave unreacted methyl groups and unsaturated aluminum sites, leading to passivation failure and affecting the density and efficiency of crystalline silicon solar cells.
Using TMA, water vapor, and ozone as precursors, multiple cycles of deposition are performed in an ALD device. The strong oxidizing properties of ozone oxidize the residual methyl groups on the surface and fill unsaturated aluminum sites to form a dense alumina film.
It improves the density of the alumina film and the efficiency of the battery cell, thereby enhancing the passivation effect and battery performance.
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Figure CN121815792A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of solar cell technology, and in particular to a method for preparing a solar cell, a solar cell, a module, and a photovoltaic system. Background Technology
[0002] Crystalline silicon solar cells are photovoltaic devices that convert light energy into electrical energy using the photovoltaic effect of a PN junction. Alumina film is a crucial passivation layer in crystalline silicon solar cells, possessing excellent passivation properties and chemical stability. Atomic layer deposition (ALD) technology is widely used in the preparation of alumina films.
[0003] However, when using atomic layer deposition (ALD) technology to prepare alumina films, unreacted methyl groups are easily left behind, affecting the film's density. Additionally, some unsaturated aluminum sites in the film layer can easily cause interface defects, leading to passivation failure and low cell efficiency. Summary of the Invention
[0004] This application proposes a method for preparing a solar cell, a solar cell, a module, and a photovoltaic system, which are used to improve the density of the alumina film and the cell efficiency.
[0005] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, a method for fabricating a solar cell is provided, the method comprising: providing a silicon substrate; performing a passivation pretreatment on the silicon substrate to form a silicon substrate to be passivated; and introducing a precursor into a first reaction chamber to form an alumina film on the silicon substrate to be passivated; the precursor includes TMA, water vapor, and ozone. This can improve the density of the alumina film and the cell efficiency.
[0006] Based on this scheme, after forming the silicon substrate to be passivated, TMA, water vapor, and ozone are introduced into the first reaction chamber. Since the strong oxidizing property of ozone can oxidize the residual methyl groups on the surface, the absence of methyl groups affects the density of the film, thus improving the density of the alumina film layer. In addition, the oxygen source provided by ozone fills the unsaturated aluminum sites, repairs the defects on the alumina surface, makes the alumina film layer denser, and improves the passivation effect and cell efficiency.
[0007] In conjunction with the first aspect, in some embodiments of the first aspect, a precursor is introduced into the first reaction chamber to form an alumina film on the silicon substrate to be passivated, including: performing multiple cycles to form an alumina film on the silicon substrate to be passivated when the first reaction chamber reaches the set reaction parameters; wherein the number of cycles is 10-80 times; a single cycle is to sequentially introduce TMA, purge gas, water vapor, purge gas, ozone, purge gas, and inert gas into the first reaction chamber.
[0008] In conjunction with the first aspect, in some embodiments of the first aspect, the flow rate of each precursor in a single cycle is 10 slm-30 slm; in some embodiments of the first aspect, the introduction time of each precursor in a single cycle is 10 s-50 s.
[0009] In conjunction with the first aspect, in some embodiments of the first aspect, the single purging time of the purge gas is 1-200 s.
[0010] In conjunction with the first aspect, in some embodiments of the first aspect, the reaction parameters include chamber temperature, chamber pressure, and isothermal duration.
[0011] In conjunction with the first aspect, in some embodiments of the first aspect, the chamber temperature is 100°C-300°C.
[0012] In conjunction with the first aspect, in some embodiments of the first aspect, the chamber pressure is 0.1 mbar to 0.8 mbar.
[0013] In conjunction with the first aspect, in some embodiments of the first aspect, the isothermal duration is 300s-1500s.
[0014] In conjunction with the first aspect, in some embodiments of the first aspect, the thickness of the alumina film is 2 nm-10 nm.
[0015] In conjunction with the first aspect, in some embodiments of the first aspect, after an aluminum oxide film is formed on the silicon substrate to be passivated, the method further includes: performing an annealing treatment in a second reaction chamber; the temperature of the second reaction chamber is 500°C-600°C.
[0016] In conjunction with the first aspect, in some embodiments of the first aspect, the annealing process lasts for 200s-1500s.
[0017] In conjunction with the first aspect, in some embodiments of the first aspect, a passivation pretreatment is performed on the silicon substrate to form a silicon substrate to be passivated, including: forming a tunneling layer on the silicon substrate; and forming a doped layer on the side of the tunneling layer opposite to the silicon substrate.
[0018] In conjunction with the first aspect, in some embodiments of the first aspect, after an aluminum oxide film is formed on the silicon substrate to be passivated, the method further includes: depositing a silicon nitride film, a silicon oxynitride film, and a silicon oxide film on the aluminum oxide film to form an anti-reflection passivation composite layer.
[0019] Secondly, the present invention provides a solar cell, which is made by the solar cell preparation method described above.
[0020] Thirdly, the present invention provides a solar cell module, which includes any of the possible solar cells described above.
[0021] Fourthly, the present invention provides a photovoltaic system comprising the solar cell module described above. Attached Figure Description
[0022] Figure 1 A schematic flowchart illustrating a method for fabricating a solar cell, provided as an embodiment of this application; Figure 2 A schematic flowchart illustrating another method for fabricating a solar cell provided in an embodiment of this application; Figure 3 A schematic flowchart illustrating another method for fabricating a solar cell provided in an embodiment of this application; Figure 4 This is a schematic flowchart illustrating another method for fabricating a solar cell provided in the embodiments of this application; Figure 5 This is a schematic diagram of the film structure of a solar cell provided as an embodiment of this application. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.
[0024] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "top", "bottom", "lateral", "longitudinal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0026] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0027] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0028] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0029] According to one aspect of this application, a method for preparing a solar cell is provided, such as... Figure 1 As shown, the method includes: S201, Provides a silicon substrate.
[0030] The silicon substrate can be a P-type silicon substrate or an N-type silicon substrate, and can be monocrystalline silicon or polycrystalline silicon, without restriction.
[0031] As one possible approach, after obtaining the original silicon substrate, the original silicon substrate can be cleaned to remove organic matter, metallic impurities, and particles from its surface, thus obtaining the silicon substrate.
[0032] In one example, the RCA standard cleaning method can be used to clean the raw silicon substrate.
[0033] S202. Perform passivation pretreatment on the silicon substrate to form the silicon substrate to be passivated.
[0034] One possible approach is to texturize the silicon substrate and form a tunneling layer on the silicon substrate after texturization, and then form a doped layer on the side of the tunneling layer away from the silicon substrate.
[0035] For example, a silicon substrate can be placed in a first texturing solution for preliminary alkaline texturing to obtain a texturized silicon substrate. The initial textured surface of the texturized silicon substrate is a dense and smooth pyramid structure.
[0036] Furthermore, a second texturing solution is used to texturize the monocrystalline silicon wafer after the initial cleaning, so as to form a texturized structure on the surface of the silicon substrate.
[0037] The first texturing solution includes a first alkaline solution and a first additive. The first alkaline solution may include, but is not limited to, one or more strongly alkaline solutions such as sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH4OH), or tetramethylhydroxylamine (TMAH). The second texturing solution includes at least a second alkaline solution, which may include, but is not limited to, one or more strongly alkaline solutions such as sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH4OH), or tetramethylhydroxylamine (TMAH).
[0038] The components of the first additive may include: surfactants, natural polysaccharide compounds, dispersants, emulsifiers, nucleating agents, chelating agents, naphthalene sulfonate formaldehyde condensates, inorganic bases, silicon reaction catalysts, and water.
[0039] It should be noted that the specific details of the pre-passivation treatment of the silicon substrate to form the silicon substrate to be passivated can be found in the following sections, and will not be repeated here.
[0040] S203. A precursor is introduced into the first reaction chamber to form an aluminum oxide film on the silicon substrate to be passivated.
[0041] The precursors include TMA, water vapor, and ozone. The first reaction chamber can be an ALD device chamber.
[0042] One possible approach is to set reaction parameters and, when the set reaction parameters are reached in the first reaction chamber, perform multiple cycles to form an aluminum oxide film on the silicon substrate to be passivated.
[0043] In this single cycle, TMA, purge gas, water vapor, purge gas, ozone, and purge gas are sequentially introduced into the first reaction chamber.
[0044] In one example, nitrogen can be used as a carrier gas to deliver TMA into the first reaction chamber, followed by purging with a purge gas. Water vapor can also be introduced into the first reaction chamber, followed by purging with a purge gas. Ozone can be introduced into the first reaction chamber, followed by purging with a purge gas; this constitutes one cycle. After multiple cycles, an aluminum oxide film is formed on the silicon substrate to be passivated.
[0045] As another possible implementation, reaction parameters can be set, and after the set reaction parameters are reached in the first reaction chamber and maintained for a preset time, multiple cycles can be performed to form an aluminum oxide film on the silicon substrate to be passivated.
[0046] Based on this scheme, after forming the silicon substrate to be passivated, TMA, water vapor, and ozone are introduced into the first reaction chamber. Since the strong oxidizing property of ozone can oxidize the residual methyl groups on the surface, the absence of methyl groups affects the density of the film, thus improving the density of the alumina film layer. In addition, the oxygen source provided by ozone fills the unsaturated aluminum sites, repairs the defects on the alumina surface, makes the alumina film layer denser, and improves the passivation effect and cell efficiency.
[0047] In some embodiments, the inflow rate of each precursor in a single cycle is 10 slm to 30 slm. For example, it can be any value between 10 slm, 15 slm, 20 slm, 25 slm, 30 slm or 10 slm to 30 slm, and there is no specific limitation herein.
[0048] In this way, the flow rate of each precursor in a single cycle is within an appropriate range. This can avoid the situation where the flow rate of each precursor in a single cycle is too small, which would result in slow and uneven growth of the alumina film and affect the passivation effect. It can also avoid the situation where the flow rate of each precursor in a single cycle is too large, which would result in waste of the precursor and the possibility that the film layer has already been formed due to the impact of the airflow, which would damage its structure. It could also complicate the reaction in the chamber and make it difficult to accurately control the film thickness and quality.
[0049] In some embodiments, the introduction time of each precursor in a single cycle is 10s-50s. For example, it can be any value between 10s, 20s, 30s, 40s, 50s or 10s-50s, and there is no specific limitation herein.
[0050] In this way, the introduction time of each precursor in a single cycle is within an appropriate range. This can avoid insufficient contact between the reactants and the silicon substrate due to the introduction time of each precursor being too short, resulting in incomplete growth of the alumina film, which is prone to defects such as pores and poor passivation effect. It can also avoid excessive reaction due to the introduction time of each precursor in a single cycle, which can lead to an excessively thick alumina film, generate internal stress, and cause the film layer to crack and fall off, affecting the battery performance and stability.
[0051] In some embodiments, the single purging time of the purge gas is 1s-200s. For example, it can be any value between 1s, 30s, 60s, 90s, 120s, 150s, 180s, 200s or 1s-200s, and there is no specific limitation here.
[0052] Thus, by keeping the single purging time of the purge gas within an appropriate range, it is possible to avoid situations where the single purging time is too short, resulting in ineffective removal of residual precursors in the chamber, which could easily lead to cross-contamination between different precursors, causing uneven alumina film composition and affecting the passivation effect of the silicon substrate. On the other hand, it is also possible to avoid situations where the single purging time of the purge gas is too long, which would prolong the overall process cycle and cause excessive fluctuations in environmental conditions such as temperature and pressure within the chamber, affecting the stability and consistency of subsequent precursor reactions, making it difficult to accurately control the quality of the alumina film, and thus reducing the product yield.
[0053] In some embodiments, the purging gas is an inert gas. For example, it can be nitrogen.
[0054] Understandably, nitrogen is chemically stable and does not readily react with precursors or the silicon substrate within the chamber, thus avoiding the introduction of impurities that could affect the quality of the alumina film. Furthermore, nitrogen is non-toxic and harmless, safe to use, and effectively removes residual reactants, ensuring a pure reaction environment. This allows for precise control of film growth and enhances the passivation effect on the silicon substrate.
[0055] In some embodiments, the number of cycles is 10-80. For example, it can be any value between 10, 20, 30, 40, 50, 60, 70, 80 or 10-80, and there is no specific limitation herein.
[0056] Thus, keeping the number of cycles within an appropriate range can avoid insufficient alumina film growth and thickness due to too few cycles, which would prevent effective passivation of the silicon substrate and make it difficult to meet the performance requirements of the battery, resulting in a decrease in product yield. It can also avoid excessive cycles, which would prolong the overall process cycle. Furthermore, excessive cycling may lead to an excessively thick alumina film, increased internal stress, and a tendency to crack and peel off, affecting the passivation effect.
[0057] In some embodiments, the reaction parameters include chamber temperature, chamber pressure, and isothermal duration.
[0058] In some embodiments, the chamber temperature is 100°C-300°C. For example, it can be any value between 100°C, 150°C, 200°C, 250°C, 300°C or 100°C-300°C, and there is no specific limitation herein.
[0059] In this way, the chamber temperature is kept within a suitable range. This can prevent the chamber temperature from being too low, which would result in insufficient reactivity of the precursors, making it difficult to react fully, slow and uneven growth of the alumina film, and difficulty in achieving the required film thickness and performance, ultimately affecting the overall quality of the silicon substrate to be passivated. It can also prevent the chamber temperature from being too high, which would lead to accelerated thermal decomposition of the precursors, increased risk of runaway reaction, easy generation of impurity particles, rough and porous alumina film, and reduced passivation effect.
[0060] In some embodiments, the chamber pressure is 0.1 mbar to 0.8 mbar. For example, it can be any value between 0.1 mbar, 0.2 mbar, 0.3 mbar, 0.4 mbar, 0.5 mbar, 0.6 mbar, 0.7 mbar, 0.8 mbar or 0.1 mbar to 0.8 mbar, and there is no specific limitation herein.
[0061] In this way, the chamber pressure is kept within a suitable range. This can prevent the precursor molecules from being too dense due to excessively low chamber pressure, resulting in insufficient reactivity, slow growth of the alumina film, or even failure to form a continuous and dense film layer, which would affect the passivation effect of the silicon substrate. It can also prevent the precursor molecules from colliding too much due to excessively high chamber pressure, which would lead to an overly violent reaction that is difficult to control precisely, resulting in uneven growth of the alumina film, agglomeration, and may also increase the risk of impurity contamination.
[0062] In some embodiments, the isothermal duration is 300s-1500s. For example, it can be any value between 300s, 400s, 500s, 600s, 700s, 800s, 900s, 1000s, 1100s, 1200s, 1300s, 1400s, 1500s or 300s-1500s, and there is no specific limitation here.
[0063] Thus, keeping the isothermal duration within a suitable range can avoid reducing equipment utilization and overall production efficiency and increasing time costs due to excessively long isothermal durations, and can also avoid unstable and uneven chamber temperatures due to excessively short isothermal durations, which would fail to provide suitable conditions for precursor reactions, resulting in poor quality alumina film preparation and difficulty in achieving the expected passivation effect.
[0064] In some embodiments, the thickness of the alumina film is 2nm-10nm. For example, it can be any value between 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm or 2nm-10nm, and there is no specific limitation here.
[0065] Thus, maintaining an appropriate alumina film thickness avoids the following: an excessively thick film would significantly increase internal stress, leading to cracking and peeling during subsequent processing or use, thus affecting passivation durability. Conversely, an excessively thick film might hinder charge transport and reduce device performance. Conversely, an excessively thin film would prevent the formation of a continuous, dense protective layer, hindering the effective blocking of impurity ions and failing to adequately passivate silicon wafer surface defects, resulting in a significant decrease in the stability and reliability of silicon-based devices.
[0066] In some embodiments, such as Figure 2 As shown, after forming an aluminum oxide film on the silicon substrate to be passivated, this application may further include the following steps: S301, Annealing is performed in the second reaction chamber.
[0067] The second reaction chamber can be a PECVD device.
[0068] The temperature of the second reaction chamber is 500℃-600℃. For example, it can be any value between 500℃, 520℃, 540℃, 560℃, 580℃, 600℃ or 500℃-600℃, and there is no specific limitation here.
[0069] Thus, maintaining the temperature of the second reaction chamber within a suitable range avoids excessively high temperatures that could lead to hydrogen release during high-temperature annealing, causing bubble bursts and poor passivation. It also avoids excessively low temperatures that could result in insufficient atomic activity, hindering the effective elimination of defects and stresses in the alumina film, making it difficult to optimize film quality, and preventing the annealing process from fully realizing its role in improving silicon wafer performance.
[0070] As one possible approach, after the alumina film is formed on the silicon substrate to be passivated, the alumina-coated silicon substrate to be passivated can be placed in a graphite boat and sent to the second reaction chamber. The temperature of the second reaction chamber is raised to a certain temperature and maintained for a certain time to complete the annealing process.
[0071] In some embodiments, the annealing process lasts for 200s-1500s. For example, it can be any value between 200s, 400s, 600s, 800s, 1000s, 1200s, 1400s, 1500s or 200s-1500s, and there is no specific limitation here.
[0072] Therefore, keeping the annealing time within an appropriate range can prevent excessively long annealing times from causing internal thermal stress accumulation, which could lead to bending and deformation of the silicon wafer, affecting its flatness. Conversely, excessively short annealing times can result in insufficient elimination of defects and stress within the film, leading to inadequate optimization of the alumina film performance, difficulty in achieving the desired passivation effect, and reduced silicon wafer quality.
[0073] In some embodiments, such as Figure 3 As shown, in order to perform pre-passivation treatment on the silicon substrate to form the silicon substrate to be passivated, S202 in this application may specifically include the following steps: S401, A tunneling layer is formed on a silicon substrate.
[0074] As one possible approach, a wet processing method can be used to process the silicon substrate and grow an oxide layer (such as silicon oxide) on the wet-processed silicon substrate to prepare a tunneling layer on the silicon substrate.
[0075] For example, a tunneling layer can be prepared by reacting a silicon substrate with oxygen or water vapor at a high temperature using a thermal oxidation method to generate silicon dioxide, thereby growing an oxide layer (such as silicon oxide) on the wet-processed silicon substrate.
[0076] For example, silicon oxide can be generated by decomposing a gaseous precursor on the surface of a silicon substrate to grow an oxide layer (such as silicon oxide) on a wet-processed silicon substrate, thus preparing a tunneling layer.
[0077] The wet processing can include a pretreatment stage and a main etching stage.
[0078] For example, organic matter, metallic impurities, and natural oxide layers on the surface of the silicon substrate can be removed during the pretreatment stage, and the silicon substrate can be etched during the main etching stage.
[0079] It should be noted that the specific process for removing organic matter, metallic impurities and natural oxide layers from the surface of the silicon substrate, as well as the specific process for etching the silicon substrate during the main etching stage, can be referred to existing technologies and will not be elaborated here.
[0080] Understandably, by preparing a tunneling layer, interfacial recombination loss can be reduced, the open-circuit voltage and fill factor of the cell can be improved, thereby enhancing the photoelectric conversion efficiency of the cell.
[0081] S402, A doped layer is formed on the side of the tunneling layer away from the silicon substrate.
[0082] The doped layer can be a doped polycrystalline silicon layer.
[0083] One possible approach is to place the silicon substrate with the prepared tunneling layer in a reaction chamber and introduce silane gas into the reaction chamber to deposit a doped polycrystalline silicon layer on the side of the tunneling layer away from the silicon substrate, thus forming a doped layer.
[0084] In one example, the reaction chamber can be an LPCVD equipment chamber or a PECVD equipment chamber.
[0085] The doped layer may include a first polarity doped layer and a second polarity doped layer with different doping polarities.
[0086] The first polar doped layer and the second polar doped layer are respectively a P-doped layer and an N-doped layer.
[0087] The P-doped layer and N-doped layer can be doped polycrystalline silicon layers. The N-doped layer is doped with an N-type element, specifically a group VA element of the periodic table, such as phosphorus. The P-doped layer is doped with a P-type element, specifically a group IIIA element of the periodic table, such as boron.
[0088] In some embodiments, such as Figure 4 As shown, after forming an aluminum oxide film on the silicon substrate to be passivated, this application may further include the following steps: S501. A silicon nitride film, a silicon oxynitride film, and a silicon oxide film are deposited on an alumina film to form an anti-reflection passivation composite layer.
[0089] Among them, the silicon nitride film is located on the side of the aluminum oxide film away from the silicon substrate, the silicon oxynitride film is located on the side of the silicon nitride film away from the silicon substrate, and the silicon oxide film is located on the side of the silicon oxynitride film away from the silicon substrate.
[0090] One possible approach is to place a silicon substrate coated with an alumina film in a PECVD apparatus and introduce silane and ammonia gas into the PECVD apparatus to deposit a silicon nitride film on the alumina film.
[0091] Furthermore, silane, ammonia, and nitrogen oxides can be introduced into the PECVD equipment to deposit a silicon oxynitride film on the silicon nitride film.
[0092] Furthermore, silane and nitric oxide can be introduced into the PECVD equipment to deposit a silicon oxide film on the silicon oxynitride film, thereby forming an anti-reflection passivation composite layer including an alumina film, a silicon nitride film, a silicon oxynitride film, and a silicon oxide film.
[0093] Understandably, the anti-reflection passivation composite layer has both anti-reflection and passivation functions, which can significantly improve light absorption rate, reduce surface recombination rate, enhance battery stability, and extend service life. While improving photoelectric conversion efficiency, it also has excellent weather resistance and reliability.
[0094] Subsequently, an etching material is formed on the anti-reflection passivation composite layer to etch the area to be metallized on the passivation layer, exposing the doped layer, or the doped layer is exposed by laser molding, and a gate structure is formed on the exposed doped layer.
[0095] For example, an etching material can be formed in the passivation layer to cover the area to be metallized, and the passivation layer of the area to be metallized can be etched to expose the doped layer.
[0096] It should be noted that the gate line structure is electrically connected to the doped layer, and the gate line structure can be formed on the exposed doped layer through methods such as screen printing.
[0097] It should be noted that when this method is applied to bifacial solar cells, the structure described above can be the entire structure of the cell; when this method is applied to back-contact solar cells, the structure described above can be a partial P-region structure or N-region structure of the cell, and no limitation is made here.
[0098] It needs to be explained that, Figure 5 The diagram shows the film structure of a back-contact solar cell 10, with the P-region and N-region located on the same side of the silicon substrate. The silicon substrate 11 includes a front side and a back side opposite to the front side. The front side of the silicon substrate 11 is the light-facing side of the back-contact solar cell 10, and the back side is the back-facing side. Both the P-region and N-region are located on the back side of the silicon substrate. The front side of the back-contact solar cell 10 has a textured surface and includes an anti-reflection passivation composite layer 14. The anti-reflection passivation composite layer 14, in the direction away from the silicon substrate 11, includes an aluminum oxide film 141, a silicon nitride film 142, a silicon oxynitride film 143, and a silicon oxide film 144 in sequence. The back side of the back-contact solar cell 10 also includes an anti-reflection passivation composite layer 14, and in the direction away from the silicon substrate 11, the anti-reflection passivation composite layer on the back side includes an aluminum oxide film 141, a silicon nitride film 142, a silicon oxynitride film 143, and a silicon oxide film 144 in sequence.
[0099] The doped layer includes a first doped layer 131 and a second doped layer 132, which are alternately arranged on the back side of the silicon substrate 11. The first doped layer 131 can be an N-doped layer and the second doped layer 132 can be a P-doped layer; or the first doped layer 131 can be a P-doped layer and the second doped layer 132 can be an N-doped layer; the P-region and the N-region are isolated by an isolation region.
[0100] As a preferred embodiment, an N-type TBC battery is used, and its film structure is as shown above. Figure 5 As shown, the specific preparation method is as follows: 1. Perform passivation pretreatment on the silicon substrate to form the silicon substrate to be passivated.
[0101] 2. Place the silicon substrate to be passivated in the ALD chamber, set the temperature to 200℃, evacuate to 0.2mbar, and then hold the temperature for 900s.
[0102] 3. Using nitrogen as a carrier, TMA was introduced into the chamber at a flow rate of 20 slm for 18 seconds. Then, high-purity nitrogen was introduced to purge the furnace tubes for 30 seconds. Water vapor was then introduced into the chamber at a flow rate of 10 slm for 18 seconds, followed by another 30 seconds of high-purity nitrogen purging. Ozone was then introduced at a flow rate of 20 slm for 20 seconds, followed by another 30 seconds of high-purity nitrogen purging. This constituted one cycle. This cycle was repeated 40 times to produce alumina with a thickness of 5 nm.
[0103] IV. Annealing pretreatment using PECVD furnace tube: The alumina-coated silicon wafer is loaded into a graphite boat, sent into the furnace tube, and the furnace tube temperature is raised to 580℃ and held for 1200s.
[0104] 5. Prepare the anti-reflection passivation composite layer, then sinter and test.
[0105] It should be noted that the performance test results of the solar cells prepared in this application (hereinafter referred to as the experimental group in the table) and the solar cells prepared in the prior art (hereinafter referred to as the control group in the table) are shown in Table 1.
[0106] Table 1 As shown in Table 1, the passivation fitting efficiency of the solar cells improved by 0.035%.
[0107] 1 SUN represents 1 standard solar radiation intensity, 0.1 SUN represents 0.11 standard solar radiation intensity, Uoc represents open circuit voltage, FF represents fill factor, and Eta represents conversion efficiency.
[0108] It is understood that in such embodiments, the photovoltaic module corresponding to the solar cell may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film can be filled between the front and back of the solar cell, as well as between the photovoltaic glass and adjacent cells. As a filler, it can be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film can be EVA film or POE film, and the specific choice can be made according to the actual situation, without limitation.
[0109] Photovoltaic glass can be applied to the encapsulating film on the front of solar cells. This photovoltaic glass can be ultra-clear glass, characterized by high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, ultra-clear glass can achieve a light transmittance of over 92%, protecting the solar cells while minimizing impact on their efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the solar cells together, providing sealing, insulation, and waterproofing / moisture protection for the solar cells.
[0110] The backsheet can be attached to the encapsulating film on the back of the solar cell. The backsheet protects and supports the solar cell, providing reliable insulation, water resistance, and aging resistance. Multiple backsheet options are available, typically including tempered glass, acrylic glass, and aluminum alloy TPT composite encapsulating film, etc., depending on the specific circumstances and not limited here. The backsheet, solar cell, encapsulating film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire battery module, providing stable support and installation. For example, the battery module can be installed at the desired location using the metal frame.
[0111] The photovoltaic system of this application embodiment includes the photovoltaic module described above.
[0112] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.
[0113] In the description of this specification, the references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0114] Furthermore, the above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. A method for preparing a solar cell, characterized in that, The method includes: Provide silicon substrate; The silicon substrate is subjected to a passivation pretreatment to form a silicon substrate to be passivated; A precursor is introduced into the first reaction chamber to form an alumina film on the silicon substrate to be passivated; the precursor includes TMA, water vapor, and ozone.
2. The preparation method according to claim 1, characterized in that, The process of introducing a precursor into the first reaction chamber to form an alumina film on the silicon substrate to be passivated includes: When the set reaction parameters are reached in the first reaction chamber, multiple cycles are performed to form an aluminum oxide film on the silicon substrate to be passivated. The number of cycles is 10-80 times; a single cycle consists of sequentially introducing TMA, purge gas, water vapor, purge gas, ozone, and purge gas into the first reaction chamber, wherein the purge gas is an inert gas.
3. The preparation method according to claim 2, characterized in that, The flow rate of each of the precursors in a single cycle is 10 slm-30 slm; the introduction time of each of the precursors in a single cycle is 10 s-50 s.
4. The preparation method according to claim 2, characterized in that, The single purging time of the purging gas is 1s-200s.
5. The preparation method according to claim 2, characterized in that, The set reaction parameters include chamber temperature, chamber pressure, and isothermal duration.
6. The preparation method according to claim 5, characterized in that, The temperature of the chamber is 100℃-300℃.
7. The preparation method according to claim 5, characterized in that, The chamber pressure is 0.1 mbar to 0.8 mbar.
8. The preparation method according to claim 5, characterized in that, The constant temperature duration is 300s-1500s.
9. The preparation method according to claim 2, characterized in that, The thickness of the alumina film is 2nm-10nm.
10. The preparation method according to claim 1, characterized in that, After forming an aluminum oxide film on the silicon substrate to be passivated, the method further includes: Annealing is performed in the second reaction chamber; the temperature of the second reaction chamber is 500℃-600℃.
11. The preparation method according to claim 10, characterized in that, The annealing process lasts for 200s-1500s.
12. The preparation method according to claim 1, characterized in that, The process of performing a passivation pretreatment on the silicon substrate to form the silicon substrate to be passivated includes: A tunneling layer is formed on the silicon substrate; A doped layer is formed on the side of the tunneling layer opposite to the silicon substrate.
13. The preparation method according to claim 1, characterized in that, After forming an aluminum oxide film on the silicon substrate to be passivated, the method further includes: A silicon nitride film, a silicon oxynitride film, and a silicon oxide film are deposited on the alumina film to form an anti-reflection passivation composite layer.
14. A solar cell, characterized in that, The solar cell is manufactured using the preparation method described in any one of claims 1-13.
15. A solar cell module, characterized in that, Including the solar cell as described in claim 14.
16. A photovoltaic system, characterized in that, Includes the solar cell module as described in claim 15.