Preparation method of photovoltaic module and photovoltaic module

Abstract

The invention relates to a preparation method of a photovoltaic module and the photovoltaic module, which can prevent glue from shielding adjacent fine grid lines after a welding strip is pressed on each fine grid line, and the method comprises the following steps: respectively applying glue to a plurality of glue applying positions on a welding surface of a battery piece, the glue applying positions being arranged among the fine grid lines arranged along a first direction, the distance between every two adjacent fine grid lines is 1.05 mm to 1.13 mm, the thixotropic index Ti of the glue is 2.4 to 3.2, and the gluing width is 0.4 mm to 0.52 mm; a welding strip is stacked on the welding face and located on the glue, the length direction of the welding strip is in the first direction, the width direction of the welding strip is perpendicular to the first direction, the thickness direction of the welding strip is perpendicular to the battery piece, and the width of the welding strip ranges from 0.2 mm to 0.26 mm; a welding strip is pressed on the fine grid lines through a pressing tool; the glue is solidified; and welding a welding strip to each fine grid line.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a method for preparing a photovoltaic module and a photovoltaic module. Background Art

[0002] Conventional photovoltaic solar modules use screen printing and other methods to deposit silver on the surface of photovoltaic solar cells to form conductive grid lines, and then print the main grid and pad points at designated locations, and then use high-temperature welding to alloy the welding strips and PAD points, and weld the busbars to connect the cells in series to form photovoltaic modules. Due to the large size of the main grid and PAD points of conventional cells, the effective area of ​​photoelectric conversion is reduced, reducing the power generation efficiency; and the large loss of silver paste results in high production costs, which seriously restricts the development of solar photovoltaic modules.

[0003] For this reason, a busbar-free cell has been launched on the market. The cell surface does not have a busbar, but only prints fine busbars on the surface, which are directly connected to the fine busbars on the cell using solder strips. The fine busbars will not block the effective area of ​​light energy conversion, and reduce silver paste loss, truly increasing efficiency and reducing costs.

[0004] There are currently two ways to print busbar-free solar cells: 1. Print glue first and then cover with solder wire; 2. Cover with solder wire first and then print glue. These two printing methods have their own advantages and disadvantages: Printing glue first and then covering with solder wire can save silver paste consumption and effectively prevent the solder wire from moving during the lamination process; but the solder wire is wrapped to a small extent, resulting in lower tension. Covering with solder wire first and then printing glue does not need to consider calendering issues, but the large loss of silver paste leads to increased costs. Summary of the invention

[0005] Based on this, it is necessary to provide a method for preparing a photovoltaic module to solve the above problems. A photovoltaic module is also provided.

[0006] A method for preparing a photovoltaic module comprises: applying glue to a plurality of glue application positions on a welding surface of a battery cell, the glue application positions being arranged between fine grid lines arranged along a first direction, the spacing between two adjacent fine grid lines being 1.05 mm-1.13 mm, the thixotropic index Ti of the glue being 2.4-3.2, and the glue application width being 0.4 mm-0.52 mm; stacking a welding strip on the welding surface and being located on the glue, the length direction of the welding strip being along the first direction, the width direction of the welding strip being perpendicular to the first direction, the thickness direction of the welding strip being perpendicular to the battery cell, and the width of the welding strip being 0.2 mm-0.26 mm; pressing the welding strip to each of the fine grid lines by using a pressing tool; curing the glue; and welding the welding strip to each of the fine grid lines.

[0007] In some embodiments, the welding surface is the back side of the battery cell, or the welding surface is the front side and the back side of the battery cell.

[0008] In some embodiments, the distance between two adjacent fine grid lines is 1.13 mm, the thixotropic index Ti of the glue is 2.4, the glue application width is 400 μm-430 μm, and the width of the welding strip is 0.26 mm.

[0009] In some embodiments, in the first direction, the amount of glue applied at two glue application locations at both ends of the battery cell is greater than the amount of glue applied at the remaining glue application locations.

[0010] In some embodiments, the glue application position is glued by inkjet, silk screen printing or glue dispensing.

[0011] In some embodiments, after the soldering ribbon is pressed onto the battery cell using a pressing tool, the width of the glue is less than 0.7 mm.

[0012] In some embodiments, in the thickness direction of the solder strip, the top surface of the glue is lower than the top surface of the solder strip, and 40%-80% of the solder strip is wrapped by the glue.

[0013] In some embodiments, the solder strip is pressed against each of the fine grid lines using a pressing tool, comprising: pressing the solder strip using a pressing needle of the pressing tool to provide pressure so that the solder strip is directed toward the battery cell, wherein the pressure provided by two of the pressing needles at both ends in the first direction is less than the pressure provided by the remaining pressing needles.

[0014] In some embodiments, the length of the two pressing pins at both ends in the first direction is greater than the length of the remaining pressing pins; or the pressing pins are elastically connected to the clamping tooling through elastic parts, and the compression amount of the two elastic parts at both ends in the first direction is greater than the compression amount of the remaining elastic parts.

[0015] A photovoltaic module is prepared by the method.

[0016] In the present application, for the spacing between two adjacent fine grid lines of 1.05mm-1.13mm, glue with a thixotropic index Ti of 2.4-3.2 is selected, and the glue application width is controlled between 0.4mm-0.52mm. The width of the soldering tape used in combination is 0.2mm-0.26mm. This ensures that after the soldering tape is pressed against each of the fine grid lines, the glue will not shield the adjacent fine grid lines after flowing, thereby ensuring the power of the photovoltaic module; and the degree of glue wrapping the soldering tape within the range of 40%-80% can meet the glue tension requirement for the soldering tape, and there is no need to wrap the entire soldering tape with glue, thereby reducing the amount of glue used. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a schematic diagram of a glue application site on a main grid-less solar cell in a photovoltaic module according to an embodiment of the present application.

[0018] FIG. 2 is a schematic diagram of glue application locations on some main grid cells in a photovoltaic module according to an embodiment of the present application.

[0019] FIG. 3 is a schematic structural diagram of a clamping tool according to an embodiment of the present application.

[0020] FIG. 4 is a flow chart of a method for preparing a photovoltaic module according to an embodiment of the present application.

[0021] FIG. 5 is a diagram showing the effect of the cell sheets in the photovoltaic module of an embodiment of the present application before glue calendering.

[0022] FIG. 6 is a diagram showing the effect of glue pressing of the cell sheets in the photovoltaic module according to an embodiment of the present application.

[0023] FIG. 7 is a schematic diagram of 40% welding wire wrapped with glue in the photovoltaic module of the present application.

[0024] FIG8 is a schematic diagram of 60% welding wire wrapped with glue in the photovoltaic module of the present application.

[0025] FIG. 9 is a schematic diagram of 80% of the welding wire wrapped with glue in the photovoltaic module of the present application.

[0026] Fig.10 This is a partial interface diagram of the photovoltaic module of the present application, in which the glue wraps 60% of the welding wire.

[0027] Reference numerals:

[0028] 10. Battery cell; 110. Welding surface; 120. Fine grid line; 130. Gluing position; 140. Glue; 150. Welding strip; 160. Main grid line; 20. Pressing tool; 210. Mounting seat; 220. Pressing needle; 230. Elastic part; 240. Limiting structure. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0030] In the description of the present application, it should be understood that if the 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. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply 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 on the present application.

[0031] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0032] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0033] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0034] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0035] As mentioned above, when it is necessary to use the solder strip to directly connect with the fine grid lines (also known as the secondary grid lines) on the battery cell, if the method of printing glue first and then covering the solder wire is adopted, the amount of glue can be saved and the solder wire can be effectively prevented from moving during the lamination process; however, the degree of wrapping of the solder wire is small, resulting in low tension. If the amount of glue applied is increased to ensure the tension, the degree of wrapping of the solder wire increases after the glue is rolled over the solder wire, but the glue is easily blocked by the adjacent fine grid lines after being rolled.

[0036] In view of the above contradiction, the present application proposes a method for preparing a photovoltaic module, which can save glue and avoid the glue from easily blocking adjacent fine grid lines after calendering. To facilitate understanding of the present application, the architecture of the photovoltaic module involved in the present application is first described.

[0037] Referring to FIG. 1 , the photovoltaic module involved in the present application includes at least one battery string. The battery string includes at least one battery cell 10. Among them, FIG. 1 only schematically shows one battery cell 10. A plurality of fine grid lines 120 arranged along a first direction X are provided on the welding surface 110 of each battery cell 10. The gaps between adjacent fine grid lines 120 are glue application positions 130 for applying glue 140.

[0038] Optionally, as shown in FIG. 1 , the cell 10 in the present application may be a busbar-less cell; in this case, glue may be applied between adjacent thin grid lines 120 .

[0039] Optionally, as shown in FIG2 , the battery cell 10 is provided with a plurality of main grid lines 160 arranged at intervals along the second direction Y. The length direction of the main grid lines 160 is perpendicular to the thin grid lines 120. At this time, the position of the main grid lines 160 is avoided when applying glue. For example, as shown in FIG2 , the battery cell 10 is provided with two main grid lines arranged at intervals along the second direction Y. In the second direction Y, a plurality of glue areas are formed between the two main grid lines 160 along the first direction X.

[0040] The arrangement direction of the plurality of cells 10 in the cell string may be the same as or perpendicular to the first direction X. This embodiment does not limit the structure of the cell, and the types of cells include but are not limited to Passivated Emitter Rear Cell (PERC), Tunnel Oxide Passivated Contact (TOPCon), Heterojunction with Intrinsic Thin-film (HJT), Interdigitated Back Contact (IBC), Perovskite Cell, etc.

[0041] Referring to FIG3 , the method for preparing a photovoltaic module provided in the present application comprises the following steps:

[0042] S100, glue 140 is applied to multiple glue application positions 130 on the welding surface 110 of the battery cell 10, wherein the glue application positions 130 are arranged between the fine grid lines 120 arranged along the first direction X, and the distance d between two adjacent fine grid lines 120 is 1.05mm-1.13mm. The thixotropic index Ti of the glue is 2.4-3.2, and the glue application width is 0.4mm-0.52mm.

[0043] In this step, glue 140 is applied to the multiple glue application positions 130 of the welding surface 110 of each battery cell 10, that is, glue is applied between adjacent thin grid lines 120. When applying glue to two adjacent thin grid lines 120, it is preferred to apply glue to the middle position.

[0044] The magnitude of the thixotropic index Ti of the glue 140 reflects the stability and fluidity of the glue 140 when subjected to force. The larger the thixotropic index, the less the degree of structural damage of the glue 140 after being subjected to force, showing higher stability and fluidity. The smaller the thixotropic index, the easier the structure is to be damaged after being subjected to force, showing poorer stability and fluidity.

[0045] The glue 140 is light-transmissive. Optionally, the light transmittance of the glue 140 is greater than or equal to 85%, which can reduce the light loss caused by the incident light being reflected by the surface of the cell, and can also ensure that more incident light is reflected to the surface of the cell for power generation, so as to effectively increase the power of the photovoltaic module.

[0046] The gluing width refers to the width of the glue 140 of adjacent fine grid lines 120 in the first direction X after gluing. In this step, the direction of the row is the first direction X, and the direction of the column is the second direction Y. After gluing, multiple rows and columns of glue areas are formed. In each row, the number of glue areas is at least one. Optionally, in each row, the gluing positions 130 between any two adjacent fine grid lines 120 are all glued to form continuously arranged glue areas. Optionally, in each row, glue is applied between two adjacent fine grid lines 120 at intervals to form discontinuous glue areas to save a certain amount of glue 140. Similarly, in each column, the number of gluing positions 130 is also at least one, and the formed glue areas are arranged continuously or arranged at intervals.

[0047] S200, overlap the soldering tape 150 on the soldering surface 110 and position it on the glue 140, wherein the length direction of the soldering tape 150 is along the first direction X, the width direction of the soldering tape 150 is perpendicular to the first direction X, the thickness direction of the soldering tape 150 is perpendicular to the battery cell, and the width of the soldering tape 150 is 0.2 mm-0.26 mm.

[0048] In the present application, the length direction of the soldering strip 150 is along the first direction X. The width direction of the soldering strip 150 is consistent with the length direction of the thin grid line 120, and both are along the second direction Y. It is easy to understand that the second direction Y is perpendicular to the first direction X. In the present application, along the second direction Y perpendicular to the first direction X, that is, the length direction of the thin grid line 120, a plurality of such soldering strips 150 may be provided.

[0049] The cross section of the soldering ribbon 150 may be circular, semicircular, elliptical, rectangular or triangular. This is not limited in the present application. When the cross section of the soldering ribbon 150 is circular, the width of the soldering ribbon 150 is the diameter of the soldering ribbon 150.

[0050] S300 , using a pressing tool 20 to press the soldering ribbon 150 onto each of the thin grid lines 120 .

[0051] In this step, referring to Figures 1 and 4, the welding ribbon 150 is pressed against each of the thin grid lines 120 using a pressing tool 20. This ensures that the welding ribbon 150 is tightly attached to the thin grid lines 120 on the corresponding battery cell 10, thereby ensuring that after welding, a high-quality alloy connection is formed between the welding ribbon 150 and the thin grid lines 120 to prevent cold welding.

[0052] Optionally, the pressing tool 20 includes a mounting seat 210 and a plurality of pressing pins 220 disposed on the mounting seat 210. The plurality of pressing pins 220 are arranged at intervals along the first direction X, and each pressing pin 220 corresponds to a thin grid line 120.

[0053] Furthermore, the pressing tool 20 is provided with multiple rows of pressing pins 220 in the second direction Y, and the pressing pins 220 in each row are arranged at intervals along the first direction X, and each pressing pin 220 corresponds to a thin grid line 120 , so that multiple positions of the thin grid lines on the welding surface 110 can be pressed simultaneously.

[0054] As shown in Figures 5 and 6, Figure 5 is a rendering before glue calendering. Figure 6 is a rendering after glue calendering, in which the solder strip is removed to show the effect after glue calendering. In Figures 5 and 6, the two upper and lower white lines parallel to each other are both fine grid lines, and the two fine grid lines are arranged along the up and down direction (i.e., the first direction X); there is glue between the two fine grid lines. It can be seen that after glue calendering, the width of the glue increases in the up and down direction, but the glue is still between the two fine grid lines and does not cover the fine grid lines.

[0055] S400, curing the glue 140. After curing, the solder strip 150 is fixed to the soldering surface 110 of the battery cell 10 by the cured glue 140. The glue 140 may be a heat curing glue or a light curing glue. The curing method may be heat curing or light irradiation curing.

[0056] S500, welding the welding strips 150 to the fine grid lines 120. For example, a laser welding device may be used to weld the welding strips 150 to the fine grid lines 120.

[0057] In the present application, for the spacing between two adjacent fine grid lines 120 of 1.05mm-1.13mm, a glue 140 with a thixotropic index Ti of 2.4-3.2 is selected, and the glue application width is controlled between 0.4mm-0.52mm. The width of the soldering tape 150 used in conjunction is 0.2mm-0.26mm. In this way, after the soldering tape 150 is pressed against each of the fine grid lines 120, the glue 140 will not shield the adjacent fine grid lines 120 after flowing, thereby ensuring the power of the photovoltaic module; and the degree of glue 140 wrapping the soldering tape 150 within the range of 40%-80% can meet the tensile force requirement of glue 140 on the soldering tape 150, and there is no need for glue to completely wrap the soldering tape 150, thereby reducing the amount of glue 140 used.

[0058] Furthermore, the method for preparing a photovoltaic module also includes the steps of respectively arranging a first adhesive film and a front plate, a second adhesive film and a back plate on both sides of the cell, and laminating, thereby forming a photovoltaic module including a front and back protection structure. Exemplarily, the second adhesive film is laid on the back plate. Then the cell is laid on the second adhesive film. Then the first adhesive film is laid on the cell, and the front plate is laid and laminated to the first adhesive film. Finally, the first adhesive film and the front plate, the second adhesive film and the back plate are laminated.

[0059] In some embodiments, the welding surface 110 is the back side of the battery cell 10, or the welding surface 110 is the front side and the back side of the battery cell 10. According to the setting of the welding surface, the battery cells are divided into two categories, wherein: the first category of battery cells has fine grid lines on both surfaces, that is, both surfaces are welding surfaces; the second category of battery cells has fine grid lines on only one surface, that is, only one surface is a welding surface.

[0060] In some embodiments, the distance between two adjacent thin grid lines is 1.13 mm, the thixotropic index Ti of the glue is 2.4, the glue application width is 400 μm-430 μm, and the width of the welding strip is 0.26 mm. Within the above range, the glue 140 blocks the surface of the photovoltaic module to a lesser extent.

[0061] In some embodiments, in the first direction X, the amount of glue applied at two glue application positions 130 at both ends of the battery cell 10 is greater than the amount of glue applied at the other glue application positions 130 .

[0062] In order to avoid false solder joints at the first and last glue application positions 130, in the present application, in the first direction X, the glue application amount at the first and last glue application positions 130 is relatively large, so that after the solder strip is compressed by the compression tool 20, the solder strip 150 is more tightly combined with the battery cell 10 at the first and last glue application positions 130, and the solder strip 150 can fit tightly with the first and last fine grid lines 120, thereby effectively avoiding false solder joints at the first and last ends of the solder strip during welding.

[0063] In some embodiments, inkjet, screen printing or dispensing is used to apply glue to the glue application position 130. The specific process of applying glue is not limited, as long as the glue within the aforementioned width range can be applied as required.

[0064] Optionally, the glue can be applied to the back or front side of the battery cell 10 by means of inkjet, screen printing or dispensing using a glue applying mechanism.

[0065] In some embodiments, after the soldering ribbon 150 is pressed onto the battery cell using the pressing tool 20 , the width of the glue is less than 0.7 mm.

[0066] In the present application, by controlling the amount of glue applied, the width of the glue is less than 0.7 mm after the soldering strip is pressed against the cell 10. In this way, on the one hand, the glue 140 has a better pulling force on the soldering strip 150, and on the other hand, the glue 140 has a lower degree of shielding on the surface of the cell, thereby ensuring the power of the photovoltaic module.

[0067] In some embodiments, in the thickness direction of the soldering tape 150 , the top surface of the glue 140 is lower than the top surface of the soldering tape 150 , and 40%-80% of the soldering tape 150 is wrapped by the glue 140 .

[0068] In the present application, after selecting the glue 140, the amount of glue applied is controlled so that 40%-80% of the solder strip 150 is wrapped by the glue 140. At this time, the top surface of the glue 140 is lower than the top surface of the solder strip 150, and the glue 140 does not wrap 100% of the solder strip.

[0069] Optionally, as shown in Fig. 7 , 40% of the soldering ribbon 150 is wrapped by the glue 140. As shown in Fig. 8 , 60% of the soldering ribbon 150 is wrapped by the glue 140. As shown in Fig. 9 , 80% of the soldering ribbon 150 is wrapped by the glue 140.

[0070] For further information, please refer to Fig.10 , Fig.10 A partial cross-sectional schematic diagram of a photovoltaic module is shown, in which 60% of the soldering ribbon is wrapped by glue 140 . Fig.10 In the figure, the number 1 refers to the object, which is glue. The cylindrical object above the glue is the welding strip. Above the welding strip is the encapsulation film in the photovoltaic module.

[0071] The tensile test verifies that when 40%-80% of the soldering ribbon 150 is wrapped by the glue 140, the fixing tensile force requirement of the soldering ribbon 150 in the photovoltaic module of the present application can be met, thereby saving the amount of glue 140 and reducing costs.

[0072] In some embodiments, step S300, using a pressing tool 20 to press the soldering ribbon 150 onto each of the thin grid lines 120, includes:

[0073] S310, using the pressing pins 220 of the pressing tool 20 to press the soldering ribbon 150 to provide pressure to make the soldering ribbon 150 face the battery cell 10, wherein the pressure provided by the two pressing pins 220 at both ends in the first direction X is less than the pressure provided by the remaining pressing pins 220.

[0074] In this embodiment, by making the pressure provided by the two pressing needles 220 at the two ends smaller than the pressure provided by the other pressing needles 220, when the welding strip 150 is pressed by the clamping tool 20, the pressing needles 220 at the two ends can give a greater pressure to the welding strip 150, and can ensure that the end of the welding strip 150 is pressed down, thereby preventing the end of the welding strip 150 from warping due to the height difference of a large amount of glue or other reasons, and then preventing the welding strip 150 in a warped state from being deformed, displaced or damaged by compression.

[0075] In some embodiments, the lengths of the two pressing pins 220 at the two ends in the first direction X are greater than the lengths of the remaining pressing pins 220 .

[0076] In this embodiment, the lengths of the two pressing pins 220 at both ends are set to be greater than the length of the pressing pin 220. In this way, when the pressing tool 20 is used to press the soldering ribbon 150, under the same stroke, the pressing pins 220 at both ends can give more pressure to the soldering ribbon 150, and can ensure that the ends of the soldering ribbon 150 are pressed down to prevent the ends of the soldering ribbon 150 from warping.

[0077] In some embodiments, referring to FIG. 4 , the pressing needle 220 is elastically connected to the pressing fixture 20 via an elastic member 230 , and the compression amount of the two elastic members 230 at both ends in the first direction is greater than the compression amount of the remaining elastic members 230 .

[0078] Optionally, the elastic member 230 is a spring, and the force applied by the pressing needle to the solder strip 150 is adjusted by adjusting the compression amount of the spring. The elastic force of the two springs at both ends is set to be greater than the elastic force of other springs, so that the pressure of the two pressing needles 220 at both ends in the first direction X is greater than the pressure of other pressing needles 220, which can ensure that the end of the solder strip 150 is pressed down to prevent the end of the solder strip 150 from warping.

[0079] Optionally, the clamping tool 20 includes a mounting seat 210, a pressing needle 220, an elastic member 230 and a limiting structure 240. The pressing needle 220 can be movably installed up and down in a mounting hole (not shown) of the mounting seat 210. The limiting structure 240 is arranged above the mounting seat 210 and cooperates with the pressing needle 220 to prevent the pressing needle 220 from falling out. The elastic member 2430 is sleeved on the pressing needle 220, and the two ends of the elastic member 230 are respectively abutted against the mounting seat 210 and the pressing needle 220, thereby realizing the movable installation of the pressing needle 220. At this time, the pressure of the pressing needle can be changed by adjusting the compression amount of the elastic member 230.

[0080] The advantages of the method for preparing the photovoltaic module of the embodiment of the present application are further illustrated in combination with Examples 1 to 12. The statistical results of Examples 1 to 12 are shown in Table 1.

[0081] Table 1

[0082] Specifically, in Examples 1-12, the glue application object of Examples 1-6 is the main grid-free battery cell of the structure shown in FIG1, and the glue application object of Examples 7-12 is the partial main grid battery cell of the structure shown in FIG2. Each Example is tested at least once, and the glue application width is controlled within the glue application width range of the Example. That is to say, when each Example is tested, the spacing between two adjacent fine grid lines, the thixotropic index Ti of the glue, and the width of the welding strip are determined, and the glue application width is allowed to fluctuate within a certain range, so that the process difficulty is not large and the operation is easy to implement.

[0083] For example, for Example 1, when the spacing between two adjacent fine grid lines is 1.13 mm, the thixotropic index Ti of the glue is 3.2, and the width of the solder strip is 0.26 mm. The glue width is 450-470 μm, and in 4 tests, the glue width can be, for example, 450 μm; 455 μm; 460 μm; 470 μm. In the 4 tests, the glue width after calendering is 0.57 mm, 0.58, 0.59 mm and 0.61 mm respectively. The operation methods of other embodiments are similar.

[0084] From the statistical results in Table 1, it can be seen that in each embodiment, the width of the rolled glue 140 is smaller than the spacing between adjacent fine grid lines, and the fine grid lines 120 are not covered. In addition, the tensile test verifies that the tensile force requirement of the glue on the welding strip is met, and the tensile force is not less than 0.1N.

[0085] Therefore, using the preparation method of the present application, when applying glue between fine grid lines within a certain spacing range, by selecting glue with a suitable thixotropic index and controlling the amount of glue applied, a solder strip of a suitable size is covered on the glue and pressed, and the rolled glue does not cover the fine grid lines, thereby ensuring that the degree of glue wrapping the solder strip is within the range of 40%-80% to meet the tension requirement of the glue on the solder strip, and there is no need to wrap the entire solder strip with glue, thereby reducing the amount of glue used.

[0086] The present application also provides a photovoltaic module, which is prepared by any of the methods described above. The photovoltaic module of the present application uses less glue and has sufficient tension on the welding strip, and the glue will not block the fine grid lines.

[0087] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for preparing a photovoltaic module, characterized in that: include: Apply glue to multiple glue application positions on the welding surface of the battery cell respectively, wherein the glue application positions are arranged between the fine grid lines arranged along the first direction, the spacing between two adjacent fine grid lines is 1.05mm-1.13mm, the thixotropic index Ti of the glue is 2.4-3.2, and the glue application width is 0.4mm-0.52mm; Stacking the welding strip on the welding surface and on the glue, the length direction of the welding strip is along the first direction, the width direction of the welding strip is perpendicular to the first direction, the thickness direction of the welding strip is perpendicular to the battery cell, and the width of the welding strip is 0.2mm-0.26mm; Using a pressing tool to press the welding strip onto each of the thin grid lines; curing the glue; The welding strip is welded to each of the thin grid lines.

2. The method according to claim 1, characterized in that: The welding surface is the back side of the battery cell, or the welding surface is the front side and the back side of the battery cell.

3. The method according to claim 1, characterized in that The distance between two adjacent fine grid lines is 1.13 mm, the thixotropic index Ti of the glue is 2.4, the glue application width is 400 μm-430 μm, and the width of the welding strip is 0.26 mm.

4. The method according to claim 1, characterized in that In the first direction, the glue application amount of the two glue application positions at both ends of the battery cell is greater than the glue application amount of the other glue application positions.

5. The method according to claim 1, characterized in that: The glue application position is glued by inkjet, silk screen printing or dispensing.

6. The method according to claim 1, characterized in that After the soldering ribbon is pressed onto the battery cell by the pressing tool, the width of the glue is less than 0.7 mm.

7. The method according to claim 1, characterized in that In the thickness direction of the solder strip, the top surface of the glue is lower than the top surface of the solder strip, and 40%-80% of the solder strip is wrapped by the glue.

8. The method according to claim 1, characterized in that: The method comprises: pressing the welding strip to each of the thin grid lines by using a pressing tool; The soldering ribbon is pressed by pressing pins of a pressing tool to provide pressure for the soldering ribbon to face the battery sheet, wherein the pressure provided by two pressing pins at two ends in a first direction is less than the pressure provided by the remaining pressing pins.

9. The method according to claim 8, characterized in that The lengths of the two pressing pins at both ends in the first direction are greater than the lengths of the remaining pressing pins; or the pressing pins are elastically connected to the pressing tooling through elastic parts, and the compression amount of the two elastic parts at both ends in the first direction is greater than the compression amount of the remaining elastic parts.

10. A photovoltaic module, characterized in that: The method is prepared by any one of claims 1 to 9.

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