Method of manufacturing a photovoltaic laminate, laminate, photovoltaic module and method of reworking a photovoltaic laminate

Abstract

The application discloses the technical field of photovoltaic, and discloses a preparation method of a photovoltaic laminated component, the laminated component, a photovoltaic module and a repair method of the photovoltaic laminated component.The preparation method of the photovoltaic laminated component comprises the following steps: placing a plurality of cell pieces on a combination of a front plate and a front adhesive film; pre-fixing a solder strip on the cell pieces, and coating solder between the cell pieces and the solder strip; placing a back adhesive film and a back plate on the solder strip to form a laminated component; laminating the laminated component to form a semi-finished laminated component; and laser welding the position of the solder on the semi-finished laminated component to weld the solder strip and the cell pieces together to form the laminated component.The application welds after lamination, and can reduce the problems of virtual welding or disconnection in the process of welding first and then laminating, compared with the existing high-temperature welding and low-temperature welding.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a method for preparing a photovoltaic laminate, the laminate, a photovoltaic module, and a method for repairing the photovoltaic laminate. Background Technology

[0002] With the rapid development of the photovoltaic industry, the commonly used welding methods for bonding solder strips to the grid lines on solar cells mainly include high-temperature welding and low-temperature welding. High-temperature welding involves bonding the high-temperature solder strips to the grid lines using high-temperature welding techniques (such as infrared welding and laser welding) before lamination, followed by the stacking and lamination processes. Low-temperature welding involves pre-fixing the low-temperature solder strips to the grid lines of the solar cell, and then bonding them together during the lamination process using the lamination temperature. Regardless of whether it's high-temperature or low-temperature welding, the vacuum process during lamination can cause solder strip displacement, leading to incomplete soldering or detachment.

[0003] The information disclosed in the background section is only for enhancing the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] Based on this, a method for preparing a photovoltaic laminate, a laminate, a photovoltaic module, and a method for repairing a photovoltaic laminate are provided. After lamination, laser welding is used to weld the solder strip to the solar cell, reducing the problems of incomplete soldering and desoldering caused by vacuuming during the lamination process.

[0005] Therefore, in a first aspect, embodiments of this application provide a method for preparing a photovoltaic laminate, comprising: Multiple battery cells are placed on the assembly of the front panel and the front adhesive film; The solder ribbon is pre-fixed onto the battery cell, and solder is applied between the battery cell and the solder ribbon; An adhesive film and a backing plate are placed on the solder strip to form a laminated part; The laminated parts are laminated to form a semi-finished laminated part; Laser welding is performed on the areas of the semi-finished laminate where the solder is applied, welding the solder strip together with the battery cell to form a laminate.

[0006] In one embodiment, it further includes: Detect whether there are any poor solder joints in the laminated component; If the laminate has a poor weld position, the poor weld position is laser welded for repair.

[0007] In one embodiment, pre-fixing the solder strip onto the battery cell includes: The welding strip is pre-fixed to the battery cell by adhesive bonding; or... The welding strip and the battery cell are pre-fixed by a coating process, with a coating temperature of 115℃-120℃. The welding strip is pre-fixed to the battery cell by a snap-fit ​​method.

[0008] In one embodiment, the high-temperature welding strip is provided with multiple grooves.

[0009] In one embodiment, the laser power used in the laser welding is 25W-35W, the laser pulse frequency is 10Hz-50Hz, the welding speed is 0.5m / min-2m / min, and the welding spot diameter is 0.5mm-1mm.

[0010] In one embodiment, at least the front panel is made of special glass, the special glass having a softening temperature of 500°C or higher, and the light transmission wavelength range of the special glass being 380nm-560nm.

[0011] In one embodiment, the special glass is borosilicate glass or quartz glass.

[0012] In one embodiment, the thickness of the front panel ranges from 1.8 mm to 3.2 mm.

[0013] Secondly, embodiments of this application provide a laminate prepared using the photovoltaic laminate preparation method described in any of the preceding claims.

[0014] Thirdly, embodiments of this application provide a laminate and a frame surrounding the circumferential edge of the laminate, wherein the laminate employs the laminate described above.

[0015] Fourthly, embodiments of this application provide a method for repairing photovoltaic laminates, including: Inspect the laminated components for any areas with poor solder joints. If the laminate has a poor weld position, the poor weld position is laser welded for repair.

[0016] According to the photovoltaic laminate preparation method, laminate, photovoltaic module, and photovoltaic laminate repair method provided in the embodiments of this application, the photovoltaic laminate preparation method includes: placing multiple solar cells on a front panel and front encapsulant film assembly; pre-fixing solder ribbons to the solar cells and applying solder between the solar cells and solder ribbons; placing a back adhesive film and a back panel on the solder ribbons to form a laminate; laminating the laminate to form a semi-finished laminate; and laser welding the solder-coated areas of the semi-finished laminate to weld the solder ribbons and solar cells together to form the laminate. This application performs welding after lamination, which, compared to existing high-temperature welding and low-temperature welding, can reduce the problems of incomplete soldering or desoldering that occur during the process of welding before lamination. Attached Figure Description

[0017] Figure 1 A flowchart illustrating a method for fabricating a photovoltaic laminate according to an embodiment of this application is shown; Figure 2 This illustration shows a structural schematic diagram of a laminate provided in an embodiment of this application; Figure 3 This diagram illustrates a structure of a laminate exhibiting poor solder joints, as provided in an embodiment of this application. Figure 4 This illustration shows a structural diagram of a laminate after repair, according to an embodiment of this application. Figure 5 The image shows an EL diagram of a prior art photovoltaic module that has not been repaired and has not undergone TC200 testing. Figure 6 An EL image showing a laminated component of the prior art after laser welding repair is displayed. Figure 7 This image shows an EL view of a laminate provided in an embodiment of this application; Figure 8 Show Figure 7 The image shown is an EL observation diagram of the laminate after the TC200 reliability test.

[0018] Explanation of reference numerals in the attached figures: 1. Front panel; 2. Front adhesive film; 3. Battery cell; 4. Solder strip; 5. Back adhesive film; 6. Back panel; 7. Laminated component. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0021] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0022] Reference Figures 1-4 , Figure 1 This document shows a flowchart illustrating a method for fabricating a photovoltaic laminate according to an embodiment of this application. Figure 2 This diagram illustrates the structure of a laminate provided in an embodiment of this application. Figure 3 This diagram illustrates a structure with poor solder joints in a laminate provided in an embodiment of this application. Figure 4 This diagram illustrates the structure of a laminated component after repair, as provided in an embodiment of this application.

[0023] This application provides a method for preparing a photovoltaic laminate, comprising: S1. Place multiple battery cells 3 on the assembly of front panel 1 and front adhesive film 2; S2. Pre-fix the welding ribbon 4 onto the battery cell 3, and apply solder between the battery cell 3 and the welding ribbon 4; S3. Place the adhesive film 5 and the backing plate 6 on the welding strip 4 to form a laminated part; S4. Laminate the laminated parts to form a semi-finished laminated part; S5. Laser welding is performed on the coated solder positions of the semi-finished laminate to form laminate 7.

[0024] It should be understood that, as an example, this application first lays a pre-coating film 2 on one side of the front panel 1. The pre-coating film 2 is made of EPE (expandable polyethylene) and weighs 400g. Multiple battery cells 3 are then laid sequentially on the pre-coating film 2. The battery cells 3 are N-type battery cells. The solder ribbon 4 is then pre-fixed to the battery cells 3 to prevent misalignment after lamination. The solder ribbon 4 can be a high-temperature solder ribbon, which improves resistance to hot spot risk compared to a low-temperature solder ribbon. The material can be a single metal or an alloy. As an example, the diameter of the solder ribbon 4 can be 0.22mm, and the coating thickness can be 15µm. Solder is placed between the solder ribbon 4 and the battery cells 3. The solder is solder paste, and the solder paste material is 63% Sn and 37% Pb. Then, an adhesive film 5 and a backing plate 6 are laid on the solder ribbon 4. The adhesive film 5 is made of EVA material (ethylene-vinyl acetate copolymer), and its weight is 400g. Lamination is then performed. After lamination, a semi-finished laminate is formed. This semi-finished laminate is then laser-welded. The laser irradiates the front plate 1, thereby welding the solder ribbon 4 to the grid lines of the battery cell 3. After welding, a laminate 7 is formed. (Refer to...) Figure 7 As shown, Figure 7 The image shows an EL observation of a laminate provided in an embodiment of this application. The laminate 7, prepared according to the photovoltaic laminate preparation scheme provided in this application, shows virtually no cold solder joints or desoldering. The laminate 7 can then be trimmed, fitted with a junction box, fixed, cleaned, tested, and packaged to form a photovoltaic module. If the laminate 7 has cold solder joints, it can be re-welded using a laser from the front panel 1 to repair the cold solder joints. After successful repair, the laminate 7 can be trimmed, fitted with a junction box, fixed, cleaned, tested, and packaged to form a photovoltaic module.

[0025] Compared to existing high-temperature and low-temperature welding, this application uses laser welding to weld the solder strip to the solar cell after lamination, which can reduce displacement during the lamination process and reduce the occurrence of incomplete welds and desoldering.

[0026] The method for preparing a photovoltaic laminate provided in this application further includes: S6. Check if there are any poor welds in the laminate 7; S7. If there are poor welds in the laminate 7, laser welding will be performed on the poor welds for repair.

[0027] In some optional embodiments, pre-fixing the solder ribbon 4 to the battery cell 3 and applying solder between the battery cell 3 and the solder ribbon 4 includes pre-fixing the solder ribbon 4 and the battery cell 3 by adhesive bonding. For example, applying a dotted adhesive, such as UV adhesive or hot melt adhesive, between the solder ribbon 4 and the battery cell 3, and curing the entire solder ribbon 4 onto the battery cell 3 using a UV lamp, thereby achieving pre-fixation between the solder ribbon 4 and the battery cell 3.

[0028] In some optional embodiments, the solder ribbon 4 and the battery cell 3 are pre-fixed by a coating process. The solder ribbon 4 and the battery cell 3 are fixed by the hot melt bonding and pressure of the encapsulation material (EVA / POE film). The coating temperature is 115℃-120℃, and the coating temperature can be 115℃, 116℃, 117℃, 118℃, 119℃ or 120℃, thereby achieving the pre-fixation between the solder ribbon 4 and the battery cell 3.

[0029] In some optional embodiments, the pre-fixation of the solder ribbon 4 and the battery cell 3 includes: the solder ribbon 4 and the battery cell 3 are pre-fixed by engaging. One of the solder ribbon 4 and the battery cell 3 is provided with a groove, and the other is provided with a protrusion; the engagement of the groove and the protrusion can pre-fix the solder ribbon 4 and the battery cell 3.

[0030] In one example, the solder strip 4 is provided with multiple grooves, which are used to achieve pre-fixation of the solder strip 4 and the battery cell.

[0031] This application achieves welding by laser welding after lamination, which can accurately identify the welding point and use a laser beam with precisely controllable energy to locally heat the welding area, thus ensuring that the welding material does not damage the surrounding laminated components.

[0032] In some optional embodiments, in the step of laser welding the solder-coated areas of the semi-finished laminate to form the laminate 7 and / or in the step of laser welding the cold solder joints for rework, the laser power used during laser welding is 25W-35W. The laser power can be 25W, 26W, 27W, 28W, 29W, 30W, 31W, 32W, 33W, 34W, or 35W, and this application does not impose any limitation. When the laser power is below 25W, the welding strength is insufficient, resulting in poor performance and a high risk of cold solder joints. When the laser power is above 25W, it can easily damage the laminate 7.

[0033] In some optional embodiments, the laser pulse frequency is maintained between 10Hz and 50Hz, and the laser pulse frequency is maintained at 10Hz, 20Hz, 30Hz, 40Hz, 50Hz, etc., which is not limited in this application. When the laser pulse frequency is higher than 50Hz, the excessively high frequency will lead to low pulse energy, resulting in welding failure. When the laser pulse frequency is lower than 10Hz, it will lead to discontinuous energy output, resulting in poor continuity of the welding point, risk of "weld breakage", concentrated local heat input, and increased risk of cell damage.

[0034] In some optional embodiments, the welding speed is 0.5m / min-2m / min. The welding speed can be 0.5m / min, 1m / min, 1.5m / min, 2m / min, etc. When the welding speed is lower than 0.5m / min, the welding speed is slow and excessive heat input will burn through the workpiece. When the welding speed is higher than 2m / min, the welding speed is too fast and the component cannot be welded.

[0035] In some optional embodiments, the welding spot diameter is 0.5mm-1mm, and the welding spot diameter can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, or 1mm. When the welding spot diameter is 0.5mm-1mm, the weld energy density is high and the welding effect is the best.

[0036] In some optional embodiments, at least the front panel 1 is made of special glass with a softening temperature of 500°C or higher and a light transmission wavelength range of 380nm-560nm. The front panel 1 is subjected to a temperature of 500°C or higher to avoid damage to the front panel 1 during laser welding. The light transmission wavelength of the front panel 1 is 380nm-560nm to facilitate the welding of green light, ultraviolet light, etc., in the 380nm-560nm range through the welding ribbon 4 and the grid lines of the battery cell 3.

[0037] The material of the back panel 6 can be either glass or plastic; this application does not impose any restrictions.

[0038] In some optional embodiments, the special glass is either borosilicate glass or quartz glass. That is, the front panel 1 can be either borosilicate glass or quartz glass.

[0039] In some optional embodiments, the thickness of the front plate 1 ranges from 1.8mm to 3.2mm. The thickness of the front plate 1 can be 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3.0mm, or 3.2mm, etc., and this application does not impose any limitation. When the thickness of the front plate 1 is less than 1.8mm, it is easy to damage the front plate 1 during welding. When the thickness of the front plate 1 is greater than 3.2mm, it is easy to experience incomplete soldering, resulting in poor welding performance.

[0040] In some optional embodiments, the laminate 7 after laser welding is tested for whether there is a cold solder joint, wherein the detection method is electroluminescence inspection (EL observation). This application can detect whether there is a cold solder joint in the laminate 7 through EL observation, and can accurately observe the location of the cold solder joint, marking the defect location of the laminate 7 for later laser repair.

[0041] The present application will be further described below through specific embodiments.

[0042] Example: S1. Lay a front adhesive film 2 on the front panel 1. The front panel 1 is made of special glass with a thickness of 2.0mm quartz glass, and the front adhesive film 2 is made of EPE (400g). Place multiple battery cells 3 on the assembly of the front panel 1 and the front adhesive film 2. S2. Pre-fix the solder ribbon 4 onto the battery cell 3 by snap-fitting, and apply solder paste between the battery cell 3 and the solder ribbon 4. S3. Place the adhesive film 5 and the backing plate 6 on the solder strip 4. The adhesive film 5 is made of EVA (400g) and the backing plate 6 is made of 2.0mm non-porcelain white glass to form a laminate. S4. Laminate the laminated parts to form a semi-finished laminated part; S5. Laser welding is performed on the position of the solder coating on the semi-finished laminate to form laminate 7. The laser power used for welding is 30W, the laser pulse frequency is maintained at 30Hz, the welding speed is 1m / min, and the welding spot diameter is 0.8mm. S6. Observe the laminate 7 after laser welding to see if there is any cold weld. If there is no cold weld, the welding is complete. S7. If the laminate 7 has a poor weld, select the laminate 7 with the poor weld and then perform laser welding again on the poor weld location for repair. S8. After welding, the laminate 7 is trimmed, fitted with a junction box, fixed, cleaned, tested, and packaged.

[0043] Reference Figure 7 and Figure 8 , Figure 7 The image shows an EL observation of the laminate prepared by the photovoltaic laminate preparation method of the present application embodiment. It can be seen that the EL test of the laminate prepared by the photovoltaic laminate preparation method provided in the present application embodiment did not reveal any desoldering or cold solder joints. Figure 8 Show Figure 7 The EL observation image shown shows the laminate after undergoing the TC200 reliability test (TC200 typically refers to the 200-cycle thermal cycle reliability test for photovoltaic modules, based on IEC 61215-10.11 and IEC 61730-MST51, used to verify the structural and electrical stability of the module under extreme temperature alternation, and to accelerate the exposure of thermal matching defects and potential failures). It can be seen that after the TC200 test, the laminate did not exhibit any desoldering or cold solder joints. The power loss after the TC200 test was less than 1%, indicating that the laminate's performance was stable.

[0044] This application also includes a laminate, which is manufactured using the photovoltaic laminate manufacturing method described in any of the preceding claims. Compared to existing high-temperature and low-temperature welding methods, the laminate of this application reduces the occurrence of incomplete solder joints and desoldering. In the event of an incomplete solder joint, the laminate 7 does not need to be disassembled and can be directly repaired using laser technology. Therefore, repair is simple, reducing waste of the laminate 7 and lowering battery production costs. Compared to existing low-temperature welding laminates (where low-temperature solder strips are fixed to the battery cells using tape or coating technology, and then the low-temperature solder strips are welded to the grid lines at high temperatures during the lamination process), this application uses solder strip 4, and the laminate will not produce hot spots.

[0045] This application also includes a photovoltaic module, including a laminate 7 and a frame surrounding the circumferential edge of the laminate 7, the laminate 7 being the laminate 7 described above.

[0046] This application also provides a method for repairing photovoltaic laminates, including detecting whether there are any cold solder joints in the laminated parts; if there are cold solder joints in the laminated parts, then performing laser welding on the cold solder joints for repair.

[0047] Reference Figure 5 , Figure 6 , Figure 5 This shows that existing photovoltaic modules do not have repaired EL diagrams that have not undergone TC200 testing. Figure 6 Showing will Figure 5 The image shown is an EL observation of the laminated component after repair. It can be seen that laser welding can repair incomplete or detached solder joints. Figure 5 The photovoltaic modules shown exhibiting poor soldering underwent TC200 reliability testing and were then subjected to further testing. Figure 6 The photovoltaic modules shown were compared using the TC200 reliability test after being repaired. The experiment was repeated three times. The power loss (PL) of the photovoltaic modules with poor soldering after the TC200 reliability test was 3.95%, 4.05%, and 4.59%, respectively. The power loss (PL) of the repaired photovoltaic modules after the TC200 reliability test was 0.95%, 0.89%, and 0.97%, respectively. Therefore, laser repair can greatly reduce power loss.

[0048] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0049] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a photovoltaic laminate, characterized in that, include: Multiple battery cells (3) are placed on the assembly of the front panel (1) and the front adhesive film (2); The solder ribbon (4) is pre-fixed onto the battery cell (3), and solder is applied between the battery cell (3) and the solder ribbon (4); An adhesive film (5) and a backing plate (6) are placed on the welding strip (4) to form a laminate; The laminated parts are laminated to form a semi-finished laminated part; Laser welding is performed on the position of the semi-finished laminate where the solder is coated, and the solder strip (4) is welded together with the battery cell (3) to form a laminate (7).

2. The method for preparing a photovoltaic laminate according to claim 1, characterized in that, Also includes: Check whether there are any poor solder joints in the laminate (7); If the laminate (7) has a poor weld position, then the poor weld position is laser welded for repair.

3. The method for preparing a photovoltaic laminate according to claim 1, characterized in that, The step of pre-fixing the welding strip (4) onto the battery cell (3) includes: The welding strip (4) is pre-fixed to the battery cell (3) by adhesive bonding; or, The welding strip (4) and the battery cell (3) are pre-fixed by a coating process, with a coating temperature of 115℃-120℃; The welding strip (4) and the battery cell (3) are pre-fixed by engaging.

4. The method for preparing a photovoltaic laminate according to claim 1 or 2, characterized in that, The laser power used in the laser welding is 25W-35W, the laser pulse frequency is 10Hz-50Hz, the welding speed is 0.5m / min-2m / min, and the welding spot diameter is 0.5mm-1mm.

5. The method for preparing a photovoltaic laminate according to claim 1, characterized in that, At least the front panel (1) is made of special glass, the softening temperature of the special glass is above 500°C, and the light transmission wavelength range of the special glass is 380nm-560nm.

6. The method for preparing a photovoltaic laminate according to claim 5, characterized in that, The special glass is borosilicate glass or quartz glass.

7. The method for preparing a photovoltaic laminate according to claim 1, characterized in that, The thickness of the front plate (1) ranges from 1.8 mm to 3.2 mm.

8. A laminate, characterized in that, It is prepared by the method for preparing photovoltaic laminates as described in any one of claims 1-7.

9. A photovoltaic module, characterized in that, It includes a laminate and a frame surrounding the circumferential edge of the laminate, the laminate being the laminate of claim 8.

10. A method for repairing photovoltaic laminates, characterized in that, include: Inspect the laminated components for any areas with poor solder joints. If the laminate has a poor weld position, the poor weld position is laser welded for repair.

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