Photovoltaic module

Abstract

The invention relates to the field of photovoltaic modules, and provides a photovoltaic module which is at least beneficial to solving the problem of connection failure between a welding strip and a battery piece. The photovoltaic module comprises a plurality of battery pieces arranged along a first direction; the welding strip extends along the first direction and is used for connecting two adjacent battery pieces; the first covering film is located at the two ends of the battery piece in the first direction and covers the surface of the battery piece, the first covering film extends in the second direction, the second direction intersects with the first direction, and the welding strips in the second direction are located at the portions, located at the two ends of the battery piece in the first direction, of the battery piece and located between the first covering film and the battery piece; the second covering film covers the surface of the battery piece and is located between the two first covering films, the second covering film and the first covering films are arranged in a spaced mode, the crosslinking degree of the second covering film is smaller than that of the first covering films, and the parts, located in the middle of the battery piece in the first direction, of the multiple welding strips in the second direction are located between the second covering film and the battery piece.

Description

Technical Field

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

[0002] Solar cells are devices that directly convert light energy into electricity through the photoelectric or photochemical effect. During the photovoltaic module manufacturing process, multiple cells are connected using solder ribbons to form a string. Lamination, framing, and other processes are then performed to form the photovoltaic module. The reliability of the connection between the solder ribbons and the corresponding cells can affect the reliability of the photovoltaic module.

[0003] Conventional soldering requires high-temperature welding to alloy the ribbon with the grid lines. Due to the different thermal expansion coefficients of the ribbon and the cell, thermal conductivity also differs, which can cause the cell to warp after welding. Warping can lead to defects such as hidden cracks and cell breakage, resulting in reduced reliability and yield during cell lamination and battery assembly production.

[0004] In order to avoid the use of high-temperature welding methods, low-melting-point metals can be used as solder to make solder strips, which are first fixed to the surface of the solar cell by glue or coating; then in the lamination process of the photovoltaic module, the temperature and pressure of the laminator are used to help the low-melting-point solder strips and the grid lines be combined together.

[0005] However, the use of a dispensing process or a laminating process for low-temperature solder strips can easily lead to connection failure between the solder strips and the battery cells. Summary of the Invention

[0006] The embodiments of the present application provide a photovoltaic module that at least helps to solve the problem of connection failure between the welding ribbon and the solar cell.

[0007] According to some embodiments of the present application, on the one hand, the embodiments of the present application provide a photovoltaic component, comprising: a plurality of battery cells arranged along a first direction; a welding strip extending along the first direction for connecting two adjacent battery cells; a first coating, the first coating is located at both ends of the battery cell along the first direction and covers the surface of the battery cell, the first coating extends along a second direction, the second direction intersects with the first direction, and the plurality of welding strips along the second direction are located at the parts of the battery cell at both ends along the first direction, and are located between the first coating and the battery cell; a second coating, the second coating covers the surface of the battery cell and is located between the two first coatings, the second coating is spaced apart from the first coating, and the cross-linking degree of the second coating is less than that of the first coating, and the plurality of welding strips along the second direction are located at the part of the battery cell in the middle position along the first direction, and are located between the second coating and the battery cell.

[0008] In some embodiments, the first cover film has a grammage greater than the grammage of the second cover film.

[0009] In some embodiments, the first coating has a grammage range of 130 g / m 2 ~180g / m 2 ; The second coating weight range is 80g / m 2 ~130g / m 2 .

[0010] In some embodiments, along the first direction, the width of the first covering film is a first width, the length of the first covering film covering the end of the welding strip is a first length, and the ratio of the first length to the first width is 0.5 to 0.75.

[0011] In some embodiments, the first width is 13 mm to 20 mm; and the first length is 10 mm to 15 mm.

[0012] In some embodiments, along the first direction, the width of the gap between the first covering film and the second covering film is 0.5 mm to 3 mm.

[0013] In some embodiments, the melt index of the first coating film is less than the melt index of the second coating film.

[0014] In some embodiments, the melt index of the first coating is 8 g / 10 min to 20 g / 10 min; the melt index of the second coating is 3 g / 10 min to 10 g / 10 min.

[0015] In some embodiments, the length of the first cover film and / or the second cover film along the second direction is greater than the length of the battery cell.

[0016] In some embodiments, the edge of the first cover film is away from the edge of the second cover film and extends beyond the edge of the battery cell.

[0017] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0018] In a photovoltaic module provided by an embodiment of the present application, adjacent cells are connected by a soldering ribbon. A first covering film is provided at each end of the cell along a first direction, the first covering film being used to secure the soldering ribbon at the cell's ends along the first direction. A second covering film is provided between the two first covering films, the second covering film being used to secure the soldering ribbon at the cell's center. The second covering film has a lower degree of crosslinking than the first covering film, thereby providing a stronger bonding strength to the first covering film than to the second covering film. This higher bonding strength of the first covering film can prevent cold solder joints between the soldering ribbon and the cell's ends during lamination. Furthermore, the higher bonding strength of the first covering film can improve the stability of the connection between the soldering ribbon and the cell's ends over the long-term use of the photovoltaic module, preventing connection failure between the soldering ribbon and the cell, thereby preventing power degradation of the photovoltaic module. Furthermore, when the first and second covering films are integral, the cooling and shrinkage of the second covering film can pull on the first covering film, thereby reducing the pressure of the first covering film on the soldering ribbon, which can easily reduce the bonding strength between the soldering ribbon and the cell. The embodiment of the present application also provides a gap between the first film and the second film. In this way, during the lamination process, the melting and cooling and solidification processes of the first film and the second film can be prevented from interfering with each other, thereby improving the stability of the first film fixing the welding strip. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures 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.

[0020] Figure 1 A top view of a photovoltaic module provided in an embodiment of the present application;

[0021] Figure 2 for Figure 1 Schematic diagram of the cross-section structure along the AA1 direction;

[0022] Figure 3 A top view of another photovoltaic module provided in an embodiment of the present application;

[0023] Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure along the BB1 direction.

[0024] Description of reference numerals:

[0025] 100 , battery cell; 110 , solder ribbon; 121 , first covering film; 122 , second covering film. DETAILED DESCRIPTION

[0026] As known from the background art, the use of a dispensing process or a laminating process for a low-temperature solder ribbon can easily lead to connection failure between the solder ribbon and the battery cell.

[0027] After production, photovoltaic modules usually need to undergo a TC (Temperature Cycling Test). The TC test simulates the temperature fluctuations experienced by photovoltaic modules in actual use by cycling between set high and low temperatures to accelerate mechanical failure caused by coefficient of thermal expansion (CTE) mismatch. In the test, photovoltaic modules are subjected to extreme temperature changes.

[0028] During the TC test, it was found that due to the cyclic changes between high and low temperatures, the thermal expansion coefficients of the cell and the solder ribbon did not match, resulting in a greater risk of connection failure at the starting and ending points of the connection between the solder ribbon and the cell. This prevented the current at both ends of the cell from being transferred to the solder ribbon, causing a high degree of power attenuation in the photovoltaic module.

[0029] In the photovoltaic module provided by the embodiment of the present application, the first coating is used to fix the welding tape at the positions of the two end portions of the battery cell along the first direction; and the second coating is used to fix the welding tape at the position of the middle portion of the battery cell. The cross-linking degree of the second coating is lower than that of the first coating, so that the bonding strength of the first coating is stronger than that of the second coating. On the one hand, it can avoid the problem of cold welding between the welding tape and the two ends of the battery cell during the lamination process, and on the other hand, it can improve the connection stability of the welding tape and the two ends of the battery cell during the long-term use of the photovoltaic module. The embodiment of the present application also provides a gap between the first coating and the second coating. In this way, during the lamination process, it can avoid the mutual interference of the melting and cooling solidification processes of the first coating and the second coating, thereby improving the stability of the first coating in fixing the welding tape to the two ends of the battery cell.

[0030] 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 number, specific order or primary and secondary relationship of the indicated technical features.

[0031] In the description of the embodiments of the present application, “multiple” means more than two, unless otherwise clearly and specifically defined.

[0032] References to "embodiments" herein 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.

[0033] 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.

[0034] In the description of the embodiments of the present application, technical terms such as "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 orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They 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. Therefore, they cannot be understood as limiting the embodiments of the present application.

[0035] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," 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; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0036] 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 on another component or on the surface of another component, the component can be "directly" located on the surface of the other component, or there can be a third component between the two components. On the contrary, when describing a component on the surface of another component or when another component is 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 partial edge of the entire surface.

[0037] In the description of the embodiments of the present application, when a component “includes” another component, unless otherwise stated, other components are not excluded, and other components may be further included.

[0038] The terms used in the description of the various embodiments described herein are for describing specific embodiments only and are not intended to be limiting. As used in the description of the various embodiments described and the appended claims, "components" are also intended to include plural forms unless the context clearly indicates otherwise.

[0039] 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.

[0040] Figure 1 A top view of a photovoltaic module provided in an embodiment of the present application; Figure 2 for Figure 1 Schematic diagram of the cross-section structure along the AA1 direction; Figure 3 A top view of another photovoltaic module provided in an embodiment of the present application; Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure along the BB1 direction.

[0041] refer to Figures 1 to 4 The photovoltaic module provided in the embodiment of the present application includes: a cell 100, a welding ribbon 110, a first covering film 121 and a second covering film 122.

[0042] The plurality of battery cells 100 are arranged along a first direction X.

[0043] The welding ribbon 110 extends along the first direction X and is used to connect two adjacent battery cells 100 .

[0044] The first covering film 121 is located at both ends of the battery cell 100 along the first direction X and covers the surface of the battery cell 100. The first covering film 121 extends along the second direction Y, which intersects the first direction X. The plurality of welding ribbons 110 along the second direction Y are located at both ends of the battery cell 100 along the first direction X, and are located between the first covering film 121 and the battery cell 100.

[0045] The second covering film 122 covers the surface of the battery cell 100 and is located between the two first covering films 121. The second covering film 122 is spaced apart from the first covering films 121, and the crosslinking degree of the second covering film 122 is lower than that of the first covering film 121. The portion of the plurality of welding ribbons 110 located in the middle of the battery cell 100 in the first direction X along the second direction Y is located between the second covering film 122 and the battery cell 100.

[0046] In the photovoltaic module provided in the embodiment of the present application, adjacent battery cells 100 are connected by welding strips 110, and a first covering film 121 is provided at both ends of the battery cell 100 along the first direction X. The first covering film 121 is used to fix the position of the welding strip 110 at the two end parts of the battery cell 100 along the first direction X; the second covering film 122 is located between the two first covering films 121, and the second covering film 122 is used to fix the position of the welding strip 110 in the middle part of the battery cell 100. The crosslinking degree of the second covering film 122 is lower than that of the first covering film 121. This allows the first covering film 121 to have a stronger bonding strength than the second covering film 122. On the one hand, during the lamination process, the greater bonding strength of the first covering film 121 can prevent the occurrence of cold solder joints between the solder ribbon 110 and the ends of the cell 100. On the other hand, during the long-term use of the photovoltaic module, the greater bonding strength of the first covering film 121 helps improve the stability of the connection between the solder ribbon 110 and the ends of the cell 100, preventing connection failure between the solder ribbon 110 and the ends of the cell 100, thereby preventing power degradation of the photovoltaic module. Furthermore, when the first covering film 121 and the second covering film 122 are integral, the cooling and shrinkage of the second covering film 122 will pull on the first covering film 121, thereby reducing the pressure of the first covering film 121 on the solder ribbon 110, which can easily lead to a decrease in the connection strength between the solder ribbon 110 and the cell 100. The embodiment of the present application also provides a gap between the first coating 121 and the second coating 122. In this way, during the lamination process, the melting and cooling and solidification processes of the first coating 121 and the second coating 122 can be prevented from interfering with each other, thereby improving the stability of the first coating 121 fixing the welding strip 110.

[0047] refer to Figure 1 and Figure 2In some embodiments, the cell 100 may be a BC cell (Back Contact), such as an IBC cell (Interdigitated Back Contact), an HPBC cell (Hybrid Passivated Back Contact), a TBC cell that combines TOPCon (Tunnel Oxide Passivated Contact) technology with IBC technology, or an HBC cell that combines HIT / HJT (Heterojunction Technology) technology with IBC technology. Of course, other types of back contact cells are also possible. Thus, grid lines of different polarities (not shown) on the cell 100 are all located on the same side surface of the cell 100.

[0048] refer to Figure 3 and Figure 4 In other embodiments, the cell 100 can be any one of a PERC cell (Passivated Emitter and Rear Cell), a PERT cell (Passivated Emitter and Rear Totally-diffused cell), a TOPCon cell (Tunnel Oxide Passivated Contact), or a HIT / HJT cell (Heterojunction Technology). Thus, grid lines of different polarities (not shown) on the cell 100 are located on both sides of the cell 100.

[0049] One end of the soldering ribbon 110 is connected to one of the positive grid lines or the negative grid lines on a cell 100, and the other end is connected to the other of the positive grid lines or the negative grid lines on another cell 100, so that adjacent cells 100 are connected in series through the soldering ribbon 110. Figure 1 and Figure 2 When the battery cell 100 is a back contact battery, both ends of the welding ribbon 110 are located on the same side surface of the battery cell 100; Figure 3 and Figure 4 When the battery cell 100 is not a back contact battery, one end of the welding ribbon 110 is located on the front side of one battery cell 100 , and the other end of the welding ribbon 110 is located on the back side of another battery cell 100 .

[0050] The cell 100 may also be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell or a multi-compound solar cell. The multi-compound solar cell may specifically be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell or a perovskite solar cell.

[0051] In some embodiments, the gram weight of the first covering film 121 is greater than the gram weight of the second covering film 122. Thus, when the first covering film 121 and the second covering film 122 of the same area are prepared, the thickness of the first covering film 121 is thicker than that of the second covering film 122. Figure 2 or Figure 4 When the thickness of the first covering film 121 is thicker, the first covering film 121 will provide greater compressive stress to the portions of the soldering ribbon 110 located at both ends of the battery cell 100 along the first direction X during the lamination process, thereby helping to improve the connection stability between the soldering ribbon 110 and the two ends of the battery cell 100, thereby avoiding the problem of connection failure between the soldering ribbon 110 and the end of the battery cell 100 during subsequent testing or use.

[0052] The first coating 121 has a grammage range of 130 g / m 2 ~180g / m 2 , for example, it can be 130g / m 2 , 133g / m 2 , 138g / m 2 , 140g / m 2 , 144g / m 2 , 146g / m 2 , 150g / m 2 , 152g / m 2 , 157g / m 2 , 160g / m 2 , 163g / m 2 , 167g / m 2 , 170g / m 2 , 175g / m 2 or 180g / m 2 .

[0053] The second coating 122 has a grammage range of 80 g / m 2 ~130g / m 2 , for example, it can be 80g / m 2 , 82g / m 2 , 86g / m 2 , 90g / m 2 , 93g / m 2 , 97g / m 2 , 100g / m 2 , 105g / m 2, 110g / m 2 , 113g / m 2 , 116g / m 2 , 120g / m 2 , 124g / m 2 , 126g / m 2 or 130g / m 2 .

[0054] In some embodiments, the cell 100 has multiple solder joints (not shown in the figures), and each solder ribbon 110 is connected to multiple solder joints arranged along the first direction X. The orthographic projection of the first covering film 121 on the cell 100 covers at least the first and last solder joints arranged on the cell 100 along the first direction X. The solder joints are used for soldering to the solder ribbon 110, and the first covering film 121 covers the first and last solder joints, which can help ensure that the starting and ending ends of the solder ribbon connected to the cell 100 are fully fixed, thereby avoiding the problem of connection failure between the solder ribbon 110 and the end of the cell 100 during subsequent testing or use.

[0055] In some embodiments, before covering with the first cover film 121 and the second cover film 122, the soldering ribbon 110 may be pre-welded to the soldering points to pre-fix the position of the soldering ribbon 110 on the battery cell 100, and then the first cover film 121 and the second cover film 122 further secure the soldering ribbon 110. In other embodiments, before covering with the first cover film 121 and the second cover film 122, the soldering ribbon 110 may not be pre-welded to the soldering points, and the soldering ribbon 110 may be directly fixed to the battery cell 100 through the first cover film 121 and the second cover film 122, and then the soldering ribbon 110 may be welded to the soldering points using a subsequent lamination process.

[0056] refer to Figure 1 or Figure 3In the first direction X, the width of the first coating 121 is a first width W1, the length of the first coating 121 covering the end of the welding strip 110 is a first length L1, and the ratio of the first length L1 to the first width W1 is 0.5 to 0.75, for example, it can be 0.5, 0.55, 0.6, 0.63, 0.67, 0.7, 0.73 or 0.75. Since the thermal expansion coefficient of the soldering ribbon 110 is different from that of the battery cell 100, the connection between the end of the soldering ribbon 110 and the battery cell 100 is more likely to shrink than the connection between the middle part of the soldering ribbon 110 and the battery cell 100, resulting in connection failure between the soldering ribbon 110 and the battery cell 100. Therefore, the ratio of the first length L1 to the first width W1 is between 0.5 and 0.75, which is conducive to the first covering film 121 providing sufficient fixing pressure on the end of the soldering ribbon 110, thereby avoiding connection failure between the soldering ribbon 110 and the end of the battery cell 100 during subsequent testing or use.

[0057] The first width W1 may be 13 mm to 20 mm, for example, 13 mm, 13.6 mm, 14 mm, 14.4 mm, 15 mm, 15.5 mm, 16 mm, 16.4 mm, 17 mm, 17.3 mm, 18 mm, 18.5 mm, 19 mm, 19.6 mm or 20 mm.

[0058] The first length L1 may be 10 mm to 15 mm, for example, 10 mm, 10.5 mm, 11 mm, 11.3 mm, 12 mm, 12.4 mm, 13 mm, 13.6 mm, 14 mm, 14.5 mm or 15 mm.

[0059] refer to Figure 1 or Figure 3 Along the first direction X, the gap width C between the first coating 121 and the second coating 122 is 0.5 mm to 3 mm, for example, 0.5 mm, 0.8 mm, 1 mm, 1.3 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.7 mm, or 3 mm. The gap between the first coating 121 and the second coating 122 needs to be large enough to prevent interference between the first coating 121 and the second coating 122 during the melting and cooling solidification processes. However, the gap between the first coating 121 and the second coating 122 should not be too large to prevent bubbles from forming during the subsequent lamination process.

[0060] In some embodiments, the melt index of the first covering film 121 is lower than the melt index of the second covering film 122. Thus, during the lamination process, at the same temperature, the fluidity of the first covering film 121 after melting is lower than the fluidity of the second covering film 122 after melting, so that the first covering film 121 can still provide sufficient compressive stress to the soldering ribbon 110 after melting, promote alloying between the soldering ribbon 110 and the grid lines on the battery cell 100, and increase the welding tension between the portion of the soldering ribbon 110 located at the end of the battery cell 100 and the battery cell 100, thereby avoiding the problem of connection failure between the soldering ribbon 110 and the end of the battery cell 100 during subsequent testing or use.

[0061] The melt index of the first coating 121 is 8 g / 10 min to 20 g / 10 min, for example, it can be 8 g / 10 min, 9 g / 10 min, 10 g / 10 min, 11 g / 10 min, 12 g / 10 min, 13 g / 10 min, 14 g / 10 min, 15 g / 10 min, 16 g / 10 min, 17 g / 10 min, 18 g / 10 min, 19 g / 10 min or 20 g / 10 min.

[0062] The melt index of the second coating 122 is 3 g / 10 min to 10 g / 10 min, for example, 3 g / 10 min, 4 g / 10 min, 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 8 g / 10 min, 9 g / 10 min or 10 g / 10 min.

[0063] It should be noted that the above-mentioned melt index range refers to the process of melting the first coating 121 or the second coating 122 at 190±0.4°C and pouring it into the barrel of the measuring instrument. It is then pressed down with a punch weighing 2160±10g, and the number of grams of the glue squeezed out of the small hole at the bottom of the barrel within 10 minutes is measured.

[0064] In some embodiments, the length of the first cover film 121 along the second direction Y is greater than the length of the battery cell 100; and / or the length of the second cover film 122 along the second direction Y is greater than the length of the battery cell 100. In this way, during the process of covering the first cover film 121 or the second cover film 122, the alignment accuracy of the first cover film 121 or the second cover film 122 along the second direction Y can be reduced, thereby improving the installation efficiency of the first cover film 121 or the second cover film 122.

[0065] In some embodiments, the edge of the first covering film 121 away from the second covering film 122 may extend beyond the edge of the battery cell 100. When covering the first covering film 121, it is only necessary to control the distance between the first covering film 121 and the second covering film 122, so as to reduce the alignment accuracy of the first covering film 121 along the first direction X and improve the installation efficiency of the first covering film 121.

[0066] The materials of the first coating 121 and the second coating 122 include ethylene vinyl acetate copolymer (EVA), polyethylene octene copolymer (POE), polyvinyl butyral (PVB) or polyolefin thermoplastic elastomer (TPO).

[0067] The material of the first coating 121 and the material of the second coating 122 can be the same or different. When the material of the first coating 121 and the material of the second coating 122 are the same, the crosslinking degree of the first coating 121 can be greater than that of the second coating 122 by adjusting the average molecular weight of the first coating 121 and the second coating 122.

[0068] In some embodiments, the photovoltaic module may further include an adhesive film (not shown), which is located at least on the surface of the first cover film 121 and the second cover film 122 away from the cell 100. When the cell 100 is a back-contact cell, the adhesive film is also located on the surface of the cell 100 away from the welding ribbon 110.

[0069] The adhesive film may be an organic encapsulation film such as EVA film, POE film or PVB film.

[0070] In some embodiments, the photovoltaic module may further include a cover plate (not shown in the figures), which is located on the surface of the adhesive film away from the solar cell 100 .

[0071] The cover plate can be a glass cover plate, a plastic cover plate or other cover plate with light transmission function.

[0072] In some embodiments, the surface of the cover plate facing the adhesive film may be a concave-convex surface, thereby increasing the utilization rate of incident light.

[0073] In the photovoltaic module provided in the embodiment of the present application, adjacent battery cells 100 are connected by welding strips 110, and a first covering film 121 is provided at both ends of the battery cell 100 along the first direction X. The first covering film 121 is used to fix the position of the welding strip 110 at the two end parts of the battery cell 100 along the first direction X; the second covering film 122 is located between the two first covering films 121, and the second covering film 122 is used to fix the position of the welding strip 110 in the middle part of the battery cell 100. The crosslinking degree of the second covering film 122 is lower than that of the first covering film 121. This allows the first covering film 121 to have a stronger bonding strength than the second covering film 122. On the one hand, during the lamination process, the greater bonding strength of the first covering film 121 can prevent the occurrence of cold solder joints between the solder ribbon 110 and the ends of the cell 100. On the other hand, during the long-term use of the photovoltaic module, the greater bonding strength of the first covering film 121 helps improve the stability of the connection between the solder ribbon 110 and the ends of the cell 100, preventing connection failure between the solder ribbon 110 and the ends of the cell 100, thereby preventing power degradation of the photovoltaic module. Furthermore, when the first covering film 121 and the second covering film 122 are integral, the cooling and shrinkage of the second covering film 122 will pull on the first covering film 121, thereby reducing the pressure of the first covering film 121 on the solder ribbon 110, which can easily lead to a decrease in the connection strength between the solder ribbon 110 and the cell 100. The embodiment of the present application also provides a gap between the first coating 121 and the second coating 122. In this way, during the lamination process, the melting and cooling and solidification processes of the first coating 121 and the second coating 122 can be prevented from interfering with each other, thereby improving the stability of the first coating 121 fixing the welding strip 110.

[0074] Those skilled in the art will appreciate that the above-described embodiments 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 photovoltaic module, characterized in that: include: A plurality of battery cells arranged along a first direction; a welding ribbon extending along the first direction and used to connect two adjacent battery cells; a first covering film, the first covering film being located at both ends of the battery cell along the first direction and covering the surface of the battery cell, the first covering film extending along a second direction, the second direction intersecting the first direction, the plurality of welding ribbons along the second direction being located at portions of both ends of the battery cell along the first direction and between the first covering film and the battery cell; A second covering film, wherein the second covering film covers the surface of the battery cell and is located between two of the first covering films. The second covering film is spaced apart from the first covering film, and the cross-linking degree of the second covering film is less than that of the first covering film. A portion of the plurality of welding strips along the second direction that is located in the middle position of the battery cell along the first direction is located between the second covering film and the battery cell.

2. The photovoltaic module according to claim 1, characterized in that The gram weight of the first coating is greater than the gram weight of the second coating.

3. The photovoltaic module according to claim 2, characterized in that The first coating has a gram weight range of 130 g / m 2 ~180g / m 2 The second coating has a gram weight range of 80g / m 2 ~130g / m 2 .

4. The photovoltaic module according to claim 1, characterized in that Along the first direction, the width of the first coating is a first width, the length of the first coating covering the end of the welding strip is a first length, and the ratio of the first length to the first width is 0.5 to 0.

75.

5. The photovoltaic module according to claim 4, characterized in that: The first width is 13 mm to 20 mm; the first length is 10 mm to 15 mm.

6. The photovoltaic module according to claim 1, characterized in that Along the first direction, a gap width between the first coating and the second coating is 0.5 mm to 3 mm.

7. The photovoltaic module according to claim 1, characterized in that The melt index of the first coating is smaller than the melt index of the second coating.

8. The photovoltaic module according to claim 7, characterized in that: The melt index of the first coating is 8 g / 10 min to 20 g / 10 min; the melt index of the second coating is 3 g / 10 min to 10 g / 10 min.

9. The photovoltaic module according to claim 1, characterized in that: The length of the first covering film and / or the second covering film along the second direction is greater than the length of the battery cell.

10. The photovoltaic module according to claim 1 or 9, characterized in that: The edge of the first covering film is away from the edge of the second covering film and exceeds the edge of the battery cell.

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