Photovoltaic module manufacturing process

Abstract

The present application relates to the technical field of solar cells, and discloses a photovoltaic module manufacturing process, wherein the solar cell of the photovoltaic module includes a high temperature zone and a low temperature zone; wherein the high temperature zone is the area where the grid lines of the solar cell are welded to the welding strips; the low temperature zone is the edge area of ​​the solar cell; and the heating temperature value of the high temperature zone is greater than the heating temperature value of the low temperature zone. The problem that traditional overall heating is difficult to take into account the difference in heat demand of different parts of the cell during welding is solved. In the present application, zone heating can set different temperatures according to the characteristics of each area, avoiding different expansion coefficients of different materials that lead to different degrees of contraction under high temperature heating conditions, thereby reducing uneven thermal stress, reducing the risk of cell warping, ensuring welding quality, and maintaining the stability of the cell structure, which is conducive to improving the yield of the photovoltaic module formed after lamination.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a photovoltaic module manufacturing process. Background Art

[0002] In today's booming solar energy industry, solar cells, as core components, have attracted much attention for their manufacturing process. Among them, the technical maturity of solar cells in the welding stage has a key impact on the performance and yield of the cells. At present, the problem of welding warpage is more prominent in the welding process of solar cells.

[0003] From a microscopic perspective, due to the difference in thermal expansion coefficients between silicon and the soldering ribbon, the expansion coefficient of the soldering ribbon is greater than that of silicon. During the shrinkage process after welding, the soldering ribbon shrinks more than the silicon. This difference in shrinkage will cause the cell to warp. At the same time, in actual welding operations, because the welding temperature is relatively high, taking the common light box heating welding as an example, the light box temperature can reach 300°C. Such a high temperature will cause the outer edge area of ​​the photovoltaic cell to warp due to uneven heating. The negative impact of this warping cannot be underestimated. It will not only cause poor connection between the soldering ribbon and the soldering wire, but also affect the conductivity of the battery, thereby reducing the power generation efficiency of the solar cell; in severe cases, it will also cause the battery to break, directly causing the product to be scrapped, greatly increasing production costs and reducing production benefits. This series of problems urgently needs to be solved through innovative welding technology or process improvements. Summary of the invention

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

[0005] To solve the above technical problems, an embodiment of the present application provides a photovoltaic module manufacturing process, wherein the photovoltaic module includes a solar cell and a welding strip; the solar cell is printed with a grid line, and the grid line is used to be welded with the welding strip; the solar cell includes a high temperature zone and a low temperature zone; wherein the high temperature zone is an area including the grid line of the solar cell and the welding strip for welding; the low temperature zone is an 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.

[0006] In the embodiment of the present application, the solar cell is heated in different zones, and the area where the grid lines and welding strips need to be welded is used as the high temperature zone, and the edge area of ​​the cell is used as the low temperature zone for heating at different temperatures. This allows the temperature of different areas of the solar cell to be precisely controlled during the welding process. This solves the problem that traditional overall heating is difficult to take into account the differences in heat requirements of different parts of the cell during welding. In the present application, zone heating can set different temperatures according to the characteristics of each area, avoiding different expansion coefficients of different materials that lead to different degrees of shrinkage under high temperature heating conditions, thereby reducing uneven thermal stress, reducing the risk of cell warping, ensuring welding quality, and maintaining the stability of the cell structure, which is beneficial to improving the yield of photovoltaic modules formed after lamination.

[0007] In addition, 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.

[0008] In addition, 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 value of each temperature transition zone decreases in sequence from the high temperature zone to the low temperature zone.

[0009] In addition, the temperature transition zone is provided with heat dissipation material, and the temperature value 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.

[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 temperature value change rate k2 of the low temperature zone ranges from -3°C / mm to -2°C / mm; the temperature value change rate k3 of the first temperature transition zone ranges from -10°C / mm to -8°C / mm; the temperature value change rate k4 of the second temperature transition zone ranges from -5°C / mm to -3°C / mm.

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

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

[0013] In addition, 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%-95%.

[0014] In addition, 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.

[0015] In addition, 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0017] Figure 1 It is a schematic diagram of the structure of a photovoltaic module of a photovoltaic module production process provided in one embodiment of the present application; Figure 2 is a schematic structural diagram of a photovoltaic module according to a photovoltaic module production process provided by another embodiment of the present application; Figure 3 It is a partial structural schematic diagram of a photovoltaic module of a photovoltaic module production process provided by an embodiment of the present application; Figure 4 is a curve diagram showing the relationship between the temperature value of a target point and the distance between the target point and the high temperature zone in one embodiment of the present application; Figure 5 is a schematic diagram of a partial structure of a photovoltaic module of a photovoltaic module production process provided by another embodiment of the present application; Figure 6 is a curve diagram showing the relationship between the temperature value of a target point and the distance between the target point and the high temperature zone in another embodiment of the present application; Figure 7 This is a flow chart of a photovoltaic module welding method provided in one embodiment of the present application. DETAILED DESCRIPTION

[0018] Due to the difference in thermal expansion coefficients between silicon and the soldering ribbon, the expansion coefficient of the soldering ribbon is greater than that of silicon. During the shrinkage process after welding, the shrinkage degree of the soldering ribbon is greater than that of silicon. This difference in shrinkage degree will cause the battery cell to warp.

[0019] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in the present application, many technical details are proposed in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can also be implemented. The division of the following embodiments is for the convenience of description, and the specific implementation of the present application should not be construed as any limitation, and the various embodiments can be combined and referenced with each other under the premise of no contradiction.

[0020] One embodiment of the present application relates to a photovoltaic module manufacturing process, which can be applied to the production process of solar cells that need to be heated and welded, such as monocrystalline silicon solar cells, polycrystalline silicon solar cells, thin-film solar cells and perovskite solar cells, back contact (BC) cells, tunnel oxide passivated contact (TOPCON) cells and emitter back passivation (PERC) cells. The photovoltaic module includes a solar cell and a welding strip; the solar cell is printed with a grid line, and the grid line is used to weld with the welding strip; the solar cell includes a high temperature zone and a low temperature zone; wherein the high temperature zone is the area where the grid line of the solar cell is welded with the welding strip; the low temperature zone 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. This application heats the solar cell by partitioning, and uses the area where the grid lines and welding strips need to be welded as the high-temperature area, and the edge area of ​​the cell as the low-temperature area for partitioning and heating at different temperatures, so that during the welding process, the temperature of different areas of the solar cell can be precisely controlled; it solves the problem that traditional overall heating is difficult to take into account the difference in heat demand of different parts of the cell during welding. In this application, the partition heating can set different temperatures according to the characteristics of each area to avoid different expansion coefficients of different materials and different shrinkage degrees under high-temperature heating conditions, thereby reducing uneven thermal stress, reducing the risk of cell warping, ensuring welding quality, and maintaining the stability of the cell structure. The following is a specific description of the implementation details of the photovoltaic module manufacturing process of the embodiment of the present application. The following content is only the implementation details provided for the convenience of understanding and is not necessary for the implementation of this solution.

[0021] like Figure 1 As shown, the photovoltaic module includes a solar cell 1 and a welding ribbon 2; the solar cell 1 is printed with a grid line, and the grid line is used to be welded with the welding ribbon; Figure 2As shown, the solar cell 1 includes a high temperature zone 101 and a low temperature zone 102; wherein the high temperature zone is a region where the grid lines of the solar cell are welded to the welding strips; the low temperature zone 102 is an edge region of the solar cell 1; the heating temperature value of the high temperature zone 101 is greater than the heating temperature value of the low temperature zone 102.

[0022] In some embodiments, the width d of the high temperature zone 101 ranges from 150 mm to 185 mm. Furthermore, in order to avoid warping of the battery cells in the low temperature zone 102 and ensure a good welding effect of the welding ribbon 2 and the battery cells in a larger area, the width d of the high temperature zone 101 is controlled in the range of 160 mm to 170 mm; for example, the width d of the high temperature zone 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 zone 101 according to actual production requirements, and this application does not limit this.

[0023] In other embodiments, the width value D of the low temperature zone 102 is equal to the width value of the solar cell 1; and the ratio of the width value d of the high temperature zone 101 to the width value D of the low temperature zone 102 is 85% to 95%. Further, the ratio of the width d of the high temperature zone 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 zone 101 to the width D of the cell is 93%, if the width of the cell is 172mm, the width value of the high temperature zone 101 is 160mm; when the ratio of the width d of the high temperature zone 101 to the width D of the cell is 87.5%, if the width of the cell is 195mm, the width value of the high temperature zone 101 is 170mm. 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 zone 101 to the width D of the cell according to actual production requirements, and this application does not limit it here.

[0024] Specifically, the low temperature zone 102 is the edge area of ​​the solar cell 1, and the low temperature zone 102 can be divided into an area that maintains a preset edge distance from the edge of the solar cell 1; in order to ensure that the low temperature zone 102 does not overlap with the high temperature zone 101, the preset edge distance L is ≤ (the width D of the cell-the width d of the high temperature zone) / 2.

[0025] In some embodiments, the temperature difference between the high temperature zone 101 and the low temperature zone 102 ranges from 250°C to 10°C. Furthermore, the temperature difference between the high temperature zone 101 and the low temperature zone 102 ranges from 150°C to 50°C. During the welding process, the high temperature zone 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 temperature of other areas is set to be lower than the temperature of the high temperature zone 101. In some specific embodiments, the lowest welding temperature designed for the edge of the low temperature zone 102 is 150°C, and the welding temperature of the high temperature zone 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 zone 101 according to actual production requirements, and this application does not limit it here.

[0026] Furthermore, if Figure 3 As shown, in some embodiments, between the high temperature zone 101 and the low temperature zone 102, there are also multiple temperature transition zones, and the temperature transition zones are used to transition the temperature between the high temperature zone 101 and the low temperature zone 102; the temperature values ​​of each temperature transition zone decrease in sequence from the high temperature zone 101 to the low temperature zone 102. The low temperature zone 102 and the temperature transition zone can be regarded as the areas of the cell that are prone to warping due to high temperature during the welding stage, except for the areas that require high temperature welding; wherein the low temperature zone 102 is closer to the edge area of ​​the solar cell 1; and the temperature transition zone is the area between the high temperature zone 101 and the low temperature zone 102.

[0027] In some embodiments, the width of each temperature transition zone ranges from 2 mm to 6 mm; the temperature difference between adjacent temperature transition zones is 15°C to 30°C. Specifically, when the same heat dissipation material is used between adjacent temperature transition zones, the temperature difference between the temperature transition zones is 15°C to 30°C. In some specific embodiments, the width of each temperature transition zone is 3 mm, and the average temperature of each temperature transition zone is regarded as the temperature of the temperature transition zone.

[0028] like Figure 4 As shown, Figure 4 The horizontal axis is the distance x between the target point and the high temperature zone 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 zone 101 of the solar cell 1. The temperature value of the target point and the distance between the target point and the high temperature zone 101 change linearly, and the temperature value change rate ranges from -10℃ / mm to -5℃ / 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 zone 101, is Figure 4The slope k of the temperature change curve of the target point in the middle. Since the temperature gradually decreases in the direction away from the high temperature zone, the value of k is a value less than 0. When the target point moves away from the high temperature zone 101 along a certain straight line from the edge of the high temperature zone 101 to the edge of the battery cell, the temperature drops by a preset amplitude for each preset distance away from the high temperature zone 101. Specifically, the change law of the temperature y of the target point with the distance x between the target point and the high temperature zone 101 satisfies the following equation:

[0029] Wherein, k is the rate of change of the temperature value, -10°C / mm≤k≤-5°C / mm, and T is the welding temperature of the high temperature zone 101. For example, in one embodiment, the value of k is -7.5°C / mm, and the welding temperature of the high temperature zone 101 is 270°C. Then, the temperature y of the target point changes with the distance x between the target point and the high temperature zone 101 as y=-7.5x+270. Under this heating condition, the temperature of the target point decreases by 22.5°C for every 3mm the target point moves away from the high temperature zone. In another embodiment, the value of k is -5°C / mm, and the welding temperature of the high temperature zone 101 is 300°C. Then, the temperature y of the target point changes with the distance x between the target point and the high temperature zone 101 as y=-5x+300. Under this heating condition, the temperature of the target point decreases by 15°C for every 5mm the target point moves away from the high temperature zone. It should be noted that T is the welding temperature of the high temperature zone 101. During the welding process, the welding temperature of the high temperature zone 101 remains constant. Those skilled in the art can adjust the specific value or value range of the welding temperature and the temperature value change rate of the high temperature zone 101 according to actual production requirements, and this application does not limit this.

[0030] Specifically, due to the complex heating conditions and heating environment, various effects will be produced on the actual heating temperature. Further temperature control settings can be used to ensure that the temperature value of the target point and the distance between the target point and the high temperature zone 101 change linearly. First, a special design is made for the heating plate: a high-density heating wire or heating element is arranged in the middle area, and the distribution density of the heating wire or element is reduced in the surrounding area; a heating plate material with non-uniform thermal conductivity is used, the middle part uses a material with good thermal conductivity, such as a high-purity metal thermal conductive material, and the surrounding part uses a material with relatively poor thermal conductivity, such as ceramic or alloy with low thermal conductivity. Alternatively, a heating system with independent temperature control in multiple regions is used: different heating areas are equipped with independent temperature sensors and heating controllers; the heating equipment uses multiple heating lamps or heating modules, which are distributed above the battery cell at different angles and positions. Second, adjust the heating process: make different control adjustments to the heating time and heating speed of different areas; or change the heating environment pressure of different areas during the heating process. Third, set auxiliary tools or materials for heat conduction, and place heat conduction blocks with special shapes, such as wedge-shaped heat conduction blocks. It should be noted that those skilled in the art can adjust the specific method of temperature control according to actual production requirements to maintain a linear change in temperature values, and this application does not impose any limitation thereto.

[0031] In other embodiments, the temperature transition zone is provided with a heat dissipation material, and the temperature value in the direction from the high temperature zone 101 to the low temperature zone 102 changes linearly in a step-like manner. Among them, the temperature value change rate k1 of the temperature transition zone is less than the temperature value change rate k2 of the low temperature zone 102. The temperature value change rate k1 of the temperature transition zone is the ratio of the temperature value of the target point in the temperature transition zone to the distance between the target point and the high temperature zone 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 zone 102 is the ratio of the temperature value of the target point in the low temperature zone 102 to the distance between the target point and the high temperature zone 101, that is, the slope k2 of the temperature change curve of the target point; since heat dissipation material is added in the temperature transition zone, the temperature change amplitude in the temperature transition zone is larger, so k1<k2.

[0032] Specifically, during the welding heating process, a heat-absorbing heat-conducting material is arranged near the temperature transition zone, so that the temperature transition zone can dissipate more heat and quickly reduce the temperature. Figure 5As shown, 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. 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. From the high temperature zone 101 to the low temperature zone 102, they are the high temperature zone 101, the first temperature transition zone, the second temperature transition zone and the low temperature zone 102, respectively. 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 needs, or set a third temperature transition zone, etc., and this application does not limit this.

[0033] 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 is less than 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 amplitude 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 amplitude 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 method of the specific heat dissipation material 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 it here.

[0034] In the case where the temperature value change rate k3 of the first temperature transition zone is less than 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 is less than the temperature value change rate k4 of the second temperature transition zone and less than the temperature value change rate k2 of the low temperature zone. The temperature value change rate k2 of the low temperature zone has a value range of -3°C / mm to -2°C / mm; the temperature value change rate k3 of the first temperature transition zone has a value range of -10°C / mm to -8°C / mm; the temperature value change rate k4 of the second temperature transition zone has a value range of -5°C / mm to -3°C / mm.

[0035] The variation rule of the temperature y1 of the first target point in the first temperature transition zone with the distance x1 between the target point and the high temperature zone 101 satisfies the following equation:

[0036] Wherein, 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 .

[0037] The variation rule of the temperature y2 of the second target point in the second temperature transition zone with the distance x2 between the target point and the high temperature zone 101 satisfies the following equation:

[0038] Among them, x2≥x1, k4 is the temperature value change rate of the second temperature transition zone, -5℃ / mm≤k4≤-3℃ / mm, y1' is the temperature at the junction of the first temperature transition zone and the second temperature transition zone, that is, the position corresponding to the temperature value y1' is the farthest position from the high temperature zone 101 in the first temperature transition zone, and is also the closest position to the high temperature zone 101 in the second temperature transition zone.

[0039] The variation rule of the temperature y3 of the third target point in the low temperature zone 102 with the distance x3 between the target point and the high temperature zone 101 satisfies the following equation:

[0040] Among them, x3≥x2, k2 is the temperature value change rate of the first temperature transition zone, -3℃ / mm≤k2≤-2℃ / mm, y2' is the temperature at the junction of the second temperature transition zone and the low temperature zone 102, that is, the position corresponding to the temperature value y2' is the farthest position from the high temperature zone 101 in the second temperature transition zone, and is also the closest position to the high temperature zone 101 in the low temperature zone 102.

[0041] Specifically, in one embodiment, the temperature value change rate k2 of the low temperature zone is -9°C / mm; the temperature value change rate k3 of the first temperature transition zone is -9°C / mm; the temperature value change rate k4 of the second temperature transition zone is -4°C / mm. Since the temperature value change rate k3 of the first temperature transition zone is different from the temperature value change rate k4 of the second temperature transition zone, Figure 6 In the experiment, the temperature changes linearly in a step-like manner.

[0042] In some embodiments, the high temperature zone 101 includes a plurality of sub-high temperature zones; the sub-high temperature zone includes an area where a row of grid lines are welded to the welding strip; or the sub-high temperature zone includes an area where a column of grid lines are welded to the welding strip. Further, the sub-high temperature zone can also be a single welding point area. It should be noted that those skilled in the art can flexibly adjust the scope of the sub-high temperature zone according to actual application requirements, and the present application is not limited thereto. Further, the scope of the high temperature zone can be determined based on the outermost multiple sub-high temperature zones in the sub-high temperature zone.

[0043] In the embodiment of the present application, the solar cell is heated in different zones, and the area where the grid lines and welding strips need to be welded is used as the high temperature zone, and the edge area of ​​the cell is used as the low temperature zone for heating at different temperatures. This allows the temperature of different areas of the solar cell to be precisely controlled during the welding process. This solves the problem that traditional overall heating is difficult to take into account the differences in heat requirements of different parts of the cell during welding. In the present application, zone heating can set different temperatures according to the characteristics of each area, avoiding different expansion coefficients of different materials that lead to different degrees of shrinkage under high temperature heating conditions, thereby reducing uneven thermal stress, reducing the risk of cell warping, ensuring welding quality, and maintaining the stability of the cell structure, which is beneficial to improving the yield of photovoltaic modules formed after lamination.

[0044] 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 and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the protection scope of this application; adding insignificant modifications to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the protection scope of this application.

[0045] In addition, the examples mentioned in the above embodiments can be freely combined, and any combination can be understood as an embodiment. The "embodiment" or "example" appearing in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It can be understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0046] 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 described in the claims can be combined in different ways and still achieve the desired results. In addition, the structures depicted in the drawings do not necessarily require the specific order or sequential order shown to achieve the desired results.

[0047] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the term "plurality" refers to more than two (including two), unless otherwise clearly and specifically defined.

[0048] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0049] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0050] In the description of the embodiments of the present application, features (e.g., regions, structures, devices) described as being "adjacent" to each other mean and include features with one or more disclosed identifiers that are positioned closest to each other (e.g., closest). Additional features (e.g., additional regions, additional structures, additional devices) that do not match one or more disclosed identifiers of the "adjacent" features may be placed between the "adjacent" features. In other words, the "adjacent" features may be positioned directly adjacent to each other so that no other features intervene between the "adjacent" features; or the "adjacent" features may be positioned indirectly adjacent to each other so that at least one feature with an identifier other than an identifier associated with at least one "adjacent" feature is positioned between the "adjacent" features.

[0051] As used herein, "thermal conductive material" means and includes, for example, one or more of the following thermal conductive materials: 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 and can accurately control heat transfer to ensure welding quality; thermal conductive silicone helps to enhance heat conduction and prevent local overheating during welding from damaging the battery; and ceramics like boron nitride, with its excellent thermal conductivity and insulation properties, can be used as an isolation and thermal conductive material for solar cells during welding to ensure stable welding work. In addition, "heat dissipation material" means and includes a structure formed by and including a thermal conductive material.

[0052] Another embodiment of the present application relates to a photovoltaic module welding method, such as Figure 7 As shown, including: Step 701, dividing the solar cell into a high temperature zone and a low temperature zone according to the welding area of ​​the solar cell and the welding ribbon, wherein the high temperature zone is a zone including the grid line of the solar cell and the welding ribbon for welding; the low temperature zone is an edge zone of the solar cell; and the heating temperature value of the high temperature zone is greater than the heating temperature value of the low temperature zone; Step 702, performing zone-by-zone welding heating on the high temperature zone according to the preset temperature value corresponding to the high temperature zone; and performing zone-by-zone welding heating on the low temperature zone according to the heating temperature value of the low temperature zone.

[0053] In some embodiments, between the high temperature zone and the low temperature zone, there are also multiple temperature transition zones, 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 from the high temperature zone to the low temperature zone changes linearly in a step-like manner. Correspondingly, when multiple temperature transition zones are provided, the method further includes: performing zoned welding heating on the high temperature zone according to the preset temperature values ​​corresponding to the temperature transition zones.

[0054] In the embodiment of the present application, the solar cell is heated in different zones, and the area where the grid lines and welding strips need to be welded is used as the high temperature zone, and the edge area of ​​the cell is used as the low temperature zone for heating at different temperatures. This allows the temperature of different areas of the solar cell to be precisely controlled during the welding process. This solves the problem that traditional overall heating is difficult to take into account the differences in heat requirements of different parts of the cell during welding. In the present application, zone heating can set different temperatures according to the characteristics of each area, avoiding different expansion coefficients of different materials that lead to different degrees of shrinkage under high temperature heating conditions, thereby reducing uneven thermal stress, reducing the risk of cell warping, ensuring welding quality, and maintaining the stability of the cell structure, which is beneficial to improving the yield of photovoltaic modules formed after lamination.

[0055] 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 conjunction with the above method embodiment. The relevant technical details mentioned in the above method embodiment are still valid in this embodiment, and in order to reduce repetition, they are not repeated here. Accordingly, the relevant technical details mentioned in this embodiment can also be applied in the above method embodiment.

[0056] Those skilled in the art will appreciate that the above embodiments are specific embodiments for implementing the present application, and in actual applications, various changes may be made thereto in form and detail 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.

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: A plurality of temperature transition zones are further included between the high temperature zone and the low temperature zone, 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 of the temperature transition zones decrease in sequence from the high temperature zone to the low temperature zone.

4. The photovoltaic module manufacturing process according to claim 3, characterized in that: The temperature transition zone is provided with heat dissipation material, and the temperature value 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.

5. The photovoltaic module manufacturing process according to claim 4, 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.

6. 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.

7. 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.

8. 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%.

9. The photovoltaic module manufacturing process according to claim 3, 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.

10. 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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