Photovoltaic module and manufacturing method thereof

Abstract

The invention relates to the technical field of photovoltaic, and provides a photovoltaic module and a manufacturing method thereof, which are at least beneficial to improving the efficiency and yield of the photovoltaic module. The photovoltaic module comprises at least two battery strings arranged along a second direction, each battery string comprises a plurality of back contact batteries which are sequentially arranged along a first direction, the first back contact battery and the tail back contact battery in the battery strings are end batteries, and the back contact battery between the end batteries is an intermediate battery; the two ends of the first welding strip are located on the surfaces of the two adjacent back contact batteries in the first direction respectively; the first covering film covers the surface of the middle battery; the second welding strip is positioned on the surface of the end battery; the second covering film covers the surface of the end battery; the first bus bars are located on the middle battery and located on the side, away from the back contact battery, of the first covering film, and the multiple second welding strips are welded to the same first bus bar; and the end parts of the first bus bars of the two battery strings are electrically connected through welding.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and particularly to a photovoltaic module and a manufacturing method thereof. Background Art

[0002] In photovoltaic technology, the most prominent feature of a back contact (BC) cell is that both the PN junction and the contact metal are located on the back surface of the BC cell. The front surface of the BC cell completely avoids the occlusion of the metal grid line electrodes, can maximize the utilization of incident light, reduce optical losses, and has a higher short-circuit current. In a photovoltaic module, multiple back contact cells form a battery string through steps such as series soldering or module full-plate soldering, lamination, and encapsulation, and two battery strings are connected by busbars.

[0003] In the welding process of back contact cells, since grid lines of different polarities in the back contact cells are all located on the same side surface, the corresponding solder tapes need to be welded to the same side surface of the back contact cells. After high-temperature welding, the back contact cells are prone to warping problems, resulting in a decrease in the yield of photovoltaic modules. In addition, in the process of connecting busbars, the busbars are usually installed at the edges of the back contact cells. Therefore, a certain space needs to be reserved at the edges of the back contact cells to place the busbars, and the reserved space reduces the light-receiving area of the photovoltaic module, resulting in a decrease in the efficiency of the photovoltaic module.

[0004] Therefore, how to improve the yield and efficiency of back contact cell photovoltaic modules has become an urgent problem to be solved. Summary of the Invention

[0005] Embodiments of this application provide a photovoltaic module and a manufacturing method thereof, which are at least beneficial to improving the efficiency and yield of the photovoltaic module.

[0006] According to some embodiments of the present application, on the one hand, an embodiment of the present application provides a photovoltaic module, including: a plurality of battery strings, each battery string including: a back-contact battery, a first solder tape, a first film, a second solder tape, a second film, and a first bus bar; a plurality of back-contact batteries are arranged in sequence along a first direction, and the back-contact batteries at the first and last positions in the battery string are end batteries, and the back-contact batteries located between the end batteries are intermediate batteries; both ends of the first solder tape are respectively located on the surfaces of two adjacent back-contact batteries along the first direction; the first film is located on the side of the first solder tape away from the intermediate battery and covers the surface of the intermediate battery; the second solder tape is located on the surface of at least one end battery; the second film is located on the side of the first solder tape and the second solder tape away from the end battery and covers the surface of the end battery; the first bus bar is located on the intermediate battery adjacent to the end battery, and the first bus bar is located on the side of the first film away from the back-contact battery, and the ends of a plurality of second solder tapes close to the intermediate battery are welded to the same first bus bar; at least two battery strings are arranged along a second direction, and the ends of the first bus bars of the two battery strings are electrically connected by welding.

[0007] In some embodiments, the first bus bar includes a first body portion and a first welding portion. In a direction perpendicular to the surface of the back-contact battery, the thickness of the first welding portion is less than the thickness of the first body portion, and the first welding portion is used for welding and connecting the first bus bar corresponding to one battery string and the first bus bar corresponding to another battery string.

[0008] In some embodiments, the first welding portions of the first bus bars corresponding to two battery strings are welded to the same connecting piece.

[0009] In some embodiments, the first welding portions of the first bus bars corresponding to two battery strings are directly welded.

[0010] In some embodiments, at least two battery strings are arranged along the first direction, and the end batteries without the second solder tape in the two battery strings are arranged adjacent to each other; the photovoltaic module further includes: a third solder tape and a second bus bar, one end of the third solder tape is located on the surface of the end battery of one battery string, and the other end is located on the surface of the end battery of another battery string; the second bus bar is located on the intermediate battery adjacent to the end battery, and the second bus bar is located on the side of the first film away from the back-contact battery, and the ends of a plurality of third solder tapes are welded to the same second bus bar; the second film is also located on the side of the third solder tape away from the end battery and covers the surface of the end battery.

[0011] In some embodiments, it further includes: an isolation film, and the isolation film is located between the first bus bar and the first film.

[0012] In some embodiments, the surface of the isolation film facing the first film has an adhesive layer, and / or the surface of the isolation film facing the first bus bar has an adhesive layer.

[0013] In some embodiments, the same first film covers the surfaces of multiple intermediate cells.

[0014] According to some embodiments of the present application, on the other hand, an embodiment of the present application further provides a manufacturing method of a photovoltaic module, including: preparing a battery string, and the step of preparing the battery string includes: providing back-contact cells, arranging a plurality of back-contact cells in sequence along a first direction, the back-contact cells arranged at the first and the last are end cells, and the back-contact cells located between the end cells are intermediate cells; laying a first solder ribbon, both ends of the first solder ribbon are respectively located on the surfaces of two adjacent back-contact cells along the first direction; laying a first film, the first film is located on the side of the first solder ribbon away from the intermediate cells and covers the surfaces of the intermediate cells; laying a second solder ribbon and a first bus bar, the second solder ribbon is located on the surface of at least one end cell, the first bus bar is located on the intermediate cell adjacent to the end cell, and the first bus bar is located on the side of the first film away from the back-contact cells, and the ends of a plurality of second solder ribbons close to the intermediate cells are welded to the same first bus bar; laying a second film, the second film is located on the side of the first solder ribbon and the second solder ribbon away from the end cells and covers the surfaces of the end cells; connecting a plurality of battery strings, at least two battery strings are arranged along a second direction, and the ends of the first bus bars of the two battery strings are connected by welding.

[0015] In some embodiments, before laying the second solder ribbon and the first bus bar, it includes: laying an isolation film on the first film corresponding to the intermediate cell adjacent to the end cell, and the isolation film is located on the side of the first film adjacent to the end cell; laying the second solder ribbon and the first bus bar includes: laying the first bus bar on the isolation film.

[0016] The technical solutions provided by the embodiments of the present application have at least the following advantages:

[0017] In the photovoltaic module provided by the embodiment of the present application, adjacent back-contact cells are connected by a first solder tape to form a battery string, and the end cells at the first or the last are led out to the first bus bar through a second solder tape. The first film is used to fix the position of the first solder tape on the intermediate cells, and the second film is used to fix the positions of the first solder tape and the second solder tape on the end cells, so as to avoid the problem that the back-contact cells are warped due to high-temperature soldering, which is beneficial to improving the yield of the photovoltaic module. The first bus bar is located on the intermediate cell adjacent to the end cell, and the first bus bar is located on the side of the first film away from the back-contact cell. In this way, the first film can be used to isolate the intermediate cell from the first bus bar to avoid the problem of leakage between the first bus bar and the solder tapes with different polarities on the intermediate cell; at the same time, the first bus bar is located on the intermediate cell, which is beneficial to hiding the first bus bar behind the back-contact cell, avoiding the first bus bar occupying the effective area of the photovoltaic module, and thus beneficial to improving the light conversion efficiency of the photovoltaic module. The ends of the first bus bars corresponding to two battery strings arranged in the second direction are electrically connected by soldering. In this way, in the preparation step of the battery string, the first bus bar can have been soldered to the second solder tape; during the series connection process of the battery strings, soldering the first bus bars of different battery strings can achieve the series connection of multiple battery strings, thus improving the manufacturing efficiency of the photovoltaic module. Description of the Drawings

[0018] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not limit the embodiments unless otherwise stated. The figures in the drawings do not constitute a proportional limitation; in order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the following-described drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 It is a schematic structural diagram of the photovoltaic module provided by the embodiment of the present application;

[0020] Figure 2 is Figure 1 A schematic cross-sectional structure diagram along the AA1 direction;

[0021] Figure 3 is Figure 1 Another schematic cross-sectional structure diagram along the AA1 direction;

[0022] Figure 4 It is a schematic structural diagram of another photovoltaic module provided by the embodiment of the present application;

[0023] Figures 5 to 9Schematic structural diagrams corresponding to the respective steps of a manufacturing method for a photovoltaic module provided by an embodiment of the present application.

[0024] Explanation of reference numerals:

[0025] 10. Battery string; 100. Back-contact battery; 101. End battery; 102. Intermediate battery; 111. First solder tape; 112. Second solder tape; 113. Third solder tape; 121. First film coating; 122. Second film coating; 131. First bus bar; 132. Second bus bar; 1311. First welding portion; 1312. First body portion; 1313. Connecting piece. Detailed implementation manners

[0026] As can be seen from the background art, how to improve the yield and efficiency of back-contact battery photovoltaic modules has become an urgent problem to be solved.

[0027] An embodiment of the present application provides a photovoltaic module and a manufacturing method thereof, which are at least beneficial to improving the efficiency and yield of the photovoltaic module.

[0028] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features.

[0029] In the description of the embodiments of the present application, the meaning of "a plurality of" is more than two, unless otherwise specifically and clearly defined.

[0030] Referring to "embodiment" in this article means that the specific features, structures or characteristics described in combination with the embodiment may be included in at least one embodiment of the present application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0031] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: the existence of A, the simultaneous existence of A and B, and the existence of B. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0032] In the description of the embodiments of the present application, technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the embodiments of the present application.

[0033] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "install", "connect", "couple", "fix", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0034] In the drawings corresponding to the embodiments of the present application, for better understanding and convenience of description, the thickness and area of the layers are enlarged. When describing that one component is on or on the surface of another component, the component can be "directly" on the surface of the other component, or there can be a third component between the two components. On the contrary, when describing that one component is on the surface of another component or one component surface forms or is provided with another component, it means that there is no third component between the two components. In addition, when describing that one component is "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 on a partial edge of the entire surface.

[0035] In the description of the embodiments of the present application, when a certain component "includes" another component, unless otherwise stated, other components are not excluded, and other components may further be included.

[0036] The terms used in the description of the various embodiments herein are only for describing specific embodiments and are not intended to be limiting. As used in the description of the various embodiments and the appended claims, "component" is also intended to include the plural form unless the context clearly indicates otherwise.

[0037] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present application, many technical details are provided to help readers better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0038] Figure 1 It is a schematic structural diagram of a photovoltaic module provided by an embodiment of the present application.

[0039] Referring to Figure 1 , an embodiment of the present application provides a photovoltaic module on the one hand, including: a plurality of battery strings 10, and the battery string 10 includes: back contact batteries 100, first solder tapes 111, first encapsulation films 121, second solder tapes 112, second encapsulation films 122, and first busbars 131.

[0040] A plurality of back contact batteries 100 are arranged in sequence along the first direction X. The back contact batteries 100 at the first and last positions in the battery string 10 are end batteries 101, and the back contact batteries 100 between the end batteries 101 are intermediate batteries 102.

[0041] Both ends of the first solder tape 111 are respectively located on the surfaces of two adjacent back contact batteries 100 along the first direction X. The first solder tape 111 is used to connect two adjacent back contact batteries 100. Specifically, one end of the first solder tape 111 is used to connect one of the positive grid lines or negative grid lines of a back contact battery 100, and the other end is used to connect the other of the positive grid lines or negative grid lines of another back contact battery 100 to connect the two back contact batteries 100 in series.

[0042] The first encapsulation film 121 is located on the side of the first solder tape 111 away from the intermediate battery 102 and covers the surface of the intermediate battery 102. The first encapsulation film 121 is used to fix the position of the first solder tape 111 on the intermediate battery 102.

[0043] The second solder tape 112 is located on the surface of at least one end battery 101. The second solder tape 112 is used to be welded to the first busbar 131 to lead the current on the back contact battery 100 to the first busbar 131.

[0044] The second encapsulation film 122 is located on the side of the first solder tape 111 and the second solder tape 112 away from the end battery 101 and covers the surface of the end battery 101. The second encapsulation film 122 is used to fix the first solder tape 111 and the second solder tape 112 on the end battery 101.

[0045] The first bus bar 131 is located on the intermediate cell 102 adjacent to the end cell 101, and the first bus bar 131 is located on the side of the first coating film 121 away from the back contact cell 100. A plurality of second solder tapes 112 are welded to the same first bus bar 131 near the ends of the intermediate cell 102.

[0046] At least two cell strings 10 are arranged along the second direction Y, and the ends of the first bus bars 131 of the two cell strings 10 are electrically connected by welding.

[0047] In the photovoltaic module provided by the embodiment of the present application, adjacent back contact cells 100 are connected by the first solder tape 111 to form a cell string 10. The end cell 101 at the first or the last position leads out current to the first bus bar 131 through the second solder tape 112. The first coating film 121 is used to fix the position of the first solder tape 111 on the intermediate cell 102, and the second coating film 122 is used to fix the positions of the first solder tape 111 and the second solder tape 112 on the end cell 101. In this way, the problem that the back contact cell 100 is warped due to high-temperature welding can be avoided, which is beneficial to improving the yield of the photovoltaic module. The first bus bar 131 is located on the intermediate cell 102 adjacent to the end cell 101, and the first bus bar 131 is located on the side of the first coating film 121 away from the back contact cell 100. In this way, the first coating film 121 can be used to isolate the intermediate cell 102 from the first bus bar 131 to avoid the problem of leakage between the first bus bar 131 and the solder tapes with different polarities on the intermediate cell 102. At the same time, the first bus bar 131 is located on the intermediate cell 102, which is beneficial to hiding the first bus bar 131 on the back of the back contact cell 100, avoiding the first bus bar 131 occupying the effective area of the photovoltaic module, and thus being beneficial to improving the light conversion efficiency of the photovoltaic module. The ends of the first bus bars 131 corresponding to the two cell strings 10 arranged along the second direction Y are electrically connected by welding. In this way, in the preparation step of the cell string 10, the first bus bar 131 can have been welded to the second solder tape 112. During the connection process of the cell strings 10, the first bus bars 131 of different cell strings 10 are welded to realize the connection of multiple cell strings 10, thereby improving the manufacturing efficiency of the photovoltaic module.

[0048] In some embodiments, the back-contact battery 100 may be an IBC battery (Interdigitated Back Contact battery), an HPBC battery (Hybrid Passivated Back Contact battery), a TBC battery that stacks TOPCon (Tunnel Oxide Passivated Contact battery) technology and IBC technology, or an HBC battery that stacks HIT / HJT (Heterojunction Technology battery) technology and IBC technology. Of course, it may also be other types of back-contact batteries.

[0049] In some embodiments, both the first solder tape 111 and the second solder tape 112 may be low-temperature solder tapes, that is, the melting point temperature of the solder tape does not exceed 175°C. In this way, the subsequent lamination process can be used to alloy the first solder tape 111 and the second solder tape 112 with the metal grid electrodes on the back-contact battery 100, thereby making the transmission efficiency of the first solder tape 111 and the second solder tape 112 with the back-contact battery 100 relatively high.

[0050] Figure 2 is Figure 1 A schematic cross-sectional structure diagram along the AA1 direction; Figure 3 is Figure 1 Another schematic cross-sectional structure diagram along the AA1 direction.

[0051] Refer to Figure 2 and Figure 3 As shown in, the first bus bar 131 may include a first body portion 1312 and a first welding portion 1311. The first welding portion 1311 is used to weld and connect the first bus bar 131 corresponding to one battery string 10 with the first bus bar 131 corresponding to another battery string 10.

[0052] Refer to Figure 2 As shown in, in some embodiments, the first welding portions 1311 of the first bus bars 131 corresponding to two battery strings 10 are directly welded. Or, refer to Figure 3 As shown in, in some other embodiments, the first welding portions 1311 of the first bus bars 131 corresponding to two battery strings 10 are both welded to the same connecting piece 1313, thereby achieving electrical connection.

[0053] Refer to Figure 2 and Figure 3, in some embodiments, in a direction perpendicular to the surface of the back-contact battery 100, the thickness of the first welding portion 1311 is less than the thickness of the first body portion 1312. In this way, regardless of whether the first welding portions 1311 of the first busbars 131 corresponding to the two battery strings 10 are directly welded or welded through the connecting piece 1313, the total thickness of the position corresponding to the first welding portion 1311 after welding can be less than or equal to the thickness of the first body portion 1312, thereby avoiding the problem that the back-contact battery 100 is fragmented due to stress concentration caused by excessive thickness after welding at the position corresponding to the first welding portion 1311.

[0054] In other embodiments, the thickness of the first welding portion may also be greater than or equal to the thickness of the first body portion.

[0055] Reference Figure 2 And Figure 3 , in a direction perpendicular to the surface of the back-contact battery 100, the thickness of the first coating film 121 is greater than the height of the first solder tape 111. In this way, the first coating film 121 can wrap the first solder tape 111, and the surface of the first coating film 121 away from the first solder tape 111 can be relatively flat, which is beneficial to increasing the contact area between the first busbar 131 and the first coating film 121, avoiding a large number of stress concentration points between the uneven surface of the first coating film 121 and the first busbar 131, and further avoiding the problem of fragmentation of the back-contact battery 100 caused by stress concentration.

[0056] Similarly, in a direction perpendicular to the surface of the back-contact battery 100, the thickness of the second coating film 122 can be greater than the height of the first solder tape 111 and / or the height of the second solder tape 112. In this way, the second coating film 122 can wrap the first solder tape 111 and / or the second solder tape 112, and the surface of the second coating film 122 away from the back-contact battery 100 can be relatively flat.

[0057] In some embodiments, the thickness of the second coating film 122 can be greater than the thickness of the first coating film 121. In this way, the distance between the surface of the second coating film 122 away from the back-contact battery 100 and the surface of the back-contact battery 100 can be close to the distance between the surface of the first busbar 131 away from the back-contact battery 100 and the surface of the back-contact battery 100. In other words, relative to the surface of the back-contact battery 100, the difference in height between the surface of the second coating film 122 away from the back-contact battery 100 and the surface of the first busbar 131 away from the back-contact battery 100 is relatively reduced, thereby avoiding the problem of uneven filling of the adhesive film caused by the height difference during the subsequent lamination process.

[0058] In some embodiments, the melting point of the first coating film 121 is higher than that of the second coating film 122. The first coating film 121 can be used to isolate the first bus bar 131 from the intermediate battery 102. Since the melting point of the first coating film 121 is relatively high, it can avoid the problem of electric leakage caused by the contact between the first bus bar 131 and the solder tapes with different polarities on the intermediate battery 102 due to excessive melting of the first coating film 121 during the subsequent lamination process.

[0059] In Figure 1 , the same first coating film 121 covers the surfaces of multiple intermediate batteries 102. In this way, in the process step of laying the first coating film 121, after laying the first solder tapes 111 on multiple intermediate batteries 102, a whole piece of the first coating film 121 can be used to cover multiple intermediate batteries 102. On the one hand, it can help improve the laying efficiency of the first coating film 121. On the other hand, it can assist in fixing the relative positions between multiple intermediate batteries 102 through the first coating film 121, and avoid the problem that the first solder tapes 111 pull the intermediate batteries 102 during subsequent process steps, resulting in defects in the intermediate batteries 102.

[0060] In other embodiments, each intermediate battery can also be covered with a first coating film respectively.

[0061] In Figure 1 , taking the width of the first coating film 121 in the second direction Y being the same as the width of the back-contact battery 100 as an example, it does not constitute a limitation on the size of the second coating film 122. In other embodiments, the width of the first coating film in the second direction is greater than the width of the back-contact battery, so that the alignment accuracy of the first coating film can be reduced and the laying efficiency of the first coating film can be improved. When each intermediate battery is covered with a first coating film respectively, the size of the first coating film can be greater than the size of the back-contact battery (the size includes the width in the first direction and / or the width in the second direction).

[0062] Similarly, in Figure 1 , taking the size of the second coating film 122 being the same as the size of the back-contact battery 100 as an example (the size includes the width in the first direction X and the width in the second direction Y), it does not constitute a limitation on the size of the second coating film 122. In other embodiments, the size of the second coating film can also be greater than the size of the back-contact battery to improve the laying efficiency of the second coating film.

[0063] Figure 4 FIG. [ID] is a schematic structural diagram of another photovoltaic module provided by an embodiment of the present application.

[0064] Reference Figure 4, in some embodiments, at least two cell strings 10 are arranged along the first direction X, and the end cells 101 of the two cell strings 10 without the second solder strip 112 are arranged adjacent to each other. The photovoltaic module may further include: a third solder strip 113 and a second bus bar 132. One end of the third solder strip 113 is located on the surface of the end cell 101 of one cell string 10, and the other end is located on the surface of the end cell 101 of the other cell string 10; the second bus bar 132 is located on the intermediate cell 102 adjacent to the end cell 101, and the second bus bar 132 is located on the side of the first encapsulant film 121 away from the back contact cell 100. The ends of multiple third solder strips 113 are welded to the same second bus bar 132; the second encapsulant film 122 is also located on the side of the third solder strip 113 away from the end cell 101 and covers the surface of the end cell 101. That is, two adjacent cell strings 10 along the first direction X are connected in parallel through a third bus bar 133, and two adjacent cell strings 10 along the second direction Y are connected in series after being welded by a first bus bar 131.

[0065] After connecting two cell strings 10 in parallel through the third solder strip 113, the current on the third solder strip 113 is led out through the second bus bar 132. The second bus bar 132 is located on the side of the first encapsulant film 121 away from the back contact cell 100. In this way, the first encapsulant film 121 can be used to isolate the intermediate cell 102 from the second bus bar 132 to avoid the problem of leakage between the second bus bar 132 and the solder strips with different polarities on the intermediate cell 102; at the same time, the second bus bar 132 is located on the intermediate cell 102, which is beneficial to hiding the second bus bar 132 to the back of the back contact cell 100, avoiding the second bus bar 132 occupying the effective area of the photovoltaic module, and thus being beneficial to improving the light conversion efficiency of the photovoltaic module.

[0066] In some embodiments, the second bus bar includes a second body portion and a second welding portion. The second welding portion is used to weld the second bus bar corresponding to one cell string to the second bus bar corresponding to another cell string. The second welding portions of the second bus bars corresponding to the two cell strings can be directly welded, or welded to the same connecting piece to achieve electrical connection. In the direction perpendicular to the surface of the back contact cell, the thickness of the second welding portion is less than the thickness of the second body portion. In this way, it is beneficial that the total thickness of the position corresponding to the second welding portion after welding is less than or equal to the thickness of the second body portion, avoiding the problem of stress concentration caused by excessive thickness at the position corresponding to the second welding portion after welding and resulting in fragmentation of the back contact cell.

[0067] In some embodiments, the photovoltaic module may further include: an isolation film (not shown in the figure), and the isolation film is located between the first bus bar and the first encapsulant film. The isolation film can further improve the isolation effect between the first bus bar and the intermediate cell and avoid the problem of leakage between the first bus bar and the intermediate cell.

[0068] In some embodiments, the isolation film may also be located between the second bus bar and the first coating film to further improve the isolation effect between the second bus bar and the intermediate battery and avoid the occurrence of leakage problems between the second bus bar and the intermediate battery.

[0069] When the isolation film is located between the first bus bar and the first coating film, the surface of the isolation film facing the first coating film has an adhesive layer, and / or the surface of the isolation film facing the first bus bar has an adhesive layer. When the isolation film is located between the second bus bar and the second coating film, the surface of the isolation film facing the first coating film has an adhesive layer, and / or the surface of the isolation film facing the second bus bar has an adhesive layer. The surface of the isolation film facing the first coating film having an adhesive layer can facilitate fixing the relative position between the isolation film and the first coating film, and the surface of the isolation film facing the first bus bar or the second bus bar having an adhesive layer can facilitate fixing the relative position between the isolation film and the first bus bar or the second bus bar. In this way, the laying stability of the isolation film can be improved.

[0070] In some embodiments, the melting point of the isolation film is higher than that of the first coating film. In this way, it can be beneficial to increase the isolation effect between the first bus bar and / or the second bus bar and the intermediate battery, and avoid the problem of leakage caused by the first bus bar and / or the second bus bar contacting the solder tapes of different polarities on the intermediate battery due to a large degree of melting of the first coating film during the lamination process.

[0071] It should be noted that in Figure 1 and Figure 4 taking the number of back-contact batteries 100 in a battery string 10 as 4 as an example, it does not limit the number of back-contact batteries 100 in the battery string 10. In other embodiments, the number of back-contact batteries in a battery string may be 3, 5, 7, 10, etc.

[0072] In the photovoltaic module provided by the embodiment of the present application, adjacent back-contact cells 100 are connected by a first solder tape 111 to form a battery string 10. The end cell 101 at the first or the last position leads out current to the first bus bar 131 through a second solder tape 112. The first coating film 121 is used to fix the position of the first solder tape 111 on the intermediate cell 102, and the second coating film 122 is used to fix the positions of the first solder tape 111 and the second solder tape 112 on the end cell 101. In this way, the problem that the back-contact cell 100 is warped due to high-temperature welding can be avoided, which is beneficial to improving the yield of the photovoltaic module. The first bus bar 131 is located on the intermediate cell 102 adjacent to the end cell 101, and the first bus bar 131 is located on the side of the first coating film 121 away from the back-contact cell 100. In this way, the first coating film 121 can be used to isolate the intermediate cell 102 from the first bus bar 131 to avoid the problem of leakage between the first bus bar 131 and the solder tapes with different polarities on the intermediate cell 102. At the same time, since the first bus bar 131 is located on the intermediate cell 102, it is beneficial to hide the first bus bar 131 behind the back-contact cell 100, avoiding the first bus bar 131 occupying the effective area of the photovoltaic module, which is beneficial to improving the light conversion efficiency of the photovoltaic module. The ends of the first bus bars 131 corresponding to the two battery strings 10 arranged along the second direction Y are electrically connected by welding. In this way, in the preparation step of the battery string 10, the first bus bar 131 can already be welded to the second solder tape 112. During the series connection process of the battery strings 10, welding the first bus bars 131 of different battery strings 10 can achieve the series connection of multiple battery strings 10, thereby improving the manufacturing efficiency of the photovoltaic module.

[0073] Correspondingly, another embodiment of the present application further provides a manufacturing method of a photovoltaic module, which can be used to manufacture the photovoltaic module provided in the above embodiment. For the same or corresponding parts as the previous embodiment, reference can be made to the corresponding description of the previous embodiment, and details will not be repeated below.

[0074] Figures 5 to 9 It is a schematic structural diagram corresponding to each step of a manufacturing method of a photovoltaic module provided by an embodiment of the present application.

[0075] Reference Figures 5 to 9 In another aspect, an embodiment of the present application further provides a manufacturing method of a photovoltaic module, including:

[0076] S11. Prepare the battery string 10. The steps of preparing the battery string 10 include:

[0077] S21. Reference Figure 5, a back-contact battery 100 is provided, and a plurality of back-contact batteries 100 are arranged in sequence along the first direction X. The back-contact batteries 100 arranged at the first and the last are end batteries 101, and the back-contact batteries 100 located between the end batteries 101 are intermediate batteries 102.

[0078] S22. Refer to Figure 6 , a first welding strip 111 is laid, and both ends of the first welding strip 111 are respectively located on the surfaces of two adjacent back-contact batteries 100 along the first direction X.

[0079] S23. Refer to Figure 7 , a first film 121 is laid. The first film 121 is located on the side of the first welding strip 111 away from the intermediate battery 102 and covers the surface of the intermediate battery 102.

[0080] In Figure 7 , taking the example that a plurality of intermediate batteries 102 are covered by the whole first film 121, on the one hand, it is beneficial to improve the laying efficiency of the first film 121. On the other hand, the relative positions between the plurality of intermediate batteries 102 can be assisted and fixed by the first film 121, avoiding the problem that the first welding strip 111 causes pulling on the intermediate battery 102 and resulting in defects of the intermediate battery 102 in subsequent process steps. In other embodiments, each intermediate battery can be respectively covered with a first film.

[0081] S24. Refer to Figure 8 , a second welding strip 112 and a first bus bar 131 are laid. The second welding strip 112 is located on the surface of at least one end battery 101. The first bus bar 131 is located on the intermediate battery 102 adjacent to the end battery 101, and the first bus bar 131 is located on the side of the first film 121 away from the back-contact battery 100. The ends of the plurality of second welding strips 112 close to the intermediate battery 102 are welded to the same first bus bar 131.

[0082] In some embodiments, before laying the second welding strip 112 and the first bus bar 131, it includes: laying an isolation film (not shown in the figure) on the first film 121 corresponding to the intermediate battery 102 adjacent to the end battery 101, and the isolation film is located on the side of the first film 121 adjacent to the end battery 101; laying the second welding strip 112 and the first bus bar 131 includes: laying the first bus bar 131 on the isolation film. The isolation film can further improve the isolation effect between the first bus bar and the intermediate battery, avoiding the problem of electric leakage between the first bus bar and the intermediate battery.

[0083] Before laying the second welding strip 112 and the first bus bar 131, the second welding strip 112 and the first bus bar 131 can have been welded into an assembly, which is beneficial to improving the manufacturing efficiency of the photovoltaic module.

[0084] S25. Refer toFigure 9 , lay the second film 122. The second film 122 is located on the side of the first welding strip 111 and the second welding strip 112 away from the end cell 101, and covers the surface of the end cell 101.

[0085] S12. Refer to Figure 1 , connect multiple battery strings 10. At least two battery strings 10 are arranged along the second direction Y, and the ends of the first busbars 131 of the two battery strings 10 are connected by welding.

[0086] Return to reference Figure 2 , in some embodiments, the first busbars 131 corresponding to the two battery strings 10 can be directly welded. Or, return to reference Figure 3 , in other embodiments, the first busbars 131 corresponding to the two battery strings 10 are both welded to the same connecting piece 1313, thereby realizing electrical connection.

[0087] Return to reference Figure 4 , in some embodiments, in step S24, while laying the first busbar 131 and the second welding strip 112, the second busbar 132 and the third welding strip 113 are also laid. Specifically, arrange the two battery strings 10 along the second direction Y, lay the second welding strip 112 on the end cells 101 at both ends along the second direction Y, lay the third welding strip 113 on the adjacent end cells 101 in the two battery strings 10. One end of the third welding strip 113 is located on the surface of the end cell 101 of one battery string 10, and the other end is located on the surface of the end cell 101 of the other battery string 10. The second busbar 132 is located on the intermediate cell 102 adjacent to the end cell 101, and the second busbar 132 is located on the side of the first film 121 away from the back-contact cell 100. The ends of multiple third welding strips 113 are welded to the same second busbar 132. Further, in step 25, during the process of laying the second film 122, the second film 122 is also located on the side of the third welding strip 113 away from the end cell 101, and covers the surface of the end cell 101. In step 12, when connecting multiple battery strings 10, two adjacent battery strings 10 along the first direction X are connected in parallel through the third busbar 133, and two adjacent battery strings 10 along the second direction Y are connected in series after being welded through the first busbar 131.

[0088] After step 12 of connecting multiple battery strings, it may further include: laying the first cover plate and the first encapsulation layer; laying the connected battery strings on the first encapsulation layer; laying the second encapsulation layer and the second cover plate on the connected battery strings; performing a lamination process to obtain a photovoltaic module.

[0089] The materials of the first encapsulation layer and the second encapsulation layer can both adopt organic encapsulation films such as ethylene-vinyl acetate copolymer (EVA) film, polyolefin elastomer (POE) film or polyvinyl butyral (PVB) film.

[0090] Both the first cover plate and the second cover plate can be cover plates with light-transmitting functions such as glass cover plates and plastic cover plates.

[0091] In the manufacturing method of the photovoltaic module provided by the embodiment of the present application, after arranging the back-contact cells 100, the first welding tape 111 and the first film 121 are first laid. The first welding tape 111 is used to connect a plurality of back-contact cells 100 in series. Among them, the back-contact cells 100 at the first and the last are end cells 101, and the back-contact cells 100 between the end cells 101 are intermediate cells 102. The first film 121 is used to fix the position of the first welding tape 111 on the intermediate cells 102, and is also used to isolate the intermediate cells 102 from the first bus bar 131 in subsequent process steps, so as to avoid the problem of electric leakage between the first bus bar 131 and the welding tapes with different polarities on the intermediate cells 102; then the second welding tape 112, the second bus bar 132 and the second film 122 are laid on the end cells 101. The end cells 101 lead the current to the first bus bar 131 through the second welding tape 112. The first bus bar 131 is located on the intermediate cells 102. In this way, it is beneficial to hide the first bus bar 131 on the back of the back-contact cells 100, avoid the first bus bar 131 occupying the effective area of the photovoltaic module, and thus is beneficial to improving the light conversion efficiency of the photovoltaic module. The second film 122 is used to fix the positions of the first welding tape 111 and the second welding tape 112 on the end cells 101. During the process of connecting the battery strings 10, the first bus bars 131 of different battery strings 10 are welded to realize the connection of multiple battery strings 10, thus improving the manufacturing efficiency of the photovoltaic module.

[0092] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present application. In actual applications, various changes can be made in form and details without departing from the spirit and scope of the present application. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. A photovoltaic module, characterized in that, Comprising: A plurality of battery strings, each battery string comprising: back-contact batteries, first solder tapes, first laminating films, second solder tapes, second laminating films, and first busbars; A plurality of the back-contact batteries are arranged in sequence along a first direction. The back-contact batteries at the first and last positions in the battery string are end batteries, and the back-contact batteries between the end batteries are intermediate batteries; Two ends of the first solder tape are respectively located on the surfaces of two adjacent back-contact batteries along the first direction; The first laminating film is located on a side of the first solder tape away from the intermediate battery and covers the surface of the intermediate battery; The second solder tape is located on the surface of at least one of the end batteries; The second laminating film is located on a side of the first solder tape and the second solder tape away from the end battery and covers the surface of the end battery; The first busbar is located on the intermediate battery adjacent to the end battery, and the first busbar is located on a side of the first laminating film away from the back-contact battery. The ends of a plurality of the second solder tapes close to the intermediate battery are welded to the same first busbar; At least two of the battery strings are arranged along a second direction, and the ends of the first busbars of two of the battery strings are electrically connected by welding.

2. The photovoltaic module according to claim 1, wherein The first busbar includes a first body portion and a first welding portion. In a direction perpendicular to the surface of the back-contact battery, the thickness of the first welding portion is less than the thickness of the first body portion. The first welding portion is used for welding and connecting the first busbar corresponding to one battery string and the first busbar corresponding to another battery string.

3. The photovoltaic module according to claim 2, wherein The first welding portions of the first busbars corresponding to two of the battery strings are welded to the same connecting piece.

4. The photovoltaic module according to claim 2, characterized in that, The first welding portions of the first busbars corresponding to two of the battery strings are directly welded.

5. The photovoltaic module according to claim 1, wherein At least two of the battery strings are arranged along the first direction, and the end batteries without the second solder tape in two of the battery strings are arranged adjacent to each other; The photovoltaic module further comprises: a third solder tape and a second busbar. One end of the third solder tape is located on the surface of the end battery of one battery string, and the other end is located on the surface of the end battery of another battery string. The second busbar is located on the intermediate battery adjacent to the end battery, and the second busbar is located on a side of the first laminating film away from the back-contact battery. The ends of a plurality of the third solder tapes are welded to the same second busbar. The second laminating film is further located on a side of the third solder tape away from the end battery and covers the surface of the end battery.

6. The photovoltaic module according to claim 1, wherein Further comprising: An isolation film, the isolation film being located between the first busbar and the first laminating film.

7. The photovoltaic module according to claim 6, characterized in that, The surface of the isolation film facing the first laminating film has an adhesive layer, and / or the surface of the isolation film facing the first busbar has an adhesive layer.

8. The photovoltaic module according to claim 1, wherein, The same first laminating film covers the surfaces of a plurality of the intermediate batteries.

9. A manufacturing method of a photovoltaic module, characterized in that, Comprising: Preparing a battery string, the steps of preparing the battery string comprising: Provided are back-contact batteries, and a plurality of the back-contact batteries are arranged in sequence along a first direction. The back-contact batteries arranged at the first and the last positions are end batteries, and the back-contact batteries located between the end batteries are intermediate batteries; Lay a first solder tape, and both ends of the first solder tape are respectively located on the surfaces of two adjacent back-contact batteries along the first direction; Lay a first film covering. The first film covering is located on a side of the first solder tape away from the intermediate batteries and covers the surfaces of the intermediate batteries; Lay a second solder tape and a first bus bar. The second solder tape is located on the surface of at least one of the end batteries. The first bus bar is located on the intermediate battery adjacent to the end battery, and the first bus bar is located on a side of the first film covering away from the back-contact batteries. The ends of the plurality of second solder tapes close to the intermediate batteries are welded to the same first bus bar; Lay a second film covering. The second film covering is located on a side of the first solder tape and the second solder tape away from the end batteries and covers the surfaces of the end batteries; Connect a plurality of the battery strings. At least two battery strings are arranged along a second direction, and the ends of the first bus bars of the two battery strings are connected by welding.

10. The manufacturing method of the photovoltaic module according to claim 9, wherein, Before laying the second solder tape and the first bus bar, it includes: laying an isolation film on the first film covering corresponding to the intermediate battery adjacent to the end battery. The isolation film is located on a side of the first film covering adjacent to the end battery; laying the second solder tape and the first bus bar includes: laying the first bus bar on the isolation film.

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