Photovoltaic module manufacturing process

Abstract

This application relates to the technical field of solar cells and discloses a manufacturing process for photovoltaic modules. The solar cell of the photovoltaic module includes a high-temperature region and a low-temperature region. Among them, the high-temperature region is the region where the grid lines and solder tapes of the solar cell are welded; the low-temperature region is the edge region of the solar cell; the heating temperature value of the high-temperature region is greater than the heating temperature value of the low-temperature region. This solves the problem that it is difficult for traditional overall heating to take into account the differences in heat requirements of different parts of the cell during welding. In this application, the zone heating can set different temperatures according to the characteristics of each region, avoiding different shrinkage degrees caused by different expansion coefficients of different materials under high-temperature heating conditions, thereby reducing uneven thermal stress, reducing the risk of cell warping, ensuring the welding quality, maintaining the structural stability of the cell, and being beneficial to improving the yield of the photovoltaic module formed after lamination.

Description

Technical Field

[0001] This application relates to the technical field of solar cells, and particularly to a manufacturing process for photovoltaic modules. Background Art

[0002] In the current booming environment of the solar energy industry, as a core component, the production and manufacturing process of solar cells has attracted much attention. Among them, the technical maturity of solar cells in the welding stage has a crucial impact on the performance and yield of the cells. At present, in the welding process of solar cells, the problem of welding warping is relatively prominent.

[0003] From a microscopic perspective, due to the difference in thermal expansion coefficients between silicon and the solder tape, the expansion coefficient of the solder tape is greater than that of silicon. During the shrinkage process after welding, the shrinkage degree of the solder tape is greater than that of silicon, and this difference in shrinkage degree will cause the cell to warp. At the same time, during actual welding operations, because the welding temperature is relatively high, taking the common light box heating welding as an example, the temperature of the light box can reach 300°C. Such a high temperature will cause the peripheral edge area of the photovoltaic cell to warp due to uneven heating. The negative impacts brought about by this warping cannot be underestimated. It will not only cause poor connection between the solder tape and the wire, affecting the electrical conductivity of the cell, thereby reducing the power generation efficiency of the solar cell; in severe cases, it will also cause the cell to break, directly resulting in product scrapping, greatly increasing the production cost and reducing the production efficiency. This series of problems urgently need to be solved through innovative welding technologies or process improvements. Summary of the Invention

[0004] The purpose of the embodiments of this application is to provide a manufacturing process for photovoltaic modules, so as to reduce the warping problem caused by uneven heating due to the difference in expansion coefficients during the welding of photovoltaic modules.

[0005] To solve the above technical problems, the embodiments of this application provide a manufacturing process for photovoltaic modules. The photovoltaic module includes a solar cell and a solder tape; the solar cell is printed with grid lines for welding with the solder tape; the solar cell includes a high-temperature area and a low-temperature area; wherein, the high-temperature area is the area where the grid lines of the solar cell are welded with the solder tape; the low-temperature area is the edge area of the solar cell; the heating temperature value of the high-temperature area is greater than that of the low-temperature area.

[0006] In the embodiments of the present application, by heating the solar cell in zones, and taking the areas where the grid lines and the solder tapes need to be welded as the high-temperature zones, and taking the edge areas of the cell as the low-temperature zones, different temperatures are used for heating in different zones, so that during the welding process, the temperatures of different areas of the solar cell can be accurately regulated; this solves the problem that it is difficult to take into account the different thermal requirements of different parts of the cell during welding in traditional overall heating. In the present application, different temperatures can be set for the zonal heating according to the characteristics of each zone, avoiding different shrinkage degrees caused by different expansion coefficients of different materials under high-temperature heating conditions, thereby reducing uneven thermal stress, reducing the risk of cell warping, ensuring the welding quality, maintaining the structural stability of the cell, and being beneficial to improving the yield of the photovoltaic module formed after lamination.

[0007] In addition, the temperature value of the target point changes linearly with the distance between the target point and the high-temperature zone, and the range of the temperature value change rate is -10 °C / mm to -5 °C / mm; wherein, the position of the target point is any point outside the high-temperature zone of the solar cell.

[0008] In addition, between the high-temperature zone and the low-temperature zone, there are also a plurality of temperature transition zones, and the temperature transition zones are used to transition the temperature between the high-temperature zone and the low-temperature zone; the temperature values of each temperature transition zone decrease sequentially in the direction from the high-temperature zone to the low-temperature zone.

[0009] In addition, the temperature transition zone is provided with a heat dissipation material, and the temperature values in the direction from the high-temperature zone to the low-temperature zone change in a stepped linear manner; wherein, the temperature value change rate k1 of the temperature value transition zone < the temperature value change rate k2 of the low-temperature zone.

[0010] In addition, the temperature transition zone includes a first temperature transition zone and a second temperature transition zone; the heat dissipation materials of the first temperature transition zone and the second temperature transition zone are different; the value range of the temperature value change rate k2 of the low-temperature zone is -3 °C / mm to -2 °C / mm; the value range of the temperature value change rate k3 of the first temperature transition zone is -10 °C / mm to -8 °C / mm; the value range of the temperature value change rate k4 of the second temperature transition zone is -5 °C / mm to -3 °C / mm.

[0011] In addition, the temperature difference range between the high-temperature zone and the low-temperature zone is 250 °C to 10 °C.

[0012] In addition, the value range of the width value d of the high-temperature zone is 150 mm to 185 mm.

[0013] In addition, the width value D of the low-temperature zone is equal to the width value of the solar cell; and the ratio of the width value d of the high-temperature zone to the width value D of the low-temperature zone is 85% to 95%.

[0014] In addition, the width range of each of the temperature transition zones is 2 mm to 6 mm; the temperature difference between adjacent temperature transition zones is 15°C to 30°C.

[0015] In addition, the high-temperature zone includes a plurality of sub-high-temperature zones; each sub-high-temperature zone includes an area where a row of grid lines is welded to the solder strip; or each sub-high-temperature zone includes an area where a column of grid lines is welded to the solder strip. Description of the Drawings

[0016] One or more embodiments are illustrated by way of example in the accompanying drawings, and these exemplary illustrations do not limit the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the drawings in the figures do not constitute a scale limitation.

[0017] Figure 1 is a schematic structural diagram of a photovoltaic module in a photovoltaic module production process provided by an embodiment of the present application;

[0018] Figure 2 is a schematic structural diagram of a photovoltaic module in a photovoltaic module production process provided by another embodiment of the present application;

[0019] Figure 3 is a schematic partial structural diagram of a photovoltaic module in a photovoltaic module production process provided by an embodiment of the present application;

[0020] Figure 4 is a relationship curve diagram of the temperature value of a target point and the distance between the target point and the high-temperature zone in a photovoltaic module production process provided by an embodiment of the present application;

[0021] Figure 5 is a schematic partial structural diagram of a photovoltaic module in a photovoltaic module production process provided by another embodiment of the present application;

[0022] Figure 6 is a relationship curve diagram of the temperature value of a target point and the distance between the target point and the high-temperature zone in a photovoltaic module production process provided by another embodiment of the present application;

[0023] Figure 7 is a flowchart of a photovoltaic module welding method provided by an embodiment of the present application. Detailed Description of the Embodiments

[0024] Due to the difference in the coefficient of thermal expansion between silicon and the solder strip, and the expansion coefficient of the solder strip being greater than that of silicon, during the shrinkage process after welding, the shrinkage degree of the solder strip is greater than that of silicon, and this difference in shrinkage degree will cause the battery chip to warp.

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will elaborate on each embodiment of this application in conjunction with the accompanying drawings. However, those of ordinary skill in the art can understand that in each embodiment of this application, many technical details are provided to help readers better understand this application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in this application can still be implemented. The division of the following embodiments is for convenience of description and should not constitute any limitation to the specific implementation of this application. Under the premise of no contradiction, the various embodiments can be combined and cross-referenced with each other.

[0026] An embodiment of this application relates to a photovoltaic module manufacturing process, which can be applied to the production process of solar cells that require heating and welding, such as monocrystalline silicon solar cells, polycrystalline silicon solar cells, thin-film solar cells, perovskite solar cells, back-contact (BC) cells, tunnel oxide passivated contact (TOPCON) cells, and passivated emitter and rear cell (PERC) cells. The photovoltaic module includes a solar cell and a solder ribbon; the solar cell is printed with grid lines for welding with the solder ribbon; the solar cell includes a high-temperature area and a low-temperature area; among them, the high-temperature area is the area where the grid lines of the solar cell are welded to the solder ribbon; the low-temperature area is the edge area of the solar cell; the heating temperature value of the high-temperature area is greater than that of the low-temperature area. By heating the solar cell in zones and using different temperatures for heating in zones, with the area where the grid lines and the solder ribbon need to be welded as the high-temperature area and the edge area of the cell as the low-temperature area, precise temperature control can be achieved for different areas of the solar cell during the welding process; this solves the problem that it is difficult to balance the different thermal requirements of different parts of the cell during welding in traditional overall heating. In this application, the zone heating can set different temperatures according to the characteristics of each zone, avoiding different shrinkage degrees caused by different expansion coefficients of different materials under high-temperature heating, thereby reducing uneven thermal stress and the risk of cell warping, ensuring the welding quality while maintaining the structural stability of the cell. The following specifically describes the implementation details of the photovoltaic module manufacturing process of the embodiments of this application. The following content is only provided for convenience of understanding and is not necessary for implementing this solution.

[0027] As Figure 1 shown, the photovoltaic module includes a solar cell 1 and a solder ribbon 2; the solar cell 1 is printed with grid lines for welding with the solder ribbon; as Figure 2As shown, the solar cell 1 includes a high-temperature region 101 and a low-temperature region 102; wherein, the high-temperature region is the region where the grid lines and solder tapes of the solar cell are welded; the low-temperature region 102 is the edge region of the solar cell 1; the heating temperature value of the high-temperature region 101 is greater than the heating temperature value of the low-temperature region 102.

[0028] In some embodiments, the value range of the width d of the high-temperature region 101 is 150 mm to 185 mm. Further, in order to avoid warping of the low-temperature region 102 cells and ensure good welding effect between the solder tape 2 and the cells in a larger area, the width d of the high-temperature region 101 is controlled within the range of 160 mm to 170 mm; for example, the value of the width d of the high-temperature region 101 can be 160 mm, 162 mm, 165 mm, 168 mm, 170 mm, etc. It should be noted that those skilled in the art can adjust the specific value or value range of the width d of the high-temperature region 101 according to actual production requirements, and this application does not limit it here.

[0029] In some other embodiments, the width value D of the low-temperature region 102 is equal to the width value of the solar cell 1; and the ratio of the width value d of the high-temperature region 101 to the width value D of the low-temperature region 102 is 85% to 95%. Further, the ratio of the width d of the high-temperature region 101 to the width D of the cell is 87.5% to 93%. For example, when the ratio of the width d of the high-temperature region 101 to the width D of the cell is 93%, if the width of the cell is 172 mm, the width value of the high-temperature region 101 is 160 mm; when the ratio of the width d of the high-temperature region 101 to the width D of the cell is 87.5%, if the width of the cell is 195 mm, the width value of the high-temperature region 101 is 170 mm. It should be noted that those skilled in the art can adjust the specific value or value range of the ratio of the width d of the high-temperature region 101 to the width D of the cell according to actual production requirements, and this application does not limit it here.

[0030] Specifically, the low-temperature region 102 is the edge region of the solar cell 1, and the division of the low-temperature region 102 can be a region that maintains a preset edge distance from the edge of the solar cell 1; in order to ensure that the low-temperature region 102 does not overlap with the high-temperature region 101, the preset edge distance L ≤ (width D of the cell - width d of the high-temperature region) / 2.

[0031] In some embodiments, the temperature difference range between the high-temperature region 101 and the low-temperature region 102 is 250°C to 10°C. Further, the temperature difference range between the high-temperature region 101 and the low-temperature region 102 is 150°C to 50°C. During the welding process, the high-temperature region 101 of the solar cell 1 in the photovoltaic module is heated and welded at a temperature of 200°C to 300°C, and the heating temperatures set for other regions are lower than the temperature of the high-temperature region 101. In some specific embodiments, the lowest welding temperature designed for the outermost edge of the low-temperature region 102 is 150°C, and the welding temperature of the high-temperature region 101 is 270°C. It should be noted that those skilled in the art can adjust the specific value or value range of the width value d of the high-temperature region 101 according to actual production requirements, and this application does not limit it here.

[0032] Further, as Figure 3 shown, in some embodiments, between the high-temperature region 101 and the low-temperature region 102, there are also a plurality of temperature transition regions, and the temperature transition regions are used to transition the temperature between the high-temperature region 101 and the low-temperature region 102; the temperature values of each of the temperature transition regions decrease sequentially in the direction from the high-temperature region 101 to the low-temperature region 102. The low-temperature region 102 and the temperature transition regions can be regarded as regions of the battery cell that are prone to warping due to relatively high temperatures during the welding stage except for the regions that need to be welded at high temperatures; among them, the low-temperature region 102 is closer to the edge region of the solar cell 1; and the temperature transition regions are the regions located between the high-temperature region 101 and the low-temperature region 102.

[0033] In some embodiments, the width range of each of the temperature transition regions is 2 mm to 6 mm; the temperature difference between adjacent temperature transition regions is 15°C to 30°C. Specifically, when the same heat dissipation material is used between adjacent temperature transition regions, the temperature difference between the temperature transition regions is 15°C to 30°C. In some specific embodiments, the width of each temperature transition region is 3 mm, and the average temperature of each temperature transition region is regarded as the temperature of this temperature transition region.

[0034] As Figure 4 shown, Figure 4 the abscissa is the distance x between the target point and the high-temperature region 101, Figure 4 the ordinate is the temperature y of the target point, and the position of the target point is any point outside the high-temperature region 101 of the solar cell 1. The temperature value of the target point changes linearly with the distance between the target point and the high-temperature region 101, and the range of the temperature change rate is -10°C / mm to -5°C / mm. The temperature change rate, that is, the ratio of the temperature value of the target point to the distance between the target point and the high-temperature region 101, that is Figure 4The slope k of the temperature change curve of the target point. Since the temperature gradually decreases in the direction away from the high-temperature area, the value of k is less than 0. When the target point moves away from the high-temperature area 101 along a straight line from the edge of the high-temperature area 101 to the edge of the battery cell, for every preset distance away from the high-temperature area 101, the temperature drops by a preset amplitude. Specifically, the variation law of the temperature y of the target point with the distance x of the target point from the high-temperature area 101 satisfies the following equation:

[0035]

[0036] where k is the temperature change rate, -10°C / mm ≤ k ≤ -5°C / mm, and T is the welding temperature of the high-temperature area 101. For example, in one embodiment, the value of k is -7.5°C / mm and the welding temperature of the high-temperature area 101 is 270°C, then the variation law of the temperature y of the target point with the distance x of the target point from the high-temperature area 101 is y = -7.5x + 270. Under this heating condition, for every 3 mm the target point moves away from the high-temperature area, the temperature of the target point drops by 22.5°C. In another embodiment, the value of k is -5°C / mm and the welding temperature of the high-temperature area 101 is 300°C, then the variation law of the temperature y of the target point with the distance x of the target point from the high-temperature area 101 is y = -5x + 300. Under this heating condition, for every 5 mm the target point moves away from the high-temperature area, the temperature of the target point drops by 15°C. It should be noted that T is the welding temperature of the high-temperature area 101. During the welding process, the welding temperature of the high-temperature area 101 remains constant. Those skilled in the art can adjust the specific values or value ranges of the welding temperature of the high-temperature area 101 and the temperature change rate according to actual production requirements, and this application does not limit them here.

[0037] Specifically, due to the complex heating conditions and heating environment, various effects will be exerted on the actual heating temperature. The temperature value of the target point can be ensured to vary linearly with the distance between the target point and the high-temperature area 101 through further temperature control settings. First, a special design is made for the heating plate: heating wires or heating elements with a higher density are arranged in the middle area, while the distribution density of heating wires or elements is reduced in the surrounding area; a heating plate material with non-uniform heat conduction performance is adopted, with a material with good heat conduction performance, such as a high-purity metal heat conduction material, used in the middle part, and a material with relatively poor heat conduction performance, such as ceramics or an alloy with a low heat conduction coefficient, used in the surrounding part. Alternatively, a heating system with independent temperature control for multiple regions is adopted: independent temperature sensors and heating controllers are equipped for different heating regions; multiple heating lamps or heating modules are used in the heating device and are distributed above the battery cell at different angles and positions. Second, the heating process is adjusted: different control adjustments are made to the heating time and heating speed of different regions; or the heating environment air pressure of different regions is changed during the heating process. Third, auxiliary tools or materials are set for heat conduction, and heat conduction blocks with special shapes, such as wedge-shaped heat conduction blocks, are placed. It should be noted that those skilled in the art can adjust the specific manner of temperature control according to actual production requirements to maintain the linear change of the temperature value, and the present application does not limit this here.

[0038] In some other embodiments, a heat dissipation material is provided in the temperature transition area, and the temperature value in the direction from the high-temperature area 101 to the low-temperature area 102 changes in a stepped linear manner. Among them, the temperature value change rate k1 of the temperature transition area < the temperature value change rate k2 of the low-temperature area 102. The temperature value change rate k1 of the temperature transition area, that is, the ratio of the temperature value of the target point in the temperature transition area to the distance between the target point and the high-temperature area 101, that is, the slope k1 of the temperature change curve of the target point; the temperature value change rate k2 of the low-temperature area 102, that is, the ratio of the temperature value of the target point in the low-temperature area 102 to the distance between the target point and the high-temperature area 101, that is, the slope k2 of the temperature change curve of the target point; due to the addition of a heat dissipation material in the temperature transition area, the temperature change range in the temperature transition area is larger, so k1 < k2.

[0039] Specifically, during the welding heating process, a heat-conducting material capable of absorbing heat is arranged near the temperature transition area, so that the temperature transition area can dissipate more heat and quickly reduce the temperature. In some embodiments, such as Figure 5As shown, the temperature transition zone includes a first temperature transition zone and a second temperature transition zone; the heat dissipation materials of the first temperature transition zone and the second temperature transition zone are different. Among them, the first temperature transition zone is close to the high-temperature zone 101, and the second temperature transition zone is close to the low-temperature zone 102. In the direction from the high-temperature zone 101 to the low-temperature zone 102, they are, in sequence, the high-temperature zone 101, the first temperature transition zone, the second temperature transition zone, and the low-temperature zone 102. It should be noted that those skilled in the art can set multiple first temperature transition zones and second temperature transition zones according to actual production requirements, or set a third temperature transition zone, etc., and this application does not limit this here.

[0040] It should be noted that in some embodiments, due to the different heat dissipation materials selected for the first temperature transition zone and the second temperature transition zone, the temperature value change rate k3 of the first temperature transition zone < the temperature value change rate k4 of the second temperature transition zone < 0; it can also be 0 > the temperature value change rate k3 of the first temperature transition zone > the temperature value change rate k4 of the second temperature transition zone, such as Figure 6 As shown, the change range of the temperature value change rate of the first temperature transition zone (i.e., the line segment where the temperature y of the target point drops from T to y1') is smaller than the change range of the temperature value change rate of the second temperature transition zone (i.e., the line segment where the temperature y of the target point drops from y1' to y2'). Those skilled in the art can adjust the specific ways of making the specific heat dissipation materials used in the first temperature transition zone and the second temperature transition zone according to actual production or heat dissipation requirements, and this application does not limit this here.

[0041] In the case where the temperature value change rate k3 of the first temperature transition zone < the temperature value change rate k4 of the second temperature transition zone, further, in some embodiments, the temperature value change rate k3 of the first temperature transition zone < the temperature value change rate k4 of the second temperature transition zone < the temperature value change rate k2 of the low-temperature zone. The value range of the temperature value change rate k2 of the low-temperature zone is -3°C / mm to -2°C / mm; the value range of the temperature value change rate k3 of the first temperature transition zone is -10°C / mm to -8°C / mm; the value range of the temperature value change rate k4 of the second temperature transition zone is -5°C / mm to -3°C / mm.

[0042] The variation law of the temperature y1 of the first target point in the first temperature transition zone with the distance x1 from the target point to the high-temperature zone 101 satisfies the following equation:

[0043]

[0044] Among them, k3 is the temperature value change rate of the first temperature transition zone, -10°C / mm ≤ k3 ≤ -8°C / mm, and T is the welding temperature of the high-temperature zone 101.

[0045] The variation law of the temperature y2 at the second target point in the second temperature transition region with respect to the distance x2 between the target point and the high-temperature region 101 satisfies the following equation:

[0046]

[0047] where x2 ≥ x1, k4 is the temperature value change rate in the second temperature transition region, -5°C / mm ≤ k4 ≤ -3°C / mm, and y1’ is the temperature at the junction of the first temperature transition region and the second temperature transition region. That is, the position corresponding to the temperature value y1’ is the position in the first temperature transition region that is farthest from the high-temperature region 101, and it is also the position in the second temperature transition region that is closest to the high-temperature region 101.

[0048] The variation law of the temperature y3 at the third target point in the low-temperature region 102 with respect to the distance x3 between the target point and the high-temperature region 101 satisfies the following equation:

[0049]

[0050] where x3 ≥ x2, k2 is the temperature value change rate in the first temperature transition region, -3°C / mm ≤ k2 ≤ -2°C / mm, and y2’ is the temperature at the junction of the second temperature transition region and the low-temperature region 102. That is, the position corresponding to the temperature value y2’ is the position in the second temperature transition region that is farthest from the high-temperature region 101, and it is also the position in the low-temperature region 102 that is closest to the high-temperature region 101.

[0051] Specifically, in one embodiment, the value of the temperature value change rate k2 in the low-temperature region is -9°C / mm; the value of the temperature value change rate k3 in the first temperature transition region is -9°C / mm; the value of the temperature value change rate k4 in the second temperature transition region is -4°C / mm. Since the temperature value change rate k3 in the first temperature transition region and the temperature value change rate k4 in the second temperature transition region are different, so in Figure 6 the temperature changes in a stepped linear manner.

[0052] In some embodiments, the high-temperature region 101 includes a plurality of sub-high-temperature regions; the sub-high-temperature region includes a region where a row of grid lines is welded to the solder strip; or the sub-high-temperature region includes a region where a column of grid lines is welded to the solder strip. Further, the sub-high-temperature region can also be a single welding point region. It should be noted that those skilled in the art can flexibly adjust the range of the sub-high-temperature region according to actual application requirements, and this application does not limit it here. Further, the range of the high-temperature region can be determined according to the outermost plurality of sub-high-temperature regions in the sub-high-temperature region.

[0053] In the embodiments of the present application, by heating the solar cell in zones, and taking the areas where the grid lines and solder tapes need to be welded as high-temperature zones, and taking the edge areas of the cell as low-temperature zones to heat with different temperatures in zones, during the welding process, the temperatures of different areas of the solar cell can be accurately regulated; this solves the problem that it is difficult for traditional overall heating to take into account the differences in heat requirements of different parts of the cell during welding. In the present application, the zone heating can set different temperatures according to the characteristics of each zone, avoiding different shrinkage degrees caused by different expansion coefficients of different materials under high-temperature heating conditions, thereby reducing uneven thermal stress, reducing the risk of cell warping, ensuring the welding quality, maintaining the structural stability of the cell, and being beneficial to improving the yield of the photovoltaic module formed after lamination.

[0054] The content division of the above method is only for clear description. When implemented, it can be combined into one step or some steps can be split into multiple steps. As long as the same logical relationship is included, it is within the protection scope of the present application; adding insignificant modifications to the algorithm or process or introducing insignificant designs, but not changing the core design of its algorithm and process are within the protection scope of the present application.

[0055] In addition, the examples mentioned in the above embodiments can be freely combined, and any combination method can be understood as an embodiment. The "embodiments" or "examples" appearing at various positions in the specification do not necessarily refer to the same embodiment, nor are they independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art can understand that the embodiments described herein can be combined with other embodiments.

[0056] In summary, specific embodiments of the present subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the structures recited in the claims can be combined in different ways and still achieve the desired results. Additionally, the structures depicted in the drawings do not necessarily require the specific order or sequential order shown to achieve the desired result.

[0057] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order, or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two), unless otherwise clearly and specifically defined.

[0058] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can mean: there is A, there is both A and B, and there is B, these three situations. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0059] In the description of the embodiments of the present application, technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the embodiments of the present application.

[0060] In the description of the embodiments of the present application, features described as "adjacent" to each other (for example, regions, structures, devices) mean and include features with one or more of the disclosed identifiers that are positioned closest to each other (for example, closest). One or more additional features that do not match the one or more disclosed identifiers of the "adjacent" features (for example, additional regions, additional structures, additional devices) may be disposed between the "adjacent" features. In other words, "adjacent" features can be positioned directly adjacent to each other so that no other features intervene between the "adjacent" features; or "adjacent" features can be positioned indirectly adjacent to each other so that at least one feature with an identifier other than the identifier associated with at least one "adjacent" feature is positioned between the "adjacent" features.

[0061] As used herein, "thermal conductive material" means and includes thermal conductive materials such as one or more of the following: Aluminum has good thermal conductivity, is lightweight and low-cost, and can help quickly conduct heat to complete welding; Copper has a high thermal conductivity coefficient, can precisely control heat transfer, and ensure welding quality; Thermal conductive silicone is beneficial to enhancing heat conduction and preventing local overheating during welding from damaging the battery; And like boron nitride ceramics, with its excellent thermal conductivity and insulation properties, can be used as the isolation and thermal conductive material for solar cells during the welding process to ensure the stable progress of the welding work. In addition, "heat dissipation material" means and includes a structure formed of and containing a thermal conductive material.

[0062] Another embodiment of the present application relates to a method for welding a photovoltaic module, as Figure 7 shown, including:

[0063] Step 701: Divide the solar cell into a high-temperature area and a low-temperature area according to the welding area between the solar cell and the solder ribbon. Among them, the high-temperature area is the area where the grid lines of the solar cell are welded to the solder ribbon; the low-temperature area is the edge area of the solar cell; the heating temperature value of the high-temperature area is greater than the heating temperature value of the low-temperature area.

[0064] Step 702: Perform zone welding heating on the high-temperature area according to the preset temperature value corresponding to the high-temperature area; at the same time, perform zone welding heating on the low-temperature area according to the heating temperature value of the low-temperature area.

[0065] In some embodiments, between the high-temperature area and the low-temperature area, there are also multiple temperature transition areas, which are used to transition the temperature between the high-temperature area and the low-temperature area; the temperature values of each temperature transition area decrease in sequence in the direction from the high-temperature area to the low-temperature area; the temperature transition area is provided with a heat dissipation material, and the temperature values in the direction from the high-temperature area to the low-temperature area change in a stepped linear manner. Correspondingly, when multiple temperature transition areas are provided, the method further includes: performing zone welding heating on the high-temperature area according to the preset temperature value corresponding to the temperature transition area.

[0066] In the embodiments of the present application, by performing zone heating on the solar cell, and using the area where the grid lines and the solder ribbon need to be welded as the high-temperature area, and the edge area of the cell as the low-temperature area, different temperatures are used for zone heating, so that during the welding process, the temperature of different areas of the solar cell can be accurately controlled; it solves the problem that it is difficult to take into account the different thermal requirements of different parts of the cell during traditional overall heating. In the present application, the zone heating can set different temperatures according to the characteristics of each area, avoiding different shrinkage degrees caused by different expansion coefficients of different materials under high-temperature heating conditions, thereby reducing uneven thermal stress, reducing the risk of cell warping, ensuring the welding quality, maintaining the structural stability of the cell, and being beneficial to improving the yield of the photovoltaic module formed after lamination.

[0067] It is not difficult to find that this embodiment is a method embodiment corresponding to the above process embodiment, and this embodiment can be implemented in cooperation with the above method embodiment. The relevant technical details mentioned in the above method embodiment are still valid in this embodiment. To avoid repetition, they are not elaborated here. Correspondingly, the relevant technical details mentioned in this embodiment can also be applied to the above method embodiment.

[0068] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present application, and in practical applications, various changes can be made in form and details without departing from the spirit and scope of the present application.

Claims

1. A photovoltaic module manufacturing process, characterized in that: The photovoltaic module comprises a solar cell and a welding strip; the solar cell is printed with a grid line, and the grid line is used for welding with the welding strip; The solar cell comprises a high temperature region and a low temperature region; Wherein, the high temperature area is the area where the grid lines of the solar cell and the welding strips are welded; the low temperature area is the edge area of ​​the solar cell; The heating temperature value of the high temperature zone is greater than the heating temperature value of the low temperature zone; Among them, between the high temperature zone and the low temperature zone, there are also multiple temperature transition zones, and the temperature transition zones are used to transition the temperature between the high temperature zone and the low temperature zone; the temperature values ​​of each temperature transition zone decrease in sequence from the high temperature zone to the low temperature zone; the temperature transition zone is provided with heat dissipation material, and the temperature value in the direction from the high temperature zone to the low temperature zone changes linearly in a step-like manner; wherein the temperature value change rate k1 of the temperature value transition zone is less than the temperature value change rate k2 of the low temperature zone.

2. The photovoltaic module manufacturing process according to claim 1, characterized in that: The temperature value of the target point and the distance between the target point and the high temperature zone change linearly, and the temperature value change rate ranges from -10°C / mm to -5°C / mm; wherein the position of the target point is any point outside the high temperature zone of the solar cell.

3. The photovoltaic module manufacturing process according to claim 1, characterized in that: The temperature transition zone includes a first temperature transition zone and a second temperature transition zone; the first temperature transition zone and the second temperature transition zone have different heat dissipation materials; The temperature change rate k2 in the low temperature zone ranges from -3°C / mm to -2°C / mm; the temperature change rate k3 in the first temperature transition zone ranges from -10°C / mm to -8°C / mm; the temperature change rate k4 in the second temperature transition zone ranges from -5°C / mm to -3°C / mm.

4. The photovoltaic module manufacturing process according to claim 1, characterized in that: The temperature difference between the high temperature zone and the low temperature zone ranges from 250°C to 10°C.

5. The photovoltaic module manufacturing process according to claim 1, characterized in that: The value range of the high temperature zone width d is 150 mm to 185 mm.

6. The photovoltaic module manufacturing process according to claim 1, characterized in that: The low temperature zone width value D is equal to the width value of the solar cell; and the ratio of the high temperature zone width value d to the low temperature zone width value D is 85% to 95%.

7. The photovoltaic module manufacturing process according to claim 1, characterized in that: The width of each temperature transition zone is in the range of 2 mm to 6 mm; the temperature difference between adjacent temperature transition zones is in the range of 15° C. to 30° C.

8. The photovoltaic module manufacturing process according to claim 1, characterized in that: The high temperature zone includes a plurality of sub-high temperature zones; the sub-high temperature zone includes a zone where a row of grid lines are welded to the welding strip; or the sub-high temperature zone includes a zone where a column of grid lines are welded to the welding strip.

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