Method for manufacturing a solar power generation module and solar power generation module

Abstract

This invention relates to a method for manufacturing solar power generation modules and to solar power generation modules themselves. [Solution] The manufacturing method includes the steps of: printing a grid line paste onto a solar cell semi-finished product and sintering it to form a grid line precursor; applying a laser-induced contact treatment to form a metal grid line and penetrating the metal grid line through the passivation layer to bring it into direct contact with the semiconductor layer; forming a plurality of conductive reinforcement microstructures at the contact interface between the metal grid line and the semiconductor layer, with the aggregate position of the conductive reinforcement microstructures corresponding to a specified region of the texture structure; overlapping and connecting an electrical connection member on the metal grid line and applying pressure to generate a conductive contact region between the electrical connection member and the metal grid line; applying an adhesive to the conductive contact region; and performing the crimping step and adhesive fixing step of the electrical connection member at a temperature of 180°C or lower, and a lamination step.

Description

Technical Field

[0001] This application relates to the field of solar cells, and particularly to photovoltaic power generation modules and methods for manufacturing the same.

Background Art

[0002] In the process of manufacturing a solar cell, after performing laser-induced contact treatment on the solar cell, the performance such as the photoelectric conversion efficiency of the solar cell can be significantly improved. However, when the solar cell subjected to laser-induced contact treatment is further assembled into a photovoltaic power generation module, indicators such as the photoelectric conversion efficiency are significantly reduced instead, and it is difficult to maintain the originally improved performance superiority of the solar cell.

Summary of the Invention

Problems to be Solved by the Invention

[0003] To solve the above technical problems, this application discloses a photovoltaic power generation module and a method for manufacturing the same, which can still maintain the improved electrical performance such as photoelectric conversion efficiency after the solar cell is subjected to laser-induced contact treatment when the solar cell is assembled into the photovoltaic power generation module.

Means for Solving the Problems

[0004] In a first aspect, an embodiment of this application provides a method for manufacturing a photovoltaic power generation module, the manufacturing method comprising: A printing and pre-sintering step of printing and sintering a grid line paste on a semi-finished solar cell including a substrate having a pyramidal texture structure on the surface and a semiconductor layer and a passivation layer provided in sequence on the substrate to form a grid line precursor; A solar cell manufacturing step comprising: subjecting the grid line precursor to laser-induced contact treatment to form a metal grid line; penetrating the metal grid line through the passivation layer and bringing it into direct contact with the semiconductor layer to manufacture a solar cell; further forming a plurality of conductive reinforcement microstructures at the contact interface between the metal grid line and the semiconductor layer; and the aggregate position of the conductive reinforcement microstructures corresponds to a region on the surface of the semiconductor layer where the distance from the vertex of the pyramidal texture structure is 1 μm or less, centered on the vertex of the pyramidal texture structure, which is a designated region of the pyramidal texture structure. A crimping step for an electrical connection member, comprising: overlapping the electrical connection member on the metal grid line and connecting them; applying pressure to the electrical connection member so that the electrical connection member and the metal grid line form a conductive contact area; A bonding and fixing step comprising applying an adhesive to the conductive contact area and connecting the plurality of solar cells to each other to form a battery string, A laminating step, comprising the step of stacking and laminating the battery strings and then manufacturing the photovoltaic module, The crimping step and the adhesive fixing step of the electrical connection member are both performed at a predetermined temperature, which is 180°C or lower, and in the solar cell of the battery string, the aggregate position of the conductive reinforcement microstructure corresponds to the designated region.

[0005] Furthermore, the metal grid line includes a main grid and a sub-grid arranged perpendicular to each other, and a pad, the pad being provided at at least one of the main grid, the sub-grid, and the intersection of the main grid and the sub-grid, the line width of the sub-grid being 15 μm to 25 μm, the area of ​​the pad being 0.04 mm × 0.04 mm to 1.1 mm × 1.1 mm, and in the crimping step of the electrical connection member, pressure is applied at the position where the electrical connection member and the pad intersect to cause the electrical connection member and the pad to form the conductive contact area. Alternatively, the metal grid line is a grid line without a main grid, and the crimping step of the electrical connection member is a step of overlapping and connecting the electrical connection member in a direction perpendicular to the metal grid line so that the electrical connection member and the metal grid line form an intersection, and applying pressure to the position of the electrical connection member corresponding to the intersection so that the conductive contact area is formed at the position of the intersection.

[0006] Furthermore, in the crimping step of the electrical connection member, the time for applying pressure to the electrical connection member is 10s to 30s, and / or the magnitude of the pressure applied to the electrical connection member is 3N to 5N.

[0007] Furthermore, in the lamination step, the lamination temperature is 150°C to 200°C.

[0008] Furthermore, the electrical connection member is a tin-bismuth alloy solder tape with a welding temperature of 150°C to 180°C.

[0009] Furthermore, the predetermined temperature is room temperature, and / or The adhesive is a conductive adhesive.

[0010] Furthermore, the substrate is a silicon substrate and / or, The semiconductor layer is a crystalline silicon semiconductor layer doped with a conductive element, and / or The passivation layer comprises one or more layers selected from an aluminum oxide layer, a silicon nitride layer, a silicon oxynitride layer, or a silicon oxide layer, and / or The grid line paste is a silver paste, and the aluminum content in the grid line paste is 1 wt% or less, and / or The aforementioned conductivity-enhancing microstructure includes a metallic dendrite conductor.

[0011] Furthermore, in the manufacturing step of the solar cell, the conditions for the laser-induced contact treatment include applying a reverse bias voltage of 9V to 15V in the process of providing the laser conditions, and the laser conditions are a single-wavelength spectrum with a wavelength of 500nm to 1200nm and a current density of 1000A / cm². 2 ~1400A / cm 2 This includes a scanning speed of 35 m / s to 55 m / s.

[0012] Furthermore, the solar cell includes a back-contact solar cell or a passivation contact solar cell.

[0013] In a second embodiment, the embodiment of the present application provides a photovoltaic power generation module, which is manufactured by the manufacturing method described in the first embodiment.

[0014] Furthermore, the solar power generation module is The aforementioned battery string, An adhesive film layer that seals the battery string from the outside, The adhesive film layer includes a translucent cover plate and a back plate provided on opposing surfaces of the adhesive film layer that are away from the battery string. [Effects of the Invention]

[0015] Compared to conventional technology, this application has at least the following beneficial effects. Specifically, this application manufactures a solar cell manufactured by laser-induced contact treatment, then presses and adhesively fixes an electrical connection member to it under low temperature conditions, and subsequently laminates the resulting battery string to manufacture a photovoltaic module. This reduces the impact on solar cell performance during the battery string manufacturing process, ensures that the conductive reinforcement microstructure formed by laser-induced contact treatment can still exhibit excellent conductive performance in the battery string, and further maintains the improvement in battery performance from the solar cell side to the photovoltaic module side, thus avoiding the problem of the originally improved battery performance being significantly reduced on the photovoltaic module side. To more clearly explain the embodiments of the present invention or the technical solutions according to the prior art, the drawings necessary for describing the embodiments or the prior art will be briefly described. The drawings described below are only shown in the embodiments of the present invention, and it is obvious that those skilled in the art can obtain the drawings of other embodiments based on these drawings without creative efforts.

Brief Description of Drawings

[0016] [Figure 1] It is a schematic diagram of the structure of a solar cell semi-finished product in an embodiment of the present application (only the structure of the light-receiving surface). [Figure 2] It is a schematic diagram of the structure of a solar cell in an embodiment of the present application (only the structure of the light-receiving surface). [Figure 3] It is a schematic diagram of a designated area in an embodiment of the present application. [Figure 4] It is a schematic diagram of the connection between a solar cell and an electrical connection member in an embodiment of the present application.

Modes for Carrying Out the Invention

[0017] To more clearly explain the technical solutions according to the embodiments of the present invention, the drawings necessary for describing the embodiments will be briefly described. The drawings described below are only shown in some embodiments of the present invention, and do not limit the scope of the claims. Those skilled in the art can also obtain other embodiments that belong to the protection scope of the present application based on the embodiments of the present application without creative efforts.

[0018] In the present application, the orientation or positional relationship indicated by terms such as "up", "down", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better explain the present application and its embodiments, and do not limit that the indicated device, element or component has a specific orientation or performs the structure and operation in a specific orientation.

[0019] Furthermore, some of the above terms may be used to express meanings other than those related to direction or position. For example, the term "above" may, in some cases, be used to express a dependency or connection. Those skilled in the art will be able to understand the specific meaning of these terms in this application depending on the specific context.

[0020] The terms “attached,” “installed,” “provided,” “connected,” and “linked” should be understood in a broad sense. For example, they may be fixed connections, removable connections, or integral structures; they may be mechanical or electrical connections; they may be direct connections or indirect connections via an intervening medium; and they may be internal communication between two devices, elements, or components. Those skilled in the art will be able to understand the specific meaning of these terms in this application depending on the specific circumstances.

[0021] Terms such as "first," "second," etc., are primarily used to distinguish between different devices, elements, or components (whether of the same or different types and structures), and are not intended to explicitly or implicitly indicate the relative importance or number of the devices, elements, or components shown. Unless otherwise specified, the term "multiple" means at least two.

[0022] In a first embodiment, the embodiments of this application provide a method for manufacturing a photovoltaic module, and the manufacturing method is A printing and pre-sintering step, as shown in Figure 1, involves printing a grid line paste onto a solar cell semi-product 1 which includes a substrate 100 having a pyramidal texture structure 101 on its surface, and a semiconductor layer 200 and a passivation layer 300 arranged sequentially on the substrate 100, and sintering it to form a grid line precursor. A solar cell manufacturing step comprising: applying a laser-induced contact treatment to a grid line precursor to form a metal grid line; penetrating the metal grid line through a passivation layer 300 to directly contact the semiconductor layer 200 to manufacture a solar cell; further, as shown in Figures 2 and 3, a plurality of conductive reinforcement microstructures 500 are formed at the contact interface between the metal grid line 400 and the semiconductor layer 200; and the aggregate position of the conductive reinforcement microstructures 500 corresponds to a region on the surface of the semiconductor layer 200 where the distance from the vertex of the pyramidal texture structure 101 is 1 μm or less, centered on the vertex of the pyramidal texture structure 101, which is a designated region 101a of the pyramidal texture structure 101; A crimping step for electrical connection members, as shown in Figure 4, involves overlapping and connecting the electrical connection member 3 on the metal grid line 400, and applying pressure to the electrical connection member 3 to create a conductive contact area between the electrical connection member 3 and the metal grid line 400. The bonding and fixing step involves applying adhesive to the conductive contact area, connecting multiple solar cells 2 to each other to form a battery string, and both the crimping step and the bonding and fixing step of the electrical connection member are performed at a predetermined temperature, which is 180°C or lower, and in the solar cells 2 of the battery string, the assembly position of the conductive reinforcement microstructure 500 corresponds to the step of the designated area 101a. A lamination step, comprising the step of stacking and laminating battery strings, and then manufacturing a photovoltaic module.

[0023] This application provides a photovoltaic power generation module and a method for manufacturing the same. By manufacturing a photovoltaic power generation module by pressing and adhesively fixing an electrical connection member 3 to a solar cell 2 manufactured by laser-induced contact treatment under low temperature conditions, and then laminating it, it is ensured that the conductive reinforcement microstructure 500 formed by the laser-induced contact treatment can still exhibit excellent conductive performance in the solar cell 2. Furthermore, the effect of improving battery performance can be maintained from the solar cell side to the photovoltaic power generation module side, and the problem of the originally improved battery performance being significantly reduced on the photovoltaic power generation module side is avoided.

[0024] First, in the process of manufacturing the solar cell 2, a conductive reinforcement microstructure 500 is formed at the contact interface between the semiconductor layer 200 and the metal grid line 400 of the solar cell 2 by laser-induced contact treatment. This conductive reinforcement microstructure 500 mainly concentrates at the vertices and nearby regions corresponding to the pyramidal texture structure 101, and has the advantage of reducing the contact resistance between the semiconductor layer 200 and the metal grid line 400, thereby improving contact performance.

[0025] Next, this application found the following: Taking the manufacture of a TOPCon solar cell as an example, after performing laser-induced contact treatment on the light-receiving surface of solar cell 2, the minority carrier recombination loss decreased significantly, the open-circuit voltage increased by 8mV to 10mV, and the photoelectric conversion efficiency of solar cell 2 also improved by 0.2% to 0.5%. However, after manufacturing solar cell 2, which already had such improved performance, into a photovoltaic module, the photoelectric conversion efficiency of the photovoltaic module decreased significantly, demonstrating no performance advantage from technical improvements on the solar cell 2 side. Through research, the applicant discovered that the main cause of the above technical problem is that the fill factor decreases significantly during the process of welding solar cell 2 to the battery string, and further causes a loss of photoelectric conversion efficiency from the solar cell side to the photovoltaic module side.

[0026] Further research reveals that after laser-induced contact treatment, the solar cell 2 has conductive reinforcement microstructures 500 formed mainly at the contact interface between the semiconductor layer 200 and the metal grid lines 400. Furthermore, these conductive reinforcement microstructures 500 are concentrated in the vicinity of the vertices corresponding to the pyramidal texture structure 101. This structure and its distribution are advantageous for improving carrier transport capacity and for reducing contact resistance between the semiconductor layer 200 and the metal grid lines 400. However, excessively high welding process temperatures (usually exceeding 200°C) during the welding process of the solar cell 2 to the battery string destroy the conductive reinforcement microstructures 500, dispersing the multiple conductive reinforcement microstructures 500 that were originally concentrated in the vicinity of the vertices of the pyramidal texture surface, worsening contact between the semiconductor layer 200 and the metal grid lines 400, and affecting the fill factor of the solar cell 2.

[0027] To solve the above problem, the embodiment of this application, based on the premise that the performance of the solar cell 2 is improved by utilizing a laser-induced contact processing process, first places the electrical connection member 3 on the metal grid line 400 at a predetermined temperature of 180°C or less and applies pressure, then performs adhesive fixing, and the electrical connection member 3 is brought into direct contact with the metal grid line 400 by the pressure to form a conductive contact area, and then fixes the conductive contact area using an adhesive. Because the temperature of the operation in which pressure is applied and adhesive fixing is performed is relatively low, after adhesive fixing, the reinforced conductive structure in the solar cell 2 is not destroyed and still gathers in the area near the apex of the pyramidal texture structure 101, and therefore, in this process, the improved fill factor, photoelectric conversion efficiency, and other performance of the solar cell 2 do not suffer from the problem of performance being significantly reduced by the operation in which the battery string is formed.

[0028] Finally, after the battery string is manufactured and the performance of the solar cell 2 is maintained, the embodiment of this application performs lamination and stacking operations on the battery string, and the lamination further strengthens the electrical connection between the electrical connection member 3 and the metal grid line 400, ensuring good structural and electrical connection stability between the electrical connection member 3 and the metal grid line 400.

[0029] The designated region 101a is a region where the conductive reinforcement microstructures 500 are concentrated near the vertices of the pyramidal texture structure 101 on the surface of the semiconductor layer 200. As shown in Figure 3, the conductive reinforcement microstructures 500 are mainly concentrated near the vertices of the pyramidal texture structure 101, and the range of this vicinity region is a range with a radius R of 1 μm or less, with the vertices of the pyramids on the surface of the semiconductor layer 200 as the center.

[0030] The requirement that the specified temperature be 180°C or lower includes any value under those temperature conditions. For example, the specified temperature may be 180°C, 150°C, 120°C, 100°C, 80°C, 50°C, 45°C, 40°C, 35°C, 30°C, 25°C, 20°C, or 15°C. The specified temperature used in the crimping step of the electrical connection member may be the same as or different from the specified temperature used in the adhesive fixing step. For example, the crimping operation of the electrical connection member may be performed at 50°C, and the adhesive fixing operation may be performed at 160°C, or both the crimping operation and the adhesive fixing operation may be performed at 160°C.

[0031] Preferably, the specified temperature is room temperature. In this application, room temperature refers to an ambient temperature of 15°C to 25°C. Performing crimping and adhesive fixing of electrical connection members under room temperature conditions replaces welding, avoids damage to the conductive reinforced microstructure caused by welding, is advantageous in better maintaining the benefits of concentrated distribution in the vicinity of the apex of the pyramidal texture structure 101 of the conductive reinforced microstructure 500 on the solar power generation module side, and ensures that improvements in performance such as fill factor and photoelectric conversion efficiency are not significantly reduced by being manufactured in the battery string.

[0032] The adhesive is a conductive adhesive. If the adhesive includes a conductive adhesive, the conductive adhesive may include, for example, a conductive polymer adhesive (e.g., an adhesive made of polypyrrole or polyaniline), a conductive glass adhesive, and the like.

[0033] The following describes each of the important steps in the above manufacturing method.

[0034] In the crimping step of the electrical connection member, different crimping methods can be used depending on the type of metal grid line 400.

[0035] In one embodiment, as shown in Figure 4, Figure 4 shows a schematic diagram of the connection between the solar cell 2 and the electrical connection member 3 from a plan view of the light-receiving surface of the solar cell 2. For the sake of explanation, some of the electrical connection members 3 on the metal grid lines 400 are not shown. The metal grid lines 400 include a main grid 401 and a sub-grid 402, which are arranged perpendicular to each other, and a pad 403. The pad 403 is located on the main grid 401. The line width of the sub-grid 402 is 15 μm to 25 μm, and the area of ​​the pad 403 is 0.04 mm × 0.04 mm to 1.1 mm × 1.1 mm. To make it clear, the pad 403 may be located at at least one of the following positions: the main grid 401, the sub-grid 402, and the intersection of the main grid 401 and the sub-grid 402. For example, the pad 403 may be located on the sub-grid 402, or the pad 403 may be located at the intersection of the main grid 401 and the sub-grid 402. This application is not limited thereto.

[0036] In the crimping step of the electrical connection member, the metal grid line 400 applies pressure to the position where the electrical connection member 3 and the pad 403 intersect, thereby forming a conductive contact area between the electrical connection member 3 and the pad 403.

[0037] Because the pad 403 has a large surface area and a larger contact area than the sub-grid 402, when pressure is applied at the intersection of the electrical connection member 3 and the pad 403 to form a conductive contact area, the large surface area of ​​the pad 403 means that the requirements for alignment accuracy are relatively low, which helps to simplify the production process and reduces contact failures due to alignment problems. Furthermore, the large surface area of ​​the pad 403 means that a larger metal area is in contact with the electrical connection member 3, which is advantageous not only for providing good electrical connection performance but also for cooperative operation with subsequent lamination steps, strengthening the mechanical bond strength between the metal grid line 400 and the electrical connection member 3 and helping to improve the durability of the photovoltaic module.

[0038] In another embodiment, the metal grid line is a grid line without a main grid. That is, all metal grid lines are narrow grids with a narrow line width. For this type of metal grid line, the crimping step of the electrical connection member involves overlapping and connecting the electrical connection member in a direction perpendicular to the metal grid line to form an intersection between the electrical connection member and the metal grid line, applying pressure to the position of the electrical connection member corresponding to the intersection, and forming a conductive contact area at the position of the intersection.

[0039] Furthermore, in the crimping step of the electrical connection member, the time for which pressure is applied to the electrical connection member 3 is 10s to 30s, and the magnitude of the applied pressure is 3N to 5N. By controlling the time and magnitude of pressure application within this range, direct contact between the electrical connection member 3 and the metal grid line 400 can be promoted, ensuring the crimping effect, and damage to the metal grid line 400 and the conductive reinforced microstructure 500 can be avoided.

[0040] In the lamination step, the lamination temperature is 150°C to 200°C. Furthermore, a lead-free tin-bismuth alloy solder tape with a melting temperature of 150°C to 180°C is used as the electrical connection member 3. In the embodiments of this application, relatively low lamination temperature conditions are employed, and simultaneously, a lead-free tin-bismuth alloy solder tape with a relatively low melting point is used as the electrical connection member 3. This allows the alloy in the electrical connection member 3 to melt during the lamination process, resulting in better connection with the metal grid line 400. Furthermore, it works in conjunction with the adhesive layer to improve the reliability of the structural and electrical connection between the electrical connection member 3 and the metal grid line 400.

[0041] In the lamination step, lamination of the battery string involves first arranging the battery string, adhesive film layer, translucent cover plate, back plate, etc., in a specific order, and then performing a lamination operation on these layer structures to form a photovoltaic module. For example, the lamination may involve arranging these structures in the order of translucent cover plate, adhesive film layer, battery string, adhesive film layer, and back plate. Then, heating is performed using a laminator to melt the adhesive film layer and bond each layer, and the layers are tightly bonded by the pressure of the laminator. There may be other options for the lamination order and material layers, for example, adding a transparent conductive film, a reflective film, etc., and this application is not limited thereto. As the adhesive film layer, a material film layer with a melting point less than 200°C, such as EVA adhesive film, POE adhesive film, PVB adhesive film, etc., can be selected, and this application is not limited thereto.

[0042] Furthermore, the use of a lead-free tin-bismuth alloy solder tape with a welding temperature of 150°C to 180°C as the electrical connection member 3 means that the welding strip includes an internal base material (e.g., a copper core wire) and a solder layer applied to the surface of the base material, and that the solder layer is made of lead-free tin-bismuth alloy solder with a welding temperature of 150°C to 180°C. In the selectable configuration, the mass percentage of tin in the lead-free tin-bismuth alloy solder is 42%, the mass percentage of bismuth is 57.6%, and the remainder is an auxiliary material, such as a metallic element such as silver, copper, or antimony, and this application is not limited thereto. For example, a low-temperature lead-free tin-bismuth alloy solder composed of 0.4 wt% Ag, 42 wt% Sn, and 57.6 wt% Bi is used, and its melting point is approximately 138°C.

[0043] As described above, in the process of welding the solar cells 2 together to form a battery string after laser-induced contact treatment, the conductive reinforced microstructure 500 is destroyed and moves from a state of being aggregated in the designated region 101a to a state of being dispersed, thereby reducing battery performance and preventing the achievement of the desired efficiency improvement effect. This problem is further exacerbated in the lamination step; that is, if the lamination operation is performed after the conductive reinforced microstructure 500 has been destroyed and dispersed, the degree of destruction tends to become more severe. In contrast, conventional solar cells 2 that have not undergone laser-induced contact treatment do not have the problem of significantly reduced contact performance between the semiconductor layer 200 and the metal grid line 400 after being welded to the battery string, and furthermore, they do not have the problem of more pronounced performance degradation after lamination.

[0044] In this application, since the process for manufacturing the battery string employs compression and adhesive fixing under low-temperature conditions, the conductive reinforced microstructure 500 does not suffer serious damage and still mainly concentrates in the vicinity of the vertices of the pyramidal texture structure 101. Therefore, after lamination, a low lamination temperature for a battery string with such structural features only promotes further fusion between the electrical connection member 3 and the metal grid line 400, without destroying the conductive reinforced microstructure 500, and ultimately the benefit of improved battery performance appears from the battery side to the photovoltaic module side without significant degradation.

[0045] In the embodiments of this application, the solar cell semi-finished product 1 includes a substrate 100 having a pyramidal texture structure 101 on its surface, and a semiconductor layer 200 and a passivation layer 300 arranged sequentially on the substrate 100. The solar cell 2 further includes metal grid lines 400 that penetrate the passivation layer 300 and are in direct contact with the semiconductor layer 200.

[0046] The substrate 100 is a silicon substrate 100. The silicon substrate 100 can have a pyramidal texture structure 101 formed on its surface by a texturing process.

[0047] The semiconductor layer 200 is a crystalline silicon semiconductor layer 200 doped with a conductive element. The conductive element may be an N-type conductive element (e.g., phosphorus) or a P-type conductive element (e.g., boron). The semiconductor layer 200 may be a diffuse silicon layer formed by thermally diffusing a conductive element into the substrate 100 for doping, or it may be a crystalline silicon layer formed by doping the substrate 100 with a doping element using a deposition method (e.g., LPCVD deposition method or PECVD deposition method). Since the semiconductor layer 200 is formed on the substrate 100 by the above method, the semiconductor layer 200 has a pyramidal texture structure 101 that matches the shape of the substrate 100. It is preferable that the semiconductor layer 200 be provided on the light-receiving surface of the substrate 100.

[0048] The passivation layer 300 is provided on the side of the semiconductor layer 200 that is away from the substrate 100. The passivation layer 300 includes one or more layers selected from an aluminum oxide layer, a silicon nitride layer, a silicon oxynitride layer, or a silicon oxide layer. Exemplarily, the passivation layer 300 includes a first passivation layer 300 provided in close proximity to the semiconductor layer 200 and a second passivation layer 300 provided away from the semiconductor layer 200. The first passivation layer 300 employs an aluminum oxide layer and primarily performs a passivation function, while the second passivation layer 300 employs a composite film layer of a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer and performs both a passivation function and an anti-reflective function. As another example, the second passivation layer 300 may consist of only a single film layer, and this application is not limited thereto.

[0049] Furthermore, the grid line paste used to manufacture the metal grid line 400 is a silver paste, and the aluminum content in the grid line paste is 1 wt% or less.

[0050] Furthermore, the conductive-enhanced microstructure 500 includes a metallic dendrite conductor. The conductive-enhanced microstructure 500 is a conductive structure formed at the contact interface between the metallic grid line 400 and the semiconductor layer 200 after laser-induced contact treatment. For example, if the semiconductor layer 200 is a crystalline silicon semiconductor layer 200 doped with a conductive element, the grid line paste is a silver paste, and the metallic grid line 400 is a silver grid line, the conductive-enhanced microstructure 500 includes a silver dendrite conductor grown at the contact interface, and this silver dendrite conductor is a crystalline body formed by the melting and subsequent recrystallization of metallic silver particles in the silver paste. In related technologies, carrier transport between the semiconductor layer 200 and the metallic grid line 400 generally depends solely on metallic silver particles, but in this application, the silver dendrite conductor has a stronger carrier transport capacity than metallic silver particles, thus enhancing the contact performance between the metallic grid line 400 and the semiconductor layer 200 and reducing contact resistance.

[0051] Furthermore, the metallic dendrite conductor includes a crystalline main chain and crystalline side chains extending from the crystalline main chain in a different growth direction from the crystalline main chain. As a result, the entire metallic dendrite conductor exhibits a divergent dendrite shape, increasing the contact area between the semiconductor layer 200 and the metallic grid line 400.

[0052] The following describes the steps for manufacturing solar cell 2.

[0053] In the process of performing laser-induced contact treatment on the grid line precursor, a reverse bias voltage is applied. This reverse bias voltage is used to further strengthen the built-in electric field of the solar cell 2 at the contact interface between the semiconductor layer 200 and the grid line precursor, while the laser-induced contact treatment conditions generate a large amount of photogenerated carriers (i.e., electron-hole pairs). Through the combined action of these two points, electron carriers and hole carriers are rapidly transported to the semiconductor layer 200 by the selective action of the electric field, and carriers with the electrical properties of one type of charge are rapidly transported by the acceleration action of the electric field. If the surface of the semiconductor layer 200 has a pyramidal texture structure 101, carriers are easily transported at the vertices and vicinity of the vertices of the pyramidal texture structure 101.

[0054] The vertices and vicinity of the vertices of the pyramidal texture structure 101 become designated regions 101a where subsequent conductive reinforcement microstructures 500 are gathered. Specifically, after the laser-induced contact processing conditions are released, the temperature of the contact region between the metal grid line 400 and the semiconductor layer 200 decreases, and metal atoms continuously precipitate from the common crystal composed of metal and semiconductor elements to form a conductive cocrystal (for example, if the metal grid line 400 is a silver grid line and the semiconductor layer 200 is a crystalline silicon semiconductor layer 200 doped with conductive elements, the conductive cocrystal is a cocrystal formed of silver and silicon elements), and conductive reinforcement microstructures 500 (e.g., silver dendrite conductors) are grown using the conductive cocrystal as nucleation sites.

[0055] Preferably, the conditions for the laser-induced contact treatment include applying a reverse bias voltage of 9V to 15V in the process of providing the laser conditions, and the laser conditions are a single-wavelength spectrum with a wavelength of 500nm to 1200nm and a current density of 1000A / cm². 2 ~1400A / cm 2 This includes a scanning speed of 35 m / s to 55 m / s.

[0056] As an alternative, the solar cell in the embodiment of this application may be a back-contact solar cell or a passivation contact solar cell.

[0057] In a second embodiment, the present application provides a photovoltaic module which is manufactured by the manufacturing method described in the first embodiment.

[0058] Furthermore, the solar power generation module is Battery string and An adhesive film layer that seals the battery string from the outside, It includes a translucent cover plate and a back plate provided on opposing surfaces of the adhesive film layer that are away from the battery string.

[0059] The present application will be further described below with reference to more specific examples. The grid line paste, welding strips, etc., used in the following examples can all be commercially purchased and obtained. For example, commercially available DK-93T type silver grid line paste is used as the grid line paste, with an Al content of 0.05 wt% to 0.10 wt% and an oxygen content of 1.0 wt% to 5.0 wt%. The elemental content in the silver grid line paste can be measured using a spectrometer (EDS, Energy Dispersive Spectrometer).

[0060] Example 1 This embodiment provides a 72-type photovoltaic power generation module, and its manufacturing method is as follows: In the printing and pre-sintering step, a grid line paste is printed onto a solar cell semi-finished product and sintered to form a grid line precursor. The solar cell semi-finished product includes a silicon substrate having a pyramidal texture structure on its surface, and a boron-doped crystalline silicon layer, an aluminum oxide passivation layer, and a silicon oxynitride passivation anti-reflective layer arranged sequentially on the light-receiving surface of the silicon substrate. The sintering temperature is 730°C to 750°C. In the manufacturing steps of the solar cell, a laser-induced contact treatment is applied to the grid line precursor to form a metal grid line, and the metal grid line is then passed through the silicon oxynitride passivation anti-reflective layer and the aluminum oxide passivation layer before being brought into direct contact with the boron-doped crystalline silicon layer. At the contact interface, a conductive-enhancing microstructure is formed, which is aggregated in a designated region of a pyramidal texture structure. The designated region is centered on the vertex of the pyramidal texture structure on the surface of the boron-doped crystalline silicon layer, and is a region with a distance of 1 μm or less from the vertex. The metal grid line is a silver grid line and includes a main grid and a sub-grid that are perpendicular to each other, and a pad provided on the main grid. The line width of the sub-grid is 20 μm, and the area of ​​the pad is 0.96 mm². 2 The reverse bias voltage is 15V, the laser conditions are a laser wavelength of 1064nm, and a current density of 1200A / cm². 2 This includes a scanning speed of 40 m / s, In the crimping step of the electrical connection member, the electrical connection member is overlapped and connected on the metal grid line, and pressure is applied at the position where the electrical connection member and the pad intersect. The magnitude of the pressure is 4N, and the pressure is applied for 20 seconds, thereby creating a conductive contact area between the electrical connection member and the pad on the metal grid line. The electrical connection member is a lead-free tin-bismuth alloy solder tape with a welding temperature of 150°C to 180°C. In the adhesive fixing step, a conductive adhesive is applied to the conductive contact area, and multiple solar cells are connected to form a battery string. Both the crimping step and the adhesive fixing step of the electrical connection members are performed at a predetermined temperature of 180°C. In the lamination step, the battery strings are stacked and laminated to manufacture the solar power generation module. The lamination temperature is 150°C to 200°C.

[0061] Examples 2 to 3 The main difference between Example 1 and Examples 2 and 3 lies in the predetermined temperature, as shown in Table 1.

[0062] Comparative Examples 1 to 3 The main difference between Comparative Examples 1 to 3 and Example 1 lies in the predetermined temperature, as shown in Table 1.

[0063] Furthermore, Comparative Examples 1 to 3 do not employ crimping and adhesive fixing of the electrical connection members, but instead directly high-temperature welding the electrical connection members and metal grid lines at a predetermined temperature, and the welding strips used are copper strips coated with tin, and the components of the coating layer contain 63 wt% Sn and 37% Pb.

[0064] Explanation of performance tests In the contact resistivity test, the TLM (Transmission Line Method) will be used.

[0065] In photoelectric conversion testing, the fill factor (IV) test obtains a complete IV curve by precisely controlling the voltage applied to the solar cell and measuring the corresponding current value. During the test process, the test machine gradually changes the voltage value, decreasing it from the open-circuit voltage (i.e., the voltage when the solar cell is not connected to a load) to the voltage value corresponding to the short-circuit current (i.e., the current when the solar cell is short-circuited). At each voltage point, the test machine records the corresponding current value, ultimately drawing a complete IV curve. FF = ImVm / IscVoc, and the fill factor (FF) is calculated by dividing the rectangular area formed by the IV curve at the maximum power point by the area formed by Voc and Isc. The photoelectric conversion test is performed at an irradiation intensity of 1000 M / cm². 2Therefore, if the operating temperature of the solar cell is 25°C ± 2°C, the maximum output power is divided by the solar irradiance, multiplied by the light absorption area of ​​the solar cell, and then multiplied by 100%.

[0066] In power testing of photovoltaic modules, the test method involves exposing the photovoltaic module to a known light source environment and measuring the current and voltage to calculate the module's output power. The specific steps include first selecting a standard light source of known intensity, irradiating the module's surface with this light, then measuring the module's output current, connecting a voltmeter to record the reading at the module's output terminal, obtaining the output voltage value, and determining that the power can be obtained based on the product of the current and voltage.

[0067] [Table 1]

[0068] As can be seen from the test results in Table 1, Comparative Examples 1 to 3 construct battery strings by directly high-temperature welding solar cells at a high predetermined temperature after laser-induced contact treatment. As can be seen by comparing the performance indicators of the solar cells before and after assembly, the fill factor of the solar cells decreased significantly after high-temperature welding, and the photoelectric conversion efficiency was lost in large quantities. This indicates that the conductive reinforced microstructure formed after laser-induced contact treatment is affected after high-temperature welding, and the originally improved battery performance cannot be maintained on the solar power generation module side. In the solar cells according to Examples 1 to 3 of this application, when assembled into a battery string, the loss of both fill factor and photoelectric conversion efficiency decreased. In particular, the solar cell according to Example 3 did not decrease in fill factor and photoelectric conversion efficiency before and after assembly, which is advantageous in maintaining the performance improvement benefits that laser-induced contact treatment brings to solar cells.

[0069] The above has provided a detailed explanation of the technical solutions disclosed in the embodiments of this application, and this specification has used specific examples to illustrate the principles and embodiments of this application. However, the above description of embodiments is intended to help understand the technical solutions and core inventive features of the embodiments of this application. At the same time, those skilled in the art can modify the specific embodiments and scope of application based on the concept of this application, and therefore, the contents of this specification should not be understood as limiting this application. [Explanation of Symbols]

[0070] 1 Solar cell semi-finished products 2 Solar cells 3. Electrical connection components 100 circuit boards 101 Pyramid-shaped texture structure 101a Specified area 200 semiconductor layers 300 Passivation Layers 400 Metal Grid Lines 401 Main Grid 402 Subgrid 403 Pad 500 Conductivity-enhancing microstructure.

Claims

1. A method for manufacturing a solar power generation module, The aforementioned manufacturing method is A printing and pre-sintering step comprising printing a grid line paste onto a solar cell semi-finished product, which includes a substrate having a pyramidal texture structure on its surface and a semiconductor layer and a passivation layer provided sequentially on the substrate, and sintering it to form a grid line precursor, A solar cell manufacturing step comprising: subjecting the grid line precursor to laser-induced contact treatment to form a metal grid line; penetrating the metal grid line through the passivation layer and bringing it into direct contact with the semiconductor layer to manufacture a solar cell; further forming a plurality of conductive reinforcement microstructures at the contact interface between the metal grid line and the semiconductor layer; and the aggregate position of the conductive reinforcement microstructures corresponds to a region on the surface of the semiconductor layer where the distance from the vertex of the pyramidal texture structure is 1 μm or less, centered on the vertex of the pyramidal texture structure, which is a designated region of the pyramidal texture structure. A crimping step for an electrical connection member, comprising: overlapping the electrical connection member on the metal grid line and connecting them; applying pressure to the electrical connection member so that the electrical connection member and the metal grid line form a conductive contact area; A bonding and fixing step comprising applying an adhesive to the conductive contact area and connecting the plurality of solar cells to each other to form a battery string, A laminating step, comprising the step of stacking and laminating the battery strings and then manufacturing the photovoltaic module, A manufacturing method characterized in that both the crimping step and the adhesive fixing step of the electrical connection member are performed at a predetermined temperature, the predetermined temperature being 180°C or lower, and the assembly position of the conductive reinforcement microstructure in the solar cell of the battery string corresponds to the designated region.

2. The metal grid line includes a main grid and a sub-grid arranged perpendicular to each other, and a pad, the pad being provided at at least one of the main grid, the sub-grid, and the intersection of the main grid and the sub-grid, the line width of the sub-grid being 15 μm to 25 μm, the area of ​​the pad being 0.04 mm × 0.04 mm to 1.1 mm × 1.1 mm, and in the crimping step of the electrical connection member, pressure is applied at the position where the electrical connection member and the pad intersect to form the conductive contact area between the electrical connection member and the pad. Alternatively, the manufacturing method according to claim 1, wherein the metal grid line is a grid line without a main grid, and the crimping step of the electrical connection member is a step of overlapping and connecting the electrical connection member in a direction perpendicular to the metal grid line so that the electrical connection member and the metal grid line form an intersection, and applying pressure to the position of the electrical connection member corresponding to the intersection so that the conductive contact area is formed at the position of the intersection.

3. In the crimping step of the electrical connection member, The time for applying pressure to the electrical connection member is 10s to 30s, and / or The manufacturing method according to claim 1, characterized in that the magnitude of the pressure applied to the electrical connection member is 3N to 5N.

4. The manufacturing method according to claim 1, characterized in that the lamination temperature in the lamination step is 150°C to 200°C.

5. The manufacturing method according to claim 1, characterized in that the electrical connection member is a tin-bismuth alloy solder tape having a welding temperature of 150°C to 180°C.

6. The aforementioned predetermined temperature is room temperature, and / or, The manufacturing method according to claim 1, characterized in that the adhesive is a conductive adhesive.

7. The substrate is a silicon substrate, and / or, The semiconductor layer is a crystalline silicon semiconductor layer doped with a conductive element, and / or The passivation layer comprises one or more layers selected from an aluminum oxide layer, a silicon nitride layer, a silicon oxynitride layer, or a silicon oxide layer, and / or The grid line paste is a silver paste, and the aluminum content in the grid line paste is 1 wt% or less, and / or The manufacturing method according to any one of claims 1 to 6, characterized in that the conductivity-enhancing microstructure includes a metallic dendrite conductor.

8. In the manufacturing step of the solar cell, the conditions for the laser-induced contact treatment include applying a reverse bias voltage of 9V to 15V in the process of providing the laser conditions, and the laser conditions are a single-wavelength spectrum with a wavelength of 500nm to 1200nm and a current density of 1000A / cm². ２ ~1400 A / cm ２ The manufacturing method according to any one of claims 1 to 6, characterized in that the scanning speed is 35 m / s to 55 m / s.

9. The manufacturing method according to any one of claims 1 to 6, characterized in that the solar cell includes a back-contact solar cell or a passivation contact solar cell.

10. It is a solar power generation module, The solar power generation module is characterized in that it is manufactured by the manufacturing method described in any one of claims 1 to 9.

11. The aforementioned solar power generation module is The aforementioned battery string, An adhesive film layer that seals the battery string from the outside, The photovoltaic module according to claim 10, further comprising a translucent cover plate and a back plate provided on opposing surfaces of the adhesive film layer that are away from the battery string.

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