Spot welding machine reverse bending mechanism and method of using same, photovoltaic module

Abstract

This invention relates to the field of photovoltaic cells, specifically to a bending mechanism for a stacking welding machine and its usage method, and a photovoltaic module, including pressure pins, suction nozzles, a lifting plate, and a driving mechanism. Multiple pressure pins and suction nozzles are disposed at the bottom of the lifting plate. The output end of the driving mechanism is connected to the lifting plate to drive the pressure pins and suction nozzles to move up and down. The pressure pins act on the non-busbar dense area of ​​a single cell, independently bending and shaping each cell in the cell string entering the stacking process. The suction nozzles are correspondingly disposed in the center area of ​​the cell, adsorbing and fixing the cell after bending for welding. This invention solves the problem of warping, microcracks, and even breakage of BC cells during the stacking process, resulting in a flatter cell string and thus improving module yield and reliability.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cells, and more specifically, to a shingling machine inversion mechanism and its usage method, and a photovoltaic module. Background Technology

[0002] With the continuous advancement of photovoltaic technology, the manufacturing process and performance of photovoltaic modules are also being continuously optimized. Among them, BC cells (back-contact cells), as a new type of photovoltaic cell technology, not only achieve higher photoelectric conversion efficiency due to their design feature of having all electrodes located on the back of the cell and no metal grid lines on the front, but also significantly improve the aesthetics of the module. This structure avoids the shading of light by the metal grid lines on the front of traditional cells, allowing more sunlight to be absorbed by the cell.

[0003] In the manufacturing process of photovoltaic modules, BC cells need to be connected in series to form a cell string through a welding process. During welding, insulating adhesive is used to fix the cell to the solder strip, and high-temperature heating is used to ensure a reliable connection between the solder strip and the cell. However, in actual production, it has been found that the cell is prone to warping after welding. Specifically, the insulating adhesive volatilizes and deforms during heating, and the solder strip experiences shrinkage stress after cooling. These factors combined result in a wavy, uneven appearance of the entire cell string. This warping is particularly pronounced at the first and last cells of the string due to stress concentration.

[0004] This warping issue poses a serious risk in subsequent lamination processes. The lamination process requires applying uniform pressure and heating the module for encapsulation, but warped cells are subjected to additional mechanical stress. When this stress exceeds the silicon wafer's tolerance limit, it can lead to microcracks or even cell breakage. While microcracks are difficult to detect with the naked eye, they significantly reduce the cell's power generation efficiency and lifespan; cell breakage directly causes module failure, severely impacting product yield. Summary of the Invention

[0005] The purpose of this invention is to provide a recurved mechanism for a stacking welding machine, which can solve the problem that BC solar cells are prone to warping, causing microcracks or even breakage during the stacking process, making the cell string flatter, thereby improving the module yield and reliability.

[0006] Another objective of this invention is to provide a method for manufacturing BC battery modules, which can solve the problem that BC battery cells are prone to warping, causing microcracks or even breakage during the stacking process, making the battery strings flatter, thereby improving the module yield and reliability.

[0007] The technical solution of this invention is implemented as follows: A stacking welding machine inversion mechanism is used to reduce the warping of BC solar cells. The solar cells are located on a support platform, with the length direction of the solar cells being a first direction. The stacking welding machine inversion mechanism is located directly above the solar cells and includes a pressure needle, a suction nozzle, a lifting plate, and a drive mechanism. The bottom of the lifting plate is provided with multiple pressure needles and suction nozzles. The output end of the drive mechanism is connected to the lifting plate and is used to drive the pressure needles and suction nozzles to move up and down. The pressure needle acts on the non-main grid dense area on a single battery cell to independently bend and shape each battery cell in the battery string entering the stacking process. The suction nozzle is positioned in the center of the battery cell and is used to adsorb and fix the battery cell after the bending is completed for welding operations.

[0008] Furthermore, the warped portions of two adjacent cells are connected by an inter-cell membrane cover. The two warped portions of each cell are half cells. Each inter-cell membrane is provided with at least two pressure pins, and the two pressure pins are symmetrically arranged along the first direction on both sides of the inter-cell membrane edge region.

[0009] Furthermore, the lifting plate has a plurality of pressure pin mounting holes, and the pressure pin is connected to the pressure pin mounting holes by a thread, which can adjust the height of the pressure pin itself.

[0010] Furthermore, the bottom of the pressure needle is provided with a pressing part, the bottom surface of the pressing part is a plane, and the height of the bottom surface of the pressing part is lower than the height of the bottom of the suction nozzle, and the height difference is 1 to 7 mm.

[0011] Furthermore, in the first direction, the distance between the center of the pressure needle and the short edge of the battery cell is 20-40 mm.

[0012] Furthermore, in the first direction, the distance between the pressure pin and the short edge of the battery cell is greater than 3.5 mm, in order to avoid edge stress concentration that could lead to microcracks in the battery cell.

[0013] Furthermore, the diameter of the pressure needle is ≤5mm.

[0014] The method of using the inverted mechanism of the lap welding machine includes the following steps: First pressure: The driving mechanism drives the pressure needle downward to contact the inter-sheet membrane and apply a preset pressure to achieve initial shaping; Lifting phase: The pressure needle retracts, releasing some of the elastic stress; Second press: The pressure needle descends again to the target warp position, completing the final inversion; Suction nozzle adsorption: After the reverse bending is stabilized, vacuum adsorption is initiated to fix the battery cell and enter the welding process.

[0015] Furthermore, the time interval between the first and second pressure is 0.5–2 seconds, allowing the solar cells to partially spring back, thereby improving inversion stability.

[0016] A photovoltaic module, manufactured by the method described above, comprises low-warpage BC cell strings or non-warpage cell strings formed by the inversion process of the inversion mechanism of the lamination machine, wherein the cell strings do not exhibit obvious edge warping before and after lamination, and no mechanical damage caused by the inversion process occurs.

[0017] Compared with the prior art, the beneficial effects of the present invention are: Compared to existing technologies, this solution places the pressure pins directly above the solar cells. Before the solar cell string enters the stacking machine, a drive mechanism drives the lifting plate and pressure pins downwards, causing the pressure pins to act on the non-busbar dense areas of the solar cell, achieving initial shaping and correction of the warped parts of the solar cell. This step is called bending. Then, the pressure pins are driven to rise and retract to continue bending the warped parts of the solar cell at least twice. This ensures that the warped parts at both ends of the solar cell are flattened, and all solar cells are evenly pressed, which can reduce the warp of the solar cell string and even eliminate the phenomenon of the solar cells warping at both ends. This makes the solar cell string flatter, thereby reducing or eliminating the problems of hidden cracks and broken cells in the production of solar cell strings, thus improving the yield and reliability of solar cell modules. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the recurve mechanism during bending in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the structure of the recurve mechanism after bending and recurving according to Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the structure of the recurving mechanism after bending and recurving according to Embodiment 2 of the present invention.

[0020] In the picture: 1-Lifting plate; 2-Pressure needle; 3-Interlayer film; 4-Battery cell; 5-Suction nozzle; 6-Pressure bonding part. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention 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 invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" 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 of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0028] This application relates to a shingling machine inversion mechanism for reducing BC cell warpage, particularly suitable for the shingling process of back-contact (BC) type solar cell modules. It is used to improve the cell string warpage problem caused by uneven thermal stress during welding and curing, thereby reducing the risk of microcracks and improving module yield and reliability.

[0029] Example 1 Reference Figure 1 and Figure 2 (A schematic diagram can be attached). In the BC battery module stacking process, the entire battery string is composed of multiple battery cells 4 arranged sequentially. Adjacent battery cells 4 are connected by solder ribbons, and an inter-cell film 3 is attached between the solder ribbons and the back of the battery. The inter-cell film 3 simultaneously covers two adjacent battery cells 4 and is symmetrically arranged about the gap between the cells to ensure a consistent front appearance. This solution takes a battery cell 4 with a size of 182.2mm × 96.25mm (based on a whole 182.2 × 192.5mm cut) as an example for specific explanation, as follows: Before the stacking process, the battery strings are pre-shaped using a recurving mechanism after entering the stacking machine. The battery cells 4 are arranged in an array along their length direction, with the length direction of the battery cells 4 as the first direction.

[0030] The anti-bending mechanism of the shingled welding machine provided in this embodiment includes a pressure needle 2, a suction nozzle 5, a lifting plate 1, and a driving mechanism. The pressure needle 2 is located above the area between two adjacent battery cells 4, that is, above the gap between cells, the position between cells, or the inter-cell film 3, and is used to apply downward pressure to form a local reverse bending (anti-bending) to counteract the forward warping problem.

[0031] Specifically, the center of the pressure needle 2 is located at the gap between the cells, allowing the pressure needle 2 to act on the inter-cell area when it presses down. The suction nozzle 5 is located in the center area of ​​each half-cell, used to pick up and position the cell 4 for welding. The bottom end of the suction nozzle 5 is a suction port, and the other end of the suction nozzle 5 is connected to a vacuum suction mechanism to provide negative pressure (the vacuum suction mechanism is a conventional technology and will not be described in detail). The bottom of the pressure needle 2 is provided with a pressing part 6. The pressing part 6 can be a buffer pressure head made of elastic material, or equipped with a pressure sensor and feedback control system (as an extension) to achieve precise control of the bending force. The pressing part 6 can also be a rigid sheet or plate structure with a flat bottom surface to flatten the warped part of the cell 4.

[0032] However, in practical applications, it was found that because the BC battery has a single-sided welded structure, during the welding heating and insulation adhesive curing process, the shrinkage of the weld strip and the volatilization of the adhesive layer generate asymmetric thermal stress, causing the battery cell 4 to warp upwards as a whole. Although the inter-cell inversion can adjust the deformation in the middle to some extent, since the edge battery cells 4 have no external support, when the pressure pin 2 acts on the middle inter-cell area, the first and last battery cells 4 warp upwards instead, causing the entire string to be suspended in an "arch" shape.

[0033] When the battery string enters the subsequent lamination or glass bonding process, the raised part is subjected to glass pressure, which can easily cause mechanical stress concentration at the edge of the battery cell or in the main grid area, resulting in microcracks or even cell breakage, significantly reducing the module yield.

[0034] Therefore, in this embodiment, the pressure pin 2 acts on the inter-cell position of the battery cell 4, which can partially alleviate the warping in the middle of the battery string, but the effect of controlling the deformation of the edge battery cell 4 is limited. Moreover, the reverse bending position directly acts on the inter-cell solder strip area, which may cause solder strip displacement or excessive local stress.

[0035] Example 2: Reference Figure 3 This embodiment provides a bending mechanism for a stacking welding machine, aiming to solve problems such as the lifting of the beginning and end of the battery string and the induction of microcracks by bending in the prior art, and to improve upon the solution in Embodiment 1. Its core lies in changing the bending action position from "between the cells" to "on the edge region of the cells", and by adjusting the number and position distribution of bending, more uniform stress compensation and higher stacking flatness can be achieved.

[0036] Specifically, in this embodiment, the battery cell 4 used is still a standard BC type battery with dimensions of 182.2mm × 192.5mm, so each half cell (half battery cell) is 96.25mm long. Before stacking, the entire string of batteries is arranged sequentially on the working platform (bearing platform), with the length direction of the battery cell 4 and the laying direction of the battery cell 4 being the first direction.

[0037] The inverted bending mechanism of the stacking welding machine is located directly above the battery cell 4, and includes a pressure pin 2, a suction nozzle 5, a lifting plate 1, and a drive mechanism. Multiple pressure needles 2 and suction nozzles 5 are provided at the bottom of the lifting plate 1. The output end of the drive mechanism is connected to the lifting plate 1 to drive the pressure needles 2 and suction nozzles 5 to move up and down. Among them, the pressure needle 2 can act on the non-main grid dense area on a single battery cell 4 under the drive of the drive mechanism, and is used to independently bend and shape each battery cell 4 in the battery string entering the stacking process. The suction nozzle 5 is positioned in the center of the battery cell 4 and is used to adsorb and fix the battery cell 4 after the bending is completed for welding operations.

[0038] It should be noted that "non-main busbar dense area" refers to the area on the surface of solar cell 4 where there are few or no main busbar lines. It is a spatial concept relative to "main busbar dense area"; mechanical contact (such as pressing down with pressure pin 2) in this area will not directly compress the conductive main busbar, fine busbar, or solder strip connection area, thereby reducing the risk of electrical short circuits, busbar breakage, microcracks, etc.

[0039] The warped portions of two adjacent battery cells 4 are covered by an interlayer membrane 3. The two warped portions of each battery cell 4 are half-cells. Each interlayer membrane 3 is equipped with at least two pressure pins 2, and the two pressure pins 2 are symmetrically arranged on both sides of the edge region of the interlayer membrane 3 along the first direction.

[0040] In one optional implementation, a plurality of mounting holes for pressure needles 2 are provided on the lifting plate 1. The mounting holes for pressure needles 2 are threaded holes, and the outer side wall of the pressure needle 2 is provided with an external thread. The pressure needle 2 is connected to the mounting holes for pressure needles 2 by threading. The height of the pressure needle 2 can be adjusted by turning the pressure needle 2, and the anti-bending height can be adjusted up and down according to the amount of downward pressure.

[0041] The bottom of the pressure needle 2 is provided with a pressing part 6. The bottom surface of the pressing part 6 is flat, and the height of the bottom surface of the pressing part 6 is lower than the bottom height of the nozzle 5, and the height difference is 1-7mm. The horizontal position of the pressure needle 2 is 1-7mm lower than the plane where the bottom end of the nozzle 5 is located, and the pressure needle 2 can be turned to adapt to the battery sheet 4 with different degrees of warping.

[0042] For the specific positioning parameters of a standard 182.2×192.5mm BC battery, in the first direction, the distance between the center of the pressure pin 2 and the short edge of the battery cell 4 is 20-40mm. In practice, the distance between the center of the pressure pin 2 and the short edge of the battery cell 4 (between cells) is 23-24mm. The distance between the pressure pin 2 and the short edge of the battery cell 4 is greater than 3.5mm to avoid edge stress concentration that could lead to microcracks in the battery cell 4.

[0043] Optionally, the diameter of the pressure needle 2 is ≤5mm.

[0044] In summary, the key improvements of the recurve mechanism in this embodiment compared to the technical solution of Embodiment 1 are as follows: 1. Adjusting the recurve position: The pressure pin 2 no longer acts on the solder strip area (inter-cell area) between adjacent solar cells 4, but is instead positioned within the edge area of ​​each solar cell 4 itself, pressing against the inter-cell film 3. This avoids direct contact with the solar cell 4, preventing damage. The pressure pin 2 is close to the short edge of the solar cell 4 but avoids the densely packed main busbar area. Preferably, the center of the pressure pin 2 is 23.0375mm from the short edge of the solar cell 4. This value is precisely set based on the main busbar arrangement (PT value) to ensure that the pressure pin 2 is positioned directly above the third main busbar, avoiding damage to the main busbar lines.

[0045] 2. Safety boundary design of pressure needle 2: The edge of the pressure pin 2 is more than 3.5 mm away from both the cut edge (short side) and the original edge (long side) of the battery cell 4 to prevent edge stress concentration.

[0046] 3. Increased number of recurves: Each half of the solar cell (i.e., one end of each solar cell 4) is equipped with two independent pressure pins 2, and the two pressure pins 2 are symmetrically arranged about the gap between the cells, acting on the edge areas on both sides of the solar cell 4 respectively to achieve bilateral synchronous inversion. Compared with the method in Embodiment 1 where every two solar cells 4 share one pressure point, this solution achieves full-coverage inversion control of "one cell with two points", significantly improving the deformation control accuracy.

[0047] 4. Dynamic adjustment of recurve height: The overall horizontal position of the recurve mechanism is 1-7mm lower than the working plane of the nozzle 5. The specific downward pressure can be automatically adjusted according to the initial warp of the battery cell 4 detected in real time. For example, for battery strings with an initial warp of more than 3mm, the recurve downward pressure is set to 5mm; for those with smaller warp, it can be set to 2mm to achieve flexible adaptation.

[0048] 5. Multi-stage recurve motion procedure: First stage: The recurve mechanism first gently presses the battery string to the target position to perform preliminary shaping and release some internal stress; Second stage: The drive mechanism briefly lifts to release instantaneous pressure; Third stage: Press down again to the final recurve position and maintain stability; At the same time, the suction nozzle 5 starts the suction action to firmly adsorb the battery cell 4 that has completed the recurve shaping, and then performs the welding strip welding.

[0049] In addition, the suction nozzle 5 is positioned in the center of each half-cell battery to ensure adsorption stability while avoiding interference with the pressure needle 2.

[0050] After the above-mentioned process, the entire battery string is in a good horizontal state before welding, with no tilting of the first and last battery cells and no suspended areas in the entire string. After welding, the overall flatness of the battery string is better than ±0.5mm / m, which is an improvement of more than 60% compared with the existing technology.

[0051] Experimental results show that, under the same lamination conditions, the incidence of microcracks is significantly reduced with the inverted curve mechanism of this embodiment, which significantly improves product reliability and photoelectric conversion efficiency.

[0052] Meanwhile, because the curved area avoids the solder strip and the core area of ​​the main busbar, the pressure on the electrical connection structure is reduced, further improving the consistency of welding quality. In addition, since the edge cells 4 are effectively flattened, the inter-string edge distance can be appropriately shortened, which indirectly increases the light-receiving area of ​​the module and helps to improve the output power per unit area.

[0053] In summary, this embodiment fundamentally solves the technical problem of the beginning and end of BC battery strings lifting during the stacking process by shifting the point of inversion application from "between cells" to "on-chip edge" and combining it with a dual pressure pin layout and a multi-level inversion control strategy. This solution not only improves the geometric flatness of the battery strings but also reduces the risk of mechanical damage during production, demonstrating promising prospects for industrial application.

[0054] It should be noted that those skilled in the art can make adaptive adjustments to the position of the pressure needle 2, the downward pressure, and the timing of the action based on factors such as the actual battery size, main grid layout, and material characteristics, all of which fall within the scope of protection of this application.

[0055] Example 3 The method of using the inverted mechanism of the lap welding machine includes the following steps: First pressure: The driving mechanism drives the pressure needle 2 to descend and contact the inter-sheet membrane 3 and apply a preset pressure to achieve initial shaping; Lifting phase: The pressure needle 2 retracts, releasing some of the elastic stress; Second press: The pressure needle 2 descends again to the target warp position, completing the final recurve; Suction nozzle 5 adsorption: After the reverse bending is stabilized, vacuum adsorption is started to fix the battery cell 4 and enter the welding process.

[0056] In one optional implementation, the time interval between the first and second pressure is 0.5–2 seconds, allowing the battery cell 4 to partially spring back, thereby improving the inversion stability.

[0057] Note: The action of pressing the pressure needle 2 down on the warped part of the battery cell 4 is called bending. In this method of use, the number of bending operations is not limited to two, and the number of bending operations can be increased to more than two depending on the actual situation to fully ensure the bending effect.

[0058] Example 4 A photovoltaic module, manufactured using the aforementioned inversion mechanism of a shingling machine, comprises low-warpage BC cell strings or warpage-free cell strings formed by the inversion process of the shingling machine. The cell strings exhibit no significant edge warping before or after lamination, and no mechanical damage caused by the inversion process occurs. This inversion mechanism is applicable to shingling equipment for back-contact (BC) type solar cell modules, particularly for shaping cell strings with interlayer film 3 strips to prevent microcracks or breakage caused by warpage during lamination or glass bonding.

[0059] The beneficial effects of the technical solution of the present invention are: I. Significantly reduces battery string warpage and improves overall string levelness Solving the problem of warping at the beginning and end of the battery cell 4: This solution adjusts the anti-curving position to the periphery of each battery cell 4 (on the cell surface), and in particular, by applying downward pressure to the edge battery cell 4, the warping tendency is effectively suppressed.

[0060] The entire string is in a more stable, horizontal state: The improved inversion mechanism keeps the entire battery string basically on a single plane during the stacking process, avoiding the phenomenon of some battery cells being suspended in the air, and greatly improving the physical stability before welding.

[0061] Technical benefits include: improved yield and consistency in subsequent welding, lamination and other processes, and reduced stress concentration caused by deformation.

[0062] II. Significantly reduce the risk of hidden cracks and fragmentation. Eliminate mechanical stress impact during lamination / glass bonding process: In traditional processes, due to the warping of the battery string, the warped cells 4 are forcibly flattened during lamination or glass bonding, creating localized high-stress areas that easily lead to microcracks (hidden cracks) or even breakage (fragmentation). This solution, through pre-shaping and on-chip anti-curvature control, ensures that the initial state of the battery string is close to an ideal plane, significantly reducing mechanical impact at this stage.

[0063] The recurve motion itself no longer induces hidden cracks: This solution uses two pressure pins 2 for each cell, distributed around the main grid area, resulting in a more uniform pressure distribution and avoiding sensitive solder strip areas, thereby preventing the cells from being directly crushed during the bending process 4.

[0064] Technical benefits include: improved component yield, reduced rework and scrap costs, and enhanced long-term product reliability (especially important for ultra-thin batteries with high power and thin-film trends).

[0065] III. Optimize the design of the inversion position and dimensions to achieve refined stress control. Precisely set the position of pressure pin 2 to match the main grid layout: The center of the pressure needle 2 is located on the third main grid and is 23.0375mm away from the short side (which can be finely adjusted according to the PT value) to ensure that the pressure is applied to the main grid area with high structural strength and to avoid damage to weak areas (such as areas without grid lines).

[0066] Safety boundary design prevents edge damage: The edge of the pressure needle 2 is more than 3.5mm away from the cut edge and the original edge of the battery cell 4. Combined with the 5mm diameter pressure head, it effectively avoids pressure concentration on the fragile edge area.

[0067] Adjustable recurve height (1–7mm lower than the nozzle): The horizontal position of the recurve can be dynamically adjusted according to the actual degree of warping of the battery cell 4, so as to achieve "recurve on demand", which ensures the shaping effect without excessive pressure.

[0068] Technical benefits: It has good process adaptability and compatibility, and is suitable for different batches and different warpage characteristics of solar cells, thereby improving the intelligence and flexible production capabilities of the equipment.

[0069] IV. Improve the quantity and distribution of inflections to enhance overall structural stability. Each solar cell 4 has two independent inflection points, which increases the controllable degrees of freedom of each solar cell 4, allowing each cell to be corrected independently and avoiding the accumulation of local deformation caused by cascading effects. Increasing the density of inflection points improves control precision, and the denser distribution of inflection points helps to form a continuous inverted curved surface, better offsetting the thermal stress asymmetry problem caused by single-sided welding of BC cells.

[0070] Technical benefits: Refined control improves the consistency and repeatability of the flatness of the entire string.

[0071] 5. Reduce the size of the curved area to protect key functional areas. The inversion area has been reduced from approximately 1 / 4 of the sheet width to approximately 1 / 8 of the sheet width, significantly reducing the space occupied. This allows the inversion action to avoid the solder strip bonding area and busbar welding area, preventing extrusion deformation or displacement of the already laid solder strips. It also avoids pressing on the inter-sheet membrane 3 and the solder strip connection area, as the presence of the inter-sheet membrane 3 already increases the risk of uneven thickness. If the inversion pressure head presses on this area, it can easily cause membrane strip displacement or solder strip detachment. The new solution avoids this risk by applying pressure to the non-soldering area on the sheet.

[0072] Technical benefits include: ensuring stable welding quality, preventing defects such as incomplete welding and misalignment, and extending the life of the mold / pressure head.

[0073] VI. Indirectly improve the photoelectric conversion efficiency and appearance quality of the components Increasing the effective light-receiving area, while not changing the physical dimensions of the solar cells, results in a flatter string, reducing shading and uneven encapsulation caused by warping, thus increasing the actual usable light-receiving area. Improving the consistency of the module's front appearance, BC modules emphasize a clean, grid-free front. Issues such as color differences and bubbles caused by microcracks or lamination abnormalities can affect the appearance quality. This solution indirectly ensures the visual consistency of high-end products by improving process stability.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bending mechanism for a shingling machine, used to reduce the warping of a BC solar cell (4), wherein the solar cell (4) is located on a support platform, the length direction of the solar cell (4) is a first direction, and the bending mechanism is positioned directly above the solar cell (4), characterized in that, It includes a pressure needle (2), a suction nozzle (5), a lifting plate (1), and a drive mechanism; The bottom of the lifting plate (1) is provided with multiple pressure needles (2) and suction nozzles (5). The output end of the driving mechanism is connected to the lifting plate (1) to drive the pressure needles (2) and suction nozzles (5) to move up and down. The pressure needle (2) acts on the non-main grid dense area on a single battery cell (4) to independently bend and shape each battery cell (4) in the battery string that enters the stacking process. The suction nozzle (5) is correspondingly disposed in the central area of ​​the battery cell (4) and is used to adsorb and fix the battery cell (4) after the recurving is completed for welding operation; The warped portions of two adjacent battery cells (4) are covered by a single interlayer membrane (3). The two warped portions of each battery cell (4) are half battery cells. Each interlayer membrane (3) is configured with at least two pressure pins (2), and the two pressure pins (2) are symmetrically arranged along the first direction on both sides of the edge region of the interlayer membrane (3).

2. The inverted bending mechanism of the lap welding machine according to claim 1, characterized in that, The lifting plate (1) has multiple mounting holes for pressure pins (2). The pressure pins (2) are connected to the mounting holes for pressure pins (2) by a thread, which can adjust the height of the pressure pins (2).

3. The inverted bending mechanism of the lap welding machine according to claim 2, characterized in that, The bottom of the pressure needle (2) is provided with a pressing part (6), the bottom surface of the pressing part (6) is a plane, and the bottom surface of the pressing part (6) is lower than the bottom height of the suction nozzle (5), and the height difference is 1 to 7 mm.

4. The inverted bending mechanism of the lap welding machine according to claim 1, characterized in that, In the first direction, the distance between the center of the pressure needle (2) and the short edge of the battery cell (4) is 20-40 mm.

5. The inverted bending mechanism of the lap welding machine according to claim 4, characterized in that, In the first direction, the distance between the pressure pin (2) and the short edge of the battery cell (4) is greater than 3.5 mm, in order to avoid edge stress concentration that could cause microcracks in the battery cell (4).

6. The inverted bending mechanism of the lap welding machine according to claim 1, characterized in that, The diameter of the pressure needle (2) is ≤5mm.

7. A method of using the inverted mechanism of the lap welding machine according to any one of claims 1 to 6, characterized in that, Includes the following steps: First pressing: The driving mechanism drives the pressure needle (2) to descend and contact the inter-sheet membrane (3) and apply a preset pressure to achieve preliminary shaping; Lifting stage: The pressure needle (2) retracts, releasing some of the elastic stress; Second press: The pressure needle (2) moves down again to the target warp position to complete the final recurve; Suction nozzle (5) adsorption: After the reverse bending is stabilized, vacuum adsorption is started to fix the battery cell (4) and enter the welding process.

8. The method of use according to claim 7, characterized in that, The time interval between the first and second pressure is 0.5–2 seconds, allowing the battery cell (4) to partially rebound in order to improve the inversion stability.

9. A photovoltaic module, characterized in that, Manufactured by the method of use as described in claim 7 or 8, comprising low-warpage BC battery strings or non-warpage battery strings formed after being reverse-bent by the reverse-bent mechanism of the lamination machine, wherein the battery strings do not exhibit obvious edge warping before and after lamination, and no mechanical damage caused by the reverse-bent process occurs.

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