Method for handling solder strips of photovoltaic modules and stringer

Abstract

The application discloses a kind of welding strip processing method and string welding machine, wherein the method includes: during the welding strip is pulled from supply side to welding side, the local section of welding strip is calendered at preset flattening position, the thickness of local section is reduced, and the width is increased, to form flat calendered section;The welding strip is pulled to preset cutting position and clamped, and the non-end position of flat calendered section is cut.This application reduces the height difference of the position where the busbar is located, reduces the probability of glass breakage or hidden crack;Realize the linkage with string welding machine pull strip process, under the premise of not changing the original string welding machine core process and not increasing production rhythm, complete the flattening and shaping of the lead-out end of the welding strip in battery string, realize the flattening and pull strip, cutting linkage, completely match with mass production rhythm, high production efficiency;The end of welding strip is flattened before string welding, and the vibration of flattening will not affect the electrical connection effect of electrical connection position, improve the stability and reliability of assembly.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic technology, specifically relating to a method for processing the solder strip of a photovoltaic module and a string welding machine. Background Technology

[0002] Individual solar photovoltaic (PV) cells have poor mechanical strength, are easily affected by the environment, and have limited output voltage, current, and power. Therefore, multiple cells are usually electrically connected by soldering strips to form a cell string, which is then encapsulated into a photovoltaic module. Glass, due to its good light transmission and mechanical properties, is a common panel material in photovoltaic modules.

[0003] In photovoltaic modules, busbars are electrically connected to solder strips to collect charge carriers gathered from the solar cells. However, the connection area between the busbars and solder strips has increased local thickness due to material stacking, which can easily lead to stress concentration during lamination, causing glass breakage or microcracks, thus affecting the reliability and lifespan of the module. Summary of the Invention

[0004] This application aims to provide a method for processing the solder strip of a photovoltaic module and a string welding machine to solve the problems of the prior art requiring additional steps when shaping the lead-out end of the solder strip, thus affecting the production cycle, and the easy occurrence of glass breakage or damage at the busbar position in photovoltaic modules.

[0005] In a first aspect, embodiments of this application propose a method for processing the solder strips of a photovoltaic module, comprising: Rolling step: During the process of pulling the welding strip from the feeding side to the welding side, a local section of the welding strip is rolled at a preset flattening position, so that the thickness of the local section is reduced and the width is increased to form a flat rolled section. First cutting step: Pull the welding strip to the preset cutting position and clamp it, and cut the non-end position of the flat rolled section so that the end of the welding strip retains a flat rolled section of a predetermined length as the welding part for leading out the busbar.

[0006] In this application, the solder strip is flattened during the pulling process from the feeding side to the welding side, and then cut to retain a flat rolled section of a predetermined length at the end of the solder strip. This flat rolled section extends beyond the battery string and is then welded to the busbar. Subsequently, the flat rolled section at the end of the solder strip is welded to the busbar, which has the following beneficial effects: First, the welding part of the solder strip that is welded to the busbar is a flattened rolled section, which reduces the height difference at the location of the busbar, reduces the probability of glass breakage or microcracks, and improves the lifespan of the photovoltaic module.

[0007] Secondly, this application flattens the welding strip during the pulling process from the feeding side to the welding side, that is, it achieves flattening in the strip pulling process of the string welding machine. The flattening of the welding strip is linked with the strip pulling process of the string welding machine. Without changing the original core process of the string welding machine or increasing the production cycle, the flattening and shaping of the lead end of the welding strip in the battery string is completed. The flattening, pulling and cutting are linked, which is fully matched with the mass production cycle, resulting in high production efficiency and easy mass production.

[0008] Third, this application flattens the ends of the solder strips before stringing, and the vibration caused by flattening will not affect the electrical connection effect of the battery string or the electrical connection position inside the module, thus improving the stability and reliability of the module.

[0009] Fourth, compared to the unflattened portion of the solder strip, the flat rolled section has a larger width. In photovoltaic modules, the flat rolled section is welded to the busbar. Therefore, it can increase the welding area between the solder strip and the busbar, improve the electrical connection effect, and increase the welding pull force. At the same time, the end position of the flat rolled section is the transition position between the beginning and end of the flattening. Compared to the middle position of the flattening, the width of this end position is relatively small. The cutting position is the non-end position of the flat rolled section, which can ensure that the width of the flat rolled section retained at the end of the solder strip is larger, which can further increase the welding area with the busbar, improve the electrical connection effect, and increase the welding pull force.

[0010] In some embodiments, the solder strips include: a first group of solder strips and a second group of solder strips; The rolling step includes: rolling a local section of each of the first group of weld strips, and / or rolling a local section of each of the second group of weld strips. After cutting: Along the extension direction of the battery string, the first group of solder strips is located at the head of the battery string, and the second group of solder strips is located at the tail of the battery string. Along a second direction intersecting the extension direction of the battery string, each solder strip in the first group of solder strips and each solder strip in the second group of solder strips are staggered.

[0011] In some embodiments, the number of battery cells in a battery string is m, where m is an odd number; The rolling step includes: rolling local sections of each of the first group of weld strips, and rolling local sections of each of the second group of weld strips. The method further includes a residual material removal step: at the beginning stage of the next round of strip pulling, the remaining flat rolled sections on the feeding side of the first group of welding strips and the second group of welding strips are pulled out to a first preset length, and the remaining flat rolled sections are cut off.

[0012] In some embodiments, the first group of solder strips and the second group of solder strips are rolled simultaneously; or, the first group of solder strips and the second group of solder strips are rolled sequentially.

[0013] In some embodiments, the number of battery cells in a battery string is m, where m is an even number; The rolling step includes: rolling local sections of each of the first group of weld strips; In the first cutting step, the flat rolled section is cut in the center along the extension direction of the battery string; The method further includes a second cutting step: pulling out the flat rolled section remaining on the feeding side corresponding to the first group of welding strips to a second preset length, and cutting it to obtain a third group of welding strips.

[0014] In some embodiments, in the extension direction of the solder strip, before cutting: the width of the flat rolled section first increases and then decreases, and / or, the thickness of the flat rolled section first decreases and then increases; and / or, Before cutting: The projected shape of the flat calendered section is at least one of the following: shuttle shape, rounded rectangle, and rounded-edge ellipse.

[0015] In some embodiments, the thickness reduction rate of the rolled section is 20% to 80%, and the width increase rate is 50% to 250%.

[0016] In some embodiments, the initial thickness of the portion of the solder strip outside the flat rolled section is 0.13 mm to 0.4 mm, and the initial width is 0.4 mm to 1.2 mm; the thickness of the flat rolled section is 0.05 mm to 0.15 mm, and the width is 0.8 mm to 2.2 mm; and / or, Before cutting, the length of the flat rolled section is 5mm to 12mm; the direction of this length is along the extension direction of the weld strip; and / or, The predetermined length is 3mm to 7mm.

[0017] In some embodiments, the method further includes: bending the welding strip so that the flat rolled section and the busbar welded thereto are disposed on the back side of the battery string.

[0018] In some embodiments, during the rolling step, a localized section of the solder strip is heated; and / or, Before the rolling step, the method further includes heating a local section of the solder strip.

[0019] Secondly, embodiments of this application propose a string welding machine, including: a pull handle, a flattening mechanism, and a cutting mechanism; The pull handle is used to pull the welding strip from the feeding side to the welding side; The flattening mechanism is located in the pulling path of the puller and is used to roll a local section of the welding strip to reduce the thickness and increase the width of the local section, forming a flat rolled section. The cutting structure is used to cut the non-end positions of the flat rolled section after the welding strip is pulled to the preset cutting position.

[0020] In some embodiments, the flattening mechanism includes: a support base; A support pad, fixed on the bearing base, has a weld strip bearing surface; The flattened pressure head is positioned opposite the support pad; A lifting drive unit is connected to the flattening head and is used to drive the flattening head to move towards or away from the support pad.

[0021] In some embodiments, the flattening head includes: a heating structure for heating a localized section of the solder strip during the rolling process; and / or, The lifting drive component includes one of: a cylinder, a servo electric cylinder, and a linear motor; and / or, The welding strip bearing surface is provided with multiple limiting grooves for positioning the welding strip and limiting its lateral displacement during the rolling process; and / or, The surface of the welding strip is flush with the surface of the welding strip conveyor along the pulling path of the string welding machine.

[0022] In some embodiments, the pull handle includes: two pull handles, one pull handle for pulling out a first group of welding strips, and the other pull handle for pulling out a second group of welding strips; or, the pull handle includes: one pull handle for sequentially pulling out the first group of welding strips and the second group of welding strips; and / or, The flattening mechanism includes: a first flattening mechanism and a second flattening mechanism, wherein the first flattening mechanism is used to roll the first group of welding strips and the second flattening mechanism is used to roll the second group of welding strips; or, the flattening mechanism includes: a flattening mechanism for sequentially rolling the first group of welding strips and the second group of welding strips.

[0023] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0024] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a flowchart of the steps of a photovoltaic module solder strip processing method according to an embodiment of this application; Figure 2 , Figure 4 and Figure 5 This is a partial structural schematic diagram of a string welding machine according to an embodiment of this application; Figure 3 This is a schematic diagram of the structure of the solder strip before the rolling step according to an embodiment of this application; Figure 6 and Figure 7 This is a schematic diagram of the cutting of the solder strip after the rolling step according to an embodiment of this application; Figure 8 This is a schematic diagram of the structure of the cut solder strip end being a flat rolled section according to an embodiment of this application; Figures 9 to 12 These are schematic diagrams of four battery string structures according to embodiments of this application; Figures 13 to 16 This is a schematic diagram of the structure of the flat rolled section of the solder strip before cutting according to four embodiments of this application.

[0025] Figure label: 1-Welding strip, 11-Flat rolled section, 12-Residual flat rolled section, 13-Cutting position, 200-String welding machine, 21-Pulling handle, 211-First gripper, 212-Second gripper, 221-First flattening mechanism, 222-Second flattening mechanism, 223-Bearing base, 224-Supporting pad, 225-Flattening pressure head, 226-Lifting drive component, 231-First cutting mechanism, 232-Second cutting mechanism, 2311-First cutter, 2312-First clamping strip, 2321-Second cutter, 2322-Second clamping strip, 24-Transmission mechanism, 300-Battery string, 3-Battery cell, 31-Electrical connection part, 4-Busbar. Detailed Implementation

[0026] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0027] The inventors of this application have discovered that the main reasons why glass breakage or damage easily occurs at the busbar location in existing photovoltaic modules are as follows: First, as the output voltage of the photovoltaic module increases, the potential difference between the busbar and the glass increases significantly. In high-temperature and high-humidity environments, alkali metal ions such as sodium ions in the glass are attracted by a strong electric field and migrate towards the vicinity of the busbar, undergoing electrochemical reactions and inducing material aging. Second, as the output voltage of the photovoltaic module increases, tiny bubbles or defects inside the module are more easily ionized and broken down, generating partial discharge and inducing material aging. Third, after lamination, there is a significant abrupt change in thickness at the location of the busbar, leading to mechanical stress concentration. Based on the aforementioned material aging, this easily results in glass breakage or damage.

[0028] Furthermore, the inventors of this application have discovered that if the flattening is performed after string welding, the welded battery string usually needs to be transferred and the lead-out end of the solder strip needs to be flattened. This requires additional loading, unloading, and transfer processes, which cannot be linked with the original string welding process. Moreover, flattening the solder strip after stringing inevitably causes vibration during the flattening process. Under the influence of vibration during flattening, electrical connection failures can easily occur at some electrical connection points within the battery string or module, affecting the stability and reliability of the module.

[0029] To address the aforementioned technical issues, the photovoltaic module solder strip processing method provided in this application involves flattening the solder strip during the pulling process from the feeding side to the welding side, and then cutting it so that the end of the solder strip retains a flat rolled section of a predetermined length. This flat rolled section serves as the welding part for leading out the busbar or as the welding part for welding the busbar in the solder strip extending beyond the cell string. Subsequently, the flat rolled section at the end of the solder strip will be welded to the busbar. Firstly, since the welding part in the solder strip that is welded to the busbar is a flat rolled section after being flattened, the height difference at the location of the busbar is reduced, stress concentration during lamination is reduced, the probability of glass breakage or microcracks is reduced, and the lifespan of the photovoltaic module is improved. Secondly, this application flattens the welding strip during the pulling process from the feeding side to the welding side, which is achieved during the strip pulling process of the stringing machine. The flattening of the welding strip is linked with the strip pulling process of the stringing machine. Without changing the core process of the original stringing machine or increasing the production cycle, the flattening and shaping of the lead-out end of the welding strip in the battery string is completed. This achieves linkage between flattening, strip pulling, and cutting, which is perfectly matched with the mass production cycle, resulting in high production efficiency and easy mass production. Thirdly, this application flattens the end of the welding strip before stringing. The vibration of flattening will not affect the electrical connection effect of the internal electrical connection position of the battery string or module, thus improving the stability and reliability of the module. Fourth, compared to the unflattened portion of the solder strip, the flat rolled section has a larger width. In photovoltaic modules, the flat rolled section is welded to the busbar. Therefore, it can increase the welding area between the solder strip and the busbar, improve the electrical connection effect, and increase the welding pull force. At the same time, the end position of the flat rolled section is the transition position between the beginning and end of the flattening. Compared to the middle position of the flattening, the width of this end position is relatively small. The cutting position is the non-end position of the flat rolled section, which can ensure that the width of the flat rolled section retained at the end of the solder strip is larger, which can further increase the welding area with the busbar, improve the electrical connection effect, and increase the welding pull force.

[0030] This application primarily addresses the aforementioned technical problems through a method for processing the solder strips of photovoltaic modules, and through a string welding machine, which is the primary implementer of this method. The following detailed description of this application is provided in conjunction with the accompanying drawings.

[0031] Figure 1 This is a flowchart illustrating the steps of a photovoltaic module solder strip processing method according to this application. (Refer to...) Figure 1 The method for processing the solder strip of photovoltaic modules provided in this application includes the following steps.

[0032] Step S1, Rolling step: During the process of pulling the welding strip from the feeding side to the welding side, a local section of the welding strip is rolled at a preset flattening position, so that the thickness of the local section is reduced and the width is increased, forming a flat rolled section.

[0033] The feeding side is mainly used to accommodate or place the welding strip. For example, the welding strip can be wound on a welding strip reel; here, the feeding side refers to the welding strip reel. The welding side refers to the position in the stringer where the welding strip is welded onto the solar cell. The entity that performs the pulling and rolling of the welding strip can be... Figure 2 The welding machine 200 shown uses a pull handle 21 to pull the welding strip from the feeding side to the welding side. (Refer to...) Figure 3 , Figure 3 This is a schematic diagram of the solder strip 1 pulled out from the solder strip supply side. Before rolling, the thickness and width of the solder strip 1 are roughly the same at various locations.

[0034] It should be noted that the shape of the solder strip before rolling is not limited. For example, the solder strip before rolling can be a round solder strip or a flat solder strip.

[0035] Reference Figures 13 to 16 In a predetermined flattening position, a localized area of ​​the solder strip 1 is rolled to reduce the thickness and increase the width of that localized section, forming a flat rolled section 11. For example, refer to... Figure 2 , Figure 4 and Figure 5 The flattening mechanism of the 200-speed string welding machine can be used to perform the rolling action here. The flattening mechanism is set in the pulling path of the puller, and after pulling a certain distance, it flattens or rolls the wire, and then continues to pull.

[0036] The puller draws the welding strip to the preset flattening position and then pauses its movement. The flattening mechanism then performs a rolling action. After rolling is complete, the flattening pressure head lifts, and the puller draws the welding strip to the next station. The pause duration of the puller drawer can be set according to the rolling cycle of the flattening mechanism to ensure that rolling is completely completed before resuming pulling. The pulling distance of the puller drawer can be precisely controlled by a servo motor encoder to ensure that the preset flattening position of the welding strip corresponds precisely to the position of the flattening mechanism. The movement of the welding strip or battery string can be achieved through the transmission mechanism 24. During the flattening process, the welding strip can be in a stopped state to ensure the accuracy of the rolling position and the consistency of the flattened section size. The transmission mechanism can be a conveyor belt, etc., and is not limited thereto.

[0037] Step S2, First cutting step: Pull the welding strip to the preset cutting position and clamp it, cut the non-end position of the flat rolled section, so that the end of the welding strip retains a flat rolled section of a predetermined length as the lead-out busbar welding part.

[0038] Reference Figures 6 to 8 After clamping the solder strip 1, the non-end positions of the flat rolled section 11 are cut, so that the end of the solder strip 1 (cut position 13) retains a flat rolled section 11 of a predetermined length, which serves as the lead-out busbar welding part, or the welding part in the solder strip extending beyond the battery string for welding with the busbar. (Refer to...) Figures 9 to 12The flat rolled section 11 retained at the end of the solder ribbon 1 extends beyond the battery string 300 and is welded to the busbar 4. Other portions of the solder ribbon 1 can be electrically connected to the electrical connection portion 31 of the battery cell. This electrical connection portion 31 can be a solder pad, etc. During the cutting process, clamping the solder ribbon 1 allows for precise cutting. Cutting can be performed using the cutting mechanism of the string welding machine 200. The non-end position refers to the area of ​​the flat rolled section in the solder ribbon extension direction excluding the transition areas at both ends. In some embodiments, the cutting position is located within 30% to 70% of the total length of the flat rolled section, such that the ratio of the length of the flat rolled section retained on one side of the battery string after cutting to the length of the flat rolled section remaining on the feeding side is between 0.4:1 and 2.3:1. In some embodiments, the cutting position is located at the midpoint of the flat rolled section (i.e., a centered cut), such that the lengths retained at both ends are approximately equal. The cutting position should avoid the transition area at the beginning and end of the flat rolled section, where the width and thickness change drastically. Avoiding this area ensures that the remaining flat rolled section has a more uniform width and thickness, which is beneficial to the consistency and reliability of subsequent welding with the busbar.

[0039] Compared to the unflattened portion of the solder strip, the flat rolled section 11 has a larger width. In photovoltaic modules, the flat rolled section is welded to the busbar. Therefore, the welding area between the solder strip 1 and the busbar 4 can be increased, improving the electrical connection effect and welding pull force. At the same time, the end position of the flat rolled section 11 is the beginning and end position of the flattening. Compared to the middle position of the flattening, the width of this end position is relatively small. The cutting position is the non-end position of the flat rolled section 11, which can ensure that the width of the flat rolled section 11 retained at the end of the solder strip 1 is larger, which can further increase the welding area with the busbar, improve the electrical connection effect and welding pull force.

[0040] In this application, firstly, the welding portion of the welding strip 1 that is welded to the busbar 4 is a flattened, rolled section 11, which reduces the height difference at the location of the busbar 4, reduces stress concentration during lamination, reduces the probability of glass breakage or microcracks, and improves the lifespan of the photovoltaic module. Secondly, this application flattens the welding strip 1 during the pulling process from the feeding side to the welding side, that is, it achieves flattening in the stringing machine's pulling process. The flattening of the welding strip 1 is linked with the stringing machine's pulling process, completing the flattening and shaping of the lead-out end of the welding strip 1 in the battery string 300 without changing the original core process of the stringing machine or increasing the production cycle, perfectly matching the mass production cycle and achieving high production efficiency. Thirdly, this application flattens the end of the welding strip 1 before stringing, so the vibration of flattening will not affect the electrical connection effect of the battery string or the internal electrical connection position of the module, improving the stability and reliability of the module.

[0041] Reference Figures 9 to 12A cell string is the main power generation unit in a photovoltaic module. A cell string includes a solder ribbon 1 and several cells 3. The solder ribbon 1 electrically connects adjacent cells 3. Within the same cell string, cells can be connected in series. The number of cell strings in a photovoltaic module is not limited. A cell is the main power generation unit in the cell string. A cell has opposing light-facing and back-facing sides, and is a bifacial solar cell with electrode structures on both the light-facing and back-facing sides, such as a TOPcon (tunneling oxide passivated contact) cell. Alternatively, the cell can be a back-contact solar cell with an electrode structure only on the back-facing side, such as a heterojunction with back contact (HBC) solar cell or a back-contact TBC (tunneling oxide passivated back contact) cell. The cell can be a half-cell formed by cutting a whole cell in half, or a segmented cell formed by dividing a whole cell into multiple segments. Cells can be stacked to form a cell string, or gaps can exist between adjacent cells within the cell string; all of these are within the scope of protection of this application. The specific material of the solder strip is not limited. For example, the material of the solder strip can be tin-plated copper strip, with the base material being rolled copper, which has the characteristics of high conductivity and low resistance. The coating layer is tin-lead or tin-lead-bismuth alloy, the main function of which is to protect the copper base from oxidation when exposed to air, and to alloy it during welding to ensure the welding effect. As another example, the base material of the solder strip can be copper-aluminum, such as copper-clad aluminum.

[0042] Figures 9 to 12 This is a top view of the battery string. Figure 13 and Figure 15 This is a partial top view of the solder strip. Figure 14 yes Figure 13 Corresponding cross-sectional diagram, Figure 16 yes Figure 15 The corresponding cross-sectional diagram.

[0043] In some embodiments, the thickness reduction rate of the local segment undergoing calendering is 20% to 80%, and the width increase rate is 50% to 250%. Based on the principle of constant volume during calendering, the cross-sectional area of ​​the weld strip remains essentially unchanged before and after calendering; therefore, there is a corresponding relationship between the thickness reduction rate and the width increase rate. For example, a weld strip with an initial thickness of 0.25 mm and an initial width of 0.8 mm, after calendering, has its thickness reduced to 0.1 mm (a reduction rate of approximately 60%). Based on the principle of constant cross-sectional area, the theoretical width increases to approximately 2.0 mm (an increase rate of approximately 150%). In actual calendering processes, due to differences in material ductility, calender die shape, and process parameters, the actual value of the width increase rate may deviate slightly from the theoretical calculation value. However, the trends of the thickness reduction rate and the width increase rate are opposite, and their values ​​are correlated.

[0044] Reference Figures 13 to 16The thickness reduction rate is calculated as (h1 - h2) / h1, where h1 is the initial thickness of a local section of the solder strip before rolling, or the initial thickness of the solder strip, and h2 is the thickness of the flat rolled section. The width increase rate is calculated as (w2 - w1) / w1, where w1 is the initial width of the solder strip or the initial width of a local section of the solder strip before rolling, and w2 is the width of the flat rolled section. If the thickness reduction rate and width increase rate are too high, rolling becomes difficult to achieve, and the solder strip is also prone to mechanical defects such as breakage. If the thickness reduction rate and width increase rate are too low, the improvement effect on glass breakage or damage is poor. Therefore, if the thickness reduction rate and width increase rate are within the above range, rolling is easy to achieve, the various properties of the solder strip are good, and the risk of glass breakage or damage is low. For example, in the local section where calendering is performed, the thickness reduction rate can be 20%, 30%, 40%, 50%, 60%, 70%, 80%, and the width increase rate can be 50%, 80%, 90%, 100%, 120%, 150%, 190%, 200%, 220%, 250%.

[0045] In some embodiments, refer to Figures 9 to 16 The initial thickness H1 of the portion of the solder strip 1 excluding the flat rolled section 11 is 0.13 mm to 0.4 mm, and the initial width W1 is 0.4 mm to 1.2 mm. The thickness H2 of the flat rolled section 11 is 0.05 mm to 0.15 mm, and the width W2 is 0.8 mm to 2.2 mm. Rolling is easy to achieve, and the solder strip has good properties, with a low risk of glass breakage or damage. For example, H1 can be 0.13 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.23 mm, 0.25 mm, 0.28 mm, 0.3 mm, 0.32 mm, 0.35 mm, 0.37 mm, or 0.4 mm. For example, W1 can be 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.1 mm, or 1.2 mm. For example, H2 can be 0.05mm, 0.08mm, 0.1mm, 0.12mm, 0.14mm, or 0.15mm. For example, W2 can be 0.8mm, 1mm, 1.2mm, 1.5mm, 1.7mm, 2mm, or 2.2mm.

[0046] For example, H1 can be 0.25mm, W1 can be 1mm, H2 can be 0.12±0.02mm, and W2 can be 2.08±0.25mm. For example, H1 can be 0.25mm, W1 can be 0.8mm, H2 can be 0.12±0.02mm, and W2 can be 1.67±0.2mm. For example, H1 can be 0.25mm, W1 can be 0.6mm, H2 can be 0.12±0.02mm, and W2 can be 1.25±0.15mm. For example, H1 can be 0.2mm, W1 can be 1mm, H2 can be 0.12±0.02mm, and W2 can be 1.67±0.2mm. For example, H1 can be 0.2mm, W1 can be 0.8mm, H2 can be 0.12±0.02mm, and W2 can be 1.33±0.15mm. For example, H1 can be 0.2mm, W1 can be 0.6mm, H2 can be 0.12±0.02mm, and W2 can be 1±0.1mm.

[0047] It should be noted that, referring to Figures 9 to 16 H1 can be a thickness at any location in the solder strip before rolling, or the average of the thicknesses at multiple locations, or a thickness at any location outside the flat rolled section after rolling, or the average of the thicknesses at multiple locations. W1 can be a width at any location in the solder strip before rolling, or the average of the widths at any location outside the flat rolled section after rolling, or the average of the widths at multiple locations. H2 can be a thickness at or near the location with the minimum thickness in the flat rolled section 11, or the average of the thicknesses at or near the location with the maximum width in the flat rolled section 11, or the average of the widths at or near the location with the maximum width.

[0048] In some embodiments, refer to Figure 13 and Figure 15 Before cutting, the length L1 of the flat rolled section 11 is 5mm to 12mm. If L1 is too small, there will still be unflattened parts in the weld strip that are electrically connected to the busbar, which is not good for improving the glass breakage or damage, as well as improving the welding tensile electrical connection effect. At the same time, it requires high process requirements at the cutting position. If L1 is too large, there will be serious waste of weld strip in the case of discarding scrap. Therefore, in this application, L1 is within the above range, which not only has a good effect on improving the glass breakage or damage and improving the welding tensile electrical connection effect, but also has a wide process window at the cutting position, while avoiding excessive waste of weld strip. For example, L1 can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, or 12mm.

[0049] In this application, the length L1 of the flat rolled section 11 is in the direction along the extension direction of the solder strip, and the width of the flat rolled section 11 is in the direction perpendicular to the extension direction of the solder strip.

[0050] In some embodiments, refer to Figure 8 After cutting, the end of the solder strip retains a flat rolled section 11 of a predetermined length, L2, which is 3mm to 7mm. If L2 is too small, there will still be unflattened portions in the solder strip that are electrically connected to the busbar, resulting in poor improvement in glass breakage or damage, as well as in the improvement of welding tensile strength and electrical connection. If L2 is too large, the size of the flat rolled section 11 may be too large, potentially causing optical loss. Therefore, in this application, L2 is within the above-mentioned range, which not only effectively improves glass breakage or damage and the improvement of welding tensile strength and electrical connection, but also prevents the size of the flat rolled section 11 from becoming too large. For example, L2 can be 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, or 7mm.

[0051] In some embodiments, refer to Figures 13 to 16 Before cutting, in the extension direction X of the solder strip 1, the width W2 of the flat rolled section 11 first increases and then decreases, and / or the thickness H2 of the flat rolled section 11 first decreases and then increases. Consequently, the thickness H2 of the flat rolled section 11 is smaller and the width W2 is larger at the middle position. The middle position of the flat rolled section 11 is roughly the retained position. Therefore, the flat rolled section retained at the end of the solder strip has a smaller thickness and a larger width, which not only further reduces the risk of glass breakage or damage, but also further increases the welding area with the busbar, improves the electrical connection effect, and increases the welding tensile strength. In addition, the dimensions of the flat rolled section 11 and the rest of the solder strip transition smoothly, avoiding mechanical damage to the solder strip.

[0052] In this application, before cutting, in the extension direction X of the solder strip 1, the width W2 of the flat rolled section 11 first increases and then decreases. In this application, as long as there is a trend of first increasing and then decreasing, the degree or manner of increase or decrease is not limited. Similarly, the change in thickness is only required to have a corresponding trend, and the degree or manner of change is not limited.

[0053] Figure 13 This is a top view of the solder strip. Figure 14 for Figure 13 A schematic cross-sectional view of the solder strip is shown. In some embodiments, refer to... Figure 13 and Figure 14Before cutting, in the extension direction X of the solder strip 1, the width W2 of the flat rolled section 11 first increases, then remains approximately equal for a period, and then decreases. This period of increasing or decreasing width W2 is called the transition section. Therefore, in the extension direction X of the solder strip 1, the length of the transition section located on one side of the middle position of the flat rolled section 11 can be 1 / 6 to 1 / 10 of the length L1 of the flat rolled section 11. Through this transition section of the aforementioned dimensions, the dimensions of the flat rolled section 11 and the rest of the solder strip transition smoothly, avoiding mechanical damage to the solder strip.

[0054] In some embodiments, the projected shape of the flat rolled section before cutting is at least one of a shuttle shape, a rounded rectangle, or a rounded-side ellipse. These shapes are easy to form during rolling, and their outlines are relatively smooth, with virtually no stress concentration issues. The projection of the flat rolled section refers to the projection of the flat rolled section onto adjacent surfaces when illuminated by light parallel to the thickness direction of the solder strip.

[0055] Reference Figure 15 The spindle shape mentioned in this application refers to a spindle-shaped or date-shaped structure that is wider in the middle and tapered at both ends. Figure 15 This is a schematic diagram of a shuttle shape. (See reference...) Figure 13 This is a schematic diagram of a flat, rolled section with rounded corners. A rounded rectangle is a shape created by rounding the right-angled sides of a rectangle to form a smooth transition. A rounded-corner ellipse-like shape refers to a closed curve that resembles an ellipse in appearance but has local rounded corner transitions.

[0056] In some embodiments, refer to Figures 9 to 12The solder strips include: a first group of solder strips and a second group of solder strips, wherein the number of solder strips in both the first and second groups is greater than 1. The rolling step includes: rolling local sections of each solder strip in the first group of solder strips, and / or rolling local sections of each solder strip in the second group of solder strips. As long as local sections of each solder strip in at least one of the first and second groups of solder strips are rolled, it is within the scope of protection of this application. After cutting: along the extension direction X of the battery string, the first group of solder strips is located at the head of the battery string, and the second group of solder strips is located at the tail of the battery string. Along the second direction Y, the solder strips in the first group of solder strips and the solder strips in the second group of solder strips are staggered. In some embodiments, along the second direction Y, the solder strips in the first group of solder strips and the solder strips in the second group of solder strips appear alternately, that is, in the second direction Y, one solder strip in the first group of solder strips is followed by one solder strip in the second group of solder strips, and then another solder strip in the first group of solder strips, and so on. In the extension direction X of the battery string, the first and second sets of solder ribbons are not aligned. At the same time, in the second direction Y, the first and second sets of solder ribbons are also not aligned. The cells in this photovoltaic module are back-contact cells. Since the positive and negative electrode structures of the back-contact cells are both located on the back side, the first and second sets of solder ribbons are staggered along the second direction Y and the extension direction X of the battery string.

[0057] The specific manifestation of the misaligned arrangement is as follows: In the extension direction X of the battery string, the lead-out ends of the first group of solder ribbons and the second group of solder ribbons are not on the same straight line, and there is an offset between them in the second direction Y. The first group of solder ribbons can correspond to the positive electrode of the back contact cell, and the second group of solder ribbons can correspond to the negative electrode of the back contact cell. Since the positive and negative electrodes are arranged alternately in the second direction Y on the back of the cell, the two groups of solder ribbons naturally form a misalignment at the lead-out ends. Along the extension direction X of the battery string, for the solder ribbons in the middle position of the battery string, since they do not need to be welded to the busbars at the beginning and end of the battery string, whether they are flattened is not limited. Therefore, the solder ribbons located in the middle position of the battery string may not belong to the first group of solder ribbons or the second group of solder ribbons. The solder ribbons in the middle position of the battery string can correspond to the positive electrode or the negative electrode of the back contact cell. For back-contact battery modules, the solder strips need to be staggered from both ends of the battery string and arranged in a staggered manner along the direction intersecting with the extension direction of the battery string. Conventional single flattening devices are difficult to adapt to this staggered layout, which restricts the efficient production of back-contact battery modules. Therefore, in this application, an independent rolling unit is used to roll the leads of the two sets of solder strips separately to solve the problem that conventional single rolling devices cannot simultaneously adapt to the rolling requirements of two sets of staggered solder strips.

[0058] In back-contact solar cells, all electrode structures are arranged on the back side of the cell, with no obstruction on the front or light-facing side, maximizing light absorption. Due to reduced light loss from shading, the photoelectric conversion efficiency of the cell is higher than that of traditional cells; for example, the efficiency of back-contact solar cells can typically reach 25% (the specific efficiency depends on the technology and materials). Back-contact solar cells reduce the impact of microcracks in the front electrodes, resulting in greater durability and reliability. The absence of electrode structures on the front of back-contact solar cells creates a unified and aesthetically pleasing appearance, making them ideal for building-integrated photovoltaics (BIPV) and high-end applications. However, because both the positive and negative electrode structures of back-contact solar cells are concentrated on the back side, more electrode paste is used on the back, leading to higher stress on one side. Therefore, greater tensile force and better current collection are required at the welding end. In this application, at the electrical connection point between the busbar and the solder strip, the end of the solder strip is flattened, increasing the contact area between the solder strip and the busbar, which increases the welding tensile force and improves current collection, thereby enhancing module power and reliability.

[0059] It should be noted that the number of solder ribbons in the first group can be equal to the number of solder ribbons in the second group, or the difference between them can be 1. When the number of solder ribbons on the backside of a solar cell is even, the number of solder ribbons in the first group can be equal to the number of solder ribbons in the second group. When the number of solder ribbons on the backside of a solar cell is odd, the difference between the number of solder ribbons in the first group and the number of solder ribbons in the second group can be 1.

[0060] In some embodiments, the pull handle 21 of the string welding machine 200 may include: two pull handles, one of which pulls out a first set of welding strips, and the other pull handle pulls out a second set of welding strips. The two pull handles can work simultaneously to improve the pulling efficiency. The two pull handles can be set in different positions to meet the pulling requirements of misaligned photovoltaic module welding strips corresponding to the back contact cells. The two pull handles can pull simultaneously or sequentially, which is within the protection scope of this application; or, the pull handle includes: one pull handle, which sequentially pulls out the first set of welding strips and the second set of welding strips. The pulling process of the first set of welding strips and the second set of welding strips will not interfere with each other.

[0061] Figure 2 In this process, the first group of welding strips is cut by the first cutting mechanism 231, and the second group of welding strips is cut by the second cutting mechanism 232. Specifically, before cutting, the first group of welding strips is clamped by the first clamping band 2312 and cut by the first cutter 2311, and the second group of welding strips is clamped by the second clamping band 2322 and cut by the second cutter 2321.

[0062] For example, Figure 2There is only one pull handle 21, with solder strip reels on both sides. The pull handle 21 has a first gripper 211 and a second gripper 212 arranged opposite to each other in the extension direction X of the battery string. The first gripper 211 can first pull out the first set of solder strips from the solder strip reel on the side closer to the cross-dash arrow in the extension direction X of the battery string, and pull it to the first flattening mechanism 221. Then, the second gripper 212 pulls out the second set of solder strips from the solder strip reel on the side away from the cross-dash arrow in the extension direction X of the battery string, and pulls it to the second flattening mechanism 222. Since the spacing between adjacent solder strips in the second direction Y of the photovoltaic module may be small, in this application, the first set of solder strips and the second set of solder strips are pulled out sequentially by the pull handle, which reduces mutual interference and makes the pulling smoother.

[0063] The second direction Y intersects the extension direction X of the battery string, and the angle between them is not limited; for example, it can be 90° or close to 90°, such as 80° to 100°. For example, Figures 9 to 12 In the battery string, along the extension direction X, the side of the battery string closer to the cross-shaped dotted arrow is the head position of the battery string, and the side farther away from the cross-shaped dotted arrow is the tail position of the battery string. The solder strips that are not parallel in the extension direction X and are located at the head position of the battery string are the first group of solder strips, and the solder strips located at the tail position of the battery string are the second group of solder strips.

[0064] It should be noted that, Figures 9 to 12 This is merely an illustration of a battery string and does not specify the number of solder strips in the first and second groups of solder strips in the battery string.

[0065] In some embodiments, refer to Figure 2 For situations where both the first and second groups of solder strips need to be flattened, the flattening mechanism includes: a first flattening mechanism 221 and a second flattening mechanism 222. The first flattening mechanism 221 rolls the first group of solder strips, and the second flattening mechanism 222 rolls the second group of solder strips. The flattening of the two groups of solder strips can be performed simultaneously, improving flattening efficiency. The two flattening mechanisms can be set in different positions to meet the flattening requirements of misaligned photovoltaic module solder strips corresponding to the back contact cells. Both flattening mechanisms can roll simultaneously or sequentially, both within the scope of protection of this application. Alternatively, the flattening mechanism includes: a single flattening mechanism that rolls the first and second groups of solder strips sequentially, reducing the number of flattening mechanisms.

[0066] Figure 4 for Figure 2 A magnified view of the area corresponding to position C in the diagram. Figure 5 for Figure 4 A partially enlarged schematic diagram of the cross section containing the dashed ellipse. In some embodiments, refer to... Figure 2 , Figure 4 and Figure 5The flattening mechanism includes: a support base 223; a support plate 224 fixed to the support base 223, the support plate 224 including a welding strip bearing surface for bearing the welding strip to be flattened or rolled; a flattening pressure head 225, disposed opposite to the support plate 224; and a lifting drive 226 connected to the flattening pressure head 225, driving the flattening pressure head 225 to move closer to or away from the support plate 224. Moving the flattening pressure head 225 closer to the support plate 224 allows for rolling of the welding strip; moving the flattening pressure head 225 away from the support plate 224 allows the welding strip, battery string, etc., to continue moving on the transmission mechanism 24. The support base 223 provides support for the flattening mechanism, and the welding strip bearing surface of the support plate 224 serves as the operating table for flattening or rolling.

[0067] In some embodiments, the welding strip bearing surface of the support pad 224 can be flush with the welding strip conveying surface of the welding machine's tape pulling path, so there is no height difference between the welding strip pulling and flattening positions, eliminating the need for lifting and lowering, and simplifying the structure. For example, the welding strip conveying surface of the welding machine's tape pulling path is the transmission mechanism 24, and the welding strip bearing surface of the support pad 224 can be flush with the transmission surface of the transmission mechanism 24.

[0068] In some embodiments, the welding strip bearing surface of the support plate 224 of the flattening mechanism is provided with multiple limiting grooves for positioning the welding strip, ensuring that the welding strip will not shift laterally during the flattening process, and making the flattening or rolling action position more precise.

[0069] In some embodiments, the lifting drive 226 of the flattening mechanism may include one of a cylinder, a servo cylinder, or a linear motor. The above-mentioned lifting drive is common and readily available.

[0070] In some embodiments, refer to Figure 9 and Figure 11 In a battery string of 300, the number of battery cells 3 is m, where m is an odd number. For example, Figure 9 and Figure 11 In this context, m is always 3. When the number of solar cells m is odd, the lead-out strips at the head and tail of the solar cell string belong to different strip groups. The rolling process includes: rolling local sections of each strip in the first group and rolling local sections of each strip in the second group. (Refer to...) Figures 6 to 8In the first cutting step, the cutting position only needs to be offset from the end position of the flat rolled section. After cutting: along the extension direction X of the battery string, the flat rolled section 11 of the first group of solder strips is located on the side away from the tail of the battery string, and the flat rolled section 11 of the second group of solder strips is located on the side away from the head of the battery string. The flat rolled section 11 of the first group of solder strips exists as a welding part for welding with the busbar in the solder strip extending beyond the head of the battery string, and the flat rolled section 11 of the second group of solder strips exists as a welding part for welding with the busbar in the solder strip extending beyond the tail of the battery string. Since the cutting position is located at a non-end position of the flat rolled section, after cutting, in addition to the predetermined length of the lead-out flat section remaining on one side of the battery string, a section of flat rolled section also remains at the end of the solder strip on the feeding side (i.e., the residual flat rolled section on the feeding side). The thickness and width of the residual flat rolled section are the same as or similar to the lead-out flat section. For an odd-numbered cell configuration, the first and second sets of solder strips each produce a residual flat rolled section, for a total of two sections. If these residual flat rolled sections are not removed, they will enter the welding area of ​​the cell string during the next round of strip pulling, which may lead to poor welding with the electrical connection of the cell, or cause a short circuit risk due to their thinness and width, contact with non-insulated areas.

[0071] The method further includes a residual material removal step: at the beginning of the next round of strip pulling, the remaining flat rolled sections on the feeding side of the first and second sets of welding strips are pulled out to a first preset length, and the remaining flat rolled sections are cut off and discarded. This ensures that the exposed cross-section of the welding strip on the feeding side is still the original cross-section before the welding strip is flattened, guaranteeing that the end of the welding strip entering the welding area is the initial un-rolled cross-section to meet the welding requirements of the corresponding position. Additionally, this prevents the remaining flat rolled sections from welding into the battery cell, or in other words, prevents the remaining flat rolled sections from easily contacting the battery cell and causing a short circuit due to contact with a non-insulating component. The first preset length here can be greater than or equal to the length of the remaining flat rolled section on the feeding side, ensuring that all remaining flat rolled sections on the feeding side are removed. For example, the first preset length here can be equal to the length L1 of the flat rolled section before cutting. Another example is that the first preset length here can be 8mm to 11mm.

[0072] For example, Figure 9 and Figure 11In the battery string extension direction X, the side closer to the cross-shaped dotted arrow is the head position of the battery string, and the side farther from the cross-shaped dotted arrow is the tail position. The solder strips that are not parallel in the extension direction X and extend beyond the head position of the battery string are the first group of solder strips, and the solder strips that extend beyond the tail position of the battery string are the second group of solder strips. The flat rolled section 11 of each solder strip in the first group extends beyond the head position of the battery string and is welded to the busbar 4 near the head position. The flat rolled section 11 of each solder strip in the second group extends beyond the tail position of the battery string and is welded to the busbar 4 near the tail position.

[0073] Figure 9 and Figure 11 The difference lies in the number of solder ribbons on a single solar cell. Figure 9 In this context, the number of solder strips corresponding to a single solar cell is an even number. Figure 11 In this case, the number of solder strips corresponding to a single solar cell is odd.

[0074] In some embodiments, refer to Figure 10 and Figure 12 In a battery string of 300, the number of battery cells 3 is m, where m is an even number. For example, Figure 10 and Figure 12 In this context, m is always 4. When the number of solar cells m is even, the lead-out strips at the head and tail of the solar cell string belong to the first group of lead-out strips. The two ends of the second group of lead-out strips terminate inside the solar cell string, without creating lead-out ends. The rolling process includes rolling only local sections of each lead-out strip in the first group. (Refer to...) Figure 6 and Figure 8In the first cutting step, the flat rolled section 11 is cut in the center along the extension direction X of the battery string. The length of the flat rolled section 11 at the end of each solder strip in the first group is approximately equal to the length of the flat rolled section remaining on the feeding side corresponding to each solder strip in the first group. The method further includes a second cutting step, in which the remaining flat rolled section on the feeding side corresponding to the first group of solder strips is pulled out to a second preset length and cut to obtain a third group of solder strips. The ends of the solder strips in the third group retain the flat rolled section formed by the center cut. The third group of solder strips corresponds to the feeding side of each solder strip in the first group, and the length of the flat rolled section 11 at the end of each solder strip in the first group is approximately equal to the length of the flat rolled section of each solder strip in the third group. After cutting: Along the extension direction X of the battery string, the flat rolled section 11 of the first group of solder strips is located on the side away from the tail of the battery string, and the flat rolled section 11 of the third group of solder strips is located on the side away from the head of the battery string. The flat rolled section 11 of the first group of solder strips exists as the welding part of the solder strips extending beyond the head of the battery string and being welded to the busbar. The flat rolled section 11 of the third group of solder strips exists as the welding part of the solder strips extending beyond the tail of the battery string and being welded to the busbar. That is, the third group of solder strips is transformed from the residual flat rolled section of the first group of solder strips. Its flat rolled section is formed by cutting in the middle and is used for leading out at the tail of the next battery string in even-numbered schemes. In this case, the residual flat rolled section on the feeding side corresponding to the first group of solder strips is not cut off and discarded, reducing waste and lowering costs. At the same time, the flat rolled sections of the solder strips located at the head and tail of the battery string are formed in one flattening process, reducing the number of flattening times and improving production efficiency. In the extending direction X of the battery string, each solder strip in the first group and each solder strip in the third group are arranged at least partially in parallel. The second preset length here can be approximately equal to the length of the portion of the first group of solder strips excluding the flat rolled section, thereby ensuring that the lengths of the first and third groups of solder strips are approximately equal. Alternatively, this second preset length can be set according to specific welding requirements, and this application does not limit it in this regard.

[0075] For example, Figure 10 and Figure 12In the battery string, along the extension direction X, the side of the battery string closer to the crossed dotted arrow is the head position, and the side farther from the crossed dotted arrow is the tail position. The solder strips that do not coexist in the extension direction X and extend beyond the head position are the first group of solder strips. The solder strips located at the tail position are the second group of solder strips. The solder strips that coexist in the extension direction X and extend beyond the tail position are the third group of solder strips. The flat rolled section 11 of each solder strip in the first group extends beyond the head position of the battery string and is welded to the busbar 4 near the head position. The flat rolled section 11 of each solder strip in the third group extends beyond the tail position of the battery string and is welded to the busbar 4 near the tail position.

[0076] Figure 10 and Figure 12 The difference lies in the number of solder ribbons on a single solar cell. Figure 10 In this context, the number of solder strips corresponding to a single solar cell is an even number. Figure 12 In this case, the number of solder strips corresponding to a single solar cell is odd.

[0077] In some embodiments, the method may further include: welding the flat rolled section 11 of the welding strip 1 to the busbar 4, and bending the welding strip 1 so that the lead-out busbar welding part or the flat rolled section 11 and the busbar 4 welded thereto are located on the back side of the battery string. By folding, the busbar 4 is hidden on the back side of the photovoltaic module, which reduces the space occupation of the busbar 4 in the length direction X of the battery string. This not only reduces shading, but also increases the space utilization of the photovoltaic module on the basis of the same module size, thereby improving the power generation capacity of the photovoltaic module.

[0078] In some embodiments, during the rolling step, a localized section of the solder strip is heated; and / or, before the rolling step, the method may further include heating a localized section of the solder strip. This localized area is the flattened region. Heating the flattened region of the solder strip can improve its ductility, enhance the flattening or rolling effect, reduce the risk of brittle fracture of solder strips made of different materials, and improve material compatibility. In this application, heating may not be necessary for the portion of the solder strip outside the flattened or rolled area, thus avoiding the impact of heating on this portion.

[0079] In some embodiments, the flattening head 225 of the flattening mechanism of the string welding machine 200 includes a heating structure for heating a local section of the welding strip during the rolling process. Integrating the heating structure into the flattening head 225 achieves heating only at the flattening position of the welding strip, and the flattening mechanism has a compact structure, reducing the space occupied.

[0080] It should be noted that the methods for processing the solder ribbons of photovoltaic modules and the related content of string welding machines can be referred to interchangeably. To avoid repetition, the relevant parts will not be repeated. The foregoing embodiments of this application can be implemented individually or in combination without logical conflict, and this application does not limit this.

[0081] The following specific examples will further explain this application.

[0082] Example 1 The specifications of the welding strip are 0.25 × 0.8 (thickness × width). In this example, the initial cross-section of the welding strip can be approximated as rectangular (i.e., flat welding strip). For welding strips with an initial circular cross-section, flat rolled sections can also be formed in local areas after rolling. The thickness and width variation patterns are similar to those of flat welding strips. The difference is that the width of the circular welding strip increases more significantly after rolling, and the cross-sectional shape after rolling tends to be elliptical or rounded rectangle. The main execution body is a string welding machine. The welding strip consists of only one set of welding strips. The string welding machine includes a pulling arm, a flattening mechanism, and a cutting mechanism. During the process of pulling the welding strip from the feeding side to the welding side, the pulling hand pauses after pulling it out by about 1 meter. It then reaches the preset flattening position of the flattening mechanism. The flattening mechanism rolls a local section of the welding strip, reducing its thickness and increasing its width to form a flat rolled section. The thickness of the flat rolled section is 0.1±0.02mm, its width is 1.67mm±0.2mm, and its length is 6mm±1.5mm. The flattening head of the flattening mechanism is lifted, and then the pulling hand continues to pull the welding strip to the preset cutting position of the cutting mechanism. After clamping the welding strip, the non-end positions of the flat rolled section are cut, leaving a predetermined length of flat rolled section at the end of the welding strip. This flat rolled section serves as the welding part for welding to the busbar in the welding strip that extends beyond the battery string. Subsequently, the welding strip is welded to the electrical connection part 31 of the battery cell, and the flat rolled section of the welding strip is welded to the busbar. The string welding machine's pull handle, flattening mechanism, and cutting mechanism are all connected to the string welding machine's control system to execute the aforementioned full-process linkage actions.

[0083] Example 1, or this application, implements an independent online flattening mechanism on the tape pulling path of the string welding machine. This mechanism works in conjunction with the tape pulling hand and cutting structure throughout the entire process to achieve precise flattening and standardized cutting of the tape lead-out end, balancing mass production yield and efficiency, enabling mass production. Flattening before welding eliminates vibrations that could affect subsequent welding results, ensuring high welding reliability and stability. Furthermore, it eliminates the need for additional loading, unloading, and transfer processes, resulting in high production efficiency. In Example 1, during the mass production of 1000 photovoltaic modules, the dimensional consistency of the flattened rolling section is 100%. The rate of incomplete welds between the tape and busbar is below 0.5%, perfectly matching the original production cycle of the string welding machine without adding any extra processes. The production time per string remains essentially unchanged, resulting in minimal capacity loss. After welding the tape and busbar, the overall cross-sectional thickness is reduced by 30%, the tape positioning deviation defect rate drops to 0, and the equipment's continuous mass production uptime exceeds 95%.

[0084] In this application, 100% dimensional consistency of the flat rolled section means that during the mass production of 1000 photovoltaic modules, the thickness of each flat rolled section is within the set range and does not exceed the set thickness range. The cold solder joint rate of the solder strip and busbar refers to the proportion of photovoltaic modules with cold solder joints out of 1000 during the mass production of 1000 photovoltaic modules. If any one of the multiple solder joints of a photovoltaic module has a spot weld or a cold solder joint, the photovoltaic module is considered to have a cold solder joint. The continuous mass production uptime rate of the equipment refers to the proportion of the actual production time of the equipment or production line to the available load time during the mass production of 1000 photovoltaic modules, reflecting the true utilization efficiency of the equipment under mass production conditions. The solder strip positioning deviation defect rate refers to the proportion of photovoltaic modules with poor alignment between the solder strip containing the flat rolled section and the electrical connection part 31 on the solar cell, exceeding the set alignment accuracy, out of 1000 during the mass production of 1000 photovoltaic modules. If any one of the multiple electrical connection portions 31 of a photovoltaic module has an alignment accuracy problem with the solder strip containing the flat rolled section, and this alignment accuracy exceeds a set alignment accuracy, then the photovoltaic module is considered to have an alignment accuracy problem, or the alignment accuracy of the electrical connection portion 31 of the photovoltaic module with the solder strip containing the flat rolled section exceeds the set alignment accuracy. The reduction in overall cross-sectional thickness after solder strip and busbar welding refers to the average of the ratio of the original thickness of the overall cross-section after solder strip and busbar welding before flattening using the solder strip processing method of this application, to the original thickness, and the difference between the original thickness and the target thickness of the overall cross-section after flattening using the solder strip processing method of this application.

[0085] The following examples 2 to 4 mainly describe the differences from example 1. The similarities with example 1 and the test parameters, etc. can all be referred to example 1. To avoid repetition, they will not be repeated.

[0086] Example 2 Reference Figure 9 and Figure 11 The solar cells are back-contact cells. The solder strips include a first set and a second set, both sets arranged in a staggered manner along a second direction Y intersecting the extension direction of the solar cell string on the back side of the string. Meanwhile, refer to... Figure 2 , Figure 4 and Figure 5 The stringing machine includes a strip puller, two flattening mechanisms, and two cutting mechanisms. Strip reels are positioned on both sides. The strip puller 21 has a first gripper 211 and a second gripper 212 positioned opposite each other along the extension direction X of the battery string. The first gripper 211 pulls a first set of strips from the strip reel on the side closer to the crossed dotted arrow along the extension direction X of the battery string, and pulls it to the first flattening mechanism 221. Then, the second gripper pulls a second set of strips from the strip reel on the side away from the crossed dotted arrow along the extension direction X of the battery string, and pulls it to the second flattening mechanism 222. The first flattening mechanism 221 then rolls the first set of strips, and the second flattening mechanism 222 rolls the second set of strips. The first set of strips is cut by the first cutting mechanism 231, and the second set of strips is cut by the second cutting mechanism 232. After cutting: Along the extension direction X of the battery string, the flat rolled section 11 of the first set of solder strips is located on the side of the first set of solder strips away from the tail of the battery string, and the flat rolled section 11 of the second set of solder strips is located on the side of the second set of solder strips away from the head of the battery string. The flat rolled section 11 of the first set of solder strips exists as a welding part in the solder strips extending beyond the head of the battery string and is welded to the busbar, and the flat rolled section 11 of the second set of solder strips exists as a welding part in the solder strips extending beyond the tail of the battery string and is welded to the busbar.

[0087] In Example 2, the photovoltaic system corresponding to the photovoltaic modules can withstand voltages ranging from 1500V to 2500V. A withstand voltage test with a pulse voltage of 33.46KV was conducted, and in all 1000 photovoltaic modules, the photovoltaic glass and encapsulating film in each system remained intact and undamaged. The relevant content and other test parameters of Example 2 can be found in the description of Example 1, and will not be repeated here to avoid repetition.

[0088] Example 3 Reference Figure 10 and Figure 12Unlike Example 2, the number of cells in the battery string is m, where m is an even number. The core difference between Example 3 and Example 2 lies in the parity of the number of cells m. When m is odd (Example 2), the lead-out strips at the head of the battery string belong to the first group of lead-out strips, and the lead-out strips at the tail belong to the second group of lead-out strips. Both groups need to be rolled, and after cutting, each group produces a residual flat segment that needs to be cut off and discarded. When m is even (Example 3), the lead-out strips at the head and tail of the battery string both belong to the first group of lead-out strips. The two ends of the second group of lead-out strips terminate inside the battery string without producing lead-out ends. Therefore, only the first group of lead-out strips needs to be flattened, and the string welding machine can have only one flattening mechanism to roll the first group of lead-out strips. In the first cutting step, the flat rolled segment 11 is cut in the center along the extension direction X of the battery string. Then, the length of the flat rolled segment 11 at the end of each lead-out strip of the first group of lead-out strips is approximately equal to the length of the residual flat rolled segment on the feeding side corresponding to each lead-out strip of the first group of lead-out strips. By centering the cut, the remaining flat rolled sections on the supply side can be directly converted into the tail lead-out solder strips (third group of solder strips) of the next battery string without being discarded, thus saving solder strip material and reducing the number of flattening operations. The remaining flat rolled sections on the supply side corresponding to the first group of solder strips are pulled out to a second preset length and cut to obtain the third group of solder strips. The third group of solder strips is converted from the remaining flat rolled sections of the first group of solder strips. Its flat sections are formed by centering the cut and are used for the tail lead-out of the next battery string in even-numbered schemes. It corresponds to the supply side of each solder strip in the first group of solder strips. The length of the flat rolled sections 11 at the ends of each solder strip in the first group of solder strips is approximately equal to the length of the flat rolled sections of each solder strip in the third group of solder strips. After cutting: along the extension direction X of the battery string, the flat rolled sections 11 of the first group of solder strips are located on the side of the first group of solder strips away from the tail of the battery string, and the flat rolled sections 11 of the third group of solder strips are located on the side of the third group of solder strips away from the head of the battery string. The flat rolled section 11 of the first group of solder strips exists as a welding part in the solder strips that extend beyond the head of the battery string and are welded to the busbar. The flat rolled section 11 of the third group of solder strips exists as a welding part in the solder strips that extend beyond the tail of the battery string and are welded to the busbar.

[0089] The relevant content and test parameters of Example 3 can be found in the relevant records of Example 1 and Example 2. To avoid repetition, they will not be repeated.

[0090] Example 4 Example 4 is based on Examples 1 to 3, with the addition of a step: bending the solder strip so that the flat rolled section after welding and the busbar welded to it are located on the back side of the battery string.

[0091] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0092] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0093] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0094] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., 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 this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0095] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for processing the solder strip of a photovoltaic module, characterized in that, include: Rolling step: During the process of pulling the welding strip from the feeding side to the welding side, a local section of the welding strip is rolled at a preset flattening position, so that the thickness of the local section is reduced and the width is increased to form a flat rolled section. First cutting step: Pull the welding strip to the preset cutting position and clamp it, and cut the non-end position of the flat rolled section so that the end of the welding strip retains a flat rolled section of a predetermined length as the lead-out busbar welding part.

2. The method for processing the solder strip of a photovoltaic module according to claim 1, characterized in that, The welding strips include: a first group of welding strips and a second group of welding strips; The rolling step includes: rolling a local section of each of the first group of weld strips, and / or rolling a local section of each of the second group of weld strips. After cutting: Along the extension direction of the battery string, the first group of solder strips is located at the head of the battery string, and the second group of solder strips is located at the tail of the battery string. Along a second direction intersecting the extension direction of the battery string, each solder strip in the first group of solder strips and each solder strip in the second group of solder strips are staggered.

3. The method for processing the solder strip of a photovoltaic module according to claim 2, characterized in that, The number of battery cells in one of the battery strings is m, where m is an odd number; The rolling step includes: rolling local sections of each of the first group of weld strips, and rolling local sections of each of the second group of weld strips. The method further includes a residual material removal step: at the beginning stage of the next round of strip pulling, the remaining flat rolled sections on the feeding side of the first group of welding strips and the second group of welding strips are pulled out to a first preset length and the remaining flat rolled sections are cut off.

4. The method for processing the solder strip of a photovoltaic module according to claim 3, characterized in that, The first group of weld strips and the second group of weld strips are rolled simultaneously; or, the first group of weld strips and the second group of weld strips are rolled sequentially.

5. The method for processing the solder strip of a photovoltaic module according to claim 2, characterized in that, The number of battery cells in one of the battery strings is m, where m is an even number; The rolling step includes: rolling local sections of each of the first group of weld strips; In the first cutting step, the flat rolled section is cut in the center along the extension direction of the battery string; The method further includes a second cutting step: pulling out the flat rolled section remaining on the feeding side corresponding to the first group of welding strips to a second preset length, and cutting it to obtain a third group of welding strips.

6. The method for processing the solder strip of a photovoltaic module according to claim 1, characterized in that, In the extending direction of the solder strip, before cutting: the width of the flat rolled section first increases and then decreases, and / or, the thickness of the flat rolled section first decreases and then increases; and / or, Before cutting: The projected shape of the flat calendered section is at least one of the following: shuttle shape, rounded rectangle, and rounded-edge ellipse.

7. The method for processing the solder strip of a photovoltaic module according to claim 1, characterized in that, The thickness reduction rate of the local section undergoing calendering is 20% to 80%, and the width increase rate is 50% to 250%.

8. The method for processing the solder strip of a photovoltaic module according to claim 1, characterized in that, The initial thickness of the portion of the weld strip outside the flat rolled section is 0.13 mm to 0.4 mm, and the initial width is 0.4 mm to 1.2 mm. The thickness of the flat rolled section is 0.05 mm to 0.15 mm, and the width is 0.8 mm to 2.2 mm; and / or, Before cutting, the length of the flat rolled section is 5mm to 12mm; the direction of this length is along the extension direction of the weld strip; and / or, The predetermined length is 3mm to 7mm.

9. The method for processing the solder strip of a photovoltaic module according to any one of claims 1 to 8, characterized in that, Also includes: The welding strip is bent so that the flat rolled section and the busbar welded thereto are located on the back side of the battery string.

10. The method for processing the solder strip of a photovoltaic module according to any one of claims 1 to 8, characterized in that, During the rolling process, local sections of the solder strip are heated; and / or, Before the rolling step, the method further includes heating a local section of the solder strip.

11. A string welding machine, characterized in that, include: Pull handle, flattening mechanism, and cutting mechanism; The pull handle is used to pull the welding strip from the feeding side to the welding side; The flattening mechanism is located in the pulling path of the puller and is used to roll a local section of the welding strip to reduce the thickness and increase the width of the local section, forming a flat rolled section. The cutting structure is used to cut the non-end positions of the flat rolled section after the welding strip is pulled to the preset cutting position.

12. The string welding machine according to claim 11, characterized in that, The flattening mechanism includes: Support base; A support pad, fixed on the bearing base, has a weld strip bearing surface; The flattened pressure head is positioned opposite the support pad; A lifting drive unit is connected to the flattening head and is used to drive the flattening head to move towards or away from the support pad.

13. The string welding machine according to claim 12, characterized in that, The flattening head includes: a heating structure for heating a localized section of the solder strip during the rolling process; and / or, The lifting drive component includes one of: a cylinder, a servo electric cylinder, and a linear motor; and / or, The welding strip bearing surface is provided with multiple limiting grooves for positioning the welding strip and limiting its lateral displacement during the rolling process; and / or, The surface of the welding strip is flush with the surface of the welding strip conveyor in the pulling path of the string welding machine.

14. The string welding machine according to claim 11, characterized in that, The pull handle includes: two pull handles, one for pulling out a first group of welding strips and the other for pulling out a second group of welding strips; or, the pull handle includes: one pull handle for sequentially pulling out the first group of welding strips and the second group of welding strips; and / or, The flattening mechanism includes: a first flattening mechanism and a second flattening mechanism, wherein the first flattening mechanism is used to roll the first group of welding strips and the second flattening mechanism is used to roll the second group of welding strips; or, the flattening mechanism includes: a flattening mechanism for sequentially rolling the first group of welding strips and the second group of welding strips.

Images