Back contact battery assembly and photovoltaic system

Abstract

The utility model is suitable for the field of photovoltaic technology, and provides a back contact battery assembly and a photovoltaic system, and the back contact battery assembly comprises a plurality of battery pieces; the battery pack comprises a plurality of battery pieces, a plurality of insulating films and a plurality of battery pieces, the plurality of battery pieces are arranged in the insulating films at intervals, the solder strip is connected with the plurality of battery pieces along a first direction to form a battery string, the reflective films extend along the first direction to cover the intervals, and the reflective films are located between the insulating films and the battery pieces. The reflective films are arranged at the intervals, light of the intervals of the battery strings is fully reflected, light leakage is prevented, the reflective effect at the intervals is improved, the bus bars are arranged on the battery pieces to converge current carriers between the battery strings, and the insulating films are arranged between the bus bars and the welding strips to prevent the bus bars from short-circuiting the battery pieces. And the reflective film is arranged between the insulating film and the battery piece, so that the insulating film is prevented from shading, light in the space of the battery string can be fully utilized, and the power generation efficiency of the photovoltaic module is improved.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic technology, and in particular relates to a back contact battery module and a photovoltaic system. Background Technology

[0002] A photovoltaic module contains several strings of cells with gaps between adjacent strings. During lamination, a reflective film is usually placed at the gaps between the strings to reflect sunlight into the cells, thereby improving the efficiency of the photovoltaic module.

[0003] In existing technologies, reflective films are typically attached to the back glass of the EV back-contact battery module. When the busbar assembly is soldered to the back of the battery string, the insulating film within the busbar assembly partially blocks the reflective film, affecting the utilization of light within the battery string spacing and consequently impacting the photovoltaic module's power generation efficiency. Utility Model Content

[0004] This application provides a back-contact battery module, which aims to solve the problem that when the busbar module is welded to the back of the battery string, the insulating film in the busbar module will partially block the reflective film, affecting the utilization of light within the spacing of the battery string, and thus affecting the power generation efficiency of the photovoltaic module.

[0005] This application is implemented as follows: a back-contact battery assembly includes: a plurality of battery cells; a solder ribbon connecting the plurality of battery cells along a first direction to form a battery string, wherein the plurality of battery strings are spaced apart along a second direction; a busbar extending along the second direction to connect the plurality of battery strings; an insulating film disposed between the solder ribbon and the busbar, wherein the insulating film is disposed at the spaced intervals, the reflective film extending along the first direction to cover the spaced intervals, and the reflective film being located between the insulating film and the battery cells.

[0006] Optionally, the insulating film and the busbar are located at the middle of the battery cells at the end of the battery string.

[0007] Optionally, the plurality of solar cells are partially overlapped along the first direction.

[0008] Optionally, an adhesive layer is provided on the surface of the reflective film facing the battery cell, and the reflective film is connected to the backlight surface of two adjacent battery strings.

[0009] Optionally, the reflective film includes an aluminum film.

[0010] Optionally, the insulating film has multiple exposed areas, which expose the solder strips of the same polarity. The busbar is electrically connected to a portion of the solder strips through the exposed areas, and the insulating film insulates the busbars from another portion of the solder strips.

[0011] Optionally, the busbar includes a plurality of protruding structures and a plurality of connecting portions connected between the plurality of protruding structures, wherein the plurality of protruding structures extend into the corresponding exposed area and are electrically connected to a portion of the solder strip.

[0012] Optionally, the height of the protrusion structure is 100 to 600 micrometers.

[0013] Optionally, the top surface of the protrusion structure is a planar structure, and the protrusion structure and part of the welding strip surface are in surface contact.

[0014] Optionally, the width of the insulating film is greater than or equal to the width of the busbar.

[0015] This application forms a battery string from multiple battery cells, with the battery strings spaced apart. A reflective film is placed at the intervals to fully reflect the light between the battery strings, preventing light leakage and improving the reflectivity at the gaps. Busbars are provided on the battery cells to collect the charge carriers between the battery strings. An insulating film is placed between the busbars and the solder ribbon to prevent the busbars from short-circuiting the battery cells. Furthermore, the reflective film is placed between the insulating film and the battery cells to prevent the insulating film from blocking light. This allows for full utilization of the light within the battery string spacing, thereby improving the power generation efficiency of the photovoltaic module.

[0016] A photovoltaic system includes the aforementioned back-contact battery module. The photovoltaic system described in this application has the same technical effects as the aforementioned back-contact battery module, and will not be repeated here. Attached Figure Description

[0017] Figure 1 This is a partial structural diagram of the first type of back-contact battery assembly provided in the current application;

[0018] Figure 2 This is a partial structural schematic diagram of the second type of back-contact battery assembly provided in the current application;

[0019] Figure 3 This is a structural schematic diagram of the third type of back-contact battery assembly provided in the current application.

[0020] Explanation of reference numerals in the attached figures:

[0021] 100. Battery cell; 200. Welding strip; 300. Battery string; 400. Busbar; 401. Raised structure; 402. Connecting part; 500. Insulating film; 501. Through hole; 600. Reflective film. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0023] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0028] like Figure 3 As shown, a back-contact battery assembly includes multiple battery cells 100. Solder ribbons 200 connect the multiple battery cells 100 along a first direction to form battery strings 300. The multiple battery strings 300 are spaced apart along a second direction. Busbars 400 extend along the second direction to connect the multiple battery strings 300. An insulating film 500 and a busbar 400 are arranged in the same direction. The insulating film 500 is disposed between the solder ribbons 200 and the busbars 400. A reflective film 600 is disposed at the intervals. The reflective film 600 extends along the first direction to cover the intervals. The reflective film 600 is located between the insulating film 500 and the battery cells 100. This application forms a battery string 300 from multiple battery cells 100, with the battery strings 300 spaced apart. A reflective film 600 is disposed at the intervals to fully reflect the light between the battery strings 300, preventing light leakage and improving the reflectivity at the gaps. A busbar 400 is disposed on the battery cell 100 to collect the charge carriers between the battery strings 300. In addition, an insulating film 500 is disposed between the busbar 400 and the solder ribbon 200 to prevent the busbar 400 from short-circuiting the battery cell 100. The reflective film 600 is disposed between the insulating film 500 and the battery cell 100 to prevent the insulating film 500 from blocking light. This allows for full utilization of the light within the spacing between the battery strings 300, thereby improving the power generation efficiency of the photovoltaic module.

[0029] In this embodiment, the battery string 300 includes multiple battery cells 100, which are connected in series via solder ribbons 200. There are multiple solder ribbons 200, including solder ribbons of two polarities, which are respectively connected to electrodes of two different polarities. It can also be understood that the battery string 300 may include two battery cells 100 connected in series, three battery cells 100 connected in series, or a greater number of battery cells 100, depending on the actual usage.

[0030] For example, the insulating film 500 can be an insulating adhesive, or a non-conductive tape or insulating film 500, such as a PET or PI tape with acrylic or silicone, or a PET or PI substrate coated with ethylene-vinyl acetate copolymer or hot melt adhesive on one or both sides. It is understood that the insulating film 500 may contain materials such as ethylene-vinyl acetate copolymer, resin materials, polyimide or polypropylene or polyethylene, and may also contain an acrylic adhesive layer.

[0031] Preferably, the reflective film 600 comprises an aluminum film. Of course, in other embodiments, the reflective film 600 may also be a PET film, a PC film, a silver-plated composite film, etc., and this application does not impose any limitations on this.

[0032] In this embodiment, the second direction intersects the first direction. Specifically, the second direction can be perpendicular to the first direction. For example, the first direction can be the length direction of the battery cell 100, and the second direction can be the width direction of the battery cell 100.

[0033] The insulating film 500 and the busbar 400 are located in the middle of the battery cell 100 at the end of the battery string 300. This effectively shortens the current transmission distance and reduces the transmission loss of the solder strip 200 and the risk of edge microcracks.

[0034] Multiple solar cells 100 are partially overlapped along a first direction. The partial overlap of the solar cells 100 forms a battery string 300. The contact areas between the overlaps are not electrically connected; that is, no conductive adhesive or other bonding agent is needed between the overlapping areas. The solar cells 100 are simply overlapped. In the battery string 300, the overlapping areas of adjacent solar cells 100 are provided with solder ribbons 200 to securely connect adjacent solar cells 100. Thus, there are no gaps between the solar cells 100, allowing for better concealment of the solder ribbons 200. Furthermore, the overlap of the solar cells 100 allows for a smaller size of the battery string 300, resulting in a smaller footprint. In other words, with a fixed size for the battery string 300, more solar cells 100 can be placed, increasing the power output of the battery string 300 and reducing the cost per watt.

[0035] An adhesive layer is applied to the surface of the reflective film 600 facing the solar cell 100, connecting the reflective film 600 to the backlight surfaces of two adjacent solar cell strings 300. In traditional photovoltaic module manufacturing processes, it may be necessary to additionally adhere an EV back contact solar cell module film to the back glass to fix the reflective film 600 to the back glass. This requires adding a film-applying process to the module encapsulation line, applying the EV back contact solar cell module film with the reflective strip to the back glass at the corresponding gap before lamination using a film-applying device. This process is cumbersome. However, by directly applying the reflective film 600 and adhesive layer to the backlight surface of the solar cell string 300, the manufacturing process is simplified, and production costs are reduced. Specifically, the adhesive layer can be made of acrylic adhesive or thermosetting insulating adhesive. The adhesive layer not only serves a connecting function but also fixes the solar cell string 300 during lamination, preventing displacement. This multi-functional application reduces the number of steps in photovoltaic module manufacturing and saves materials. This fixing effect helps maintain the structural stability of the photovoltaic module, improving its reliability and durability.

[0036] like Figure 2 As shown, the insulating film 500 has multiple exposed areas, each exposing solder ribbons 200 of the same polarity. The busbar 400 is electrically connected to a portion of the solder ribbons 200 through these exposed areas, and the insulating film 500 insulates the busbar 400 from another portion of the solder ribbons 200. The form of the exposed areas formed by the insulating film 500 is not limited, as long as the solder ribbons 200 are exposed; this application does not impose any limitations. For example, the insulating film 500 includes multiple spaced-apart segmented films, and the exposed areas can be formed in the gaps between adjacent segmented films. Thus, the segmented films only cover the solder ribbons 200 that need insulation, while the solder ribbons 200 welded to the busbar 400 can be completely adhered to the corresponding electrode area of ​​the battery cell 100 due to the presence of the exposed areas, allowing the solder ribbons 200 to connect to more fine grids. Preferably, the insulating film 500 is provided with through holes 501 forming the exposed areas. That is, the through-hole 501 extending along the thickness direction of the insulating film 500 forms an exposed area. The insulating film 500 covers the solder ribbon 200, and because the insulating film 500 has through-hole 501, the through-hole 501 can expose the solder ribbon 200 of the same polarity, so that the busbar 400 can be connected to the solder ribbon 200 at the through-hole 501. The insulating film 500 can prevent the busbar 400 from short-circuiting the cell 100. Furthermore, due to the presence of the through-hole 501, the insulating film 500 does not hinder the conductive connection between the busbar 400 and the solder ribbon 200, and it is also convenient to completely attach the solder ribbon 200 to the cell 100, so that the solder ribbon 200 can be connected to more grids.

[0037] like Figure 1As shown, the busbar 400 includes multiple protruding structures 401 and multiple connecting portions 402 connected between the multiple protruding structures 401. The multiple protruding structures 401 extend into corresponding exposed areas and are electrically connected to portions of the solder ribbon 200. In this embodiment, the busbar 400 has multiple protruding structures 401 and multiple connecting portions 402 connected between the multiple protruding structures 401. The protruding structures 401 are bent portions of the busbar 400, and the connecting portions 402 are straight portions of the busbar 400. The protruding structures 401 extend into the exposed areas and are electrically connected to the exposed solder ribbon 200. This allows the protruding structures 401 to make closer contact with the solder ribbon 200, increasing the contact area, thereby reducing contact resistance and improving conductivity. This design helps reduce energy loss and improve the power generation efficiency of the battery module. Furthermore, the close contact between the protruding structures 401 and the solder ribbon 200 not only improves conductivity but also enhances the reliability of the connection. In harsh environments such as vibration and impact, this tight connection reduces circuit failures caused by loosening or detachment. The design of the raised structure 401 makes the connection between the busbar 400 and the solder ribbon 200 more convenient. During the installation of the busbar 400, a conductive connection can be achieved simply by aligning the raised structure 401 with the exposed solder ribbon 200 and applying appropriate pressure and temperature. This allows for precise control of the local temperature of the busbar 400, preventing premature melting of the solder paste layer or adhesive film of the solder ribbon 200 within the battery module due to overheating, which could cause the backsheet glass and the battery cells 100 to stick together and affect subsequent module assembly. Due to the special design of the busbar 400, the stable connection between the busbar 400 and the solder ribbon 200 helps fill gaps in the exposed area and improves the reliability of the battery module.

[0038] It should be noted that, based on the design of the busbar 400 with the raised structure 401, the thickness of the insulating film 500 can be 300-600 micrometers. Preferably, the thickness of the insulating layer is between 500-600 micrometers. In such embodiments, the thickness of the insulating layer can be 500 micrometers, 520 micrometers, 550 micrometers, 580 micrometers, 600 micrometers, or any value between 500-600 micrometers, and is not specifically limited here. Within this range, the insulating film 500 has good insulation effect, is easy to apply, is not easily deformed by pulling, and will not be damaged during long-term insulation. Furthermore, it can avoid the risk of short circuit caused by the burrs on the edge of the busbar 400 puncturing the insulating film 500.

[0039] In some embodiments, the top surface of the protrusion structure 401 is a planar structure, and the protrusion structure 401 and the solder ribbon 200 are in surface-to-surface contact. The busbar 400 and the solder ribbon 200 are stably connected, and the protrusion structure 401 can make closer contact with the solder ribbon 200, increasing the contact area, thereby reducing contact resistance and improving conductivity. Furthermore, during the lamination process, the surface-to-surface contact between the protrusion structure 401 and the solder ribbon 200 disperses the lamination pressure, reducing the risk of microcracks in the solar cell 100.

[0040] In some embodiments, the height of the protrusion structure 401 is 100–600 micrometers. Preferably, the height of the protrusion structure 401 is 500–600 micrometers. In such embodiments, the height of the protrusion structure 401 can be 500 micrometers, 520 micrometers, 550 micrometers, 580 micrometers, 600 micrometers, or any value between 500 and 600 micrometers, and is not specifically limited herein. Understandably, the height of the protrusion structure 401 is adapted to the thickness of the insulating film 500 to ensure that part of the busbar 400 extends into the insulation, and the other part of the busbar 400 fits well with the insulating film 500, reducing gaps and preventing air from entering during subsequent encapsulation, thereby improving the reliability of the battery assembly.

[0041] In some embodiments, the outer peripheral wall of the protrusion 401 and the inner peripheral wall of the through hole 501 are in close contact with each other. That is, there is no gap between the protrusion 401 and the through hole 501, so that air will not enter after encapsulation, thus improving the reliability of the battery assembly.

[0042] The width of the insulating film 500 is greater than or equal to the width of the busbar 400. If the width of the insulating film 500 is too narrow, the busbar 400 will be exposed, posing a risk of short circuit due to contact between the busbar 400 and the non-standard solder ribbon 200. The fact that the width of the insulating film 500 is greater than or equal to the width of the busbar 400 can completely isolate the busbar 400 and the non-standard solder ribbon 200, thus avoiding the risk of short circuit.

[0043] A photovoltaic system includes the aforementioned back-contact battery module. In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants, and can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system grid as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0044] In the description of this specification, the use of terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., refers to specific features, structures, materials, or characteristics described in connection with the embodiments or examples, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0045] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A back-contact battery assembly, characterized in that, include: Multiple battery cells; A solder strip connects multiple battery cells along a first direction to form a battery string, with the multiple battery strings spaced apart along a second direction; a busbar extends along the second direction to connect the multiple battery strings; an insulating film is arranged in the same direction as the busbar and is disposed between the solder strip and the busbar; a reflective film is disposed at the interval, extends along the first direction to cover the interval, and is located between the insulating film and the battery cells.

2. The back contact battery assembly as described in claim 1, characterized in that, The insulating film and the busbar are located at the middle of the battery cells at the end of the battery string.

3. The back contact battery assembly as described in claim 1, characterized in that, The multiple battery cells are partially overlapped along the first direction.

4. The back contact battery assembly as described in claim 1, characterized in that, An adhesive layer is provided on the surface of the reflective film facing the battery cell, and the reflective film is connected to the backlight surface of two adjacent battery strings.

5. The back contact battery assembly as described in claim 1, characterized in that, The reflective film includes an aluminum film.

6. The back contact battery assembly as claimed in claim 1, characterized in that, The insulating film has multiple exposed areas, which expose the solder strips of the same polarity. The busbar is electrically connected to a portion of the solder strips through the exposed areas, and the insulating film insulates the busbars from another portion of the solder strips.

7. The back contact battery assembly as described in claim 6, characterized in that, The busbar includes multiple protruding structures and multiple connecting portions connected between the multiple protruding structures. The multiple protruding structures extend into the corresponding exposed areas and are electrically connected to a portion of the solder strip.

8. The back contact battery assembly as claimed in claim 7, characterized in that, The height of the protrusion structure is 100–600 micrometers.

9. The back contact battery assembly as claimed in claim 7, characterized in that, The top surface of the protruding structure is a planar structure, and the protruding structure and part of the welding strip surface are in surface contact.

10. The back contact battery assembly as claimed in claim 1, characterized in that, The width of the insulating film is greater than or equal to the width of the busbar.

11. A photovoltaic system, characterized in that, Includes the back contact battery assembly as described in any one of claims 1-10.

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