Back contact photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a back contact photovoltaic module, which comprises a back contact battery comprising a battery body and a plurality of second grid line segments, the battery body is provided with a front surface and a back surface which are opposite to each other, and the back surface comprises a first edge, a middle area and a second edge which are sequentially arranged along a first direction, the plurality of second grid line segments are located on the first edge and the second edge; the plurality of first electric connection parts are arranged at intervals along a first direction; the fixing parts are located on the first edge and the second edge, the fixing parts and the first electric connection parts are not overlapped in the thickness direction of the back contact battery, and the first direction is perpendicular to the thickness direction; in the first direction, the distance between the fixing part and the first electric connecting part is larger than or equal to 1 / 2 of the width of the first electric connecting part. The problem that the welding reliability of the back contact photovoltaic module is poor is solved.

Description

[0001] Cross-reference to related applications

[0002] This application is a divisional application of Chinese invention patent application filed on August 6, 2025, with application number 2025110999369 and invention title "Back Contact Photovoltaic Module". Technical Field

[0003] This application relates to the photovoltaic field, and in particular to a back-contact photovoltaic module. Background Technology

[0004] Currently, in the manufacturing of photovoltaic modules, back-contact (BC) photovoltaic modules have received widespread attention due to their high efficiency and excellent performance. However, back-contact photovoltaic modules currently suffer from poor welding reliability. Summary of the Invention

[0005] This application provides a back-contact photovoltaic module, which at least solves the problem of poor welding reliability of back-contact photovoltaic modules.

[0006] According to some embodiments of this application, one aspect of this application provides a back-contact photovoltaic module, including: a back-contact cell, including a cell body and a plurality of second grid segments, the cell body having a front side and a back side, the back side including a first edge, a middle area and a second edge arranged sequentially along a first direction, the plurality of second grid segments being located at the first edge and the second edge; a plurality of first electrical connections arranged at intervals along the first direction; a fixing part located at the first edge and the second edge, along the thickness direction of the back-contact cell, the fixing part not overlapping with the first electrical connections, the first direction being perpendicular to the thickness direction; in the first direction, the distance between the fixing part and the first electrical connections is greater than or equal to 1 / 2 of the width of the first electrical connections.

[0007] In some embodiments, the width of the second gate segment in the second direction is 200μm to 250μm, and the second direction intersects with the first direction.

[0008] In some embodiments, the length of the second gate segment along the first direction is 20mm to 25mm.

[0009] In some embodiments, the back-contact photovoltaic module further includes a solder ribbon located on the surface of a plurality of first electrical connections away from the second grid segment. Along the thickness direction, the solder ribbon overlaps with the second grid segment. The fixing portion is also located on at least one side of the solder ribbon, the side being one of two opposing surfaces of the solder ribbon in a second direction. The thickness of the fixing portion in the second direction is 100 μm to 150 μm, and the second direction intersects the first direction.

[0010] In some embodiments, the maximum distance between the fixing portion located at the target edge and the edge line of the target edge is less than or equal to 10 mm, and the target edge is the first edge or the second edge.

[0011] In some embodiments, one of the second gate segments corresponds to one or two of the fixing portions.

[0012] In some embodiments, the back-contact photovoltaic module further includes a first sub-grid line and a second sub-grid line alternately spaced along the first direction at the first edge, the middle region, and the second edge, the first sub-grid line and the second sub-grid line having opposite polarities, the first sub-grid line and the second sub-grid line extending along a second direction, the second direction intersecting the first direction, and the back-contact photovoltaic module further includes: a plurality of second electrical connection portions spaced along the first direction on the surface of the first sub-grid line or the second sub-grid line away from the battery body.

[0013] In some embodiments, the cross-sectional shape of the second grid segment includes at least one of the following: rectangular, elliptical, circular, trapezoidal, or irregular polygonal, and the cross-section of the second grid segment is perpendicular to the thickness direction of the back contact battery.

[0014] In some embodiments, the cross-sectional shape of the first electrical connection includes at least one of the following: rectangular, elliptical, circular, trapezoidal, or irregular polygonal, and the cross-section of the first electrical connection is perpendicular to the thickness direction of the back contact battery.

[0015] In some embodiments, in the first direction, the distance between the fixing portion and the first electrical connection portion is less than or equal to the width of the first electrical connection portion.

[0016] In some embodiments, the second gate segment located at the first edge and the second edge is offset along the middle region.

[0017] In some embodiments, the fixing portion is also located on the surface of the welding strip away from the battery body.

[0018] The technical solution provided in this application has at least the following advantages: In the back-contact photovoltaic module of this application, the fixing part is set in the edge area of ​​the cell, and the fixing part and the first electrical connection part do not overlap in the thickness direction of the back-contact cell. This allows the fixing part and the first electrical connection part to be arranged at intervals in the first direction. This not only allows the fixing part to fix the solder ribbon, but also avoids the fixing part from penetrating into the first electrical connection part before curing, which could easily cause the problem of poor soldering between the first electrical connection part and the solder ribbon after the lamination process. This ensures a better welding effect and higher reliability of the back-contact cell. Furthermore, by controlling the interval between the fixing part and the first connection part in the first direction to be less than or equal to 1 / 2 of the width of the first electrical connection part, sufficient space is ensured between the two. This avoids the problem of the fixing part flowing into the first electrical connection part before curing, causing glue seepage and affecting the welding effect between the first electrical connection part and the solder ribbon, further ensuring a better connection reliability of the first electrical connection part. Attached Figure Description

[0019] 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.

[0020] Figure 1 This is an EL (Electroluminescence Test) image of an existing back-contact photovoltaic module;

[0021] Figure 2 This is a top view of a back-contact photovoltaic module provided in one embodiment of this application;

[0022] Figure 3 This is a side view of a back-contact photovoltaic module provided in one embodiment of this application;

[0023] Figure 4 This is a three-dimensional structural schematic diagram of a back-contact photovoltaic module provided in one embodiment of this application;

[0024] Figure 5 This is an EL image of a back-contact photovoltaic module provided in one embodiment of this application.

[0025] The above figures include the following reference numerals:

[0026] 10. Battery body; 11. First grid line; 111. First sub-grid line; 112. Second sub-grid line; 12. Second grid line segment; 13. First edge; 14. Middle area; 15. Second edge; 16. Solder ribbon; 17. First electrical connection part; 18. Fixing part; 19. First solder pad; 20. Second solder pad; 21. Second electrical connection part; 22. Adhesive film. Detailed Implementation

[0027] As the background technology shows, current back-contact photovoltaic modules fix the solder ribbon and the cell by dispensing and curing, and then achieve the welding of the solder ribbon and the cell by lamination process. After dispensing, the UV adhesive can easily penetrate between the solder ribbon and the solder paste, causing poor soldering between the solder ribbon and the solder paste, resulting in poor welding of the back-contact photovoltaic module. Figure 1 An exemplary example is shown: a test image of a photovoltaic module with a poorly soldered back contact after EL testing, such as... Figure 1 As shown, there is obvious blackening at the edge of the back contact photovoltaic module.

[0028] To address the aforementioned technical problem, this application provides a back-contact photovoltaic module, comprising: a back-contact cell, including a cell body, a plurality of first grid lines, and a plurality of second grid line segments. The cell body has a front side and a back side. The back side includes a first edge, a middle area, and a second edge arranged sequentially along a first direction. The plurality of first grid lines extend along a second direction and are spaced apart along the first direction at the first edge, the middle area, and the second edge. The plurality of second grid line segments intersect with portions of the first grid lines and are located at the first edge and the second edge. The first direction intersects with the second direction. A plurality of solder ribbons are located on the back side and cover the second grid line segments. A plurality of first electrical connection portions are spaced apart along the first direction between the solder ribbons and the second grid line segments and respectively contact the solder ribbons and the second grid line segments. A fixing portion is located at the first edge and the second edge for fixing the solder ribbons to the back-contact cell. Along the thickness direction of the back-contact cell, the fixing portion does not overlap with the first electrical connection portions.

[0029] 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.

[0030] 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.

[0031] 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 it have an "or" relationship.

[0032] 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).

[0033] 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.

[0034] In the description of the embodiments of this application, unless otherwise expressly specified and limited, 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 terms in the embodiments of this application can be understood according to the specific circumstances.

[0035] 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.

[0036] 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.

[0037] The terminology used in the description of the various embodiments 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 "part" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0038] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the 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.

[0039] One embodiment of this application provides a back-contact photovoltaic module, such as... Figure 2 , Figure 3 as well as Figure 4 As shown, the back-contact photovoltaic module includes:

[0040] A back-contact battery includes a battery body 10, a plurality of first grid lines 11, and a plurality of second grid line segments 12. The battery body has a front side and a back side. The back side includes a first edge 13, a middle area 14, and a second edge 15 arranged sequentially along a first direction. The plurality of first grid lines 11 extend along a second direction and are spaced apart along the first direction at the first edge 13, the middle area 14, and the second edge 15. The plurality of second grid line segments 12 intersect with a portion of the first grid lines 11 and are located at the first edge 13 and the second edge 15. The first direction intersects with the second direction.

[0041] Specifically, the first edge 13, the middle area 14, and the second edge 15 refer to three areas on the back side of the back contact battery. The first grid line 11 is disposed on the first edge 13, the middle area 14, and the second edge 15. The second grid line segments 12 are disposed on the first edge 13 and the second edge 15. Each second grid line segment 12 intersects only a portion of the first grid line 11, achieving electrical contact between the second grid line segment 12 and this portion of the first grid line 11. Optionally, a plurality of second grid line segments 12 extend along the first direction and are spaced apart along the second direction. The length of the first grid line 11 in the second direction is greater than the length of the second grid segment 12 in the first direction. Optionally, the first direction is perpendicular to the second direction.

[0042] Multiple solder strips 16 are located on the back side and cover the second gate segment 12;

[0043] Optionally, the plurality of the welding strips 16 extend along the first direction and are spaced apart along the second direction.

[0044] Multiple first electrical connection portions 17 are arranged at intervals between the solder strip 16 and the second gate line segment 12 along the first direction, and are in contact with the solder strip 16 and the second gate line segment 12 respectively;

[0045] Specifically, the first electrical connection portion 17 is used to electrically connect the solder strip 16 and the second gate line segment 12. At the intersection of the first gate line 11 and the second gate line segment 12, the first electrical connection portion 17 is electrically connected to both the first gate line 11 and the second gate line segment 12.

[0046] The fixing part 18 is located at the first edge 13 and the second edge 15 and is used to fix the welding strip 16 to the back contact battery. Along the thickness direction of the back contact battery, the fixing part 18 does not overlap with the first electrical connection part 17.

[0047] Specifically, the orthographic projection of the fixing part 18 on the battery body 10 and the orthographic projection of the first electrical connection part 17 on the battery body 10 are arranged at intervals without overlapping. The fixing part 18 is used to form a stable connection and fixation between the solder strip 16 and the second grid line segment 12.

[0048] In the aforementioned embodiment, the fixing part is disposed in the edge area of ​​the battery cell, and the fixing part and the first electrical connection part do not overlap in the thickness direction of the back contact battery. This allows the fixing part and the first electrical connection part to be arranged at intervals in the first direction. In this way, the fixing part can not only fix the solder ribbon, but also prevent the fixing part from penetrating into the first electrical connection part before curing, which could easily cause the problem of poor soldering between the first electrical connection part and the solder ribbon after the lamination process. This ensures that the welding effect of the back contact battery is good and the reliability is high.

[0049] Specifically, the statement that the solder ribbon 16 covers the second gate line segment 12 can mean that the solder ribbon 16 partially covers the second gate line segment 12, that is, the solder ribbon 16 covers a portion of the second gate line segment 12; or it can mean that the solder ribbon 16 completely covers the second gate line segment 12, that is, the solder ribbon 16 covers the entire second gate line segment 12.

[0050] In practical applications, the back contact battery in this application can be a whole structure obtained by cutting a silicon rod, or it can be a whole structure further cut into n segments, where n ≥ 2 and n is an integer. For example, when n = 2, the back contact battery is a two-segment battery; when n = 3, the back contact battery is a three-segment battery; and when n = 4, the back contact battery is a four-segment battery.

[0051] Optionally, such as Figure 2 As shown, the second grid segment 12 is only disposed at the first edge 13 and the second edge 15, and not in the middle region 14. This reduces the amount of material used in the second grid segment 12; at the same time, the current in the head and tail edge regions of the back contact battery is discharged through the second grid segment 12, which improves the ability of the solder ribbon 16 to collect the current in the back contact battery and solves the problem of low edge current collection efficiency; in addition, the second grid segment 12 ensures a large contact area between the solder ribbon 16 and the back contact battery, which improves the welding pull of the solder ribbon 16 in the edge region and further reduces the risk of poor soldering of the solder ribbon 16.

[0052] Optionally, the second gate line segments 12 located at the first edge 13 and the second edge 15 can be symmetrically arranged along the intermediate region 14, with one solder strip 16 correspondingly covering one second gate line segment 12 at the first edge 13 and one second gate line segment 12 at the second edge 15. Optionally, the second gate line segments 12 located at the first edge 13 and the second edge 15 can be staggered, with one solder strip 16 correspondingly covering one second gate line segment 12 at the first edge 13 or one second gate line segment 12 at the second edge 15.

[0053] In some embodiments, the back-contact photovoltaic module is a grid-less back-contact photovoltaic module. In other embodiments, the back-contact photovoltaic module may also be a grid-connected back-contact photovoltaic module.

[0054] In practical applications, the welding strip 16 is a component for transmitting current, and its main function is to transmit and collect current. The welding strip 16 can be a round welding strip 16 or a flat welding strip 16.

[0055] In some embodiments, the material of the fixing part 18 includes UV adhesive. For example, the fixing part 18 can be made of UV adhesive. UV adhesive, as the material of the fixing part 18, has a fast curing speed.

[0056] Of course, the material of the fixing part 18 is not limited to the UV adhesive, but can also be silicone and epoxy resin adhesive, etc.

[0057] In one alternative embodiment, the cross-sectional shape of the second grid segment 12 includes at least one of the following: rectangular, elliptical, circular, trapezoidal, or irregular polygonal, and the cross-section of the second grid segment 12 is perpendicular to the thickness direction of the back contact battery. The cross-sectional shape design of the second grid segment 12 aims to optimize the current transmission path and reduce resistance loss. Different cross-sectional shapes, such as rectangular, elliptical, circular, trapezoidal, or irregular polygonal, can adapt to different current requirements and component designs, improving current collection efficiency.

[0058] In some embodiments, the material of the first electrical connection portion 17 includes tin. For example, the first electrical connection portion 17 can be solder paste. Solder paste has good conductivity and solderability.

[0059] Of course, the material of the first electrical connection part 17 is not limited to tin, but can also be lead-free solder alloy, silver-based conductive adhesive, copper-based conductive adhesive, and nickel-based conductive adhesive, etc.

[0060] In another alternative embodiment, the cross-sectional shape of the first electrical connection portion 17 includes at least one of the following: rectangular, elliptical, circular, trapezoidal, or irregular polygonal, wherein the cross-section of the first electrical connection portion 17 is perpendicular to the thickness direction of the back contact battery. The cross-sectional shape of the first electrical connection portion 17 also has a significant impact on current transmission efficiency. By selecting a suitable cross-sectional shape, such as rectangular, elliptical, circular, trapezoidal, or irregular polygonal, the contact area and current distribution of the electrical connection can be optimized, reducing contact resistance. This design solves the problem of electrical connection optimization, including but not limited to improving the electrical performance and reliability of components in complex circuit layouts by adjusting the cross-sectional shape of the first electrical connection portion 17.

[0061] In some embodiments, in the first direction, the minimum distance between the fixing part 18 and the first electrical connection part 17 is greater than or equal to half the width of the first electrical connection part 17. By controlling the spacing between the fixing part 18 and the first connection part in the first direction, sufficient space is ensured between them, further preventing the fixing part 18 from flowing into the first electrical connection part 17 before curing and causing glue seepage, which would affect the welding effect between the first electrical connection part 17 and the solder ribbon 16. This further ensures a better connection reliability between the first electrical connection part 17 and the solder ribbon 16.

[0062] Specifically, the minimum distance refers to the minimum straight-line distance between the edge of the fixing part 18 and the edge of the first electrical connection part 17.

[0063] In other embodiments, in the first direction, the minimum distance between the fixing part 18 and the first electrical connection part 17 is less than or equal to the width of the first electrical connection part 17. This ensures high space utilization of the back-contact photovoltaic module and balances the electrical performance and mechanical stability of the back-contact photovoltaic module.

[0064] It should be noted that the width of the first electrical connection portion 17 refers to the width of the first electrical connection portion 17 in the first direction.

[0065] Specifically, the width of the second grid segment 12 in the second direction is 200μm to 250μm. For example, the width of the second grid segment 12 in the second direction can be 200μm, 210μm, 220μm, 230μm, 240μm, or 250μm, etc. Designing the width of the second grid segment 12 to be between 200μm and 250μm makes the second grid segment 12 wider. This ensures that the second grid segment 12 can carry a larger current, reducing resistance loss. The wider second grid segment 12 can also provide greater tensile strength, further reducing the phenomenon of poor soldering of the solder strip 16, thereby further improving the reliability of the back contact photovoltaic module. It can also ensure high mechanical strength of the back contact cell edge, thereby enhancing the durability of the back contact photovoltaic module.

[0066] In some embodiments, the length of the second grid segment 12 along the first direction is 20mm to 25mm. For example, the length of the second grid segment 12 in the first direction can be 20mm, 21mm, 22mm, 23mm, 24mm, or 25mm, etc. Designing the length of the second grid segment 12 to be between 20mm and 25mm can reduce the amount of material used in the second grid segment 12 and improve the current collection efficiency in the edge region of the back contact battery, thereby improving the current collection capability of the solder ribbon 16 in the back contact battery.

[0067] According to some embodiments of this application, the fixing part 18 is also located on at least one side of the solder ribbon 16, the side being one of two opposing surfaces of the solder ribbon 16 in the second direction, and the thickness of the fixing part 18 in the second direction is 100μm to 150μm. For example, the thickness of the fixing part 18 in the second direction can be 100μm, 110μm, 120μm, 130μm, 140μm, or 150μm, etc. By placing the fixing part 18 on at least one side of the solder ribbon 16 and contacting the back of the back contact cell, the adhesion between the solder ribbon 16 and the back contact cell is improved, thereby further ensuring a good fixing effect of the fixing part 18 on the solder ribbon 16, and further avoiding the problem of the solder ribbon 16 loosening and shifting during photovoltaic module manufacturing, affecting the performance of the back contact photovoltaic module. Designing the thickness of the fixing part 18 between 100μm and 150μm ensures both a good fixing effect and that the fixing part 18 occupies an appropriate packaging space.

[0068] In some embodiments, such as Figure 2 As shown, the fixing part 18 may be located only on the side of the welding strip 16; in other embodiments, such as Figure 4 As shown, the fixing part 18 can be located on the side of the solder strip 16 and on the surface of the solder strip 16 away from the battery body 10.

[0069] In some embodiments, one second grid segment 12 corresponds to one or two of the fixing parts 18. One or two fixing parts 18 can fix the solder strip 16 without occupying too much of the photovoltaic module's encapsulation space, ensuring a high space utilization rate for the photovoltaic module.

[0070] Those skilled in the art can reasonably configure the number of the fixing parts 18 to ensure the reliable fixing function of the solder strip 16, and are not limited to one or two as described above. For example, one second gate segment 12 may correspond to multiple fixing parts 18.

[0071] In practical applications, when one welding strip 16 corresponds to one fixing part 18, the fixing part 18 is located on one side of the welding strip 16. When one welding strip 16 corresponds to multiple fixing parts 18, the multiple fixing parts 18 can be located on the same side of the welding strip 16 or on two sides of the welding strip 16. When the fixing parts 18 are located on two sides of the welding strip 16, along the first direction, the fixing parts 18 located on the two sides can be symmetrically arranged or staggered.

[0072] In some embodiments, the maximum distance between the fixing part 18 located at the target edge and the edge line of the target edge is less than or equal to 10 mm, and the target edge is the first edge 13 or the second edge 15. For example, the maximum distance between the fixing part 18 and the target edge can be 10 mm, 9 mm, 8 mm, 7 mm, or 6 mm, etc. By setting the fixing part 18 at the beginning and end edges of the back contact battery and setting the distance between the fixing part 18 and the edge, the fixing part 18 fixes the beginning and end of the solder strip 16, further ensuring a better fixing effect of the fixing part 18.

[0073] Specifically, the maximum distance refers to the maximum value of the distance between the edge of the fixing part 18 and the edge line of the target edge.

[0074] According to some other embodiments of this application, the maximum distance between the fixing part 18 located at the edge of the target and the edge line of the target edge is greater than 0 mm.

[0075] In some embodiments, the plurality of first grid lines 11 include first sub-grid lines 111 and second sub-grid lines 112 alternately spaced along the first direction, wherein the first sub-grid lines 111 and second sub-grid lines 112 have opposite polarities. The back-contact photovoltaic module further includes: a plurality of second electrical connection portions 21, arranged at intervals along the first direction between the first sub-grid lines 111 and the solder ribbon 16 or between the second sub-grid lines 112 and the solder ribbon 16; and the second electrical connection portions 21 are in contact with the solder ribbon 16 and the first sub-grid lines 111 respectively, or the second electrical connection portions 21 are in contact with the solder ribbon 16 and the second sub-grid lines 112 respectively. The alternately spaced first sub-grid lines 111 and second sub-grid lines 112 enable the separate collection of electrons and holes in the cell, and then transfer them to the solder ribbon 16.

[0076] Specifically, the second electrical connection portion 21 is located in the intermediate region 14. The second electrical connection portion 21 is used to electrically connect the solder strip 16 to the first sub-gate line 111, or to electrically connect the solder strip 16 to the second sub-gate line 112. Among the plurality of solder strips 16 in this application, the polarity of some solder strips 16 is the same as the polarity of the first sub-gate line 111, and the polarity of different solder strips 16 is the same as the polarity of the second sub-gate line 112.

[0077] Furthermore, a portion of the polarity of the plurality of second gate line segments 12 is the same as that of the first sub-gate line 111, and the remaining portion of the plurality of second gate line segments 12 is the same as that of the second sub-gate line 112. The plurality of second gate line segments 12 with different polarities are arranged alternately at intervals along the second direction.

[0078] To ensure insulation between the solder strips 16 of different polarities and the first grid line 11, in one embodiment, the back contact battery further includes a plurality of first insulating portions (not shown in the figure). The first insulating portions are located between the solder strips 16 of different polarities and the first grid line 11 to achieve electrical insulation between the two. Of course, the first insulating portions may not be provided. In another embodiment, the first grid line 11, which has a polarity different from that of the solder strip 16, is disconnected on both sides of the solder strip 16.

[0079] To ensure insulation between the second grid segment 12 and the first grid line 11 of different polarities, in one embodiment, the back contact battery further includes a plurality of second insulating portions (not shown in the figure). The second insulating portions are located between the second grid segment 12 and the first grid line 11 of different polarities to achieve electrical insulation between them. Of course, the second insulating portions may not be provided. In another embodiment, the first grid line 11, which has a polarity different from that of the second grid segment 12, is disconnected on both sides of the second grid segment 12.

[0080] Specifically, the materials of the second electrical connection portion 21 include, but are not limited to, solder paste, lead-free solder alloy, and conductive adhesive.

[0081] In some embodiments, the cross-sectional shape of the second electrical connection portion 21 includes at least one of the following: rectangular, elliptical, circular, trapezoidal, or irregular polygonal, and the cross-section of the second electrical connection portion 21 is perpendicular to the thickness direction of the back contact battery.

[0082] Optionally, the second electrical connection portion 21 and the first electrical connection portion 17 may be made of the same material or different materials. The cross-sectional shape of the second electrical connection portion 21 may be the same as or different from the cross-sectional shape of the first electrical connection portion 17.

[0083] In some embodiments, the width of the second gate segment 12 in the second direction is 20 to 30 times the width of the first gate line 11 in the first direction. For example, the width of the second gate segment 12 in the second direction can be 20, 22, 23, 25, 27, 29, or 30 times the width of the first gate line 11 in the first direction. In this embodiment, by setting the width of the second gate segment 12 to be greater than the width of the first gate line 11, the current collection efficiency of the second gate segment 12 can be further ensured, so that the second gate segment 12 can draw the current from the first edge 13 and the second edge 15.

[0084] Optionally, in the preparation process of the back contact photovoltaic module, after the solder ribbon 16 is placed on the side away from the back contact cell of the first electrical connection portion 17 and the second electrical connection portion 21, the fixing portion 18 is first formed on the side of the solder ribbon 16 by low temperature dispensing technology, then the fixing portion 18 is cured, and finally the good welding between the solder ribbon 16 and the first electrical connection portion 17, and between the solder ribbon 16 and the second electrical connection portion 21 is achieved by lamination technology.

[0085] According to some embodiments of this application, the back-contact photovoltaic module further includes a plurality of first solder pads 19. The plurality of first solder pads 19 are located in the intermediate region 14 and are arranged at intervals along the first direction. The first solder pads 19 are located between the first grid line 11 and the second electrical connection portion 21; that is, the second electrical connection portion 21 may be located between the first solder pad 19 and the solder ribbon 16. The orthographic projection of the first solder pad 19 on the back side is greater than or equal to the orthographic projection of the second electrical connection portion 21 on the back side. By setting the first solder pads 19, the contact area between the second electrical connection portion 21 and the first grid line 11 is increased, which can reduce the contact resistance between the second electrical connection portion 21 and the first grid line 11 and improve the contact quality between them.

[0086] In the manufacturing process of back-contact photovoltaic modules, the first pad 19 and the first grid line 11 can be integrally formed, or the first grid line 11 can be printed on the back side of the back-contact cell first, and then the first pad 19 can be printed.

[0087] Furthermore, the back-contact photovoltaic module may also include a plurality of second pads 20, which are located at the first edge 13 and the second edge 15. The second pads 20 are also located between the second grid segment 12 and the first electrical connection portion 17; that is, the first electrical connection portion 17 may be located between the second pads 20 and the solder strip 16. The orthographic projection of the second pads 20 on the back side is greater than or equal to the orthographic projection of the first electrical connection portion 17 on the back side. By providing the second pads 20, the contact area between the first electrical connection portion 17 and the second grid segment 12 is increased, which can reduce the contact resistance between the first electrical connection portion 17 and the second grid segment 12, thereby improving the contact quality between them.

[0088] Similarly, in the manufacturing process of back-contact photovoltaic modules, the second pad 20 and the second grid segment 12 can be integrally formed, or the second grid segment 12 can be printed on the back of the back-contact cell first, and then the second pad 20 can be printed.

[0089] In practical applications, the width of the second pad 20 in the first direction is greater than the width of the first pad 19 in the first direction.

[0090] like Figure 4 As shown, the back-contact photovoltaic module also includes an adhesive film 22 located on the surface of the battery body 10, the solder ribbon 16, and the fixing part 18.

[0091] The test images obtained by performing EL testing on the back-contact photovoltaic module of this application are as follows: Figure 5 As shown, comparison Figure 1 and Figure 5 It is evident that the back-contact photovoltaic module of this application does not exhibit blackening at the edge. Compared with the prior art, this application significantly improves the problem of poor edge soldering in back-contact photovoltaic modules.

[0092] The back-contact photovoltaic module described in this application will be specifically described below with reference to specific embodiments and comparative examples.

[0093] Example 1

[0094] This embodiment provides a back-contact photovoltaic module, including:

[0095] A back-contact battery includes a battery body, a plurality of first grid lines, and a plurality of second grid line segments. The battery body has a front side and a back side. The back side includes a first edge, a middle area, and a second edge arranged sequentially along a first direction. The plurality of first grid lines extend along a second direction and are spaced apart along the first direction at the first edge, the middle area, and the second edge. The plurality of second grid line segments intersect with a portion of the first grid lines and are located at the first edge and the second edge. The first direction intersects with the second direction. The width of the second grid line segment in the second direction is 220 μm, and the length of the second grid line segment is 23 mm.

[0096] Multiple solder strips are located on the back side and cover the second gate line segment;

[0097] Multiple first electrical connection portions are spaced apart between the solder strip and the second gate line segment along the first direction, and are in contact with the solder strip and the second gate line segment respectively;

[0098] A fixing part, located at the first edge and the second edge, is used to fix the welding strip to the back contact battery. Along the thickness direction of the back contact battery, the fixing part does not overlap with the first electrical connection part.

[0099] Example 2

[0100] This embodiment provides a back-contact photovoltaic module. The only difference between this back-contact photovoltaic module and Embodiment 1 is that the width of the second grid segment in the second direction is 200 μm.

[0101] Example 3

[0102] This embodiment provides a back-contact photovoltaic module. The only difference between this back-contact photovoltaic module and Embodiment 1 is that the width of the second grid segment in the second direction is 250 μm.

[0103] Example 4

[0104] This embodiment provides a back-contact photovoltaic module, the only difference between this back-contact photovoltaic module and Embodiment 1 is that the length of the second grid segment is 20mm.

[0105] Example 5

[0106] This embodiment provides a back-contact photovoltaic module, the only difference between this back-contact photovoltaic module and Embodiment 1 is that the length of the second grid segment is 25mm.

[0107] Comparative Example 1

[0108] This embodiment provides a back-contact photovoltaic module. The only difference between this back-contact photovoltaic module and Embodiment 1 is that the width of the second grid segment in the second direction is 150 μm.

[0109] Comparative Example 2

[0110] This embodiment provides a back-contact photovoltaic module. The only difference between this back-contact photovoltaic module and Embodiment 1 is that the width of the second grid segment in the second direction is 300 μm.

[0111] Comparative Example 3

[0112] This embodiment provides a back-contact photovoltaic module, the only difference between this back-contact photovoltaic module and Embodiment 1 is that the length of the second grid segment is 15mm.

[0113] Comparative Example 4

[0114] This embodiment provides a back-contact photovoltaic module, the only difference between this back-contact photovoltaic module and Embodiment 1 is that the length of the second grid segment is 30mm.

[0115] Comparative Example 5

[0116] This embodiment provides a back-contact photovoltaic module. The only difference between this back-contact photovoltaic module and Embodiment 1 is that the length of the second grid segment is 100mm and the width in the second direction is 10mm.

[0117] Performance tests were conducted on the back-contact photovoltaic modules corresponding to each example in Examples 1-5 and Comparative Examples 1-5. The test results are shown in Table 1.

[0118] Table 1

[0119]

[0120] The experimental data show that the power decay and the proportion of cold solder joints at the EL (Electronic Energy Transfer) head and tail after TC (Temperature Cycling) in Examples 1-5 are lower than those in Comparative Examples 1, 3, and 5. This indicates that the increased length and width of the second grid segment reduces the power decay and the proportion of cold solder joints at the EL head and tail after TC. The power decay in Examples 1-5 can be reduced to below 3%, and the proportion of cold solder joints can be reduced to below 1%, significantly reducing the risk of cold solder joints after TC. Furthermore, compared to Comparative Examples 2 and 4, the overall area occupied by the second grid segment in Examples 1-5 is smaller, balancing the reliability of the back contact battery with space utilization.

[0121] As can be seen from the above description, the embodiments described in this application achieve the following technical effects:

[0122] In the back-contact photovoltaic module of this application, the fixing part is set in the edge area of ​​the cell, and the fixing part and the first electrical connection part do not overlap in the thickness direction of the back-contact cell. This makes the fixing part and the first electrical connection part arranged at intervals in the first direction. In this way, the fixing part can play the role of fixing the solder ribbon, and it can also prevent the fixing part from penetrating into the first electrical connection part before curing, which can easily cause the problem of poor soldering between the first electrical connection part and the solder ribbon after the lamination process. This ensures that the welding effect of the back-contact cell is good and the reliability is high.

[0123] Those skilled in the art will understand that the various embodiments described are specific examples of implementing this application, and in practical applications, various changes in form and detail may 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 back-contact photovoltaic module, characterized in that, include: The back contact battery includes a battery body and a plurality of second grid segments. The battery body has a front side and a back side, and the back side includes a first edge, a middle area and a second edge arranged sequentially along a first direction. The plurality of second grid segments are located at the first edge and the second edge. Multiple first electrical connection portions are arranged at intervals along the first direction; A fixing part is located at the first edge and the second edge, along the thickness direction of the back contact battery. The fixing part does not overlap with the first electrical connection part, and the first direction is perpendicular to the thickness direction. In the first direction, the distance between the fixing part and the first electrical connection part is greater than or equal to 1 / 2 of the width of the first electrical connection part.

2. The back-contact photovoltaic module according to claim 1, characterized in that, The width of the second gate segment in the second direction is 200μm~250μm, and the second direction intersects with the first direction.

3. The back-contact photovoltaic module according to claim 1, characterized in that, Along the first direction, the length of the second grid line segment is 20mm~25mm.

4. The back-contact photovoltaic module according to claim 1, characterized in that, The back-contact photovoltaic module further includes a solder strip located on the surface of a plurality of first electrical connections away from the second grid segment. Along the thickness direction, the solder strip overlaps with the second grid segment. The fixing part is also located on at least one side of the solder strip, which is one of two opposing surfaces of the solder strip in a second direction. The thickness of the fixing part in the second direction is 100μm~150μm, and the second direction intersects with the first direction.

5. The back-contact photovoltaic module according to claim 1, characterized in that, The maximum distance between the fixing part located at the edge of the target and the edge line of the target edge is less than or equal to 10 mm, and the target edge is the first edge or the second edge.

6. The back-contact photovoltaic module according to claim 1, characterized in that, One of the second grid segments corresponds to one or two of the fixing parts.

7. The back-contact photovoltaic module according to any one of claims 1 to 6, characterized in that, The back-contact photovoltaic module further includes a first sub-grid line and a second sub-grid line alternately spaced along the first direction at the first edge, the middle region, and the second edge. The first sub-grid line and the second sub-grid line have opposite polarities. The first sub-grid line and the second sub-grid line extend along a second direction, which intersects the first direction. The back-contact photovoltaic module further includes: Multiple second electrical connections are arranged at intervals along the first direction on the surface of the first sub-grid line or the second sub-grid line away from the battery body.

8. The back-contact photovoltaic module according to any one of claims 1 to 6, characterized in that, The cross-sectional shape of the second grid segment includes at least one of the following: rectangular, elliptical, circular, trapezoidal, or irregular polygonal, and the cross-section of the second grid segment is perpendicular to the thickness direction of the back contact battery.

9. The back-contact photovoltaic module according to any one of claims 1 to 6, characterized in that, The cross-sectional shape of the first electrical connection includes at least one of the following: rectangular, elliptical, circular, trapezoidal, or irregular polygonal, and the cross-section of the first electrical connection is perpendicular to the thickness direction of the back contact battery.

10. The back-contact photovoltaic module according to any one of claims 1 to 6, characterized in that, In the first direction, the distance between the fixing part and the first electrical connection part is less than or equal to the width of the first electrical connection part.

11. The back-contact photovoltaic module according to any one of claims 1 to 6, characterized in that, The second gate line segment located at the first edge and the second edge is offset along the middle area.

12. The back-contact photovoltaic module according to claim 4, characterized in that, The fixing part is also located on the surface of the welding strip away from the battery body.

Images