Photovoltaic module, method of manufacturing and apparatus for manufacturing

Abstract

This application relates to the field of photovoltaic technology, providing a photovoltaic module, its fabrication method, and fabrication apparatus. The photovoltaic module includes: a cell string comprising multiple back contact cells, multiple first solder strips, multiple second solder strips, and multiple insulating strips. The multiple back contact cells are arranged sequentially along a first direction, and the first solder strips and second solder strips are alternately arranged along a second direction on one side of the back of the multiple back contact cells. The multiple insulating strips are located on the side of the multiple first solder strips away from the back contact cells. A busbar is located on the side of the multiple insulating strips away from the multiple first solder strips and intersects with the multiple first solder strips and the multiple second solder strips respectively. Multiple conductive portions have one end contacting the side surface of the busbar and the other end contacting the surface of the second solder strip. The side surface of the busbar is at least one of two opposing surfaces of the busbar along the second direction. The photovoltaic module provided by this application at least helps to solve the problems of high risk of microcracks and large loss of light-receiving area in the module.

Description

Technical Field

[0001] This application relates to the photovoltaic field, and in particular to a photovoltaic module, its preparation method and preparation apparatus. Background Technology

[0002] In current photovoltaic modules, the solder ribbons between the cells need to extend to the outside and make hard contact with the busbars, resulting in a 1.5-4mm non-light-receiving gap between the solder ribbons and the cells. This gap area cannot generate electricity, causing a loss of the effective light-receiving area of ​​the module, which in turn leads to power loss. Moreover, as the module size increases, the area of ​​loss and power loss increase simultaneously. At the same time, traditional welding methods rely on high-temperature hard-pressure contact, which can easily cause microcracks in the cells within the module. Summary of the Invention

[0003] This application provides a photovoltaic module, its preparation method, and preparation apparatus, which at least helps to solve the problems of high risk of microcracks and large loss of light-receiving area in existing photovoltaic modules.

[0004] According to some embodiments of this application, one aspect of this application provides a photovoltaic module, including: a battery string, comprising a plurality of back contact cells, a plurality of first solder strips, a plurality of second solder strips, and a plurality of insulating strips, wherein the plurality of back contact cells are arranged sequentially along a first direction, and the first solder strips and the second solder strips are alternately arranged along a second direction on one side of the back of the plurality of back contact cells, and the plurality of insulating strips are located on the side of the plurality of first solder strips away from the back contact cells, and the first direction intersects the second direction; a busbar, located on the side of the plurality of insulating strips away from the plurality of first solder strips, intersecting with the plurality of first solder strips and the plurality of second solder strips respectively; and a plurality of conductive portions, one end of the conductive portion contacting the side surface of the busbar, and the other end of the conductive portion contacting the surface of the second solder strip, wherein the side surface of the busbar is at least one of two surfaces of the busbar opposite each other along the first direction.

[0005] In some embodiments, the second solder strip is located between the busbar and the back contact battery, and the other end of the conductive portion contacts the surface of the second solder strip away from the back contact battery.

[0006] In some embodiments, one end of the conductive portion extends from the side of the busbar to the surface of the busbar away from the back contact battery, and the portion of the conductive portion on the surface of the busbar away from the back contact battery has a thickness of less than or equal to 50 μm in a third direction, which is perpendicular to the first direction and the second direction, respectively.

[0007] In some embodiments, the second solder strip is located on the side of the busbar away from the back contact battery, and the other end of the conductive portion contacts the surface of the second solder strip near the back contact battery.

[0008] In some embodiments, two adjacent back contact batteries located at non-head and tail positions along the first direction in the battery string are respectively a first battery cell and a second battery cell, and the busbar is located on the second battery cell; the first battery cell and the second battery cell are connected in series by the second solder strip; the first solder strip on the first battery cell and the first solder strip on the second battery cell are aligned in the first direction and have a gap.

[0009] In some embodiments, two adjacent back contact batteries located at non-head and tail positions along the first direction in the battery string are respectively a first battery cell and a second battery cell, and the busbar is located on the second battery cell; the first battery cell and the second battery cell are connected in series by the second solder strip; the first solder strip on the first battery cell has an extension extending to the second battery cell, and the extension is offset from the first solder strip on the second battery cell in the first direction and overlaps with it in the second direction.

[0010] In some embodiments, the extension overlaps with the insulating strip, and the third direction is perpendicular to the first direction and the second direction, respectively.

[0011] In some embodiments, in the battery string, any two adjacent back-contact batteries satisfy at least one of the following: having a gap, being adjacent, or partially overlapping in a third direction, wherein the third direction is perpendicular to the first direction and the second direction, respectively.

[0012] In some embodiments, the width of the insulating strip in the second direction is greater than or equal to 1.5 times the width of the first solder strip in the second direction, and less than or equal to 3 / 4 of the distance between the first solder strip and the second solder strip.

[0013] In some embodiments, the width of the conductive portion in the first direction is 1-2 mm, and the width of the conductive portion in the second direction is 2-8 mm.

[0014] In some embodiments, the photovoltaic module includes multiple battery string groups and multiple busbars. Each battery string group includes two battery strings arranged along the second direction. In each battery string, the back contact cells located at the beginning and end along the first direction are end cells, and the back contact cells located in the middle along the first direction are middle cells. The multiple busbars include end busbars and middle busbars. The two ends of the end busbars are respectively located on the back side of the two end cells in the battery string group, and the two ends of the middle busbars are respectively located on the back side of the adjacent middle cells in the two battery string groups.

[0015] According to some embodiments of this application, another aspect of this application provides a method for manufacturing a photovoltaic module, for manufacturing any of the photovoltaic modules described above, comprising: providing a battery string, the battery string including a plurality of back contact cells, a plurality of first solder strips, a plurality of second solder strips, and a plurality of insulating strips, the plurality of back contact cells being arranged sequentially along a first direction, the first solder strips and the second solder strips being alternately arranged along a second direction on one side of the back of the plurality of back contact cells, the plurality of insulating strips being located on the side of the plurality of first solder strips away from the back contact cells, the first direction intersecting the second direction; providing a busbar on the side of the plurality of insulating strips away from the plurality of first solder strips, the busbar intersecting the plurality of first solder strips and the plurality of second solder strips respectively; forming a plurality of conductive portions with one end contacting the side surface of the busbar and the other end contacting the second solder strip, the side surface of the busbar being at least one of two surfaces of the busbar opposite each other along the first direction.

[0016] In some embodiments, forming a plurality of conductive portions, one end of which contacts the side of the busbar and the other end of which contacts the surface of the second solder strip, includes: heating an alloy material to a molten state; non-contactly coating the molten alloy material at the intersection of the busbar and the second solder strip, such that the alloy material contacts both the side of the busbar and the surface of the second solder strip, forming a plurality of preliminary conductive portions; and cooling the plurality of preliminary conductive portions to solidify them, thereby obtaining the conductive portions.

[0017] According to some embodiments of this application, another aspect of this application provides a photovoltaic module fabrication apparatus for fabricating any of the photovoltaic modules described above, comprising: a fabrication unit for fabricating a battery string, the battery string including a plurality of back contact cells, a plurality of first solder strips, a plurality of second solder strips, and a plurality of insulating strips, the plurality of back contact cells being arranged sequentially along a first direction, the first solder strips and the second solder strips being alternately arranged along a second direction on one side of the back of the plurality of back contact cells, the plurality of insulating strips being located on the side of the plurality of first solder strips away from the back contact cells, the first direction intersecting the second direction; a setting unit for setting a busbar on the side of the plurality of insulating strips away from the plurality of first solder strips, the busbar intersecting with the plurality of first solder strips and the plurality of second solder strips respectively; and a drip welding unit for forming a plurality of conductive portions with one end contacting the side surface of the busbar and the other end contacting the surface of the second solder strip, the side surface of the busbar being at least one of two surfaces of the busbar opposite each other along the first direction.

[0018] The technical solution provided in this application has at least the following advantages:

[0019] The photovoltaic module of this application achieves a piezoelectric connection between the busbar and the second solder strip by having one end of the conductive part contact the busbar and the other end contact the second solder strip. This avoids welding the busbar and the solder strip through hot pressing or mechanical pressure, fundamentally eliminating the path of welding stress transmission to the cell, significantly reducing the risk of microcracks in the cell caused by thermal or mechanical stress, and improving the structural reliability and long-term operational stability of the module. At the same time, the insulating strip is placed between the busbar and the first solder strip, physically isolating the electrical contact between the busbar and the first solder strip, allowing the busbar to be placed on the back of the back contact cell. This avoids the problem of the busbar and the back contact cell occupying the module area when placed on the same layer, thus affecting the effective light-receiving area of ​​the cell. Attached Figure Description

[0020] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the drawings in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a top view of the structure of the first photovoltaic module provided in one embodiment of this application;

[0022] Figure 2This is a top view of the structure of a second type of photovoltaic module provided in one embodiment of this application;

[0023] Figure 3 This is a top view of the third type of photovoltaic module provided in one embodiment of this application;

[0024] Figure 4 This is a top view of the fourth type of photovoltaic module provided in one embodiment of this application;

[0025] Figure 5 This is a top view of the fifth type of photovoltaic module provided in one embodiment of this application;

[0026] Figure 6 This is a top view of the sixth type of photovoltaic module provided in one embodiment of this application;

[0027] Figure 7 This is a schematic cross-sectional view of a photovoltaic module provided in one embodiment of this application;

[0028] Figure 8 This is a flowchart illustrating a method for manufacturing a photovoltaic module according to one embodiment of this application;

[0029] Figure 9 This is a structural block diagram of a photovoltaic module fabrication apparatus provided in one embodiment of this application.

[0030] The above figures include the following reference numerals:

[0031] 10. Battery string; 11. Back contact battery; 12. First solder strip; 13. Second solder strip; 14. Insulating strip; 15. Busbar; 16. Conductive part; 17. First battery cell; 18. Second battery cell; 19. Extension part; 20. Battery string assembly; 21. End battery cell; 22. Middle battery cell; 23. End busbar; 24. Middle busbar; 25. Encapsulating film; 26. Cover plate; 30. Fabrication unit; 31. Setting unit; 32. Drop welding unit. Detailed Implementation

[0032] As the background technology shows, the traditional welding method for solder strips and busbars not only affects the effective light-receiving area of ​​the module, but also increases the risk of microcracks in the cells. These problems have hindered further improvements in module yield.

[0033] Based on the aforementioned technical problems, this application provides a photovoltaic module, its fabrication method, and fabrication apparatus. In the photovoltaic module, a busbar is disposed on the back of the solar cell. A conductive part contacts the busbar and a second solder strip (with the same polarity as the busbar) to achieve electrical connection between the two. At the same time, an insulating strip is used to achieve physical isolation between the busbar and the first solder strip (with the opposite polarity to the busbar). This avoids the ineffective gap between the solder strip and the busbar caused by the busbar being disposed on the same layer as the back contact cell, maximizes the effective light-receiving area, and achieves pressureless welding, significantly reducing the risk of microcracks in the solar cell.

[0034] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0035] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0036] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after are in an "or" relationship.

[0037] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0038] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0039] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0040] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0041] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Moreover, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0042] The terminology used in the description of the various embodiments described herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "foreword" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0043] The following will be combined with the appendix Figures 1 to 9 The various embodiments of this application are described in detail. However, those skilled in the art will understand that many technical details have been presented in the various embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0044] One embodiment of this application provides a photovoltaic module, such as... Figure 1 As shown, the photovoltaic module mentioned above includes:

[0045] The battery string 10 includes a plurality of back contact batteries 11, a plurality of first solder strips 12, a plurality of second solder strips 13, and a plurality of insulating strips 14. The plurality of back contact batteries 11 are arranged sequentially along a first direction. The first solder strips 12 and the second solder strips 13 are arranged alternately along a second direction on one side of the back of the plurality of back contact batteries 11. The plurality of insulating strips 14 are located on the side of the plurality of first solder strips 12 away from the back contact batteries 11. The first direction intersects the second direction.

[0046] The back contact battery 11 in this application is typically a sheet-like structure. The side that absorbs light energy and converts it into electrical energy is called the light-facing side or front side of the back contact battery 11, and the other side is called the back-facing side or back side of the back contact battery 11. Each back contact battery 11 includes positive and negative grid lines located on the back side. It is understood that the positive grid line can be defined as a grid line for collecting positive charge carriers, and the negative grid line can be defined as a grid line for collecting negative charge carriers. The first solder strip 12 and the second solder strip 13 are used to electrically connect adjacent back contact batteries 11 in the battery string 10. Specifically, they are used to electrically connect grid lines of different polarities in the back contact batteries 11. Optionally, the first direction and the second direction can be perpendicular to each other. It is understood that the plurality of insulating strips 14 located on the side of the plurality of first solder strips 12 away from the back contact batteries 11 means that the projection of the insulating strip 14 on the back contact battery 11 overlaps with the projection of the first solder strip 12 on the back contact battery 11.

[0047] Busbar 15 is located on the side of the plurality of insulating strips 14 away from the plurality of first solder strips 12, and intersects with the plurality of first solder strips 12 and the plurality of second solder strips 13 respectively;

[0048] Optionally, the busbar 15 may extend along the second direction to intersect with the plurality of first solder strips 12 and the plurality of second solder strips 13. In this application, the insulating strip 14 is located in the intersection area of ​​the busbar 15 and the first solder strips 12, thereby achieving electrical insulation between the busbar 15 and the first solder strips 12. The busbar 15 is used to collect current from the battery string and lead the current to the module junction box.

[0049] Multiple conductive parts 16, one end of the conductive part 16 contacts the side of the busbar 15, and the other end of the conductive part 16 contacts the surface of the second solder strip 13. The side of the busbar 15 is at least one of the two surfaces of the busbar 15 that are opposite each other along the first direction.

[0050] Specifically, one end of the conductive part 16 contacts the busbar 15, and the other end contacts the second solder strip 13, thereby achieving an electrical connection between the busbar 15 and the conductive part 16.

[0051] In the above embodiments, by having one end of the conductive part contact the busbar and the other end contact the second solder strip, a piezoelectric connection between the busbar and the second solder strip is achieved. This avoids welding the busbar and solder strip through hot pressing or mechanical pressure, fundamentally eliminating the path of welding stress transmission to the solar cell. This significantly reduces the risk of microcracks in the solar cell caused by thermal or mechanical stress, and improves the structural reliability and long-term operational stability of the module. At the same time, by placing an insulating strip between the busbar and the first solder strip, the electrical contact between the busbar and the first solder strip is physically isolated. This allows the busbar to be placed on the back side of the back contact cell, avoiding the problem of the busbar and the back contact cell occupying module area when placed on the same layer, thus affecting the effective light-receiving area of ​​the solar cell.

[0052] Specifically, this application provides an insulating strip on the surface of the first solder strip to physically isolate it from direct electrical contact with the busbar, allowing only the second solder strip to form an electrical connection with the busbar through the conductive part. This achieves precise electrode polarity control and current path guidance without the need for additional isolation circuits, effectively preventing inter-series short circuits and improving the electrical reliability of the component.

[0053] The back contact cell 11 of this application can be made of semiconductor materials, such as a P-type silicon wafer, which forms a PN junction after phosphorus diffusion; or an N-type silicon wafer, which forms a PN junction after boron diffusion. When the back contact cell 11 uses an N-type silicon wafer, the doping element of the N-type silicon wafer may include antimony. When the back contact cell 11 uses a P-type silicon wafer, the doping element of the P-type silicon wafer may include boron.

[0054] Optionally, the first solder strip 12 and the second solder strip 13 can be flat strips, round strips, or strips with irregular cross-sections (such as trapezoidal, U-shaped, etc.). Optionally, the materials of the first solder strip 12 and the second solder strip 13 can be tin-plated copper strips, lead-free alloy strips, or copper-clad aluminum composite strips, taking into account conductivity, corrosion resistance, and cost control.

[0055] The first solder strip 12 and the second solder strip 13 described in this application can be planar solder strips (i.e., the surfaces of the solder strips near and away from the back contact battery 11 are planar) or irregularly shaped solder strips (i.e., the surfaces of the solder strips near and / or away from the back contact battery 11 are not planar). In some other embodiments, the first solder strip 12 and the second solder strip 13 can be solder strip structures with a thickness (i.e., the thickness value in the third direction) that varies gradient along a first direction and / or a second direction.

[0056] The insulating strip 14 described in this application can be a planar insulating strip (i.e., the surfaces of the insulating strip 14 near and away from the back contact battery 11 are planar) or an irregularly shaped insulating strip (i.e., the surfaces of the insulating strip 14 near and / or away from the back contact battery 11 are not planar). In some other embodiments, the insulating strip 14 can be an insulating strip structure with a thickness (i.e., the thickness value in the third direction) that varies gradient along a first direction and / or a second direction.

[0057] It is understood that the gradient change described above in this application can be either first increasing and then decreasing (i.e., the thickness of the middle part is greater than the thickness of the two ends) or first decreasing and then increasing (i.e., the thickness of the middle part is less than the thickness of the two ends).

[0058] Optionally, the busbar 15 can be a single-layer, double-layer, or folded structure. The busbar 15 can be a metal conductor such as copper foil, tin-plated copper strip, or aluminum foil, or it can adopt other single or composite conductive structures, such as a composite structure of flexible copper foil and hot melt adhesive film.

[0059] According to some alternative solutions of this application, such as Figure 1 As shown, the second solder strip 13 is located between the busbar 15 and the back contact battery 11. One end of the conductive portion 16 contacts the side of the busbar 15, and the other end of the conductive portion 16 contacts the surface of the second solder strip 13 away from the back contact battery 11. In this embodiment, by placing the second solder strip between the busbar and the back contact battery, and making the other end of the conductive portion contact the surface of the second solder strip away from the back contact battery, a stable and direct conductive connection between the busbar and the second solder strip is achieved, further reducing the risk of microcracks in the battery cells caused by traditional welding and improving the reliability of the electrical connection.

[0060] According to some specific implementations of this application, one end of the conductive portion 16 extends from the side of the busbar 15 to the surface of the busbar 15 away from the back contact battery 11. The thickness of the portion of the conductive portion 16 on the surface of the busbar 15 away from the back contact battery 11 in a third direction is less than or equal to 50 μm, and the third direction is perpendicular to the first direction and the second direction, respectively. One end of the conductive portion extends from the side of the busbar to its upper surface away from the back contact battery, and the thickness of this portion in a third direction is limited to less than or equal to 50 μm. By controlling the thickness of the conductive portion in the top region of the busbar to be small, the overall height of the busbar tends to be flatter. This design effectively avoids uneven thickness and stress concentration caused by local material accumulation during the lamination process due to local bulges in the busbar, thereby further improving the component yield. Furthermore, by controlling the thickness of the conductive portion in the top region of the busbar to be less than or equal to 50 μm, the amount of conductive portion used can be reduced while ensuring a stable, low-resistance electrical connection, thereby reducing material costs. In addition, the thin-layer structure has higher thermal conductivity, which is conducive to rapid heat dissipation after the conductive part is formed, and helps to reduce the risk of thermal damage to the battery cell or busbar due to local heat accumulation.

[0061] It is understood that the thickness of the conductive portion 16 located on the surface of the busbar 15 away from the back contact battery 11 in the third direction is greater than or equal to 0.

[0062] In some other alternatives to this application, such as Figure 2 As shown, the second solder strip 13 is located on the side of the busbar 15 away from the back contact battery 11. One end of the conductive portion 16 contacts the side of the busbar 15, and the other end of the conductive portion 16 contacts the surface of the second solder strip 13 near the back contact battery 11. In this embodiment, by placing the second solder strip on the side of the busbar away from the back contact battery, and by having one end of the conductive portion contact the side of the busbar 15 and the other end contact the surface of the second solder strip near the back contact battery, a stable conductive path is formed between the busbar and the second solder strip. This allows the conductive portion to reliably connect the side of the busbar and the surface of the second solder strip away from the battery, thereby achieving a reliable electrical connection between the busbar and the second solder strip.

[0063] In some exemplary embodiments, such as Figure 3 and Figure 4As shown, in the battery string 10, the two adjacent back-contact batteries 11 located at non-head and tail positions along the first direction are respectively the first battery cell 17 and the second battery cell 18, and the busbar 15 is located on the second battery cell 18; the first battery cell 17 and the second battery cell 18 are connected in series by the second solder ribbon 13, in other words, the second solder ribbon 13 extends from the back of the first battery cell 17 to the back of the second battery cell 18, thereby realizing the series connection between the two; the first solder ribbon 12 on the first battery cell 17 and the first solder ribbon 12 on the second battery cell 18 are aligned and spaced apart in the first direction, that is, along the first direction, the first solder ribbon 12 on the first battery cell 17 overlaps with the first solder ribbon 12 on the second battery cell 18, and along the second direction, the first solder ribbon 12 on the first battery cell 17 and the first solder ribbon 12 on the second battery cell 18 do not overlap. In the above embodiments, the series connection between the first battery cell and the second battery cell is achieved by the second solder strip; at the same time, the first solder strip on the first battery cell and the first solder strip on the second battery cell are staggered in the second direction to avoid battery short circuit problems.

[0064] According to another embodiment of this application, such as Figure 5 As shown, in the battery string 10, the two adjacent back-contact batteries 11 located at non-end-end positions along the first direction are respectively the first battery cell 17 and the second battery cell 18, and the busbar 15 is located on the second battery cell 18; the first battery cell 17 and the second battery cell 18 are connected in series by the second solder ribbon 13. In other words, the second solder ribbon 13 extends from the back of the first battery cell 17 to the back of the second battery cell 18, thereby realizing the series connection between the two; the first solder ribbon 12 on the first battery cell 17 has an extension 19 extending to the second battery cell 18. The extension 19 and the first solder ribbon 12 on the second battery cell 18 are staggered in the first direction and overlap in the second direction. That is, along the first direction, the extension 19 and the first solder ribbon 12 on the second battery cell 18 do not overlap, and along the second direction, the extension 19 and the first solder ribbon 12 on the second battery cell 18 overlap.

[0065] In the above embodiments, the first battery cell and the second battery cell are connected in series by the second solder strip; at the same time, by setting the first solder strip on the first battery cell to extend to the second battery cell, and setting the extension to be staggered from the first solder strip on the second battery cell in a first direction, the short circuit problem between adjacent battery cells is further avoided.

[0066] Optionally, such as Figure 5As shown, in the third direction, the extension 19 overlaps with the insulating strip 14, and the third direction is perpendicular to the first direction and the second direction, respectively. By making the extension overlap with the insulating strip in the third direction, it is ensured that at least part of the extension is stably covered by the insulating strip, further preventing short circuits or polarity misconnections caused by electrical contact between the extension and the solder strip or busbar on the second battery cell, and further achieving reliable isolation of the internal current path of the battery string.

[0067] like Figure 5 As shown, in the third direction, the insulating strip 14 overlaps at least with the end of the extension 19.

[0068] In some alternative embodiments, in the aforementioned third direction, the extension portion 19 can be offset from the busbar 15 and the insulating strip 14, respectively. This embodiment, by setting the extension portion offset from the insulating strip and the busbar, further prevents short circuits or incorrect polarity connections caused by electrical contact between the extension portion and the solder strip or busbar on the second battery cell, and further achieves reliable isolation of the internal current path of the battery string.

[0069] Specifically, the aforementioned extension 19 refers to the portion of the first solder strip 12 located on the second battery cell 18.

[0070] It should be noted that the overlapping of two structures along one direction mentioned above in this application can refer to one of the following: along this direction, a part of one structure overlaps with a part of another structure; along this direction, one structure covers another structure.

[0071] In some embodiments, in the battery string 10 described above, any two adjacent back contact batteries 11 satisfy at least one of the following: Figure 3 The diagram shows two back-contact batteries 11 arranged at intervals in the first direction; as shown... Figure 4 and Figure 5 The adjacent arrangement shown refers to the edge contact of two back contact batteries 11 with no overlap in a third direction; the partial overlap in a third direction is perpendicular to the first and second directions, respectively, meaning at least a portion of the edges of the two back contact batteries 11 overlap. By arranging any two adjacent back contact batteries in the battery string to satisfy at least one of the following arrangements: "having a gap, being adjacent, or partially overlapping in a third direction", flexibility in the component structure design is achieved.

[0072] According to some alternative embodiments of this application, the width of the insulating strip 14 in the second direction is greater than or equal to 1.5 times the width of the first solder strip 12 in the second direction, and less than or equal to 3 / 4 of the distance between the first solder strip 12 and the second solder strip 13. By limiting the width of the insulating strip in the second direction to be greater than or equal to 1.5 times the width of the first solder strip in the second direction and less than or equal to 3 / 4 of the distance between the first solder strip and the second solder strip, it is ensured that the insulating strip can fully shield the first solder strip in the third direction and form a reliable electrical isolation area, avoiding unintended conduction between the busbar and the first solder strip due to insufficient shielding, while preventing the insulating strip from excessively extending and intruding into the area where the second solder strip is located, ensuring stable contact between the conductive part and the surface of the second solder strip.

[0073] For example, the width of the conductive portion 16 in the first direction is 1mm to 2mm. For instance, the width of the conductive portion 16 in the first direction can be 1mm, 1.2mm, 1.4mm, 1.5mm, 1.6mm, 1.8mm, 2mm, or any other value within the range of 1mm to 2mm. The width of the conductive portion 16 in the second direction is 2mm to 8mm. For instance, the width of the conductive portion 16 in the second direction can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, or any other value within the range of 2mm to 8mm. By limiting the width of the conductive part to 1~2mm in the first direction and 2~8mm in the second direction, and combining the structural design of one end of the conductive part contacting the side of the busbar and the other end contacting the surface of the second solder strip, the conductive part can achieve a stable electrical connection between the busbar and the second solder strip while effectively controlling its lateral and longitudinal dimensional range. This avoids problems such as redundant welding area, material waste and thermal stress concentration due to excessive size, or insufficient contact area, increased contact resistance and abnormal current density due to insufficient size.

[0074] For example, the shape of the conductive part 16 may include, but is not limited to, a sphere, an ellipsoid, a hemisphere, a cube, or other regular or irregular shapes.

[0075] In one alternative embodiment, such as Figure 6As shown, the photovoltaic module includes multiple battery string groups 20 and multiple busbars 15. Each battery string group 20 includes two battery strings 10 arranged along the second direction. In each battery string 10, the back contact cells 11 located at the beginning and end along the first direction are end cells 21, and the back contact cells 11 located in the middle along the first direction are middle cells 22. The multiple busbars 15 include end busbars 23 and middle busbars 24. The two ends of the end busbars 23 are respectively located on the back side of the two end cells 21 in the battery string group 20, that is, the end busbars 23 are electrically connected to the two end cells 21 in the battery string group 20. The two ends of the middle busbars 24 are respectively located on the back side of the adjacent middle cells 22 in the two battery string groups 20, that is, the middle busbars 24 are electrically connected to the adjacent middle cells 22 in the two battery string groups 20. In this embodiment, the series connection between battery strings within the battery string group is achieved through the end busbar, and the series connection between adjacent battery string groups is achieved through the middle busbar, thereby realizing the parallel connection between battery strings on both sides of the middle busbar in the battery string group.

[0076] It is understood that the aforementioned intermediate position can refer to any position other than the ends of the battery string. In other words, the aforementioned intermediate battery cell can be any back contact battery in the battery string other than the end battery cells. In one embodiment, the aforementioned intermediate battery cell can be a back contact battery located at the median position in the battery string. That is, when the battery string includes n (even) back contact batteries, the aforementioned intermediate battery cell can be the n / 2th or n / 2+1th back contact battery along the first direction X; when the battery string includes m (odd) back contact batteries, the aforementioned intermediate battery cell can be the (m+1) / 2th back contact battery along the first direction X.

[0077] In practical applications, the number and position of the first solder strip, the second solder strip, and the busbar in a photovoltaic module can be designed according to requirements. The number and position of the first solder strip and the second solder strip can be set according to the number and arrangement of the grid lines on each back contact cell, and the number and position of the busbar can be set according to the current transmission capacity requirements of the photovoltaic module. In this embodiment, the number and position of the first solder strip, the second solder strip, and the busbar in the photovoltaic module are not limited.

[0078] In some embodiments, the busbars contact each of the second solder strips via one or two of the conductive portions.

[0079] In other embodiments, the height of the conductive portion in the third direction is greater than or equal to 2 / 3 of the height of the busbar in the third direction, and less than or equal to the height of the busbar in the third direction.

[0080] In other embodiments, the conductive portion may also cover at least a portion of the busbar surface away from the back contact battery. That is, the height of the conductive portion in the third direction may be appropriately greater than the height of the busbar in the third direction.

[0081] Figure 7 This is a schematic cross-sectional view of a photovoltaic module according to an embodiment of this application, as shown below. Figure 7 As shown, in some embodiments, the photovoltaic module further includes an encapsulating film 25 and a cover plate 26.

[0082] The encapsulating film 25 is used to cover the surface of the battery string 10, isolating the back contact cells in the battery string 10 from the external environment, preventing water vapor and oxygen from corroding the back contact cells, thereby improving the reliability of the photovoltaic module and extending its service life. The encapsulating film 25 can be made of, but is not limited to, ethylene-vinyl acetate copolymer (EVA) film, polyolefin elastomer (POE) film, etc.

[0083] The cover plate 26 is used to cover the surface of the encapsulating film 25 away from the cell string 10. It can be used to protect the internal structure of the photovoltaic module and improve the reliability of the photovoltaic module. The cover plate 26 can be made of materials with high hardness and good light transmittance, such as glass, so as to provide protection for the photovoltaic module while allowing as much light as possible to enter the back contact cell for utilization.

[0084] Another aspect of this application provides a method for preparing a photovoltaic module, used to prepare any of the above-mentioned photovoltaic modules, such as... Figure 8 As shown, the method for preparing the above-mentioned photovoltaic module includes:

[0085] Step S201: Provide a battery string, the battery string including multiple back contact batteries, multiple first solder strips, multiple second solder strips and multiple insulating strips, the multiple back contact batteries are arranged sequentially along a first direction, the first solder strips and the second solder strips are alternately arranged along a second direction on one side of the back of the multiple back contact batteries, the multiple insulating strips are located on the side of the multiple first solder strips away from the back contact batteries, the first direction intersects the second direction;

[0086] Optionally, the first direction and the second direction can be perpendicular to each other.

[0087] Step S202: A busbar is provided on the side of the plurality of insulating strips away from the plurality of first solder strips, and the busbar intersects with the plurality of first solder strips and the plurality of second solder strips respectively;

[0088] Optionally, the aforementioned busbar can extend along the aforementioned second direction to intersect with the plurality of aforementioned first weld strips and the plurality of aforementioned second weld strips.

[0089] Step S203: A plurality of conductive portions are formed, one end of which contacts the side of the busbar and the other end of which contacts the surface of the second solder strip. The side of the busbar is at least one of the two surfaces of the busbar that are opposite each other along the first direction.

[0090] Specifically, one end of the conductive part contacts the busbar and the other end contacts the second solder strip, thereby achieving an electrical connection between the busbar and the conductive part.

[0091] The above embodiments first provide a battery string comprising multiple back contact cells, multiple first solder strips, multiple second solder strips, and multiple insulating strips. Next, a busbar is positioned on the side of the multiple insulating strips away from the multiple first solder strips, such that the busbar intersects with both the multiple first solder strips and the multiple second solder strips. Finally, multiple conductive portions are formed, one end contacting the side of the busbar and the other end contacting the surface of the second solder strips. By having one end of the conductive portion contact the busbar and the other end contact the second solder strip, a piezoelectric connection between the busbar and the second solder strip is achieved. This avoids welding the busbar and solder strips using hot pressing or mechanical pressure, fundamentally eliminating the path of welding stress transmission to the battery cells. This significantly reduces the risk of microcracks in the battery cells caused by thermal or mechanical stress, improving the structural reliability and long-term operational stability of the module. Simultaneously, placing the insulating strip between the busbar and the first solder strips physically isolates the electrical contact between them, allowing the busbar to be positioned on the back side of the back contact cells. This avoids the problem of the busbar and back contact cells occupying module area and thus affecting the effective light-receiving area of ​​the battery cells.

[0092] In some embodiments, forming a plurality of conductive portions, one end of which contacts the side of the busbar and the other end of which contacts the surface of the second solder strip, includes: heating an alloy material to a molten state; non-contactly coating the molten alloy material onto the intersection of the busbar and the second solder strip, such that the alloy material contacts both the side of the busbar and the surface of the second solder strip, forming a plurality of preliminary conductive portions; and cooling the plurality of preliminary conductive portions to solidify them, thereby obtaining the conductive portion. This application forms preliminary conductive portions for electrically connecting the busbar and the second solder strip through a non-contact coating method, and then cools and shapes them to obtain the conductive portion. This further achieves the welding effect between the busbar and the second solder strip, and further avoids problems such as microcracks in the battery cells caused by traditional hard-press welding processes.

[0093] Compared to the traditional hard pressing method, the method of forming a conductive part by drip welding to achieve the welding effect between the busbar and the second welding strip only requires attaching the busbar and the second welding strip together and dripping the hot-melt conductive alloy material onto the joint between the two. Therefore, the implementation method and the equipment used are simpler and more convenient.

[0094] For example, non-contactly coating the molten alloy material at the intersection of the busbar and the second welding strip may include: using a drop welding device to drop the molten alloy material onto the intersection of the busbar and the second welding strip.

[0095] Optionally, cooling the plurality of the above-mentioned pre-conductive parts may include cooling the plurality of the above-mentioned pre-conductive parts by means of air cooling or other cooling methods.

[0096] In another aspect, this application also provides a photovoltaic module fabrication apparatus for fabricating any of the above-described photovoltaic modules, such as... Figure 9 As shown, the apparatus for manufacturing the photovoltaic module includes:

[0097] The preparation unit 30 is used to prepare a battery string, which includes multiple back contact batteries, multiple first solder strips, multiple second solder strips and multiple insulating strips. The multiple back contact batteries are arranged sequentially along a first direction. The first solder strips and the second solder strips are alternately arranged on one side of the back of the multiple back contact batteries along a second direction. The multiple insulating strips are located on the side of the multiple first solder strips away from the back contact batteries. The first direction intersects with the second direction.

[0098] Optionally, the first direction and the second direction can be perpendicular to each other.

[0099] Setting unit 31 is used to set a busbar on the side of the plurality of insulating strips away from the plurality of first welding strips, wherein the busbar intersects with the plurality of first welding strips and the plurality of second welding strips respectively;

[0100] Optionally, the aforementioned busbar can extend along the aforementioned second direction to intersect with the plurality of aforementioned first weld strips and the plurality of aforementioned second weld strips.

[0101] The drop welding unit 32 is used to form a plurality of conductive portions on the surface of the busbar with one end in contact with the side of the busbar and the other end in contact with the second welding strip, wherein the side of the busbar is at least one of two surfaces of the busbar that are opposite each other along the first direction.

[0102] Specifically, one end of the conductive part contacts the busbar and the other end contacts the second solder strip, thereby achieving an electrical connection between the busbar and the conductive part.

[0103] In the above embodiments, a battery string including multiple back contact batteries, multiple first solder strips, multiple second solder strips, and multiple insulating strips is prepared by the preparation unit; a busbar is set on the side of the multiple insulating strips away from the multiple first solder strips by the setting unit, so that the busbar intersects with the multiple first solder strips and the multiple second solder strips respectively; and multiple conductive parts with one end in contact with the side of the busbar and the other end in contact with the surface of the second solder strip are formed by the drop welding unit. By having one end of the conductive part contact the busbar and the other end contact the second solder strip, a piezoelectric connection between the busbar and the second solder strip is achieved. This avoids welding the busbar and solder strip through hot pressing or mechanical pressure, fundamentally eliminating the path of welding stress transmission to the solar cell. This significantly reduces the risk of microcracks in the solar cell caused by thermal or mechanical stress, and improves the structural reliability and long-term operational stability of the module. At the same time, placing the insulating strip between the busbar and the first solder strip physically isolates the electrical contact between the busbar and the first solder strip, allowing the busbar to be placed on the back side of the back contact cell. This avoids the problem of the busbar and the back contact cell occupying module area when placed on the same layer, thus affecting the effective light-receiving area of ​​the solar cell.

[0104] In some embodiments, the aforementioned drip welding unit includes: a heating module for heating the alloy material to a molten state; a coating module for non-contactly coating the molten alloy material onto the intersection of the busbar and the second welding strip, such that the alloy material contacts the side of the busbar and the surface of the second welding strip respectively, forming a plurality of pre-conductive portions; and a cooling module for cooling the plurality of pre-conductive portions, causing them to solidify to obtain the conductive portion. This application forms pre-conductive portions for electrically connecting the busbar and the second welding strip through a non-contact coating method, and then cools and shapes them to obtain the conductive portion. This further achieves the welding effect between the busbar and the second welding strip, and further avoids problems such as microcracks in the battery cells caused by traditional hard-press welding processes.

[0105] Compared to the traditional hard pressing method, the method of forming a conductive part by drip welding to achieve the welding effect between the busbar and the second welding strip only requires attaching the busbar and the second welding strip together and dripping the hot-melt conductive alloy material onto the joint between the two. Therefore, the implementation method and the equipment used are simpler and more convenient.

[0106] For example, the coating module may include a drip welding submodule, used to drip the molten alloy material onto the position where the busbar intersects with the second welding strip using a drip welding device.

[0107] Optionally, the cooling module may include an air-cooling submodule for cooling multiple of the aforementioned pre-conductive parts using air cooling or other cooling methods.

[0108] In this field, since the connecting material is a conductive material, when the device is in a power generation or power supply state, there is an electrical connection between the conductive part, the busbar and the second solder strip, the first solder strip and the grid line of the back contact battery, and the second solder strip and the grid line of the back contact battery.

[0109] Unless otherwise stated, "substantially identical" within the measurement tolerance or manufacturing error range is equivalent to "identical" or "equal" in the description of the embodiments of this application.

[0110] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0111] As can be seen from the above description, the embodiments described in this application achieve the following technical effects:

[0112] This application achieves a piezoelectric connection between the busbar and the second solder strip by having one end of the conductive part contact the busbar and the other end contact the second solder strip. This avoids welding the busbar and solder strip through hot pressing or mechanical pressure, fundamentally eliminating the path of welding stress transmission to the solar cell. This significantly reduces the risk of microcracks in the solar cell caused by thermal or mechanical stress, and improves the structural reliability and long-term operational stability of the module. At the same time, by placing an insulating strip between the busbar and the first solder strip, the electrical contact between the busbar and the first solder strip is physically isolated. This allows the busbar to be placed on the back side of the back contact cell, avoiding the problem of the busbar and the back contact cell occupying module area when placed on the same layer, thus affecting the effective light-receiving area of ​​the solar cell.

[0113] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A photovoltaic module, characterized in that, include: A battery string includes multiple back contact batteries, multiple first solder strips, multiple second solder strips, and multiple insulating strips. The multiple back contact batteries are arranged sequentially along a first direction. The first solder strips and second solder strips are alternately arranged on one side of the back of the multiple back contact batteries along a second direction. The multiple insulating strips are located on the side of the multiple first solder strips away from the back contact batteries. The first direction intersects the second direction. In the battery string, any two adjacent back contact batteries satisfy at least one of the following: having a gap, being adjacent, or partially overlapping in a third direction. The third direction is perpendicular to the first direction and the second direction, respectively. The busbar is located on the side of the plurality of insulating strips away from the plurality of first solder strips, and intersects with the plurality of first solder strips and the plurality of second solder strips respectively; Multiple conductive parts, one end of which contacts the side of the busbar and the other end of which contacts the surface of the second solder strip, wherein the side of the busbar is at least one of two surfaces of the busbar that are opposite each other along the first direction.

2. The photovoltaic module according to claim 1, characterized in that, The second solder strip is located between the busbar and the back contact battery, and the other end of the conductive part contacts the surface of the second solder strip away from the back contact battery.

3. The photovoltaic module according to claim 2, characterized in that, One end of the conductive portion extends from the side of the busbar to the surface of the busbar away from the back contact battery. The portion of the conductive portion on the surface of the busbar away from the back contact battery has a thickness of less than or equal to 50 μm in a third direction, which is perpendicular to the first direction and the second direction, respectively.

4. The photovoltaic module according to claim 1, characterized in that, The second solder strip is located on the side of the busbar away from the back contact battery, and the other end of the conductive part contacts the surface of the second solder strip near the back contact battery.

5. The photovoltaic module according to claim 1, characterized in that, In the battery string, two adjacent back contact batteries located at non-head and tail positions along the first direction are respectively a first battery cell and a second battery cell, and the bus bar is located on the second battery cell; the first battery cell and the second battery cell are connected in series by the second solder strip; the first solder strip on the first battery cell and the first solder strip on the second battery cell are aligned in the first direction and have a gap.

6. The photovoltaic module according to claim 1, characterized in that, In the battery string, two adjacent back contact batteries located at non-head and tail positions along the first direction are respectively a first battery cell and a second battery cell, and the bus bar is located on the second battery cell; the first battery cell and the second battery cell are connected in series by the second solder strip; the first solder strip on the first battery cell has an extension extending to the second battery cell, and the extension is staggered with the first solder strip on the second battery cell in the first direction and overlaps in the second direction.

7. The photovoltaic module according to claim 6, characterized in that, In the third direction, the extension overlaps with the insulating strip, and the third direction is perpendicular to the first direction and the second direction, respectively.

8. The photovoltaic module according to any one of claims 1 to 7, characterized in that, The width of the insulating strip in the second direction is greater than or equal to 1.5 times the width of the first solder strip in the second direction, and less than or equal to 3 / 4 of the distance between the first solder strip and the second solder strip.

9. The photovoltaic module according to any one of claims 1 to 7, characterized in that, The width of the conductive part in the first direction is 1~2mm, and the width of the conductive part in the second direction is 2~8mm.

10. The photovoltaic module according to any one of claims 1 to 7, characterized in that, The photovoltaic module includes multiple battery string groups and multiple busbars, and each battery string group includes two battery strings arranged along the second direction; In each of the battery strings, the back contact batteries located at the beginning and end along the first direction are end battery cells, and the back contact batteries located in the middle along the first direction are middle battery cells. The plurality of busbars include end busbars and intermediate busbars. The two ends of the end busbars are respectively located on the back side of two end cells in the battery string, and the two ends of the intermediate busbars are respectively located on the back side of adjacent intermediate cells in two battery string.

11. A method for preparing a photovoltaic module, used to prepare the photovoltaic module according to any one of claims 1 to 10, characterized in that, include: A battery string is provided, the battery string including a plurality of back contact batteries, a plurality of first solder strips, a plurality of second solder strips and a plurality of insulating strips, the plurality of back contact batteries being arranged sequentially along a first direction, the first solder strips and the second solder strips being alternately arranged along a second direction on one side of the back of the plurality of back contact batteries, the plurality of insulating strips being located on the side of the plurality of first solder strips away from the back contact batteries, the first direction intersecting the second direction; A busbar is provided on the side of the plurality of insulating strips away from the plurality of first solder strips, and the busbar intersects with the plurality of first solder strips and the plurality of second solder strips respectively; A plurality of conductive portions are formed on the surface of the busbar, one end of which contacts the side of the busbar and the other end of which contacts the second solder strip, wherein the side of the busbar is at least one of two surfaces of the busbar that are opposite each other along the first direction.

12. The method for preparing a photovoltaic module according to claim 11, characterized in that, Forming a plurality of conductive portions, one end of which contacts the side of the busbar and the other end of which contacts the surface of the second solder strip, including: Heat the alloy material to a molten state; The molten alloy material is non-contactly coated at the intersection of the busbar and the second solder strip, so that the alloy material contacts the side of the busbar and the surface of the second solder strip respectively, forming multiple pre-conductive parts; The plurality of the prepared conductive parts are cooled to solidify, thereby obtaining the conductive parts.

13. A photovoltaic module manufacturing apparatus for manufacturing the photovoltaic module according to any one of claims 1 to 10, characterized in that, include: A fabrication unit is used to fabricate a battery string, the battery string including multiple back contact batteries, multiple first solder strips, multiple second solder strips and multiple insulating strips. The multiple back contact batteries are arranged sequentially along a first direction, the first solder strips and the second solder strips are alternately arranged along a second direction on one side of the back of the multiple back contact batteries, and the multiple insulating strips are located on the side of the multiple first solder strips away from the back contact batteries. The first direction intersects the second direction. Setting unit, used to set busbar on the side of the plurality of insulating strips away from the plurality of first solder strips, wherein the busbar intersects with the plurality of first solder strips and the plurality of second solder strips respectively; A drop-welding unit is used to form a plurality of conductive portions on a surface that has one end in contact with a side of the busbar and the other end in contact with the second solder strip, wherein the side of the busbar is at least one of two surfaces of the busbar that are opposite each other along the first direction.

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