Method for manufacturing a photovoltaic module and photovoltaic module

Abstract

The application relates to a preparation method of a photovoltaic module and the photovoltaic module, which can avoid that glue shields adjacent fine grid lines after the welding strip is pressed on each fine grid line. The method comprises the following steps: respectively applying glue to multiple glue applying positions on a welding surface of a cell piece, the glue applying positions are arranged between fine grid lines arranged along a first direction, the interval between two adjacent fine grid lines is 1.05mm-1.13mm, the thixotropy index Ti of the glue is 2.4-3.2, and the glue applying 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 cell piece, and the width of the welding strip is 0.2mm-0.26mm; pressing the welding strip on each fine grid line by using a pressing tool; curing the glue; and welding the welding strip to each fine grid line.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic technology, in particular to a preparation method of a photovoltaic module and the photovoltaic module. BACKGROUND

[0002] A conventional photovoltaic solar module is prepared by screen printing silver on the surface of a solar cell to form conductive grid lines, printing main grid and Pad points at specified positions, and then alloying solder strips and PAD points by high-temperature welding, and connecting the solar cells in series by soldering bus bars to form a photovoltaic module. Since the size of the main grid and PAD points of the conventional solar cell is large, the effective area for photoelectric conversion is reduced, and the power generation efficiency is lowered. In addition, the silver paste is consumed in large quantities, resulting in high production cost, which seriously restricts the development of solar photovoltaic modules.

[0003] Therefore, a main-grid-free solar cell is introduced in the market. The surface of the solar cell is not provided with main grid lines, but only with fine grid lines, and the solder strip is directly connected to the fine grid lines on the solar cell. The fine grid lines neither block the effective area for light energy conversion nor reduce the consumption of silver paste, and truly increase efficiency and reduce cost.

[0004] Currently, there are two printing methods for the main-grid-free solar cell: 1. printing glue first and then covering solder wire; and 2. covering solder wire first and then printing glue. These two printing methods have their own advantages and disadvantages. The first method can save silver paste consumption and effectively prevent the solder wire from moving during lamination, but the degree of wrapping of the solder wire is small, resulting in low tension. The second method does not need to consider the problem of calendering, but the consumption of silver paste is large, resulting in increased cost. SUMMARY

[0005] Therefore, it is necessary to provide a preparation method of a photovoltaic module to solve the above problems. A photovoltaic module is also provided.

[0006] The preparation method of the photovoltaic module comprises the following steps: applying glue to a plurality of glue application positions on the soldering surface of a solar cell, the glue application positions being arranged between fine grid lines arranged in a first direction, the distance between adjacent two fine grid lines being 1.05-1.13 mm, the thixotropic index Ti of the glue being 2.4-3.2, and the glue application width being 0.4-0.52 mm; stacking a solder strip on the soldering surface and on the glue, the length direction of the solder strip being along the first direction, the width direction of the solder strip being perpendicular to the first direction, the thickness direction of the solder strip being perpendicular to the solar cell, and the width of the solder strip being 0.2-0.26 mm; pressing the solder strip to each fine grid line by using a pressing tool; curing the glue; and soldering the solder strip to each fine grid line.

[0007] In some embodiments, the soldering surface is the back surface of the solar cell, or the soldering surface is the front surface and the back surface of the solar cell.

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

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

[0010] In some embodiments, the glue is applied to the glue application sites by inkjet, screen printing or dispensing.

[0011] In some embodiments, after the solder strip is pressed against the battery piece by the 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, pressing the solder strip against each of the fine grid lines by the pressing tool includes pressing the solder strip by pressing needles of the pressing tool to provide a pressing force that causes the solder strip to move toward the battery piece, wherein the pressing force provided by two pressing needles at the two ends in the first direction is less than the pressing force provided by the remaining pressing needles.

[0014] In some embodiments, the length of the two pressing needles at the two ends in the first direction is greater than the length of the remaining pressing needles; or the pressing needles are elastically connected to the pressing tool by elastic members, and the compression amount of the two elastic members at the two ends in the first direction is greater than the compression amount of the remaining elastic members.

[0015] A photovoltaic module prepared by the method.

[0016] In this application, for the distance between 1.05-1.13 mm of the two adjacent fine grid lines, the glue with a thixotropic index Ti of 2.4-3.2 is selected, the glue application width is controlled to be 0.4-0.52 mm, and the width of the solder strip used in combination is 0.2-0.26 mm. In this way, after the solder strip is pressed against each of the fine grid lines, the glue can flow without shielding the adjacent fine grid lines, thereby ensuring the power of the photovoltaic module. Moreover, the degree of wrapping the solder strip by the glue in the range of 40-80% can meet the demand of the glue on the tensile force of the solder strip, and the solder strip does not need to be completely wrapped by the glue, thereby reducing the amount of glue used. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 FIG. 1 is a schematic diagram of a glue application site on a main grid battery piece in a photovoltaic module according to an embodiment of the present application.

[0018] Figure 2Figure 1 is a schematic diagram of a glue application position on a main grid cell in a photovoltaic module according to an embodiment of the present application.

[0019] Figure 3 Figure 2 is a schematic diagram of a pressing tool according to an embodiment of the present application.

[0020] Figure 4 Figure 3 is a flow chart of a method for manufacturing a photovoltaic module according to an embodiment of the present application.

[0021] Figure 5 Figure 4 is an effect diagram of a cell before glue rolling in a photovoltaic module according to an embodiment of the present application.

[0022] Figure 6 Figure 5 is an effect diagram of a cell after glue rolling in a photovoltaic module according to an embodiment of the present application.

[0023] Figure 7 Figure 6 is a schematic diagram of a 40% solder wire wrapped by glue in a photovoltaic module according to an embodiment of the present application.

[0024] Figure 8 Figure 7 is a schematic diagram of a 60% solder wire wrapped by glue in a photovoltaic module according to an embodiment of the present application.

[0025] Figure 9 Figure 8 is a schematic diagram of a 80% solder wire wrapped by glue in a photovoltaic module according to an embodiment of the present application.

[0026] Figure 10 Figure 9 is a partial interface diagram of a photovoltaic module according to an embodiment of the present application, in which 60% solder wire is wrapped by glue.

[0027] Reference signs:

[0028] 10, cell; 110, soldering surface; 120, fine grid line; 130, glue application position; 140, glue; 150, solder strip; 160, main grid line; 20, pressing tool; 210, mounting seat; 220, pressing needle; 230, elastic member; 240, limiting structure. DETAILED DESCRIPTION

[0029] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a number of different ways beyond the specific embodiments described and it is therefore contemplated that the present application covers any and all modifications, equivalents and alternatives falling within the scope of the present application. It should also be noted that, in this disclosure, "comprising" means "including, but not limited to".

[0030] In the description of the application, it should be understood that, if there are these terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0031] In addition, if there are these terms "first", "second", these terms are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the application, if the term "multiple" appears, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise explicitly specified.

[0032] In this application, unless otherwise explicitly specified and limited, if there are terms "installation", "connection", "connection", "fixation" and the like, these terms should be broadly understood. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0033] In this application, unless otherwise explicitly specified and limited, if there are similar descriptions such as "on" or "under" the first feature on the second feature, the meaning can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" of the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" of the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0034] It is to be noted that when an element is referred to as being "on" or "connected to" another element, it can be directly on the other element or intervening elements can also be present. In addition, it is to be noted that when a member is referred to as being "connected", it is not limited to the cases where the member is directly connected to the other element or intervening elements can also be present. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions as used herein are for the purpose of illustration only and are not intended to be limiting.

[0035] As described above, when the welding strip needs to be directly connected to the fine grid lines (also referred to as secondary grid lines) on the battery piece, if the method of printing glue first and then covering the welding wire is adopted, the amount of glue can be saved and the welding wire can be effectively prevented from moving during the lamination process; however, the degree of wrapping of the welding wire is small, resulting in low tension. If the amount of glue is increased to ensure the tension, after the glue is covered and calendered, the degree of wrapping of the welding wire increases, but the glue is easily blocked from the adjacent fine grid lines after being calendered.

[0036] In view of the above contradiction, the present application provides a preparation method of a photovoltaic module, which can save the amount of glue and avoid the glue being easily blocked from the adjacent fine grid lines after being calendered. In order to facilitate the understanding of the present application, first, the architecture of the photovoltaic module involved in the present application is described.

[0037] Reference Figure 1 The photovoltaic module involved in the present application includes at least one battery string. The battery string includes at least one battery piece 10. Among them, Figure 1 Only one battery piece 10 is schematically shown in the figure. A plurality of fine grid lines 120 are arranged along a first direction X on the welding surface 110 of each battery piece 10. The gap between adjacent fine grid lines 120 is a glue applying position 130 for applying glue 140.

[0038] Optionally, as shown in Figure 1 The battery piece 10 in the present application can be a main grid-free battery piece; at this time, the glue is applied between the adjacent fine grid lines 120.

[0039] Optionally, as shown in Figure 2 The battery piece 10 is spaced apart from a plurality of main grid lines 160 arranged at intervals along a second direction Y. The length direction of the main grid line 160 is perpendicular to the fine grid line 120. At this time, the position of the glue is avoided when the glue is applied. For example, as shown in Figure 2 The battery piece 10 is provided with two main grid lines 160 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 battery pieces 10 in the battery string can be the same as or perpendicular to the first direction X. The present embodiment does not limit the structure of the battery piece, and the types of the battery piece include, but are not limited to, a passivated emitter rear cell (PERC), a tunnel oxide passivated contact (TOPCon), a heterojunction with intrinsic thin-film (HJT), an interdigitated back contact (IBC), a perovskite cell, and the like.

[0041] With reference to Figure 3 The preparation method of the photovoltaic module provided in the present application comprises the following steps:

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

[0043] In this step, glue 140 is applied to each of the plurality of glue applying positions 130 on the welding surface 110 of each battery piece 10. That is, glue is applied between the adjacent fine grid lines 120. When glue is applied between the adjacent two fine grid lines 120, it is preferred to apply glue to the middle position.

[0044] The thixotropic index Ti of the glue 140 reflects the stability and fluidity of the glue 140 under stress. The greater the thixotropic index, the smaller the degree of destruction of the structure of the glue 140 after stress, and the higher the stability and fluidity. The smaller the thixotropic index, the easier the structure is to be destroyed after stress, and the poorer the stability and fluidity.

[0045] The glue 140 has light transmittance. Optionally, the light transmittance of the glue 140 is greater than or equal to 85%, which can reduce the light loss caused by the reflection of incident light on the surface of the battery piece, and also can ensure that more incident light is reflected to the surface of the battery piece for power generation, so as to effectively improve the power of the photovoltaic module.

[0046] The glue width refers to the width of the glue 140 between the 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, a plurality of rows and columns of glue areas are formed. In each row, the number of glue areas is at least one. Alternatively, in each row, the glue position 130 between any two adjacent fine grid lines 120 is glued to form a continuous arrangement of glue areas. Alternatively, in each row, the glue is applied to the adjacent two fine grid lines 120 at intervals to form discontinuous glue areas to save some glue 140. Similarly, in each column, the number of glue positions 130 is also at least one, and the formed glue areas are continuously arranged or arranged at intervals.

[0047] S200, the solder strip 150 is stacked on the welding surface 110 and located on the glue 140, the length direction of the solder strip 150 is along the first direction X, the width direction of the solder strip 150 is perpendicular to the first direction X, the thickness direction of the solder strip 150 is perpendicular to the battery piece, and the width of the solder strip 150 is 0.2-0.26mm.

[0048] In this application, the length direction of the solder strip 150 is along the first direction X. The width direction of the solder strip 150 is consistent with the length direction of the fine grid line 120, both along the second direction Y. It is easy to understand that the second direction Y is perpendicular to the first direction X. In this application, along the second direction Y perpendicular to the first direction X, that is, the length direction of the fine grid line 120, the solder strip 150 can be provided with a plurality of.

[0049] The cross section of the solder strip 150 can be circular, semicircular, oval, rectangular or triangular. This application does not limit it. When the cross section of the solder strip 150 is circular, the width of the solder strip 150 is the diameter of the solder strip 150.

[0050] S300, the solder strip 150 is pressed to each fine grid line 120 by the pressing tool 20.

[0051] In this step, referring to Figure 1 、 Figure 4 , the solder strip 150 is pressed to each fine grid line 120 by the pressing tool 20. In this way, it can be ensured that the solder strip 150 is tightly attached to the fine grid line 120 on the corresponding battery piece 10, so as to ensure that after welding, the solder strip 150 and the fine grid line 120 form a high-quality alloying connection, preventing false welding.

[0052] Alternatively, the pressing tool 20 includes a mounting seat 210 and a plurality of pressing needles 220 arranged on the mounting seat 210. The plurality of pressing needles 220 are arranged at intervals along the first direction X, and each pressing needle 220 corresponds to a fine grid line 120.

[0053] Further, the pressing tool 20 is provided with a plurality of rows of pressing needles 220 in the second direction Y, and the pressing needles 220 in each row are arranged at intervals in the first direction X, and each pressing needle 220 corresponds to a fine grid line 120. Thus, multiple positions of the fine grid line on the welding surface 110 can be pressed at the same time.

[0054] As shown in Figure 5 and Figure 6 , wherein Figure 5 is an effect diagram before the glue is rolled. Figure 6 is an effect diagram after the glue is rolled, and the solder strip is removed to show the effect after the glue is rolled. Figure 5 and Figure 6 , the two white lines parallel to each other are fine grid lines, and the two fine grid lines are arranged in the up-down direction (i.e., the first direction X); the glue is between the two fine grid lines. As can be seen, after the glue is rolled, the width of the glue increases in the up-down direction, but the glue is still between the two fine grid lines and does not block the fine grid lines.

[0055] S400, curing the glue 140. After curing, the solder strip 150 is fixed to the welding surface 110 of the battery piece 10 through the cured glue 140. The glue 140 can be a heat-curing glue or a light-curing glue. The curing method can be heat curing or light irradiation curing.

[0056] S500, welding the solder strip 150 to each of the fine grid lines 120. A laser welding device can be used for welding, and each solder strip 150 is welded to the fine grid line 120.

[0057] In this application, for the interval of 1.05mm-1.13mm between two adjacent fine grid lines 120, the glue 140 with a thixotropic index Ti of 2.4-3.2 is selected, and the glue application width is controlled to be between 0.4mm-0.52mm, and the width of the solder strip 150 used in cooperation is 0.2mm-0.26mm. In this way, after the solder strip 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 wrapping of the glue 140 on the solder strip 150 is within the range of 40%-80%, which can meet the tensile force requirement of the glue 140 on the solder strip 150, and the solder strip 150 does not need to be completely wrapped by the glue 140, thereby reducing the amount of glue 140 used.

[0058] Further, the method for preparing the photovoltaic module further comprises the steps of arranging a first glue film and a front plate, a second glue film and a back plate on both sides of the battery piece respectively, and laminating, thereby forming a photovoltaic module comprising a front and back protective structure. For example, the second glue film is laid on the back plate. Then the battery piece is laid on the second glue film. Then the first glue film is laid on the battery piece, and the front plate is laminated to the first glue film. Finally, the first glue film and the front plate, the second glue film and the back plate are laminated.

[0059] In some embodiments, the welding surface 110 is the back surface of the battery piece 10, or the welding surface 110 is the front surface and the back surface of the battery piece 10. According to the arrangement of the welding surface, the battery piece is divided into two types, wherein: the first type of battery piece, the fine grid lines are arranged on both surfaces, that is, both surfaces are welding surfaces; the second type of battery piece, only one surface is provided with fine grid lines, that is, only one surface is a welding surface.

[0060] In some embodiments, the distance between the two adjacent fine grid lines is 1.13 mm, the thixotropic index Ti of the glue is 2.4, the glue application width is 400-430 μm, and the width of the solder 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 glue application amount of the two glue application positions 130 at both ends of the battery piece 10 is greater than that of the remaining glue application positions 130.

[0062] In order to avoid the first and last virtual welding, in the present application, in the first direction X, the glue application amount of the first and last two glue application positions 130 is large, so that after the solder strip is pressed by the pressing tool 20, the solder strip 150 is combined with the battery piece 10 at the first and last two glue application positions 130 more tightly, and the solder strip 150 can be closely attached to the first and last two fine grid lines 120, thereby effectively avoiding the first and last virtual welding of the solder strip during welding.

[0063] In some embodiments, the glue is applied to the glue application position 130 by inkjet, silk screen or dispensing. The specific process of glue application is not limited, as long as the glue of the above width range can be applied.

[0064] Optionally, the glue can be applied to the back or front surface of the battery piece 10 by inkjet, silk screen or dispensing using a glue application mechanism.

[0065] In some embodiments, after the solder strip 150 is pressed against the battery piece by the pressing tool 20, the width of the glue is less than 0.7 mm.

[0066] In the present application, by controlling the glue application amount, the width of the glue is further made to be less than 0.7 mm after the solder strip is pressed against the battery piece 10. In this way, on the one hand, the tensile force of the glue 140 on the solder strip 150 is good, and on the other hand, the blocking degree of the glue 140 on the surface of the battery piece is low, thereby ensuring the power of the photovoltaic module.

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

[0068] In the present application, after the glue 140 is selected, 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 the solder strip 100%.

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

[0070] Further, please refer to Figure 10 , Figure 10 , which shows a partial cross-sectional view of a photovoltaic module, in which 60% of the solder strip is wrapped by the glue 140. Figure 10 In the figure, the number 1 represents the object, i.e. the glue, the cylindrical object above the glue is the solder strip, and the object above the solder strip is the encapsulating film in the photovoltaic module.

[0071] Through the tensile test verification, when 40-80% of the solder strip 150 is wrapped by the glue 140, the fixed tensile force requirement of the solder strip 150 in the photovoltaic module of the present application can be met. Thus, the amount of glue 140 can be saved, and the cost can be reduced.

[0072] In some embodiments, step S300 uses the pressing tool 20 to press the solder strip 150 against each of the fine grid lines 120, which includes:

[0073] S310, using the pressing needles 220 of the pressing tool 20 to press the solder strip 150 to provide a pressing force for the solder strip 150 towards the cell sheet 10, wherein the pressing force provided by the two pressing needles 220 at the two ends in the first direction X is less than the pressing force provided by the remaining pressing needles 220.

[0074] In the present embodiment, by providing a pressing force for the solder strip 150 with the pressing tool 20, the two pressing needles 220 at the two ends can provide a greater pressing force for the solder strip 150, which can ensure that the end portion of the solder strip 150 is pressed down, avoiding the end portion of the solder strip 150 from being warped due to a greater amount of glue or other reasons, and then avoiding the solder strip 150 in the warped state from being deformed and displaced or damaged by the pressing.

[0075] In some embodiments, the length of the two pressing needles 220 at the two ends in the first direction X is greater than the length of the remaining pressing needles 220.

[0076] In the embodiment, the lengths of the two end pressure pins 220 are set to be greater than the length of the pressure pin 220. In this way, when the welding strip 150 is pressed by the pressing tool 20, the two end pressure pins 220 can provide more pressure to the welding strip 150 under the same stroke, so as to ensure that the end of the welding strip 150 is pressed down and the end of the welding strip 150 is prevented from being warped.

[0077] In some embodiments, with reference to Figure 4 , the pressure pin 220 is elastically connected to the pressing tool 20 by the elastic member 230, and the compression amount of the two end elastic members 230 in the first direction is greater than the compression amount of the other elastic members 230.

[0078] Optionally, the elastic member 230 is a spring, and the force applied by the pressure pin to the welding strip 150 is adjusted by adjusting the compression amount of the spring. The elastic force of the two end springs is set to be greater than the elastic force of the other springs, so that the pressure of the two end pressure pins 220 in the first direction X is greater than the pressure of the other pressure pins 220, which can ensure that the end of the welding strip 150 is pressed down and the end of the welding strip 150 is prevented from being warped.

[0079] Optionally, the pressing tool 20 includes a mounting seat 210, a pressure pin 220, an elastic member 230, and a limiting structure 240. The pressure pin 220 is movably mounted in the mounting hole (not shown) of the mounting seat 210. The limiting structure 240 is arranged above the mounting seat 210 and cooperates with the pressure pin 220 to prevent the pressure pin 220 from being pulled out. The elastic member 230 is sleeved on the pressure pin 220, and the two ends of the elastic member 230 abut against the mounting seat 210 and the pressure pin 220 respectively, so as to achieve the movable mounting of the pressure pin 220. At this time, the pressure of the pressure pin can be changed by adjusting the compression amount of the elastic member 230.

[0080] The advantages of the preparation method of the photovoltaic module in the embodiments of the present application will be further illustrated by Examples 1-12. The statistical results of Examples 1-12 are shown in Table 1.

[0081] Table 1

[0082] Specifically, in Examples 1-12, the sizing object of Examples 1-6 is the busbar-free cell shown in the architecture of Figure 1 , and the sizing object of Examples 7-12 is the cell with partial busbar shown in the architecture of Figure 2 . Each example is tested at least once, and the sizing width is controlled within the sizing width range of the example. That is, when each example is tested, the spacing between the two adjacent fine grid lines, the thixotropic index Ti of the glue, and the width of the welding strip are determined, and the sizing width is allowed to fluctuate within a certain range, so that the process difficulty is not great and is easy to operate.

[0083] For example, for the embodiment 1, the pitch 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 application width is 450-470 μm, and for example, the glue application width can be 450 μm, 455 μm, 460 μm, or 470 μm in the 4 tests. In the 4 tests, the glue width after calendering is 0.57 mm, 0.58 mm, 0.59 mm, and 0.61 mm, respectively. The other embodiments are similar to the operation mode.

[0084] From the statistical results in Table 1, in each embodiment, the width of the glue 140 after calendering is less than the pitch between the adjacent fine grid lines, and the fine grid lines 120 are not covered. In addition, the tensile test meets the verification that the glue meets the tensile requirement of the solder strip, and the tensile force is not less than 0.1 N.

[0085] Therefore, by using the preparation method of the present application, when the glue is applied between the fine grid lines with a certain pitch range, by selecting a glue with a suitable thixotropic index and controlling the glue application amount, and by using a solder strip with a suitable size to cover the glue and being pressed, the glue after calendering will not cover the fine grid lines, so that the degree of the glue wrapping the solder strip is in the range of 40%-80%, which can meet the tensile requirement of the glue to the solder strip, and the glue does not need to wrap the solder strip completely, thereby reducing the amount of glue.

[0086] The present application also provides a photovoltaic module prepared by any one of the above methods. The photovoltaic module of the present application has a small amount of glue and sufficient tensile force to the solder strip, and the glue will not block the fine grid lines.

[0087] The technical features of the above embodiments can be combined in any way. In order to make the description simple, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist, they should be considered as the scope of the present application.

[0088] The above embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for preparing a photovoltaic module, characterized in that, include: Adhesive is applied to multiple application points on the welding surface of the battery cell. The application points are located between 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 adhesive is 2.4-3.

2. The application width is 0.4mm-0.52mm. The solder strip is stacked on the welding surface and located on the adhesive. The length direction of the solder strip is along the first direction, the width direction of the solder strip is perpendicular to the first direction, the thickness direction of the solder strip is perpendicular to the battery cell, and the width of the solder strip is 0.2mm-0.26mm. The welding strip is pressed onto each of the fine grid lines using a clamping fixture; The adhesive is cured; The solder strips are soldered to each of the fine 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 both the front and back sides of the battery cell.

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

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

5. The method according to claim 1, characterized in that, The adhesive is applied to the application area using inkjet printing, screen printing, or dispensing methods.

6. The method according to claim 1, characterized in that, After the welding strip is pressed onto the battery cell using a clamping fixture, the width of the adhesive 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 adhesive is lower than the top surface of the solder strip, and 40%-80% of the solder strip is covered by the adhesive.

8. The method according to claim 1, characterized in that, The process of pressing the solder strip onto each of the fine grid lines using a clamping fixture includes: The welding strip is pressed with the pressure pins of the clamping fixture to provide pressure that orients the welding strip toward the battery cell, wherein the pressure provided by the two pressure pins at both ends in a first direction is less than the pressure provided by the remaining pressure pins.

9. The method according to claim 8, characterized in that, The length of the two pressure pins at both ends in the first direction is greater than the length of the remaining pressure pins; or the pressure pins are elastically connected to the clamping fixture by elastic elements, and the compression amount of the two elastic elements at both ends in the first direction is greater than the compression amount of the remaining elastic elements.

10. A photovoltaic module, characterized in that, Prepared by the method described in any one of claims 1-9.

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