Preparation method of photovoltaic module and photovoltaic module

Abstract

The invention discloses a preparation method of a photovoltaic module and the photovoltaic module. The preparation method comprises the following steps: coating glue points on the surface of a welding wire; the welding wire is transferred to the surface of the battery piece; curing the glue points to enable the glue points to cover the welding wire and the battery piece; laminating the front cover plate, the front adhesive film, the battery piece, the back adhesive film and the back cover plate to form a laminated assembly; laminating the laminated assembly to form a laminated assembly; wherein the viscosity of the glue point is eta, and eta is more than or equal to 6000 mPa.s and less than or equal to 10000 mPa.s. According to the method, the glue point can be stably attached to the welding wire and gradually flows to the battery piece from the outer surface of the welding wire at the initial stage of curing, so that the welding wire and the battery piece are jointly covered, and the glue point is fixedly connected with the battery piece after being cured; the possibility that the glue points overflow to the connecting position of the welding wire and the grid line of the battery piece in the subsequent stacking and / or laminating process is avoided, so that the possibility of pseudo soldering is reduced, and the production yield of the photovoltaic module is improved.

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] Currently, the process of connecting welding wire to solar cells typically involves applying glue first and then laying the welding wire. This secures the connection between the welding wire and the solar cell with glue, allowing for alloying between the welding wire and the solar cell during subsequent PV module lamination. However, during PV module lamination, the size and height of the glue dots formed during glue application are difficult to control. This can lead to the risk of glue dots flowing to the connection between the welding wire and the solar cell grid lines during subsequent lamination, resulting in a risk of cold solder joints. This can seriously affect the yield of PV modules. Summary of the Invention

[0003] In view of this, the present application provides a method for preparing a photovoltaic module and a photovoltaic module to solve the technical problem in the prior art that glue spots easily flow to the connection between the welding wire and the battery cell grid line during lamination, resulting in cold solder joints.

[0004] The present application provides a method for preparing a photovoltaic module, which includes: applying glue dots on the surface of a welding wire; transferring the welding wire to the surface of a battery cell; curing the glue dots so that the glue dots cover the welding wire and the battery cell; stacking a front cover plate, a front adhesive film, a battery cell, a back adhesive film, and a back cover plate to form a stacked assembly; laminating the stacked assembly to form a laminated assembly; wherein the viscosity of the glue dots is η, and η satisfies 6000mPa·s≤η≤10000mPa·s.

[0005] In the embodiment of the present application, such a design method can make the glue point stably adhere to the welding wire, and gradually flow from the outer surface of the welding wire to the battery cell in the early stage of solidification to achieve common coverage of the welding wire and the battery cell, and achieve a fixed connection between the two after the glue point is completely solidified, avoiding the possibility of the glue point overflowing to the connection between the welding wire and the battery cell grid line during the subsequent stacking and / or lamination process, thereby reducing the possibility of cold welding, which is beneficial to improving the production yield of photovoltaic modules.

[0006] When the viscosity of the glue dot satisfies 6000mPa·s≤η≤10000mPa·s, the adhesiveness and fluidity of the glue dot are moderate, so that it can be stably attached to the upper surface of the welding wire before completing the curing process, so as to ensure a good bonding effect between the glue dot and the welding wire, thereby achieving a fixed connection between the welding wire and the battery cell while reducing the possibility of cold welding, improving the production yield of photovoltaic modules and extending their service life.

[0007] In one possible embodiment, the welding wire includes a first welding wire, and the glue dots are coated on the surface of the first welding wire through a glue outlet. When the glue dots are coated on the surface of the first welding wire, the preparation method further includes: detecting the width L1 of the first welding wire, and L1 satisfies 1mm≤L1≤1.5mm; moving the projection center of the glue outlet along the first direction x and the second direction y to align with the long side edge of one side of the first welding wire along the third direction z, and coating the glue dots; moving the projection center of the glue outlet along the first direction x and the second direction y to align with the long side edge of the other side of the first welding wire along the third direction z, and coating the glue dots; repeating the above steps so that the glue dots are spaced apart along the second direction y, and alternately cover the long side edges on both sides of the first welding wire along the first direction x.

[0008] In one possible embodiment, the welding wire includes a second welding wire, and the glue dots are coated on the surface of the second welding wire through the glue outlet. When the glue dots are coated on the surface of the second welding wire, the preparation method further includes: detecting the width L2 of the second welding wire, and L2 satisfies 0.2mm≤L2≤0.3mm; moving the projection center of the glue outlet along the first direction x and the second direction y to be aligned with the axis of the second welding wire along the third direction z, and coating the glue dots; repeating the above steps so that the glue dots are spaced apart and covered on the upper surface of the second welding wire along the second direction y, and the projections of adjacent glue dots along the second direction y overlap.

[0009] In one possible embodiment, during the process of curing the glue spots so that the glue spots cover the welding wires and battery cells, the preparation method further includes: thermally curing the glue spots, where the thermal curing temperature is T, and T satisfies 130°C≤T≤300°C.

[0010] The present application also provides a photovoltaic module, which is made using any of the preparation methods described above. The photovoltaic module includes a battery cell, a welding wire and glue dots. The welding wire is placed on the surface of the battery cell, and the glue dots cover the welding wire and the battery cell.

[0011] The glue spots are spaced apart along the second direction y and alternately cover the long edges on both sides of the welding wire along the first direction x, or the glue spots are spaced apart along the second direction y and cover the upper surface of the welding wire, and the projections of adjacent glue spots along the second direction y overlap.

[0012] In an embodiment of the present application, when the glue points are spaced apart along the second direction y and alternately cover the long side edges on both sides of the first welding wire along the first direction x, such a design method can not only improve the stability and reliability of the connection between the first welding wire and the battery cell, but also reduce the amount of glue used, thereby reducing the production cost of the photovoltaic module.

[0013] At the same time, the effective contact area between the first welding wire and the grid line of the battery cell can be increased, so that the two can be directly alloyed and connected better, which is beneficial to improving the current transmission efficiency and the photoelectric conversion efficiency of the photovoltaic module.

[0014] In addition, the glue points alternately distributed along the first direction x can also improve the uniformity of the force on the first welding wire to avoid stress concentration, thereby reducing the risk of the first welding wire tilting, offset or warping during subsequent stacking and / or lamination, which is beneficial to improving the production yield of photovoltaic modules.

[0015] When the glue points are spaced apart and covered on the upper surface of the second welding wire along the second direction y, and the projections of adjacent glue points along the second direction y overlap, such a design method can enable multiple spaced glue points to form a continuous bonding line in the second direction y, so as to improve the stability and reliability of the connection between the second welding wire and the battery cell, thereby enabling the photovoltaic module to have strong mechanical reliability in harsh environments, so as to resist mechanical loads and vibrations, and help extend the service life of the photovoltaic module.

[0016] In one possible embodiment, the welding wire includes a first welding wire, and along the second direction y, the distance between adjacent glue points is L3, and L3 satisfies 12mm≤L3≤30mm, and along the first direction x, the distance between adjacent glue points is L5, and L5 satisfies 0.5mm≤L5≤1mm.

[0017] In a possible implementation, the welding wire includes a second welding wire, and along the second direction y, the distance between adjacent glue points is L4, and L4 satisfies 10 mm ≤ L4 ≤ 20 mm.

[0018] In a possible embodiment, a receiving groove and a guide groove are provided on the surface of the welding wire. The receiving grooves are spaced apart along the second direction y, and the guide grooves are located on at least one side of the receiving groove along the first direction x and are connected to the side wall of the receiving groove.

[0019] In a possible embodiment, along the third direction z, the guide groove is inclined relative to the receiving groove toward the direction close to the battery cell, and an angle α is formed between the bottom wall of the guide groove and the bottom wall of the receiving groove, and α satisfies 5°≤α≤30°.

[0020] In a possible implementation, the material of the glue point is epoxy resin or polyurethane, the thixotropic index of the glue point is TI, and TI satisfies TI>4.

[0021] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 This is a schematic structural diagram of the photovoltaic module provided in this application in a first embodiment;

[0024] Figure 2 yes Figure 1 sectional view of

[0025] Figure 3 is a schematic structural diagram of the photovoltaic assembly provided in this application in a second embodiment;

[0026] Figure 4 yes Figure 3 sectional view of .

[0027] Description of reference numerals:

[0028] 1-battery cell;

[0029] 2- welding wire;

[0030] 21-first welding wire;

[0031] 22- second welding wire;

[0032] 23-accommodation slot;

[0033] 24-guide groove;

[0034] 3-Glue dots.

[0035] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION

[0036] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0037] It should be clear that the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0038] The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used in the description of the embodiments of the present application and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0039] It should be understood that the term "and / or" used herein only describes an association relationship of associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0040] Embodiments of the present application provide a preparation method of a photovoltaic module, as shown in Figure 1 and Figure 3 The preparation method comprises: coating a glue point 3 on the surface of a welding wire 2; transferring the welding wire 2 to the surface of a cell piece 1; curing the glue point 3 to cover the welding wire 2 and the cell piece 1; stacking a front cover plate (not marked in the figure), a front adhesive film (not marked in the figure), the cell piece 1, a back adhesive film (not marked in the figure) and a back cover plate (not marked in the figure) to form a stacked assembly; laminating the stacked assembly to form a laminated assembly; wherein the viscosity of the glue point 3 is η, and η satisfies 6000 mPa·s≤η≤10000 mPa·s.

[0041] In the embodiments of the present application, by first coating the glue point 3 on the surface of the welding wire 2, and then curing the glue point 3 on the welding wire 2 after transferring the welding wire 2 carrying the glue point 3 to the surface of the cell piece 1, the glue point 3 can be stably attached to the upper surface of the welding wire 2 (i.e. the surface of the welding wire 2 away from the cell piece 1), and can gradually flow along the outer surface of the welding wire 2 to the cell piece 1 in the initial curing stage, to realize the common coverage of the welding wire 2 and the cell piece 1 by the glue point 3. After the glue point 3 is cured, the fixed connection between the welding wire 2 and the cell piece 1 can be realized, to improve the stability and reliability of the connection between the two, reduce the possibility of relative movement between the welding wire 2 and the cell piece 1 in the subsequent stacking and / or lamination process, reduce the possibility of glue point 3 overflowing to the connection between the welding wire 2 and the cell piece 1 grid line, thereby avoiding the risk of false welding, and further facilitating the improvement of the production yield of the photovoltaic module.

[0042] The glue point 3 gradually flows from the upper surface of the welding wire 2 along the outer surface of the welding wire 2 to the battery piece 1, which can avoid the risk of poor connection between the welding wire 2 and the battery piece 1 due to uneven distribution of the amount and position of the glue of the glue point 3 in the prior art (i.e., the glue point 3 is located between the welding wire 2 and the battery piece 1), thereby affecting the performance and quality of the photovoltaic module. Therefore, such a design not only ensures the stability and reliability of the connection between the two, but also increases the effective contact area between the welding wire 2 and the battery piece 1, so that the welding wire 2 and the grid line on the surface of the battery piece 1 can be directly alloyed and connected to form a low-resistance current channel, thereby improving the current transmission efficiency and increasing the output power of the photovoltaic module.

[0043] At the same time, during the assembly of the welding wire 2 and the battery piece 1, the glue point 3 is coated on the upper surface of the welding wire 2, so that the operator can more intuitively observe the proportion (such as width proportion or thickness proportion) of the glue point 3 and the welding wire 2, so that the operator can preliminarily judge the amount of glue of the glue point 3 and fill or remove it, thereby avoiding the risk of poor connection between the two due to too little glue of the glue point 3, and easy relative displacement, and also avoiding the risk of too much glue of the glue point 3 penetrating into the connection between the welding wire 2 and the grid line during subsequent lamination and / or lamination, causing virtual welding. Therefore, such a design can improve the production yield of the photovoltaic module, thereby facilitating the stability and reliability of the photovoltaic module during operation and prolonging its service life.

[0044] In addition, the viscosity of the glue point 3 is η, and η can be 6000 mPa·s, 6100 mPa·s, 6200 mPa·s, 6300 mPa·s, 6400 mPa·s, 6500 mPa·s, 6600 mPa·s, 6700 mPa·s, 6800 mPa·s, 6900 mPa·s, 7000 mPa·s, 7100 mPa·s, 7200 mPa·s, 7300 mPa·s, 7400 mPa·s, 7500 mPa·s, 7600 mPa·s, 7700 mPa·s, 7800 mPa·s, 7900 mPa·s, 8000 mPa·s, 8100 mPa·s, 8200 mPa·s, 8300 mPa·s, 8400 mPa·s, 8500 mPa·s, 8600 mPa·s, 8700 mPa·s, 8800 mPa·s, 8900 mPa·s, 9000 mPa·s, 9100 mPa·s, 9200 mPa·s, 9300 mPa·s, 9400 mPa·s, 9500 mPa·s, 9600 mPa·s, 9700 mPa·s, 9800 mPa·s, 9900 mPa·s, 10000 mPa·s, etc.

[0045] When the viscosity of the glue point 3 is too small (for example, η is less than 6000 mPa·s), the adhesion of the glue point 3 is too low and the fluidity is too high, so that the glue point 3 cannot be stably attached to the surface of the solder wire 2 in the initial state, and the glue point 3 is prone to flow or drop before the solder wire 2 is transported to the battery piece 1, resulting in insufficient glue amount of the glue point 3, thereby affecting the connection effect between the solder wire 2 and the battery piece 1, and in the subsequent lamination and / or lamination process, the glue point 3 is prone to excessive flow, which may overflow to the connection between the solder wire 2 and the main grid, resulting in a high possibility of false welding, thereby affecting the working performance and service life of the photovoltaic module.

[0046] When the viscosity of the glue point 3 is too large (for example, η is greater than 10000 mPa·s), the adhesion of the glue point 3 is too high and the fluidity is too low, so that the glue point 3 cannot flow smoothly along the outer surface of the solder wire 2 to the battery piece 1 in the molten state, thereby easily causing the glue point 3 to cover the solder wire 2 and the battery piece 1 insufficiently or unevenly, resulting in ineffective connection between the solder wire 2 and the battery piece 1, thereby affecting the production yield of the photovoltaic module.

[0047] Therefore, when the viscosity of the glue point 3 satisfies 6000 mPa·s≤η≤10000 mPa·s, the adhesion and fluidity of the glue point 3 are moderate, so that the glue point 3 can be stably attached to the upper surface of the solder wire 2 before completing the solidification treatment, so as to ensure that the glue point 3 and the solder wire 2 have good adhesion effect, thereby being capable of realizing fixed connection between the solder wire 2 and the battery piece 1 while reducing the possibility of false welding, improving the production yield of the photovoltaic module, and prolonging the service life thereof.

[0048] In a possible implementation, the surface of the battery piece 1 can be provided with a first preset position (not marked in the figure) for placing the solder wire 2, and the surface of the solder wire 2 can be provided with a second preset position (not marked in the figure) for placing the glue point 3, so as to improve the positioning accuracy of the solder wire 2 and the glue point 3, thereby improving the transportation efficiency of the solder wire 2 and the coating efficiency of the glue point 3.

[0049] It should be noted that in the present embodiment, the length direction of the photovoltaic module is defined as the first direction x, the width direction of the photovoltaic module is defined as the second direction y, and the thickness direction of the photovoltaic module is defined as the third direction z.

[0050] In the present embodiment, the solder wire 2 is located on one side of the battery piece 1 along the third direction z, the glue point 3 is located on the side of the solder wire 2 away from the battery piece 1 along the third direction z, and a plurality of solder wires 2 are distributed at intervals along the first direction x and extend along the second direction y.

[0051] In a specific implementation, as shown in FIG. 1, the photovoltaic module 100 includes a plurality of battery pieces 1 and a plurality of solder wires 2. Figure 1As shown, the welding wire 2 includes a first welding wire 21, and the glue dots 3 can be coated on the surface of the first welding wire 21 through the glue outlet. When the glue dots 3 are coated on the surface of the first welding wire 21, the preparation method further includes: detecting the width L1 of the first welding wire 21, and L1 satisfies 1mm≤L1≤1.5mm; moving the projection center of the glue outlet along the first direction x and the second direction y to align with the long side edge of one side of the first welding wire 21 along the third direction z, and coating the glue dots 3; moving the projection center of the glue outlet along the first direction x and the second direction y to align with the long side edge of the other side of the first welding wire 21 along the third direction z, and coating the glue dots 3; repeating the above steps so that the glue dots 3 are spaced apart along the second direction y, and alternately cover the long side edges on both sides of the first welding wire 21 along the first direction x.

[0052] In the embodiment of the present application, by detecting the width of the welding wire 2, the operator can use different gluing methods to apply the glue, so as to achieve a more stable connection between the welding wire 2 and the battery cell 1.

[0053] When the width of the first welding wire 21 satisfies 1mm≤L1≤1.5mm, the width of the first welding wire 21 is relatively large, and the first welding wire 21 can be fixedly connected to the cell 1 by applying glue dots 3 to the long edges on both sides of the first welding wire 21. This helps ensure the connection between the first welding wire 21 and the cell 1 while controlling the amount of glue in a single glue dot 3 to be small, thereby improving the stability and reliability of the photovoltaic module during operation, increasing the production yield of the photovoltaic module, and extending its service life. In addition, compared to the prior art method of simultaneously covering the upper surface of the first welding wire 21 and the cell 1 along the first direction x with glue dots 3, the glue application method in this embodiment is safer and requires less total glue. This helps reduce the production cost of the photovoltaic module while reducing the risk of glue dots 3 penetrating into the connection between the first welding wire 21 and the grid line during subsequent stacking and / or lamination, resulting in a cold weld.

[0054] Among them, the width of the first welding wire 21 is L1, and L1 can specifically be 1mm, 1.02mm, 1.04mm, 1.06mm, 1.08mm, 1.1mm, 1.12mm, 1.14mm, 1.16mm, 1.18mm, 1.2mm, 1.22mm, 1.24mm, 1.26mm, 1.28mm, 1.3mm, 1.32mm, 1.34mm, 1.36mm, 1.38mm, 1.4mm, 1.42mm, 1.44mm, 1.46mm, 1.48mm, 1.5mm, etc.

[0055] At the same time, by arranging the glue points 3 to be distributed at intervals along the second direction y, and alternately covering the long side edges on both sides of the first welding wire 21 along the first direction x, it is beneficial to improve the uniformity of the force on the first welding wire 21. It can not only avoid the risk of the first welding wire 21 tilting, offset or warping along the first direction x due to uneven force on both sides, but also avoid stress concentration, which is beneficial to improve the stability and reliability of the connection between the first welding wire 21 and the battery cell 1.

[0056] In one possible embodiment, during the process of applying glue to the first welding wire 21, the glue outlet can be first controlled to move along the first direction x and the second direction y so that the projection center of the glue outlet is aligned with the long edge on the left side of the first welding wire 21 along the third direction z, and the glue outlet is controlled to move along the third direction z toward the direction close to the long edge so as to apply glue thereto for the first time. After the first application of glue is completed, the glue outlet is controlled to move along the third direction z toward the direction away from the long edge. Then, the glue outlet can be controlled to move along the first direction x and the second direction y so that the projection center of the glue outlet is aligned with the long edge on the right side of the first welding wire 21 along the third direction z, and the glue outlet is controlled to move along the third direction z toward the direction close to the long edge so as to apply glue thereto for the second time. After the second application of glue is completed, the glue outlet is controlled to move along the third direction z toward the direction away from the long edge. Then, the above steps are repeated so that the glue dots 3 are alternately distributed along the first direction x on the left and right long edges of the first welding wire 21, and the glue dots 3 on the left and right long edges are spaced apart along the second direction y. The preset distance that the glue outlet moves along the first direction x can be equal to the width of the first welding wire 21.

[0057] In a specific embodiment, Figure 3 As shown, the welding wire 2 includes a second welding wire 22, and the glue dots 3 are coated on the surface of the second welding wire 22 through the glue outlet. When the glue dots 3 are coated on the surface of the second welding wire 22, the preparation method further includes: detecting the width L2 of the second welding wire 22, and L2 satisfies 0.2mm≤L2≤0.3mm; moving the projection center of the glue outlet along the first direction x and the second direction y to be aligned with the axis of the second welding wire 22 along the third direction z, and coating the glue dots 3; repeating the above steps so that the glue dots 3 are spaced apart and covered on the upper surface of the second welding wire 22 along the second direction y, and the projections of adjacent glue dots 3 along the second direction y overlap.

[0058] In the embodiment of the present application, when the width of the second welding wire 22 satisfies 0.2mm≤L2≤0.3mm, the width of the second welding wire 22 is relatively small, so that the glue spot 3 can cover the surface of the second welding wire 22 and the battery cell 1 along the first direction x, so that the glue spot 3 can be directly applied on the second welding wire 22. A fixed connection between the second welding wire 22 and the battery cell 1 can be achieved, which is beneficial for improving the glue coating efficiency while ensuring a good connection effect between the second welding wire 22 and the battery cell 1, thereby improving the production yield of the photovoltaic module while improving the production efficiency of the photovoltaic module.

[0059] Among them, the width of the second welding wire 22 is L2, and L2 can specifically be 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, etc.

[0060] At the same time, by arranging the glue points 3 to be distributed at intervals along the second direction y and projecting them to overlap along the first direction x, it is beneficial to improve the uniformity of the force applied to the second welding wire 22 while reducing the possibility of displacement of the second welding wire 22 during subsequent stacking and / or lamination, thereby further improving the stability and reliability of the connection between the second welding wire 22 and the battery cell 1.

[0061] In one possible embodiment, during the process of applying glue to the second welding wire 22, the glue outlet can first be controlled to move along the first direction x and the second direction y so that the projection center of the glue outlet is aligned with the axis of the second welding wire 22 along the third direction z. The glue outlet is then controlled to move in the third direction z toward the second welding wire 22 to apply glue thereto for the first time. After the first application of glue is completed, the glue outlet is then controlled to move in the third direction z away from the second welding wire 22. Then, the glue outlet can be controlled to move only in the second direction y and again in the third direction z toward the edge of the long side to apply glue thereto for the second time. After the second application of glue is completed, the glue outlet is then controlled to move in the third direction z away from the edge of the long side. The above steps are then repeated so that the glue dots 3 are spaced apart along the second direction y on the upper surface of the second welding wire 22.

[0062] In a specific embodiment, during the process of curing the glue spot 3 so that the glue spot 3 covers the welding wire 2 and the battery cell 1, the preparation method further includes: performing thermal curing treatment on the glue spot 3, the temperature of the thermal curing treatment is T, and T satisfies 130℃≤T≤300℃.

[0063] In the embodiment of the present application, the glue point 3 can be a thermosetting glue. During the heating process of the glue point 3, the glue point 3 is affected by the high temperature in the initial stage of heating, so that its bonding performance is reduced and its fluidity is improved, so that the glue point 3 can flow along the outer surface of the welding wire 2 to the battery cell 1, so that the glue point 3 covers the welding wire 2 and the battery cell 1 at the same time. After subsequent curing, a fixed connection between the welding wire 2 and the battery cell 1 can be achieved, making it simple to operate and easy to implement.

[0064] Among them, the temperature of thermal curing treatment is T, and T can specifically be 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, 280℃, 285℃, 290℃, 295℃, 300℃, etc.

[0065] At the same time, when the temperature of the thermal curing treatment satisfies 130℃≤T≤300℃, the temperature is moderate, which can not only achieve the melting flow and curing connection of the glue point 3, but also avoid the risk of thermal damage to the battery cell 1 caused by excessively high temperature, which is beneficial to improving the safety of the battery cell 1 during the production process, thereby improving the production yield of the photovoltaic module.

[0066] The embodiment of the present application also provides a photovoltaic assembly, such as Figure 1 and Figure 3 As shown, the photovoltaic module includes a cell 1, a welding wire 2, and glue dots 3. The welding wire 2 is placed on the surface of one side of the cell 1 along the third direction z, and the glue dots 3 cover at least a portion of the welding wire 2 and the cell 1 along the third direction z. The glue dots 3 can be spaced apart along the second direction y and alternately cover the long edges on both sides of the first welding wire 21 along the first direction x. Alternatively, the glue dots 3 can be spaced apart along the second direction y and cover the upper surface of the second welding wire 22, with the projections of adjacent glue dots 3 along the second direction y overlapping.

[0067] In the embodiment of the present application, when the glue dots 3 are spaced apart along the second direction y and alternately cover the long side edges on both sides of the first welding wire 21 along the first direction x, such a design method can not only improve the stability and reliability of the connection between the first welding wire 21 and the battery cell 1, but also reduce the amount of glue used, thereby reducing the production cost of the photovoltaic module.

[0068] At the same time, the effective contact area between the first welding wire 21 and the grid line of the battery cell 1 can be increased, so that the two can be directly alloyed and connected better, which is beneficial to improving the current transmission efficiency and the photoelectric conversion efficiency of the photovoltaic module.

[0069] In addition, the glue points 3 alternately distributed along the first direction x can also improve the uniformity of the force applied to the first welding wire 21 to avoid stress concentration, thereby reducing the risk of the first welding wire 21 tilting, offsetting or warping during subsequent stacking and / or lamination, which is beneficial to improving the production yield of photovoltaic modules.

[0070] When the glue spots 3 are spaced apart and covered on the upper surface of the second welding wire 22 along the second direction y, and the projections of adjacent glue spots 3 along the second direction y overlap, such a design method can enable multiple spaced glue spots 3 to form a continuous bonding line along the second direction y, so as to improve the stability and reliability of the connection between the second welding wire 22 and the battery cell 1, thereby enabling the photovoltaic module to have strong mechanical reliability in harsh environments, so as to resist mechanical loads and vibrations, which is conducive to extending the service life of the photovoltaic module.

[0071] In one possible embodiment, the type of cell 1 used in the present application is a passivated emitter rear contact cell (Passivated Emitter Rear Cell, PERC), which uses a passivation film to passivate the back of the cell 1, replacing the all-aluminum back field of the traditional cell 1, to enhance the internal back reflection of light in the silicon substrate, thereby reducing the recombination rate on the back of the cell 1, so that it has a higher photoelectric conversion efficiency.

[0072] In one possible embodiment, the cell 1 used in the present application is a tunnel oxide passivated contact cell (TOPCon), which mainly includes an N-type single crystal silicon substrate, a tunnel dielectric layer formed by ultra-thin silicon oxide (SiOx) or silicon nitride (SiNx) deposited on the N-type single crystal silicon substrate, and a doped polysilicon layer covering the tunnel dielectric layer. The passivation effect of the tunnel dielectric layer enables electrons to reach the doped polysilicon layer or the N-type single crystal silicon substrate in contact with the tunnel dielectric layer through the tunnel effect, while blocking the passage of holes, reducing the recombination of electrons and holes at the interface, thereby forming selective carrier transmission, so that it has higher photoelectric conversion efficiency and stability, and lower attenuation rate.

[0073] In one possible embodiment, the type of cell 1 used in the present application is an intrinsic thin film heterojunction cell (Heterojunction with Intrinsic Thin-film, HJT, or, Heterojunction with Intrinsic Thin-layer, HIT). The cell 1 has a symmetrical double-sided cell structure, with N-type crystalline silicon in the middle, and an intrinsic amorphous silicon film and a P-type amorphous silicon film deposited in sequence on the front to form a PN junction, and an intrinsic amorphous silicon film and an N-type amorphous silicon film deposited in sequence on the back to form a back surface field. Due to the dual passivation effect of the N-type silicon substrate and amorphous silicon of the cell 1 on the surface defects of the substrate, it has a higher photoelectric conversion efficiency.

[0074] In one possible embodiment, the type of battery cell 1 used in the present application is a back contact battery (Back Contact, BC), and the bipolar metal grid lines (including bipolar main grid lines and bipolar fine grid lines) and the PN junction of the battery cell 1 are both arranged on the back of the battery cell 1, and the bipolar metal grid lines are distributed alternately at intervals, so that the front side (light-receiving side) of the battery cell 1 is not blocked by structures such as the bipolar metal grid lines, so that the front side of the battery cell 1 can be fully exposed to sunlight to maximize the light absorption area, which is beneficial to reduce optical loss and increase the short-circuit current Jsc; at the same time, the back side of the battery cell 1 can allow wider bipolar metal grid lines to reduce the series resistance Rs of the battery cell 1 to increase the fill factor FF; in addition, the front surface field of the battery cell 1 and the good passivation effect can increase the gain of the open circuit voltage, increase the output power of the battery cell 1, and make it have a higher photoelectric conversion efficiency.

[0075] In one possible embodiment, the type of cell 1 used in the present application is perovskite solar cells (PSCs), which is a new photovoltaic technology based on perovskite-type organic metal halide semiconductors. It uses a semiconductor material with an ABX3 structure to capture sunlight and convert it into electrical energy, where A is a bulky cation, B is a transition metal ion, and X is a halogen anion, which makes it have a lower production cost.

[0076] In one possible embodiment, the type of cell 1 used in the present application is a busbar-less cell (ZeroBusbar, 0BB). The cell 1 completely removes the front busbar so that the front side of the cell 1 can be completely exposed to sunlight to maximize the light absorption area, thereby helping to reduce optical losses and increase the short-circuit current Jsc; at the same time, the cell 1 retains the fine grid and back electrode, so that it has a higher photoelectric conversion efficiency and lower production cost.

[0077] In a specific embodiment, Figure 1 As shown, when the glue dots 3 are spaced apart along the second direction y and alternately cover the long side edges on both sides of the first welding wire 21 along the first direction x, the distance between adjacent glue dots 3 along the second direction y is L3, and L3 satisfies 12mm≤L3≤30mm.

[0078] In an embodiment of the present application, along the second direction y, the distance L3 between adjacent glue dots 3 can be specifically 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, etc.

[0079] When the distance between adjacent glue points 3 is too small (for example, L3 is less than 12 mm), the density of the glue points 3 located on the same side of the first welding wire 21 is too high, resulting in waste of glue, affecting the production cost of the photovoltaic module, and in a high temperature environment, it is also easy to cause the superposition of local thermal expansion stress, and there is a risk of causing hidden cracks in the battery cell 1, thereby affecting the safety and reliability of the photovoltaic module.

[0080] When the distance between adjacent glue points 3 is too large (for example, L3 is greater than 30 mm), the density of the glue points 3 located on the same side of the first welding wire 21 is too low, resulting in poor connection between the first welding wire 21 and the battery cell 1. During the subsequent stacking and / or lamination process, relative displacement is likely to occur between the two, thereby affecting the production yield of the photovoltaic module.

[0081] Therefore, along the second direction y, when the distance between adjacent glue spots 3 satisfies 12mm≤L3≤30mm, the density of the glue spots 3 located on the same side of the first welding wire 21 is moderate, which can ensure good connection stability between the first welding wire 21 and the battery cell 1, thereby improving the safety and reliability of the photovoltaic module during operation, and can also reduce the production cost of the photovoltaic module, which is more in line with actual production needs.

[0082] In a specific embodiment, Figure 1 As shown, when the glue dots 3 are spaced apart along the second direction y and alternately cover the long side edges on both sides of the first welding wire 21 along the first direction x, the distance between adjacent glue dots 3 along the first direction x is L5, and L5 satisfies 0.5mm≤L5≤1mm.

[0083] In the embodiment of the present application, along the first direction x, the gap L5 between adjacent glue dots 3 can specifically be 0.5mm, 0.52mm, 0.54mm, 0.56mm, 0.58mm, 0.6mm, 0.62mm, 0.64mm, 0.66mm, 0.68mm, 0.7mm, 0.72mm, 0.74mm, 0.76mm, 0.78mm, 0.8mm, 0.82mm, 0.84mm, 0.86mm, 0.88mm, 0.9mm, 0.92mm, 0.94mm, 0.96mm, 0.98mm, 1mm, etc.

[0084] When the distance between adjacent glue dots 3 is too small (for example, L5 is less than 0.5 mm), the contact area between the glue dots 3 and the first welding wire 21 on the long side edges on either side of the first welding wire 21 is too large, causing the glue dots 3 on the left long side edge and the glue dots 3 on the right long side edge to easily come into contact or even overlap, resulting in an excessive amount of glue being put into the glue dots 3 as a whole. In the subsequent stacking and / or lamination process, there is a risk that the glue dots 3 will overflow to the connection between the first welding wire 21 and the grid line, causing a cold solder joint.

[0085] When the distance between adjacent glue points 3 is too large (for example, L5 is greater than 1 mm), the contact area between the glue point 3 and the first welding wire 21 on the long side edge of either side of the first welding wire 21 is too small, resulting in poor connection between the first welding wire 21 and the battery cell 1. During the subsequent stacking and / or lamination process, relative displacement is likely to occur between the two, thereby affecting the production yield of the photovoltaic module.

[0086] Therefore, along the first direction x, when the distance between adjacent glue points 3 satisfies 0.5mm≤L5≤1mm, on the long side edge on either side of the first welding wire 21, the contact area between the glue point 3 and the first welding wire 21 is moderate, which can ensure good connection stability between the first welding wire 21 and the battery cell 1, and can also avoid the risk of cold welding at the connection between the first welding wire 21 and the grid line, thereby helping to improve the stability and reliability of the photovoltaic module during operation.

[0087] In a specific embodiment, Figure 3 As shown, when the glue dots 3 are spaced apart and covered on the upper surface of the second welding wire 22 along the second direction y, and the projections of adjacent glue dots 3 along the second direction y overlap, the distance between adjacent glue dots 3 along the second direction y is L4, and L4 satisfies 10mm≤L4≤20mm.

[0088] In an embodiment of the present application, along the second direction y, the distance L4 between adjacent glue dots 3 can be specifically 10mm, 10.5mm, 11mm, 11.5mm, 12mm, 12.5mm, 13mm, 13.5mm, 14mm, 14.5mm, 15mm, 15.5mm, 16mm, 16.5mm, 17mm, 17.5mm, 18mm, 18.5mm, 19mm, 19.5mm, 20mm, etc.

[0089] When the distance between adjacent glue dots 3 is too small (for example, L4 is less than 10 mm), the density of the glue dots 3 covering the second welding wire 22 is too high, resulting in an excessive amount of glue being put into the glue dots 3 as a whole, and accumulation is likely to occur between adjacent glue dots 3. As a result, during the subsequent stacking and / or lamination process, there is a risk that the glue dots 3 will overflow to the connection between the first welding wire 21 and the grid line, causing a cold solder joint.

[0090] When the distance between adjacent glue points 3 is too large (for example, L4 is greater than 20 mm), the density of the glue points 3 covering the second welding wire 22 is too low, resulting in poor connection between the second welding wire 22 and the battery cell 1. During the subsequent stacking and / or lamination process, relative displacement is likely to occur between the two, thereby affecting the production yield of the photovoltaic module.

[0091] Therefore, along the second direction y, when the distance between adjacent glue dots 3 satisfies 10mm≤L4≤20mm, the density of the glue dots 3 covering the second welding wire 22 is moderate, so that adjacent glue dots 3 are relatively independently distributed, thereby reducing the possibility of accumulation and fusion between adjacent glue dots 3. This ensures that the glue dots 3 effectively cover the second welding wire 22 and the solar cell 1, thereby improving the stability and reliability of the connection between the two. At the same time, it also avoids the risk of glue dots 3 overflowing to the connection between the second welding wire 22 and the grid line, causing a cold weld. This ensures the working performance of the photovoltaic module while reducing the production cost of the photovoltaic module, and better meets actual production needs.

[0092] In a specific embodiment, Figure 2 and Figure 4 As shown, the surface of the welding wire 2 is provided with a receiving groove 23 and a guide groove 24. The receiving grooves 23 are spaced apart along the second direction y, and the guide groove 24 is located on at least one side of the receiving groove 23 along the first direction x and is connected to the side wall of the receiving groove 23.

[0093] In the embodiments of the present application, the accommodation groove 23 is used to limit the spread of the glue point 3, so that the glue point 3 can be stably attached to the upper surface of the welding wire 2, to avoid the risk of spreading along the outer surface of the welding wire 2 before solidification (for example, during the process of transporting the welding wire 2), thereby improving the adhesion effect of the glue point 3 on the surface of the welding wire 2. The guide groove 24 is used to guide the flow of the glue point 3, providing a flow passage for the flow of the glue point 3, to ensure that the glue point 3 can uniformly spread along the outer surface of the welding wire 2 before complete solidification, realizing the common coverage of the welding wire 2 and the battery piece 1, and being beneficial to improve the stability and reliability of the connection between the welding wire 2 and the battery piece 1.

[0094] The accommodation groove 23 is arranged on the welding wire 2, so as to provide a coordinate point for the projection center of the glue outlet during the gluing process, to improve the positioning accuracy during gluing, improve the uniformity of the distribution of the glue point 3 on the welding wire 2, ensure that the coverage rate of the glue point 3 on the welding wire 2 is moderate, and avoid the risk of local concentration of the glue point 3 on the welding wire 2 and other adverse phenomena, to prepare for the fixed connection between the welding wire 2 and the battery piece 1.

[0095] At the same time, the accommodation groove 23 can also limit the volume of the glue point 3, to avoid waste caused by excessive amount of glue, thereby being beneficial to reduce the production cost.

[0096] In addition, by arranging the accommodation groove 23 and the guide groove 24, the glue point 3 and the surface of the welding wire 2 can form a more close fitting, which is beneficial to further improve the bonding effect between the glue point 3 and the welding wire 2, and reduce the risk of glue point 3 falling off or premature spread due to external force or vibration and other factors.

[0097] In a possible implementation, when the accommodation groove 23 and the guide groove 24 are arranged on the first welding wire 21, the accommodation grooves 23 are distributed along the second direction y and are alternately distributed near the long edge edges on both sides of the first welding wire 21 along the first direction x; the guide groove 24 is located on the side of the accommodation groove 23 close to the long edge edge adjacent to the accommodation groove 23, and is in communication with the side wall of the accommodation groove 23, so that the guide groove 24 can guide the glue point 3 in one direction.

[0098] In a possible implementation, when the accommodation groove 23 and the guide groove 24 are arranged on the second welding wire 22, the accommodation grooves 23 are distributed along the second direction y, and the projection of the accommodation groove 23 and the second welding wire 22 axis along the third direction z overlaps; the guide grooves 24 are located on both sides of the accommodation groove 23 and are symmetrically distributed relative to the accommodation groove 23, and both of the guide grooves 24 are in communication with the side wall of the accommodation groove 23, so that the guide grooves 24 can guide the glue point 3 in two directions.

[0099] In a possible implementation, the accommodation groove 23 and the guide groove 24 can be processed by laser processing or etching and the like.

[0100] In one possible embodiment, a gap exists between the bottom wall of the guide groove 24 and the bottom wall of the receiving groove 23 along the third direction z. That is, the bottom wall of the guide groove 24 is located on the side of the bottom wall of the receiving groove 23 facing away from the battery cell 1, so that there is a height difference between the two. This design allows at least a portion of the glue dot 3 to remain within the receiving groove 23 at all times, allowing it to connect with the portion that has spread to the battery cell 1 through the guide groove 24, thereby achieving a fixed connection between the welding wire 2 and the battery cell 1.

[0101] In a specific embodiment, Figure 2 and Figure 4 As shown, along the third direction z, the guide groove 24 is inclined relative to the receiving groove 23 toward the direction close to the battery cell 1, and an angle α is formed between the bottom wall of the guide groove 24 and the bottom wall of the receiving groove 23, and α satisfies 5°≤α≤30°.

[0102] In the embodiment of the present application, by providing the guide groove 24 with an inclination relative to the receiving groove 23 along the third direction z toward the direction closer to the cell 1, gravity can be utilized to facilitate the smooth flow of the glue dots 3, thereby reducing the possibility of accumulation or blockage of the glue dots 3 when flowing within the guide groove 24 and improving the flow efficiency of the glue dots 3. This ensures that the glue dots 3 flow to the surface of the cell 1 before fully solidifying, thereby ensuring the production yield of the photovoltaic module. Furthermore, when the angle α between the bottom wall of the guide groove 24 and the bottom wall of the receiving groove 23 satisfies 5°≤α≤30°, the fluidity of the glue dots 3 can be balanced, allowing the glue dots 3 to evenly cover the bottom wall of the guide groove 24 during flow. This ensures that the glue dots 3 have good structural stability after solidification, thereby ensuring the connection effect of the glue dots 3 between the welding wire 2 and the cell 1.

[0103] Among them, the angle α between the bottom wall of the guide groove 24 and the bottom wall of the accommodating groove 23 can be 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, etc.

[0104] In a specific embodiment, the material of the glue point 3 is epoxy resin or polyurethane, the thixotropic index of the glue point 3 is TI, and TI satisfies TI>4.

[0105] In the embodiment of the present application, by setting the thixotropic index TI of the glue point 3 to TI satisfying TI>4, the glue point 3 can have a higher viscosity in a static state (i.e. before curing), thereby improving the bonding effect between the glue point 3 and the upper surface of the welding wire 2, and reducing the possibility of the glue point 3 sagging or dripping during the process of transporting the welding wire 2 to the battery cell 1, thereby reducing the number of rework glue coating times and improving the overall production efficiency of the photovoltaic module.

[0106] The glue point 3 may be epoxy resin, which has high bonding strength and service life, so as to improve the stability and reliability of the connection between the welding wire 2 and the battery cell 1 .

[0107] At the same time, the glue point 3 can also be polyurethane, so that it has good elastic deformation ability to relieve the pressure during subsequent stacking and / or lamination, reduce the possibility of breakage of the glue point 3 after curing, and thus ensure the connection effect between the welding wire 2 and the battery cell 1.

[0108] The above describes in detail the structure, features and effects of the present application based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present application, but the present application does not limit the scope of implementation to what is shown in the drawings. Any changes made in accordance with the concept of the present application, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present application.

Claims

1. A method for preparing a photovoltaic module, characterized in that: The preparation method comprises: Apply glue dots on the surface of the welding wire; Transferring the welding wire to the surface of the battery cell; curing the glue point so that the glue point covers the welding wire and the battery cell; Stacking the front cover plate, the front adhesive film, the battery cell, the back adhesive film and the back cover plate to form a stacked assembly; laminating the stacked assembly to form a laminated assembly; The viscosity of the glue point is η, and η satisfies 6000 mPa·s≤η≤10000 mPa·s.

2. The preparation method according to claim 1, characterized in that The welding wire includes a first welding wire, and the glue dots are coated on the surface of the first welding wire through a glue outlet. When the glue dots are coated on the surface of the first welding wire, the preparation method further includes: Detecting the width L1 of the first welding wire, where L1 satisfies 1 mm ≤ L1 ≤ 1.5 mm; Moving the projection center of the glue outlet along the first direction x and the second direction y until it is aligned with the long side edge of one side of the first welding wire along the third direction z, and applying glue dots; Moving the projection center of the glue outlet along the first direction x and the second direction y until it is aligned with the long side edge of the other side of the first welding wire along the third direction z, and applying glue dots; Repeat the above steps so that the glue dots are distributed at intervals along the second direction y and alternately cover the long side edges on both sides of the first welding wire along the first direction x.

3. The preparation method according to claim 1, characterized in that The welding wire includes a second welding wire, and the glue dots are coated on the surface of the second welding wire through a glue outlet. When the glue dots are coated on the surface of the second welding wire, the preparation method further includes: Detecting a width L2 of the second welding wire, where L2 satisfies 0.2 mm ≤ L2 ≤ 0.3 mm; Moving the projection center of the glue outlet along the first direction x and the second direction y until it is aligned with the axis of the second welding wire along the third direction z, and applying glue dots; Repeat the above steps so that the glue dots cover the upper surface of the second welding wire at intervals along the second direction y, and the projections of adjacent glue dots along the second direction y overlap.

4. The preparation method according to any one of claims 1 to 3, characterized in that In the process of curing the glue point so that the glue point covers the welding wire and the battery cell, the preparation method further includes: The glue point is subjected to a heat curing treatment, the temperature of the heat curing treatment is T, and T satisfies 130°C≤T≤300°C.

5. A photovoltaic module, manufactured by the preparation method according to any one of claims 1 to 4, characterized in that: The photovoltaic module comprises: Battery cells; Welding wire, placed on the surface of the battery cell; glue dots, the glue dots covering the welding wire and the battery cell; The glue spots are spaced apart along the second direction y and alternately cover the long side edges on both sides of the welding wire along the first direction x, or the glue spots are spaced apart along the second direction y and cover the upper surface of the welding wire, and the projections of adjacent glue spots along the second direction y overlap.

6. The photovoltaic module according to claim 5, characterized in that: The welding wire includes a first welding wire. Along the second direction y, the distance between adjacent glue spots is L3, and L3 satisfies 12mm≤L3≤30mm. Along the first direction x, the distance between adjacent glue spots is L5, and L5 satisfies 0.5mm≤L5≤1mm.

7. The photovoltaic module according to claim 5, characterized in that The welding wire includes a second welding wire. Along the second direction y, the distance between adjacent glue points is L4, and L4 satisfies 10mm≤L4≤20mm.

8. The photovoltaic module according to any one of claims 5 to 7, characterized in that: The surface of the welding wire is provided with a receiving groove and a guide groove, the receiving grooves are spaced apart along the second direction y, and the guide groove is located on at least one side of the receiving groove along the first direction x and is connected to the side wall of the receiving groove.

9. The photovoltaic module according to claim 8, characterized in that: Along the third direction z, the guide groove is inclined relative to the receiving groove toward the direction close to the battery cell, and an angle α is formed between the bottom wall of the guide groove and the bottom wall of the receiving groove, and α satisfies 5°≤α≤30°.

10. The photovoltaic module according to any one of claims 5 to 7, characterized in that: The material of the glue point is epoxy resin or polyurethane, the thixotropic index of the glue point is TI, and TI satisfies TI>4.

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