Solar cell and preparation method thereof, photovoltaic module and photovoltaic system

Abstract

The invention is suitable for the technical field of solar cells, and provides a solar cell and a preparation method thereof, a photovoltaic module and a photovoltaic system, different preparation materials can be arranged for a series connection structure and a connecting line to respectively correspond to the requirements of the series connection structure and the connecting line, and the performance of the solar cell is improved. Comprising a silicon substrate; the main grid is arranged on the silicon substrate and comprises a plurality of series connection structures and connecting lines, and the connecting lines are arranged between every two adjacent series connection structures; the preparation material of the serial connection structure comprises a first metal material, and the preparation material of the connecting line comprises a second metal material.

Description

Technical Field

[0001] This application belongs to the field of solar cell technology, and particularly relates to a solar cell and its preparation method, a photovoltaic module and a photovoltaic system. Background Technology

[0002] In fabricating solar cell metal electrodes, to ensure good conductivity and weldability, a single metal material is typically printed onto the electrode. However, a single metal material may not simultaneously meet the optimal performance requirements of different regions of the solar cell metal electrode. For example, region 1 may have performance requirement 'a', while region 2 may have performance requirement 'b'. A single metal material might meet the minimum requirements of 'a' and 'b', but it is not optimal. Summary of the Invention

[0003] This application provides a solar cell and its preparation method, a photovoltaic module and a photovoltaic system, aiming to solve the problem of how to improve the performance of the metal electrode of a solar cell.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] In a first aspect, a solar cell is provided, comprising: a silicon substrate; a main grid disposed on the silicon substrate, including a plurality of series structures and connecting lines, the connecting lines being disposed between two adjacent series structures; the series structures are made of a first metallic material, and the connecting lines are made of a second metallic material.

[0006] In some embodiments, the first metallic material is silver.

[0007] In some embodiments, the second metallic material is a base metal.

[0008] In some embodiments, the base metal is one or more of copper and aluminum.

[0009] In some embodiments, multiple welding zones are spaced apart along the length of the welding strip.

[0010] In a second aspect, the present invention provides a method for fabricating a solar cell, comprising: providing a silicon substrate; fabricating a series structure on the silicon substrate using a first metal material; and fabricating a connecting line on the silicon substrate using a second metal material, wherein the connecting line is disposed between two adjacent series structures to form a main grid.

[0011] In some embodiments, the first metallic material is silver.

[0012] In some embodiments, the second metallic material is a base metal.

[0013] In some embodiments, the base metal is one or more of copper and aluminum.

[0014] In some embodiments, a serial connection structure is fabricated on a silicon substrate using a first metal material, including: printing a first pattern corresponding to the serial connection structure on the silicon substrate using the first metal material; and sintering the printed first pattern to obtain the serial connection structure.

[0015] In some embodiments, fabricating a connecting line on a silicon substrate using a second metal material includes: printing a second pattern corresponding to the connecting line on the silicon substrate using the second metal material; and sintering the printed second pattern to obtain the connecting line.

[0016] In some embodiments, prior to the step of fabricating interconnects on a silicon substrate using a second metal material, the method further includes: fabricating a sub-gate on a silicon substrate using a first metal material.

[0017] In some embodiments, a sub-gate is fabricated on a silicon substrate using a first metal material, including: printing a third pattern corresponding to the sub-gate on the silicon substrate using the first metal material; and sintering the printed third pattern to obtain the sub-gate.

[0018] In some embodiments, the sintering temperature of the series structure is greater than the sintering temperature of the connecting wire.

[0019] Thirdly, the present invention provides a solar cell, which is made by the solar cell preparation method described above.

[0020] Fourthly, the present invention provides a photovoltaic module, which includes any of the possible solar cells described above.

[0021] Fifthly, the present invention provides a photovoltaic system, which includes the photovoltaic modules described above.

[0022] The beneficial effects of this invention are as follows:

[0023] The solar cells, fabrication method, photovoltaic modules, and photovoltaic systems of this application, in which the fabrication material for the series structure includes a first metal material and the fabrication material for the connecting wires includes a second metal material, allow for different fabrication materials for the series structure and connecting wires, thus addressing the specific needs of each and improving the performance of the solar cells. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a solar cell provided in an embodiment of this application;

[0025] Figure 2 This is a schematic diagram of the structure of a solar cell provided in another embodiment of this application;

[0026] Figure 3 This is a schematic flowchart of a method for preparing a solar cell according to an embodiment of this application;

[0027] Figure 4 This is a schematic flowchart of a method for preparing a solar cell according to another embodiment of this application;

[0028] Figure 5 This is a schematic flowchart of a method for preparing a solar cell according to another embodiment of this application;

[0029] Figure 6 This is a schematic flowchart of a method for preparing a solar cell according to another embodiment of this application.

[0030] Explanation of key component symbols: 100, solar cell; 110, silicon substrate; 120, main grid; 121, series connection; 122, connecting line; 130, sub-grid. Detailed Implementation

[0031] 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.

[0032] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] Please see Figure 1 and Figure 2 This application provides a solar cell 100, comprising:

[0038] Silicon substrate 110;

[0039] The main gate 120 is located on the silicon substrate 110 and includes several series structures 121 and connecting lines 122, with the connecting lines 122 located between two adjacent series structures 121.

[0040] The material used to fabricate the series structure 121 includes a first metallic material, and the material used to fabricate the connecting wire 122 includes a second metallic material.

[0041] The solar cell 100, its fabrication method, photovoltaic module, and photovoltaic system of this application embodiment utilize a first metal material for the fabrication of the series structure 121 and a second metal material for the fabrication of the connecting wire 122. By using different fabrication materials for the series structure 121 and the connecting wire 122, the requirements of each can be addressed, thereby improving the performance of the solar cell 100.

[0042] The main gate 120 may include an N-region main gate and a P-region main gate.

[0043] It should be noted that a secondary gate 130 is also provided on the surface of the silicon substrate 110. The main gate 120 and the secondary gate 130 are arranged perpendicularly and intersectingly. The secondary gate 130 is used to collect current in the polarity region, and the gate lines of opposite polarities are arranged alternately. Specifically, the secondary gate 130 includes a P-region secondary gate for collecting current in the first polarity region and a secondary gate for collecting current in the second polarity region. The polarities of the P-region secondary gate and the N-region secondary gate are opposite, and the polarities of the first polarity region and the second polarity region are also opposite. The P-region main gate is connected to the P-region secondary gate and spaced apart from the N-region secondary gate, and the N-region main gate is connected to the secondary gate and spaced apart from the P-region secondary gate.

[0044] Among them, the series connection structure 121 connects the solder strip, conductive wire and other series components.

[0045] It should be noted that, since the series structure 121 needs to provide tensile strength and conductivity, the performance requirements for the metal material of the series structure 121 are high weld strength and strong conductivity. The connecting wire 122 is used to collect and transmit charge carriers and does not need to provide tensile strength, but it needs to have low resistance to ensure excellent current transmission performance. That is, the performance requirement for the metal material of the connecting wire 122 is strong conductivity.

[0046] In practical applications, the serial connection structure 121 can be a PAD point.

[0047] In some embodiments, the first metallic material is silver.

[0048] Understandably, by setting the first metal material to silver, the high conductivity of silver and the high mechanical strength of the corresponding welding points can ensure the strong welding of the main grid 120 to the welding strip.

[0049] In practical applications, the materials used to prepare the tandem structure 121 may also include adhesives, solvents, and additives; the adhesives, solvents, additives, and silver can be mixed to form a silver paste, and the tandem structure 121 can be prepared based on the silver paste.

[0050] In some embodiments, the second metallic material is a base metal.

[0051] For example, base metals can be one or more of copper and aluminum.

[0052] Understandably, by setting the second metal material to a base metal, since the connecting line 122 is used to collect and transport charge carriers, it is not necessary to provide tension between the solder strip and the main gate 120. Instead, it needs to have low resistance to ensure excellent conductivity. Therefore, by using a base metal with good conductivity but poor solderability to replace the connecting line 122, it is not necessary to consider the relevant performance of the solder joint strength, but only the conductivity. At the same time, the base metal has a lower cost, which can reduce the manufacturing cost of the metal electrode.

[0053] In practical applications, the materials used to prepare the connector 122 may also include adhesives, solvents, and additives; the adhesives, solvents, additives, and base metals may be mixed to form a base metal slurry, and the connector 122 may be prepared based on the base metal slurry.

[0054] For example, base metal pastes can be copper paste, silver-coated copper, etc.

[0055] In some embodiments, the distance between two adjacent serial structures 121 is 50-100mm. In such embodiments, the distance between two adjacent serial structures 121 can be any value between 50mm, 60mm, 70mm, 80mm, 90mm, 100mm or 50mm-100mm, and is not specifically limited herein.

[0056] Thus, setting the distance between two adjacent series structures 121 to between 50-100mm ensures that the distance between them is within a suitable range, which reduces resistance loss on the one hand, and improves the connection stability between the solder ribbon and the battery cell on the other.

[0057] In some embodiments, the number of serial structures 121 in a single main gate 120 can be 1, 2, 3, 4, 5, etc., and no specific limitation is made here.

[0058] This increases the strength of the mechanical connection and reduces the risk of the weld strip falling off or cracking.

[0059] According to one aspect of this application, a method for preparing a solar cell 100 is provided, such as... Figure 3 As shown, the preparation method for preparing the above-mentioned solar cell 100 includes:

[0060] S201, Provides silicon substrate 110.

[0061] The silicon substrate 110 can be a P-type silicon substrate or an N-type silicon substrate, and can be monocrystalline silicon or polycrystalline silicon, without limitation.

[0062] As one possible approach, after obtaining the original silicon substrate 110, the original silicon substrate 110 can be cleaned to remove organic matter, metal impurities and particles from the surface of the original silicon substrate 110, thereby obtaining the silicon substrate 110.

[0063] In one example, the raw silicon substrate 110 can be cleaned using the RCA standard cleaning method.

[0064] S202, Using a first metallic material, a series structure 121 is fabricated on a silicon substrate.

[0065] The cascaded structure 121 can be a PAD point. The first metallic material can be silver. In practical applications, the materials used to prepare the cascaded structure 121 can also include binders, solvents, and additives; the binders, solvents, additives, and silver can be mixed to form a silver paste. The silicon substrate can be pre-marked.

[0066] As one possible implementation, the silicon substrate 110 can be placed on a screen printing platform, and the silicon substrate of the silicon substrate 110 can be aligned with the mesh lines of the screen printing stencil. A first metal material can be laid on the screen printing stencil, and the screen printing squeegee can be held vertically against the mesh lines and scraped along the mesh line direction with a preset pressure, so that the silver paste passes through the mesh lines and is printed on the silicon substrate to form a series structure 121.

[0067] In one example, a silicon substrate 110 can be placed on a screen printing platform, silver paste can be laid on a screen printing stencil, and a screen printing squeegee can be held vertically against the mesh lines and scraped along the mesh line direction with a preset pressure, so that the silver paste passes through the mesh lines and is printed on the silicon substrate to form a serial structure 121.

[0068] It should be noted that the preset pressure can be 30-70N. In such an embodiment, the preset pressure can be any value between 30N, 40N, 50N, 60N, 70N or 30-70N, and there is no specific limitation here.

[0069] In this way, the preset pressure is within a suitable range, which can ensure that the slurry fully fills the mesh without overflowing.

[0070] In some embodiments, the interconnect structure 121 can also be fabricated on a silicon substrate using a first metal material by methods such as vacuum evaporation, electroplating, and magnetron sputtering, which are not limited here.

[0071] In practical applications, before fabricating the serial structure 121 on the silicon substrate, a tunneling layer, a doped layer, and a passivation layer can be prepared on the silicon substrate.

[0072] S203. Using a second metallic material, a connecting wire 122 is fabricated on a silicon substrate.

[0073] The connecting line 122 is located between two adjacent series structures 121 to form the main grid 120.

[0074] The second metallic material is a base metal. In practical applications, the materials used to prepare the connecting wire 122 may also include adhesives, solvents, and additives; the adhesives, solvents, additives, and base metals can be mixed to form a base metal slurry.

[0075] As one possible implementation, the silicon substrate 110 can be placed on a screen printing platform, the second metal material can be laid on the screen printing stencil, the screen printing squeegee is held vertically against the mesh lines and scraped along the mesh line direction with a preset pressure, so that the second metal material passes through the mesh lines and is printed on the silicon substrate to create the connecting line 122. Then, the connecting line 122 and the serial structure 121 form the main gate 120.

[0076] For example, a silicon substrate 110 can be placed on a screen printing platform, base metal paste can be laid on a screen printing stencil, and a screen printing squeegee can be held vertically against the mesh lines and scraped along the mesh line direction with a preset pressure, so that the base metal paste passes through the mesh lines and is printed on the silicon substrate to create a connecting line 122. Then, the connecting line 122 and the serial structure 121 form a main gate 120.

[0077] In the solar cell 100, its fabrication method, photovoltaic module, and photovoltaic system of this application embodiment, the material used to fabricate the series structure 121 on the silicon substrate includes a first metal material, and the material used to fabricate the connecting line 122 on the silicon substrate includes a second metal material. Thus, by using different fabrication materials for the series structure 121 and the connecting line 122, the difficulty of determining the optimal solution for the performance requirements of different regions of the metal electrode of the solar cell 100 can be reduced.

[0078] In some embodiments, such as Figure 4 As shown, in order to fabricate the serial structure 121 on the silicon substrate using the first metal material, step S202 in this embodiment specifically includes:

[0079] S301. Print the first pattern corresponding to the serial structure 121 on the silicon substrate using the first metal material.

[0080] As one possible implementation, a screen printing device can be provided with a first target screen printing stencil installed, and a first metal material can be laid on the first target screen printing stencil of the screen printing device. Furthermore, the screen printing squeegee of the screen printing device holds the mesh line vertically and scrapes along the mesh line direction with a preset pressure, accurately printing through the hollow pattern area of ​​the first target screen printing stencil onto the silicon substrate of the silicon substrate 110 to form the first pattern corresponding to the serial structure 121.

[0081] It should be noted that the cutout pattern on the first target screen printing plate is the first pattern (e.g., an array of circular or square pad dots).

[0082] It should be noted that the printing speed of the first pattern corresponding to the serial structure 121 printed on the silicon substrate using the first metal material can be 100-650 mm / s. For example, it can be any value between 100 mm / s, 200 mm / s, 300 mm / s, 400 mm / s, 500 mm / s, 600 mm / s, 650 mm / s, or 100-650 mm / s, and no specific limitation is made here.

[0083] In this way, the integrity and consistency of the first printed graphic can be guaranteed while ensuring printing speed.

[0084] S302. The first printed pattern is sintered to obtain the serial structure 121.

[0085] As one possible implementation, a sintering apparatus can be provided, in which the silicon substrate 110 with the first pattern printed is placed and sintered based on a preset temperature profile to obtain the serial structure 121.

[0086] It should be noted that the peak sintering temperature of the series structure 121 can be 650-800℃. For example, it can be any value between 650℃, 680℃, 700℃, 720℃, 740℃, 750℃, 760℃, 780℃, 800℃ or 650℃-800℃, and there is no specific limitation here.

[0087] This allows for the formation of excellent ohmic contacts. At high temperatures, the metal materials fuse to form a continuous and dense three-dimensional conductive network, which significantly reduces the resistance of the electrode grid lines and minimizes ohmic losses during current transmission within the grid lines.

[0088] The preset temperature curve may include a preheating stage, a burn-out stage, a high-temperature sintering stage, and a cooling stage.

[0089] For example, the temperature range for the preheating stage can be room temperature to 400°C. The temperature range for the burn-out stage can be 400°C to 500°C. The temperature range for the high-temperature sintering stage can be 700°C to 800°C. The temperature range for the cooling stage can be 800°C to room temperature.

[0090] The preheating stage can be between 30 and 90 seconds, for example, it can be any value between 30, 40, 50, 60, 70, 80, or 90 seconds; there is no specific limitation. Too short a time will result in insufficient solvent evaporation, leading to boiling in subsequent stages; too long a time will affect production efficiency. Therefore, by setting a reasonable preheating stage time range, the organic solvent can be fully evaporated while ensuring production efficiency.

[0091] The burnout phase can be between 30 and 60 seconds, for example, any value between 30, 40, 50, 60 seconds, or 30-60 seconds; no specific limit is imposed here. Too short a time will result in insufficient removal of the polymer; too long a time will affect production efficiency. Therefore, by setting a reasonable burnout phase time range, the polymer can be fully removed while ensuring production efficiency.

[0092] The time range of the high-temperature sintering stage can be 1s-5s, for example, it can be any value between 1s, 2s, 3s, 4s, 5s or 1s-5s, and there is no specific limitation here. In this way, by setting a reasonable time range for the burn-out stage, excellent ohmic contact can be formed, overburning can be avoided, and the risk of silicon wafer damage can be reduced.

[0093] The cooling phase can range from 60s to 120s, for example, it can be any value between 60s, 70s, 80s, 90s, 100s, 110s, 120s, or 60s-120s, without any specific limitation. In this way, by setting a reasonable cooling phase time range, the risk of microcracks in the silicon wafer caused by thermal stress due to excessively rapid cooling can be reduced.

[0094] As another possible implementation, a drying device and a sintering device can be provided. The silicon substrate 110 with the printed first pattern is placed in the drying device for drying, and after drying, the silicon substrate 110 with the printed first pattern is placed in the sintering device for sintering based on a preset temperature curve to obtain the serial structure 121.

[0095] This pre-drying process allows the organic solvents in the paste to evaporate, ensuring the conductivity of the paste after sintering. It also prevents the paste from being rubbed off during subsequent printing, thus ensuring the integrity of the first pattern.

[0096] In some embodiments, such as Figure 5 As shown, in order to fabricate the interconnect 122 on the silicon substrate using the second metal material, step S203 in this embodiment specifically includes:

[0097] S401. A second pattern corresponding to the connecting line 122 is printed on a silicon substrate using a second metal material.

[0098] As one possible implementation, a screen printing device with a second target screen printing stencil installed can be provided, and a second metal material can be laid on the second target screen printing stencil of the screen printing device. Furthermore, the screen printing squeegee of the screen printing device holds the mesh line vertically and scrapes along the mesh line direction with a preset pressure, accurately printing through the hollow pattern area of ​​the second target screen printing stencil onto the silicon substrate of the silicon substrate 110 to form a second pattern corresponding to the connecting line 122.

[0099] It should be noted that the cutout pattern on the second target screen printing plate is the second pattern.

[0100] It should be noted that the printing speed of the second pattern corresponding to the connecting line 122 on the silicon substrate using the second metal material can be referenced to the printing speed of the first pattern mentioned above.

[0101] S402. Sinter the printed second pattern to obtain connecting line 122.

[0102] As one possible implementation, a sintering apparatus can be provided, in which the silicon substrate 110 with the printed second pattern is placed and sintered based on a preset temperature profile to obtain the connecting line 122.

[0103] It should be noted that the sintering temperature of the series structure 121 is greater than that of the connecting wire 122.

[0104] In one example, the peak sintering temperature of the connecting wire 122 can be between 100°C and 300°C. For example, it can be any value between 100°C, 150°C, 200°C, 250°C, 300°C, or 100°C and 300°C, without any specific limitation.

[0105] Since base metals are temperature-sensitive and easily oxidize at high temperatures, leading to decreased conductivity, low-temperature sintering is necessary for curing. Setting the peak sintering temperature of the connecting wire 122 between 100℃ and 300℃ not only ensures the curing effect of the connecting wire 122 but also improves its conductivity.

[0106] The preset temperature curve may include a preheating stage, a burn-out stage, a high-temperature sintering stage, and a cooling stage.

[0107] For example, the temperature range for the preheating stage can be room temperature to 400°C. The temperature range for the burn-out stage can be 400°C to 500°C. The temperature range for the high-temperature sintering stage can be 700°C to 800°C. The temperature range for the cooling stage can be 800°C to room temperature.

[0108] The preheating stage can be between 30 and 90 seconds, for example, it can be any value between 30, 40, 50, 60, 70, 80, or 90 seconds; there is no specific limitation. Too short a time will result in insufficient solvent evaporation, leading to boiling in subsequent stages; too long a time will affect production efficiency. Therefore, by setting a reasonable preheating stage time range, the organic solvent can be fully evaporated while ensuring production efficiency.

[0109] The burnout phase can be between 30 and 60 seconds, for example, it can be any value between 30, 40, 50, 60 seconds, or 30-60 seconds; there is no specific limitation here. Too short a time will result in insufficient removal of polymers; too long a time will affect production efficiency. Therefore, by setting a reasonable burnout phase time range, polymers can be fully removed while ensuring production efficiency.

[0110] The time range of the high-temperature sintering stage can be 1s-5s, for example, it can be any value between 1s, 2s, 3s, 4s, 5s or 1s-5s, and there is no specific limitation here. In this way, by setting a reasonable time range for the burn-out stage, excellent ohmic contact can be formed, overburning can be avoided, and the risk of silicon wafer damage can be reduced.

[0111] The cooling phase can range from 60s to 120s, for example, it can be any value between 60s, 70s, 80s, 90s, 100s, 110s, 120s, or 60s-120s, without any specific limitation. In this way, by setting a reasonable cooling phase time range, the risk of microcracks in the silicon wafer caused by thermal stress due to excessively rapid cooling can be reduced.

[0112] As another possible implementation, a drying device and a sintering device can be provided. The silicon substrate 110 with the printed first pattern is placed in the drying device for drying, and after drying, the silicon substrate 110 with the printed first pattern is placed in the sintering device for sintering based on a preset temperature curve to obtain the serial structure 121.

[0113] This pre-drying process allows the organic solvents in the paste to evaporate, ensuring the conductivity of the paste after sintering. It also prevents the paste from being rubbed off during subsequent printing, thus ensuring the integrity of the first pattern.

[0114] In some embodiments, prior to the step of fabricating the interconnect 122 on the silicon substrate using a second metallic material, this application further includes:

[0115] S501. A sub-gate 130 is fabricated on a silicon substrate using a first metallic material.

[0116] The subgate 130 may include a P-region subgate and an N-region subgate.

[0117] As one possible implementation, the third pattern corresponding to the printed sub-gate 130 on the silicon substrate can be obtained by sintering the printed third pattern.

[0118] As another possible implementation, the third pattern corresponding to the printed sub-gate 130 on the silicon substrate can be obtained by using the first metal material, drying the printed third pattern, and sintering the dried third pattern.

[0119] In this way, the sub-gate 130 is fabricated before the step of fabricating the connecting line 122. The fabrication materials of both the sub-gate 130 and the main gate 120 are the first metal material, and there is no need to change the fabrication material midway, which can improve the fabrication efficiency.

[0120] In some embodiments, the printed first pattern can be sintered together with the P-region sub-gate and N-region sub-gate after drying. This can save sintering costs and fabrication time of the solar cell 100, and improve fabrication efficiency.

[0121] In practical applications, the printed first pattern, after drying, can be sintered together with the sub-gate 130. This saves sintering costs and solar cell fabrication time, improving fabrication efficiency.

[0122] In some embodiments, in order to fabricate the sub-gate 130 on the silicon substrate using the first metal material, S501 in this application embodiment specifically includes:

[0123] S601, The third pattern corresponding to the printed sub-gate 130 on the silicon substrate using the first metal material.

[0124] The subgate 130 may include a P-region subgate and an N-region subgate.

[0125] As one possible implementation, the P-region sub-gate and the N-region sub-gate can be printed simultaneously. In the case of simultaneous printing of the P-region sub-gate and the N-region sub-gate, a screen printing device equipped with a third target screen printing stencil can be provided. The first metal material is laid on the third target screen printing stencil of the screen printing device. Furthermore, the screen printing squeegee of the screen printing device holds the mesh line vertically and scrapes along the mesh line direction with a preset pressure. Through the hollow pattern area of ​​the third target screen printing stencil, it is accurately printed on the silicon substrate of the silicon substrate 110 to form the third pattern corresponding to the sub-gate 130.

[0126] It should be noted that the cutout pattern on the third target screen printing stencil is the third pattern. The silicon substrate of the silicon substrate 110 corresponds one-to-one with the mesh lines of the third target screen printing stencil.

[0127] As one possible implementation, the P-region sub-gate and N-region sub-gate can be printed in steps. In the case of step-by-step printing of the P-region sub-gate and N-region sub-gate, a screen printing device equipped with a fourth target screen printing stencil can be provided. The first metal material is laid on the fourth target screen printing stencil of the screen printing device. Furthermore, the screen printing squeegee of the screen printing device holds the mesh line vertically and scrapes along the mesh line direction with a preset pressure. Through the hollow pattern area of ​​the fourth target screen printing stencil, it is accurately printed on the sub-gate corresponding area of ​​the silicon substrate 110 to form the pattern corresponding to the sub-gate. Then, it is dried and sintered to produce the sub-gate. Furthermore, a screen printing device equipped with a fifth target screen printing stencil is provided, and a first metal material is laid on the fifth target screen printing stencil of the screen printing device. Furthermore, the screen printing squeegee of the screen printing device is held vertically against the mesh lines and scraped along the mesh line direction with a preset pressure. Through the hollow pattern area of ​​the fifth target screen printing stencil, it is accurately printed on the corresponding area of ​​the P-region sub-gate of the silicon substrate 110 to form the pattern corresponding to the P-region sub-gate, and then dried and sintered to produce the P-region sub-gate.

[0128] In addition, the printing order of sub-gates in P area and N area can be either printing sub-gates in P area first and then printing sub-gates, without restriction.

[0129] It should be noted that when the P-area sub-gates and N-area sub-gates are printed in steps, the P-area sub-gates and N-area sub-gates can be dried first, and then sintered together at high temperature.

[0130] S602. The printed third pattern is sintered to obtain the sub-gate 130.

[0131] As one possible implementation, a sintering apparatus can be provided to place the silicon substrate 110 with the printed third pattern into the sintering apparatus and sinter it based on a preset temperature profile to obtain the sub-gate 130.

[0132] The preset temperature curve can be found in the description above, and will not be repeated here.

[0133] As another possible implementation, a drying device and a sintering device can be provided. The silicon substrate 110 with the printed third pattern is placed in the drying device for drying, and after drying, the silicon substrate 110 with the printed third pattern is placed in the sintering device for sintering based on a preset temperature curve to obtain the sub-gate 130.

[0134] This pre-drying process prevents the slurry from "boiling" and splashing, ensuring the integrity of the third pattern.

[0135] As another possible implementation, in the case of printing the sub-gates in the P area and the N area in stages, if the printing time of the sub-gate is earlier than that of the sub-gate in the P area, the pattern corresponding to the sub-gate can be dried first, then the pattern corresponding to the sub-gate in the P area can be printed, and the pattern corresponding to the sub-gate in the P area can be dried. Finally, they are sintered together at high temperature to obtain the sub-gate 130.

[0136] As another possible implementation, in the case of printing the sub-gates in the P region and the N region in steps, if the printing time of the sub-gate in the P region is earlier than the printing time of the sub-gate, the pattern corresponding to the sub-gate in the P region can be dried first, then the pattern corresponding to the sub-gate can be printed, and the pattern corresponding to the sub-gate can be dried again. Finally, they are sintered together at high temperature to obtain the sub-gate 130.

[0137] This allows the organic solvents in the paste to evaporate, ensuring the conductivity of the paste after sintering, preventing the paste from being rubbed off during subsequent printing, and also increasing the richness of the manufacturing process.

[0138] In some embodiments, such as Figure 6 As shown, in order to provide a general overview of the fabrication method of the solar cell 100, this application also includes:

[0139] S701. Print the first pattern corresponding to the cascade structure on the P-type doped region and N-type doped region of the silicon substrate 110.

[0140] The specific implementation process of this step can be found in S301, and will not be elaborated here.

[0141] S702. Dry the printed first graphic to obtain a serialized structure.

[0142] The specific implementation process of this step can be found in S302, and will not be elaborated here.

[0143] S703. Using a second metal material, a third pattern is printed on the N-type doped region of the silicon substrate 110 and then dried to obtain the N-region sub-gate.

[0144] The specific implementation process of this step can be found in S501, and will not be elaborated here.

[0145] S704. Using a second metal material, print the corresponding third pattern on the P-type doped region of the silicon substrate 110, and then dry and sinter it to obtain the P-region sub-gate.

[0146] The specific implementation process of this step can be found in S501, and will not be elaborated here.

[0147] S705, the second pattern corresponding to the interconnect lines printed on the P-type doped region and N-type doped region of the silicon substrate 110.

[0148] The specific implementation process of this step can be found in S401, and will not be elaborated here.

[0149] S706. Sinter the printed second graphic to obtain the connecting line.

[0150] The specific implementation process of this step can be found in S402, and will not be elaborated here.

[0151] It is understood that in such an embodiment, the photovoltaic module corresponding to the solar cell 100 may further 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 100, the photovoltaic glass, adjacent cells, etc. As a filler, it can be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film can be an EVA film or a POE film, and the specific choice can be made according to the actual situation, without limitation.

[0152] Photovoltaic glass can be applied to the encapsulating film on the front of solar cells. This photovoltaic glass can be ultra-clear glass, possessing 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.

[0153] 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.

[0154] The photovoltaic system of this application embodiment includes the photovoltaic module described above.

[0155] 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.

[0156] 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.

[0157] 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 solar cell, characterized in that, include: Silicon substrate; The main gate, disposed on the silicon substrate, includes several series structures and connecting lines, wherein the connecting lines are disposed between two adjacent series structures; The material used to prepare the cascaded structure includes a first metallic material, and the material used to prepare the connecting wire includes a second metallic material.

2. The solar cell according to claim 1, characterized in that, The first metallic material is silver.

3. The solar cell according to claim 1, characterized in that, The second metallic material is a base metal.

4. The solar cell according to claim 3, characterized in that, The base metal is one or more of copper and aluminum.

5. A method for preparing a solar cell, characterized in that, include: Provide silicon substrate; A serial structure is fabricated on the silicon substrate using a first metallic material; A connecting wire is fabricated on the silicon substrate using a second metallic material, and the connecting wire is disposed between two adjacent serial structures.

6. The method according to claim 5, characterized in that, The first metallic material is silver.

7. The method according to claim 5, characterized in that, The second metallic material is a base metal.

8. The method according to claim 7, characterized in that, The base metal is one or more of copper and aluminum.

9. The method according to claim 5, characterized in that, The fabrication of the serial connection structure on the silicon substrate using a first metallic material includes: The first pattern corresponding to the serial structure is printed on the silicon substrate using the first metal material; The printed first pattern is sintered to obtain the serial connection structure.

10. The method according to claim 5, characterized in that, The fabrication of interconnects on the silicon substrate using a second metallic material includes: The second metal material is used to print a second pattern corresponding to the connecting line on the silicon substrate; The printed second pattern is sintered to obtain the connecting line.

11. The method according to claim 5, characterized in that, Prior to the step of fabricating interconnects on the silicon substrate using a second metallic material, the method further includes: A sub-gate is fabricated on the silicon substrate using the first metallic material.

12. The method according to claim 11, characterized in that, The process of fabricating a sub-gate on the silicon substrate using the first metallic material includes: The third pattern corresponding to the sub-gate is printed on the silicon substrate using the first metal material; The printed third pattern is sintered to obtain the sub-gate.

13. The method according to claim 10, characterized in that, The sintering temperature of the series structure is greater than that of the connecting wire.

14. A solar cell, characterized in that, The solar cell is made by the preparation method according to any one of claims 5-13.

15. A photovoltaic module, characterized in that, The photovoltaic module includes a solar cell as described in any one of claims 1-4 or claim 14.

16. A photovoltaic system, characterized in that, The photovoltaic system includes the photovoltaic module as described in claim 15.

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