A method and system for repairing a photovoltaic module cold weld

Abstract

The application provides a method and system for repairing virtual welding of a photovoltaic module, and specifically comprises the following steps: S1: after n cell pieces are series-welded to obtain a cell string, and before m cell strings are laminated and laid, virtual welding detection is performed on the cell string to obtain position information of all virtual welding points on the n cell pieces in the cell string; or after m*n cell pieces are arranged according to a module layout requirement to form a conductive connection structure, and before m cell strings are laminated and laid, virtual welding detection is performed on the m*n cell pieces in the m cell strings to obtain position information of all virtual welding points of the m*n cell pieces; S2: before the m cell strings are laminated and laid, all virtual welding points in the cell string are repaired, and all virtual welding points in the m*n cell pieces are repaired, including repairing each virtual welding point when laser scanning is performed while a reverse voltage is applied, so that contact loss caused in the welding process is repaired, and power loss of the finally prepared photovoltaic module is effectively reduced.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic module manufacturing technology, specifically, it relates to a method and system for repairing poor solder joints in photovoltaic modules. Background Technology

[0002] Crystalline silicon solar cells typically employ conductive paste printing combined with high-temperature sintering to fabricate metallized electrodes (i.e., metal grid lines) on the front and back sides of a silicon wafer. This creates a tight and efficient ohmic contact between the metallized electrodes and the solar cell, allowing photogenerated carriers to be extracted from the cell.

[0003] After metal grid lines are fabricated on the solar cells, adjacent cells need to be wired together using solder ribbons under high-temperature conditions to achieve electrical connection. However, contact loss can easily occur during high-temperature wired wired wired wired wired wired wired wired wired wired wired wired wires. Specifically, the instantaneous peak operating temperature of wired wired wired wired wires disrupts the stable silver-silicon contact structure, resulting in a decrease in effective contact area, increased instability of the contact structure, and a reduction in overall contact performance.

[0004] Especially during the metallization process, laser-induced sintering technology is often used to improve the metal-semiconductor contact performance. To adapt to laser-induced sintering, the conductive paste used in the process of preparing metallized electrodes on the front and back sides of the silicon wafer is more sensitive to the welding temperature, resulting in significant contact loss during the solder ribbon welding process. This leads to a large difference between the actual power and the theoretical power of the final photovoltaic module.

[0005] Currently, the repair of faulty solder joints involves removing the affected cell from the battery string, replacing it with a new cell, and then re-soldering it. This destructive method of repairing battery strings results in frequent movement of the strings, which may lead to more defects in the appearance of the cells or other problems. Summary of the Invention

[0006] In view of this, this application provides a method and system for repairing poor solder joints in photovoltaic modules. This method does not require damaging the battery string. It uses a poor solder joint detection module to detect poor solder joints, then uses a power module to apply a reverse voltage to the poor solder joints, and uses a laser processing module to perform laser scanning on the poor solder joints. This allows the poor solder joints to be repaired while the reverse voltage is applied and the laser scanning is performed, thereby reducing the power loss of the photovoltaic modules.

[0007] This application provides a method for repairing poor solder joints in photovoltaic modules, wherein the photovoltaic module comprises m cell strings, and each cell string comprises n cells connected in series, comprising the following steps:

[0008] S1: After connecting n solar cells together to form a solar cell string, and before laminating the m solar cell strings, perform a cold solder joint detection on the solar cell strings to obtain the location information of all cold solder joints on the n solar cells in the solar cell string; or after forming a conductive connection structure of m×n solar cells according to the module layout requirements, and before laminating the m solar cell strings, perform a cold solder joint detection on the m×n solar cells in the m solar cell strings to obtain the location information of all cold solder joints on the m×n solar cells;

[0009] S2: Before laminating m battery strings, all the faulty solder joints in the battery strings are repaired. The repair of all faulty solder joints in m×n battery cells includes repairing each faulty solder joint when laser scanning is performed while applying reverse voltage.

[0010] Preferably, during repair, a reverse voltage is applied near the solder joint to cause the solder joint to be subjected to a reverse voltage, and the solder joint is laser-scanned to repair the solder joint.

[0011] Preferably, the vertical distance between the malfunctioning solder joint and the location where the reverse voltage is applied is less than or equal to 30 cm.

[0012] Preferably, when there are two or more poor solder joints on the solar cell, when a reverse voltage is applied near one of the poor solder joints, the poor solder joints with a vertical distance of less than or equal to 30 cm from the position where the reverse voltage is applied are repaired simultaneously; for the poor solder joints on the solar cell with a vertical distance of more than 30 cm from the position where the reverse voltage was first applied, a reverse voltage is applied again at a position with a vertical distance of less than or equal to 30 cm from the poor solder joint and laser scanning is used to repair them, until all the poor solder joints on the solar cell are repaired.

[0013] Preferably, when a single cell has two or more faulty solder joints, a reverse voltage is applied to the cell once or multiple times and a laser scan is performed to repair all the faulty solder joints on the single cell.

[0014] Preferably, the method for detecting cold solder joints is one or more of EL detection, PL detection, or infrared thermal imaging detection.

[0015] Preferably, the reverse voltage applied to each of the aforementioned dummy solder joints does not exceed 30V.

[0016] Preferably, the reverse voltage applied to each of the aforementioned dummy solder joints does not exceed 20V.

[0017] Preferably, when performing laser scanning on the malfunctioning solder joint, the laser power applied to the malfunctioning solder joint is 1 to 1000 W.

[0018] Preferably, when performing laser scanning on the malfunctioning solder joint, the laser power applied to the malfunctioning solder joint is 15 to 300W.

[0019] This application also provides a system for repairing poor solder joints in photovoltaic modules, including a poor solder joint detection module, a power supply module, and a laser processing module. The poor solder joint detection module performs poor solder joint detection on all cell strings obtained by string welding or all cell strings of whole-plate welding, and obtains the position information of all poor solder joints on n cells in the cell string or the position information of all poor solder joints on m×n cells. The power supply module is used to apply reverse voltage to the poor solder joints, and the laser processing module is used to perform laser scanning on the poor solder joints.

[0020] Each faulty solder joint was repaired during the time period when the power supply module applied a reverse voltage to it and the laser processing module performed a laser scan on it.

[0021] Preferably, the power module includes a power supply unit and a probe unit. The power supply unit is electrically connected to the probe unit. When a reverse voltage is applied to the dummy solder joint, the probe array of the probe unit presses onto the solder strip on the battery cell near the dummy solder joint.

[0022] Preferably, when a reverse voltage is applied to the dummy solder joint, the vertical distance between the position of the probe array of the probe unit pressed on the solder strip on the battery cell and the dummy solder joint is less than or equal to 30 cm.

[0023] Preferably, when a single cell has two or more faulty solder joints, the probe array of the probe unit is pressed onto the solder strip on the cell one or more times to apply reverse voltage to the cell one or more times, and the cell is laser-scanned by a laser processing module to repair all the faulty solder joints on the single cell.

[0024] Preferably, the cold solder joint detection module is one or more of an EL detector, a PL detector, and / or an infrared thermal imaging detector.

[0025] The beneficial effects of this application are as follows: After connecting n solar cells together to form a solar cell string, and before laminating m solar cell strings, a faulty solder joint detection is performed on the solar cell strings to obtain the location information of all faulty solder joints on the n solar cells in the solar cell string. Alternatively, after forming a conductive connection structure of m×n solar cells according to the module layout requirements, and before laminating m solar cell strings, a faulty solder joint detection is performed on the m×n solar cells to obtain the location information of all faulty solder joints on the m×n solar cells. Then, before laminating m solar cell strings, all faulty solder joints in the solar cell strings are repaired. The repair of all faulty solder joints in the m×n solar cells includes repairing each faulty solder joint while applying reverse voltage and performing laser scanning. This effectively reduces the power loss of the final photovoltaic module, making the actual module power close to the theoretical value. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] The structures, proportions, sizes, etc., shown in the accompanying drawings 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 implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0028] Figure 1 This is a schematic diagram showing the distribution of faulty solder joints on each cell in a battery string.

[0029] Figure 2 This is a schematic diagram of one scenario where two faulty solder joints exist on a single solar cell.

[0030] Figure 3 Another schematic diagram showing two faulty solder joints on a single solar cell;

[0031] Figure 4 A schematic diagram showing that both the power supply module and the laser processing module are located at the welding device;

[0032] Figure 5 A schematic diagram showing a structure where both the power supply module and the laser processing module are located at the conveyor module;

[0033] Figure 6 This is a schematic diagram showing a structure where both the power supply module and the laser processing module are located at the lamination device.

[0034] In the diagram: 1-Welding device; 2-Lamination device; 3-Conveying module; 4-Power supply module; 41-Probe array; 5-Laser processing module; 6-Dummy solder joint. Detailed Implementation

[0035] The embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0036] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] refer to Figure 1-6 In the manufacturing process of photovoltaic modules, n solar cells are welded together by welding device 1, forming a cell string by connecting them in series. After m cell strings are arranged into a conductive connection structure according to the module layout requirements, they are conveyed to laminating device 2 via conveying module 3. Lamination is then performed in laminating device 2 to obtain a photovoltaic module. It is understandable that the laminated photovoltaic module is not a finished product; it still needs to undergo steps such as framing and welding of junction boxes to obtain the final finished photovoltaic module.

[0038] After forming a conductive connection structure by arranging m battery strings according to the module layout requirements, and before lamination, a lamination process is performed. The layers are laid from bottom to top as follows: glass, EVA, battery (m battery strings forming the conductive connection structure), EVA, and backsheet. Then, the photovoltaic module is obtained by lamination.

[0039] The values ​​of m and n can vary depending on the design of the photovoltaic module. This application does not impose specific limitations on the values ​​of m and n. For example, for a photovoltaic module containing 36 cells, m = 6 and n = 6 can be set. For another example, for a photovoltaic module containing 144 cells, m = 6 and n = 24 can be set.

[0040] This application provides a system for repairing cold solder joints in photovoltaic modules, specifically including the following steps:

[0041] S1: After n battery cells are connected together by welding device 1 to form a battery string, and before the m battery strings are laminated, the battery strings are inspected for poor solder joints by a poor solder joint detection module (not shown in the figure) to obtain the location information of all poor solder joints 6 on the n battery cells in the battery string; or after m×n battery cells are arranged into a conductive connection structure according to the module layout requirements, and before the m battery strings are laminated, the m×n battery cells in the m battery strings are inspected for poor solder joints to obtain the location information of all poor solder joints 6 on the m×n battery cells.

[0042] S2: Before laminating m battery strings, all the faulty solder joints 6 in the battery strings are repaired. During the repair, a reverse voltage is applied to the faulty solder joints 6 through the power module 4, and the faulty solder joints 6 are laser scanned by the laser processing module 5. The repair of all faulty solder joints 6 in m×n battery cells includes the repair of each faulty solder joint 6 when the power module 4 applies a reverse voltage to it and the laser processing module 5 laser scans it.

[0043] The cold solder joint detection module can be one or more of an EL (Electroluminescent) detector, a PL (Photoluminescence) detector, or an infrared thermal imager. For example, an EL detector can be used to perform EL detection on a battery string or m×n battery cells forming a conductive connection structure to obtain the location information of all cold solder joints 6 on the n battery cells in the battery string; or a PL detector can be used to perform PL detection on a battery string or m×n battery cells forming a conductive connection structure to obtain the location information of all cold solder joints 6 on the n battery cells in the battery string; or an infrared thermal imager can be used to perform infrared thermal imaging detection on a battery string or m×n battery cells forming a conductive connection structure to obtain the location information of all cold solder joints 6 on the n battery cells in the battery string. The process of performing EL detection, PL detection, or infrared thermal imaging detection on the battery cells is existing technology and will not be described in detail here.

[0044] In this embodiment, all the faulty solder joints 6 on the n cells in the battery string can be detected by the faulty solder joint detection module, and then each faulty solder joint 6 on the n cells can be repaired. Alternatively, all the faulty solder joints 6 on one cell in the battery string can be detected by the faulty solder joint detection module, and then the faulty solder joints 6 on that cell can be repaired. Then, the faulty solder joint detection module can be used to detect all the faulty solder joints 6 on the other cell in the battery string, and then the faulty solder joints 6 on that cell can be repaired, until all the faulty solder joints 6 on the n cells in the battery string have been detected and repaired. To improve efficiency, this embodiment preferably detects all the faulty solder joints 6 on the n cells in the battery string before repairing each faulty solder joint 6.

[0045] In this embodiment, typically all the faulty solder joints 6 in one battery string are detected and repaired before the faulty solder joints 6 in another battery string are detected and repaired, until all the faulty solder joints 6 in m battery strings are repaired.

[0046] In another embodiment, after the m×n solar cells are arranged into a conductive connection structure according to the module layout requirements, and before the m solar cell strings are laminated, the m×n solar cells in the m solar cell strings are tested for poor solder joints. After obtaining the location information of all poor solder joints 6 in the m×n solar cells, each poor solder joint 6 on all solar cells in each solar cell string is repaired, so that all poor solder joints 6 on the m×n solar cells that make up the photovoltaic module are repaired.

[0047] Once the cold solder joint detection module detects the position information of all cold solder joints 6 on n battery cells in the battery string or the position information of all cold solder joints 6 on m×n battery cells, it transmits the position information of each cold solder joint 6 to the control system (not shown in the figure). The power module 4 and the laser processing module 5 then operate according to the instructions issued by the control system.

[0048] In this embodiment, before laminating and laying the m battery strings, all the faulty solder joints 6 on the m battery strings are repaired.

[0049] During repair, a reverse voltage is applied near the malfunctioning solder joint 6, causing the malfunctioning solder joint 6 to be subjected to a reverse voltage, and the malfunctioning solder joint 6 is then laser-scanned, thereby repairing the malfunctioning solder joint 6.

[0050] Specifically, the power module 4 includes a power supply unit and a probe unit. The power supply unit is electrically connected to the probe unit. When a reverse voltage is applied to the dummy solder joint 6, the probe array 41 of the probe unit presses onto the solder strip on the battery cell near the dummy solder joint 6.

[0051] When the probe array 41 of the probe unit presses onto the solder strip on the battery cell near the dummy solder joint 6, and the power supply unit is activated to supply power to the probe unit, the entire battery cell can be subjected to a reverse voltage, thereby applying a reverse voltage to the dummy solder joint 6 on the battery cell pressed by the probe array 41, and the dummy solder joint 6 is laser-scanned by the laser processing module 5, so that the dummy solder joint 6 is repaired while the reverse voltage is applied and the laser scanning is performed.

[0052] The specific structures of the power supply module 4 and the laser processing module 5 are existing technologies and will not be described in detail in this application. It is understood that, in order to apply a reverse voltage to the battery cell, in addition to the probe unit and the power supply unit, other structures are included, such as a conductive plate. The conductive plate is electrically connected to the power supply unit, and the back of the battery cell is in contact with the conductive plate. When a reverse voltage is applied to the battery cell, the power supply unit activates to supply power to the probe unit and the conductive plate, forming an electrical circuit, thereby applying a reverse voltage to the battery cell.

[0053] Furthermore, the vertical distance between the position of the probe array 41 pressing on the battery cell and the faulty solder joint 6 to be repaired is less than or equal to 30cm.

[0054] In this embodiment, the vertical distance refers to the distance between the dummy solder point 6 and the position where the probe array 41 presses onto the battery cell in a direction perpendicular to the length direction of the probe array 41.

[0055] When the probe array 41 presses against the solar cell and applies a reverse voltage to the entire solar cell, the area farther away from the probe array 41 is more strongly affected by the voltage drop. In this embodiment, setting the vertical distance between the position of the probe array 41 pressing against the solar cell and the solder joint 6 to be repaired to less than or equal to 30cm can reduce the impact of the voltage drop on the solder joint 6, allowing the solder joint 6 to be effectively repaired. Furthermore, during the repair process, the solder joint 6 is not blocked by the probe array 41, allowing the laser to directly irradiate the solder joint 6.

[0056] To prevent the battery cells from being damaged when a reverse voltage is applied, in this embodiment, the reverse voltage applied to each poor solder joint 6 does not exceed 30V, preferably not more than 20V.

[0057] In addition, in order to repair the poor solder joint 6, when performing laser scanning on the poor solder joint 6 in this embodiment, the laser power applied to the poor solder joint 6 is between 1 and 1000W, and the preferred laser power is between 15 and 300W.

[0058] Understandably, before the m cell strings are laminated, all the faulty solder joints 6 in the m cell strings need to be detected and repaired in order to improve the overall contact performance of the final photovoltaic module.

[0059] When repairing the cold solder joint 6, after the probe array 41 is pressed on the solder strip on the battery cell and the laser of the laser processing module 5 is located above the battery cell, the power supply unit and the laser processing module 5 can be started simultaneously to apply a reverse voltage to the cold solder joint 6 while performing laser scanning; alternatively, the power supply unit can be started first, followed by the laser processing module 5, to apply a reverse voltage to the cold solder joint 6 first, and then perform laser scanning on the cold solder joint 6 with the applied reverse voltage; or the laser processing module 5 can be started first, followed by the power supply unit, to perform laser scanning on the cold solder joint 6 first, and then apply a reverse voltage to the laser-scanned cold solder joint 6.

[0060] This embodiment does not impose specific restrictions on the order in which the power supply unit and the laser processing module 5 are started, as long as there is a time period during which a reverse voltage is applied and a laser scan is performed when the poor solder joint 6 is repaired.

[0061] In addition, in this embodiment, the order of applying reverse voltage to the dummy solder joint 6 and performing laser scanning can be controlled by first activating the power supply unit to power on the probe unit and then controlling the order of pressing down the probe array 41 and starting the laser processing module 5.

[0062] Figure 1 This is a schematic diagram showing the distribution of the 6 faulty solder joints on the individual cells of the battery string. It is understandable that... Figure 1This is just a schematic diagram to illustrate the distribution of the faulty solder joints 6 on the battery string. The distribution of faulty solder joints 6 on the battery string is irregular. Some battery cells may have faulty solder joints 6, some battery cells may not have faulty solder joints 6, and some battery cells may have multiple faulty solder joints 6.

[0063] This embodiment can repair the faulty solder joint 6 on one battery cell before repairing the faulty solder joint 6 on other battery cells in the battery string. In this case, only one power module 4 is needed, and the laser processing module 5 only needs to include one laser. Alternatively, faulty solder joint 6 on two or more battery cells in the battery string can be repaired simultaneously. For example, when repairing faulty solder joint 6 on two battery cells in the battery string at the same time, two power modules 4 are set up, and the laser processing module 5 includes two lasers. While one power module 4 and laser repair one faulty solder joint 6 on one battery cell, the other power module 4 and laser repair one faulty solder joint 6 on another battery cell.

[0064] When there is only one faulty solder joint 6 on a battery cell, it is only necessary to apply a reverse voltage to the battery cell near the faulty solder joint 6 (the vertical distance between the position of the probe array 41 pressing on the battery cell and the faulty solder joint 6 is less than or equal to 30cm) through the power module 4, and then use the laser processing module 5 to perform laser scanning on it, so that the faulty solder joint 6 can be repaired.

[0065] When a solar cell has two or more faulty solder joints 6, when a reverse voltage is applied near one of the faulty solder joints 6, the faulty solder joints 6 whose vertical distance from the location where the reverse voltage is applied is less than or equal to 30 cm are repaired simultaneously. For the faulty solder joints 6 on the solar cell whose vertical distance from the location where the first reverse voltage is applied is greater than 30 cm, a reverse voltage is applied again at a location whose vertical distance from the faulty solder joint 6 is less than or equal to 30 cm and laser scanning is used to repair them, until all the faulty solder joints 6 on the solar cell are repaired.

[0066] Specifically, this will be illustrated using the example of two faulty solder joints (6) on a single solar cell. (Reference) Figure 2 If the two faulty solder joints 6 are very close together, and the vertical distance between the position of the probe array 41 pressing on the battery cell and the two faulty solder joints 6 is less than or equal to 30cm, the two faulty solder joints 6 on the battery cell can be repaired simultaneously at the same time; (Reference) Figure 3If the two faulty solder joints 6 are far apart, and when the probe array 41 is pressed near one of the faulty solder joints 6 (vertical distance less than or equal to 30cm), the vertical distance between it and the other faulty solder joint 6 is greater than 30cm, then the two faulty solder joints 6 need to be repaired separately. That is, after the probe array 41 is pressed near one of the faulty solder joints 6 to apply a reverse voltage to the cell and performs a laser scan to complete the repair of the faulty solder joint 6, the probe array 41 is then pressed near the other faulty solder joint 6 to apply a reverse voltage to it and perform a laser scan to repair it.

[0067] In another embodiment, when a single cell has two or more faulty solder joints 6, a reverse voltage is applied to the cell once or multiple times and a laser scan is performed to repair all the faulty solder joints 6 on the single cell.

[0068] In this embodiment, there is no specific limitation on the vertical distance between the position of the probe array 41 pressed on the battery cell and the vacant solder joint 6 to be repaired. During the process of applying a reverse voltage to the solder strip on the battery cell and scanning it with a laser while the probe array 41 is pressed on the battery cell, all the vacant solder joints 6 on the battery cell can be repaired, or some of the vacant solder joints 6 in the battery cell can be repaired. At this time, the probe array 41 is pressed on the solder strip on the battery cell again to apply a reverse voltage to the battery cell (preferably, the position is not the same as the position where the reverse voltage was applied for the first time) and scanned with a laser so that the remaining vacant solder joints 6 in the battery cell are repaired. That is, by applying a reverse voltage to a single battery cell and scanning it with a laser once or multiple times, all the vacant solder joints 6 on the battery cell can be repaired.

[0069] All poor solder joints on the photovoltaic module are repaired during laser scanning while a reverse voltage is applied, thus repairing the contact loss caused by welding, effectively reducing the power loss of the final photovoltaic module, and making the actual module power close to the theoretical value.

[0070] Once the solder joint detection module detects all the solder joints 6 on n cells in a battery string, or after detecting all the solder joints 6 on m×n cells that have formed a conductive connection structure, it uploads the position information of each solder joint 6 to the control system. The laser of the laser processing module 5 then moves to above the solder joint 6 to be repaired based on the position information received from the control system. Alternatively, the laser can remain stationary while the battery string is moved to move the solder joint 6 to below the laser. Then, the probe array 41 presses down onto the solder strip within 30cm (inclusive) of the vertical distance from the solder joint 6 according to the location information of the solder joint 6 to be repaired. Then, the power supply unit energizes the probe array 41 to apply a reverse voltage to the battery cell with the solder joint 6, so that all solder joints 6 within 30cm (inclusive) of the vertical distance from the pressing position of the probe array 41 are repaired. Then, other solder joints 6 in the battery string are repaired in the same way until all solder joints 6 in the battery string are repaired.

[0071] Alternatively, the location information of each faulty solder joint 6 can be uploaded to the control system. After the faulty solder joint 6 to be repaired is located below the laser, the probe array 41 is pressed onto the area outside the faulty solder joint 6 on the cell to be repaired to apply reverse voltage and perform laser scanning. By applying reverse voltage and performing laser scanning on the cell once or multiple times, all the faulty solder joints 6 on the cell can be repaired.

[0072] The repair results for a cell are shown in Table 1, after all the faulty solder joints on a cell in a battery string are repaired during the time period when a reverse voltage is applied and a laser scan is performed.

[0073] Table 1 Comparison of performance parameters of the battery cells after repair, before stringing, and after stringing.

[0074] Comment Isc / A Uoc / V FF / % Eta / % Rs / mΩ Rsh / Ω IRev2 / A Pmpp / W T / ℃ Before string welding 6.905 0.7250 81.65 24.72 0.0032 2118 0.0120 4.085 19.4 After stringing 6.908 0.7253 81.10 24.55 0.0042 3222 0.0156 4.059 19.8 After laser repair 6.907 0.7247 81.60 24.70 0.0031 1942 0.0169 4.098 20.5

[0075] Electrical performance tests were performed on the same solar cell before stringing, after stringing, and after laser repair, and the performance parameters are shown in Table 1. Specifically, the electrical performance tests before stringing were performed by pressing the probe array onto the grid lines, while the electrical performance tests after stringing and laser repair were performed by pressing the probe array onto the solder strip.

[0076] As shown in Table 1, the difference in FF, Eta, and Pmpp of the solar cells after laser repair is small compared with those before stringing, and there is a significant improvement compared with those after stringing.

[0077] The repair results are shown in Table 2 after all the faulty solder joints on the m×n cells of the photovoltaic module were repaired during the time period when a reverse voltage was applied and laser scanning was performed.

[0078] Table 2 compares the performance parameters of the photovoltaic module after all solder joints were repaired with those after the module's performance degraded.

[0079] Comment Pmpp / W Vmpp / V Impp / A Uoc / V Isc / A After attenuation 16.15 1.22 13.16 1.44 13.83 After repair 16.24 1.24 13.19 1.45 13.83

[0080] As shown in Table 2, the method described in this embodiment can effectively repair contact losses caused during the welding process and reduce the power loss of the components.

[0081] refer to Figure 2-4 In the production process of photovoltaic modules, n solar cells are welded together in series at welding device 1. After the m×n solar cells are arranged into a conductive connection structure according to the module layout requirements, they are conveyed to laminating device 2 via conveyor module 3 (e.g., belt) to obtain the photovoltaic module. The cold solder joint detection module, power supply module 4, and laser processing module 5 of this application can be set at any of the welding device 1, conveyor module 3, and laminating device 2 according to actual needs. For example, the cold solder joint detection module can be set at welding device 1, and after welding, the cold solder joints 6 on each solar cell in the string are detected. The power supply module 4 and laser processing module 5 can be set at any of the welding device 1, conveyor module 3, and laminating device 2. In this application, the power supply module 4 and the laser processing module 5 are located in the same device. The cold solder joint detection module can be located in the same device as the power supply module 4 and the laser processing module 5, or it can be located in the process before the power supply module 4 and the laser processing module 5. As long as the cold solder joint detection module can detect all the cold solder joints 6 on the battery string or all the cold solder joints 6 on m×n battery cells before the power supply module 4 and the laser processing module 5 start to repair the cold solder joints 6, it is sufficient.

[0082] It is understandable that when the power module 4 and the laser processing module 5 are located at the welding device 1, they should not affect the welding process of each battery cell by the welding device 1. Similarly, when the power module 4 and the laser processing module 5 are located at the laminating device 2, they should not affect the laminating process of the laminating device 2. In this case, after all the false solder joints 6 on the m battery strings are repaired at the laminating device 2, the lamination is carried out at the laminating device 2, and then the lamination is carried out again through the laminating device 2.

[0083] The various embodiments in this specification are described in a progressive, parallel, or combined manner. Each embodiment focuses on its differences from other embodiments, and similar or identical parts between embodiments can be referred to interchangeably. For the apparatuses disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant parts can be referred to the method section.

[0084] It should be noted that, in the description of this application, the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component centrally located at the same time.

[0085] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0086] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for repairing poor solder joints in a photovoltaic module, wherein the photovoltaic module comprises m cell strings, each cell string comprising n cells connected in series, characterized in that, Includes the following steps: S1: After connecting n solar cells together to form a solar cell string, and before laminating the m solar cell strings, perform a cold solder joint detection on the solar cell strings to obtain the location information of all cold solder joints on the n solar cells in the solar cell string; or after forming a conductive connection structure of m×n solar cells according to the module layout requirements, and before laminating the m solar cell strings, perform a cold solder joint detection on the m×n solar cells in the m solar cell strings to obtain the location information of all cold solder joints on the m×n solar cells; S2: Before laminating m battery strings, all the faulty solder joints in the battery strings are repaired. The repair of all faulty solder joints in m×n battery cells includes repairing each faulty solder joint when laser scanning is performed while applying reverse voltage.

2. The method for repairing poor solder joints in photovoltaic modules according to claim 1, characterized in that, During repair, a reverse voltage is applied near the solder joint to cause the solder joint to be subjected to a reverse voltage, and the solder joint is then laser-scanned to repair the solder joint.

3. The method for repairing poor solder joints in photovoltaic modules according to claim 2, characterized in that, The vertical distance between the malfunctioning solder joint and the location where reverse voltage is applied is less than or equal to 30 cm.

4. The method for repairing poor solder joints in photovoltaic modules according to claim 3, characterized in that, When a solar cell has two or more faulty solder joints, when a reverse voltage is applied near one of the faulty solder joints, the faulty solder joints that are 30 cm or less in vertical distance from the location where the reverse voltage is applied are repaired simultaneously. For the faulty solder joints on the solar cell that are more than 30 cm in vertical distance from the location where the reverse voltage was first applied, a reverse voltage is applied again at a location that is 30 cm or less in vertical distance from the faulty solder joint and laser scanning is used to repair them, until all the faulty solder joints on the solar cell are repaired.

5. The method for repairing poor solder joints in photovoltaic modules according to claim 1, characterized in that, When a single solar cell has two or more faulty solder joints, a reverse voltage is applied to the solar cell once or multiple times and a laser scan is performed to repair all the faulty solder joints on the single solar cell.

6. A method for repairing poor solder joints in photovoltaic modules according to any one of claims 1-5, characterized in that, The method for detecting cold solder joints is one or more of EL detection, PL detection, or infrared thermal imaging detection.

7. A method for repairing poor solder joints in photovoltaic modules according to any one of claims 1-5, characterized in that, The reverse voltage applied to each of the aforementioned dummy solder joints shall not exceed 30V.

8. A method for repairing poor solder joints in photovoltaic modules according to claim 7, characterized in that, The reverse voltage applied to each of the aforementioned dummy solder joints shall not exceed 20V.

9. A method for repairing poor solder joints in photovoltaic modules according to any one of claims 1-5, characterized in that, When performing laser scanning on the malfunctioning solder joint, the laser power applied to the malfunctioning solder joint is 1 to 1000 W.

10. A method for repairing poor solder joints in photovoltaic modules according to claim 9, characterized in that, When performing laser scanning on the malfunctioning solder joints, the laser power applied to the malfunctioning solder joints is 15 to 300 W.

11. A system for repairing poor solder joints in photovoltaic modules, characterized in that, It includes a cold solder joint detection module, a power supply module, and a laser processing module. The cold solder joint detection module performs cold solder joint detection on all battery strings obtained by string welding or whole-plate welding, and obtains the position information of all cold solder joints on n battery cells in the battery string or the position information of all cold solder joints on m×n battery cells. The power supply module is used to apply reverse voltage to the cold solder joints, and the laser processing module is used to perform laser scanning on the cold solder joints. Each faulty solder joint was repaired during the time period when the power supply module applied a reverse voltage to it and the laser processing module performed a laser scan on it.

12. The system for repairing poor solder joints in photovoltaic modules according to claim 11, characterized in that, The power module includes a power supply unit and a probe unit. The power supply unit is electrically connected to the probe unit. When a reverse voltage is applied to the dummy solder joint, the probe array of the probe unit presses onto the solder strip on the battery cell near the dummy solder joint.

13. A system for repairing poor solder joints in photovoltaic modules according to claim 12, characterized in that, When a reverse voltage is applied to a dummy solder joint, the vertical distance between the position of the probe array of the probe unit pressed on the solder strip on the battery cell and the dummy solder joint is less than or equal to 30 cm.

14. The system for repairing poor solder joints in photovoltaic modules according to claim 11, characterized in that, When a single cell has two or more faulty solder joints, the probe array of the probe unit is pressed onto the solder strip on the cell one or more times to apply reverse voltage to the cell one or more times, and the cell is then laser-scanned by a laser processing module to repair all the faulty solder joints on the single cell.

15. A system for repairing poor solder joints in photovoltaic modules according to any one of claims 11-14, characterized in that, The cold solder joint detection module is one or more of an EL detector, a PL detector, or an infrared thermal imaging detector.

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