Photovoltaic module and preparation method thereof

Abstract

The invention provides a photovoltaic module and a preparation method thereof, and relates to the technical field of back contact cells. On the back face of a first battery piece of the photovoltaic module, an insulating strip covers the first sections of a plurality of first polarity welding strips and the ends of a plurality of second polarity welding strips, the second sections of the first polarity welding strips and a bus bar are arranged on the side, away from the first battery piece, of the insulating strip, and the bus bar is connected with the second sections. And the bent section of the first polarity welding strip is connected with the first section and the second section respectively. The insulating strip does not exceed the edge of the first battery piece, and the end part of the first polarity welding strip does not exceed the edge of the first battery piece. And the second battery piece is connected with the bus bar on the first battery piece. The two adjacent battery pieces are seamlessly spliced through the mode that the welding strips are bent and connected with the bus bars, hiding of the bus bars is achieved in the photovoltaic module, the photovoltaic module is simple in structure, the technology is simplified, and cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of back-contact cells, and in particular to a photovoltaic module and a method for preparing the same. Background Art

[0002] Back-contact cells are a key area of ​​solar cell technology. Using back-contact cells in photovoltaic modules facilitates concealing busbars, allowing for more cells to be packed into the same form factor, thereby increasing module efficiency. However, concealing busbars in the ends and middle of photovoltaic modules presents complex manufacturing processes and high costs. Summary of the Invention

[0003] This application proposes a photovoltaic module and a preparation method thereof, which aims to hide the bus bar between two adjacent solar cells, simplify the process and reduce costs.

[0004] In a first aspect, the present application provides a photovoltaic module comprising a plurality of cells, a plurality of first polarity welding ribbons and a plurality of second polarity welding ribbons, an insulating strip and a bus bar.

[0005] The plurality of cells include a first cell and a second cell, each cell having a front side and a back side facing each other. A plurality of first polarity welding ribbons and a plurality of second polarity welding ribbons are disposed on the back side of the cell, the first polarity welding ribbons and the second polarity welding ribbons being alternately arranged along a first direction parallel to the back side. Insulation strips and bus bars are disposed on the back side of the cell.

[0006] On the first cell, the end of the first polarity welding ribbon includes a first section, a second section, and a bent section. The first section is located on the back of the first cell, and the insulating strip covers the first sections of multiple first polarity welding ribbons and the ends of multiple second polarity welding ribbons. The bent section is connected to the first section and bends along the side of the insulating strip to the side of the insulating strip away from the first cell. The second section and the bus bar are both located on the side of the insulating strip away from the first cell, with the second section connected to the bent section, and the bus bar connected to the second section.

[0007] Along a second direction parallel to the back surface, the insulating strip does not exceed the edge of the first battery cell, and the end of the first polarity welding strip does not exceed the edge of the first battery cell. The second direction intersects the first direction.

[0008] The second battery cell is connected to the bus bar on the first battery cell.

[0009] In some embodiments, along the second direction, a reference distance exists between a side surface of the insulating strip close to the bending segment and an edge of the first solar cell.

[0010] In some embodiments, the bent segment contacts a side surface of the insulating strip, and a thickness of the bent segment along a direction perpendicular to the side surface of the insulating strip is less than or equal to a reference spacing.

[0011] In some embodiments, among the first segment, the second segment, and the bending segment, at least the bending segment is made of a flexible conductive material.

[0012] In some embodiments, the flexible conductive material includes a metal foil.

[0013] In some embodiments, the photovoltaic module further includes a buffer layer disposed between the first segment and the second segment.

[0014] In some embodiments, the orthographic projection of the bus bar on the back side is within the range of the orthographic projection of the insulating strip on the back side. Along the second direction, the width of the insulating strip is greater than or equal to the width of the bus bar.

[0015] In some embodiments, the first cell and the second cell are disposed adjacent to each other along the second direction. Along the second direction, the end of the first polarity welding ribbon is disposed at an edge of the first cell proximate to the second cell. On the second cell, the end of the first polarity welding ribbon proximate to the first cell extends beyond the edge of the second cell and is connected to a busbar on the first cell.

[0016] In some embodiments, the first cell and the second cell are adjacently arranged along a first direction, the bus bar extends from the first cell to the second cell along the first direction, and the second polarity welding ribbon is connected to the bus bar on the second cell.

[0017] In some embodiments, the bus bar is located on a side of the second segment away from the insulating strip, or the bus bar is located between the insulating strip and the second segment.

[0018] In a second aspect, the present application further provides a method for preparing a photovoltaic module, comprising the following steps S01 to S05:

[0019] Step S01: multiple first polarity welding strips and multiple second polarity welding strips are arranged on the back side of the first battery cell. The first polarity welding strips and the second polarity welding strips are alternately arranged along a first direction parallel to the back side. One end of the first polarity welding strip extends beyond the edge of the first battery cell along a second direction parallel to the back side. The second direction intersects with the first direction.

[0020] Step S02: an insulating strip is provided on the back side of the first cell, the insulating strip covering ends of the plurality of first polarity welding strips and the plurality of second polarity welding strips, and the insulating strip does not exceed the edge of the first cell along the second direction.

[0021] Step S03: Connecting the bus bar to the first polarity welding ribbon, wherein the bus bar is connected to the end of the first polarity welding ribbon that exceeds the edge of the first battery cell.

[0022] Step S04: bend the end of the first polarity welding strip that exceeds the edge of the first battery cell so that the bus bar is located on the side of the insulating strip away from the first battery cell; along the second direction, the bent end of the first polarity welding strip does not exceed the edge of the first battery cell.

[0023] Step S05: Connect the second battery cell to the bus bar on the first battery cell.

[0024] In some embodiments, along the second direction, the difference between the length of the first polarity welding ribbon extending beyond the edge of the first battery cell and the width of the bus bar is greater than or equal to 2 mm.

[0025] In the embodiments provided herein, a plurality of first polarity welding strips and a plurality of second polarity welding strips are arranged on the back of a battery cell. The first polarity welding strips and the second polarity welding strips are arranged alternately along a first direction parallel to the back, and the insulating strips and bus bars are also arranged on the back of the battery cell. On the first battery cell, the end of the first polarity welding strip includes a first section, a second section, and a bent section. The first section is arranged on the back of the first battery cell, and the insulating strip covers the first sections of the plurality of first polarity welding strips and the ends of the plurality of second polarity welding strips. The bent section is connected to the first section, and the bent section is bent through the side of the insulating strip to the side of the insulating strip away from the first battery cell. The second section and the bus bar are both arranged on the side of the insulating strip away from the first battery cell, the second section is connected to the bent section, and the bus bar is connected to the second section.

[0026] That is, on the back side of the first cell, the insulating strip covers the first sections of the plurality of first polarity welding strips and covers the ends of the plurality of second polarity welding strips. The second section and the bent section of the first polarity welding strip extend beyond the coverage of the insulating strip, and the second section is connected to the bus bar. The bent section is used to bend the second section and the bus bar to the side of the insulating strip away from the first section, thereby achieving electrical connection between the first polarity welding strip and the bus bar and insulation between the second polarity welding strip and the bus bar. The ends of the bus bar, the insulating strip, and the first polarity welding strip do not extend beyond the edge of the first cell. The second cell is connected to the bus bar on the first cell. In the photovoltaic module thus formed, the second cell can be seamlessly spliced ​​with the first cell, that is, the bus bar is hidden in the photovoltaic module. Two adjacent cells are seamlessly spliced, and more cells can be placed in the same layout, thereby increasing the efficiency of the photovoltaic module. In addition, the photovoltaic module provided by the embodiment of the present application has a simple structure, which is conducive to simplifying the process and reducing costs.

[0027] The preparation method provided in this application can be used to prepare the photovoltaic module in the aforementioned first aspect embodiment. The prepared photovoltaic module has the aforementioned beneficial effects, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] To more clearly illustrate the technical solutions of this application, the following briefly introduces the drawings required for use in some embodiments of this application. Obviously, the drawings described below are only drawings of some embodiments of this application. For those skilled in the art, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and do not represent the actual dimensions of the products or the actual processes of the methods involved in the embodiments of this application.

[0029] Figure 1 A schematic diagram of a partial structure of a photovoltaic module provided in an embodiment of the present application;

[0030] Figure 2 for Figure 1 A cross-sectional view of the photovoltaic module shown along section line AA';

[0031] Figure 3 for Figure 1 A partial enlarged view of the photovoltaic module at position M is shown;

[0032] Figure 4 for Figure 1 Another cross-sectional view of the photovoltaic module along the section line AA';

[0033] Figure 5 A schematic structural diagram of another photovoltaic module provided in an embodiment of the present application;

[0034] Figure 6 A flow chart of a method for preparing a photovoltaic module provided in an embodiment of the present application;

[0035] Figures 7 to 10 for Figure 6 Diagram of each step of the preparation method. DETAILED DESCRIPTION

[0036] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present application. Obviously, the embodiments described are only some embodiments of the present application, not all embodiments. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0037] Unless the context requires otherwise, throughout the specification and claims, the term "comprising" is to be construed in an open, inclusive sense, that is, meaning "including, but not limited to."

[0038] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of this application, unless otherwise specified, "plurality" means two or more.

[0039] When describing some embodiments, the word "connected" and its derivatives may be used. The term "connected" should be understood broadly. For example, "connected" can mean fixed connection, detachable connection, or integration; it can be directly connected or indirectly connected through an intermediate medium. For example, when describing some embodiments, the term "connected" may be used to indicate that two or more components are in direct physical or electrical contact with each other.

[0040] Additionally, the use of “based on” is meant to be open and inclusive, as a process, step, calculation, or other action “based on” one or more stated conditions or values ​​may, in practice, be based on additional conditions or values ​​beyond those stated.

[0041] Exemplary embodiments are described herein with reference to cross-sectional views that are idealized exemplary drawings. In the drawings, the thickness of layers and the areas of regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are contemplated. Therefore, the exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include deviations in shape due to, for example, manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device and are not intended to limit the scope of the exemplary embodiments.

[0042] With the continuous advancement of photovoltaic technology, the use of back-contact cells to hide the busbars in photovoltaic modules, thereby placing more cells in the same layout to increase module efficiency, is a development trend in this field. In back-contact cells, the grid lines of different polarities of the cell (including the main grid and the auxiliary grid) are all located on the back of the cell, and the busbar is located on the side of all the grid lines away from the front of the cell. Taking the corresponding electrical connection between the busbar and the positive grid line of a certain cell as an example, at this busbar, it is necessary to ensure the electrical connection between the positive main grid and the positive auxiliary grid, the electrical connection between the positive main grid and the busbar, the electrical connection between the negative main grid and the negative auxiliary grid, as well as the electrical isolation between the negative main grid and the positive auxiliary grid, the electrical isolation between the positive main grid and the negative auxiliary grid, and the electrical isolation between the negative main grid and the busbar.

[0043] This results in a complex insulation design near the busbar for the cell, a cumbersome process, and high manufacturing costs. Furthermore, when using solder ribbon to electrically connect the busbar to the positive grid line, the solder joint is hidden between the contact surface of the cell and the busbar, posing a risk of damaging the cell during the soldering process.

[0044] Based on this, the present application provides a photovoltaic module, such as Figures 1 to 3 As shown, Figure 1 A schematic diagram of a partial structure of a photovoltaic module provided in an embodiment of the present application is shown. Figure 2 for Figure 1 A cross-sectional view of the photovoltaic module shown along the section line AA', Figure 3 for Figure 1 A partial enlarged view of the photovoltaic module at position M is shown.

[0045] It can be understood that the photovoltaic module 10 includes multiple battery strings, each battery string includes multiple battery cells, and the multiple battery cells inside the battery string are connected in series through welding ribbons, and the battery strings are connected in series or in parallel through bus bars on the battery cells located at both ends of the battery string.

[0046] In the embodiment of the present application, the cells electrically connected between two adjacent cell strings in the photovoltaic module 10 are respectively referred to as a first cell 11 and a second cell 12 .

[0047] like Figure 1 As shown, the photovoltaic assembly 10 further includes a plurality of first polarity welding ribbons 21 and a plurality of second polarity welding ribbons 22 , an insulating strip 31 and a bus bar 32 .

[0048] The battery cell includes a front side P1 and a back side P2 relative to each other. A plurality of first polarity welding strips 21 and a plurality of second polarity welding strips 22 are arranged on the back side P2 of the battery cell. The first polarity welding strips 21 and the second polarity welding strips 22 are arranged alternately along a first direction X parallel to the back side P2. That is, the battery cell is a back-contact battery.

[0049] In the embodiment of the present application, the welding strips are divided into first polarity welding strips 21 and second polarity welding strips 22 according to the charged polarity of the welding strips. For example, the first polarity welding strip 21 corresponds to the first polarity grid line (for example, the positive main grid) on the battery cell, and the second polarity welding strip 22 corresponds to the second polarity grid line (for example, the negative main grid) on the battery cell.

[0050] It is understandable that on a battery string, the welding ribbons can also be divided into lead-out welding ribbons and non-lead-out welding ribbons according to the working properties of the welding ribbons. The lead-out welding ribbons are used to electrically connect to the busbars, and the non-lead-out welding ribbons are used to achieve the series connection between two adjacent battery cells within the battery string. That is, within the battery string, a non-lead-out welding ribbon corresponds to the first polarity welding ribbon 21 on one battery cell and the second polarity welding ribbon 22 on the other adjacent battery cell. For the two battery cells at the end of a battery string, the lead-out welding ribbon on one battery cell corresponds to the first polarity welding ribbon 21, and the lead-out welding ribbon on the other battery cell corresponds to the second polarity welding ribbon 22.

[0051] In the embodiment of the present application, the insulating strips 31 and the bus bars 32 are also disposed on the back surface P2 of the cell.

[0052] like Figure 2 As shown, taking the first polarity lead-out end of the battery string as an example, on the first battery cell 11, the end of the first polarity welding strip 21 includes a first section 211, a second section 212 and a bent section 213, the first section 211 is arranged on the back side P2 of the first battery cell 11, and the insulating strip 31 covers the first sections 211 of multiple first polarity welding strips 21 and the ends of multiple second polarity welding strips 22.

[0053] The bent section 213 is connected to the first section 211 and bends along the side of the insulating strip 31 to the side of the insulating strip 31 away from the first battery cell 11. The second section 212 and the bus bar 32 are both disposed on the side of the insulating strip 31 away from the first battery cell 11. The second section 212 is connected to the bent section 213, and the bus bar 32 is connected to the second section 212.

[0054] For example, the busbar 32 is connected to the second section 212 by welding, and the bent section 213 can reduce thermal deformation caused by the welding process, thereby improving the reliability and stability of the welding between the busbar 32 and the second section 212 .

[0055] like Figure 1 and Figure 2 As shown, the second direction Y intersects the first direction X. Along the second direction Y parallel to the back surface P2, the insulating strip 31 does not exceed the edge of the first battery cell 11. That is, along the second direction Y, the orthographic projection of the insulating strip 31 on the back surface P2 is located within the range of the first battery cell 11. In addition, the end of the first polarity welding strip 21 does not exceed the edge of the first battery cell 11. Figure 2 It can be seen that the orthographic projection of the outermost side of the bent section 213 on the back surface P2 is also located within the range of the first battery cell 11 .

[0056] The second section 212 and the bus bar 32 are both arranged on the side of the insulating strip 31 away from the first battery cell 11. Along the second direction Y, the orthographic projections of the bent section 213 and the insulating strip 31 on the back side P2 are both located within the range of the first battery cell 11. Based on this, when the second battery cell 12 and the first battery cell 11 are arranged and electrically connected along the second direction Y, for example, two battery strings are connected in parallel along the second direction Y. Since the structures that need to be electrically isolated on the two adjacent battery cells do not exceed the orthographic projection range of the battery cells, there is no need to reserve space for related structures at the joint of the two battery cells. The second battery cell 12 and the first battery cell 11 can be seamlessly spliced, and the bus bar 32 can be completely hidden on the back side of the photovoltaic module 10. In the photovoltaic module 10 of the same version, more battery cells can be placed along the second direction Y to increase the efficiency of the photovoltaic module 10. Similarly, when the second cell 12 is arranged and electrically connected to the first cell 11 along the first direction X, for example, two cell strings are connected in series along the first direction X, the second cell 12 can adopt a design similar to that of the first cell 11. Along the second direction Y, the welding strips and bus bars 32 on the two cell slices do not exceed the boundaries of the cell slices. Therefore, the photovoltaic module 10 does not need to add additional space along the second direction Y for insulation protection, which is conducive to reducing the size of the photovoltaic module 10.

[0057] like Figure 3 As shown, taking the first polarity welding ribbon 21 corresponding to the first polarity grid line and the second polarity welding ribbon 22 corresponding to the second polarity grid line as an example, the first battery cell 11 also includes multiple first polarity sub-grids 101 and second polarity sub-grids 102 extending along the first direction X. Along the second direction Y, the first polarity welding ribbon 21 is electrically connected to the multiple first polarity main grids 103, thereby realizing the electrical lead-out of the first polarity grid line. Similarly, the second polarity welding ribbon 22 is electrically connected to the multiple second polarity main grids 104, thereby realizing the electrical lead-out of the second polarity grid line.

[0058] In order to prevent short circuit, insulating glue 105 needs to be provided at the intersection of the second polarity auxiliary grid 102 and the first polarity welding strip 21 , and at the intersection of the first polarity auxiliary grid 101 and the second polarity welding strip 22 .

[0059] Typically, along the second direction Y, the spacing between the first polarity sub-grid 101 and the second polarity sub-grid 102 is much smaller than the width of the busbar 32, meaning that the busbar 32 covers multiple first polarity sub-grids 101 and second polarity sub-grids 102. In view of the feature of "alternating first polarity welding ribbons 21 and second polarity welding ribbons 22," at the busbar 32, to ensure electrical connection between the busbar 32 and the first polarity welding ribbon 21, electrical isolation between the busbar 32 and the second polarity welding ribbon 22, and electrical isolation between the busbar 32 and the second polarity sub-grid 102, the insulation design in the related art is interwoven and complex, and insulating glue is also required between the second polarity sub-grid 102 and the busbar for isolation.

[0060] In the embodiment of the present application, the insulating strip 31 is provided throughout the entire length. For example, the insulating strip 31 extends along the first direction X. On the first cell 11, the insulating strip 31 does not extend beyond the boundary of the first cell 11. Alternatively, on the photovoltaic module 10, multiple cells are arranged in an array, and the insulating strip 31 extends along the first direction X. The insulating strip 31 covers multiple cells corresponding to a row in the array, does not extend beyond the boundary of the photovoltaic module 10 along the first direction X, and can also cover the first sections 211 of the multiple first polarity welding ribbons 21 and the ends of the multiple second polarity welding ribbons 22 on each cell.

[0061] It is understandable that, on the first battery cell 11 , the insulating strip 31 extends outward based on the outer boundaries of the two outermost welding strips along the first direction X. The redundant design can reserve a margin for process errors and avoid short circuits.

[0062] The insulating strip 31 covers the first segments 211 of the plurality of first polarity welding ribbons 21 and the ends of the plurality of second polarity welding ribbons 22. The bus bar 32 is disposed on the side of the insulating strip 31 away from the first cell 11, thereby electrically isolating the bus bar 32 from the second polarity welding ribbons 22 and the second polarity auxiliary grid 102. Compared to the related art, the portion of the second polarity auxiliary grid 102 located between the first polarity welding ribbon 21 and the second polarity welding ribbon 22 does not require additional insulating adhesive. Moreover, since the bus bar 32 and the first polarity welding ribbon 21 are electrically connected via the second segment 212 and the bent segment 213, when considering the insulation design between the bus bar 32 and the second polarity welding ribbon 22, the insulating strip 31 can be provided throughout the entire length, rather than being discretely arranged according to the alternating arrangement of the first polarity welding ribbon 21 and the second polarity welding ribbon 22. The insulation design of the present application is simpler, which helps to simplify the corresponding process and reduce costs.

[0063] Furthermore, in the design of achieving the electrical connection between the bus bar 32 and the first polarity welding ribbon 21, the second section 212 of the first polarity welding ribbon 21 can be extended beyond the edge of the first cell 11, and the second section 212 and the bus bar 32 can be welded outside the first cell 11. The second section 212 and the bus bar 32 can then be bent, that is, the second section 212 and the bus bar 32 can be bent onto the insulating strip 31 using the bending section 213. This solution not only achieves the electrical connection between the first polarity welding ribbon 21 and the bus bar 32, but also allows the bus bar 32 and the first polarity welding ribbon 21 to be bent back into the range of the first cell 11, ensuring that the relevant structures in the final product do not exceed the edge of the first cell 11.

[0064] The above method is not only simple in process and easy to operate, but also facilitates the modular production of the photovoltaic module 10 and the seamless splicing of two adjacent solar cells.

[0065] For example, combined with Figure 1 Taking the second battery cell 12 and the first battery cell 11 as an example where they are arranged along the second direction Y and connected in parallel, when the bus bar 32 of the first battery cell 11 is bent back into the range of the first battery cell 11, the second battery cell 12 and the first battery cell 11 are seamlessly spliced ​​together, and then it is only necessary to extend the first polarity welding strip 21 of the second battery cell 12 on its back side to electrically connect with the bus bar 32 of the first battery cell 11.

[0066] Based on the above-mentioned solution of this application, no additional insulation design is required during the splicing process of the two cells, which simplifies the process and reduces costs. The two cells are seamlessly spliced, and the busbar 32 is completely hidden on the back of the photovoltaic module 10. In the same format of photovoltaic module 10, more cells can be placed, thereby increasing the efficiency of the photovoltaic module 10.

[0067] In some embodiments, as Figures 1 to 3 As shown, along the second direction Y, a reference distance D1 is formed between the side surface of the insulating strip 31 close to the bending section 213 and the edge of the first battery cell 11. The reference distance D1 reserves space for the bending section 213 to not exceed the edge of the first battery cell 11 after bending.

[0068] like Figure 2 As shown, to prevent the cell from being broken due to a too small bending radius (or to prevent the bending section 213 from being broken), and considering the size of the first polarity welding ribbon 21 itself (for example, the thickness of the bending section 213 along the second direction Y), there is usually a relative distance D2 between the outermost side of the bending section 213 and the side surface of the insulating strip 31. In other words, the relative distance D2 is related to the thickness of the bending section 213 along the second direction Y and the bending radius.

[0069] In this embodiment, the reference distance D1 is reasonably set so that D1 ≥ D2, thereby ensuring that the end of the first polarity welding ribbon 21 does not exceed the edge of the first battery cell 11.

[0070] In some embodiments, as Figure 4 As shown, Figure 4 for Figure 1 Another cross-sectional view of the photovoltaic module along section line AA′ is shown. The bent section 213 contacts the side surface of the insulating strip 31 , and along a direction perpendicular to the side surface of the insulating strip 31 , the thickness D3 of the bent section 213 is less than or equal to the reference distance D1 .

[0071] Combine Figure 4 , it can be understood that the bending radius of the bent section 213 relative to the side of the insulating strip 31 is 0, the inner side of the bent section 213 is adjacent to the side of the insulating strip 31, and the distance between the outermost side of the bent section 213 and the side of the insulating strip 31 is the thickness D3 of the bent section 213. D3 is less than or equal to the reference distance D1, thereby ensuring that the end of the first polarity welding ribbon 21 does not extend beyond the edge of the first solar cell 11.

[0072] Based on this, at the joint of the two battery cells, there is no structure such as welding strips between the edges of the two battery cells. The two battery cells can be seamlessly spliced, and the bus bar 32 is completely hidden on the back of the photovoltaic module 10. In the same version of the photovoltaic module 10, more battery cells can be placed to increase the efficiency of the photovoltaic module 10.

[0073] In some embodiments, reference Figure 4 Among the first section 211, the second section 212, and the bent section 213, at least the bent section 213 may be made of a flexible conductive material. For example, only the bent section 213 may be made of a flexible conductive material, or both the second section 212 and the bent section 213 may be made of a flexible conductive material, or both the first section 211 and the bent section 213 may be made of a flexible conductive material, or, alternatively, all three of the first section 211, the second section 212, and the bent section 213 may be made of a flexible conductive material.

[0074] Flexible conductive materials are soft and relatively thin, making them more susceptible to deformation and, therefore, easier to bend. For example, as mentioned above, the second section 212 and the busbar 32 are welded outside the first cell 11, and then bent onto the insulating strip 31 using the bending section 213. Because the bending section 213 is made of a flexible conductive material, there is essentially no curvature after bending. After bending, the dimension of the bending section 213 along the thickness direction Z can be flush with the busbar 32, allowing the busbar 32 to be arranged parallel to the insulating strip 31. The characteristics of the flexible conductive material make the stress concentration caused by bending small or negligible, thereby preventing cell fracture.

[0075] Exemplarily, the flexible conductive material includes metal foil. The material of the metal foil includes at least one of copper, aluminum, gold, silver, and tin. Preferably, the metal foil is copper foil or aluminum foil, or may be copper-aluminum composite metal foil.

[0076] For example, if both the second section 212 and the bent section 213 are made of metal foil, the metal foil has a large cross-sectional area, low resistance loss, and better adhesion to the busbar 32, thereby reducing the power loss of the photovoltaic module 10. The bent section 213 and the first section 211 can be connected using pressure-sensitive conductive tape or solder paste. The busbar 32 and the second section 212 can be connected using flux, solder paste, or pressure-sensitive conductive tape, with flux or solder paste being preferred.

[0077] In some embodiments, as Figure 2 As shown, the photovoltaic assembly 10 further includes a buffer layer 33 , which is disposed between the first segment 211 and the second segment 212 .

[0078] When the inner side of the bent section 213 is not adjacent to the side surface of the insulating strip 31 , the buffer layer 33 is still located between the inner side of the bent section 213 and the side surface of the insulating strip 31 .

[0079] The material of the buffer layer 33 may include insulating glue, or non-conductive tape or insulating film, such as polyethylene terephthalate or polyimide tape with acrylic or silicone, or polyethylene terephthalate or polyimide substrate with ethylene-vinyl acetate copolymer or hot melt adhesive coated on one side or both sides.

[0080] Combine Figure 2 As well as the bending process described above, considering the size and bending radius of the bending section 213 itself, a cavity may exist after bending, or in some embodiments, the height of the bending section 213 along the thickness direction Z will be higher than the height of the bus bar 32, and the first polarity welding strip 21 and the first battery cell 11 are in hard contact. During the lamination process, stress concentration can easily cause the battery cell to break, and it is more likely to cause breakage when subjected to external force.

[0081] In the embodiment of the present application, a buffer layer 33 is provided, and the above materials all have good elasticity, which can play a good buffering role. In some embodiments, it can also play a padding role, so that the height of the bending section 213 along the thickness direction Z is flush with the height of the bus bar 32, thereby improving the stress concentration problem and helping to improve the problem of battery cell fragmentation.

[0082] In some embodiments, as Figure 1As shown, the orthographic projection of the busbar 32 on the back surface P2 is within the range of the orthographic projection of the insulating strip 31 on the back surface P2. Based on this, the busbar 32 can be electrically isolated from the second polarity welding ribbon 22 and the second polarity auxiliary grid 102, so that the busbar 32 is electrically connected to the first polarity welding ribbon 21 only through the second section 212 and the bent section 213.

[0083] like Figure 2 As shown, along the second direction Y, the width L1 of the insulating strip 31 is greater than or equal to the width L2 of the bus bar 32. Exemplarily, the width L1 of the insulating strip 31 is greater than the width L2 of the bus bar 32 to reserve space for the alignment process of the bending operation, thereby ensuring that the boundary of the bus bar 32 does not exceed the boundary of the insulating strip 31, so that the bus bar 32 does not accidentally contact the second polarity welding ribbon 22.

[0084] In some embodiments, as Figure 1 As shown, the first cell 11 and the second cell 12 are arranged adjacent to each other along the second direction Y. Along the second direction Y, the end of the first polarity welding ribbon 21 is arranged at the edge of the first cell 11 close to the second cell 12. On the second cell 12, the end of the first polarity welding ribbon 21 close to the first cell 11 extends beyond the edge of the second cell 12 and is connected to the bus bar 32 on the first cell 11.

[0085] In some embodiments, as Figure 1 As shown, the first cell 11 and the second cell 12 are adjacently arranged along the first direction X. Along the first direction X, the bus bar 32 extends from the first cell 11 to the second cell 12 , and on the second cell 12 , the second polarity welding ribbon 22 is connected to the bus bar 32 .

[0086] Here, the bus bar 32 extends from the first battery cell 11 to the second battery cell 12. It can be understood that the bus bar 32 on the first battery cell 11 and the bus bar 32 on the second battery cell 12 are one continuous bus bar. It can also be understood that the bus bars 32 on the two battery cells are set separately and can be regarded as two separate structures, but the two are electrically connected together.

[0087] Expandable, such as Figure 5 As shown, Figure 5 A schematic structural diagram of another photovoltaic module provided in an embodiment of the present application.

[0088] The photovoltaic module 10 includes a first battery group C1 and a second battery group C2. Each battery group includes multiple battery cells connected in series. Taking the first battery group C1 as an example, multiple battery cells arranged along the second direction Y in each column constitute a battery string, and multiple columns arranged along the first direction X correspond to multiple battery strings in the first battery group C1. Figure 5A simplified diagram is provided in the figure, mainly used to illustrate the two battery cells at both ends of the battery string.

[0089] For the convenience of description and explanation, Figure 5 As shown, multiple battery cells are marked as battery cells 101 to battery cells 204 in sequence, where battery cells 101 and battery cells 102 correspond to the first battery string in the first battery group C1, and battery cells 201 and battery cells 202 correspond to the second battery string in the first battery group C1. Similarly, battery cells 103 and battery cells 104 correspond to the third battery string in the second battery group C2, and battery cells 203 and battery cells 204 correspond to the fourth battery string in the second battery group C2.

[0090] At the end of the first battery pack C1 facing away from the second battery pack C2, the first and second battery strings are connected in series. Cells 101 and 201 employ a design similar to that of the first cell described above. The difference is that on cell 101, busbar 32 is electrically connected to the first polarity ribbon 21, while on cell 201, busbar 32 is electrically connected to the second polarity ribbon 22. The same principle applies to the end of the second battery pack C2 facing away from the first battery pack C1, and will not be further described here.

[0091] In the part where the first battery group C1 and the second battery group C2 are close to each other, that is, the middle part of the photovoltaic module 10, the first battery string and the third battery string are connected in parallel, leading to one polarity end (for example, the negative pole) of the photovoltaic module 10, and the second battery string and the fourth battery string are connected in parallel, leading to the other polarity end (for example, the positive pole) of the photovoltaic module 10.

[0092] like Figure 5 As shown, in the photovoltaic module provided by this embodiment, the battery cells can be spliced ​​in short strings. In the final photovoltaic module, corresponding to one column of battery cells (which can be understood as a long string of photovoltaic modules), the hidden bus bar 32 can be located at the head or tail end of the long string, or at the middle part of the long string (that is, where two battery cells are spliced ​​together).

[0093] In some embodiments, as Figure 2 As shown, the bus bar 32 is located between the insulating bar 31 and the second segment 212. Alternatively, as shown in FIG. Figure 4 As shown, the bus bar 32 is located on a side of the second segment 212 away from the insulating strip 31 .

[0094] The relative position of the busbar 32 and the second section 212 is not limited and is independent of the material of the first polarity welding ribbon 21. Both the upper and lower surfaces of the busbar 32 include a tinned layer, allowing for soldering to the welding ribbon. This relative position can be adjusted based on the thickness of the insulating strip 31 and the height of the bent section 213 along the thickness direction Z, ensuring that the busbar 32 is parallel to the insulating strip 31, reducing stress concentration and improving the problem of cell fragmentation.

[0095] In a second aspect, the present application also provides a method for preparing a photovoltaic module, such as Figure 6 As shown, Figure 6 A flow chart of a method for preparing a photovoltaic module provided in an embodiment of the present application is provided. Figures 7 to 10 for Figure 6 Diagram of each step of the preparation method.

[0096] like Figure 6 As shown, the preparation method includes the following steps S01 to S05:

[0097] Step S01: Figure 7 As shown, a plurality of first polarity welding strips 21 and a plurality of second polarity welding strips 22 are provided on the back surface P2 of the first battery cell 11. Along a first direction X parallel to the back surface P2, the first polarity welding strips 21 and the second polarity welding strips 22 are alternately arranged. Along a second direction Y parallel to the back surface P2, one end of the first polarity welding strip 21 exceeds the edge of the first battery cell 11, and the second direction Y intersects with the first direction X.

[0098] It is understood that this is an example description based on the first polarity welding ribbon 21 corresponding to the first polarity grid line (for example, the positive grid line) and the second polarity welding ribbon 22 corresponding to the second polarity grid line (for example, the negative grid line), taking the battery cell used to achieve the first polarity electrical lead-out as an example. The first polarity welding ribbon 21 and the second polarity welding ribbon 22 are interchangeable. When the battery cell is used to achieve the second polarity electrical lead-out, one end of the second polarity welding ribbon 22 can be set to extend beyond the edge of the battery cell, and so on.

[0099] like Figure 7 As shown, the first polarity welding ribbon 21 extends out of the battery cell 11 by a length H1 , and this portion is used for subsequent connection with the bus bar 32 .

[0100] Step S02: Figure 8 As shown, an insulating strip 31 is provided on the back surface P2 of the first battery cell 11 , and the insulating strip 31 covers the ends of the plurality of first polarity welding strips 21 and the plurality of second polarity welding strips 22 . Along the second direction Y, the insulating strip 31 does not exceed the edge of the first battery cell 11 .

[0101] like Figure 8 As shown, along the second direction Y, the width of the insulating strip 31 is L1 , and there is a reference distance D1 between the edge of the insulating strip 31 and the edge of the first battery cell 11 , which reserves space for subsequent folding operations.

[0102] Step S03: Figure 9 As shown, the bus bar 32 is connected to the first polarity welding ribbon 21 , and the bus bar 32 is connected to the end of the first polarity welding ribbon 21 that exceeds the edge of the first battery cell 11 .

[0103] like Figure 9 As shown, the end of the first-polarity welding strip 21 includes a first segment 211, a second segment 212, and a bent segment 213. Here, the "end of the first-polarity welding strip 21 that extends beyond the edge of the first solar cell 11" can be correspondingly understood as the second segment 212. That is, the insulating strip 31 covers the first segment 211, the bus bar 32 is connected to the second segment 212, and the bent segment 213 is for bending.

[0104] Step S04: As Figure 10 shown, bend the end of the first-polarity welding strip 21 that extends beyond the edge of the first solar cell 11 so that the bus bar 32 is located on the side of the insulating strip 31 away from the first solar cell 11; along the second direction Y, the bent end of the first-polarity welding strip 21 does not extend beyond the edge of the first solar cell 11.

[0105] Combined with Figure 9 and Figure 10 , along the second direction Y, the width of the bus bar 32 is L2, and the width L2 of the bus bar 32 is less than or equal to the width L1 of the insulating strip 31. Preferably, L2 < L1, so as to reserve a certain margin for the bus bar 32 to be arranged on the insulating strip 31, ensuring that the edge of the bus bar 32 does not extend beyond the edge of the insulating strip 31 after the bending process is completed, avoiding the contact between the bus bar 32 and the non-connected welding strip, so as to ensure the corresponding insulation effect and avoid short circuits.

[0106] In some embodiments, along the second direction Y, the difference between the length H1 of the first-polarity welding strip 21 that extends beyond the edge of the first solar cell 11 and the width L2 of the bus bar 32 is greater than or equal to 2 mm, that is, H1 ≥ L2 + 2 mm.

[0107] As Figure 9 and Figure 10 shown, the reasonable difference margin reserves space for the welding of the bus bar 32 and the first-polarity welding strip 21, which can avoid the breakage of the solar cell during the welding process. Moreover, it can also reserve an operating space for the bending process, ensuring that the bent segment 213 will not cause a large stress concentration problem after the bending process is completed, which is beneficial to avoiding the problem of solar cell fragmentation.

[0108] Combined with Figure 9 and Figure 10 It can be understood that during the process of step S03 "connect the bus bar 32 to the first-polarity welding strip 21", the relative positional relationship between the bus bar 32 and the first-polarity welding strip 21 is not limited. Along the thickness direction Z, the bus bar 32 can be located on the first-polarity welding strip 21 or below the first-polarity welding strip 21.

[0109] The bus bar 32 and the first-polarity welding strip 21 can be connected by welding, and the welding method can be manual welding or stack welding.

[0110] Combined with Figure 5It can be understood that for the battery strings that need to be connected in series within a battery pack (the first battery pack C1 or the second battery pack C2), multiple battery strings can be placed along the first direction X first. Taking the series connection of battery cell 101 and battery cell 201 as an example, first, referring to step S01, one end of the first polarity welding strip 21 on the battery cell 101 extends beyond the edge of the battery cell 101, and one end of the second polarity welding strip 22 on the battery cell 201 extends beyond the edge of the battery cell 201.

[0111] Afterwards, referring to step S02, a full-length insulating strip 31 can be set so that the insulating strip 31 covers the ends of multiple first polarity welding strips 21 and multiple second polarity welding strips 22 on the battery cell 101, and covers the ends of multiple first polarity welding strips 21 and multiple second polarity welding strips 22 on the battery cell 201.

[0112] Next, referring to step S03 , a full-length bus bar 32 is provided so that the bus bar 32 is connected to the end of the first polarity welding ribbon 21 that exceeds the edge of the battery cell 101 and is connected to the end of the second polarity welding ribbon 22 that exceeds the edge of the battery cell 201 .

[0113] Then, referring to step S04 , the conductive structure extending beyond the edge of the cell is bent back into the cell through a bending process.

[0114] Step S05: Combination Figure 5 , connecting the second battery cell 12 to the bus bar 32 on the first battery cell 11.

[0115] For example, Figure 5 The middle cell 202 corresponds to the first cell 11 in the above step. After the end of the first polarity welding strip 21 on the cell 202 exceeds the edge of the cell and the bus bar 32 is bent back into the cell range, the cell 208 of the fourth cell string is placed on the side of the cell 202 close to the bus bar 32. The first polarity welding strip 21 on the cell 208 is extended beyond the edge of the cell 208 and electrically connected to the bus bar 32.

[0116] Based on the above method, multiple cells can be seamlessly spliced ​​together, thereby realizing the preparation of the photovoltaic module 10.

[0117] According to the preparation method provided in this application, combined with Figure 3 and Figure 8 As can be seen, the process of providing a continuous insulating strip 31 on the back of the cell is relatively simple and low-cost. No additional insulating glue needs to be printed on the second polarity sub-grid 102 covered by the insulating strip 31, which helps to reduce process steps and lower costs.

[0118] By first welding the busbar to the extended portion of the solder ribbon and then bending it behind the insulating strip, the busbar is concealed, simplifying the process. Bending the solder ribbon reduces thermal deformation during welding, improving the reliability and stability of the busbar-to-ribbon connection. Manual welding can be used to weld the busbar to the extended portion of the solder ribbon, replacing conventional stitch welding, further simplifying the process.

[0119] Furthermore, in some embodiments, the extended portion of the solder ribbon may include a metal foil. The metal foil is soft and easier to bend, which is beneficial for improving the reliability of the battery cell during the lamination process.

[0120] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that a person skilled in the art can conceive within the technical scope disclosed in this application should be included within the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A photovoltaic module, characterized in that: include: A plurality of battery cells, including a first battery cell and a second battery cell; the battery cells include opposite front and back surfaces; A plurality of first polarity welding strips and a plurality of second polarity welding strips are provided on the back surface of the battery cell; the first polarity welding strips and the second polarity welding strips are alternately arranged along a first direction parallel to the back surface; Insulation strips and bus bars are provided on the back side of the battery cell; Wherein, on the first battery cell, the end of the first polarity welding ribbon includes a first section, a second section, and a bent section, the first section is provided on the back side of the first battery cell, and the insulating strip covers the first sections of multiple first polarity welding ribbons and the ends of multiple second polarity welding ribbons; the bent section is connected to the first section, and the bent section is bent through the side of the insulating strip to the side of the insulating strip away from the first battery cell; the second section and the bus bar are both provided on the side of the insulating strip away from the first battery cell, the second section is connected to the bent section, and the bus bar is connected to the second section; Along a second direction parallel to the back surface, the insulating strip does not extend beyond the edge of the first battery cell, and the end of the first polarity welding strip does not extend beyond the edge of the first battery cell, and the second direction intersects the first direction; The second battery cell is connected to the bus bar on the first battery cell.

2. The photovoltaic module according to claim 1, characterized in that Along the second direction, a reference distance exists between a side surface of the insulating strip close to the bending section and an edge of the first battery cell.

3. The photovoltaic module according to claim 2, characterized in that The bent section contacts the side surface of the insulating strip, and along a direction perpendicular to the side surface of the insulating strip, a thickness of the bent section is less than or equal to the reference spacing.

4. The photovoltaic module according to claim 1, characterized in that Among the first segment, the second segment and the bent segment, at least the bent segment is made of a flexible conductive material.

5. The photovoltaic module according to claim 4, characterized in that: The flexible conductive material includes a metal foil.

6. The photovoltaic module according to claim 1, characterized in that The photovoltaic module further includes a buffer layer disposed between the first segment and the second segment.

7. The photovoltaic module according to claim 1, characterized in that The orthographic projection of the bus bar on the back surface is located within the range of the orthographic projection of the insulating strip on the back surface; Along the second direction, the width of the insulating strip is greater than or equal to the width of the bus bar.

8. The photovoltaic module according to claim 1, characterized in that Along the second direction, the first battery cell and the second battery cell are arranged adjacent to each other; Along the second direction, the end of the first polarity welding strip is arranged at an edge of the first battery cell close to the second battery cell; On the second battery cell, the end of the first polarity welding strip close to the first battery cell extends beyond the edge of the second battery cell and is connected to the bus bar on the first battery cell.

9. The photovoltaic module according to claim 1, characterized in that: Along the first direction, the first battery cell and the second battery cell are arranged adjacent to each other; Along the first direction, the bus bar extends from the first battery cell to the second battery cell; On the second battery cell, the second polarity welding ribbon is connected to the bus bar.

10. The photovoltaic module according to claim 1, characterized in that: The bus bar is located on a side of the second section away from the insulating strip; or, The bus bar is located between the insulating bar and the second segment.

11. A method for preparing a photovoltaic module, characterized in that: include: A plurality of first polarity welding ribbons and a plurality of second polarity welding ribbons are provided on the back surface of the first battery cell. The first polarity welding ribbons and the second polarity welding ribbons are alternately arranged along a first direction parallel to the back surface. One end of the first polarity welding ribbon extends beyond the edge of the first battery cell along a second direction parallel to the back surface, and the second direction intersects the first direction. An insulating strip is provided on the back surface of the first battery cell, the insulating strip covering ends of the plurality of first polarity welding strips and the plurality of second polarity welding strips; along the second direction, the insulating strip does not exceed the edge of the first battery cell; Connecting a bus bar to the first polarity welding ribbon, wherein the bus bar is connected to an end portion of the first polarity welding ribbon that exceeds an edge of the first battery cell; The end portion of the first polarity welding ribbon that exceeds the edge of the first battery cell is bent so that the bus bar is located on the side of the insulating strip away from the first battery cell; along the second direction, the bent end portion of the first polarity welding ribbon does not exceed the edge of the first battery cell; Connect the second battery cell to the bus bar on the first battery cell.

12. The preparation method according to claim 11, characterized in that Along the second direction, the difference between the length of the first polarity welding ribbon extending beyond the edge of the first battery cell and the width of the bus bar is greater than or equal to 2 mm.

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