Solder strip obtaining method and solar cell welding method

Abstract

The invention relates to a welding strip obtaining method and a welding method of a solar cell piece. The welding strip obtaining method comprises the following steps that effective welding parameters of a welding device are obtained; obtaining effective geometric parameters of the solder strip; based on the effective welding parameters and the effective geometric parameters, the yield strength range matched with the welding strip is obtained; and based on the yield strength range, a welding strip matched with the welding device is selected. According to the solder strip obtaining method and the welding method of the solar cell, the pseudo soldering rate of the solder strip is remarkably reduced, the solder strip is prevented from plastic deformation, cross section area reduction or snap due to overlarge wire winding tension, and the resistance of the solder strip is prevented from being increased, so that the welding quality and the electrical performance are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic modules, in particular to a welding strip obtaining method and a solar cell welding method. BACKGROUND

[0002] The welding quality of a photovoltaic module is directly related to the power generation efficiency and long-term reliability of the module. In the existing module manufacturing process, the drum-type welding is gradually replacing the traditional flat-type welding method due to its high bonding precision, high production efficiency, and compact device structure. The working process of drum-type welding usually relies on the bonding of the welding strip to the arc surface of the drum under the action of the winding tension. At the same time, the welding strip will undergo tensile deformation and bending deformation during the bonding process, which puts higher and more precise requirements on the mechanical properties of the welding strip.

[0003] However, the selection of the welding strip in the prior art mainly focuses on its electrical conductivity and tensile strength, and the matching relationship between the yield strength of the welding strip and the drum welding structure is not paid enough attention to. When the yield strength of the welding strip does not match the welding device parameters (such as drum radius, winding tension, etc.), a series of welding defects are easily caused. For example, when the yield strength is too high, the bending stiffness of the welding strip is large, and it is difficult to fully bond with the head and tail regions of the cell busbar, which increases the risk of false welding. At the same time, the plastic deformation capacity of the high yield strength welding strip is insufficient during the heat cycle, which easily causes stress concentration of the welding point and leads to large warping or even rupture of the cell. When the yield strength is too low, the welding strip is prone to plastic deformation under the action of the winding tension, which causes the cross-sectional area to decrease and the resistance to increase, and in severe cases, the welding strip may even break, thereby reducing the electrical performance and reliability of the photovoltaic module.

[0004] At present, there is still a lack of clear standards to quantitatively relate the yield strength of the welding strip to the core welding device parameters such as drum radius and winding tension, and there is also no systematic welding strip selection and welding method that can be directly used to guide production.

[0005] Therefore, there is an urgent need for a welding strip obtaining method and a welding method that can accurately match the yield strength of the welding strip according to the welding device parameters to solve the technical problems of false welding, cell warping, and poor module reliability in drum-type welding. SUMMARY

[0006] Based on this, it is necessary to provide a welding strip obtaining method and a solar cell welding method to solve the problems of false welding and breakage, and low welding reliability in the drum welding of the prior art.

[0007] To achieve the above-mentioned purpose, on the one hand, the present application provides a welding strip obtaining method, comprising the following steps:

[0008] obtaining the effective welding parameters of the welding device;

[0009] Obtain the effective geometric parameters of the solder strip;

[0010] Based on the effective welding parameters and the effective geometric parameters, the yield strength range suitable for the weld strip is obtained;

[0011] Based on the yield strength range, the welding strip that is compatible with the welding device is selected.

[0012] In one embodiment, the welding apparatus includes a curved welding component, and the effective welding parameters include the radius of curvature of the curved welding component.

[0013] In one embodiment, obtaining the effective geometric parameters of the solder strip includes:

[0014] Obtain the cross-sectional shape and cross-sectional dimension parameters of the welding strip.

[0015] In one embodiment, obtaining the yield strength range of the weld strip based on the effective welding parameters and the effective geometric parameters includes:

[0016] A mechanical analysis model is constructed based on the effective welding parameters and the effective geometric parameters to obtain the initial yield strength range;

[0017] Based on the initial yield strength range, welding verification is performed on the weld strips with different yield strengths to obtain the yield strength range.

[0018] In one embodiment, the step of constructing a mechanical analysis model based on the effective welding parameters and the effective geometric parameters to obtain the initial yield strength range includes:

[0019] Based on the effective geometric parameters, the cross-sectional moment of inertia of the weld strip is obtained;

[0020] The bending stiffness of the weld strip is obtained based on the moment of inertia of the cross section.

[0021] Based on the bending stiffness and the effective welding parameters, the bending stress when the welding strip is attached to the welding device is obtained;

[0022] The initial yield strength range is determined based on the bending stress.

[0023] In one embodiment, the initial yield strength range is not less than the bending stress, and the yield strength range is 40MPa~80MPa.

[0024] This application also provides a method for welding solar cells, comprising the following steps:

[0025] A solar cell is provided, the solar cell including grid lines;

[0026] Provides solder strips obtained based on the solder strip acquisition method described in any of the above embodiments;

[0027] The solder strip is soldered to the grid line.

[0028] In one embodiment, welding the solder strip to the gate line includes:

[0029] Provide welding equipment;

[0030] The solar cell is fixed to the welding device;

[0031] Make the solder strip adhere to the grid line;

[0032] The bonded solder strip is then welded to the grid line.

[0033] In one embodiment, the welding apparatus includes a curved welding component and an adsorption mechanism, the adsorption mechanism being located on the curved welding component, and fixing the solar cell to the welding apparatus includes:

[0034] The adsorption mechanism is used to adsorb the solar cell to fix it onto the curved welding component.

[0035] In one embodiment, the welding apparatus further includes a curing mechanism and a thermal welding mechanism, wherein welding the bonded solder strip to the grid line includes:

[0036] The curing mechanism is used to cure the solder strip and the grid lines;

[0037] The hot welding mechanism is used to hot weld the welding strip to the grid line.

[0038] The aforementioned method for obtaining solder strips and welding solar cells acquires the effective welding parameters of the welding device and the effective geometric parameters of the solder strip. Based on these parameters, it determines the suitable yield strength range for the solder strip, thereby obtaining solder strips compatible with the welding device. This achieves quantitative matching of the solder strip's yield strength, providing a clear calculation basis for solder strip selection. Furthermore, by determining the solder strip's yield strength, the rate of incomplete soldering at the beginning and end can be significantly reduced, preventing the solder strip from undergoing plastic deformation, reducing its cross-sectional area, or breaking due to excessive wire tension, thus preventing an increase in solder strip resistance and improving welding quality and electrical performance. In addition, the solder strip acquisition method of this application is applicable to solder strips of different specifications and different welding devices, exhibiting strong versatility and effectively improving the stability of the welding process and the consistency and reliability of photovoltaic modules. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a flowchart of a solder strip acquisition method provided in one embodiment;

[0041] Figure 2 This is a schematic diagram of the welding apparatus in a welding strip acquisition method provided in one embodiment;

[0042] Figure 3 This is a schematic diagram of the structure of the curved surface welding component in a welding strip acquisition method provided in one embodiment;

[0043] Figure 4 This is a flowchart of a welding method for solar cells provided in one embodiment;

[0044] Figure 5 This is a schematic diagram of a solar cell welding method provided in one embodiment, in which a thermal welding mechanism is used to thermally weld the solder strip to the grid lines.

[0045] Explanation of reference numerals in the attached figures:

[0046] 1-Welding device, 11-Curved surface welding component, 12-Wire laying mechanism, 13-Thermal welding mechanism, 2-Welding strip, 3-Solar cell, 31-Grid line. Detailed Implementation

[0047] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0049] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, regions, layers, doping types, and / or portions, these elements, components, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, doping type, or portion from another element, component, region, layer, doping type, or portion. Therefore, without departing from the teachings of this invention, the first element, component, region, layer, doping type, or portion discussed below may be referred to as a second element, component, region, layer, or portion.

[0050] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0051] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, in this specification, the term “and / or” includes any and all combinations of the associated listed items.

[0052] Please see Figure 1 This application provides a method for obtaining solder strip, comprising the following steps:

[0053] Step S1: Obtain the effective welding parameters of welding device 1;

[0054] Step S2: Obtain the effective geometric parameters of solder strip 2;

[0055] Step S3: Based on the effective welding parameters and effective geometric parameters, obtain the yield strength range suitable for weld strip 2;

[0056] Step S4: Select a welding strip 2 that is compatible with the welding device 1 based on the yield strength range.

[0057] In the above example, by obtaining the effective welding parameters of welding device 1 and the effective geometric parameters of welding strip 2, and calculating the suitable yield strength range of welding strip 2 based on both, a welding strip 2 compatible with welding device 1 is obtained, achieving quantitative matching of welding strip yield strength and providing a clear calculation basis for welding strip selection. Furthermore, by determining the yield strength of welding strip 2, the rate of false welds at the beginning and end can be significantly reduced, preventing the welding strip 2 from undergoing plastic deformation, reducing its cross-sectional area, or breaking due to excessive wire tension, thus preventing an increase in the resistance of welding strip 2 and improving welding quality and electrical performance. In addition, the above method for obtaining welding strips is applicable to welding strips 2 of different specifications and welding devices 1 of different structures, exhibiting strong versatility and effectively improving the stability of the welding process and the consistency and reliability of photovoltaic modules.

[0058] Specifically, please refer to Figures 2-3 Execute step S1 to obtain the effective welding parameters of welding device 1.

[0059] In one embodiment, such as Figure 2 and Figure 3 As shown, the welding apparatus 1 includes a curved welding component 11, such as a roller welding component, wherein the curved welding component 11 is used to support the solar cell 3 and provide the welding strip 2 around the curved reference surface. Obtaining the effective welding parameters of the welding apparatus 1 includes:

[0060] Obtain the radius R of the curved surface of the welded component 11. The radius R is the effective working radius of the welded component 11, which is the actual bending radius when the welding strip 2 is wrapped around it. This parameter is usually calibrated at the factory when the welding device 1 leaves the factory, and can be checked in the equipment technical manual or confirmed by actual measurement using a diameter gauge. It will not be described in detail here.

[0061] Furthermore, the curvature of the curved welding component 11 directly affects the degree of bending of the welding strip 2. The smaller the radius of curvature, the greater the curvature of the welding strip 2, and the greater the bending deformation and bending stress; conversely, the larger the radius of curvature, the smaller the bending stress. Therefore, the radius of curvature is a key basic parameter for deriving the suitable range of the yield strength of the welding strip 2. In this embodiment, the radius of curvature is 0.19m.

[0062] In one embodiment, such as Figure 2 and Figure 3As shown, the welding apparatus 1 also includes a wire feeding mechanism 12, which is used to apply a stable wire tension to the welding strip 2 to achieve uniform feeding of the welding strip 2, and further ensure that the welding strip 2 is neither slack nor overstretched during the winding process, thereby obtaining effective welding parameters of the welding apparatus 1. It also includes:

[0063] The wire tension F applied by the cable tray structure to the solder strip 2 is obtained. The magnitude of the wire tension directly affects the plastic deformation of the solder strip 2 during the bonding process. When the yield strength of the solder strip 2 is low, the wire tension needs to be controlled to avoid plastic deformation; when the yield strength is high, the tension can be appropriately increased to ensure a tight bond between the solder strip 2 and the cable. The optimal value of the wire tension needs to be determined comprehensively based on the equipment, solder strip performance, and test welding results, and is not limited thereto. In this embodiment, the solder strip 2 is subjected to a wire tension of 3–5 N during welding to ensure stable cable routing.

[0064] Specifically, step S2 is performed to obtain the effective geometric parameters of the solder strip 2.

[0065] In one embodiment, obtaining the effective geometric parameters of the solder strip 2 includes:

[0066] Obtain the cross-sectional shape and dimensions of the welding strip 2. Here, the cross-section refers to the section of the welding strip 2 perpendicular to its length. Its shape and dimensions directly determine the moment of inertia and bending stiffness of the welding strip 2, thus affecting the magnitude of the bending stress experienced by the welding strip 2 when it is bonded to the curved surface of the roller. Under the condition of a constant surface radius, material elastic modulus, and wire tension, different cross-sectional parameters will lead to differences in bending stress, thereby affecting the bonding effect and welding quality of the welding strip 2 and the grid lines 31 of the solar cell 3.

[0067] In one embodiment, the cross-sectional shape includes a rectangle or an irregular shape. Here, the irregular shape specifically refers to an unconventional cross-sectional shape that differs from the conventional rectangular welding strip. Specifically, it includes, but is not limited to, circles, triangles, and trapezoids. Other cross-sectional shapes that are suitable for curved surface welding scenarios and can meet the requirements of welding strength and bonding accuracy can also be adopted.

[0068] Furthermore, different cross-sectional shapes of the welding strip 2 correspond to different cross-sectional dimension parameters. For example, when the welding strip 2 has a rectangular cross-section, the cross-sectional parameters include the width B, which is in meters and represents the dimension along the axial direction of the roller-type curved surface welding component 11, and the thickness H, which is in meters and represents the dimension perpendicular to the roller axis.

[0069] When the weld strip 2 has a circular cross-section, the cross-sectional parameters include the diameter d, which is in meters.

[0070] When the weld strip 2 has a triangular cross-section, the cross-sectional parameters include the base width b, which is in meters, representing the length of the base of the triangle, and the height h, which is in meters, representing the vertical distance from the base to the opposite side.

[0071] For weld strips 2 with other cross-sectional shapes, the cross-sectional dimensions can be the equivalent dimensions of that shape. For example, when weld strip 2 has a trapezoidal cross-section, its dimensions can include the width of the upper base, the width of the lower base, and the height.

[0072] The cross-sectional shape and size parameters mentioned above can be used to calculate the cross-sectional moment of inertia, bending stiffness, and resulting bending stress of the weld strip 2, providing basic data for determining the suitable yield strength range of the weld strip 2.

[0073] Specifically, step S3 is performed to obtain the yield strength range suitable for the weld strip 2 based on the effective welding parameters and effective geometric parameters.

[0074] In one embodiment, obtaining the yield strength range suitable for the weld strip 2 based on effective welding parameters and effective size parameters includes:

[0075] Based on the cross-sectional parameters, the moment of inertia of the weld strip 2 is obtained; where the moment of inertia is a geometric parameter that measures the ability of the weld strip cross-section to resist bending deformation, and its value is only related to the cross-sectional shape and size, and is not related to the material properties.

[0076] Specifically, weld strips 2 with different cross-sectional shapes have different formulas for calculating the moment of inertia due to differences in geometry. In this embodiment, the cross-sectional shape of weld strip 2 is rectangular, and its formula for calculating the moment of inertia is as follows: Where B is the width of the welding strip 2 and H is the thickness of the welding strip 2. If it is a welding strip of other shapes, it shall be calculated according to the standard formula of the moment of inertia of the corresponding shape, which will not be elaborated here.

[0077] Based on the moment of inertia of the cross section, the bending stiffness of the welding strip 2 is obtained. Bending stiffness is a core mechanical parameter characterizing the welding strip 2's ability to resist bending deformation. The larger the bending stiffness D, the more difficult it is for the welding strip to undergo bending deformation, and the more likely it is to have a loose bond with the solar cell. The formula for calculating the bending stiffness is as follows: D is the bending stiffness of the welding strip 2 (in N·m²); E is the elastic modulus of the material of the welding strip 2 (in MPa). In this embodiment, ;

[0078] Based on bending stiffness and effective welding parameters, the bending stress when the welding strip 2 is attached to the welding device 1 is obtained. When the welding strip 2 is attached to the arc-shaped surface of the curved welding component 11, bending deformation occurs due to the surface constraint, resulting in bending stress. The magnitude of the bending stress is directly related to the bending stiffness and the radius of curvature of the curved surface. When the welding strip 2 is attached to the curved surface, the radius of curvature of the bending of the welding strip 2 should meet the following requirements. Then the bending moment of weld strip 2 at this time is Under these conditions, the bending stress of weld strip 2 is Where y is the distance from the neutral axis of the weld strip cross section. When the cross-sectional shape of weld strip 2 is rectangular, the neutral axis of the cross section is located at the midpoint of the thickness direction, i.e. Then the corresponding bending stress at this time is It should be noted that the mechanical analysis model refers to the model constructed above, which calculates the stress and deformation state of the weld strip 2 by inputting effective geometric parameters and effective welding parameters, thereby deriving a suitable yield strength range.

[0079] For example, when the cross-sectional parameters of the welding strip 2 are 0.26*0.15mm, combined with the effective welding parameters of surface radius R=0.19m, wire tension of 3-5N, and elastic modulus of welding strip 2 of 25223MPa, the moment of inertia of the cross section (rectangular welding strip) is determined through a mechanical analysis model. Bending moment Bending stress The theoretical lower limit of the yield strength of the welding strip 2 is derived to be 9.96 MPa, ensuring that only elastic deformation occurs when the welding strip 2 is bonded, thus avoiding bonding failure.

[0080] Based on bending stress, the initial yield strength range is determined, and the initial yield strength range is not less than the bending stress. Specifically, to ensure that the welding strip 2 only undergoes elastic deformation during the bonding process and avoids bonding failure due to plastic deformation, which could lead to incomplete soldering, the yield strength of the welding strip 2 must not be less than the bending stress, i.e., the initial yield strength range is... , where σ y Yield strength;

[0081] Based on the initial yield strength range, welding verification was performed on weld strips with different yield strengths to obtain the yield strength range. For example, the yield strength range is 40MPa~80MPa.

[0082] Specifically, the initial yield strength range only considers the theoretical constraints of bending deformation and needs to be verified and optimized in combination with actual welding scenarios to cover actual influencing factors such as wire tension, ambient temperature, and material fluctuations. Therefore, in order to verify the optimal yield strength, this application also conducted welding verification.

[0083] Table 1

[0084]

[0085] In one embodiment, as shown in Table 1, a comparative test table of performance parameters and head-end cold welds for different specifications of welding strips 2 is presented (where maximum force refers to the maximum tensile force that welding strip 2 can withstand when it breaks in a tensile test; elongation at break also corresponds to the length change rate of welding strip 2 when it breaks in a tensile test, both of which are verification indicators of the mechanical properties of welding strip 2). Referring to Table 1, the core correlation between the yield strength of welding strip 2 and head-end cold welds can be clearly defined. Experimental results show that welding strips 2 with high yield strength are prone to cold welds. For example, the effective geometric parameters of the first group of welding strips 2 are 0.16×0.07mm, the yield strength is 207.88MPa, and approximately 5mm of head-end cold welds are produced during use; the effective geometric parameters of the second group of welding strips 2 are 0.26×0.15mm, the yield strength is 137.63MPa, and approximately 20mm of head-end cold welds are produced during use. The elastic moduli of these two sets of welding strips 2 are 103823.34MPa and 97615.38MPa, respectively. The materials are relatively rigid and difficult to fit tightly with the grid lines 31 of the solar cell 3.

[0086] In contrast, the weld strips 2 with medium and low yield strength showed good bonding and no incomplete welds were observed: the effective geometric parameters of the weld strips 2 in the third group were 0.26×0.12mm and the yield strength was 75.88MPa; the effective geometric parameters of the weld strips 2 in the fourth group were 0.26×0.15mm and the yield strength was 65.68MPa. The yield strengths of the weld strips 2 in both groups were close to 70MPa and lower than 80MPa, and no incomplete welds were observed after welding.

[0087] Furthermore, this application also verifies that when the yield strength of the welding strip 2 is less than 40 MPa, the welding strip 2 is prone to plastic deformation under the action of wire tension, resulting in thinning or breakage. At the same time, the reduction in cross-sectional area will lead to a decrease in electrical conductivity.

[0088] In summary, this application determines that the yield strength of the weld strip must be greater than 40 MPa to avoid premature yielding and fracture, while being less than 80 MPa to ensure the flexibility of the weld strip 2 and adapt to the curvature of the roller-type curved surface welding component 11. Preferably, the yield strength range is 40~70 MPa. Within this range, the weld strip 2 exhibits extremely low incomplete weld rate, optimal bonding uniformity and stability, and can simultaneously meet the dual requirements of resisting incomplete welds and resisting deformation and fracture.

[0089] It is worth noting that the wire tension of the second, third, and fourth groups of welding strip 2 in the experiment was 5N (only the first group was 1.8N), which eliminated the interference of wire tension on the cold weld. Combined with the positive correlation between elastic modulus and yield strength, it further confirms that yield strength is the core factor affecting the cold weld.

[0090] Specifically, the yield strength of the solder strip 2 is determined by the material. In this embodiment, the solder strip 2 is composed of a copper substrate and a surface coating. The copper substrate is oxygen-free copper with a purity of ≥99.97%, which dominates the conductivity. The surface coating is a tin alloy, which is used to enhance weldability and corrosion resistance.

[0091] The above-described method for obtaining the welding strip first uses a mechanical analysis model to quantitatively analyze the bending behavior of the welding strip 2 during the bonding process with the curved welding component 11, and calculates the theoretical lower limit of the yield strength using the bending stress formula. Then, combined with actual welding experiments, the bonding effect and incomplete welding conditions of the welding strip 2 with different yield strengths are verified, ultimately determining the yield strength range of the welding strip 2 suitable for this process. The formula calculation and experimental verification corroborate each other, making the conclusions repeatable and industrially applicable.

[0092] Please see Figure 4 In one embodiment, this application also provides a method for welding solar cells, comprising the following steps:

[0093] Step S100: Provide a solar cell 3, the solar cell 3 including grid lines 31;

[0094] Step S200: Provide solder strip 2 obtained based on the solder strip acquisition method as described in any of the above embodiments;

[0095] Step S300: Solder the solder strip 2 to the grid line 31.

[0096] Specifically, please refer to Figure 5 Steps S100 to S300 are performed to provide a solar cell 3, which includes grid lines 31, and to provide a solder strip 2 obtained based on the solder strip acquisition method described in any of the above embodiments; the solder strip 2 is then soldered to the grid lines 31.

[0097] In one embodiment, soldering the solder strip 2 to the gate line 31 includes:

[0098] Welding apparatus 1 is provided;

[0099] Fix the solar cell 3 onto the welding device 1;

[0100] Make the solder strip 2 adhere to the grid line 31;

[0101] The bonded solder strip 2 is then soldered to the grid line 31.

[0102] In one embodiment, the welding apparatus 1 includes a curved welding component 11 and an adsorption mechanism (not shown). The adsorption mechanism is located on the curved welding component 11 and fixes the solar cell 3 to the welding apparatus 1, including:

[0103] An adsorption mechanism is used to adsorb the solar cell 3 and fix it onto the curved welding component 11.

[0104] The curved welding component 11 has an arc-shaped bonding structure that allows the welding strip 2 to form a line contact with the grid lines 31 of the solar cell 3. Compared with the surface contact mode of traditional flat welding, the bonding pressure is more concentrated, which is conducive to the full metallization welding reaction.

[0105] In one embodiment, the welding apparatus 1 further includes a robotic arm (not shown), which, before securing the solar cell 3 to the welding apparatus 1, also includes:

[0106] A robotic arm is used to grasp the solar cell 3 and place it on the curved welding component 11. The solar cell 3 is placed on the curved welding component 11 at a certain angle to ensure that the direction of the grid line 31 of the solar cell 3 is parallel to the axis of the curved welding component 11.

[0107] In one embodiment, the welding apparatus 1 further includes a wire laying mechanism 12 for attaching the solder strip 2 to the grid wire 31, including:

[0108] One end of the welding strip 2 is fixed to the starting point of the winding of the curved surface welding component 11;

[0109] The welding strip 2 is fed at a constant speed by the wiring mechanism 12, and the curved welding component 11 rotates at a constant speed to make the welding strip 2 adhere to the grid line 31.

[0110] The process includes feeding the solder strip 2 at a constant speed via the wiring mechanism 12, and coordinating with the uniform rotation of the curved welding component 11 to ensure the solder strip 2 adheres to the grid line 31.

[0111] The welding ribbon 2 covers the grid lines 31 of the solar cell 3 along the cylindrical spiral trajectory under the cooperative motion, and the wire laying mechanism 12 monitors the winding tension in real time to ensure stable bonding pressure.

[0112] After the welding strip 2 covers all the grid lines 31, the wiring mechanism 12 stops feeding, the curved welding component 11 rotates to the end position, and the welding strip 2 is cut by the shearing mechanism. The cut surface is perpendicular to the grid lines 31 to avoid the fitting gap caused by the oblique cut.

[0113] The wire winding mechanism 12 applies stable wire tension to the welding strip 2 to achieve uniform feeding of the welding strip 2 and further ensures that the welding strip 2 neither loosens nor becomes overstretched during the winding process. Simultaneously, the rotation of the roller and the synchronous feeding of the wire winding mechanism 12 enable continuous winding of the welding strip 2, significantly improving welding efficiency. Furthermore, this structure eliminates the need for additional space for placing the welding strip 2, resulting in higher overall equipment integration and adaptability for mass production of large-size solar cells 3.

[0114] In one embodiment, the welding apparatus 1 further includes a curing mechanism (not shown) and a thermal welding mechanism 13, which welds the bonded solder strip 2 to the grid line 31, including:

[0115] A curing mechanism is used to cure the solder strip 2 and the grid line 31;

[0116] The curing mechanism is used to cure the solder strip 2 and the grid line 31, including:

[0117] Along the length of the solder strip 2, apply photosensitive curing adhesive to the surface of the bonded solder strip 2;

[0118] The solder ribbon 2 and the solar cell 3 roller are fed into the curing mechanism to cure the photosensitive curing adhesive. The curing mechanism includes an ultraviolet light box and the photosensitive curing adhesive includes an ultraviolet fixing adhesive. It can quickly cure the solder ribbon 2 after it is attached to the grid line 31, so that the solder ribbon 2 maintains a stable position during the subsequent hot welding process, preventing displacement or lifting, thereby ensuring welding accuracy and uniformity, improving welding yield and component consistency.

[0119] The welding strip 2 is thermally welded to the grid line 31 using a thermal welding mechanism 13.

[0120] Among them, such as Figure 5 As shown, the hot welding mechanism 13 is used to hot weld the solder strip 2 to the grid line 31, including:

[0121] The cured solar cell 3 is fed into the thermal welding mechanism 13, so that the contact area between the solder ribbon 2 and the grid line 31 is uniformly heated, thereby realizing the metallization welding of the solder ribbon 2 and the solar cell 3. The thermal welding mechanism 13 includes an infrared lamp box, which can uniformly heat the contact area between the cured solder ribbon 2 and the grid line 31, thereby realizing reliable metallization welding of the solder ribbon and the solar cell 3, ensuring that the temperature of the welding area is controllable, the welding quality is stable, and the welding yield and electrical performance are improved.

[0122] The aforementioned welding method for solar cells employs a solder strip acquisition method to select solder strips 2 that match the welding device 1. This ensures that the solder strips 2 undergo only elastic deformation without plastic deformation or breakage during the roller-type curved surface welding process, thereby significantly reducing the rate of incomplete welds at the beginning and end, and improving the uniformity and stability of the weld bonding. Simultaneously, through the cooperation of the curing mechanism and the thermal welding mechanism 13, the solder strips 2 and the grid lines 31 achieve a reliable metallized connection, further improving the welding yield, electrical performance, and the consistency and reliability of the photovoltaic module. This method is applicable to solder strips 2 of different sizes and welding devices with different curvatures, exhibiting strong versatility and industrial applicability.

[0123] It should be understood that, although Figure 1 , Figure 4 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 , Figure 4 At least some of the steps in the process may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but may be executed at different times. The execution order of these steps or stages is not necessarily sequential, but may be executed in turn or alternately with other steps or at least some of the steps or stages in other steps.

[0124] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0125] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0126] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for obtaining solder strip, characterized in that, Includes the following steps: Obtain the effective welding parameters of the welding equipment; Obtain the effective geometric parameters of the solder strip; Based on the effective welding parameters and the effective geometric parameters, the yield strength range suitable for the weld strip is obtained; Based on the yield strength range, the welding strip that is compatible with the welding device is selected.

2. The method for obtaining solder strip according to claim 1, characterized in that, The welding apparatus includes a curved surface welding component, and the effective welding parameters include the radius of curvature of the curved surface welding component.

3. The method for obtaining solder strip according to claim 1, characterized in that, The acquisition of effective geometric parameters of the solder strip includes: Obtain the cross-sectional shape and cross-sectional dimension parameters of the welding strip.

4. The method for obtaining solder strip according to claim 1, characterized in that, The step of obtaining the yield strength range suitable for the weld strip based on the effective welding parameters and the effective geometric parameters includes: A mechanical analysis model is constructed based on the effective welding parameters and the effective geometric parameters to obtain the initial yield strength range; Based on the initial yield strength range, welding verification is performed on the weld strips with different yield strengths to obtain the yield strength range.

5. The method for obtaining solder strip according to claim 4, characterized in that, The construction of a mechanical analysis model based on the effective welding parameters and the effective geometric parameters to obtain the initial yield strength range includes: Based on the effective geometric parameters, the cross-sectional moment of inertia of the weld strip is obtained; The bending stiffness of the weld strip is obtained based on the moment of inertia of the cross section. Based on the bending stiffness and the effective welding parameters, the bending stress when the welding strip is attached to the welding device is obtained. The initial yield strength range is determined based on the bending stress.

6. The method for obtaining solder strip according to claim 5, characterized in that, The initial yield strength range is not less than the bending stress, and the yield strength range is 40MPa~80MPa.

7. A method for welding solar cells, characterized in that, Includes the following steps: A solar cell is provided, the solar cell including grid lines; Provides solder strip obtained based on the solder strip acquisition method as described in any one of claims 1 to 6; The solder strip is soldered to the grid line.

8. The welding method according to claim 7, characterized in that, The step of welding the solder strip to the grid line includes: Provide welding equipment; The solar cell is fixed to the welding device; Make the solder strip adhere to the grid line; The bonded solder strip is then welded to the grid line.

9. The welding method according to claim 8, characterized in that, The welding device includes a curved surface welding component and an adsorption mechanism, wherein the adsorption mechanism is located on the curved surface welding component, and fixing the solar cell to the welding device includes: The adsorption mechanism is used to adsorb the solar cell to fix it onto the curved welding component.

10. The welding method according to claim 8, characterized in that, The welding apparatus further includes a curing mechanism and a thermal welding mechanism, wherein welding the bonded solder strip to the grid line includes: The curing mechanism is used to cure the solder strip and the grid line; The hot welding mechanism is used to hot weld the welding strip to the grid line.

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