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, a plurality of first grid lines 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 first grid lines extend along the second direction and are arranged on the first edge, the middle area and the second edge at intervals along the first direction, and the plurality of second grid line segments intersect with part of the first grid lines and are located on the first edge and the second edge; the plurality of welding strips are positioned on the back surface and cover the second grid line segments; the plurality of first electric connection parts are arranged between the welding strips and the second grid line segments at intervals in the first direction and are in contact with the welding strips and the first grid lines respectively; the fixing parts are located on the first edge and the second edge, and the fixing parts and the first electric connection parts are not overlapped in the thickness direction of the back contact battery. The problem that the welding reliability of the back contact photovoltaic module is poor is solved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaics, and in particular to a back-contact photovoltaic module. Background Art

[0002] Currently, back-contact (BC) PV modules are attracting widespread attention in PV module manufacturing due to their high efficiency and excellent performance. However, BC PV modules currently suffer from poor soldering reliability. Summary of the Invention

[0003] The embodiments of the present application provide a back-contact photovoltaic module, which at least solves the problem of poor welding reliability of the back-contact photovoltaic module.

[0004] According to some embodiments of the present application, on the one hand, the embodiments of the present application provide a back-contact photovoltaic module, comprising: a back-contact cell, comprising a cell body, a plurality of first grid lines and a plurality of second grid line segments, the cell body having a relative front and back, the back side comprising a first edge, a middle area and a second edge arranged in sequence along a first direction, a plurality of the first grid lines extending along a second direction and arranged at intervals along the first direction at the first edge, the middle area and the second edge, a plurality of the second grid line segments intersecting with part of the first grid lines and located at the first edge and the second edge, the first direction intersecting with the second direction; a plurality of welding strips located on the back side and covering the second grid line segments; a plurality of first electrical connection portions arranged at intervals along the first direction between the welding strips and the second grid line segments, and contacting the welding strips and the second grid line segments respectively; a fixing portion located at the first edge and the second edge, for fixing the welding strips to the back-contact cell, and the fixing portion does not overlap with the first electrical connection portion along the thickness direction of the back-contact cell.

[0005] In some embodiments, in the first direction, a minimum distance between the fixing portion and the first electrical connection portion is greater than or equal to 1 / 2 of a width of the first electrical connection portion.

[0006] In some embodiments, a width of the second gate line segment in the second direction is 200 μm-250 μm.

[0007] In some embodiments, along the first direction, the length of the second gate line segment is 20 mm to 25 mm.

[0008] In some embodiments, the fixing portion is further located on at least one side of the soldering strip, where the side is one of two opposite surfaces of the soldering strip in the second direction, and the thickness of the fixing portion in the second direction is 100 μm to 150 μm.

[0009] In some embodiments, a maximum distance between the fixing portion located at a target edge and an 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.

[0010] In some embodiments, one second gate line segment corresponds to one or two fixed portions.

[0011] In some embodiments, the plurality of first grid lines include first secondary grid lines and second secondary grid lines alternately spaced along the first direction, and the polarities of the first secondary grid lines and the second secondary grid lines are opposite. The back-contact photovoltaic module also includes: a plurality of second electrical connection parts, which are arranged at intervals along the first direction between the first secondary grid lines or the second secondary grid lines and the welding strips, and are in contact with the welding strips and the first secondary grid lines or the second secondary grid lines, respectively.

[0012] In some embodiments, the cross-sectional shape of the second gridline segment includes at least one of the following: rectangle, ellipse, circle, trapezoid, irregular polygon, and the cross-sectional shape of the second gridline segment is perpendicular to the thickness direction of the back contact battery.

[0013] In some embodiments, the cross-sectional shape of the first electrical connection portion includes at least one of the following: rectangle, ellipse, circle, trapezoid, irregular polygon, and the cross-sectional shape of the first electrical connection portion is perpendicular to the thickness direction of the back contact battery.

[0014] The technical solution provided by the embodiments of the present application has at least the following advantages: in the back-contact photovoltaic module of the present application, the fixing part is arranged 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, so that the fixing part and the first electrical connection part are arranged at intervals in the first direction. In this way, the fixing part can not only fix the welding strip, but also avoid the fixing part from penetrating into the first electrical connection part before curing, which can easily cause the problem of cold welding between the first electrical connection part and the welding strip after the lamination process, thereby ensuring that the welding effect of the back-contact battery is better and the reliability is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] One or more embodiments are exemplified by the figures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise stated, the figures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present application or the technical solutions in the traditional technology, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1This is an EL (Electroluminescence Test) image of an existing back-contact photovoltaic module;

[0017] Figure 2 A top view of a back-contact photovoltaic module provided in one embodiment of the present application;

[0018] Figure 3 A side view of a back-contact photovoltaic module provided in one embodiment of the present application;

[0019] Figure 4 This is a schematic diagram of the three-dimensional structure of a back-contact photovoltaic module provided in one embodiment of the present application;

[0020] Figure 5 This is an EL image of a back-contact photovoltaic module provided in one embodiment of the present application.

[0021] The above drawings include the following reference numerals:

[0022] 10. Battery body; 11. First grid line; 111. First secondary grid line; 112. Second secondary grid line; 12. Second grid line segment; 13. First edge; 14. Middle area; 15. Second edge; 16. Welding strip; 17. First electrical connection part; 18. Fixing part; 19. First soldering pad; 20. Second soldering pad; 21. Second electrical connection part; 22. Adhesive film. DETAILED DESCRIPTION

[0023] From the background technology, we can know that the current back-contact photovoltaic modules use glue dispensing and curing to fix the solder ribbon and the battery cell, and then use a lamination process to achieve welding of the solder ribbon and the battery cell. After glue dispensing, UV glue can easily penetrate between the solder ribbon and the solder paste, causing a cold solder joint between the solder ribbon and the solder paste, resulting in poor welding of the back-contact photovoltaic module. Figure 1 The test image of the back contact photovoltaic module with poor soldering after EL test is shown as an example. Figure 1 As shown, there is obvious blackening at the edge of the back-contact photovoltaic module.

[0024] In order to solve the technical problem, an embodiment of the present application provides a back-contact photovoltaic module, comprising: a back-contact cell, comprising a cell body, a plurality of first grid lines and a plurality of second grid line segments, the cell body having a relative front and back side, the back side comprising a first edge, a middle area and a second edge arranged in sequence along a first direction, a plurality of the first grid lines extending along a second direction and arranged at intervals along the first direction at the first edge, the middle area and the second edge, a plurality of the second grid line segments intersecting with part of the first grid lines and located at the first edge and the second edge, the first direction intersecting with the second direction; a plurality of welding strips located on the back side and covering the second grid line segments; a plurality of first electrical connection parts arranged at intervals along the first direction between the welding strips and the second grid line segments, and contacting the welding strips and the second grid line segments respectively; a fixing part located at the first edge and the second edge, for fixing the welding strips to the back-contact cell, and the fixing part does not overlap with the first electrical connection part along the thickness direction of the back-contact cell.

[0025] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0026] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0027] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0028] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0029] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0030] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and they can refer to internal connectivity between two components or interaction between two components. Those skilled in the art can understand the specific meanings of these terms in the embodiments of the present application based on specific circumstances.

[0031] In the accompanying drawings corresponding to the embodiments of the present application, the thickness and area of ​​the layers are exaggerated for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) as being on another component or on the surface of another component, the component may be "directly" located on the surface of the other component, or a third component may be present between the two components. Conversely, when describing a component as being on the surface of another component or as being formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as being "substantially" 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.

[0032] In the description of the embodiments of this application, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, 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 can be present between them. In addition, when a component such as a layer, film, region, or plate is "directly on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it means that no other components are located between them.

[0033] The terms used herein in the description of the various embodiments are intended only to describe the specific embodiments and are not intended to be limiting. As used in the description of the various embodiments and the appended claims, "part" is intended to include the plural form unless the context clearly indicates otherwise. A component includes a layer, film, region, or plate.

[0034] The following detailed description of the various embodiments of the present application is provided in conjunction with the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments of the present application to facilitate a better understanding of the present application. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0035] On the one hand, the embodiment of the present 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:

[0036] A back-contact battery includes a battery body 10, a plurality of first busbars 11, and a plurality of second busbar segments 12. The battery body has a front surface and a back surface opposite each other. The back surface includes a first edge 13, a middle area 14, and a second edge 15 sequentially arranged along a first direction. The plurality of first busbars 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 busbar segments 12 intersect with a portion of the first busbars 11 and are located at the first edge 13 and the second edge 15. The first direction intersects the second direction.

[0037] 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 gate line 11 is arranged at the first edge 13, the middle area 14 and the second edge 15, and the second gate line segment 12 is arranged at the first edge 13 and the second edge 15, each second gate line segment 12 only intersects with a portion of the first gate line 11, thereby achieving electrical contact between the second gate line segment 12 and this portion of the first gate line 11. Optionally, a plurality of the second gate line segments 12 extend along the first direction and are spaced apart along the second direction, and the length of the first gate line 11 in the second direction is greater than the length of the second gate line segment 12 in the first direction. Optionally, the first direction is perpendicular to the second direction.

[0038] a plurality of solder strips 16 , located on the back surface and covering the second gate line segments 12 ;

[0039] Optionally, the plurality of welding strips 16 extend along the first direction and are arranged at intervals along the second direction.

[0040] a plurality of first electrical connection portions 17 , arranged at intervals between the soldering ribbon 16 and the second gate line segment 12 along the first direction, and contacting the soldering ribbon 16 and the second gate line segment 12 respectively;

[0041] Specifically, the first electrical connection portion 17 is used to electrically connect the welding ribbon 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 the first gate line 11 and the second gate line segment 12 respectively.

[0042] The fixing portion 18 is located at the first edge 13 and the second edge 15 and is used to fix the soldering ribbon 16 to the back contact battery. Along the thickness direction of the back contact battery, the fixing portion 18 does not overlap with the first electrical connection portion 17.

[0043] Specifically, the orthographic projection of the fixing portion 18 on the battery body 10 and the orthographic projection of the first electrical connection portion 17 on the battery body 10 are arranged alternately without overlap. The fixing portion 18 is used to form a stable connection between the welding ribbon 16 and the second gate line segment 12.

[0044] Through the described embodiment, the fixing part is arranged 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, so that the fixing part and the first electrical connection part are arranged at intervals in the first direction. In this way, the fixing part can not only fix the welding strip, but also avoid the fixing part from penetrating into the first electrical connection part before curing, which can easily cause the problem of cold welding between the first electrical connection part and the welding strip after the lamination process, thereby ensuring that the welding effect of the back contact battery is better and the reliability is higher.

[0045] Specifically, the welding strip 16 covers the second gate line segment 12, which may mean that the welding strip 16 partially covers the second gate line segment 12, that is, the welding strip 16 covers part of the second gate line segment 12; it may also mean that the welding strip 16 completely covers the second gate line segment 12, that is, the welding strip 16 covers the entire second gate line segment 12.

[0046] In actual applications, the back-contact cell in this application can be a whole-piece structure obtained by cutting a silicon rod, or it can be an n-piece structure formed by cutting the whole-piece structure, where n ≥ 2 and n is an integer. For example, when n = 2, the back-contact cell is a two-piece structure; when n = 3, the back-contact cell is a three-piece structure; and when n = 4, the back-contact cell is a four-piece structure.

[0047] Alternatively, as Figure 2As shown, the second gate segment 12 is only provided at the first edge 13 and the second edge 15, and not in the middle region 14. This reduces the material usage of the second gate segment 12. Furthermore, by directing the current from the front and rear edge regions of the back-contact cell via the second gate segment 12, the ability of the soldering ribbon 16 to collect current from the back-contact cell is enhanced, solving the problem of low edge current collection efficiency. Furthermore, the second gate segment 12 ensures a larger contact area between the soldering ribbon 16 and the back-contact cell, increasing the soldering tension of the soldering ribbon 16 in the edge regions and further reducing the risk of solder joint failure.

[0048] Optionally, the second gate line segments 12 located at the first edge 13 and the second edge 15 can be symmetrically arranged along the middle region 14, with one welding 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 welding 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.

[0049] In some embodiments, the back-contact photovoltaic module is a back-contact photovoltaic module without a busbar. In other embodiments, the back-contact photovoltaic module may also be a back-contact photovoltaic module with a busbar.

[0050] In actual application, 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.

[0051] In some embodiments, the material of the fixing portion 18 includes UV glue. For example, the fixing portion 18 can be UV glue. UV glue as the material of the fixing portion 18 has a fast curing speed.

[0052] Of course, the material of the fixing portion 18 is not limited to the UV adhesive, and may also be silicone adhesive, epoxy resin adhesive, etc.

[0053] In one optional embodiment, the cross-sectional shape of the second gate segment 12 includes at least one of the following: rectangular, elliptical, circular, trapezoidal, or irregular polygonal, and the cross-sectional shape of the second gate segment 12 is perpendicular to the thickness direction of the back-contact cell. The cross-sectional shape of the second gate segment 12 is designed 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, thereby improving current collection efficiency.

[0054] In some other embodiments, the material of the first electrical connection portion 17 includes tin. For example, the first electrical connection portion 17 can be tin paste. Tin paste has good electrical conductivity and welding performance.

[0055] Of course, the material of the first electrical connection portion 17 is not limited to the aforementioned tin, and may also be lead-free solder alloy, silver-based conductive adhesive, copper-based conductive adhesive, nickel-based conductive adhesive, etc.

[0056] In another optional solution, the cross-sectional shape of the first electrical connection portion 17 includes at least one of the following: rectangle, ellipse, circle, trapezoid, irregular polygon, and the cross-sectional shape 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 an important influence on the current transmission efficiency. By selecting a suitable cross-sectional shape, such as rectangle, ellipse, circle, trapezoid or irregular polygon, the contact area and current distribution of the electrical connection can be optimized, and the contact resistance can be reduced. This design solves the problem of electrical connection optimization, including but not limited to improving the electrical performance and reliability of components in components with complex circuit layouts by adjusting the cross-sectional shape of the first electrical connection portion 17.

[0057] In some embodiments, in the first direction, the minimum distance between the fixing portion 18 and the first electrical connection portion 17 is greater than or equal to 1 / 2 of the width of the first electrical connection portion 17. By controlling the spacing between the fixing portion 18 and the first connection portion in the first direction, sufficient space is ensured between the two, further preventing the fixing portion 18 from flowing into the first electrical connection portion 17 before solidification, causing glue seepage and affecting the welding effect between the first electrical connection portion 17 and the soldering ribbon 16, thereby further ensuring a good connection reliability between the first electrical connection portion 17 and the soldering ribbon 16.

[0058] Specifically, the minimum distance refers to the minimum value of the straight-line distance between the edge of the fixing portion 18 and the edge of the first electrical connection portion 17 .

[0059] In other embodiments, in the first direction, the minimum distance between the fixing portion 18 and the first electrical connection portion 17 is less than or equal to the width of the first electrical connection portion 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.

[0060] 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.

[0061] Specifically, the width of the second grid line segment 12 in the second direction is 200μm~250μm. For example, the width of the second grid line segment 12 in the second direction can be 200μm, 210μm, 220μm, 230μm, 240μm, or 250μm, etc. The width of the second grid line segment 12 is designed to be between 200μm and 250μm, so that the width of the second grid line segment 12 is relatively large. This ensures that the second grid line segment 12 can carry a large current and reduce resistance loss. The widened second grid line segment 12 can also provide greater pulling force, further reducing the phenomenon of cold soldering of the welding ribbon 16, thereby further improving the reliability of the back-contact photovoltaic module, and ensuring that the mechanical strength of the back-contact battery edge is high, thereby enhancing the durability of the back-contact photovoltaic module.

[0062] In some embodiments, the length of the second gate segment 12 along the first direction is 20 mm to 25 mm. For example, the length of the second gate segment 12 in the first direction can be 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, or 25 mm. Designing the length of the second gate segment 12 to be between 20 mm and 25 mm can reduce the material usage of the second gate segment 12 and improve the current collection efficiency of the edge area of ​​the back contact battery, thereby improving the current collection capability of the solder ribbon 16 in the back contact battery.

[0063] According to further embodiments of the present application, the fixing portion 18 is further located on at least one side edge of the solder ribbon 16, where the side edge is one of two opposing surfaces of the solder ribbon 16 in the second direction. The thickness of the fixing portion 18 in the second direction is between 100 μm and 150 μm. For example, the thickness of the fixing portion 18 in the second direction can be 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, or 150 μm. Positioning the fixing portion 18 on at least one side edge of the solder ribbon 16 and contacting the back of the back-contact solar cell improves the adhesion between the solder ribbon 16 and the back-contact solar cell, thereby further ensuring that the fixing portion 18 effectively secures the solder ribbon 16 and further prevents the solder ribbon 16 from loosening and shifting during the photovoltaic module manufacturing process, which could affect the performance of the back-contact photovoltaic module. Designing the thickness of the fixing portion 18 between 100 μm and 150 μm ensures both effective securing of the fixing portion 18 and an appropriate packaging space.

[0064] In some embodiments, as Figure 2 As shown, the fixing portion 18 may be located only on the side of the welding strip 16; in other embodiments, as shown Figure 4 As shown, the fixing portion 18 may be located on a side of the welding ribbon 16 and on a surface of the welding ribbon 16 away from the battery body 10 .

[0065] In some embodiments, one second gate line segment 12 corresponds to one or two fixing portions 18. One or two fixing portions 18 can fix the soldering ribbon 16 without occupying too much packaging space of the photovoltaic module, thereby ensuring high space utilization of the photovoltaic module.

[0066] Those skilled in the art can reasonably configure the number of the fixing parts 18 to ensure reliable fixing of the welding ribbon 16 . The number is not limited to one or two. For example, one second gate line segment 12 can correspond to multiple fixing parts 18 .

[0067] In a specific application, when one soldering ribbon 16 corresponds to one fixing portion 18, the fixing portion 18 is located on one side of the soldering ribbon 16. When one soldering ribbon 16 corresponds to multiple fixing portions 18, the multiple fixing portions 18 can be located on the same side of the soldering ribbon 16, or on both sides of the soldering ribbon 16. When the fixing portions 18 are located on both sides of the soldering ribbon 16, the fixing portions 18 located on both sides can be symmetrically arranged or staggered along the first direction.

[0068] In some further embodiments, the maximum distance between the fixing portion 18 located at the target edge and the edge line of the target edge is less than or equal to 10 mm, where the target edge is the first edge 13 or the second edge 15. For example, the maximum distance between the fixing portion 18 and the target edge can be 10 mm, 9 mm, 8 mm, 7 mm, or 6 mm. By providing the fixing portion 18 at the leading and trailing edges of the back contact cell and adjusting the distance between the fixing portion 18 and the edge, the fixing portion 18 secures the leading and trailing ends of the solder ribbon 16, further ensuring a better securing effect of the fixing portion 18.

[0069] Specifically, the maximum distance refers to the maximum value of the distance between the edge of the fixing portion 18 and the edge line of the target edge.

[0070] According to some further solutions of the present application, the maximum distance between the fixing portion 18 located at the target edge and the edge line of the target edge is greater than 0 mm.

[0071] In some embodiments, the plurality of first grid lines 11 include first secondary grid lines 111 and second secondary grid lines 112 alternately spaced along the first direction, the first secondary grid lines 111 and the second secondary grid lines 112 having opposite polarities, and the back-contact photovoltaic module further includes: a plurality of second electrical connection portions 21 spaced along the first direction between the first secondary grid lines 111 and the welding ribbon 16 or between the second secondary grid lines 112 and the welding ribbon 16; and the second electrical connection portions 21 are in contact with the welding ribbon 16 and the first secondary grid lines 111, respectively, or the second electrical connection portions 21 are in contact with the welding ribbon 16 and the second secondary grid lines 112, respectively. The alternately spaced first secondary grid lines 111 and the second secondary grid lines 112 enable the collection of electrons and holes in the battery and their transfer to the welding ribbon 16.

[0072] Specifically, the second electrical connection portion 21 is located in the middle area 14 and is used to electrically connect the soldering ribbon 16 to the first secondary grid line 111, or to electrically connect the soldering ribbon 16 to the second secondary grid line 112. Among the multiple soldering ribbons 16 of the present application, the polarity of some soldering ribbons 16 is the same as that of the first secondary grid line 111, and the polarity of some soldering ribbons 16 is the same as that of the second secondary grid line 112.

[0073] In addition, part of the second gate line segments 12 has the same polarity as the first auxiliary gate line 111 , and the remaining part of the second gate line segments 12 has the same polarity as the second auxiliary gate line 112 . The second gate line segments 12 with different polarities are alternately arranged along the second direction.

[0074] To ensure insulation between the solder ribbons 16 of different polarities and the first grid lines 11, in one embodiment, the back-contact cell further includes a plurality of first insulating portions (not shown) positioned between the solder ribbons 16 of different polarities and the first grid lines 11 to provide electrical insulation between the two. Of course, the first insulating portions may also be omitted. In another embodiment, the first grid lines 11 of different polarity from the solder ribbons 16 are disconnected on both sides of the solder ribbons 16.

[0075] To ensure insulation between the second gateline segments 12 of different polarities and the first gateline 11, 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 gateline segments 12 of different polarities and the first gateline 11 to achieve electrical insulation between the two. Of course, the second insulating portions may also be omitted. In another embodiment, the first gateline 11 of a different polarity than the second gateline segment 12 is disconnected on both sides of the second gateline segment 12.

[0076] Specifically, the material of the second electrical connection portion 21 includes but is not limited to solder paste, lead-free solder alloy, conductive adhesive, etc.

[0077] In some embodiments, the cross-sectional shape of the second electrical connection portion 21 includes at least one of the following: rectangle, ellipse, circle, trapezoid, and irregular polygon, and the cross-sectional shape of the second electrical connection portion 21 is perpendicular to the thickness direction of the back contact battery.

[0078] Optionally, the second electrical connection portion 21 may be made of the same material as or different from the first electrical connection portion 17 . 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 .

[0079] In some embodiments, the width of the second gate line 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 line segment 12 in the second direction may be 20 times, 22 times, 23 times, 25 times, 27 times, 29 times, 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 line segment 12 to be greater than the width of the first gate line 11, the current collection efficiency of the second gate line segment 12 can be further ensured to be higher, so that the second gate line segment 12 can extract the current of the first edge 13 and the second edge 15.

[0080] Optionally, during the preparation of the back-contact photovoltaic module, after the welding ribbon 16 is placed on the side of the first electrical connection part 17 and the second electrical connection part 21 away from the back-contact cell, the fixing part 18 is first formed on the side of the welding ribbon 16 by low-temperature dispensing technology, and then the fixing part 18 is cured, and finally, good welding between the welding ribbon 16 and the first electrical connection part 17, and between the welding ribbon 16 and the second electrical connection part 21 is achieved by lamination technology.

[0081] According to some embodiments of the present application, the back-contact photovoltaic module further includes a plurality of first soldering pads 19, which are located in the middle area 14 and spaced apart along the first direction. The first soldering 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 can be located between the first soldering pad 19 and the soldering ribbon 16. The orthographic projection of the first soldering pad 19 on the back surface is greater than or equal to the orthographic projection of the second electrical connection portion 21 on the back surface. By providing the first soldering pad 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 the two.

[0082] During the manufacturing process of the back-contact photovoltaic module, the first soldering 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 soldering pad 19 can be printed.

[0083] In addition, the back-contact photovoltaic module may further include a plurality of second soldering pads 20, with the plurality of second soldering pads 20 being located between the first edge 13 and the second edge 15. The second soldering pads 20 are also located between the second grid line segment 12 and the first electrical connection portion 17. In other words, the first electrical connection portion 17 may be located between the second soldering pads 20 and the soldering ribbon 16. The orthographic projection of the second soldering pads 20 on the back surface is greater than or equal to the orthographic projection of the first electrical connection portion 17 on the back surface. By providing the second soldering pads 20, the contact area between the first electrical connection portion 17 and the second grid line segment 12 is increased, thereby reducing the contact resistance between the first electrical connection portion 17 and the second grid line segment 12 and improving the contact quality between the two.

[0084] Similarly, during the manufacturing process of the back-contact photovoltaic module, the second pad 20 and the second grid line segment 12 can be integrally formed, or the second grid line segment 12 can be printed on the back of the back-contact cell first, and then the second pad 20 can be printed.

[0085] In actual application, 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.

[0086] like Figure 4 As shown, the back-contact photovoltaic module further includes an adhesive film 22 located on the surface of the cell body 10 , the welding ribbon 16 and the fixing portion 18 .

[0087] The test image obtained by performing EL test on the back contact photovoltaic module of this application is as follows: Figure 5 As shown, comparison Figure 1 and Figure 5 It can be clearly seen that there is no blackening phenomenon on the edge of the back-contact photovoltaic module of the present application. Compared with the prior art, the present application significantly improves the problem of cold solder joints on the edge of the back-contact photovoltaic module.

[0088] The back-contact photovoltaic module of the present application will be described in detail below with reference to specific embodiments and comparative examples.

[0089] Example 1

[0090] This embodiment provides a back-contact photovoltaic module, comprising:

[0091] A back-contact battery, comprising a battery body, a plurality of first gridlines, and a plurality of second gridline segments, the battery body having opposite front and back surfaces, the back surface comprising a first edge, a middle region, and a second edge sequentially arranged along a first direction, the plurality of first gridlines extending along a second direction and spaced apart along the first direction at the first edge, the middle region, and the second edge, the plurality of second gridline segments intersecting with some of the first gridlines and located at the first and second edges, the first direction intersecting the second direction, the width of the second gridline segments in the second direction being 220 μm, and the length of the second gridline segments being 23 mm;

[0092] a plurality of welding strips, located on the back surface and covering the second gate line segment;

[0093] a plurality of first electrical connection portions, arranged at intervals between the welding strip and the second gate line segment along the first direction, and contacting the welding strip and the second gate line segment respectively;

[0094] A fixing portion is located at the first edge and the second edge, and is used to fix the solder strip and the back contact battery. Along the thickness direction of the back contact battery, the fixing portion and the first electrical connection portion do not overlap.

[0095] Example 2

[0096] This embodiment provides a back-contact photovoltaic module. The only difference between this back-contact photovoltaic module and the embodiment 1 is that the width of the second gate line segment in the second direction is 200 μm.

[0097] Example 3

[0098] 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 gate line segment in the second direction is 250 μm.

[0099] Example 4

[0100] 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 line segment is 20 mm.

[0101] Example 5

[0102] 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 line segment is 25 mm.

[0103] Comparative Example 1

[0104] 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 gate line segment in the second direction is 150 μm.

[0105] Comparative Example 2

[0106] This embodiment provides a back-contact photovoltaic module. The only difference between this back-contact photovoltaic module and the embodiment 1 is that the width of the second gate line segment in the second direction is 300 μm.

[0107] Comparative Example 3

[0108] 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 line segment is 15 mm.

[0109] Comparative Example 4

[0110] 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 line segment is 30 mm.

[0111] Comparative Example 5

[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 gate line segment is 100 mm and the width in the second direction is 10 mm.

[0113] Performance tests were performed on the back-contact photovoltaic modules corresponding to each of the examples 1 to 5 and comparative examples 1 to 5. The test results are shown in Table 1:

[0114] Table 1

[0115] Back contact PV module number Power attenuation after TC EL head and tail cold solder ratio Example 1 0.91% 0.66% Example 2 1.45% 0.79% Example 3 0.81% 0.4% Example 4 0.94% 0.7% Example 5 0.9% 0.62% Comparative Example 1 10.32% 10.4% Comparative Example 2 0.78% 0.52% Comparative Example 3 4.5% 7.3% Comparative Example 4 0.97% 0.7% Comparative Example 5 78.35% 70.2%

[0116] The experimental data shows that the power attenuation and EL head-to-tail solder joint rate after temperature cycling (TC) in Examples 1-5 are lower than those in Comparative Examples 1, 3, and 5. This indicates that the thickened length and width of the second gate segment reduce both the power attenuation after TC and the EL head-to-tail solder joint rate. The power attenuation in Examples 1-5 can be reduced to below 3%, and the solder joint rate to below 1%, significantly reducing the risk of post-TC solder joints. Furthermore, compared to Comparative Examples 2 and 4, the overall footprint of the second gate segment in Examples 1-5 is smaller, ensuring both the reliability and space utilization of the back-contact cell.

[0117] From the above description, it can be seen that the embodiments described in this application achieve the following technical effects:

[0118] In the back-contact photovoltaic module of the present application, the fixing part is arranged 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, so that the fixing part and the first electrical connection part are arranged at intervals in the first direction. In this way, the fixing part can not only fix the welding strip, but also avoid the fixing part from penetrating into the first electrical connection part before curing, which can easily cause the problem of cold welding between the first electrical connection part and the welding strip after the lamination process, thereby ensuring that the welding effect of the back-contact battery is better and the reliability is higher.

[0119] Those skilled in the art will understand that the various embodiments described are specific examples for implementing the present application, and that in actual applications, various changes in form and detail may be made thereto without departing from the spirit and scope of the present application. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined in the claims.

Claims

1. A back contact photovoltaic module, characterized in that: include: A back-contact battery, comprising a battery body, a plurality of first gridlines, and a plurality of second gridline segments, wherein the battery body has a front surface and a back surface opposite each other, the back surface comprising a first edge, a middle region, and a second edge sequentially arranged along a first direction, the plurality of first gridlines extending along a second direction and spaced apart along the first direction at the first edge, the middle region, and the second edge, the plurality of second gridline segments intersecting with a portion of the first gridlines and located at the first edge and the second edge, the first direction intersecting the second direction; a plurality of welding strips, located on the back surface and covering the second gate line segment; a plurality of first electrical connection portions, arranged at intervals between the welding strip and the second gate line segment along the first direction, and contacting the welding strip and the second gate line segment respectively; A fixing portion is located at the first edge and the second edge, and is used to fix the solder strip and the back contact battery. Along the thickness direction of the back contact battery, the fixing portion and the first electrical connection portion do not overlap.

2. The back contact photovoltaic module according to claim 1, characterized in that: In the first direction, a minimum distance between the fixing portion and the first electrical connection portion is greater than or equal to 1 / 2 of a width of the first electrical connection portion.

3. The back contact photovoltaic module according to claim 1, characterized in that: The width of the second gate line segment in the second direction is 200 μm to 250 μm.

4. The back contact photovoltaic module according to claim 1, characterized in that: Along the first direction, the length of the second gate line segment is 20 mm to 25 mm.

5. The back contact photovoltaic module according to claim 1, characterized in that: The fixing portion is further located on at least one side of the soldering strip, where the side is one of two opposite surfaces of the soldering strip in the second direction. The thickness of the fixing portion in the second direction is 100 μm to 150 μm.

6. The back contact photovoltaic module according to claim 1, characterized in that: A maximum distance between the fixing portion located at a target edge and an 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.

7. The back contact photovoltaic module according to claim 1, characterized in that: One second gate line segment corresponds to one or two fixed parts.

8. The back-contact photovoltaic module according to any one of claims 1 to 7, characterized in that: The plurality of first grid lines include first secondary grid lines and second secondary grid lines alternately arranged along the first direction, wherein the first secondary grid lines and the second secondary grid lines have opposite polarities, and the back-contact photovoltaic module further includes: A plurality of second electrical connection portions are arranged at intervals along the first direction between the first secondary grid line or the second secondary grid line and the welding strip, and are in contact with the welding strip and the first secondary grid line or the second secondary grid line respectively.

9. The back-contact photovoltaic module according to any one of claims 1 to 7, characterized in that: The cross-sectional shape of the second gridline segment includes at least one of the following: rectangle, ellipse, circle, trapezoid, and irregular polygon, and the cross-sectional shape of the second gridline segment 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 7, characterized in that: The cross-sectional shape of the first electrical connection portion includes at least one of the following: rectangle, ellipse, circle, trapezoid, and irregular polygon, and the cross-sectional shape of the first electrical connection portion is perpendicular to the thickness direction of the back contact battery.

Images